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  1. Antibody-Mediated Internalization of Infectious HIV-1 Virions Differs among Antibody Isotypes and Subclasses.

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    Tay, Matthew Zirui; Liu, Pinghuang; Williams, LaTonya D; McRaven, Michael D; Sawant, Sheetal; Gurley, Thaddeus C; Xu, Thomas T; Dennison, S Moses; Liao, Hua-Xin; Chenine, Agnès-Laurence; Alam, S Munir; Moody, M Anthony; Hope, Thomas J; Haynes, Barton F; Tomaras, Georgia D

    2016-08-01

    Emerging data support a role for antibody Fc-mediated antiviral activity in vaccine efficacy and in the control of HIV-1 replication by broadly neutralizing antibodies. Antibody-mediated virus internalization is an Fc-mediated function that may act at the portal of entry whereby effector cells may be triggered by pre-existing antibodies to prevent HIV-1 acquisition. Understanding the capacity of HIV-1 antibodies in mediating internalization of HIV-1 virions by primary monocytes is critical to understanding their full antiviral potency. Antibody isotypes/subclasses differ in functional profile, with consequences for their antiviral activity. For instance, in the RV144 vaccine trial that achieved partial efficacy, Env IgA correlated with increased risk of HIV-1 infection (i.e. decreased vaccine efficacy), whereas V1-V2 IgG3 correlated with decreased risk of HIV-1 infection (i.e. increased vaccine efficacy). Thus, understanding the different functional attributes of HIV-1 specific IgG1, IgG3 and IgA antibodies will help define the mechanisms of immune protection. Here, we utilized an in vitro flow cytometric method utilizing primary monocytes as phagocytes and infectious HIV-1 virions as targets to determine the capacity of Env IgA (IgA1, IgA2), IgG1 and IgG3 antibodies to mediate HIV-1 infectious virion internalization. Importantly, both broadly neutralizing antibodies (i.e. PG9, 2G12, CH31, VRC01 IgG) and non-broadly neutralizing antibodies (i.e. 7B2 mAb, mucosal HIV-1+ IgG) mediated internalization of HIV-1 virions. Furthermore, we found that Env IgG3 of multiple specificities (i.e. CD4bs, V1-V2 and gp41) mediated increased infectious virion internalization over Env IgG1 of the same specificity, while Env IgA mediated decreased infectious virion internalization compared to IgG1. These data demonstrate that antibody-mediated internalization of HIV-1 virions depends on antibody specificity and isotype. Evaluation of the phagocytic potency of vaccine

  2. Antibody Fc engineering improves frequency and promotes kinetic boosting of serial killing mediated by NK cells

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    Romain, Gabrielle; Senyukov, Vladimir; Rey-Villamizar, Nicolas; Merouane, Amine; Kelton, William; Liadi, Ivan; Mahendra, Ankit; Charab, Wissam; Georgiou, George; Roysam, Badrinath; Lee, Dean A.

    2014-01-01

    The efficacy of most therapeutic monoclonal antibodies (mAbs) targeting tumor antigens results primarily from their ability to elicit potent cytotoxicity through effector-mediated functions. We have engineered the fragment crystallizable (Fc) region of the immunoglobulin G (IgG) mAb, HuM195, targeting the leukemic antigen CD33, by introducing the triple mutation Ser293Asp/Ala330Leu/Ile332Glu (DLE), and developed Time-lapse Imaging Microscopy in Nanowell Grids to analyze antibody-dependent cell-mediated cytotoxicity kinetics of thousands of individual natural killer (NK) cells and mAb-coated target cells. We demonstrate that the DLE-HuM195 antibody increases both the quality and the quantity of NK cell-mediated antibody-dependent cytotoxicity by endowing more NK cells to participate in cytotoxicity via accrued CD16-mediated signaling and by increasing serial killing of target cells. NK cells encountering targets coated with DLE-HuM195 induce rapid target cell apoptosis by promoting simultaneous conjugates to multiple target cells and induce apoptosis in twice the number of target cells within the same period as the wild-type mAb. Enhanced target killing was also associated with increased frequency of NK cells undergoing apoptosis, but this effect was donor-dependent. Antibody-based therapies targeting tumor antigens will benefit from a better understanding of cell-mediated tumor elimination, and our work opens further opportunities for the therapeutic targeting of CD33 in the treatment of acute myeloid leukemia. PMID:25232058

  3. Antibody-mediated rejection across solid organ transplants: manifestations, mechanisms, and therapies.

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    Valenzuela, Nicole M; Reed, Elaine F

    2017-06-30

    Solid organ transplantation is a curative therapy for hundreds of thousands of patients with end-stage organ failure. However, long-term outcomes have not improved, and nearly half of transplant recipients will lose their allografts by 10 years after transplant. One of the major challenges facing clinical transplantation is antibody-mediated rejection (AMR) caused by anti-donor HLA antibodies. AMR is highly associated with graft loss, but unfortunately there are few efficacious therapies to prevent and reverse AMR. This Review describes the clinical and histological manifestations of AMR, and discusses the immunopathological mechanisms contributing to antibody-mediated allograft injury as well as current and emerging therapies.

  4. Treatment of Antibody-Mediated Renal Allograft Rejection: Improving Step by Step

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    Nils Lachmann

    2017-01-01

    Full Text Available Throughout the past years we stepwise modified our immunosuppressive treatment regimen for patients with antibody-mediated rejection (ABMR. Here, we describe three consecutive groups treated with different regimens. From 2005 until 2008, we treated all patients with biopsy-proven ABMR with rituximab (500 mg, low-dose (30 g intravenous immunoglobulins (IVIG, and plasmapheresis (PPH, 6x (group RLP, n=12. Between 2009 and June 2010, patients received bortezomib (1.3 mg/m2, 4x together with low-dose IVIG and PPH (group BLP, n=11. In July 2010, we increased the IVIG dose and treated all subsequent patients with bortezomib, high-dose IVIG (1.5 g/kg, and PPH (group BHP, n=11. Graft survival at three years after treatment was 73% in group BHP as compared to 45% in group BLP and 25% in group RLP. At six months after treatment median serum creatinine was 2.1 mg/dL, 2.9 mg/dL, and 4.2 mg/dL in groups BHP, BLP, and RLP, respectively (p=0.02. Following treatment, a significant decrease of donor-specific HLA antibody (DSA mean fluorescence intensity from 8467±6876 to 5221±4711 (p=0.01 was observed in group BHP, but not in the other groups. Our results indicate that graft survival, graft function, and DSA levels could be improved along with stepwise modifications to our treatment regimen, that is, the introduction of bortezomib and high-dose IVIG treatment.

  5. Daratumumab-mediated lysis of primary multiple myeloma cells is enhanced in combination with the human anti-KIR antibody IPH2102 and lenalidomide

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    Nijhof, I. S.; Lammerts van Bueren, J. J.; van Kessel, B.

    2015-01-01

    Despite recent treatment improvements, multiple myeloma remains an incurable disease. Since antibody-dependent cell-mediated cytotoxicity is an important effector mechanism of daratumumab, we explored the possibility of improving daratumumab-mediated cell-mediated cytotoxicity by blocking natural...... killer cell inhibitory receptors with the human monoclonal anti-KIR antibody IPH2102, next to activation of natural killer cells with the immune modulatory drug lenalidomide. In 4-hour antibody-dependent cell-mediated cytotoxicity assays, IPH2102 did not induce lysis of multiple myeloma cell lines...... effective treatment strategies can be designed for multiple myeloma by combining daratumumab with agents that independently modulate natural killer cell function....

  6. Antibody-Mediated Rejection in a Blood Group A-Transgenic Mouse Model of ABO-Incompatible Heart Transplantation.

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    Motyka, Bruce; Fisicaro, Nella; Wang, Szu-I; Kratochvil, Annetta; Labonte, Katrina; Tao, Kesheng; Pearcey, Jean; Marshall, Thuraya; Mengel, Michael; Sis, Banu; Fan, Xiaohu; dʼApice, Anthony J F; Cowan, Peter J; West, Lori J

    2016-06-01

    ABO-incompatible (ABOi) organ transplantation is performed owing to unremitting donor shortages. Defining mechanisms of antibody-mediated rejection, accommodation, and tolerance of ABOi grafts is limited by lack of a suitable animal model. We report generation and characterization of a murine model to enable study of immunobiology in the setting of ABOi transplantation. Transgenesis of a construct containing human A1- and H-transferases under control of the ICAM-2 promoter was performed in C57BL/6 (B6) mice. A-transgenic (A-Tg) mice were assessed for A-antigen expression by histology and flow cytometry. B6 wild-type (WT) mice were sensitized with blood group A-human erythrocytes; others received passive anti-A monoclonal antibody and complement after heart transplant. Serum anti-A antibodies were assessed by hemagglutination. "A-into-O" transplantation (major histocompatibility complex syngeneic) was modeled by transplanting hearts from A-Tg mice into sensitized or nonsensitized WT mice. Antibody-mediated rejection was assessed by morphology/immunohistochemistry. A-Tg mice expressed A-antigen on vascular endothelium and other cells including erythrocytes. Antibody-mediated rejection was evident in 15/17 A-Tg grafts in sensitized WT recipients (median titer, 1:512), with 2 showing hyperacute rejection and rapid cessation of graft pulsation. Hyperacute rejection was observed in 8/8 A-Tg grafts after passive transfer of anti-A antibody and complement into nonsensitized recipients. Antibody-mediated rejection was not observed in A-Tg grafts transplanted into nonsensitized mice. A-Tg heart grafts transplanted into WT mice with abundant anti-A antibody manifests characteristic features of antibody-mediated rejection. These findings demonstrate an effective murine model to facilitate study of immunologic features of ABOi transplantation and to improve potential diagnostic and therapeutic strategies.

  7. Antibody-Mediated Rejection: Pathogenesis, Prevention, Treatment, and Outcomes

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    Olivia R. Blume

    2012-01-01

    Full Text Available Antibody-mediated rejection (AMR is a major cause of late kidney transplant failure. It is important to have an understanding of human-leukocyte antigen (HLA typing including well-designed studies to determine anti-MHC-class-I-related chain A (MICA and antibody rejection pathogenesis. This can allow for more specific diagnosis and treatment which may improve long-term graft function. HLA-specific antibody detection prior to transplantation allows one to help determine the risk for AMR while detection of DSA along with a biopsy confirms it. It is now appreciated that biopsy for AMR does not have to include diffuse C4d, but does require a closer look at peritubular capillary microvasculature. Although plasmapheresis (PP is effective in removing alloantibodies (DSAs from the circulation, rebound synthesis of alloantibodies can occur. Splenectomy is used in desensitization protocols for ABO incompatible transplants as well as being found to treat AMR refractory to conventional treatment. Also used are agents targeted for plasma cells, B cells, and the complement cascade which are bortezomib rituximab and eculizumab, respectively.

  8. Antibody-mediated rejection in kidney transplantation: a review of pathophysiology, diagnosis, and treatment options.

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    Kim, Miae; Martin, Spencer T; Townsend, Keri R; Gabardi, Steven

    2014-07-01

    Antibody-mediated rejection (AMR), also known as B-cell-mediated or humoral rejection, is a significant complication after kidney transplantation that carries a poor prognosis. Although fewer than 10% of kidney transplant patients experience AMR, as many as 30% of these patients experience graft loss as a consequence. Although AMR is mediated by antibodies against an allograft and results in histologic changes in allograft vasculature that differ from cellular rejection, it has not been recognized as a separate disease process until recently. With an improved understanding about the importance of the development of antibodies against allografts as well as complement activation, significant advances have occurred in the treatment of AMR. The standard of care for AMR includes plasmapheresis and intravenous immunoglobulin that remove and neutralize antibodies, respectively. Agents targeting B cells (rituximab and alemtuzumab), plasma cells (bortezomib), and the complement system (eculizumab) have also been used successfully to treat AMR in kidney transplant recipients. However, the high cost of these medications, their use for unlabeled indications, and a lack of prospective studies evaluating their efficacy and safety limit the routine use of these agents in the treatment of AMR in kidney transplant recipients. © 2014 Pharmacotherapy Publications, Inc.

  9. C4d-negative antibody-mediated rejection with high anti-angiotensin II type I receptor antibodies in absence of donor-specific antibodies.

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    Fuss, Alexander; Hope, Christopher M; Deayton, Susan; Bennett, Greg Donald; Holdsworth, Rhonda; Carroll, Robert P; Coates, P Toby H

    2015-07-01

    Acute antibody-mediated rejection can occur in absence of circulating donor-specific antibodies. Agonistic antibodies targeting the anti-angiotensin II type 1 receptor (anti-AT1 R) are emerging as important non-human leucocyte antigen (HLA) antibodies. Elevated levels of anti-angiotensin II receptor antibodies were first observed in kidney transplant recipients with malignant hypertension and allograft rejection. They have now been studied in three separate kidney transplant populations and associate to frequency of rejection, severity of rejection and graft failure. We report 11 cases of biopsy-proven, Complement 4 fragment d (C4d)-negative, acute rejection occurring without circulating donor-specific anti-HLA antibodies. In eight cases, anti-angiotensin receptor antibodies were retrospectively examined. The remaining three subjects were identified from our centre's newly instituted routine anti-angiotensin receptor antibody screening. All subjects fulfilled Banff 2013 criteria for antibody-mediated rejection and all responded to anti-rejection therapy, which included plasma exchange and angiotensin receptor blocker therapy. These cases support the routine assessment of anti-AT1 R antibodies in kidney transplant recipients to identify subjects at risk. Further studies will need to determine optimal assessment protocol and the effectiveness of pre-emptive treatment with angiotensin receptor blockers. © 2015 Asian Pacific Society of Nephrology.

  10. Eculizumab for the Treatment of Severe Antibody-Mediated Rejection: A Case Report and Review of the Literature

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    Duy Tran

    2016-01-01

    Full Text Available In renal transplantation, treatment options for antibody-mediated rejection are limited. Here, we report a case of severe AMR treated with eculizumab. A 50-year-old woman known for end stage kidney disease secondary to IgA nephropathy received a kidney transplant from a 50-year-old deceased donor. At 5 months after transplantation, she presented with acute graft dysfunction and biopsy showed a severe antibody-mediated rejection associated with thrombotic microangiopathy. Despite an aggressive conventional immunosuppressive regimen, signs of rejection persisted and the patient was treated with 3 doses of eculizumab. Following the therapy, markers of TMA improved and graft function stabilized. However, ongoing signs of rejection remained in the repeated biopsy. In kidney transplantation, eculizumab is an expensive treatment and its role in the treatment of antibody-mediated rejection remains to be determined.

  11. Ocaratuzumab, an Fc-engineered antibody demonstrates enhanced antibody-dependent cell-mediated cytotoxicity in chronic lymphocytic leukemia.

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    Cheney, Carolyn M; Stephens, Deborah M; Mo, Xiaokui; Rafiq, Sarwish; Butchar, Jonathan; Flynn, Joseph M; Jones, Jeffrey A; Maddocks, Kami; O'Reilly, Adrienne; Ramachandran, Abhijit; Tridandapani, Susheela; Muthusamy, Natarajan; Byrd, John C

    2014-01-01

    Chronic lymphocytic leukemia (CLL) is common in both developed and developing nations where the need for inexpensive and convenient administration of therapy is apparent. Ocaratuzumab is a novel Fc-engineered humanized IgG1 anti-CD20 monoclonal antibody (mAb) designed for effective antibody-dependent cell-mediated cytotoxicity (ADCC) at very low concentrations that may facilitate sub-cutaneous (vs. intravenous) dosing. Here, we report ocaratuzumab's potency against CLL cells. In vitro assessment of ocaratuzumab's direct cytotoxicity (DC), complement-dependent cytotoxicity (CDC), antibody-dependent cellular phagocytosis (ADCP), and ADCC was performed on CLL cells. Ocaratuzumab induced DC, CDC, and ADCP similarly to rituximab or ofatumumab (anti-CD20 mAbs). However, ocaratuzumab showed an advantage in NK cell-mediated ADCC over these antibodies. In allogeneic ADCC, [E:T (effector:target) ratios = 25:1, 12:1, 6:1], ocaratuzumab (10 µg/mL) improved ADCC by ~3-fold compared with rituximab or ofatumumab (P<0.001 all tested E:T ratios). Notably, the superiority of ocaratuzumab-induced ADCC was observed at low concentrations (0.1-10 ug/ml; P<0.03; allogeneic assays). In extended allogeneic ADCC E:T titration, ocaratuzumab (0.1 µg/mL) demonstrated 19.4% more cytotoxicity than rituximab (E:T = 0.38:1; P = 0.0066) and 21.5% more cytotoxicity than ofatumumab (E:T = 1.5:1; P = 0.0015). In autologous ADCC, ocaratuzumab (10 µg/mL) demonstrated ~1.5-fold increase in cytotoxicity compared with rituximab or ofatumumab at all E:T ratios tested (E:Ts = 25:1,12:1,6:1; all P<0.001). Obinutuzumab, a glyco-engineered anti-CD20 mAb, showed no improvement in ADCC activity compared with ocaratuzumab. The enhanced ADCC of ocaratuzumab suggests that it may be effective at low concentrations. If supported by clinical investigation, this feature could potentially allow for subcutaneous dosing at low doses that could expand the potential of administering chemoimmunotherapy in developing

  12. Probable C4d-negative accelerated acute antibody-mediated rejection due to non-HLA antibodies.

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    Niikura, Takahito; Yamamoto, Izumi; Nakada, Yasuyuki; Kamejima, Sahoko; Katsumata, Haruki; Yamakawa, Takafumi; Furuya, Maiko; Mafune, Aki; Kobayashi, Akimitsu; Tanno, Yudo; Miki, Jun; Yamada, Hiroki; Ohkido, Ichiro; Tsuboi, Nobuo; Yamamoto, Hiroyasu; Yokoo, Takashi

    2015-07-01

    We report a case of probable C4d-negative accelerated acute antibody-mediated rejection due to non-HLA antibodies. A 44 year-old male was admitted to our hospital for a kidney transplant. The donor, his wife, was an ABO minor mismatch (blood type O to A) and had Gitelman syndrome. Graft function was delayed; his serum creatinine level was 10.1 mg/dL at 3 days after transplantation. Open biopsy was performed immediately; no venous thrombosis was observed during surgery. Histology revealed moderate peritubular capillaritis and mild glomerulitis without C4d immunoreactivity. Flow cytometric crossmatching was positive, but no panel-reactive antibodies against HLA or donor-specific antibodies (DSAbs) to major histocompatibility complex class I-related chain A (MICA) were detected. Taken together, we diagnosed him with probable C4d-negative accelerated antibody-mediated rejection due to non-HLA, non-MICA antibodies, the patient was treated with steroid pulse therapy (methylprednisolone 500 mg/day for 3 days), plasma exchange, intravenous immunoglobulin (40 g/body), and rituximab (200 mg/body) were performed. Biopsy at 58 days after transplantation, at which time S-Cr levels were 1.56 mg/dL, found no evidence of rejection. This case, presented with a review of relevant literature, demonstrates that probable C4d-negative accelerated acute AMR can result from non-HLA antibodies. © 2015 Asian Pacific Society of Nephrology.

  13. Antibody-mediated delivery of interleukin 4 to the neo-vasculature reduces chronic skin inflammation.

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    Hemmerle, Teresa; Zgraggen, Silvana; Matasci, Mattia; Halin, Cornelia; Detmar, Michael; Neri, Dario

    2014-11-01

    The antibody-mediated delivery of cytokines ("immunocytokines") to sites of pathological angiogenesis represents an attractive strategy for the development of innovative biopharmaceuticals, capable of modulating the activity of the immune system in cancer and in chronic inflammatory conditions. Recombinant IL4 has previously been shown to be therapeutically active in patients with psoriasis. The antibody-mediated delivery of this cytokine to sites of chronic skin inflammatory conditions should lead to an improved potency and selectivity, compared to non-targeted IL4. The therapeutic activity of F8-IL4, a fusion protein of the F8 antibody (specific to the alternatively-spliced EDA domain of fibronectin) with murine IL4, was investigated in three immunocompetent mouse models of skin inflammation: two induced by the TLR7/8 ligand imiquimod (in Balb/c and C57BL/6) and one mediated by the over-expression of VEGF-A. The EDA domain of fibronectin, a marker for angiogenesis, is expressed in the inflamed skin in all three models and F8-IL4 selectively localized to inflamed skin lesions following intravenous administration. The F8-IL4 fusion protein mediated a therapeutic benefit, which was superior to the one of a non-targeted version of IL4 and led to increased levels of key regulatory cytokines (including IL5, IL10, IL13, and IL27) in the inflamed skin, while IL2 levels were not affected in all treatment groups. A murine version of etanercept and a murine anti-IL17 antibody were used as positive control in the therapy experiments. Skin inflammatory lesions can be selectively targeted using anti-EDA antibody-cytokine fusion proteins and the pharmacodelivery of IL4 confers a therapeutic benefit by shifting the cytokine balance. Copyright © 2014 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

  14. Antibody-mediated phagocytosis contributes to the anti-tumor activity of the therapeutic antibody daratumumab in lymphoma and multiple myeloma

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    Overdijk, M. B.; Verploegen, S.; Bogels, M.

    2015-01-01

    Daratumumab (DARA) is a human CD38-specific IgG1 antibody that is in clinical development for the treatment of multiple myeloma (MM). The potential for IgG1 antibodies to induce macrophage-mediated phagocytosis, in combination with the known presence of macrophages in the tumor microenvironment...... in MM and other hematological tumors, led us to investigate the contribution of antibody-dependent, macrophage-mediated phagocytosis to DARA's mechanism of action. Live cell imaging revealed that DARA efficiently induced macrophage-mediated phagocytosis, in which individual macrophages rapidly...... and sequentially engulfed multiple tumor cells. DARA-dependent phagocytosis by mouse and human macrophages was also observed in an in vitro flow cytometry assay, using a range of MM and Burkitt's lymphoma cell lines. Phagocytosis contributed to DARA's anti-tumor activity in vivo, in both a subcutaneous...

  15. Autologous Hematopoietic Stem Cell Transplantation to Prevent Antibody Mediated Rejection After Vascularized Composite Allotransplantation

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    2017-10-01

    Award Number: W81XWH-16-1-0664 TITLE: Autologous Hematopoietic Stem Cell Transplantation to Prevent Antibody-Mediated Rejection after...Annual 3. DATES COVERED 15 Sep 2016 – 14 Sep 2017 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Autologous Hematopoietic Stem Cell Transplantation to...sensitization, autologous hematopoietic stem cell transplantation, antibody mediated rejection, donor specific antibodies 16. SECURITY CLASSIFICATION OF

  16. Postoperative rebound of antiblood type antibodies and antibody-mediated rejection after ABO-incompatible living-related kidney transplantation.

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    Ishida, Hideki; Kondo, Tsunenori; Shimizu, Tomokazu; Nozaki, Taiji; Tanabe, Kazunari

    2015-03-01

    The purpose of this study is to examine whether postoperative antiblood type antibody rebound is attributed to kidney allograft rejection in ABO blood type-incompatible (ABO-I) living-related kidney transplantation (KTx). A total of 191 ABO-I recipients who received ABO-I living-related KTx between 2001 and 2013 were divided into two groups: Group 1 consisted of low rebound [(≦1:32), N = 170] and Group 2 consisted of high rebound [(≧1:64), N = 21], according to the levels of the rebounded antiblood type antibodies within 1 year after transplantation. No prophylactic treatment for rejection was administered for elevated antiblood type antibodies, regardless of the levels of the rebounded antibodies. Within 1 year after transplantation, T-cell-mediated rejection was observed in 13 of 170 recipients (13/170, 8%) in Group 1 and in 2 of 21 recipients (2/21, 10%) in Group 2 (Groups 1 vs. 2, P = 0.432). Antibody-mediated rejection was observed in 15 of 170 recipients (15/170, 9%) and 2 of 21 recipients (2/21, 10%) in Groups 1 and 2, respectively (P = 0.898). In this study, we found no correlation between the postoperative antiblood type antibody rebound and the incidence of acute rejection. We concluded that no treatment is necessary for rebounded antiblood type antibodies. © 2014 Steunstichting ESOT.

  17. Influence of type I IFN signaling on anti-MOG antibody-mediated demyelination

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    Berg, Carsten Tue; Khorooshi, Reza M. H.; Asgari, Nasrin

    2017-01-01

    Background Antibodies with specificity for myelin oligodendrocyte glycoprotein (MOG) are implicated in multiple sclerosis and related diseases. The pathogenic importance of anti-MOG antibody in primary demyelinating pathology remains poorly characterized. Objective The objective of this study...... is to investigate whether administration of anti-MOG antibody would be sufficient for demyelination and to determine if type I interferon (IFN) signaling plays a similar role in anti-MOG antibody-mediated pathology, as has been shown for neuromyelitis optica-like pathology. Methods Purified IgG2a monoclonal anti...... demyelination in wild-type and IFNAR1-KO mice. Conclusions Anti-MOG antibody and complement was sufficient to induce callosal demyelination, and pathology was dependent on type I IFN. Induction of EAE in IFNAR1-KO mice overcame the dependence on type I IFN for anti-MOG and complement-mediated demyelination....

  18. Antibody-mediated immunotherapy against chronic hepatitis B virus infection.

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    Gao, Ying; Zhang, Tian-Ying; Yuan, Quan; Xia, Ning-Shao

    2017-08-03

    The currently available drugs to treat hepatitis B virus (HBV) infection include interferons and nucleos(t)ide analogs, which can only induce disease remission and are inefficient for the functional cure of patients with chronic HBV infection (CHB). Since high titers of circulating hepatitis B surface antigen (HBsAg) may be essential to exhaust the host anti-HBV immune response and they cannot be significantly reduced by current drugs, new antiviral strategies aiming to suppress serum hepatitis B surface antigen (HBsAg) could help restore virus-specific immune responses and promote the eradication of the virus. As an alternative strategy, immunotherapy with HBsAg-specific antibodies has shown some direct HBsAg suppression effects in several preclinical and clinical trial studies. However, most described previously HBsAg-specific antibodies only had very short-term HBsAg suppression effects in CHB patients and animal models mimicking persistent HBV infection. More-potent antibodies with long-lasting HBsAg clearance effects are required for the development of the clinical application of antibody-mediated immunotherapy for CHB treatment. Our recent study described a novel mAb E6F6 that targets a unique epitope on HBsAg. It could durably suppress the levels of HBsAg and HBV DNA via Fcγ receptor-dependent phagocytosis in vivo. In this commentary, we summarize the current research progress, including the therapeutic roles and mechanisms of antibody-mediated HBV clearance as well as the epitope-determined therapeutic potency of the antibody. These insights may provide some clues and guidance to facilitate the development of therapeutic antibodies against persistent viral infection.

  19. Antibody-mediated Prevention of Fusarium Mycotoxins in the Field

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    Yu-Cai Liao

    2008-10-01

    Full Text Available Fusarium mycotoxins directly accumulated in grains during the infection of wheat and other cereal crops by Fusarium head blight (FHB pathogens are detrimental to humans and domesticated animals. Prevention of the mycotoxins via the development of FHB-resistant varieties has been a challenge due to the scarcity of natural resistance against FHB pathogens. Various antibodies specific to Fusarium fungi and mycotoxins are widely used in immunoassays and antibody-mediated resistance in planta against Fusarium pathogens has been demonstrated. Antibodies fused to antifungal proteins have been shown to confer a very significantly enhanced Fusarium resistance in transgenic plants. Thus, antibody fusions hold great promise as an effective tool for the prevention of mycotoxin contaminations in cereal grains. This review highlights the utilization of protective antibodies derived from phage display to increase endogenous resistance of wheat to FHB pathogens and consequently to reduce mycotoxins in field. The role played by Fusarium-specific antibody in the resistance is also discussed.

  20. Torque Teno Virus Load-Inverse Association With Antibody-Mediated Rejection After Kidney Transplantation.

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    Schiemann, Martin; Puchhammer-Stöckl, Elisabeth; Eskandary, Farsad; Kohlbeck, Philip; Rasoul-Rockenschaub, Susanne; Heilos, Andreas; Kozakowski, Nicolas; Görzer, Irene; Kikić, Željko; Herkner, Harald; Böhmig, Georg A; Bond, Gregor

    2017-02-01

    Antibody-mediated rejection (AMR) represents one of the cardinal causes of late allograft loss after kidney transplantation, and there is great need for noninvasive tools improving early diagnosis of this rejection type. One promising strategy might be the quantification of peripheral blood DNA levels of the highly prevalent and apathogenic Torque Teno virus (TTV), which might mirror the overall level of immunosuppression and thus help determine the risk of alloimmune response. To assess the association between TTV load in the peripheral blood and AMR, 715 kidney transplant recipients (median, 6.3 years posttransplantation) were subjected to a systematical cross-sectional AMR screening and, in parallel, TTV quantification. Eighty-six of these recipients had donor-specific antibodies and underwent protocol biopsy, AMR-positive patients (n = 46) showed only 25% of the TTV levels measured in patients without AMR (P = 0.003). In a generalized linear model, higher TTV levels were associated with a decreased risk for AMR after adjustment for potential confounders (risk ratio 0.94 per TTV log level; 95% confidence interval 0.90-0.99; P = 0.02). Future studies will have to clarify whether longitudinal assessment of TTV load might predict AMR risk and help guide the type and intensity of immunosuppression to prevent antibody-mediated graft injury.

  1. Reviewing the pathogenesis of antibody-mediated rejection and renal graft pathology after kidney transplantation.

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    Morozumi, Kunio; Takeda, Asami; Otsuka, Yasuhiro; Horike, Keiji; Gotoh, Norihiko; Narumi, Shunji; Watarai, Yoshihiko; Kobayashi, Takaaki

    2016-07-01

    The clinicopathological context of rejection after kidney transplantation was well recognized. Banff conferences greatly contributed to elucidate the pathogenesis and to establish the pathologic criteria of rejection after kidney transplantation. The most important current problem of renal transplantation is de novo donor-specific antibody (DSA) production leading chronic rejection and graft loss. Microvascular inflammation is considered as a reliable pathological marker for antibody-mediated rejection (AMR) in the presence of DSA. Electron microscopic study allowed us to evaluate early changes in peritubular capillaries in T-lymphocyte mediated rejection and transition to antibody-mediated rejection. Severe endothelial injuries with edema and activated lymphocyte invaded into subendothelial space with early multi-layering of peritubular capillary basement membrane suggest T-lymphocyte mediated rejection induce an unbounded chain of antibody-mediated rejection. The risk factors of AMR after ABO-incompatible kidney transplantation are important issues. Anti-ABO blood type antibody titre of IgG excess 32-fold before transplant operation is the only predictable factor for acute AMR. Characteristics of chronic active antibody-mediated rejection (CAAMR) are one of the most important problems. Light microscopic findings and C4d stain of peritubular capillary and glomerular capillary are useful diagnostic criteria of CAAMR. Microvascular inflammation, double contour of glomerular capillary and thickening of peritubular capillary basement are good predictive factors of the presence of de novo DSA. C4d stain of linear glomerular capillary is a more sensitive marker for CAAMR than positive C4d of peritubular capillary. Early and sensitive diagnostic attempts of diagnosing CAAMR are pivotal to prevent chronic graft failure. © 2016 Asian Pacific Society of Nephrology.

  2. Acute antibody-mediated rejection of skin grafts without involvement of granulocytes or complement

    International Nuclear Information System (INIS)

    Bogman, M.J.; Cornelissen, I.M.; Koene, R.A.

    1984-01-01

    In immunosuppressed mice that carry rat skin xeno-grafts, acute antibody-mediated graft rejection (AAR) can be induced by intravenous administration of mouse anti-rat globulin. Dependent on the amount of antibody injected and on the complement status of the recipient, an Arthus-like or a Shwartzman-like pattern of vasculitis occurs. The role of polymorphonuclear granulocytes (PMNs) in either type of vasculitis was tested by inducing AAR in recipients depleted of PMNs by total body irradiation. Despite the absence of PMNs in the graft vessels, AAR occurred both in the Arthus-like and in the Shwartzman-like type. Moreover, AAR could be elicited in PMN-depleted recipients that were complement-depleted by cobra venom factor treatment or were congenitally C5-deficient. We conclude that neither the PMN nor complement is an essential mediator the PMN nor complement is an essential mediator in this form of antibody-mediated vasculitis

  3. Multifactorial aspects of antibody-mediated blood cell destruction

    NARCIS (Netherlands)

    Kapur, R.

    2014-01-01

    The research described in this thesis focuses on diseases of antibody-mediated blood cell destruction via FcγRs on phagocytes, in particular regarding platelets in fetal or neonatal alloimmune thrombocytopenia (FNAIT) and red blood cells (RBC) in hemolytic disease of the fetus and newborn (HDFN).

  4. Comprehensive Cross-Clade Characterization of Antibody-Mediated Recognition, Complement-Mediated Lysis, and Cell-Mediated Cytotoxicity of HIV-1 Envelope-Specific Antibodies toward Eradication of the HIV-1 Reservoir.

    Science.gov (United States)

    Mujib, Shariq; Liu, Jun; Rahman, A K M Nur-Ur; Schwartz, Jordan A; Bonner, Phil; Yue, Feng Yun; Ostrowski, Mario A

    2017-08-15

    Immunotherapy with passive administration of broadly neutralizing HIV-1 envelope-specific antibodies (bnAbs) in the setting of established infection in vivo has yielded mixed results. The contribution of different antibodies toward the direct elimination of infected cells is poorly understood. In this study, we determined the ability of 12 well-characterized anti-HIV-1 neutralizing antibodies to recognize and eliminate primary CD4 T cells infected with HIV-1 belonging to clades A, B, C, and D, via antibody-dependent complement-mediated lysis (ADCML) and antibody-dependent cell-mediated cytotoxicity (ADCC), in vitro We further tested unique combinations of these antibodies to determine the optimal antibody cocktails to be tested in future clinical trials. We report that antibody binding to infected CD4 T cells is highly variable and correlates with ADCML and ADCC processes. Particularly, antibodies targeting the envelope glycan shield (2G12) and V1/V2 site (PG9, PG16, and PGT145) are best at recognizing HIV-1-infected CD4 T cells. However, only PG9 and PG16 and their combinations with other bnAbs sufficiently induced the elimination of HIV-1-infected CD4 T cells by ADCML, ADCC, or both. Notably, CD4 binding site antibodies VRC01, 3BNC117, and NIH45-46 G54W did not exhibit recognition of infected cells and were unable to induce their killing. Future trials geared toward the development of a cure for HIV/AIDS should incorporate V1/V2 antibodies for maximal clearance of infected cells. With the use of only primary immune cells, we conducted a comprehensive cross-clade physiological analysis to aid the direction of antibodies as therapeutics toward the development of a cure for HIV/AIDS. IMPORTANCE Several antibodies capable of neutralizing the majority of circulating HIV-1 strains have been identified to date and have been shown to prevent infection in animal models. However, the use of combinations of such broadly neutralizing antibodies (bnAbs) for the treatment and

  5. Antibody-Mediated Rejection of the Heart in the Setting of Autoimmune Demyelinating Polyneuropathy: A Case Report and Review of the Literature

    Directory of Open Access Journals (Sweden)

    Kathryn J. Lindley

    2012-01-01

    Full Text Available Background. Antibody-mediated rejection (AMR is caused by the production of donor-specific antibodies (DSA which lead to allograft injury in part via complement activation. The inflammatory demyelinating polyneuropathies (IDP are inflammatory disorders of the nervous system, involving both cellular and humoral immune mechanisms directed against myelin. Case Report. A 58-year-old man five years after heart transplant presented with progressive dyspnea, imbalance, dysphagia, and weakness. Nerve conduction studies and electromyogram were consistent with IDP. Plasmapheresis and high-dose steroids resulted in improvement in neurologic symptoms. Within two weeks, he was readmitted with anasarca and acute renal failure, requiring intravenous furosemide and inotropic support. Echocardiogram and right heart catheterization revealed reduced cardiac function and elevated filling pressures. DSA was positive against HLA DR53, and endomyocardial biopsy revealed grade 1R chronic inflammation, with strong capillary endothelial immunostaining for C4d. Plasmapheresis and intravenous immunoglobulin (IVIG were initiated. His anasarca and renal failure subsequently resolved, echocardiogram showed improved function off inotropes, and anti-DR53 MFI was reduced by 57%. Conclusions. This is an example of a single immune-mediated process causing concurrent IDP and AMR. The improvement in cardiac function and neurologic symptoms with plasmapheresis, IVIG, and high-dose steroids argues for a unifying antibody-mediated mechanism.

  6. Monoclonal antibody fragment removal mediated by mixed mode resins.

    Science.gov (United States)

    O'Connor, Ellen; Aspelund, Matthew; Bartnik, Frank; Berge, Mark; Coughlin, Kelly; Kambarami, Mutsa; Spencer, David; Yan, Huiming; Wang, William

    2017-05-26

    Efforts to increase monoclonal antibody expression in cell culture can result in the presence of fragmented species requiring removal in downstream processing. Capto adhere, HEA Hypercel, and PPA Hypercel anion exchange/hydrophobic interaction mixed mode resins were evaluated for their fragment removal capabilities and found to separate large hinge IgG1 antibody fragment (LHF) from monomer. Removal of greater than 75% of LHF population occurred at pH 8 and low conductivity. The mechanism of fragment removal was investigated in two series of experiments. The first experimental series consisted of comparison to chromatographic behavior on corresponding single mode resins. Both single mode anion exchange and hydrophobic interaction resins failed to separate LHF. The second experimental series studied the impact of phase modifiers, ethylene glycol, urea, and arginine on the mixed mode mediated removal. The addition of ethylene glycol decreased LHF removal by half. Further decreases in LHF separation were seen upon incubation with urea and arginine. Therefore, it was discovered that the purification is the result of a mixed mode phenomena dominated by hydrophobic interaction and hydrogen bonding effects. The site of interaction between the LHF and mixed mode resin was determined by chemical labeling of lysine residues with sulfo-NHS acetate. The labeling identified the antibody hinge and light chain regions as mediating the fragment separation. Sequence analysis showed that under separation conditions, a hydrophobic proline patch and hydrogen bonding serine and threonine residues mediate the hinge interaction with the Capto adhere ligand. Additionally, a case study is presented detailing the optimization of fragment removal using Capto adhere resin to achieve purity and yield targets in a manufacturing facility. This study demonstrated that mixed mode resins can be readily integrated into commercial antibody platform processes when additional chromatographic abilities

  7. Antibody dependent cellular phagocytosis (ADCP) and antibody dependent cellular cytotoxicity (ADCC) of breast cancer cells mediated by bispecific antibody, MDX-210.

    Science.gov (United States)

    Watanabe, M; Wallace, P K; Keler, T; Deo, Y M; Akewanlop, C; Hayes, D F

    1999-02-01

    MDX-210 is a bispecific antibody (BsAb) with specificity for both the proto-oncogene product of HER-2/neu (c-erbB-2) and FcgammaRI (CD64). HER-2/neu is overexpressed in malignant tissue of approximately 30% of patients with breast cancer, and FcgammaRI is expressed on human monocytes, macrophages, and IFN-gamma activated granulocytes. We investigated phagocytosis and cytolysis of cultured human breast cancer cells by human monocyte-derived macrophages (MDM) mediated by BsAb MDX-210, its partially humanized derivative (MDX-H210), and its parent MoAb 520C9 (anti-HER-2/neu) under various conditions. Purified monocytes were cultured with GM-CSF, M-CSF, or no cytokine for five or six days. Antibody dependent cellular phagocytosis (ADCP) and cytolysis (ADCC) assays were performed with the MDM and HER-2/neu positive target cells (SK-BR-3). ADCP was measured by two-color fluorescence flow cytometry using PKH2 (green fluorescent dye) and phycoerythrin-conjugated (red) monoclonal antibodies (MoAb) against human CD14 and CD11b. ADCC was measured with a non-radioactive LDH detection kit. Both BsAb MDX-210 (via FcgammaRI) and MoAb 520C9 (mouse IgG1, via FcgammaRII) mediated similar levels of ADCP and ADCC. ADCP mediated by BsAb MDX-H210 was identical to that mediated by BsAb MDX-210. Confocal microscopy demonstrated that dual-labeled cells represented true phagocytosis. Both ADCP and ADCC were higher when MDM were pre-incubated with GM-CSF than when incubated with M-CSF. BsAb MDX-210 is as active in vitro as the parent MoAb 520C9 in inducing both phagocytosis and cytolysis of MDM. MDX-210 and its partially humanized derivative, MDX-H210, mediated similar levels of ADCP. GM-CSF appears to superior to M-CSF in inducing MDM-mediated ADCC and ADCP. These studies support the ongoing clinical investigations of BsAb MDX-210 and its partially humanized derivative.

  8. Acute antibody-mediated rejection in pancreas and kidney transplantation

    NARCIS (Netherlands)

    Kort, Hanneke de

    2013-01-01

    In this thesis, acute rejection after kidney, simultaneous pancreas and kidney (SPKT), and islets of Langerhans transplantation was addressed. The focus is on acute antibody-mediated rejection (AMR) after transplantation and on a potential strategy using cellular immune modulation to prevent acute

  9. Complement-fixing antibodies against denatured HLA and MICA antigens are associated with antibody mediated rejection.

    Science.gov (United States)

    Cai, Junchao; Terasaki, Paul I; Zhu, Dong; Lachmann, Nils; Schönemann, Constanze; Everly, Matthew J; Qing, Xin

    2016-02-01

    We have found antibodies against denatured HLA class I antigens in the serum of allograft recipients which were not significantly associated with graft failure. It is unknown whether transplant recipients also have denatured HLA class II and MICA antibodies. The effects of denatured HLA class I, class II, and MICA antibodies on long-term graft outcome were further investigated based on their ability to fix complement c1q. In this 4-year retrospective cohort study, post-transplant sera from 975 kidney transplant recipients were tested for antibodies against denatured HLA/MICA antigens and these antibodies were further classified based on their ability to fix c1q. Thirty percent of patients had antibodies against denatured HLA class I, II, or MICA antigens. Among them, 8.5% and 21.5% of all patients had c1q-fixing and non c1q-fixing antibodies respectively. There was no significant difference on graft survival between patients with or without antibodies against denatured HLA/MICA. However, when these antibodies were further classified according to their ability to fix c1q, patients with c1q-fixing antibodies had a significantly lower graft survival rate than patients without antibodies or patients with non c1q-fixing antibodies (p=0.008). In 169 patients who lost renal grafts, 44% of them had c1q-fixing antibodies against denatured HLA/MICA antigens, which was significantly higher than that in patients with functioning renal transplants (25%, pantibodies were more significantly associated with graft failure caused by AMR (72.73%) or mixed AMR/CMR (61.9%) as compared to failure due to CMR (35.3%) or other causes (39.2%) (p=0.026). Transplant recipients had antibodies against denatured HLA class I, II, and MICA antigens. However, only c1q-fixing antibodies were associated with graft failure which was related to antibody mediated rejection. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Late antibody-mediated rejection after ABO-incompatible kidney transplantation during Gram-negative sepsis

    NARCIS (Netherlands)

    A. de Weerd (Annelies); A.G. Vonk (Alieke); H. van der Hoek (Hans); M. van Groningen (Marian); W. Weimar (Willem); M.G.H. Betjes (Michiel); M. Agteren (Madelon)

    2014-01-01

    textabstractBackground: The major challenge in ABO-incompatible transplantation is to minimize antibody-mediated rejection. Effective reduction of the anti-ABO blood group antibodies at the time of transplantation has made ABO-incompatible kidney transplantation a growing practice in our hospital

  11. Antibody-mediated delivery of interleukin 4 to the neo-vasculature reduces chronic skin inflammation

    OpenAIRE

    Hemmerle Teresa; Zgraggen Silvana; Matasci Mattia; Halin Cornelia; Detmar Michael; Neri Dario

    2014-01-01

    BACKGROUND: The antibody mediated delivery of cytokines (quot;immunocytokinesquot;) to sites of pathological angiogenesis represents an attractive strategy for the development of innovative biopharmaceuticals capable of modulating the activity of the immune system in cancer and in chronic inflammatory conditions. OBJECTIVE: Recombinant IL4 has previously been shown to be therapeutically active in patients with psoriasis. The antibody mediated delivery of this cytokine to sites of chronic skin...

  12. Novel Non-Histocompatibility Antigen Mismatched Variants Improve the Ability to Predict Antibody-Mediated Rejection Risk in Kidney Transplant

    Directory of Open Access Journals (Sweden)

    Silvia Pineda

    2017-12-01

    Full Text Available Transplant rejection is the critical clinical end-point limiting indefinite survival after histocompatibility antigen (HLA mismatched organ transplantation. The predominant cause of late graft loss is antibody-mediated rejection (AMR, a process whereby injury to the organ is caused by donor-specific antibodies, which bind to HLA and non-HLA (nHLA antigens. AMR is incompletely diagnosed as donor/recipient (D/R matching is only limited to the HLA locus and critical nHLA immunogenic antigens remain to be identified. We have developed an integrative computational approach leveraging D/R exome sequencing and gene expression to predict clinical post-transplant outcome. We performed a rigorous statistical analysis of 28 highly annotated D/R kidney transplant pairs with biopsy-confirmed clinical outcomes of rejection [either AMR or T-cell-mediated rejection (CMR] and no-rejection (NoRej, identifying a significantly higher number of mismatched nHLA variants in AMR (ANOVA—p-value = 0.02. Using Fisher’s exact test, we identified 123 variants associated mainly with risk of AMR (p-value < 0.001. In addition, we applied a machine-learning technique to circumvent the issue of statistical power and we found a subset of 65 variants using random forest, that are predictive of post-tx AMR showing a very low error rate. These variants are functionally relevant to the rejection process in the kidney and AMR as they relate to genes and/or expression quantitative trait loci (eQTLs that are enriched in genes expressed in kidney and vascular endothelium and underlie the immunobiology of graft rejection. In addition to current D/R HLA mismatch evaluation, additional mismatch nHLA D/R variants will enhance the stratification of post-tx AMR risk even before engraftment of the organ. This innovative study design is applicable in all solid organ transplants, where the impact of mitigating AMR on graft survival may be greater, with considerable benefits on

  13. Vaccine induced antibodies to the first variable loop of human immunodeficiency virus type 1 gp120, mediate antibody-dependent virus inhibition in macaques.

    Science.gov (United States)

    Bialuk, Izabela; Whitney, Stephen; Andresen, Vibeke; Florese, Ruth H; Nacsa, Janos; Cecchinato, Valentina; Valeri, Valerio W; Heraud, Jean-Michel; Gordon, Shari; Parks, Robyn Washington; Montefiori, David C; Venzon, David; Demberg, Thorsten; Guroff, Marjorie Robert-; Landucci, Gary; Forthal, Donald N; Franchini, Genoveffa

    2011-12-09

    The role of antibodies directed against the hyper variable envelope region V1 of human immunodeficiency virus type 1 (HIV-1), has not been thoroughly studied. We show that a vaccine able to elicit strain-specific non-neutralizing antibodies to this region of gp120 is associated with control of highly pathogenic chimeric SHIV(89.6P) replication in rhesus macaques. The vaccinated animal that had the highest titers of antibodies to the amino terminus portion of V1, prior to challenge, had secondary antibody responses that mediated cell killing by antibody-dependent cellular cytotoxicity (ADCC), as early as 2 weeks after infection and inhibited viral replication by antibody-dependent cell-mediated virus inhibition (ADCVI), by 4 weeks after infection. There was a significant inverse correlation between virus level and binding antibody titers to the envelope protein, (R=-0.83, p=0.015), and ADCVI (R=-0.84 p=0.044). Genotyping of plasma virus demonstrated in vivo selection of three SHIV(89.6P) variants with changes in potential N-linked glycosylation sites in V1. We found a significant inverse correlation between virus levels and titers of antibodies that mediated ADCVI against all the identified V1 virus variants. A significant inverse correlation was also found between neutralizing antibody titers to SHIV(89.6) and virus levels (R=-0.72 p=0.0050). However, passive inoculation of purified immunoglobulin from animal M316, the macaque that best controlled virus, to a naïve macaque, resulted in a low serum neutralizing antibodies and low ADCVI activity that failed to protect from SHIV(89.6P) challenge. Collectively, while our data suggest that anti-envelope antibodies with neutralizing and non-neutralizing Fc(R-dependent activities may be important in the control of SHIV replication, they also demonstrate that low levels of these antibodies alone are not sufficient to protect from infection. Published by Elsevier Ltd.

  14. Diversification of the Primary Antibody Repertoire by AID-Mediated Gene Conversion.

    Science.gov (United States)

    Lanning, Dennis K; Knight, Katherine L

    2015-01-01

    Gene conversion, mediated by activation-induced cytidine deaminase (AID), has been found to contribute to generation of the primary antibody repertoire in several vertebrate species. Generation of the primary antibody repertoire by gene conversion of immunoglobulin (Ig) genes occurs primarily in gut-associated lymphoid tissues (GALT) and is best described in chicken and rabbit. Here, we discuss current knowledge of the mechanism of gene conversion as well as the contribution of the microbiota in promoting gene conversion of Ig genes. Finally, we propose that the antibody diversification strategy used in GALT species, such as chicken and rabbit, is conserved in a subset of human and mouse B cells.

  15. Cre-mediated cell ablation contests mast cell contribution in models of antibody- and T cell-mediated autoimmunity.

    Science.gov (United States)

    Feyerabend, Thorsten B; Weiser, Anne; Tietz, Annette; Stassen, Michael; Harris, Nicola; Kopf, Manfred; Radermacher, Peter; Möller, Peter; Benoist, Christophe; Mathis, Diane; Fehling, Hans Jörg; Rodewald, Hans-Reimer

    2011-11-23

    Immunological functions of mast cells remain poorly understood. Studies in Kit mutant mice suggest key roles for mast cells in certain antibody- and T cell-mediated autoimmune diseases. However, Kit mutations affect multiple cell types of both immune and nonimmune origin. Here, we show that targeted insertion of Cre-recombinase into the mast cell carboxypeptidase A3 locus deleted mast cells in connective and mucosal tissues by a genotoxic Trp53-dependent mechanism. Cre-mediated mast cell eradication (Cre-Master) mice had, with the exception of a lack of mast cells and reduced basophils, a normal immune system. Cre-Master mice were refractory to IgE-mediated anaphylaxis, and this defect was rescued by mast cell reconstitution. This mast cell-deficient strain was fully susceptible to antibody-induced autoimmune arthritis and to experimental autoimmune encephalomyelitis. Differences comparing Kit mutant mast cell deficiency models to selectively mast cell-deficient mice call for a systematic re-evaluation of immunological functions of mast cells beyond allergy. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Studies on ADCC (antibody-dependent cell-mediated cytotoxicity) using sheep red blood cells as target cells, 2

    International Nuclear Information System (INIS)

    Ichikawa, Yukinobu; Takaya, Masatoshi; Arimori, Shigeru

    1979-01-01

    A non-specific cytotoxic mediator from effector cells (human peripheral blood leukocytes) was investigated in the ADCC (antibody-dependent cell-mediated cytotoxicity) system using antibody-coated sheep red blood cells (SRBC) as target cells. 51 Cr-labelled homologous (sheep) or heterologous (human) red blood cells were used as adjacent cells. Either crude lymphocyte fraction, phagocyte depleted fraction or granulocyte rich fraction separated from human peripheral leukocytes showed moderate cytotoxic effect on homologous adjacent cells, however no cytotoxic activity on heterologous adjacent cells was demonstrated in any leukocyte fraction. This suggests that the cytotoxic effects on homologous adjacent cells were resulted from the translocation of antibody molecules to adjacent cells from antibody-coated target cells. We concluded that the cytotoxic mechanism in this ADCC system was not mediated by non-specific soluble factors released from either human peripheral lymphocytes, monocytes or granulocytes. (author)

  17. Long-term experience of plasmapheresis in antibody-mediated rejection in renal transplantation.

    LENUS (Irish Health Repository)

    Brown, C M

    2009-11-01

    Antibody-mediated rejection (AMR) continues to pose a serious challenge in renal transplantation with potentially devastating consequences. Treatment options for this condition include plasmapheresis, high-dose intravenous immunoglobulin (IVIG), plasmapheresis with low-dose IVIG, and the use of rituximab (anti-CD20 chimeric antibody). We previously reported on the short-term outcome of plasmapheresis as a rescue therapy for AMR in our centre. We now report on the long-term follow up.

  18. Sialyl-Tn vaccine induces antibody-mediated tumour protection in a relevant murine model

    DEFF Research Database (Denmark)

    Julien, S; Picco, G; Sewell, R

    2009-01-01

    challenge. We show that synthetic STn coupled to keyhole limpet haemocyanin (Theratope), induced antibodies to STn that recognised the glycan carried on a number of glycoproteins and in these mice a significant delay in tumour growth was observed. The protection was dependent on STn being expressed...... by the tumour and was antibody mediated. Affinity chromatography of the STn-expressing tumour cell line, followed by mass spectrometry, identified osteopontin as a novel STn-carrying glycoprotein which was highly expressed by the tumours. These results suggest that if antibodies can be induced to a number...

  19. Ibrutinib interferes with the cell-mediated anti-tumor activities of therapeutic CD20 antibodies: implications for combination therapy

    DEFF Research Database (Denmark)

    Da Roit, F.; Engelberts, P. J.; Taylor, R. P.

    2015-01-01

    The novel Bruton tyrosine kinase inhibitor ibrutinib and phosphatidyl-4-5-biphosphate 3-kinase-delta inhibitor idelalisib are promising drugs for the treatment of chronic lymphocytic leukemia and B-cell non-Hodgkin lymphoma, either alone or in combination with anti-CD20 antibodies. We investigated...... the possible positive or negative impact of these drugs on all known mechanisms of action of both type I and type II anti-CD20 antibodies. Pretreatment with ibrutinib for 1 hour did not increase direct cell death of cell lines or chronic lymphocytic leukemia samples mediated by anti-CD20 antibodies. Pre......-treatment with ibrutinib did not inhibit complement activation or complement-mediated lysis. In contrast, ibrutinib strongly inhibited all cell-mediated mechanisms induced by anti-CD20 antibodies rituximab, ofatumumab or obinutuzumab, either in purified systems or whole blood assays. Activation of natural killer cells...

  20. Enhanced killing of chordoma cells by antibody-dependent cell-mediated cytotoxicity employing the novel anti-PD-L1 antibody avelumab

    OpenAIRE

    Fujii, Rika; Friedman, Eitan R.; Richards, Jacob; Tsang, Kwong Y.; Heery, Christopher R.; Schlom, Jeffrey; Hodge, James W.

    2016-01-01

    Chordoma, a rare bone tumor derived from the notochord, has been shown to be resistant to conventional therapies. Checkpoint inhibition has shown great promise in immune-mediated therapy of diverse cancers. The anti-PD-L1 mAb avelumab is unique among checkpoint inhibitors in that it is a fully human IgG1 capable of mediating antibody-dependent cell-mediated cytotoxicity (ADCC) of PD-L1-expressing tumor cells. Here, we investigated avelumab as a potential therapy for chordoma. We examined 4 ch...

  1. Ibrutinib interferes with the cell-mediated anti-tumor activities of therapeutic CD20 antibodies: implications for combination therapy

    Science.gov (United States)

    Roit, Fabio Da; Engelberts, Patrick J.; Taylor, Ronald P.; Breij, Esther C.W.; Gritti, Giuseppe; Rambaldi, Alessandro; Introna, Martino; Parren, Paul W.H.I.; Beurskens, Frank J.; Golay, Josée

    2015-01-01

    The novel Bruton tyrosine kinase inhibitor ibrutinib and phosphatidyl-4-5-biphosphate 3-kinase-δ inhibitor idelalisib are promising drugs for the treatment of chronic lymphocytic leukemia and B-cell non-Hodgkin lymphoma, either alone or in combination with anti-CD20 antibodies. We investigated the possible positive or negative impact of these drugs on all known mechanisms of action of both type I and type II anti-CD20 antibodies. Pretreatment with ibrutinib for 1 hour did not increase direct cell death of cell lines or chronic lymphocytic leukemia samples mediated by anti-CD20 antibodies. Pre-treatment with ibrutinib did not inhibit complement activation or complement-mediated lysis. In contrast, ibrutinib strongly inhibited all cell-mediated mechanisms induced by anti-CD20 antibodies rituximab, ofatumumab or obinutuzumab, either in purified systems or whole blood assays. Activation of natural killer cells, and antibody-dependent cellular cytotoxicity by these cells, as well as phagocytosis by macrophages or neutrophils were inhibited by ibrutinib with a half maximal effective concentration of 0.3–3 μM. Analysis of anti-CD20 mediated activation of natural killer cells isolated from patients on continued oral ibrutinib treatment suggested that repeated drug dosing inhibits these cells in vivo. Finally we show that the phosphatidyl-4-5-biphosphate 3-kinase-δ inhibitor idelalisib similarly inhibited the immune cell-mediated mechanisms induced by anti-CD20 antibodies, although the effects of this drug at 10 μM were weaker than those observed with ibrutinib at the same concentration. We conclude that the design of combined treatment schedules of anti-CD20 antibodies with these kinase inhibitors should consider the multiple negative interactions between these two classes of drugs. PMID:25344523

  2. Enhancement of antibody-dependent cell-mediated cytotoxicity by endowing IgG with FcαRI (CD89) binding.

    Science.gov (United States)

    Borrok, M Jack; Luheshi, Nadia M; Beyaz, Nurten; Davies, Gareth C; Legg, James W; Wu, Herren; Dall'Acqua, William F; Tsui, Ping

    2015-01-01

    Fc effector functions such as antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cell-mediated phagocytosis (ADCP) are crucial to the efficacy of many antibody therapeutics. In addition to IgG, antibodies of the IgA isotype can also promote cell killing through engagement of myeloid lineage cells via interactions between the IgA-Fc and FcαRI (CD89). Herein, we describe a unique, tandem IgG1/IgA2 antibody format in the context of a trastuzumab variable domain that exhibits enhanced ADCC and ADCP capabilities. The IgG1/IgA2 tandem Fc format retains IgG1 FcγR binding as well as FcRn-mediated serum persistence, yet is augmented with myeloid cell-mediated effector functions via FcαRI/IgA Fc interactions. In this work, we demonstrate anti-human epidermal growth factor receptor-2 antibodies with the unique tandem IgG1/IgA2 Fc can better recruit and engage cytotoxic polymorphonuclear (PMN) cells than either the parental IgG1 or IgA2. Pharmacokinetics of IgG1/IgA2 in BALB/c mice are similar to the parental IgG, and far surpass the poor serum persistence of IgA2. The IgG1/IgA2 format is expressed at similar levels and with similar thermal stability to IgG1, and can be purified via standard protein A chromatography. The tandem IgG1/IgA2 format could potentially augment IgG-based immunotherapeutics with enhanced PMN-mediated cytotoxicity while avoiding many of the problems associated with developing IgAs.

  3. Current and future challenges in therapy for antibody-mediated rejection.

    Science.gov (United States)

    Nair, Nandini; Ball, Timothy; Uber, Patricia A; Mehra, Mandeep R

    2011-06-01

    Antibody-mediated rejection (AMR) continues to present a challenge for the survival of the cardiac allograft. AMR appears to be on the rise, likely secondary to changing trends in clinical practice, including selection of patients for transplantation on mechanical circulatory support and development of more effective combinations of immunosuppressive drugs against acute cellular rejection. Most current strategies are aimed at treating acute AMR, but the treatment of chronic AMR is still not well defined. Clinically, AMR can often be more severe than cellular rejection and more difficult to treat, often not responding to typical protocols of increased immunosuppression. Complex steps involved in the antibody response allows for several potential targets for therapeutic intervention, including suppression of T and B cells, elimination of circulating antibodies, and inhibition of residual antibodies. Existing evidence suggests a multiregimen approach is the best option. Sustenance of accommodation and induction of tolerance could be viewed as viable options if adequate immune surveillance can be achieved in this setting. This review discusses the challenges in treating AMR and provides a critical analysis of current and possible future therapies. Copyright © 2011 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  4. The Rac Activator DOCK2 Mediates Plasma Cell Differentiation and IgG Antibody Production.

    Science.gov (United States)

    Ushijima, Miho; Uruno, Takehito; Nishikimi, Akihiko; Sanematsu, Fumiyuki; Kamikaseda, Yasuhisa; Kunimura, Kazufumi; Sakata, Daiji; Okada, Takaharu; Fukui, Yoshinori

    2018-01-01

    A hallmark of humoral immune responses is the production of antibodies. This process involves a complex cascade of molecular and cellular interactions, including recognition of specific antigen by the B cell receptor (BCR), which triggers activation of B cells and differentiation into plasma cells (PCs). Although activation of the small GTPase Rac has been implicated in BCR-mediated antigen recognition, its precise role in humoral immunity and the upstream regulator remain elusive. DOCK2 is a Rac-specific guanine nucleotide exchange factor predominantly expressed in hematopoietic cells. We found that BCR-mediated Rac activation was almost completely lost in DOCK2-deficient B cells, resulting in defects in B cell spreading over the target cell-membrane and sustained growth of BCR microclusters at the interface. When wild-type B cells were stimulated in vitro with anti-IgM F(ab') 2 antibody in the presence of IL-4 and IL-5, they differentiated efficiently into PCs. However, BCR-mediated PC differentiation was severely impaired in the case of DOCK2-deficient B cells. Similar results were obtained in vivo when DOCK2-deficient B cells expressing a defined BCR specificity were adoptively transferred into mice and challenged with the cognate antigen. In addition, by generating the conditional knockout mice, we found that DOCK2 expression in B-cell lineage is required to mount antigen-specific IgG antibody. These results highlight important role of the DOCK2-Rac axis in PC differentiation and IgG antibody responses.

  5. Targeting of indium 111-labeled bivalent hapten to human melanoma mediated by bispecific monoclonal antibody conjugates: Imaging of tumors hosted in nude mice

    International Nuclear Information System (INIS)

    Le Doussal, J.M.; Gruaz-Guyon, A.; Martin, M.; Gautherot, E.; Delaage, M.; Barbet, J.

    1990-01-01

    Antibody conjugates were prepared by coupling F(ab')2 or Fab' fragments of an antibody specific for the human high molecular weight-melanoma associated antigen to Fab' fragments of an antibody specific for indium-diethylenetriaminepentaacetate complexes. Monovalent and bivalent haptens were synthesized by reacting the dipeptide tyrosyl-lysine with diethylenetriaminepentaacetic cyclic anhydride. In vitro, the antibody conjugate mediated binding of the 111In-labeled haptens to melanoma cells. In vivo, it allowed specific localization of the haptens in A375 tumors. The bivalent hapten exhibited much higher efficiency at targeting 111In onto cells, both in vitro and in vivo. Antibody conjugate and hapten doses (2 micrograms and 1 pmol, respectively) and the delay between antibody conjugate and tracer injections (24 h) were adjusted to maximize tumor uptake (4% injected dose/g) and tumor to normal tissue contrast (greater than 3) obtained 3 h after injection of the 111In-labeled bivalent hapten. This two-step technique, when compared to direct targeting of 111In-labeled F(ab')2 fragments, provided lower localization of injected activity into the tumor (x 0.25), but higher tumor/tissue ratios, especially with respect to liver (x 7), spleen (x 8), and kidneys (x 10). In addition, high contrast images were obtained within 3 hours, instead of days. Thus, antibody conjugate-mediated targeting of small bivalent haptens, labeled with short half-life isotopes, is proposed as a general method for improving tumor radioimmunolocalization

  6. Immediate and Catastrophic Antibody-Mediated Rejection in a Lung Transplant Recipient With Anti-Angiotensin II Receptor Type 1 and Anti-Endothelin-1 Receptor Type A Antibodies.

    Science.gov (United States)

    Cozzi, E; Calabrese, F; Schiavon, M; Feltracco, P; Seveso, M; Carollo, C; Loy, M; Cardillo, M; Rea, F

    2017-02-01

    Preexisting donor-specific anti-HLA antibodies (DSAs) have been associated with reduced survival of lung allografts. However, antibodies with specificities other than HLA may have a detrimental role on the lung transplant outcome. A young man with cystic fibrosis underwent lung transplantation with organs from a suitable deceased donor. At the time of transplantation, there were no anti-HLA DSAs. During surgery, the patient developed a severe and intractable pulmonary hypertension associated with right ventriular dysfunction, which required arteriovenous extracorporeal membrane oxygenation. After a brief period of clinical improvement, a rapid deterioration in hemodynamics led to the patient's death on postoperative day 5. Postmortem studies showed that lung specimens taken at the end of surgery were compatible with antibody-mediated rejection (AMR), while terminal samples evidenced diffuse capillaritis, blood extravasation, edema, and microthrombi, with foci of acute cellular rejection (A3). Immunological investigations demonstrated the presence of preexisting antibodies against the endothelin-1 receptor type A (ET A R) and the angiotensin II receptor type 1 (AT 1 R), two of the most potent vasoconstrictors reported to date, whose levels slightly rose after transplantation. These data suggest that preexisting anti-ET A R and anti-AT 1 R antibodies may have contributed to the onset of AMR and to the catastrophic clinical course of this patient. © Copyright 2016 The American Society of Transplantation and the American Society of Transplant Surgeons.

  7. Removal of a C-terminal serine residue proximal to the inter-chain disulfide bond of a human IgG1 lambda light chain mediates enhanced antibody stability and antibody dependent cell-mediated cytotoxicity

    Science.gov (United States)

    Shen, Yang; Zeng, Lin; Zhu, Aiping; Blanc, Tim; Patel, Dipa; Pennello, Anthony; Bari, Amtul; Ng, Stanley; Persaud, Kris; Kang, Yun (Kenneth); Balderes, Paul; Surguladze, David; Hindi, Sagit; Zhou, Qinwei; Ludwig, Dale L.; Snavely, Marshall

    2013-01-01

    Optimization of biophysical properties is a critical success factor for the developability of monoclonal antibodies with potential therapeutic applications. The inter-domain disulfide bond between light chain (Lc) and heavy chain (Hc) in human IgG1 lends structural support for antibody scaffold stability, optimal antigen binding, and normal Fc function. Recently, human IgG1λ has been suggested to exhibit significantly greater susceptibility to reduction of the inter Lc-Hc disulfide bond relative to the same disulfide bond in human IgG1κ. To understand the molecular basis for this observed difference in stability, the sequence and structure of human IgG1λ and human IgG1κ were compared. Based on this Lc comparison, three single mutations were made in the λ Lc proximal to the cysteine residue, which forms a disulfide bond with the Hc. We determined that deletion of S214 (dS) improved resistance of the association between Lc and Hc to thermal stress. In addition, deletion of this terminal serine from the Lc of IgG1λ provided further benefit, including an increase in stability at elevated pH, increased yield from transient transfection, and improved in vitro antibody dependent cell-mediated cytotoxicity (ADCC). These observations support the conclusion that the presence of the terminal serine of the λ Lc creates a weaker inter-chain disulfide bond between the Lc and Hc, leading to slightly reduced stability and a potential compromise in IgG1λ function. Our data from a human IgG1λ provide a basis for further investigation of the effects of deleting terminal serine from λLc on the stability and function of other human IgG1λ antibodies. PMID:23567210

  8. The Rac Activator DOCK2 Mediates Plasma Cell Differentiation and IgG Antibody Production

    Directory of Open Access Journals (Sweden)

    Miho Ushijima

    2018-02-01

    Full Text Available A hallmark of humoral immune responses is the production of antibodies. This process involves a complex cascade of molecular and cellular interactions, including recognition of specific antigen by the B cell receptor (BCR, which triggers activation of B cells and differentiation into plasma cells (PCs. Although activation of the small GTPase Rac has been implicated in BCR-mediated antigen recognition, its precise role in humoral immunity and the upstream regulator remain elusive. DOCK2 is a Rac-specific guanine nucleotide exchange factor predominantly expressed in hematopoietic cells. We found that BCR-mediated Rac activation was almost completely lost in DOCK2-deficient B cells, resulting in defects in B cell spreading over the target cell-membrane and sustained growth of BCR microclusters at the interface. When wild-type B cells were stimulated in vitro with anti-IgM F(ab′2 antibody in the presence of IL-4 and IL-5, they differentiated efficiently into PCs. However, BCR-mediated PC differentiation was severely impaired in the case of DOCK2-deficient B cells. Similar results were obtained in vivo when DOCK2-deficient B cells expressing a defined BCR specificity were adoptively transferred into mice and challenged with the cognate antigen. In addition, by generating the conditional knockout mice, we found that DOCK2 expression in B-cell lineage is required to mount antigen-specific IgG antibody. These results highlight important role of the DOCK2–Rac axis in PC differentiation and IgG antibody responses.

  9. HER2 monoclonal antibodies that do not interfere with receptor heterodimerization-mediated signaling induce effective internalization and represent valuable components for rational antibody-drug conjugate design.

    Science.gov (United States)

    de Goeij, Bart E C G; Peipp, Matthias; de Haij, Simone; van den Brink, Edward N; Kellner, Christian; Riedl, Thilo; de Jong, Rob; Vink, Tom; Strumane, Kristin; Bleeker, Wim K; Parren, Paul W H I

    2014-01-01

    The human epidermal growth factor receptor (HER)2 provides an excellent target for selective delivery of cytotoxic drugs to tumor cells by antibody-drug conjugates (ADC) as has been clinically validated by ado-trastuzumab emtansine (Kadcyla(TM)). While selecting a suitable antibody for an ADC approach often takes specificity and efficient antibody-target complex internalization into account, the characteristics of the optimal antibody candidate remain poorly understood. We studied a large panel of human HER2 antibodies to identify the characteristics that make them most suitable for an ADC approach. As a model toxin, amenable to in vitro high-throughput screening, we employed Pseudomonas exotoxin A (ETA') fused to an anti-kappa light chain domain antibody. Cytotoxicity induced by HER2 antibodies, which were thus non-covalently linked to ETA', was assessed for high and low HER2 expressing tumor cell lines and correlated with internalization and downmodulation of HER2 antibody-target complexes. Our results demonstrate that HER2 antibodies that do not inhibit heterodimerization of HER2 with related ErbB receptors internalize more efficiently and show greater ETA'-mediated cytotoxicity than antibodies that do inhibit such heterodimerization. Moreover, stimulation with ErbB ligand significantly enhanced ADC-mediated tumor kill by antibodies that do not inhibit HER2 heterodimerization. This suggests that the formation of HER2/ErbB-heterodimers enhances ADC internalization and subsequent killing of tumor cells. Our study indicates that selecting HER2 ADCs that allow piggybacking of HER2 onto other ErbB receptors provides an attractive strategy for increasing ADC delivery and tumor cell killing capacity to both high and low HER2 expressing tumor cells.

  10. HIV-1-Specific IgA Monoclonal Antibodies from an HIV-1 Vaccinee Mediate Galactosylceramide Blocking and Phagocytosis

    Science.gov (United States)

    2018-01-01

    ABSTRACT Vaccine-elicited humoral immune responses comprise an array of antibody forms and specificities, with only a fraction contributing to protective host immunity. Elucidation of antibody effector functions responsible for protective immunity against human immunodeficiency virus type 1 (HIV-1) acquisition is a major goal for the HIV-1 vaccine field. Immunoglobulin A (IgA) is an important part of the host defense against pathogens; however, little is known about the role of vaccine-elicited IgA and its capacity to mediate antiviral functions. To identify the antiviral functions of HIV-1-specific IgA elicited by vaccination, we cloned HIV-1 envelope-specific IgA monoclonal antibodies (MAbs) by memory B cell cultures from peripheral blood mononuclear cells from an RV144 vaccinee and produced two IgA clonal cell lines (HG129 and HG130) producing native, nonrecombinant IgA MAbs. The HG129 and HG130 MAbs mediated phagocytosis by monocytes, and HG129 blocked HIV-1 Env glycoprotein binding to galactosylceramide, an alternative HIV-1 receptor. These findings elucidate potential antiviral functions of vaccine-elicited HIV-1 envelope-specific IgA that may act to block HIV-1 acquisition at the portal of entry by preventing HIV-1 binding to galactosylceramide and mediating antibody Fc receptor-mediated virion phagocytosis. Furthermore, these findings highlight the complex and diverse interactions of vaccine-elicited IgA with pathogens that depend on IgA fine specificity and form (e.g., multimeric or monomeric) in the systemic circulation and mucosal compartments. IMPORTANCE Host-pathogen interactions in vivo involve numerous immune mechanisms that can lead to pathogen clearance. Understanding the nature of antiviral immune mechanisms can inform the design of efficacious HIV-1 vaccine strategies. Evidence suggests that both neutralizing and nonneutralizing antibodies can mediate some protection against HIV in animal models. Although numerous studies have characterized the

  11. Factors Predicting Risk for Antibody-mediated Rejection and Graft Loss in Highly Human Leukocyte Antigen Sensitized Patients Transplanted After Desensitization.

    Science.gov (United States)

    Vo, Ashley A; Sinha, Aditi; Haas, Mark; Choi, Jua; Mirocha, James; Kahwaji, Joseph; Peng, Alice; Villicana, Rafael; Jordan, Stanley C

    2015-07-01

    Desensitization with intravenous immunoglobulin and rituximab (I+R) significantly improves transplant rates in highly sensitized patients, but antibody-mediated rejection (ABMR) remains a concern. Between July 2006 and December 2012, 226 highly sensitized patients received transplants after desensitization. Most received alemtuzumab induction and standard immunosuppression. Two groups were examined: ABMR (n = 181) and ABMR (n = 45, 20%). Risk factors for ABMR, pathology, and outcomes were assessed. Significant risks for ABMR included previous transplants and pregnancies as sensitizing events, donor-specific antibody (DSA) relative intensity scores greater than 17, presence of both class I and II DSAs at transplant and time on waitlist. The ABMR showed a significant benefit for graft survival and glomerular filtration rate at 5 years (P desensitized with I+R who remain ABMR have long-term graft and patient survival. The ABMR patients have significantly reduced graft survival and glomerular filtration rate at 5 years, especially TMA. Severe ABMR episodes benefit from treatment with PLEX + Eculizumab. The DSA-relative intensity scores at transplant was a strong predictor of ABMR. Donor-specific antibody avoidance and reduction strategies before transplantation are critical to avoiding ABMR and improving long-term outcomes.

  12. Trastuzumab mediates antibody-dependent cell-mediated cytotoxicity and phagocytosis to the same extent in both adjuvant and metastatic HER2/neu breast cancer patients.

    Science.gov (United States)

    Petricevic, Branka; Laengle, Johannes; Singer, Josef; Sachet, Monika; Fazekas, Judit; Steger, Guenther; Bartsch, Rupert; Jensen-Jarolim, Erika; Bergmann, Michael

    2013-12-12

    Monoclonal antibodies (mAb), such as trastuzumab are a valuable addition to breast cancer therapy. Data obtained from neoadjuvant settings revealed that antibody-dependent cell-mediated cytotoxicity (ADCC) is a major mechanism of action for the mAb trastuzumab. Conflicting results still call into question whether disease progression, prolonged treatment or concomitant chemotherapy influences ADCC and related immunological phenomena. We analyzed the activity of ADCC and antibody-dependent cell-mediated phagocytosis (ADCP) of peripheral blood mononuclear cells (PBMCs) from human epidermal growth factor receptor 2 (HER2/neu) positive breast cancer patients receiving trastuzumab therapy either in an adjuvant (n = 13) or metastatic (n = 15) setting as well as from trastuzumab treatment-naive (t-naive) HER2/neu negative patients (n = 15). PBMCs from healthy volunteers (n = 24) were used as controls. ADCC and ADCP activity was correlated with the expression of antibody binding Fc-gamma receptor (FcγR)I (CD64), FcγRII (CD32) and FcγRIII (CD16) on CD14+ (monocytes) and CD56+ (NK) cells, as well as the expression of CD107a+ (LAMP-1) on CD56+ cells and the total amount of CD4+CD25+FOXP3+ (Treg) cells. In metastatic patients, markers were correlated with progression-free survival (PFS). ADCC activity was significantly down regulated in metastatic, adjuvant and t-naive patient cohorts as compared to healthy controls. Reduced ADCC activity was inversely correlated with the expression of CD107a on CD56+ cells in adjuvant patients. ADCC and ADCP activity of the patient cohorts were similar, regardless of treatment duration or additional chemotherapy. PFS in metastatic patients inversely correlated with the number of peripheral Treg cells. The reduction of ADCC in patients as compared to healthy controls calls for adjuvant strategies, such as immune-enhancing agents, to improve the activity of trastuzumab. However, efficacy of trastuzumab-specific ADCC and ADCP appears not to

  13. Dashboard systems: Pharmacokinetic/pharmacodynamic mediated dose optimization for monoclonal antibodies.

    Science.gov (United States)

    Mould, Diane R; Dubinsky, Marla C

    2015-03-01

    Many marketed drugs exhibit high variability in exposure and response. While these drugs are efficacious in their approved indications, finding appropriate dose regimens for individual patients is not straightforward. Similar dose adjustment problems are also seen with drugs that have a complex relationship between exposure and response and/or a narrow therapeutic window. This is particularly true for monoclonal antibodies, where prolonged dosing at a sub-therapeutic dose can also elicit anti-drug antibodies which will further compromise safety and efficacy. Thus, finding appropriate doses quickly would represent a substantial improvement in healthcare. Dashboard systems, which are decision-support tools, offer an improved, convenient means of tailoring treatment for individual patients. This article reviews the clinical need for this approach, particularly with monoclonal antibodies, the design, development, and testing of such systems, and the likely benefits of dashboard systems in clinical practice. We focus on infliximab for reference. © 2015, The American College of Clinical Pharmacology.

  14. Bortezomib-based treatment of acute antibody-mediated rejection: a case report.

    Science.gov (United States)

    Wang, Q; Li, X L; Xu, X G; Shi, B Y; Zhang, Z M; Li, Z L; Han, Y; Zhou, W Q; Chen, C Q; Cai, M; Zhang, X

    2015-12-22

    Antibody-mediated rejection (AMR) is an important factor affecting survival after renal transplantation. A highly selective proteasome inhibitor, bortezomib, clears activated plasma cells from the body and has important therapeutic effect on AMR. We investigated the effects of bortezomib on AMR in a patient after a second renal transplant. Biopsy confirmed the diagnosis of mixed cellular rejection and AMR. Bortezomib was administered on day 1 (1.3 mg/m(2)), day 4 (1.0 mg/m(2)), and day 8 (1.0 mg/m(2)). On the same days, 250 mg methylprednisolone was administered once, and cyclosporine dose (5 mg·kg(-1)·day(-1)) was reduced by 50%. Oral mycophenolate mofetil and steroid were withdrawn on day 1 of bortezomib treatment. Intermittent double-filtration plasmapheresis was also performed. We monitored parameters, including T lymphocyte subsets, CD139 and CD19 expression, panel reactive antibody (PRA), and serum creatinine concentration. At follow-up 6 months after bortezomib treatment, we observed: 1) serum creatinine stabilized at 130 μM from a peak level of 337 μM; 2) PRA decreased from a maximum of 66.7 to 0%; 3) blood plasma cell percentage rebounded after significantly decreasing following the first dose of bortezomib; 4) in renal allograft biopsy, immunohistochemical staining for C4d shifted from strongly positive to negative, and cellular rejection shifted from type IIA to borderline; and 5) adverse effects such as platelet suppression, hypotension, and grade 3 peripheral neuropathy emerged. Bortezomib effectively treated antibody-mediated renal transplantation rejection in this case study, but clinical trials with large sample sizes are still needed to explore clinical safety and tolerability.

  15. Antibody-mediated platelet phagocytosis by human macrophages is inhibited by siRNA specific for sequences in the SH2 tyrosine kinase, Syk.

    Science.gov (United States)

    Lu, Ying; Wang, Weiming; Mao, Huiming; Hu, Hai; Wu, Yanling; Chen, Bing-Guan; Liu, Zhongmin

    2011-01-01

    Immune thrombocytopenia depends upon Fc receptor-mediated phagocytosis that involves signaling through the SH2 tyrosine kinase, Syk. We designed small interfering (siRNA) sequences complementary to Syk coding regions to decrease the expression of Syk in the human macrophage cell line, THP-1. To evaluate the functional effect of siRNA on phagocytosis, we developed a new in vitro assay for antibody-mediated platelet ingestion by THP-1 cells. Incubation of THP-1 cells at 37°C with fluorescence-labeled platelets and anti-platelet antibody promoted ingestion of platelets that could be quantitated by flow cytometry. Transfection of THP-1 cells with Syk-specific siRNA resulted in a reduction in the amount of FcγRII-associated Syk protein. Coincident with decreased Syk expression, we observed inhibition of antibody-mediated platelet ingestion. These results confirm a key role for Syk in antibody-mediated phagocytosis and suggest Syk-specific siRNA as a possible therapeutic candidate for immune thrombocytopenia. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. INTRAVENOUS IMMUNOGLOBULIN ADMINISTRATION FOR DESENSITIZATION BEFORE RENAL TRANSPLANTATION AND MANAGING ANTIBODY-MEDIATED REJECTION

    Directory of Open Access Journals (Sweden)

    A. I. Sushkov

    2011-01-01

    Full Text Available Much attention has been placed recently in transplantation in highly HLA-sensitized patients. In attempts to remove these antibodies and enable successful renal transplantation, several approaches have been developed. Intravenous immunoglobulin (IVIG was found to be effective in the treatment of autoimmune and inflammatory disorders (e. g. Kawasaki disease, Guillain-Barre syndrome. Recently, a beneficial effect of IVIG on the reduc- tion of anti-HLA antibodies was described. The anti-inflammatory effect of IVIG provides hopeful opportunities in antibody-mediated rejection (AMR management. There are several protocols of IVIG administration for pre-transplant desensitization and AMR treatment: high-dose IVIG, low-dose IVIG + plasmapheresis, IVIG + plasmapheresis + rituximab. These advancements have enabled transplantation in patients previously considered untransplantable and in concert with new diagnostic techniques has resulted in new approaches to management of AMR. 

  17. Immunization with Clinical HIV-1 Env Proteins Induces Broad Antibody Dependent Cellular Cytotoxicity-Mediating Antibodies in a Rabbit Vaccination Model.

    Science.gov (United States)

    Karlsson, Ingrid; Borggren, Marie; Jensen, Sanne Skov; Heyndrickx, Leo; Stewart-Jones, Guillaume; Scarlatti, Gabriella; Fomsgaard, Anders

    2017-11-17

    The induction of both neutralizing antibodies and non-neutralizing antibodies with effector functions, for example, antibody-dependent cellular cytotoxicity (ADCC), is desired in the search for effective vaccines against HIV-1. In the pursuit of novel immunogens capable of inducing an efficient antibody response, rabbits were immunized with selected antigens using different prime-boost strategies. We immunized 35 different groups of rabbits with Env antigens from clinical HIV-1 subtypes A and B, including immunization with DNA alone, protein alone, and DNA prime with protein boost. The rabbit sera were screened for ADCC activity using a GranToxiLux-based assay with human peripheral blood mononuclear cells as effector cells and CEM.NKR CCR5 cells coated with HIV-1 envelope as target cells. The groups with the highest ADCC activity were further characterized for cross-reactivity between HIV-1 subtypes. The immunogen inducing the most potent and broadest ADCC response was a trimeric gp140. The ADCC activity was highest against the HIV-1 subtype corresponding to the immunogen. The ADCC activity did not necessarily reflect neutralizing activity in the pseudovirus-TZMbl assay, but there was an overall correlation between the two antiviral activities. We present a rabbit vaccination model and an assay suitable for screening HIV-1 vaccine candidates for the induction of ADCC-mediating antibodies in addition to neutralizing antibodies. The antigens and/or immunization strategies capable of inducing antibodies with ADCC activity did not necessarily induce neutralizing activity and vice versa. Nevertheless, we identified vaccine candidates that were able to concurrently induce both types of responses and that had ADCC activity that was cross-reactive between different subtypes. When searching for an effective vaccine candidate, it is important to evaluate the antibody response using a model and an assay measuring the desired function.

  18. CHALLENGES IN TREATMENT OF RENAL GRAFT ACUTE ANTIBODY-MEDIATED REJECTION

    Directory of Open Access Journals (Sweden)

    A. I. Sushkov

    2016-01-01

    Full Text Available Diagnostic criteria and treatment protocols for acute antibody-mediated rejection (AMR of kidney allograft remain controversial. We report the case of early severe AMR after primary kidney transplantation. The graft removal was considered in the absence of treatment efficacy and in the presence of systemic infl ammatory response syndrome. However, at surgery the graft looked normal and it was not removed. The repeated treatment course (plasmapheresis, antithymocyte globulin, intravenous immunoglobulin and rituximab was effective. The patient has good and stable graft function in 1 year after transplantation. 

  19. Intravenous immunoglobulins and rituximab therapy for severe transplant glomerulopathy in chronic antibody-mediated rejection: a pilot study.

    Science.gov (United States)

    Bachelet, Thomas; Nodimar, Celine; Taupin, Jean-Luc; Lepreux, Sebastien; Moreau, Karine; Morel, Delphine; Guidicelli, Gwendaline; Couzi, Lionel; Merville, Pierre

    2015-05-01

    Outcome of patients with transplant glomerulopathy (TG) is poor. Using B-cell targeting molecules represent a rational strategy to treat TG during chronic antibody-mediated rejection. In this pilot study, 21 patients with this diagnosis received four doses of intravenous immunoglobulins and two doses of rituximab (IVIG/RTX group). They were retrospectively compared with a untreated control group of 10 patients. At 24 months post-biopsy, graft survival was similar and poor between the treated and the untreated group, 47% vs. 40%, respectively, p = 0.69. This absence of response of IVIG/RTX treatment was observed, regardless the phenotype of TG. Baseline estimated glomerular filtration rate (eGFR) and decline in eGFR during the first six months after the treatment were risk factors associated with 24-month graft survival. The IVIG/RTX therapy had a modest effect on the kinetics of donor-specific alloantibodies at M24, compared to the untreated group, not associated with an improvement in graft survival. The mean number of adverse events per patient was higher in the IVIG/RTX group than in the control group (p = 0.03). Taken together, IVIG/RTX treatment for severe TG during chronic antibody-mediated rejection does not seem to change the natural history of TG and is associated with a high incidence of adverse events. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Clinical Cancer Therapy by NK Cells via Antibody-Dependent Cell-Mediated Cytotoxicity

    Directory of Open Access Journals (Sweden)

    Kory L. Alderson

    2011-01-01

    Full Text Available Natural killer (NK cells are powerful effector cells that can be directed to eliminate tumor cells through tumor-targeted monoclonal antibodies (mAbs. Some tumor-targeted mAbs have been successfully applied in the clinic and are included in the standard of care for certain malignancies. Strategies to augment the antitumor response by NK cells have led to an increased understanding of how to improve their effector responses. Next-generation reagents, such as molecularly modified mAbs and mAb-cytokine fusion proteins (immunocytokines, ICs designed to augment NK-mediated killing, are showing promise in preclinical and some clinical settings. Continued research into the antitumor effects induced by NK cells and tumor-targeted mAbs suggests that additional intrinsic and extrinsic factors may influence the antitumor response. Therefore more research is needed that focuses on evaluating which NK cell and tumor criteria are best predictive of a clinical response and which combination immunotherapy regimens to pursue for distinct clinical settings.

  1. Antibody-Mediated Targeting of Tau In Vivo Does Not Require Effector Function and Microglial Engagement

    Directory of Open Access Journals (Sweden)

    Seung-Hye Lee

    2016-08-01

    Full Text Available The spread of tau pathology correlates with cognitive decline in Alzheimer’s disease. In vitro, tau antibodies can block cell-to-cell tau spreading. Although mechanisms of anti-tau function in vivo are unknown, effector function might promote microglia-mediated clearance. In this study, we investigated whether antibody effector function is required for targeting tau. We compared efficacy in vivo and in vitro of two versions of the same tau antibody, with and without effector function, measuring tau pathology, neuron health, and microglial function. Both antibodies reduced accumulation of tau pathology in Tau-P301L transgenic mice and protected cultured neurons against extracellular tau-induced toxicity. Only the full-effector antibody enhanced tau uptake in cultured microglia, which promoted release of proinflammatory cytokines. In neuron-microglia co-cultures, only effectorless anti-tau protected neurons, suggesting full-effector tau antibodies can induce indirect toxicity via microglia. We conclude that effector function is not required for efficacy, and effectorless tau antibodies may represent a safer approach to targeting tau.

  2. Cefditoren and ceftriaxone enhance complement-mediated immunity in the presence of specific antibodies against antibiotic-resistant pneumococcal strains.

    Directory of Open Access Journals (Sweden)

    Elisa Ramos-Sevillano

    Full Text Available BACKGROUND: Specific antibodies mediate humoral and cellular protection against invading pathogens such as Streptococcus pneumoniae by activating complement mediated immunity, promoting phagocytosis and stimulating bacterial clearance. The emergence of pneumococcal strains with high levels of antibiotic resistance is of great concern worldwide and a serious threat for public health. METHODOLOGY/PRINCIPAL FINDINGS: Flow cytometry was used to determine whether complement-mediated immunity against three antibiotic-resistant S. pneumoniae clinical isolates is enhanced in the presence of sub-inhibitory concentrations of cefditoren and ceftriaxone. The binding of acute phase proteins such as C-reactive protein and serum amyloid P component, and of complement component C1q, to pneumococci was enhanced in the presence of serum plus either of these antibiotics. Both antibiotics therefore trigger the activation of the classical complement pathway against S. pneumoniae. C3b deposition was also increased in the presence of specific anti-pneumococcal antibodies and sub-inhibitory concentrations of cefditoren and ceftriaxone confirming that the presence of these antibiotics enhances complement-mediated immunity to S. pneumoniae. CONCLUSIONS/SIGNIFICANCE: Using cefditoren and ceftriaxone to promote the binding of acute phase proteins and C1q to pneumococci, and to increase C3b deposition, when anti-pneumococcal antibodies are present, might help reduce the impact of antibiotic resistance in S. pneumoniae infections.

  3. A rapid and quantitative assay for measuring antibody-mediated neutralization of West Nile virus infection

    International Nuclear Information System (INIS)

    Pierson, Theodore C.; Sanchez, Melissa D.; Puffer, Bridget A.; Ahmed, Asim A.; Geiss, Brian J.; Valentine, Laura E.; Altamura, Louis A.; Diamond, Michael S.; Doms, Robert W.

    2006-01-01

    West Nile virus (WNV) is a neurotropic flavivirus within the Japanese encephalitis antigenic complex that is responsible for causing West Nile encephalitis in humans. The surface of WNV virions is covered by a highly ordered icosahedral array of envelope proteins that is responsible for mediating attachment and fusion with target cells. These envelope proteins are also primary targets for the generation of neutralizing antibodies in vivo. In this study, we describe a novel approach for measuring antibody-mediated neutralization of WNV infection using virus-like particles that measure infection as a function of reporter gene expression. These reporter virus particles (RVPs) are produced by complementation of a sub-genomic replicon with WNV structural proteins provided in trans using conventional DNA expression vectors. The precision and accuracy of this approach stem from an ability to measure the outcome of the interaction between antibody and viral antigens under conditions that satisfy the assumptions of the law of mass action as applied to virus neutralization. In addition to its quantitative strengths, this approach allows the production of WNV RVPs bearing the prM-E proteins of different WNV strains and mutants, offering considerable flexibility for the study of the humoral immune response to WNV in vitro. WNV RVPs are capable of only a single round of infection, can be used under BSL-2 conditions, and offer a rapid and quantitative approach for detecting virus entry and its inhibition by neutralizing antibody

  4. Inhibition of EBV-mediated membrane fusion by anti-gHgL antibodies

    Energy Technology Data Exchange (ETDEWEB)

    Sathiyamoorthy, Karthik; Jiang, Jiansen; Möhl, Britta S.; Chen, Jia; Zhou, Z. Hong; Longnecker, Richard; Jardetzky, Theodore S. (UCLA); (Stanford-MED); (NWU)

    2017-09-22

    Herpesvirus entry into cells requires the coordinated action of multiple virus envelope glycoproteins, including gH, gL, and gB. For EBV, the gp42 protein assembles into complexes with gHgL heterodimers and binds HLA class II to activate gB-mediated membrane fusion with B cells. EBV tropism is dictated by gp42 levels in the virion, as it inhibits entry into epithelial cells while promoting entry into B cells. The gHgL and gB proteins are targets of neutralizing antibodies and potential candidates for subunit vaccine development, but our understanding of their neutralizing epitopes and the mechanisms of inhibition remain relatively unexplored. Here we studied the structures and mechanisms of two anti-gHgL antibodies, CL40 and CL59, that block membrane fusion with both B cells and epithelial cells. We determined the structures of the CL40 and CL59 complexes with gHgL using X-ray crystallography and EM to identify their epitope locations. CL59 binds to the C-terminal domain IV of gH, while CL40 binds to a site occupied by the gp42 receptor binding domain. CL40 binding to gHgL/gp42 complexes is not blocked by gp42 and does not interfere with gp42 binding to HLA class II, indicating that its ability to block membrane fusion with B cells represents a defect in gB activation. These data indicate that anti-gHgL neutralizing antibodies can block gHgL-mediated activation of gB through different surface epitopes and mechanisms.

  5. Antibody tumor penetration: transport opposed by systemic and antigen-mediated clearance.

    Science.gov (United States)

    Thurber, Greg M; Schmidt, Michael M; Wittrup, K Dane

    2008-09-01

    Antibodies have proven to be effective agents in cancer imaging and therapy. One of the major challenges still facing the field is the heterogeneous distribution of these agents in tumors when administered systemically. Large regions of untargeted cells can therefore escape therapy and potentially select for more resistant cells. We present here a summary of theoretical and experimental approaches to analyze and improve antibody penetration in tumor tissue.

  6. Maternal Antibody-Mediated Disease Enhancement in Type I Interferon-Deficient Mice Leads to Lethal Disease Associated with Liver Damage.

    Directory of Open Access Journals (Sweden)

    Julia María Martínez Gómez

    2016-03-01

    Full Text Available Epidemiological studies have reported that most of the severe dengue cases occur upon a secondary heterologous infection. Furthermore, babies born to dengue immune mothers are at greater risk of developing severe disease upon primary infection with a heterologous or homologous dengue virus (DENV serotype when maternal antibodies reach sub-neutralizing concentrations. These observations have been explained by the antibody mediated disease enhancement (ADE phenomenon whereby heterologous antibodies or sub-neutralizing homologous antibodies bind to but fail to neutralize DENV particles, allowing Fc-receptor mediated entry of the virus-antibody complexes into host cells. This eventually results in enhanced viral replication and heightened inflammatory responses. In an attempt to replicate this ADE phenomenon in a mouse model, we previously reported that upon DENV2 infection 5-week old type I and II interferon (IFN receptors-deficient mice (AG129 born to DENV1-immune mothers displayed enhancement of disease severity characterized by increased virus titers and extensive vascular leakage which eventually led to the animals' death. However, as dengue occurs in immune competent individuals, we sought to reproduce this mouse model in a less immunocompromised background. Here, we report an ADE model that is mediated by maternal antibodies in type I IFN receptor-deficient A129 mice. We show that 5-week old A129 mice born to DENV1-immune mothers succumbed to a DENV2 infection within 4 days that was sub-lethal in mice born to naïve mothers. Clinical manifestations included extensive hepatocyte vacuolation, moderate vascular leakage, lymphopenia, and thrombocytopenia. Anti-TNFα therapy totally protected the mice and correlated with healthy hepatocytes. In contrast, blocking IL-6 did not impact the virus titers or disease outcome. This A129 mouse model of ADE may help dissecting the mechanisms involved in dengue pathogenesis and evaluate the efficacy of

  7. Human anti-CAIX antibodies mediate immune cell inhibition of renal cell carcinoma in vitro and in a humanized mouse model in vivo.

    Science.gov (United States)

    Chang, De-Kuan; Moniz, Raymond J; Xu, Zhongyao; Sun, Jiusong; Signoretti, Sabina; Zhu, Quan; Marasco, Wayne A

    2015-06-11

    Carbonic anhydrase (CA) IX is a surface-expressed protein that is upregulated by the hypoxia inducible factor (HIF) and represents a prototypic tumor-associated antigen that is overexpressed on renal cell carcinoma (RCC). Therapeutic approaches targeting CAIX have focused on the development of CAIX inhibitors and specific immunotherapies including monoclonal antibodies (mAbs). However, current in vivo mouse models used to characterize the anti-tumor properties of fully human anti-CAIX mAbs have significant limitations since the role of human effector cells in tumor cell killing in vivo is not directly evaluated. The role of human anti-CAIX mAbs on CAIX(+) RCC tumor cell killing by immunocytes or complement was tested in vitro by antibody-dependent cell-mediated cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC) and antibody-dependent cellular phagocytosis (ADCP) as well as on CAIX(+) RCC cellular motility, wound healing, migration and proliferation. The in vivo therapeutic activity mediated by anti-CAIX mAbs was determined by using a novel orthotopic RCC xenograft humanized animal model and analyzed by histology and FACS staining. Our studies demonstrate the capacity of human anti-CAIX mAbs that inhibit CA enzymatic activity to result in immune-mediated killing of RCC, including nature killer (NK) cell-mediated ADCC, CDC, and macrophage-mediated ADCP. The killing activity correlated positively with the level of CAIX expression on RCC tumor cell lines. In addition, Fc engineering of anti-CAIX mAbs was shown to enhance the ADCC activity against RCC. We also demonstrate that these anti-CAIX mAbs inhibit migration of RCC cells in vitro. Finally, through the implementation of a novel orthotopic RCC model utilizing allogeneic human peripheral blood mononuclear cells in NOD/SCID/IL2Rγ(-/-) mice, we show that anti-CAIX mAbs are capable of mediating human immune response in vivo including tumor infiltration of NK cells and activation of T cells, resulting in

  8. Target-mediated drug disposition model and its approximations for antibody-drug conjugates.

    Science.gov (United States)

    Gibiansky, Leonid; Gibiansky, Ekaterina

    2014-02-01

    Antibody-drug conjugate (ADC) is a complex structure composed of an antibody linked to several molecules of a biologically active cytotoxic drug. The number of ADC compounds in clinical development now exceeds 30, with two of them already on the market. However, there is no rigorous mechanistic model that describes pharmacokinetic (PK) properties of these compounds. PK modeling of ADCs is even more complicated than that of other biologics as the model should describe distribution, binding, and elimination of antibodies with different toxin load, and also the deconjugation process and PK of the released toxin. This work extends the target-mediated drug disposition (TMDD) model to describe ADCs, derives the rapid binding (quasi-equilibrium), quasi-steady-state, and Michaelis-Menten approximations of the TMDD model as applied to ADCs, derives the TMDD model and its approximations for ADCs with load-independent properties, and discusses further simplifications of the system under various assumptions. The developed models are shown to describe data simulated from the available clinical population PK models of trastuzumab emtansine (T-DM1), one of the two currently approved ADCs. Identifiability of model parameters is also discussed and illustrated on the simulated T-DM1 examples.

  9. Modulating Cytotoxic Effector Functions by Fc Engineering to Improve Cancer Therapy.

    Science.gov (United States)

    Kellner, Christian; Otte, Anna; Cappuzzello, Elisa; Klausz, Katja; Peipp, Matthias

    2017-09-01

    In the last two decades, monoclonal antibodies have revolutionized the therapy of cancer patients. Although antibody therapy has continuously been improved, still a significant number of patients do not benefit from antibody therapy. Therefore, rational optimization of the antibody molecule by Fc engineering represents a major area of translational research to further improve this potent therapeutic option. Monoclonal antibodies are able to trigger a variety of effector mechanisms. Especially Fc-mediated effector functions such as antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and complement- dependent cytotoxicity (CDC) are considered important in antibody therapy of cancer. Novel mechanistic insights into the action of monoclonal antibodies allowed the development of various Fc engineering approaches to modulate antibodies' effector functions. Strategies in modifying the Fc glycosylation profile (Fc glyco-engineering) or approaches in engineering the protein backbone (Fc protein engineering) have been intensively evaluated. In the current review, Fc engineering strategies resulting in improved ADCC, ADCP and CDC activity are summarized and discussed.

  10. Antibody-mediated modulation of cytokinins in tobacco: Organ-specific changes in cytokinin homeostasis

    Czech Academy of Sciences Publication Activity Database

    Gelová, Z.; Hoopen, P.; Novák, Ondřej; Motyka, Václav; Pernisová, M.; Dabravolski, S.; Didi, V.; Tillack, F.; Oklešťková, Jana; Strnad, Miroslav; Hause, B.; Haruštiaková, D.; Conrad, U.; Janda, L.; Hejátko, J.

    2018-01-01

    Roč. 69, č. 3 (2018), s. 441-454 ISSN 0022-0957 R&D Projects: GA MŠk(CZ) LQ1601; GA MŠk(CZ) LO1204; GA MŠk(CZ) LM2015062; GA ČR(CZ) GA16-14649S Institutional support: RVO:61389030 Keywords : Antibody-mediated modulation * biosynthesis * ckx * cytokinin * homeostasis * organ specificity * tobacco Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 5.830, year: 2016

  11. Relationship between natural and heme-mediated antibody polyreactivity

    Energy Technology Data Exchange (ETDEWEB)

    Hadzhieva, Maya; Vassilev, Tchavdar [Stephan Angelov Institute of Microbiology, Bulgarian Academy of Sciences, Sofia 1113 (Bulgaria); Bayry, Jagadeesh; Kaveri, Srinivas; Lacroix-Desmazes, Sébastien [Sorbonne Universités, UPMC Univ Paris 06, UMR-S 1138, Centre de Recherche des Cordeliers, F-75006 Paris (France); INSERM, UMR-S 1138, F-75006 Paris (France); Université Paris Descartes, Sorbonne Paris Cité, UMR-S 1138, F-75006 Paris (France); Dimitrov, Jordan D., E-mail: jordan.dimitrov@crc.jussieu.fr [Sorbonne Universités, UPMC Univ Paris 06, UMR-S 1138, Centre de Recherche des Cordeliers, F-75006 Paris (France); INSERM, UMR-S 1138, F-75006 Paris (France); Université Paris Descartes, Sorbonne Paris Cité, UMR-S 1138, F-75006 Paris (France)

    2016-03-25

    Polyreactive antibodies represent a considerable fraction of the immune repertoires. Some antibodies acquire polyreactivity post-translationally after interaction with various redox-active substances, including heme. Recently we have demonstrated that heme binding to a naturally polyreactive antibody (SPE7) results in a considerable broadening of the repertoire of recognized antigens. A question remains whether the presence of certain level of natural polyreactivity of antibodies is a prerequisite for heme-induced further extension of antigen binding potential. Here we used a second monoclonal antibody (Hg32) with unknown specificity and absence of intrinsic polyreactivity as a model to study the potential of heme to induce polyreactivity of antibodies. We demonstrated that exposure to heme greatly extends the antigen binding potential of Hg32, suggesting that the intrinsic binding promiscuity is not a prerequisite for the induction of polyreactivity by heme. In addition we compared the kinetics and thermodynamics of the interaction of heme-exposed antibodies with a panel of unrelated antigens. These analyses revealed that the two heme-sensitive antibodies adopt different mechanisms of binding to the same set of antigens. This study contributes to understanding the phenomenon of induced antibody polyreactivity. The data may also be of importance for understanding of physiological and pathological roles of polyreactive antibodies. - Highlights: • Exposure of certain monoclonal IgE antibodies to heme results in gain of antigen binding polyreactivity. • Natural polyreactivity of antibodies is dispensable for acquisition of polyreactivity through interaction with heme. • Heme-induced monoclonal IgE antibodies differ in their thermodynamic mechanisms of antigen recognition.

  12. FcγRII-binding Centyrins mediate agonism and antibody-dependent cellular phagocytosis when fused to an anti-OX40 antibody.

    Science.gov (United States)

    Zhang, Di; Whitaker, Brian; Derebe, Mehabaw G; Chiu, Mark L

    2018-04-01

    Immunostimulatory antibodies against the tumor necrosis factor receptors (TNFR) are emerging as promising cancer immunotherapies. The agonism activity of such antibodies depends on crosslinking to Fc gamma RIIB receptor (FcγRIIB) to enable the antibody multimerization that drives TNFR activation. Previously, Fc engineering was used to enhance the binding of such antibodies to Fcγ receptors. Here, we report the identification of Centyrins as alternative scaffold proteins with binding affinities to homologous FcγRIIB and FcγRIIA, but not to other types of Fcγ receptors. One Centyrin, S29, was engineered at distinct positions of an anti-OX40 SF2 antibody to generate bispecific and tetravalent molecules named as mAbtyrins. Regardless of the position of S29 on the SF2 antibody, SF2-S29 mAbtyrins could bind FcγRIIB and FcγRIIA specifically while maintaining binding to OX40 receptors. In a NFκB reporter assay, attachment of S29 Centyrin molecules at the C-termini, but not the N-termini, resulted in SF2 antibodies with increased agonism owing to FcγRIIB crosslinking. The mAbtyrins also showed agonism in T-cell activation assays with immobilized FcγRIIB and FcγRIIA, but this activity was confined to mAbtyrins with S29 specifically at the C-termini of antibody heavy chains. Furthermore, regardless of the position of the molecule, S29 Centyrin could equip an otherwise Fc-silent antibody with antibody-dependent cellular phagocytosis activity without affecting the antibody's intrinsic antibody-dependent cell-meditated cytotoxicity and complement-dependent cytotoxicity. In summary, the appropriate adoption FcγRII-binding Centyrins as functional modules represents a novel strategy to engineer therapeutic antibodies with improved functionalities.

  13. Antibody-Mediated Extreme Insulin Resistance: A Report of Three Cases.

    Science.gov (United States)

    Kim, Han Na; Fesseha, Betiel; Anzaldi, Laura; Tsao, Allison; Galiatsatos, Panagis; Sidhaye, Aniket

    2018-01-01

    Type 2 diabetes mellitus is characterized by relative insulin deficiency and insulin resistance. Features suggesting severe insulin resistance include acanthosis nigricans, hyperandrogenism, weight loss, and recurrent hospital admissions for diabetic ketoacidosis. In rare circumstances, hyperglycemia persists despite administration of massive doses of insulin. In these cases, it is important to consider autoimmune etiologies for insulin resistance, such as type B insulin resistance and insulin antibody-mediated extreme insulin resistance, which carry high morbidity and mortality if untreated. Encouragingly, immunomodulatory regimens have recently been published that induce remission at high rates. We describe 3 cases of extreme insulin resistance mediated by anti-insulin receptor autoantibodies or insulin autoantibodies. All cases were effectively treated with an immunomodulatory regimen. Although cases of extreme insulin resistance are rare, it is important to be aware of autoimmune causes, recognize suggestive signs and symptoms, and pursue appropriate diagnostic evaluation. Prompt treatment with immunomodulators is key to restoring euglycemia in patients with autoimmune etiologies of insulin resistance. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. Adjuvant-Mediated Epitope Specificity and Enhanced Neutralizing Activity of Antibodies Targeting Dengue Virus Envelope Protein

    Directory of Open Access Journals (Sweden)

    Denicar Lina Nascimento Fabris Maeda

    2017-09-01

    Full Text Available The heat-labile toxins (LT produced by enterotoxigenic Escherichia coli display adjuvant effects to coadministered antigens, leading to enhanced production of serum antibodies. Despite extensive knowledge of the adjuvant properties of LT derivatives, including in vitro-generated non-toxic mutant forms, little is known about the capacity of these adjuvants to modulate the epitope specificity of antibodies directed against antigens. This study characterizes the role of LT and its non-toxic B subunit (LTB in the modulation of antibody responses to a coadministered antigen, the dengue virus (DENV envelope glycoprotein domain III (EDIII, which binds to surface receptors and mediates virus entry into host cells. In contrast to non-adjuvanted or alum-adjuvanted formulations, antibodies induced in mice immunized with LT or LTB showed enhanced virus-neutralization effects that were not ascribed to a subclass shift or antigen affinity. Nonetheless, immunosignature analyses revealed that purified LT-adjuvanted EDIII-specific antibodies display distinct epitope-binding patterns with regard to antibodies raised in mice immunized with EDIII or the alum-adjuvanted vaccine. Notably, the analyses led to the identification of a specific EDIII epitope located in the EF to FG loop, which is involved in the entry of DENV into eukaryotic cells. The present results demonstrate that LT and LTB modulate the epitope specificity of antibodies generated after immunization with coadministered antigens that, in the case of EDIII, was associated with the induction of neutralizing antibody responses. These results open perspectives for the more rational development of vaccines with enhanced protective effects against DENV infections.

  15. Soluble CD30 and Hepatocyte growth factor as predictive markers of antibody-mediated rejection of the kidney allograft.

    Science.gov (United States)

    Pavlova, Yelena; Viklicky, Ondrej; Slatinska, Janka; Bürgelova, Marcela; Süsal, Caner; Skibova, Jelena; Honsová, Eva; Striz, Ilja; Kolesar, Libor; Slavcev, Antonij

    2011-07-01

    Our retrospective study was aimed to assess the relevance of pre- and post-transplant measurements of serum concentrations of the soluble CD30 molecule (soluble CD30, sCD30) and the cytokine Hepatocyte growth factor (HGF) for prediction of the risk for development of antibody-mediated rejection (AMR) in kidney transplant patients. Evaluation of sCD30, HGF levels and the presence of HLA-specific antibodies in a cohort of 205 patients was performed before, 2weeks and 6months after transplantation. Patients were followed up for kidney graft function and survival for two years. We found a tendency of higher incidence of AMR in retransplanted patients with elevated pre-transplant sCD30 (≥100U/ml) (p=0.051), however no such correlation was observed in first-transplant patients. Kidney recipients with simultaneously high sCD30 and HLA-specific antibodies (sCD30+/Ab+) before transplantation had significantly lower AMR-free survival compared to the other patient groups (psCD30 showed increased incidence of AMR in recipients with elevated pretransplant sCD30 and low HGF levels. the predictive value of pretransplant sCD30 for the development of antibody-mediated rejection after transplantation is significantly potentiated by the co-presence of HLA specific antibodies. The role of HGF as a rejection-protective factor in patients with high pretransplant HGF levels would need further investigation. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Developing models of how cognitive improvements change functioning: Mediation, moderation and moderated mediation

    Science.gov (United States)

    Wykes, Til; Reeder, Clare; Huddy, Vyv; Taylor, Rumina; Wood, Helen; Ghirasim, Natalia; Kontis, Dimitrios; Landau, Sabine

    2012-01-01

    Background Cognitive remediation (CRT) affects functioning but the extent and type of cognitive improvements necessary are unknown. Aim To develop and test models of how cognitive improvement transfers to work behaviour using the data from a current service. Method Participants (N49) with a support worker and a paid or voluntary job were offered CRT in a Phase 2 single group design with three assessments: baseline, post therapy and follow-up. Working memory, cognitive flexibility, planning and work outcomes were assessed. Results Three models were tested (mediation — cognitive improvements drive functioning improvement; moderation — post treatment cognitive level affects the impact of CRT on functioning; moderated mediation — cognition drives functioning improvements only after a certain level is achieved). There was evidence of mediation (planning improvement associated with improved work quality). There was no evidence that cognitive flexibility (total Wisconsin Card Sorting Test errors) and working memory (Wechsler Adult Intelligence Scale III digit span) mediated work functioning despite significant effects. There was some evidence of moderated mediation for planning improvement if participants had poorer memory and/or made fewer WCST errors. The total CRT effect on work quality was d = 0.55, but the indirect (planning-mediated CRT effect) was d = 0.082 Conclusion Planning improvements led to better work quality but only accounted for a small proportion of the total effect on work outcome. Other specific and non-specific effects of CRT and the work programme are likely to account for some of the remaining effect. This is the first time complex models have been tested and future Phase 3 studies need to further test mediation and moderated mediation models. PMID:22503640

  17. Tyrosine kinase inhibitors as modulators of trastuzumab-mediated antibody-dependent cell-mediated cytotoxicity in breast cancer cell lines.

    Science.gov (United States)

    Collins, Denis M; Gately, Kathy; Hughes, Clare; Edwards, Connla; Davies, Anthony; Madden, Stephen F; O'Byrne, Kenneth J; O'Donovan, Norma; Crown, John

    2017-09-01

    Trastuzumab is an anti-HER2 monoclonal antibody (mAb) therapy capable of antibody-dependent cell-mediated cytotoxicity (ADCC) and used in the treatment of HER2+ breast cancer. Through interactions with FcƴR+ immune cell subsets, trastuzumab functions as a passive immunotherapy. The EGFR/HER2-targeting tyrosine kinase inhibitor (TKI) lapatinib and the next generation TKIs afatinib and neratinib, can alter HER2 levels, potentially modulating the ADCC response to trastuzumab. Using LDH-release assays, we investigated the impact of antigen modulation, assay duration and peripheral blood mononuclear cell (PBMC) activity on trastuzumab-mediated ADCC in breast cancer models of maximal (SKBR3) and minimal (MCF-7) target antigen expression to determine if modulating the ADCC response to trastuzumab using TKIs may be a viable approach for enhancing tumor immune reactivity. HER2 levels were determined in lapatinib, afatinib and neratinib-treated SKBR3 and MCF-7 using high content analysis (HCA). Trastuzumab-mediated ADCC was assessed following treatment with TKIs utilising a colorimetric LDH release-based protocol at 4 and 12h timepoints. PBMC activity was assessed against non-MHC-restricted K562 cells. A flow cytometry-based method (CFSE/7-AAD) was also used to measure trastuzumab-mediated ADCC in medium-treated SKBR3 and MCF-7. HER2 antigen levels were significantly altered by the three TKIs in both cell line models. The TKIs significantly reduced LDH levels directly in SKBR3 cells but not MCF-7. Lapatinib and neratinib augment trastuzumab-related ADCC in SKBR3 but the effect was not consistent with antigen expression levels and was dependent on volunteer PBMC activity (vs. K562). A 12h assay timepoint produced more consistent results. Trastuzumab-mediated ADCC (PBMC:target cell ratio of 10:1) was measured at 7.6±4.7% (T12) by LDH assay and 19±3.2 % (T12) using the flow cytometry-based method in the antigen-low model MCF-7. In the presence of effector cells with high

  18. Antibody-mediated enzyme replacement therapy targeting both lysosomal and cytoplasmic glycogen in Pompe disease.

    Science.gov (United States)

    Yi, Haiqing; Sun, Tao; Armstrong, Dustin; Borneman, Scott; Yang, Chunyu; Austin, Stephanie; Kishnani, Priya S; Sun, Baodong

    2017-05-01

    Pompe disease is characterized by accumulation of both lysosomal and cytoplasmic glycogen primarily in skeletal and cardiac muscles. Mannose-6-phosphate receptor-mediated enzyme replacement therapy (ERT) with recombinant human acid α-glucosidase (rhGAA) targets the enzyme to lysosomes and thus is unable to digest cytoplasmic glycogen. Studies have shown that anti-DNA antibody 3E10 penetrates living cells and delivers "cargo" proteins to the cytosol or nucleus via equilibrative nucleoside transporter ENT2. We speculate that 3E10-mediated ERT with GAA will target both lysosomal and cytoplasmic glycogen in Pompe disease. A fusion protein (FabGAA) containing a humanized Fab fragment derived from the murine 3E10 antibody and the 110 kDa human GAA precursor was constructed and produced in CHO cells. Immunostaining with an anti-Fab antibody revealed that the Fab signals did not co-localize with the lysosomal marker LAMP2 in cultured L6 myoblasts or Pompe patient fibroblasts after incubation with FabGAA. Western blot with an anti-GAA antibody showed presence of the 150 kDa full-length FabGAA in the cell lysates, in addition to the 95- and 76 kDa processed forms of GAA that were also seen in the rhGAA-treated cells. Blocking of mannose-6-phosphate receptor with mannose-6-phosphate markedly reduced the 95- and the 76 kDa forms but not the 150 kDa form. In GAA-KO mice, FabGAA achieved similar treatment efficacy as rhGAA at an equal molar dose in reducing tissue glycogen contents. Our data suggest that FabGAA retains the ability of rhGAA to treat lysosomal glycogen accumulation and has the beneficial potential over rhGAA to reduce cytoplasmic glycogen storage in Pompe disease. FabGAA can be delivered to both the cytoplasm and lysosomes in cultured cells. FabGAA equally reduced lysosomal glycogen accumulation as rhGAA in GAA-KO mice. FabGAA has the beneficial potential over rhGAA to clear cytoplasmic glycogen. This study suggests a novel antibody-enzyme fusion protein therapy

  19. Lymphocyte antibody-dependent cytotoxicity test for evaluation of clinical role of monoclonal anti-D-antibodies for prevention of rhesus sensitization.

    Science.gov (United States)

    Olovnikova, N I; Belkina, E V; Nikolaeva, T L; Miterev, G Yu; Chertkov, I L

    2006-01-01

    Monoclonal antibodies to D antigen were studied in the reaction of antibody-dependent cytotoxicity for evaluation of the possibility of using these antibodies for preventing rhesus sensitization. High hemolytic activity of four anti-D-monoclonal antibodies in the antibody-dependent cytotoxicity test, mediated by their interaction with FcgammaRI, and the capacity to accelerate elimination of D+ erythrocytes from circulation did not provide the immunosuppressive effect. It was hypothesized that monoclonal antibodies for prevention of rhesus sensitization should interact with FcgammaRIII on lymphocytes. These monoclonal antibodies are extremely rare: only 4 of 125 studied antibodies mediated hemolysis in the antibody-dependent cytotoxicity test with lymphocytes, while all polyclonal anti-D-preparations exhibited this activity.

  20. Fcγ-receptor IIa-mediated Src Signaling Pathway Is Essential for the Antibody-Dependent Enhancement of Ebola Virus Infection.

    Directory of Open Access Journals (Sweden)

    Wakako Furuyama

    2016-12-01

    Full Text Available Antibody-dependent enhancement (ADE of Ebola virus (EBOV infection has been demonstrated in vitro, raising concerns about the detrimental potential of some anti-EBOV antibodies. ADE has been described for many viruses and mostly depends on the cross-linking of virus-antibody complexes to cell surface Fc receptors, leading to enhanced infection. However, little is known about the molecular mechanisms underlying this phenomenon. Here we show that Fcγ-receptor IIa (FcγRIIa-mediated intracellular signaling through Src family protein tyrosine kinases (PTKs is required for ADE of EBOV infection. We found that deletion of the FcγRIIa cytoplasmic tail abolished EBOV ADE due to decreased virus uptake into cellular endosomes. Furthermore, EBOV ADE, but not non-ADE infection, was significantly reduced by inhibition of the Src family protein PTK pathway, which was also found to be important to promote phagocytosis/macropinocytosis for viral uptake into endosomes. We further confirmed a significant increase of the Src phosphorylation mediated by ADE. These data suggest that antibody-EBOV complexes bound to the cell surface FcγRIIa activate the Src signaling pathway that leads to enhanced viral entry into cells, providing a novel perspective for the general understanding of ADE of virus infection.

  1. Enhanced killing of chordoma cells by antibody-dependent cell-mediated cytotoxicity employing the novel anti-PD-L1 antibody avelumab.

    Science.gov (United States)

    Fujii, Rika; Friedman, Eitan R; Richards, Jacob; Tsang, Kwong Y; Heery, Christopher R; Schlom, Jeffrey; Hodge, James W

    2016-06-07

    Chordoma, a rare bone tumor derived from the notochord, has been shown to be resistant to conventional therapies. Checkpoint inhibition has shown great promise in immune-mediated therapy of diverse cancers. The anti-PD-L1 mAb avelumab is unique among checkpoint inhibitors in that it is a fully human IgG1 capable of mediating antibody-dependent cell-mediated cytotoxicity (ADCC) of PD-L1-expressing tumor cells. Here, we investigated avelumab as a potential therapy for chordoma. We examined 4 chordoma cell lines, first for expression of PD-L1, and in vitro for ADCC killing using NK cells and avelumab. PD-L1 expression was markedly upregulated by IFN-γ in all 4 chordoma cell lines, which significantly increased sensitivity to ADCC. Brachyury is a transcription factor that is uniformly expressed in chordoma. Clinical trials are ongoing in which chordoma patients are treated with brachyury-specific vaccines. Co-incubating chordoma cells with brachyury-specific CD8+ T cells resulted in significant upregulation of PD-L1 on the tumor cells, mediated by the CD8+ T cells' IFN-γ production, and increased sensitivity of chordoma cells to avelumab-mediated ADCC. Residential cancer stem cell subpopulations of chordoma cells were also killed by avelumab-mediated ADCC to the same degree as non-cancer stem cell populations. These findings suggest that as a monotherapy for chordoma, avelumab may enable endogenous NK cells, while in combination with T-cell immunotherapy, such as a vaccine, avelumab may enhance NK-cell killing of chordoma cells via ADCC.

  2. Late acute antibody mediated rejection after nine years of renal transplantation

    Directory of Open Access Journals (Sweden)

    Halim Medhat

    2010-01-01

    Full Text Available Acute Antibody Mediated Rejection (AMR is rarely reported as a long-term com-plication of renal transplantation, and it can present on top of another chronic pathology affecting the graft. A 45-year-old gentleman with chronic kidney disease due to unknown etiology received renal transplantation from his sister with 4 HLA mismatches. He received antithymocte globulin induction therapy and was maintained on steroids, azathioprine (AZA and cyclosporine A (CsA. Up to eight years post-transplantation he was clinically and biochemically stable. He lost follow-up for about one year, and then presented with nephritic nephrotic syndrome and rise of serum creatinine (SCr. to 210 μmol/L. Graft biopsy revealed picture suggestive of acute AMR on top of de novo membranoprolipherative glomerulonephritis (MPGN with focal crescent formation, diffuse immune complex deposition and peri-tubular capillaries C4d positivity. Anti-HLA donor specific antibodies were highly positive for B and T cells class I and class II. The patient was treated with intravenous immunoglobulin, plasma exchange and anti-CD20 (rituximab. AZA was changed to mycophenolate mofetil and CsA to tacrolimus. He had partial response, but SCr. continued at 220 μmol/L.

  3. Acute Liver Allograft Antibody-Mediated Rejection: an inter-institutional study of routine histopathological features

    OpenAIRE

    O'Leary, Jacqueline G.; Shiller, S. Michelle; Bellamy, Christopher; Nalesnik, Michael A.; Kaneku, Hugo; Terasaki, Paul I.; Klintmalm, Göran B.; Demetris, Anthony J.

    2014-01-01

    Acute antibody-mediated rejection (AMR) occurs in a minority of sensitized liver transplant recipients. Although histopathologic characteristics have been described, a generalizable scoring system used to trigger a more in-depth analysis is needed to screen for this rare but important finding. Toward this goal, we created a training and validation cohort from 3 high volume liver transplant programs of putative acute AMR and control cases that were evaluated blindly by 4 independent transplant...

  4. Secondary antibodies as tools to improve tumor to non tumor ratio at radioimmunolocalisation and radioimmunotherapy

    International Nuclear Information System (INIS)

    Ullen, A.; Riklund Aalstroem, K.; Hietala, S.O.; Nilsson, B.; Aerlestig, L.; Stigbrand, T.

    1996-01-01

    One way of selectively improving the efficiency of radioimmunolocalization and radioimmunotherapy is to eliminate redundant, circulating, non-targeting radiolabeled antibodies after saturation of the target sites. Secondary antibodies of different types have been proposed as clearing agents for such purposes. The conceptually different approaches of the 'secondary antibody' strategy including its advantages and limitations are discussed. This mini-review also presents a model describing the kinetics of the components (the antigen, the primary and secondary antibodies) and approaches required to improve the efficacy of both radioimmunolocalization and radioimmunotherapy. (orig.)

  5. Acute liver allograft antibody-mediated rejection:an inter-institutional study of significant histopathological features

    OpenAIRE

    O'Leary, Jacqueline G; Shiller, S Michelle; Bellamy, Christopher; Nalesnik, Michael A; Kaneku, Hugo; Jennings, Linda W; Isse, Kumiko; Terasaki, Paul I; Klintmalm, Göran B; Demetris, Anthony J

    2014-01-01

    Acute antibody-mediated rejection (AMR) occurs in a small minority of sensitized liver transplant recipients. Although histopathologic characteristics have been described, specific features that could be used: a) for a generalizable scoring system; and b) to trigger a more in-depth analysis are needed to screen for this rare but important finding. Toward this goal, we created a training and validation cohort from 3 high volume liver transplant programs of putative acute AMR and control cases ...

  6. Macrophage and NK-mediated killing of precursor-B acute lymphoblastic leukemia cells targeted with a-fucosylated anti-CD19 humanized antibodies.

    Science.gov (United States)

    Matlawska-Wasowska, K; Ward, E; Stevens, S; Wang, Y; Herbst, R; Winter, S S; Wilson, B S

    2013-06-01

    This work reports the tumoricidal effects of a novel investigational humanized anti-CD19 monoclonal antibody (Medi-551). An a-fucosylated antibody with increased affinity for human FcγRIIIA, Medi-551 is shown to mediate both antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). Medi-551/CD19 complexes internalize slowly (>5 h) and thus remain accessible to effector cells for prolonged periods. We evaluated in vitro ADCC and ADCP activities of primary human natural killer (NK) cells and macrophages against precursor-B (pre-B) acute lymphoblastic leukemia (ALL) cell lines and pediatric patient blasts. Fluorescent imaging studies document immunological synapses formed between anti-CD19-bound target leukemia cells and effector cells and capture the kinetics of both NK-mediated killing and macrophage phagocytosis. Genetic polymorphisms in FcγRIIIA-158F/V modulate in vitro activities of effector cells, with FcγRIIIA-158V homozygotes or heterozygotes showing the strongest activity. Medi-551 treatment of severe combined immunodeficiency (SCID) mice engrafted with human pre-B cells led to prolonged animal survival and markedly reduced disease burden in blood, liver and bone marrow. These data show that anti-CD19 antibodies effectively recruit immune cells to pre-B ALL cells and support a move forward to early phase trials in this disease.

  7. Improved Lysosomal Trafficking Can Modulate the Potency of Antibody Drug Conjugates.

    Science.gov (United States)

    DeVay, Rachel M; Delaria, Kathy; Zhu, Guoyun; Holz, Charles; Foletti, Davide; Sutton, Janette; Bolton, Gary; Dushin, Russell; Bee, Christine; Pons, Jaume; Rajpal, Arvind; Liang, Hong; Shelton, David; Liu, Shu-Hui; Strop, Pavel

    2017-04-19

    Antibody drug conjugates (ADCs) provide an efficacious and relatively safe means by which chemotherapeutic agents can be specifically targeted to cancer cells. In addition to the selection of antibody targets, ADCs offer a modular design that allows selection of ADC characteristics through the choice of linker chemistries, toxins, and conjugation sites. Many studies have indicated that release of toxins bound to antibodies via noncleavable linker chemistries relies on the internalization and intracellular trafficking of the ADC. While this can make noncleavable ADCs more stable in the serum, it can also result in lower efficacy when their respective targets are not internalized efficiently or are recycled back to the cell surface following internalization. Here, we show that a lysosomally targeted ADC against the protein APLP2 mediates cell killing, both in vitro and in vivo, more effectively than an ADC against Trop2, a protein with less efficient lysosomal targeting. We also engineered a bispecific ADC with one arm targeting HER2 for the purpose of directing the ADC to tumors, and the other arm targeting APLP2, whose purpose is to direct the ADC to lysosomes for toxin release. This proof-of-concept bispecific ADC demonstrates that this technology can be used to shift the intracellular trafficking of a constitutively recycled target by directing one arm of the antibody against a lysosomally delivered protein. Our data also show limitations of this approach and potential future directions for development.

  8. B7h-expressing dendritic cells and plasma B cells mediate distinct outcomes of ICOS costimulation in T cell-dependent antibody responses

    Directory of Open Access Journals (Sweden)

    Larimore Kevin

    2012-06-01

    Full Text Available Abstract Background The ICOS-B7h costimulatory receptor-ligand pair is required for germinal center formation, the production of isotype-switched antibodies, and antibody affinity maturation in response to T cell-dependent antigens. However, the potentially distinct roles of regulated B7h expression on B cells and dendritic cells in T cell-dependent antibody responses have not been defined. Results We generated transgenic mice with lineage-restricted B7h expression to assess the cell-type specific roles of B7h expression on B cells and dendritic cells in regulating T cell-dependent antibody responses. Our results show that endogenous B7h expression is reduced on B cells after activation in vitro and is also reduced in vivo on antibody-secreting plasma B cells in comparison to both naïve and germinal center B cells from which they are derived. Increasing the level of B7h expression on activated and plasma B cells in B-B7hTg mice led to an increase in the number of antibody-secreting plasma cells generated after immunization and a corresponding increase in the concentration of antigen-specific high affinity serum IgG antibodies of all isotypes, without affecting the number of responding germinal center B cells. In contrast, ICOS costimulation mediated by dendritic cells in DC-B7hTg mice contributed to germinal center formation and selectively increased IgG2a production without affecting the overall magnitude of antibody responses. Conclusions Using transgenic mice with lineage-restricted B7h expression, we have revealed distinct roles of ICOS costimulation mediated by dendritic cells and B cells in the regulation of T cell-dependent antibody responses.

  9. Vibrio cholerae O1 secretes an extracellular matrix in response to antibody-mediated agglutination.

    Directory of Open Access Journals (Sweden)

    Danielle E Baranova

    Full Text Available Vibrio cholerae O1 is one of two serogroups responsible for epidemic cholera, a severe watery diarrhea that occurs after the bacterium colonizes the human small intestine and secretes a potent ADP-ribosylating toxin. Immunity to cholera is associated with intestinal anti-lipopolysaccharide (LPS antibodies, which are known to inhibit V. cholerae motility and promote bacterial cell-cell crosslinking and aggregation. Here we report that V. cholerae O1 classical and El Tor biotypes produce an extracellular matrix (ECM when forcibly immobilized and agglutinated by ZAC-3 IgG, an intestinally-derived monoclonal antibody (MAb against the core/lipid A region of LPS. ECM secretion, as demonstrated by crystal violet staining and scanning electron microscopy, occurred within 30 minutes of antibody exposure and peaked by 3 hours. Non-motile mutants of V. cholerae did not secrete ECM following ZAC-3 IgG exposure, even though they were susceptible to agglutination. The ECM was enriched in O-specific polysaccharide (OSP but not Vibrio polysaccharide (VPS. Finally, we demonstrate that ECM production by V. cholerae in response to ZAC-3 IgG was associated with bacterial resistant to a secondary complement-mediated attack. In summary, we propose that V. cholerae O1, upon encountering anti-LPS antibodies in the intestinal lumen, secretes an ECM (or O-antigen capsule possibly as a strategy to shield itself from additional host immune factors and to exit an otherwise inhospitable host environment.

  10. Fundamental studies on ADCC (antibody-dependent cell-mediated cytotoxicity) of human peripheral blood leukocytes using sheep red blood cells as target cells, and the effect of erythrophagocytosis

    International Nuclear Information System (INIS)

    Ichikawa, Yukinobu; Takaya, Masatoshi; Arimori, Shigeru

    1979-01-01

    We investigated antibody-dependent cell-mediated cytotoxicity (ADCC) of human peripheral blood leukocytes by using 51 Cr-labelled sheep red blood cells (SRBC) as target cells and anti-SRBC rabbit antibody. Lysis of SRBC was mediated by either human peripheral lymphoid cells or phagocytes (Monocytes and granulocytes). SRBC were useful as target cells in ADCC assay against human lymphoid cells, since decreased cytotoxic activity of phagocyte-contaminated crude lymphocyte fraction was recovered by elimination of contaminating phagocytes. The monocytes inhibited ADCC of lymphoid cells through phagocytosis of SRBC. This assay system may be useful for estimating not only Fc receptor-mediated cytotoxicity but also Fc receptor-mediated phagocytic activity of human peripheral blood leukocytes. (author)

  11. Protection by meningococcal outer membrane protein PorA-specific antibodies and a serogroup B capsular polysaccharide-specific antibody in complement-sufficient and C6-deficient infant rats

    NARCIS (Netherlands)

    Toropainen, Maija; Saarinen, Leena; Vidarsson, Gestur; Käyhty, Helena

    2006-01-01

    The relative contributions of antibody-induced complement-mediated bacterial lysis and antibody/complement-mediated phagocytosis to host immunity against meningococcal infections are currently unclear. Further, the in vivo effector functions of antibodies may vary depending on their specificity and

  12. [Limbic encephalitis with antibodies against intracellular antigens].

    Science.gov (United States)

    Morita, Akihiko; Kamei, Satoshi

    2010-04-01

    Limbic encephalitis is a paraneoplastic syndrome that is often associated with small cell lung cancer (SCLC), breast cancer, testicular tumors, teratoma, Hodgkin's lymphoma and thymoma. The common clinical manifestations of limbic encephalitis are subacute onset, cognitive dysfunction, seizures and psychiatric symptoms. Paraneoplastic neurological disorders are considered to occur because of cytotoxic T cell responses and antibodies against target neuronal proteins that are usually expressed by an underlying tumor. The main intracellular antigens related to limbic encephalitis are Hu, Ma2, and less frequently CV2/CRMP5 and amphiphysin. The anti-Hu antibody, which is involved in cerebellar degeneration and extensive or multifocal encephalomyelitis such as limbic encephalitis is closely associated with a history of smoking and SCLC. The anti-Ma2 antibody is associated with encephalitis of the limbic system, hypothalamus and brain-stem. For this reason, some patients with limbic encephalitis have sleep disorders (including REM sleep abnormalities), severe hypokinesis and gaze palsy in addition to limbic dysfunction. In men aged less than 50 years, anti-Ma2 antibody encephalitis is almost always associated with testicular germ-cell tumors that are occasionally difficult to detect. In older men and women, the most common tumors are non-SCLC and breast cancer. Limbic encephalitis associated with cell-surface antigens (e.g., voltage-gated potassium channels, NMDA receptors) is mediated by antibodies and often improves after a reduction in the antibody titer and after tumor resection. Patients with antibodies against intracellular antigens, except for those with anti-Ma2 antibodies and testicular tumors, are less responsive. Early diagnosis and treatment with immunotherapy, tumor resection or both are important for improving or stabilizing the condition of limbic encephalitis.

  13. Anti-Glycoprotein G Antibodies of Herpes Simplex Virus 2 Contribute to Complete Protection after Vaccination in Mice and Induce Antibody-Dependent Cellular Cytotoxicity and Complement-Mediated Cytolysis

    Directory of Open Access Journals (Sweden)

    Staffan Görander

    2014-11-01

    Full Text Available We investigated the role of antibodies against the mature portion of glycoprotein G (mgG-2 of herpes simplex virus 2 (HSV-2 in protective immunity after vaccination. Mice were immunized intramuscularly with mgG-2 and oligodeoxynucleotides containing two CpG motifs plus alum as adjuvant. All C57BL/6 mice survived and presented no genital or systemic disease. High levels of immunoglobulin G subclass 1 (IgG1 and IgG2 antibodies were detected and re-stimulated splenic CD4+ T cells proliferated and produced IFN-γ. None of the sera from immunized mice exhibited neutralization, while all sera exerted antibody-dependent cellular cytotoxicity (ADCC and complement-mediated cytolysis (ACMC activity. Passive transfer of anti-mgG-2 monoclonal antibodies, or immune serum, to naive C57BL/6 mice did not limit disease progression. Immunized B‑cell KO mice presented lower survival rate and higher vaginal viral titers, as compared with vaccinated B-cell KO mice after passive transfer of immune serum and vaccinated C57BL/6 mice. Sera from mice that were vaccinated subcutaneously and intranasally with mgG-2 presented significantly lower titers of IgG antibodies and lower ADCC and ACMC activity. We conclude that anti-mgG-2 antibodies were of importance to limit genital HSV‑2 infection. ADCC and ACMC activity are potentially important mechanisms in protective immunity, and could tentatively be evaluated in future animal vaccine studies and in clinical trials.

  14. High throughput screening for antibody induced complement-dependent cytotoxicity in early antibody discovery using homogeneous macroconfocal fluorescence imaging

    NARCIS (Netherlands)

    Gerritsen, Arnout F.; Bosch, Martijn; de Weers, Michel; van de Winkel, Jan G. J.; Parren, Paul W. H. I.

    2010-01-01

    Complement-dependent cytotoxicity (CDC) represents an important Fc-mediated effector function of antibodies and is a quality often sought in candidates for therapeutic antibody development in cancer. Antibodies inducing potent CDC are relatively rare as the ability to induce CDC is strongly

  15. Immunoglobulin G4: an odd antibody

    NARCIS (Netherlands)

    Aalberse, R. C.; Stapel, S. O.; Schuurman, J.; Rispens, T.

    2009-01-01

    Despite its well-known association with IgE-mediated allergy, IgG4 antibodies still have several poorly understood characteristics. IgG4 is a very dynamic antibody: the antibody is involved in a continuous process of half-molecules (i.e. a heavy and attached light-chain) exchange. This process, also

  16. Intramuscular Adeno-Associated Virus-Mediated Expression of Monoclonal Antibodies Provides 100% Protection Against Ebola Virus Infection in Mice.

    Science.gov (United States)

    van Lieshout, Laura P; Soule, Geoff; Sorensen, Debra; Frost, Kathy L; He, Shihua; Tierney, Kevin; Safronetz, David; Booth, Stephanie A; Kobinger, Gary P; Qiu, Xiangguo; Wootton, Sarah K

    2018-03-05

    The 2013-2016 West Africa outbreak demonstrated the epidemic potential of Ebola virus and highlighted the need for counter strategies. Monoclonal antibody (mAb)-based therapies hold promise as treatment options for Ebola virus infections. However, production of clinical-grade mAbs is labor intensive, and immunity is short lived. Conversely, adeno-associated virus (AAV)-mediated mAb gene transfer provides the host with a genetic blueprint to manufacture mAbs in vivo, leading to steady release of antibody over many months. Here we demonstrate that AAV-mediated expression of nonneutralizing mAb 5D2 or 7C9 confers 100% protection against mouse-adapted Ebola virus infection, while neutralizing mAb 2G4 was 83% protective. A 2-component cocktail, AAV-2G4/AAV-5D2, provided complete protection when administered 7 days prior to challenge and was partially protective with a 3-day lead time. Finally, AAV-mAb therapies provided sustained protection from challenge 5 months following AAV administration. AAV-mAb may be a viable alternative strategy for vaccination against emerging infectious diseases.

  17. Alterations of HIV-1 envelope phenotype and antibody-mediated neutralization by signal peptide mutations.

    Directory of Open Access Journals (Sweden)

    Chitra Upadhyay

    2018-01-01

    Full Text Available HIV-1 envelope glycoprotein (Env mediates virus attachment and entry into the host cells. Like other membrane-bound and secreted proteins, HIV-1 Env contains at its N terminus a signal peptide (SP that directs the nascent Env to the endoplasmic reticulum (ER where Env synthesis and post-translational modifications take place. SP is cleaved during Env biosynthesis but potentially influences the phenotypic traits of the Env protein. The Env SP sequences of HIV-1 isolates display high sequence variability, and the significance of such variability is unclear. We postulate that changes in the Env SP influence Env transport through the ER-Golgi secretory pathway and Env folding and/or glycosylation that impact on Env incorporation into virions, receptor binding and antibody recognition. We first evaluated the consequences of mutating the charged residues in the Env SP in the context of infectious molecular clone HIV-1 REJO.c/2864. Results show that three different mutations affecting histidine at position 12 affected Env incorporation into virions that correlated with reduction of virus infectivity and DC-SIGN-mediated virus capture and transmission. Mutations at positions 8, 12, and 15 also rendered the virus more resistant to neutralization by monoclonal antibodies against the Env V1V2 region. These mutations affected the oligosaccharide composition of N-glycans as shown by changes in Env reactivity with specific lectins and by mass spectrometry. Increased neutralization resistance and N-glycan composition changes were also observed when analogous mutations were introduced to another HIV-1 strain, JRFL. To the best of our knowledge, this is the first study showing that certain residues in the HIV-1 Env SP can affect virus neutralization sensitivity by modulating oligosaccharide moieties on the Env N-glycans. The HIV-1 Env SP sequences thus may be under selective pressure to balance virus infectiousness with virus resistance to the host antibody

  18. Enhanced CDC of B cell chronic lymphocytic leukemia cells mediated by rituximab combined with a novel anti-complement factor H antibody.

    Directory of Open Access Journals (Sweden)

    Mark T Winkler

    Full Text Available Rituximab therapy for B cell chronic lymphocytic leukemia (B-CLL has met with mixed success. Among several factors to which resistance can be attributed is failure to activate complement dependent cytotoxicity (CDC due to protective complement regulatory proteins, including the soluble regulator complement factor H (CFH. We hypothesized that rituximab killing of non-responsive B-CLL cells could be augmented by a novel human monoclonal antibody against CFH. The B cells from 11 patients with B-CLL were tested ex vivo in CDC assays with combinations of CFH monoclonal antibody, rituximab, and a negative control antibody. CDC of rituximab non-responsive malignant B cells from CLL patients could in some cases be augmented by the CFH monoclonal antibody. Antibody-mediated cytotoxicity of cells was dependent upon functional complement. In one case where B-CLL cells were refractory to CDC by the combination of rituximab plus CFH monoclonal antibody, additionally neutralizing the membrane complement regulatory protein CD59 allowed CDC to occur. Inhibiting CDC regulatory proteins such as CFH holds promise for overcoming resistance to rituximab therapy in B-CLL.

  19. Bispecific Antibody Pretargeting for Improving Cancer Imaging and Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Sharkey, Robert M.

    2005-02-04

    The main objective of this project was to evaluate pretargeting systems that use a bispecific antibody (bsMAb) to improve the detection and treatment of cancer. A bsMAb has specificity to a tumor antigen, which is used to bind the tumor, while the other specificity is to a peptide that can be radiolabeled. Pretargeting is the process by which the unlabeled bsMAb is given first, and after a sufficient time (1-2 days) is given for it to localize in the tumor and clear from the blood, a small molecular weight radiolabeled peptide is given. According to a dynamic imaging study using a 99mTc-labeled peptide, the radiolabeled peptide localizes in the tumor in less than 1 hour, with > 80% of it clearing from the blood and body within this same time. Tumor/nontumor targeting ratios that are nearly 50 times better than that with a directly radiolabeled Fab fragment have been observed (Sharkey et al., ''Signal amplification in molecular imaging by a multivalent bispecific nanobody'' submitted). The bsMAbs used in this project have been composed of 3 antibodies that will target antigens found in colorectal and pancreatic cancers (CEA, CSAp, and MUC1). For the ''peptide binding moiety'' of the bsMAb, we initially examined an antibody directed to DOTA, but subsequently focused on another antibody directed against a novel compound, HSG (histamine-succinyl-glycine).

  20. A simple vector system to improve performance and utilisation of recombinant antibodies

    Directory of Open Access Journals (Sweden)

    Vincent Karen J

    2006-12-01

    Full Text Available Abstract Background Isolation of recombinant antibody fragments from antibody libraries is well established using technologies such as phage display. Phage display vectors are ideal for efficient display of antibody fragments on the surface of bacteriophage particles. However, they are often inefficient for expression of soluble antibody fragments, and sub-cloning of selected antibody populations into dedicated soluble antibody fragment expression vectors can enhance expression. Results We have developed a simple vector system for expression, dimerisation and detection of recombinant antibody fragments in the form of single chain Fvs (scFvs. Expression is driven by the T7 RNA polymerase promoter in conjunction with the inducible lysogen strain BL21 (DE3. The system is compatible with a simple auto-induction culture system for scFv production. As an alternative to periplasmic expression, expression directly in the cytoplasm of a mutant strain with a more oxidising cytoplasmic environment (Origami 2™ (DE3 was investigated and found to be inferior to periplasmic expression in BL21 (DE3 cells. The effect on yield and binding activity of fusing scFvs to the N terminus of maltose binding protein (a solubility enhancing partner, bacterial alkaline phosphatase (a naturally dimeric enzymatic reporter molecule, or the addition of a free C-terminal cysteine was determined. Fusion of scFvs to the N-terminus of maltose binding protein increased scFv yield but binding activity of the scFv was compromised. In contrast, fusion to the N-terminus of bacterial alkaline phosphatase led to an improved performance. Alkaline phosphatase provides a convenient tag allowing direct enzymatic detection of scFv fusions within crude extracts without the need for secondary reagents. Alkaline phosphatase also drives dimerisation of the scFv leading to an improvement in performance compared to monovalent constructs. This is illustrated by ELISA, western blot and

  1. 9th annual European Antibody Congress, November 11-13, 2013, Geneva, Switzerland.

    Science.gov (United States)

    Reichert, Janice M; Beck, Alain; Lugovskoy, Alexey A; Wurch, Thierry; Coats, Steven; Brezski, Randall J

    2014-01-01

    The annual European Antibody Congress (EAC) has traditionally been the key event for updates on critical scientific advances in the antibody field, and 2013 was no exception. Organized by Terrapinn, the well-attended meeting featured presentations on considerations for developing antibodies and antibody-like therapeutics, with separate tracks for antibody-drug conjugates, naked antibodies, and multispecific antibodies or protein scaffolds. The overall focus of the EAC was current approaches to enhance the functionality of therapeutic antibodies or other targeted proteins, with the ultimate goal being improvement of the safety and efficacy of the molecules as treatments for cancer, immune-mediated disorders and other diseases. Roundtable discussion sessions gave participants opportunities to engage in group discussions with industry leaders from companies such as Genmab, Glenmark Pharmaceuticals, MedImmune, Merrimack Pharmaceuticals, and Pierre Fabre. As the 2013 EAC was co-located with the World Biosimilar Congress, participants also received an update on European Medicines Agency guidelines and thoughts on the future direction and development of biosimilar antibodies in the European Union.

  2. SUCCESSFUL APPLICATION OF PERIPHERAL VENO-ARTERIAL EXTRACORPOREAL MEMBRANE OXYGENATION FOR CARDIAC ALLOGRAFT ANTIBODY-MEDIATED REJECTION WITH SEVERE HEMODYNAMIC COMPROMISE

    Directory of Open Access Journals (Sweden)

    V. N. Poptsov

    2015-01-01

    Full Text Available Introduction. Acute antibody-mediated rejection (AMR is one of the severe complications of early and late period after heart transplantation (HT. Only few case reports and studies presented of mechanical circulatory support (MCS application for refractory acute rejection causing hemodynamic compromise. Aim. We report the case of a woman with cardiogenic shock caused by severe AMR that was successfully treatment by peripheral venoarterial extracorporeal membrane oxygenation (VA ECMO. Material and methods. In december 2014, a 60-year-old woman with dilated cardiomyopathy was operated for HT. The patient had a good initial cardiac allograft function and no and was discharged from ICU on the 4th day after HT. 1st endomyocardial biopsy (EMB (the 7th day after HT showed absence of acute cellular and antibody-mediated rejection. On the 11th day after HT patient aggravated and presented clinical signs of life-threatening acute cardiac allograft dysfunction: arterial blood pressure 78/49/38 mm Hg, HR 111 in min, CVP 20 mm Hg, PAP 47/34/25 mm Hg, PCWP 25 mm Hg, CI 1.5 l/min/m2, adrenalin 110 ng/kg/min, dopamine 15 mcg/kg/min. ECG showed impairment of systolic left (LVEF 25% and right (RVEF 15% ventricle function, left and right ventricle diffuse hypokinesis, thickness of IVS, LV and RV wall 1.7, 1.4 and 0.8 cm, tricuspid and mitral valve regurgitation 2–3 degrees. EMB presented AMR. In conscience peripheral VA ECMO was installed. We used peripheral transcutaneous cannulation technique via femoral vessels – arterial cannula 15 F, venous cannula – 23 F, vascular catheter 14 G for anterograde leg’s perfusion. ACT 130–150 sec. AMR therapy included: methylprednisolon pulse-therapy (10 mg/kg for 5 day, IgG, plasmapheresis (No 7, rituximab. Results. Under MCS by VA ECMO we noted quick improvement of hemodynamic, metabolic homeostasis and organ functions. On the 6th day of VA ECMO (blood flow 1.8 l/min: arterial blood pressure 133/81/54 mm Hg, CVP 5 mm

  3. CEA/CD3-bispecific T cell-engaging (BiTE) antibody-mediated T lymphocyte cytotoxicity maximized by inhibition of both PD1 and PD-L1.

    Science.gov (United States)

    Osada, Takuya; Patel, Sandip P; Hammond, Scott A; Osada, Koya; Morse, Michael A; Lyerly, H Kim

    2015-06-01

    Bispecific T cell-engaging (BiTE) antibodies recruit polyclonal cytotoxic T cells (CTL) to tumors. One such antibody is carcinoembryonic antigen (CEA) BiTE that mediates T cell/tumor interaction by simultaneously binding CD3 expressed by T cells and CEA expressed by tumor cells. A widely operative mechanism for mitigating cytotoxic T cell-mediated killing is the interaction of tumor-expressed PD-L1 with T cell-expressed PD-1, which may be partly reversed by PD-1/PD-L1 blockade. We hypothesized that PD-1/PD-L1 blockade during BiTE-mediated T cell killing would enhance CTL function. Here, we determined the effects of PD-1 and PD-L1 blockade during initial T cell-mediated killing of CEA-expressing human tumor cell lines in vitro, as well as subsequent T cell-mediated killing by T lymphocytes that had participated in tumor cell killing. We observed a rapid upregulation of PD-1 expression and diminished cytolytic function of T cells after they had engaged in CEA BiTE-mediated killing of tumors. T cell cytolytic activity in vitro could be maximized by administration of anti-PD-1 or anti-PD-L1 antibodies alone or in combination if applied prior to a round of T cell killing, but T cell inhibition could not be fully reversed by this blockade once the T cells had killed tumor. In conclusion, our findings demonstrate that dual blockade of PD-1 and PD-L1 maximizes T cell killing of tumor directed by CEA BiTE in vitro, is more effective if applied early, and provides a rationale for clinical use.

  4. Neuronal surface antigen antibodies in limbic encephalitis

    Science.gov (United States)

    Graus, F; Saiz, A; Lai, M; Bruna, J; López, F; Sabater, L; Blanco, Y; Rey, M J.; Ribalta, T; Dalmau, J

    2008-01-01

    Objective: To report the frequency and type of antibodies against neuronal surface antigens (NSA-ab) in limbic encephalitis (LE). Methods: Analysis of clinical features, neuropathologic findings, and detection of NSA-ab using immunochemistry on rat tissue and neuronal cultures in a series of 45 patients with paraneoplastic (23) or idiopathic (22) LE. Results: NSA-ab were identified in 29 patients (64%; 12 paraneoplastic, 17 idiopathic). Thirteen patients had voltage-gated potassium channels (VGKC)-ab, 11 novel NSA (nNSA)-ab, and 5 NMDA receptor (NMDAR)-ab. nNSA-ab did not identify a common antigen and were more frequent in paraneoplastic than idiopathic LE (39% vs 9%; p = 0.03). When compared with VGKC-ab or NMDAR-ab, the nNSA associated more frequently with intraneuronal antibodies (11% vs 73%; p = 0.001). Of 12 patients (9 nNSA-ab, 2 VGKC-ab, 1 NMDAR-ab) with paraneoplastic LE and NSA-ab, concomitant intraneuronal antibodies occurred in 9 (75%). None of these 12 patients improved with immunotherapy. The autopsy of three of them showed neuronal loss, microgliosis, and cytotoxic T cell infiltrates in the hippocampus and amygdala. These findings were compatible with a T-cell mediated neuronal damage. In contrast, 13 of 17 (76%) patients with idiopathic LE and NSA-ab (8 VGKC-ab, 4 NMDAR-ab, 1 nNSA-ab) and 1 of 5 (20%) without antibodies had clinical improvement (p = 0.04). Conclusions: In paraneoplastic limbic encephalitis (LE), novel antibodies against neuronal surface antigens (nNSA-ab) occur frequently, coexist with antibodies against intracellular antigens, and these cases are refractory to immunotherapy. In idiopathic LE, the likelihood of improvement is significantly higher in patients with NSA-ab than in those without antibodies. GLOSSARY GAD = glutamic acid decarboxylase; LE = limbic encephalitis; NMDAR = N-methyl-D-aspartate receptor; NSA = neuronal surface antigens; nNSA = novel NSA; SCLC = small-cell lung cancer; VGKC = voltage-gated potassium channels

  5. Soluble CD30 in patients with antibody-mediated rejection of the kidney allograft.

    Science.gov (United States)

    Slavcev, Antonij; Honsova, Eva; Lodererova, Alena; Pavlova, Yelena; Sajdlova, Helena; Vitko, Stefan; Skibova, Jelena; Striz, Ilja; Viklicky, Ondrej

    2007-07-01

    The aim of our retrospective study was to evaluate the clinical significance of measurement of the soluble CD30 (sCD30) molecule for the prediction of antibody-mediated (humoral) rejection (HR). Sixty-two kidney transplant recipients (thirty-one C4d-positive and thirty-one C4d-negative patients) were included into the study. Soluble CD30 levels were evaluated before transplantation and during periods of graft function deterioration. The median concentrations of the sCD30 molecule were identical in C4d-positive and C4d-negative patients before and after transplantation (65.5 vs. 65.0 and 28.2 vs. 36.0 U/ml, respectively). C4d+ patients who developed DSA de novo had a tendency to have higher sCD30 levels before transplantation (80.7+/-53.6 U/ml, n=8) compared with C4d-negative patients (65.0+/-33.4 U/ml, n=15). Soluble CD30 levels were evaluated as positive and negative (>or=100 U/ml and sCD30 estimation with regard to finding C4d deposits in peritubular capillaries were determined. The sensitivity of sCD30+ testing was generally below 40%, while the specificity of the test, i.e. the likelihood that if sCD30 testing is negative, C4d deposits would be absent, was 82%. C4d+ patients who developed DSA de novo were evaluated separately; the specificity of sCD30 testing for the incidence of HR in this cohort was 86%. We could not confirm in our study that high sCD30 levels (>or=100 U/ml) might be predictive for the incidence of HR. Negative sCD30 values might be however helpful for identifying patients with a low risk for development of DSA and antibody-mediated rejection.

  6. Donor-specific anti-HLA antibodies with antibody-mediated rejection and long-term outcomes following heart transplantation.

    Science.gov (United States)

    Clerkin, Kevin J; Farr, Maryjane A; Restaino, Susan W; Zorn, Emmanuel; Latif, Farhana; Vasilescu, Elena R; Marboe, Charles C; Colombo, Paolo C; Mancini, Donna M

    2017-05-01

    Donor-specific anti-HLA antibodies (DSA) are common after heart transplantation and are associated with rejection, cardiac allograft vasculopathy, and mortality. A noninvasive diagnostic test for pathologic antibody-mediated rejection (pAMR) does not exist. From January 1, 2010, through August 31, 2013, 221 consecutive adult patients underwent heart transplantation and were followed through October 1, 2015. The primary objective was to determine whether the presence of DSA could detect AMR at the time of pathologic diagnosis. Secondary analyses included association of DSA (stratified by major histocompatibility complex class and de novo status) during AMR with new graft dysfunction, graft loss (mortality or retransplantation), and development of cardiac allograft vasculopathy. During the study period, 69 patients (31.2%) had DSA (24% had de novo DSA), and there were 74 episodes of pAMR in 38 patients. Sensitivity of DSA at any mean fluorescence intensity to detect concurrent pAMR was only 54.3%. The presence of any DSA during pAMR increased the odds of graft dysfunction (odds ratio = 5.37; 95% confidence interval [CI], 1.34-21.47; p = 0.018), adjusting for age, sex, and timing of AMR. Circulating class II DSA after transplantation increased risk of future pAMR (hazard ratio = 2.97; 95% CI, 1.31-6.73; p = 0.009). Patients who developed de novo class II DSA had 151% increased risk of graft loss (contingent on 30-day survival) compared with patients who did not have DSA (95% CI, 1.11-5.69; p = 0.027). DSA were inadequate to diagnose pAMR. Class II DSA provided prognostic information regarding future pAMR, graft dysfunction with pAMR, and graft loss. Copyright © 2017 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  7. Antibody Responses with Fc-Mediated Functions after Vaccination of HIV-Infected Subjects with Trivalent Influenza Vaccine

    DEFF Research Database (Denmark)

    Kristensen, Anne B; Lay, William N; Ana-Sosa-Batiz, Fernanda

    2016-01-01

    to immunize this at-risk group. IMPORTANCE: Infection with HIV is associated with increasing disease severity following influenza infections, and annual influenza vaccinations are recommended for this target group. However, HIV-infected individuals respond relatively poorly to vaccination compared to healthy......This study seeks to assess the ability of seasonal trivalent inactivated influenza vaccine (TIV) to induce nonneutralizing antibodies (Abs) with Fc-mediated functions in HIV-uninfected and HIV-infected subjects. Functional influenza-specific Ab responses were studied in 30 HIV-negative and 27 HIV......-positive subjects immunized against seasonal influenza. All 57 subjects received the 2015 TIV. Fc-mediated antihemagglutinin (anti-HA) Ab activity was measured in plasma before and 4 weeks after vaccination using Fc-receptor-binding assays, NK cell activation assays, and phagocytosis assays. At baseline, the HIV...

  8. A recombinant, fully human monoclonal antibody with antitumor activity constructed from phage-displayed antibody fragments

    NARCIS (Netherlands)

    Huls, GA; Heijnen, IAFM; Cuomo, ME; Koningsberger, JC; Boel, E; de Vries, ARV; Loyson, SAJ; Helfrich, W; Henegouwen, GPV; van Meijer, M; de Kruif, J; Logtenberg, T

    A single-chain Fv antibody fragment specific for the tumor-associated Ep-CAM molecule was isolated from a semisynthetic phage display library and converted into an intact, fully human IgG1 monoclonal antibody (huMab), The purified huMab had an affinity of 5 nM and effectively mediated tumor cell

  9. Immunogenicity of anti-tumor necrosis factor antibodies-toward improved methods of anti-antibody measurement.

    Science.gov (United States)

    Aarden, Lucien; Ruuls, Sigrid R; Wolbink, Gertjan

    2008-08-01

    To date, millions of people have been treated with therapeutic monoclonal antibodies (TmAbs) for various indications. It is becoming increasingly clear that TmAbs can be immunogenic, which may reduce efficacy or induce adverse effects. Over the years, the importance of antibody formation has been questioned and sometimes minimized, as few antibody responses to TmAbs (HACA or HAHA) were reported. However, the methods to detect and quantify such antibodies used in the past have been problematic. Only recently, methods have been developed that have adequate sensitivity and are not seriously disturbed by false-positive reactions caused by rheumatoid factors, natural antibodies to Fab or F(ab')2 fragments, or Fc interactions of IgG4. The large number of treated patients, in combination with these new assays, presents a unique opportunity to study the anti-antibody immune response in man, possibly allowing us to manipulate immunogenicity in the future.

  10. Intravenous immunoglobulin prevents murine antibody-mediated acute lung injury at the level of neutrophil reactive oxygen species (ROS production.

    Directory of Open Access Journals (Sweden)

    John W Semple

    Full Text Available Transfusion-related acute lung injury (TRALI is a leading cause of transfusion-associated mortality that can occur with any type of transfusion and is thought to be primarily due to donor antibodies activating pulmonary neutrophils in recipients. Recently, a large prospective case controlled clinical study of cardiac surgery patients demonstrated that despite implementation of male donors, a high incidence of TRALI still occurred and suggested a need for additional interventions in susceptible patient populations. To examine if intravenous immunoglobulin (IVIg may be effective, a murine model of antibody-mediated acute lung injury that approximates human TRALI was examined. When BALB/c mice were injected with the anti-major histocompatibility complex class I antibody 34-1-2s, mild shock (reduced rectal temperature and respiratory distress (dyspnea were observed and pre-treatment of the mice with 2 g/kg IVIg completely prevented these symptoms. To determine IVIg's usefulness to affect severe lung damage, SCID mice, previously shown to be hypersensitive to 34-1-2s were used. SCID mice treated with 34-1-2s underwent severe shock, lung damage (increased wet/dry ratios and 40% mortality within 2 hours. Treatment with 2 g/kg IVIg 18 hours before 34-1-2s administration completely protected the mice from all adverse events. Treatment with IVIg after symptoms began also reduced lung damage and mortality. While the prophylactic IVIg administration did not affect 34-1-2s-induced pulmonary neutrophil accumulation, bone marrow-derived neutrophils from the IVIg-treated mice displayed no spontaneous ROS production nor could they be stimulated in vitro with fMLP or 34-1-2s. These results suggest that IVIg prevents murine antibody-mediated acute lung injury at the level of neutrophil ROS production and thus, alleviating tissue damage.

  11. Humanised IgG1 antibody variants targeting membrane-bound carcinoembryonic antigen by antibody-dependent cellular cytotoxicity and phagocytosis.

    Science.gov (United States)

    Ashraf, S Q; Umana, P; Mössner, E; Ntouroupi, T; Brünker, P; Schmidt, C; Wilding, J L; Mortensen, N J; Bodmer, W F

    2009-11-17

    The effect of glycoengineering a membrane specific anti-carcinoembryonic antigen (CEA) (this paper uses the original term CEA for the formally designated CEACAM5) antibody (PR1A3) on its ability to enhance killing of colorectal cancer (CRC) cell lines by human immune effector cells was assessed. In vivo efficacy of the antibody was also tested. The antibody was modified using EBNA cells cotransfected with beta-1,4-N-acetylglucosaminyltransferase III and the humanised hPR1A3 antibody genes. The resulting alteration of the Fc segment glycosylation pattern enhances the antibody's binding affinity to the FcgammaRIIIa receptor on human immune effector cells but does not alter the antibody's binding capacity. Antibody-dependent cellular cytotoxicity (ADCC) is inhibited in the presence of anti-FcgammaRIII blocking antibodies. This glycovariant of hPR1A3 enhances ADCC 10-fold relative to the parent unmodified antibody using either unfractionated peripheral blood mononuclear or natural killer (NK) cells and CEA-positive CRC cells as targets. NK cells are far more potent in eliciting ADCC than either freshly isolated monocytes or granulocytes. Flow cytometry and automated fluorescent microscopy have been used to show that both versions of hPR1A3 can induce antibody-dependent cellular phagocytosis (ADCP) by monocyte-derived macrophages. However, the glycovariant antibody did not mediate enhanced ADCP. This may be explained by the relatively low expression of FcgammaRIIIa on cultured macrophages. In vivo studies show the efficacy of glycoengineered humanised IgG1 PR1A3 in significantly improving survival in a CRC metastatic murine model. The greatly enhanced in vitro ADCC activity of the glycoengineered version of hPR1A3 is likely to be clinically beneficial.

  12. Complement-mediated bactericidal activity of anti-factor H binding protein monoclonal antibodies against the meningococcus relies upon blocking factor H binding.

    Science.gov (United States)

    Giuntini, Serena; Reason, Donald C; Granoff, Dan M

    2011-09-01

    Binding of the complement-downregulating protein factor H (fH) to the surface of the meningococcus is important for survival of the organism in human serum. The meningococcal vaccine candidate factor H binding protein (fHbp) is an important ligand for human fH. While some fHbp-specific monoclonal antibodies (MAbs) block binding of fH to fHbp, the stoichiometry of blocking in the presence of high serum concentrations of fH and its effect on complement-mediated bactericidal activity are unknown. To investigate this question, we constructed chimeric antibodies in which the human IgG1 constant region was paired with three murine fHbp-specific binding domains designated JAR 3, JAR 5, and MAb502. By surface plasmon resonance, the association rates for binding of all three MAbs to immobilized fHbp were >50-fold higher than that for binding of fH to fHbp, and the MAb dissociation rates were >500-fold lower than that for fH. While all three MAbs elicited similar C1q-dependent C4b deposition on live bacteria (classical complement pathway), only those antibodies that inhibited binding of fH to fHbp (JAR 3 and JAR 5) had bactericidal activity with human complement. MAb502, which did not inhibit fH binding, had complement-mediated bactericidal activity only when tested with fH-depleted human complement. When an IgG1 anti-fHbp MAb binds to sparsely exposed fHbp on the bacterial surface, there appears to be insufficient complement activation for bacteriolysis unless fH binding also is inhibited. The ability of fHbp vaccines to elicit protective antibodies, therefore, is likely to be enhanced if the antibody repertoire is of high avidity and includes fH-blocking activity.

  13. Improved Metabolic Control in Diabetes, HSP60, and Proinflammatory Mediators

    Directory of Open Access Journals (Sweden)

    Claudio Blasi

    2012-01-01

    Full Text Available The diabetes-atherosclerosis relationship remains to be fully defined. Repeated prolonged hyperglycemia, increased ROS production and endothelial dysfunction are important factors. One theory is that increased blood levels of heat shock protein (HSP60 are proinflammatory, through activation of innate immunity, and contribute to the progression of vascular disease. It was hypothesized that improvement of diabetes control in patients presenting with metabolic syndrome would lower HSP60, and anti-HSP60 antibody levels and decrease inflammatory markers. Paired sera of 17 Italian patients, before and after intensive treatment, were assayed for cytokines, HSP60 and anti-HSP60 antibodies. As expected, intensive treatment was associated with a decrease in HgbA1C (P<0.001 and BMI (P<0.001. After treatment, there was a significant decrease in IL-6 (P<0.05. HSP60 levels were before treatment −6.9+1.9, after treatment −7.1+2.0 ng/mL (P=ns. Overall HSP60 concentrations were lower than published reports. Anti-HSP60 antibody titers were high and did not decrease with treatment. In conclusion, improvement of diabetic control did not alter HSP60 concentrations or antiHSP60 antibody titers, but led to a reduction of IL-6 levels.

  14. Fusion Peptide Improves Stability and Bioactivity of Single Chain Antibody against Rabies Virus.

    Science.gov (United States)

    Xi, Hualong; Zhang, Kaixin; Yin, Yanchun; Gu, Tiejun; Sun, Qing; Shi, Linqing; Zhang, Renxia; Jiang, Chunlai; Kong, Wei; Wu, Yongge

    2017-04-28

    The combination of rabies immunoglobulin (RIG) with a vaccine is currently effective against rabies infections, but improvements are needed. Genetic engineering antibody technology is an attractive approach for developing novel antibodies to replace RIG. In our previous study, a single-chain variable fragment, scFv57R, against rabies virus glycoprotein was constructed. However, its inherent weak stability and short half-life compared with the parent RIG may limit its diagnostic and therapeutic application. Therefore, an acidic tail of synuclein (ATS) derived from the C-terminal acidic tail of human alpha-synuclein protein was fused to the C-terminus of scFv57R in order to help it resist adverse stress and improve the stability and halflife. The tail showed no apparent effect on the preparation procedure and affinity of the protein, nor did it change the neutralizing potency in vitro. In the ELISA test of molecular stability, the ATS fusion form of the protein, scFv57R-ATS, showed an increase in thermal stability and longer half-life in serum than scFv57R. The protection against fatal rabies virus challenge improved after fusing the tail to the scFv, which may be attributed to the improved stability. Thus, the ATS fusion approach presented here is easily implemented and can be used as a new strategy to improve the stability and half-life of engineered antibody proteins for practical applications.

  15. Chelate chase of radiopharmaceuticals reversibly bound to monoclonal antibodies improves dosimetry

    International Nuclear Information System (INIS)

    Goodwin, D.A.; Smith, S.I.; Meares, C.F.; David, G.S.; McTigue, M.; Finston, R.A.

    1986-01-01

    One hundred micrograms of monoclonal antibody (MoAb) CHA 255 with a binding constant Kb of 4 x 10 9 was complexed with indium-111 labeled BLEDTA II, GLEDTA IV, benzyl EDTA, and an EDTA conjugate of Fab. The 24-hour tumor and organ distribution in BALB/c mice bearing KHJJ tumors was studied for each compound alone, the antibody complex, and 3 hours following a chelate chase of the antibody complex. Whole-body biological half-life was measured for 7 days with and without a chelate chase for each antibody complex. The 24-hour whole-body counts dropped 20-60% within 3 hours of administering the chelate chase. Blood concentration fell over 89% within 3 hours of administering the chase and there was a decrease in concentration in all organs, except the kidneys, of 10 to 85%. Theoretical equivalent human doses were calculated from the 24-hour organ concentrations, effective half-life, and MIRD 11 S values (absorbed dose per cumulated activity). Liver and spleen were the target organs, with the dose ranging from 0.50 to 3.91 rads per millicurie. The reduction in organ radiation dose varied up to 95% following the chelate chase. Rapid selective renal clearance of chelate labeled radiopharmaceuticals by competitive inhibition (chelate chase) of their reversible binding to monoclonal antibodies, greatly improves the radiation dosimetry of tumor imaging agents. 28 references, 5 figures, 5 tables

  16. Targeting of phage particles towards endothelial cells by antibodies selected through a multi-parameter selection strategy.

    Science.gov (United States)

    Mandrup, Ole A; Lykkemark, Simon; Kristensen, Peter

    2017-02-10

    One of the hallmarks of cancer is sustained angiogenesis. Here, normal endothelial cells are activated, and their formation of new blood vessels leads to continued tumour growth. An improved patient condition is often observed when angiogenesis is prevented or normalized through targeting of these genomically stable endothelial cells. However, intracellular targets constitute a challenge in therapy, as the agents modulating these targets have to be delivered and internalized specifically to the endothelial cells. Selection of antibodies binding specifically to certain cell types is well established. It is nonetheless a challenge to ensure that the binding of antibodies to the target cell will mediate internalization. Previously selection of such antibodies has been performed targeting cancer cell lines; most often using either monovalent display or polyvalent display. In this article, we describe selections that isolate internalizing antibodies by sequential combining monovalent and polyvalent display using two types of helper phages, one which increases display valence and one which reduces background. One of the selected antibodies was found to mediate internalization into human endothelial cells, although our results confirms that the single stranded nature of the DNA packaged into phage particles may limit applications aimed at targeting nucleic acids in mammalian cells.

  17. Acute liver allograft antibody-mediated rejection: an inter-institutional study of significant histopathological features.

    Science.gov (United States)

    O'Leary, Jacqueline G; Michelle Shiller, S; Bellamy, Christopher; Nalesnik, Michael A; Kaneku, Hugo; Jennings, Linda W; Isse, Kumiko; Terasaki, Paul I; Klintmalm, Göran B; Demetris, Anthony J

    2014-10-01

    Acute antibody-mediated rejection (AMR) occurs in a small minority of sensitized liver transplant recipients. Although histopathological characteristics have been described, specific features that could be used (1) to make a generalizable scoring system and (2) to trigger a more in-depth analysis are needed to screen for this rare but important finding. Toward this goal, we created training and validation cohorts of putative acute AMR and control cases from 3 high-volume liver transplant programs; these cases were evaluated blindly by 4 independent transplant pathologists. Evaluations of hematoxylin and eosin (H&E) sections were performed alone without knowledge of either serum donor-specific human leukocyte antigen alloantibody (DSA) results or complement component 4d (C4d) stains. Routine histopathological features that strongly correlated with severe acute AMR included portal eosinophilia, portal vein endothelial cell hypertrophy, eosinophilic central venulitis, central venulitis severity, and cholestasis. Acute AMR inversely correlated with lymphocytic venulitis and lymphocytic portal inflammation. These and other characteristics were incorporated into models created from the training cohort alone. The final acute antibody-mediated rejection score (aAMR score)--the sum of portal vein endothelial cell hypertrophy, portal eosinophilia, and eosinophilic venulitis divided by the sum of lymphocytic portal inflammation and lymphocytic venulitis--exhibited a strong correlation with severe acute AMR in the training cohort [odds ratio (OR) = 2.86, P  1.75 (sensitivity = 34%, specificity = 86%) and another that optimized sensitivity at a score > 1.0 (sensitivity = 81%, specificity = 71%). In conclusion, the routine histopathological features of the aAMR score can be used to screen patients for acute AMR via routine H&E staining of indication liver transplant biopsy samples; however, a definitive diagnosis requires substantiation by DSA testing

  18. A generalized quantitative antibody homeostasis model: maintenance of global antibody equilibrium by effector functions.

    Science.gov (United States)

    Prechl, József

    2017-11-01

    The homeostasis of antibodies can be characterized as a balanced production, target-binding and receptor-mediated elimination regulated by an interaction network, which controls B-cell development and selection. Recently, we proposed a quantitative model to describe how the concentration and affinity of interacting partners generates a network. Here we argue that this physical, quantitative approach can be extended for the interpretation of effector functions of antibodies. We define global antibody equilibrium as the zone of molar equivalence of free antibody, free antigen and immune complex concentrations and of dissociation constant of apparent affinity: [Ab]=[Ag]=[AbAg]= K D . This zone corresponds to the biologically relevant K D range of reversible interactions. We show that thermodynamic and kinetic properties of antibody-antigen interactions correlate with immunological functions. The formation of stable, long-lived immune complexes correspond to a decrease of entropy and is a prerequisite for the generation of higher-order complexes. As the energy of formation of complexes increases, we observe a gradual shift from silent clearance to inflammatory reactions. These rules can also be applied to complement activation-related immune effector processes, linking the physicochemical principles of innate and adaptive humoral responses. Affinity of the receptors mediating effector functions shows a wide range of affinities, allowing the continuous sampling of antibody-bound antigen over the complete range of concentrations. The generation of multivalent, multicomponent complexes triggers effector functions by crosslinking these receptors on effector cells with increasing enzymatic degradation potential. Thus, antibody homeostasis is a thermodynamic system with complex network properties, nested into the host organism by proper immunoregulatory and effector pathways. Maintenance of global antibody equilibrium is achieved by innate qualitative signals modulating a

  19. Using an improved phagocytosis assay to evaluate the effect of HIV on specific antibodies to pregnancy-associated malaria.

    Science.gov (United States)

    Ataíde, Ricardo; Hasang, Wina; Wilson, Danny W; Beeson, James G; Mwapasa, Victor; Molyneux, Malcolm E; Meshnick, Steven R; Rogerson, Stephen J

    2010-05-25

    Pregnant women residing in malaria endemic areas are highly susceptible to Plasmodium falciparum malaria, particularly during their first pregnancy, resulting in low birth weight babies and maternal anaemia. This susceptibility is associated with placental sequestration of parasitised red blood cells expressing pregnancy-specific variant surface antigens. Acquisition of antibodies against these variant surface antigens may protect women and their offspring. Functions of such antibodies may include prevention of placental sequestration or opsonisation of parasitised cells for phagocytic clearance. Here we report the development and optimisation of a new high-throughput flow cytometry-based phagocytosis assay using undifferentiated Thp-1 cells to quantitate the amount of opsonizing antibody in patient sera, and apply this assay to measure the impact of HIV on the levels of antibodies to a pregnancy malaria-associated parasite line in a cohort of Malawian primigravid women. The assay showed high reproducibility, with inter-experimental correlation of r(2) = 0.99. In primigravid women, concurrent malaria infection was associated with significantly increased antibodies, whereas HIV decreased the ability to acquire opsonising antibodies (Mann-Whitney ranksum: p = 0.013). This decrease was correlated with HIV-induced immunosuppression, with women with less than 350 x 10(6) CD4+ T- cells/L having less opsonising antibodies (coef: -11.95,P = 0.002). Levels of antibodies were not associated with protection from low birth weight or anaemia. This flow cytometry-based phagocytosis assay proved to be efficient and accurate for the measurement of Fc-receptor mediated phagocytosis-inducing antibodies in large cohorts. HIV was found to affect mainly the acquisition of antibodies to pregnancy-specific malaria in primigravidae. Further studies of the relationship between opsonising antibodies to malaria in pregnancy and HIV are indicated.

  20. Identification of a novel myositis-associated antibody directed against cortactin.

    Science.gov (United States)

    Labrador-Horrillo, Moisés; Martínez, Maria Angeles; Selva-O'Callaghan, Albert; Trallero-Araguás, Ernesto; Grau-Junyent, Josep M; Vilardell-Tarrés, Miquel; Juarez, Candido

    2014-10-01

    The aim of this study is to describe a novel myositis-associated autoantibody (anti-cortactin antibody) and assess related clinical and immunological manifestations and its clinical significance. Adult patients with myositis (dermatomyositis, polymyositis, immune-mediated necrotizing myopathy, and inclusion body myositis), as well as patients with other autoimmune diseases and non-inflammatory myopathies were analyzed for the presence of anti-cortactin antibody using in-house developed ELISA and immunoblotting techniques with a commercial source of purified cortactin. The cut-off for positive status was determined in a group of healthy volunteers. Antibody against cortactin was positive in 7/34 (20%) polymyositis patients, 9/117 (7.6%) dermatomyositis, 2/7 (26%) immune-mediated necrotizing myopathy, and none of the 4 patients with inclusion body myositis. The antibody also tested positive in 3/101 patients with other autoimmune diseases (2 systemic sclerosis and 1 systemic lupus erythematosus), and in 1/29 patients with non-inflammatory myopathy. No relevant association with specific clinical features was found in patients with these antibodies. Anti-cortactin antibody was more frequently positive in patients with polymyositis and immune-mediated necrotizing myopathy than in the remaining myositis patients, and was the only myositis autoantibody found in sera of 3 patients from these groups. Our data indicate that cortactin is a novel target antigen in patients with autoimmune diseases, especially patients with polymyositis or immune-mediated necrotizing myopathy. Anti-cortactin can be considered a new myositis-associated antibody. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Microneedle-mediated immunization of an adenovirus-based malaria vaccine enhances antigen-specific antibody immunity and reduces anti-vector responses compared to the intradermal route.

    Science.gov (United States)

    Carey, John B; Vrdoljak, Anto; O'Mahony, Conor; Hill, Adrian V S; Draper, Simon J; Moore, Anne C

    2014-08-21

    Substantial effort has been placed in developing efficacious recombinant attenuated adenovirus-based vaccines. However induction of immunity to the vector is a significant obstacle to its repeated use. Here we demonstrate that skin-based delivery of an adenovirus-based malaria vaccine, HAdV5-PyMSP1₄₂, to mice using silicon microneedles induces equivalent or enhanced antibody responses to the encoded antigen, however it results in decreased anti-vector responses, compared to intradermal delivery. Microneedle-mediated vaccine priming and resultant induction of low anti-vector antibody titres permitted repeated use of the same adenovirus vaccine vector. This resulted in significantly increased antigen-specific antibody responses in these mice compared to ID-treated mice. Boosting with a heterologous vaccine; MVA-PyMSP1₄₂ also resulted in significantly greater antibody responses in mice primed with HAdV5-PyMSP1₄₂ using MN compared to the ID route. The highest protection against blood-stage malaria challenge was observed when a heterologous route of immunization (MN/ID) was used. Therefore, microneedle-mediated immunization has potential to both overcome some of the logistic obstacles surrounding needle-and-syringe-based immunization as well as to facilitate the repeated use of the same adenovirus vaccine thereby potentially reducing manufacturing costs of multiple vaccines. This could have important benefits in the clinical ease of use of adenovirus-based immunization strategies.

  2. Microneedle-mediated immunization of an adenovirus-based malaria vaccine enhances antigen-specific antibody immunity and reduces anti-vector responses compared to the intradermal route

    Science.gov (United States)

    Carey, John B.; Vrdoljak, Anto; O'Mahony, Conor; Hill, Adrian V. S.; Draper, Simon J.; Moore, Anne C.

    2014-01-01

    Substantial effort has been placed in developing efficacious recombinant attenuated adenovirus-based vaccines. However induction of immunity to the vector is a significant obstacle to its repeated use. Here we demonstrate that skin-based delivery of an adenovirus-based malaria vaccine, HAdV5-PyMSP142, to mice using silicon microneedles induces equivalent or enhanced antibody responses to the encoded antigen, however it results in decreased anti-vector responses, compared to intradermal delivery. Microneedle-mediated vaccine priming and resultant induction of low anti-vector antibody titres permitted repeated use of the same adenovirus vaccine vector. This resulted in significantly increased antigen-specific antibody responses in these mice compared to ID-treated mice. Boosting with a heterologous vaccine; MVA-PyMSP142 also resulted in significantly greater antibody responses in mice primed with HAdV5-PyMSP142 using MN compared to the ID route. The highest protection against blood-stage malaria challenge was observed when a heterologous route of immunization (MN/ID) was used. Therefore, microneedle-mediated immunization has potential to both overcome some of the logistic obstacles surrounding needle-and-syringe-based immunization as well as to facilitate the repeated use of the same adenovirus vaccine thereby potentially reducing manufacturing costs of multiple vaccines. This could have important benefits in the clinical ease of use of adenovirus-based immunization strategies. PMID:25142082

  3. Antibody-cytokine fusion proteins for improving efficacy and safety of cancer therapy.

    Science.gov (United States)

    Valedkarimi, Zahra; Nasiri, Hadi; Aghebati-Maleki, Leili; Majidi, Jafar

    2017-11-01

    Cytokines are key players in the regulation of immune responses both in physiological and pathological states. A number of cytokines have been evaluated in clinical trials and shown promising results in the treatment of different malignancies. Despite this, the clinical application of these molecules may be plagued by undesirable side effects The development of recombinant antibody-cytokine fusion proteins, which offer a means for target delivery of cytokines toward the tumor site, has significantly improved the therapeutic index of these immunomodulatory molecules. Selective tumor localization is provided by the monoclonal antibody component of the fusion protein that binds to the molecules present on the surface of tumor cells or accumulated preferentially in the diseased site. In this manner, the cytokine element is specifically located at the tumor site and can stimulate immune cells with appropriate cytokine receptors. Over the recent years, several antibody-cytokine fusion proteins have been developed with the capacity to target a wide variety of cancers whose application, in some cases, has led to complete rejection of the tumor. These findings support the notion that antibody-cytokine fusion proteins represent huge potential for cancer therapy. This review presents an overview of the advances made in the field of targeted cytokine delivery, which is made possible by genetically engineering antibody-cytokine fusion proteins. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  4. TRADITIONAL AND CASCADE PLASMAPHERESIS IN ANTIBODY TITERS’ REDUCTION IN RENAL TRANSPLANT RECIPIENTS

    Directory of Open Access Journals (Sweden)

    A.V. Vatazin

    2014-01-01

    Full Text Available Introduction. One of the current tasks of transplantology is to overcome «graft-host» immune confl ict. Partially this confl ict is caused by the presence of circulating pre-existing antibodies. Highly sensitized patients have a greater risk of rejection and subsequent graft loss. There are several methods to remove the antibodies, one of which is a double fi ltration plasmapheresis (DFPF. This report presents our experience of DFPF in recipients of high immunologic risk.Aim: to compare the effectiveness of traditional and double filtration plasmapheresis in desensitization of patients with high risk of immunological complications.Methods. The study included 30 patients after kidney transplantation. All patients were classifi ed as high-immunologic risk group. In 15 patients of study group we performed DFPF, in 15 patients of comparison group – traditional plasmapheresis. We monitored the immune status: markers of humoral immunity activation – IgG, IgM, IgA before and after the procedures. DFPF procedure was performed on OctoNova (MeSys, Germany with a plasmafi lter and plasma components separator. Protocol biopsies were performed on days 30 and 90.Results. The concentration of antibodies may be effectively reduced with DFPF. Total IgM and IgG antibodies were reduced by 30–55% of the original level. There was a less albumin loss in case of DFPF application. There is 1 patient with antibody-mediated rejection with graft dysfunction in study group. There are no signs of rejection in 30- and 90-day biopsy in study group. But there were three patients with subclinical antibody-mediated rejection in the comparison group.Conclusion. DFPF can safely and effectively reduce the high titers of antibodies that are responsible for humoral rejection of renal allograft. Reduction of antibodies in sensitized patients immediately after transplantation may improve graft function.

  5. Cells of the J774 macrophage cell line are primed for antibody-dependent cell-mediated cytotoxicity following exposure to γ-irradiation

    International Nuclear Information System (INIS)

    Duerst, R.; Werberig, K.

    1991-01-01

    Activation of macrophages (M phi) for host defense against tumor cells follows a sequence of priming events followed by an initiating stimulus that results in production and release of cytotoxic molecules that mediate target cell killing. The authors have developed a model to study specific macrophage cytotoxicity in vitro utilizing a cultured murine M phi cell line, J774. Specific cytotoxicity of cultured human gastrointestinal tumor cells is achieved in the presence of murine IgG2a monoclonal antibody (mAb) 17-1-A. The ability of these cells to mediate antibody-dependent cell-mediated cytotoxicity (ADCC) is greatly enhanced following gamma-irradiation. ADCC can be demonstrated at mAb 17-1-A concentrations greater than or equal to 1 microgram/ml and effector/target cell ratios greater than or equal to 2. Exposure to doses greater than or equal to 10 Gy of gamma-irradiation increases ADCC threefold. Varying the duration from J774 M phi exposure to γ-irradiation until addition of antibody-coated target cells showed that the primed state for ADCC is stable for at least 8 days but approximately 24 hr is required for complete development of the primed state. mAb-dependent target cell death begins 8 hr after addition of mAb and labeled target cells to primed effector cells and is complete by 24 hr. Incubation of unirradiated J774 M phi effector cells with recombinant murine interferon-γ (rmIFN-γ) also results in enhanced ADCC, but the extent of target cell killing achieved is less than that following priming by γ-irradiation. Concomitant priming of γ-irradiated J774 M phi with rmIFN-γ increases the extent of ADCC. Further study of irradiated J774 cells may elucidate the molecular pathways utilized by M phi for achieving and maintaining the primed state for ADCC

  6. Enhanced antibody-dependent cellular phagocytosis by chimeric monoclonal antibodies with tandemly repeated Fc domains.

    Science.gov (United States)

    Nagashima, Hiroaki; Ootsubo, Michiko; Fukazawa, Mizuki; Motoi, Sotaro; Konakahara, Shu; Masuho, Yasuhiko

    2011-04-01

    We previously reported that chimeric monoclonal antibodies (mAbs) with tandemly repeated Fc domains, which were developed by introducing tandem repeats of Fc domains downstream of 2 Fab domains, augmented binding avidities for all Fcγ receptors, resulting in enhanced antibody (Ab)-dependent cellular cytotoxicity. Here we investigated regarding Ab-dependent cellular phagocytosis (ADCP) mediated by these chimeric mAbs, which is considered one of the most important mechanisms that kills tumor cells, using two-color flow cytometric methods. ADCP mediated by T3-Ab, a chimeric mAb with 3 tandemly repeated Fc domains, was 5 times more potent than that by native anti-CD20 M-Ab (M-Ab hereafter). Furthermore, T3-Ab-mediated ADCP was resistant to competitive inhibition by intravenous Ig (IVIG), although M-Ab-mediated ADCP decreased in the presence of IVIG. An Fcγ receptor-blocking study demonstrated that T3-Ab mediated ADCP via both FcγRIA and FcγRIIA, whereas M-Ab mediated ADCP exclusively via FcγRIA. These results suggest that chimeric mAbs with tandemly repeated Fc domains enhance ADCP as well as ADCC, and that Fc multimerization may significantly enhance the efficacy of therapeutic Abs. Copyright © 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  7. Baculovirus-mediated gene transfer in butterfly wings in vivo: an efficient expression system with an anti-gp64 antibody.

    Science.gov (United States)

    Dhungel, Bidur; Ohno, Yoshikazu; Matayoshi, Rie; Otaki, Joji M

    2013-03-25

    Candidate genes for color pattern formation in butterfly wings have been known based on gene expression patterns since the 1990s, but their functions remain elusive due to a lack of a functional assay. Several methods of transferring and expressing a foreign gene in butterfly wings have been reported, but they have suffered from low success rates or low expression levels. Here, we developed a simple, practical method to efficiently deliver and express a foreign gene using baculovirus-mediated gene transfer in butterfly wings in vivo. A recombinant baculovirus containing a gene for green fluorescent protein (GFP) was injected into pupae of the blue pansy butterfly Junonia orithya (Nymphalidae). GFP fluorescence was detected in the pupal wings and other body parts of the injected individuals three to five days post-injection at various degrees of fluorescence. We obtained a high GFP expression rate at relatively high virus titers, but it was associated with pupal death before color pattern formation in wings. To reduce the high mortality rate caused by the baculovirus treatment, we administered an anti-gp64 antibody, which was raised against baculovirus coat protein gp64, to infected pupae after the baculovirus injection. This treatment greatly reduced the mortality rate of the infected pupae. GFP fluorescence was observed in pupal and adult wings and other body parts of the antibody-treated individuals at various degrees of fluorescence. Importantly, we obtained completely developed wings with a normal color pattern, in which fluorescent signals originated directly from scales or the basal membrane after the removal of scales. GFP fluorescence in wing tissues spatially coincided with anti-GFP antibody staining, confirming that the fluorescent signals originated from the expressed GFP molecules. Our baculovirus-mediated gene transfer system with an anti-gp64 antibody is reasonably efficient, and it can be an invaluable tool to transfer, express, and functionally

  8. Improved quantification of a commercial enzyme-linked immunosorbent assay kit for measuring anti-MDA5 antibody.

    Science.gov (United States)

    Gono, Takahisa; Okazaki, Yuka; Murakami, Akihiro; Kuwana, Masataka

    2018-04-09

    To compare the quantitative performance for measuring anti-MDA5 antibody titer of two enzyme-linked immunosorbent assay (ELISA) systems: an in-house ELISA and the commercial MESACUP TM anti-MDA5 test. Anti-MDA5 antibody titer was measured in sera from 70 patients with dermatomyositis using an in-house ELISA and the MESACUP TM anti-MDA5 test side-by-side. For the commercial ELISA kit, serum samples diluted 1:101 were used according to the manufacturer's protocol, but serial dilutions of sera were also examined to identify the optimal serum dilution for quantification. The anti-MDA5 antibody titers measured by the in-house and commercial ELISAs were positively correlated with each other (r = 0.53, p = .0001), but the antibody titer measured by the commercial ELISA was less sensitive to change after medical treatment, and 37 (80%) of 46 anti-MDA5-positive sera had antibody titer exceeding the quantification range specified by the manufacturer (≥150 index). Experiments using diluted serum samples revealed that diluting the sera 1:5050 improved the quantitative performance of the MESACUP TM anti-MDA5 test, including a better correlation with the in-house ELISA results and an increased sensitivity to change. We improved the ability of the commercial ELISA kit to quantify anti-MDA5 antibody titer by altering its protocol.

  9. Incorporation of FcRn-mediated disposition model to describe the population pharmacokinetics of therapeutic monoclonal IgG antibody in clinical patients.

    Science.gov (United States)

    Ng, Chee M

    2016-03-01

    The two-compartment linear model used to describe the population pharmacokinetics (PK) of many therapeutic monoclonal antibodies (TMAbs) offered little biological insight to antibody disposition in humans. The purpose of this study is to develop a semi-mechanistic FcRn-mediated IgG disposition model to describe the population PK of TMAbs in clinical patients. A standard two-compartment linear PK model from a previously published population PK model of pertuzumab was used to simulate intensive PK data of 100 subjects for model development. Two different semi-mechanistic FcRn-mediated IgG disposition models were developed and First Order Conditional Estimation (FOCE) with the interaction method in NONMEM was used to obtain the final model estimates. The performances of these models were then compared with the two-compartment linear PK model used to simulate the data for model development. A semi-mechanistic FcRn-mediated IgG disposition model consisting of a peripheral tissue compartment and FcRn-containing endosomes in the central compartment best describes the simulated pertuzumab population PK data. This developed semi-mechanistic population PK model had the same number of model parameters, produced very similar concentration-time profiles but provided additional biological insight to the FcRn-mediated IgG disposition in human subjects compared with the standard linear two-compartment linear PK model. This first reported semi-mechanistic model may serve as an important model framework for developing future population PK models of TMAbs in clinical patients. Copyright © 2015 John Wiley & Sons, Ltd.

  10. A potential therapy for chordoma via antibody-dependent cell-mediated cytotoxicity employing NK or high-affinity NK cells in combination with cetuximab.

    Science.gov (United States)

    Fujii, Rika; Schlom, Jeffrey; Hodge, James W

    2018-05-01

    OBJECTIVE Chordoma is a rare bone tumor derived from the notochord and is resistant to conventional therapies such as chemotherapy, radiotherapy, and targeting therapeutics. Expression of epidermal growth factor receptor (EGFR) in a large proportion of chordoma specimens indicates a potential target for therapeutic intervention. In this study the authors investigated the potential role of the anti-EGFR antibody cetuximab in immunotherapy for chordoma. METHODS Since cetuximab is a monoclonal antibody of the IgG1 isotype, it has the potential to mediate antibody-dependent cell-mediated cytotoxicity (ADCC) employing natural killer (NK) cells as effectors. Polymorphisms in the CD16 allele expressed on NK cells have been shown to influence the degree of ADCC of tumor cells, with the high-affinity valine (V)/V allele being responsible for more lysis than the V/phenylalanine (F) or FF allele. Unfortunately, however, only approximately 10% of the population expresses the VV allele on NK cells. An NK cell line, NK-92, has now been engineered to endogenously express IL-2 and the high-affinity CD16 allele. These irradiated high-affinity (ha)NK cells were analyzed for lysis of chordoma cells with and without cetuximab, and the levels of lysis observed in ADCC were compared with those of NK cells from donors expressing the VV, VF, and FF alleles. RESULTS Here the authors demonstrate for the first time 1) that cetuximab in combination with NK cells can mediate ADCC of chordoma cells; 2) the influence of the NK CD16 polymorphism in cetuximab-mediated ADCC for chordoma cell lysis; 3) that engineered haNK cells-that is, cells transduced to express the CD16 V158 FcγRIIIa receptor-bind cetuximab with similar affinity to normal NK cells expressing the high-affinity VV allele; and 4) that irradiated haNK cells induce ADCC with cetuximab in chordoma cells. CONCLUSIONS These studies provide rationale for the use of cetuximab in combination with irradiated haNK cells for therapy for

  11. Improved tumor localization with (strept)avidin and labeled biotin as a substitute for antibody

    International Nuclear Information System (INIS)

    Hnatowich, D.J.; Fritz, B.; Virzi, F.; Mardirossian, G.; Rusckowski, M.

    1993-01-01

    We have investigated tumor localization with labeled biotin administered subsequent to unlabeled and unconjugated streptavidin. Nude mice bearing anti-CEA tumors (LS174T) received 10 μg of 111 In-labeled anti-CEA antibody (C110) or 111 In-labeled streptavidin with sacrifice 5 h later. In an examination of pretargeting, other animals received 50 μg of unlabeled streptavidin followed 3 h later with 1 μg of 111 In-labeled biotin (EB 1 ) and sacrifice 2 h later. The biodistribution of labeled streptavidin was similar to that of labeled specific antibody except for lower blood and higher kidney levels. Tumor levels were also lower with labeled streptavidin but, because of still lower levels in liver and blood, the tumor/normal tissue ratios were improved. When unlabeled streptavidin was administered and followed by labeled biotin (pretargeting), tumor levels were further reduced modestly; however, normal tissue levels were greatly reduced such that the tumor/blood and tumor/liver ratios were 10.6 and 2.2 vs 1.5 and 0.5 for the specific antibody. Improvements were seen in all tissues sampled with the exception of kidney and muscle. A further control of labeled biotin alone showed minimal accumulation in all tissues with the exception of kidneys. In conclusion, the accumulation of (strept)avidin by passive diffusion in tumor may be comparable, at early times, to the accumulation of specific antibody. By combining the administration of unlabeled (strept)avidin with labeled biotin, tumor targeting may potentially be improved. (author)

  12. Circulating angiotensin type II receptor: Possible marker for antibody mediated rejection after renal transplantation?

    Science.gov (United States)

    Kimball, Pamela M; Gupta, Gaurav; McDougan, Felecia

    2017-10-01

    Presence of antibody [Ab] against angiotensin receptor [AT1R] indicates heightened risk for antibody mediated rejection [AMR] after transplantation but is insufficient as a marker. We speculated AT1R might be released systemically because of AMR and might be a useful biomarker. AT1R was measured in blood from 73 Normals and 72 renal patients pre- and post-transplantation. Patients were stratified as AMR-free [Gp1], AMR1yr [Gp3]. AT1R was higher [13±26vs.367±537, p<0.01)] and more prevalent [20% vs. 92%, p<0.01] among renal patients than Normals. Pretransplant levels were similar [p=ns] between groups. One-year posttransplant levels approached [p<0.01] normalcy for Gps1+3 but spiked during AMR and remained elevated [155±58, p<0.01] for 50% Gp2 patients. One-year AT1R levels were higher among subsequent graft failures than surviving grafts [171±267vs. 38±50, p<0.01]. Pretransplant AT1R was abnormally elevated: possibly indicating ongoing tissue injury. Pretransplant AT1R didn't predict risk for AMR. However, AT1R spiked during early AMR and sustained elevations were associated with poorer outcomes. Copyright © 2017. Published by Elsevier Inc.

  13. Polyclonal and monoclonal antibodies in clinic.

    Science.gov (United States)

    Wootla, Bharath; Denic, Aleksandar; Rodriguez, Moses

    2014-01-01

    Immunoglobulins (Ig) or antibodies are heavy plasma proteins, with sugar chains added to amino-acid residues by N-linked glycosylation and occasionally by O-linked glycosylation. The versatility of antibodies is demonstrated by the various functions that they mediate such as neutralization, agglutination, fixation with activation of complement and activation of effector cells. Naturally occurring antibodies protect the organism against harmful pathogens, viruses and infections. In addition, almost any organic chemical induces antibody production of antibodies that would bind specifically to the chemical. These antibodies are often produced from multiple B cell clones and referred to as polyclonal antibodies. In recent years, scientists have exploited the highly evolved machinery of the immune system to produce structurally and functionally complex molecules such as antibodies from a single B clone, heralding the era of monoclonal antibodies. Most of the antibodies currently in the clinic, target components of the immune system, are not curative and seek to alleviate symptoms rather than cure disease. Our group used a novel strategy to identify reparative human monoclonal antibodies distinct from conventional antibodies. In this chapter, we discuss the therapeutic relevance of both polyclonal and monoclonal antibodies in clinic.

  14. Antibody Fragments as Potential Biopharmaceuticals for Cancer Therapy: Success and Limitations.

    Science.gov (United States)

    Kholodenko, Roman V; Kalinovsky, Daniel V; Doronin, Igor I; Ponomarev, Eugene D; Kholodenko, Irina V

    2017-08-17

    Monoclonal antibodies (mAbs) are an important class of therapeutic agents approved for the therapy of many types of malignancies. However, in certain cases applications of conventional mAbs have several limitations in anticancer immunotherapy. These limitations include insufficient efficacy and adverse effects. The antigen-binding fragments of antibodies have a considerable potential to overcome the disadvantages of conventional mAbs, such as poor penetration into solid tumors and Fc-mediated bystander activation of the immune system. Fragments of antibodies retain antigen specificity and part of functional properties of conventional mAbs and at the same time have much better penetration into the tumors and a greatly reduced level of adverse effects. Recent advantages in antibody engineering allowed to produce different types of antibody fragments with improved structure and properties for efficient elimination of tumor cells. These molecules opened up new perspectives for anticancer therapy. Here we will overview the structural features of the various types of antibody fragments and their applications for anticancer therapy as separate molecules and as part of complex conjugates or structures. Mechanisms of antitumor action of antibody fragments as well as their advantages and disadvantages for clinical application will be discussed in this review. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  15. Human Cell Line-Derived Monoclonal IgA Antibodies for Cancer Immunotherapy

    Directory of Open Access Journals (Sweden)

    Felix Hart

    2017-05-01

    Full Text Available IgA antibodies have great potential to improve the functional diversity of current IgG antibody-based cancer immunotherapy options. However, IgA production and purification is not well established, which can at least in part be attributed to the more complex glycosylation as compared to IgG antibodies. IgA antibodies possess up to five N-glycosylation sites within their constant region of the heavy chain as compared to one site for IgG antibodies. The human GlycoExpress expression system was developed to produce biotherapeutics with optimized glycosylation and used here to generate a panel of IgA isotype antibodies directed against targets for solid (TA-mucin 1, Her2, EGFR, Thomsen–Friedenreich and hematological (CD20 cancer indications. The feasibility of good manufacturing practice was shown by the production of 11 g IgA within 35 days in a one liter perfusion bioreactor, and IgA antibodies in high purity were obtained after purification. The monoclonal IgA antibodies possessed a high sialylation degree, and no non-human glycan structures were detected. Kinetic analysis revealed increased avidity antigen binding for IgA dimers as compared to monomeric antibodies. The IgA antibodies exhibited potent Fab- and Fc-mediated functionalities against cancer cell lines, whereby especially granulocytes are recruited. Therefore, for patients who do not sufficiently benefit from therapeutic IgG antibodies, IgA antibodies may complement current regiment options and represent a promising strategy for cancer immunotherapy. In conclusion, a panel of novel biofunctional IgA antibodies with human glycosylation was successfully generated.

  16. Fcγ receptor-mediated inflammation inhibits axon regeneration.

    Directory of Open Access Journals (Sweden)

    Gang Zhang

    Full Text Available Anti-glycan/ganglioside antibodies are the most common immune effectors found in patients with Guillain-Barré Syndrome, which is a peripheral autoimmune neuropathy. We previously reported that disease-relevant anti-glycan autoantibodies inhibited axon regeneration, which echo the clinical association of these antibodies and poor recovery in Guillain-Barré Syndrome. However, the specific molecular and cellular elements involved in this antibody-mediated inhibition of axon regeneration are not previously defined. This study examined the role of Fcγ receptors and macrophages in the antibody-mediated inhibition of axon regeneration. A well characterized antibody passive transfer sciatic nerve crush and transplant models were used to study the anti-ganglioside antibody-mediated inhibition of axon regeneration in wild type and various mutant and transgenic mice with altered expression of specific Fcγ receptors and macrophage/microglia populations. Outcome measures included behavior, electrophysiology, morphometry, immunocytochemistry, quantitative real-time PCR, and western blotting. We demonstrate that the presence of autoantibodies, directed against neuronal/axonal cell surface gangliosides, in the injured mammalian peripheral nerves switch the proregenerative inflammatory environment to growth inhibitory milieu by engaging specific activating Fcγ receptors on recruited monocyte-derived macrophages to cause severe inhibition of axon regeneration. Our data demonstrate that the antibody orchestrated Fcγ receptor-mediated switch in inflammation is one mechanism underlying inhibition of axon regeneration. These findings have clinical implications for nerve repair and recovery in antibody-mediated immune neuropathies. Our results add to the complexity of axon regeneration in injured peripheral and central nervous systems as adverse effects of B cells and autoantibodies on neural injury and repair are increasingly recognized.

  17. The Impact of HLA Class I-Specific Killer Cell Immunoglobulin-Like Receptors on Antibody-Dependent Natural Killer Cell-Mediated Cytotoxicity and Organ Allograft Rejection.

    Science.gov (United States)

    Rajalingam, Raja

    2016-01-01

    Natural killer (NK) cells of the innate immune system are cytotoxic lymphocytes that play an important roles following transplantation of solid organs and hematopoietic stem cells. Recognition of self-human leukocyte antigen (HLA) class I molecules by inhibitory killer cell immunoglobulin-like receptors (KIRs) is involved in the calibration of NK cell effector capacities during the developmental stage, allowing the subsequent recognition and elimination of target cells with decreased expression of self-HLA class I (due to virus infection or tumor transformation) or HLA class I disparities (in the setting of allogeneic transplantation). NK cells expressing an inhibitory KIR-binding self-HLA can be activated when confronted with allografts lacking a ligand for the inhibitory receptor. Following the response of the adaptive immune system, NK cells can further destroy allograft endothelium by antibody-dependent cell-mediated cytotoxicity (ADCC), triggered through cross-linking of the CD16 Fc receptor by donor-specific antibodies bound to allograft. Upon recognizing allogeneic target cells, NK cells also secrete cytokines and chemokines that drive maturation of dendritic cells to promote cellular and humoral adaptive immune responses against the allograft. The cumulative activating and inhibitory signals generated by ligation of the receptors regulates mature NK cell killing of target cells and their production of cytokines and chemokines. This review summarizes the role of NK cells in allograft rejection and proposes mechanistic concepts that indicate a prominent role for KIR-HLA interactions in facilitating NK cells for Fc receptor-mediated ADCC effector function involved in antibody-mediated rejection of solid organ transplants.

  18. The impact of HLA class I-specific killer cell immunoglobulin-like receptors on antibody-dependent natural killer cell-mediated cytotoxicity and organ allograft rejection

    Directory of Open Access Journals (Sweden)

    Raja Rajalingam

    2016-12-01

    Full Text Available Natural killer (NK cells of the innate immune system are cytotoxic lymphocytes that play important roles following transplantation of solid organs and hematopoietic stem cells. Recognition of self HLA class I molecules by inhibitory killer cell immunoglobulin-like receptors (KIR is involved in the calibration of NK cell effector capacities during a developmental stage, allowing the subsequent recognition and elimination of target cells with decreased expression of self HLA class I (due to virus infection or tumor transformation or HLA class I disparities (in the setting of allogeneic transplantation. NK cells expressing an inhibitory KIR binding self HLA can be activated when confronted with allografts lacking a ligand for the inhibitory receptor. Following the response of the adaptive immune system, NK cells can further destroy allograft endothelium by antibody-dependent cell-mediated cytotoxicity (ADCC, triggered through cross-linking of the CD16 Fc receptor by donor-specific antibodies bound to allograft. Upon recognizing allogeneic target cells, NK cells also secrete cytokines and chemokines that drive maturation of dendritic cells to promote cellular and humoral adaptive immune responses against the allograft. The cumulative activating and inhibitory signals generated by ligation of the receptors regulates mature NK cell killing of target cells and their production of cytokines and chemokines. This review summarizes the role of NK cells in allograft rejection and proposes mechanistic concepts that indicate a prominent role for KIR-HLA interactions in facilitating NK cells for Fc receptor-mediated ADCC effector function involved in antibody-mediated rejection of solid organ transplants.

  19. Improved Tumor Penetration and Single-Cell Targeting of Antibody-Drug Conjugates Increases Anticancer Efficacy and Host Survival.

    Science.gov (United States)

    Cilliers, Cornelius; Menezes, Bruna; Nessler, Ian; Linderman, Jennifer; Thurber, Greg M

    2018-02-01

    Current antibody-drug conjugates (ADC) have made advances in engineering the antibody, linker, conjugation site, small-molecule payload, and drug-to-antibody ratio (DAR). However, the relationship between heterogeneous intratumoral distribution and efficacy of ADCs is poorly understood. Here, we compared trastuzumab and ado-trastuzumab emtansine (T-DM1) to study the impact of ADC tumor distribution on efficacy. In a mouse xenograft model insensitive to trastuzumab, coadministration of trastuzumab with a fixed dose of T-DM1 at 3:1 and 8:1 ratios dramatically improved ADC tumor penetration and resulted in twice the improvement in median survival compared with T-DM1 alone. In this setting, the effective DAR was lowered, decreasing the amount of payload delivered to each targeted cell but increasing the number of cells that received payload. This result is counterintuitive because trastuzumab acts as an antagonist in vitro and has no single-agent efficacy in vivo , yet improves the effectiveness of T-DM1 in vivo Novel dual-channel fluorescence ratios quantified single-cell ADC uptake and metabolism and confirmed that the in vivo cellular dose of T-DM1 alone exceeded the minimum required for efficacy in this model. In addition, this technique characterized cellular pharmacokinetics with heterogeneous delivery after 1 day, degradation and payload release by 2 days, and in vitro cell killing and in vivo tumor shrinkage 2 to 3 days later. This work demonstrates that the intratumoral distribution of ADC, independent of payload dose or plasma clearance, plays a major role in ADC efficacy. Significance: This study shows how lowering the drug-to-antibody ratio during treatment can improve the intratumoral distribution of a antibody-drug conjugate, with implications for improving the efficacy of this class of cancer drugs. Cancer Res; 78(3); 758-68. ©2017 AACR . ©2017 American Association for Cancer Research.

  20. Addressing safety liabilities of TfR bispecific antibodies that cross the blood-brain barrier.

    Science.gov (United States)

    Couch, Jessica A; Yu, Y Joy; Zhang, Yin; Tarrant, Jacqueline M; Fuji, Reina N; Meilandt, William J; Solanoy, Hilda; Tong, Raymond K; Hoyte, Kwame; Luk, Wilman; Lu, Yanmei; Gadkar, Kapil; Prabhu, Saileta; Ordonia, Benjamin A; Nguyen, Quyen; Lin, Yuwen; Lin, Zhonghua; Balazs, Mercedesz; Scearce-Levie, Kimberly; Ernst, James A; Dennis, Mark S; Watts, Ryan J

    2013-05-01

    Bispecific antibodies using the transferrin receptor (TfR) have shown promise for boosting antibody uptake in brain. Nevertheless, there are limited data on the therapeutic properties including safety liabilities that will enable successful development of TfR-based therapeutics. We evaluate TfR/BACE1 bispecific antibody variants in mouse and show that reducing TfR binding affinity improves not only brain uptake but also peripheral exposure and the safety profile of these antibodies. We identify and seek to address liabilities of targeting TfR with antibodies, namely, acute clinical signs and decreased circulating reticulocytes observed after dosing. By eliminating Fc effector function, we ameliorated the acute clinical signs and partially rescued a reduction in reticulocytes. Furthermore, we show that complement mediates a residual decrease in reticulocytes observed after Fc effector function is eliminated. These data raise important safety concerns and potential mitigation strategies for the development of TfR-based therapies that are designed to cross the blood-brain barrier.

  1. Antibody-dependent cellular cytotoxicity (ADCC) activity of a novel anti-PD-L1 antibody avelumab (MSB0010718C) on human tumor cells

    OpenAIRE

    Boyerinas, Benjamin; Jochems, Caroline; Fantini, Massimo; Heery, Christopher R.; Gulley, James L.; Tsang, Kwong Yok; Schlom, Jeffrey

    2015-01-01

    Several anti-PD1/PD-L1 monoclonal antibodies (MAb) are currently providing evidence of clinical benefit in subsets of cancer patients. The mode of action of these MAbs is to inhibit PD1 on immune cells interacting with PD-L1 on tumor cells. These MAbs are either designed or engineered to eliminate antibody-dependent cell-mediated cytotoxicity (ADCC), which, however, has been implicated as an important mechanism in several highly effective MAb-mediated cancer therapies. A fully human anti-PD-L...

  2. Affinity improvement of a therapeutic antibody by structure-based computational design: generation of electrostatic interactions in the transition state stabilizes the antibody-antigen complex.

    Directory of Open Access Journals (Sweden)

    Masato Kiyoshi

    Full Text Available The optimization of antibodies is a desirable goal towards the development of better therapeutic strategies. The antibody 11K2 was previously developed as a therapeutic tool for inflammatory diseases, and displays very high affinity (4.6 pM for its antigen the chemokine MCP-1 (monocyte chemo-attractant protein-1. We have employed a virtual library of mutations of 11K2 to identify antibody variants of potentially higher affinity, and to establish benchmarks in the engineering of a mature therapeutic antibody. The most promising candidates identified in the virtual screening were examined by surface plasmon resonance to validate the computational predictions, and to characterize their binding affinity and key thermodynamic properties in detail. Only mutations in the light-chain of the antibody are effective at enhancing its affinity for the antigen in vitro, suggesting that the interaction surface of the heavy-chain (dominated by the hot-spot residue Phe101 is not amenable to optimization. The single-mutation with the highest affinity is L-N31R (4.6-fold higher affinity than wild-type antibody. Importantly, all the single-mutations showing increase affinity incorporate a charged residue (Arg, Asp, or Glu. The characterization of the relevant thermodynamic parameters clarifies the energetic mechanism. Essentially, the formation of new electrostatic interactions early in the binding reaction coordinate (transition state or earlier benefits the durability of the antibody-antigen complex. The combination of in silico calculations and thermodynamic analysis is an effective strategy to improve the affinity of a matured therapeutic antibody.

  3. Molecular determinants of dengue virus 2 envelope protein important for virus entry in FcγRIIA-mediated antibody-dependent enhancement of infection

    International Nuclear Information System (INIS)

    Chotiwan, Nunya; Roehrig, John T.; Schlesinger, Jacob J.; Blair, Carol D.; Huang, Claire Y.-H.

    2014-01-01

    Antibody-dependent enhancement (ADE) of infection may cause severe illness in patients suffering a secondary infection by a heterologous dengue virus (DENV) serotype. During ADE of infection, cross-reactive non- or poorly-neutralizing antibodies form infectious virus-Ab complexes with the newly infecting serotype and enhance virus infection by binding to the Fcγ receptors (FcγR) on FcγR-bearing cells. In this study, we determined that molecular determinants of DENV2 envelope protein critical for virus entry during non-ADE infection are also required for ADE infection mediated by FcγRIIA, and binding of virus-Ab complexes with FcγRIIA alone is not sufficient for ADE of infection. The FcγRIIA mainly plays an auxiliary role in concentrating the virus–Ab complex to the cell surface, and other primary cellular receptors are required for virus entry. Understanding the viral entry pathway in ADE of DENV infection will greatly facilitate rational designs of anti-viral therapeutics against severe dengue disease associated with ADE. - Highlights: • KKK305/307/310 in DENV2 E-DIII is critical for virus attachment in ADE and non-ADE infection. • Binding of DENV2–Ab complex with FcγRII alone is not sufficient for virus entry in ADE infection. • Other primary receptors were required for DENV2 internalization during FcγRII–mediated ADE. • G104 and L135 of DENV2 E are critical for virus-mediated membrane fusion. • DENV2 virus-mediated membrane fusion is required for both ADE and non-ADE infection

  4. Molecular determinants of dengue virus 2 envelope protein important for virus entry in FcγRIIA-mediated antibody-dependent enhancement of infection

    Energy Technology Data Exchange (ETDEWEB)

    Chotiwan, Nunya; Roehrig, John T. [Arboviral Diseases Branch, Division of Vector-Borne Disease, Centers for Disease Control and Prevention, Fort Collins, CO 80521 (United States); Schlesinger, Jacob J. [Department of Medicine, University of Rochester, Rochester, NY 14642 (United States); Blair, Carol D. [Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523 (United States); Huang, Claire Y.-H., E-mail: yxh0@cdc.gov [Arboviral Diseases Branch, Division of Vector-Borne Disease, Centers for Disease Control and Prevention, Fort Collins, CO 80521 (United States)

    2014-05-15

    Antibody-dependent enhancement (ADE) of infection may cause severe illness in patients suffering a secondary infection by a heterologous dengue virus (DENV) serotype. During ADE of infection, cross-reactive non- or poorly-neutralizing antibodies form infectious virus-Ab complexes with the newly infecting serotype and enhance virus infection by binding to the Fcγ receptors (FcγR) on FcγR-bearing cells. In this study, we determined that molecular determinants of DENV2 envelope protein critical for virus entry during non-ADE infection are also required for ADE infection mediated by FcγRIIA, and binding of virus-Ab complexes with FcγRIIA alone is not sufficient for ADE of infection. The FcγRIIA mainly plays an auxiliary role in concentrating the virus–Ab complex to the cell surface, and other primary cellular receptors are required for virus entry. Understanding the viral entry pathway in ADE of DENV infection will greatly facilitate rational designs of anti-viral therapeutics against severe dengue disease associated with ADE. - Highlights: • KKK305/307/310 in DENV2 E-DIII is critical for virus attachment in ADE and non-ADE infection. • Binding of DENV2–Ab complex with FcγRII alone is not sufficient for virus entry in ADE infection. • Other primary receptors were required for DENV2 internalization during FcγRII–mediated ADE. • G104 and L135 of DENV2 E are critical for virus-mediated membrane fusion. • DENV2 virus-mediated membrane fusion is required for both ADE and non-ADE infection.

  5. Chlamydia trachomatis and chlamydial heat shock protein 60-specific antibody and cell-mediated responses predict tubal factor infertility

    DEFF Research Database (Denmark)

    Tiitinen, A.; Surcel, H.-M.; Halttunen, M.

    2006-01-01

    60)-specific immunoglobulin G (IgG) antibodies were analysed using enzyme-linked immunosorbent assay (ELISA) kits. Proliferative reactivity of peripheral blood mononuclear cells was studied in vitro against Chlamydia elementary body (EB) and recombinant CHSP60 antigens. RESULTS: C. trachomatis......BACKGROUND: To evaluate the role of Chlamydia trachomatis-induced humoral and cell-mediated immune (CMI) responses in predicting tubal factor infertility (TFI). METHODS: Blood samples were taken from 88 women with TFI and 163 control women. C. trachomatis and chlamydial heat shock protein 60 (CHSP...

  6. Re-engineering therapeutic antibodies for Alzheimer's disease as blood-brain barrier penetrating bi-specific antibodies.

    Science.gov (United States)

    Pardridge, William M

    2016-12-01

    Therapeutic antibodies are large molecule drugs that do not cross the blood-brain barrier (BBB). Therefore, drug development of therapeutic antibodies for Alzheimer's disease (AD) requires that these molecules be re-engineered to enable BBB delivery. This is possible by joining the therapeutic antibody with a transporter antibody, resulting in the engineering of a BBB-penetrating bispecific antibody (BSA). Areas covered: The manuscript covers transporter antibodies that cross the BBB via receptor-mediated transport systems on the BBB, such as the insulin receptor or transferrin receptor. Furthermore, it highlights therapeutic antibodies for AD that target the Abeta amyloid peptide, beta secretase-1, or the metabotropic glutamate receptor-1. BSAs are comprised of both the transporter antibody and the therapeutic antibody, as well as IgG constant region, which can induce immune tolerance or trigger transport via Fc receptors. Expert opinion: Multiple types of BSA molecular designs have been used to engineer BBB-penetrating BSAs, which differ in valency and spatial orientation of the transporter and therapeutic domains of the BSA. The plasma pharmacokinetics and dosing regimens of BSAs differ from that of conventional therapeutic antibodies. BBB-penetrating BSAs may be engineered in the future as new treatments of AD, as well as other neural disorders.

  7. Immunogenicity of anti-tumor necrosis factor antibodies - toward improved methods of anti-antibody measurement

    NARCIS (Netherlands)

    Aarden, Lucien; Ruuls, Sigrid R.; Wolbink, Gertjan

    2008-01-01

    To date, millions of people have been treated with therapeutic monoclonal antibodies (TmAbs) for various indications. It is becoming increasingly clear that TmAbs can be immunogenic, which may reduce efficacy or induce adverse effects. Over the years, the importance of antibody formation has been

  8. Identification of antibody glycosylation structures that predict monoclonal antibody Fc-effector function.

    Science.gov (United States)

    Chung, Amy W; Crispin, Max; Pritchard, Laura; Robinson, Hannah; Gorny, Miroslaw K; Yu, Xiaojie; Bailey-Kellogg, Chris; Ackerman, Margaret E; Scanlan, Chris; Zolla-Pazner, Susan; Alter, Galit

    2014-11-13

    To determine monoclonal antibody (mAb) features that predict fragment crystalizable (Fc)-mediated effector functions against HIV. Monoclonal antibodies, derived from Chinese hamster ovary cells or Epstein-Barr virus-immortalized mouse heteromyelomas, with specificity to key regions of the HIV envelope including gp120-V2, gp120-V3 loop, gp120-CD4(+) binding site, and gp41-specific antibodies, were functionally profiled to determine the relative contribution of the variable and constant domain features of the antibodies in driving robust Fc-effector functions. Each mAb was assayed for antibody-binding affinity to gp140(SR162), antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP) and for the ability to bind to FcγRIIa, FcγRIIb and FcγRIIIa receptors. Antibody glycan profiles were determined by HPLC. Neither the specificity nor the affinity of the mAbs determined the potency of Fc-effector function. FcγRIIIa binding strongly predicted ADCC and decreased galactose content inversely correlated with ADCP, whereas N-glycolylneuraminic acid-containing structures exhibited enhanced ADCP. Additionally, the bi-antenary glycan arm onto which galactose was added predicted enhanced binding to FcγRIIIa and ADCC activity, independent of the specificity of the mAb. Our studies point to the specific Fc-glycan structures that can selectively promote Fc-effector functions independently of the antibody specificity. Furthermore, we demonstrated antibody glycan structures associated with enhanced ADCP activity, an emerging Fc-effector function that may aid in the control and clearance of HIV infection.

  9. Relation between IgG antibodies to foods and IgE antibodies to milk, egg, cat, dog and/or mite in a cross-sectional study

    NARCIS (Netherlands)

    Eysink, P. E.; de Jong, M. H.; Bindels, P. J.; Scharp-van der Linden, V. T.; de Groot, C. J.; Stapel, S. O.; Aalberse, R. C.

    1999-01-01

    Because IgG antibodies to foods can be detected before IgE antibodies to inhalants, increased levels of IgG antibodies to foods might be used as a predictor of IgE-mediated allergy in initially nonatopic children. To examine the cross-sectional relation between IgG to foods (i.e. mixture of wheat

  10. Delivery of Flightless I Neutralizing Antibody from Porous Silicon Nanoparticles Improves Wound Healing in Diabetic Mice.

    Science.gov (United States)

    Turner, Christopher T; McInnes, Steven J P; Melville, Elizabeth; Cowin, Allison J; Voelcker, Nicolas H

    2017-01-01

    Flightless I (Flii) is elevated in human chronic wounds and is a negative regulator of wound repair. Decreasing its activity improves healing responses. Flii neutralizing antibodies (FnAbs) decrease Flii activity in vivo and hold significant promise as healing agents. However, to avoid the need for repeated application in a clinical setting and to protect the therapeutic antibody from the hostile environment of the wound, suitable delivery vehicles are required. In this study, the use of porous silicon nanoparticles (pSi NPs) is demonstrated for the controlled release of FnAb to diabetic wounds. We achieve FnAb loading regimens exceeding 250 µg antibody per mg of vehicle. FnAb-loaded pSi NPs increase keratinocyte proliferation and enhance migration in scratch wound assays. Release studies confirm the functionality of the FnAb in terms of Flii binding. Using a streptozotocin-induced model of diabetic wound healing, a significant improvement in healing is observed for mice treated with FnAb-loaded pSi NPs compared to controls, including FnAb alone. FnAb-loaded pSi NPs treated with proteases show intact and functional antibody for up to 7 d post-treatment, suggesting protection of the antibodies from proteolytic degradation in wound fluid. pSi NPs may therefore enable new therapeutic approaches for the treatment of diabetic ulcers. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Dual antibody therapy to harness the innate anti-tumor immune response to enhance antibody targeting of tumors.

    Science.gov (United States)

    Chester, Cariad; Marabelle, Aurelien; Houot, Roch; Kohrt, Holbrook E

    2015-04-01

    Cancer immunotherapy is a rapidly evolving field that offers a novel paradigm for cancer treatment: therapies focus on enhancing the immune system's innate and adaptive anti-tumor response. Early immunotherapeutics have achieved impressive clinical outcomes and monoclonal antibodies are now integral to therapeutic strategies in a variety of cancers. However, only recently have antibodies targeting innate immune cells entered clinical development. Innate immune effector cells play important roles in generating and maintaining antitumor immunity. Antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) are important innate immune mechanisms for tumor eradication. These cytolytic processes are initiated by the detection of a tumor-targeting antibody and can be augmented by activating co-stimulatory pathways or blocking inhibitory signals on innate immune cells. The combination of FDA-approved monoclonal antibodies with innate effector-targeting antibodies has demonstrated potent preclinical therapeutic synergy and early-phase combinatorial clinical trials are ongoing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Antitumor activity of anti-C-ERC/mesothelin monoclonal antibody in vivo.

    Science.gov (United States)

    Inami, Koichi; Abe, Masaaki; Takeda, Kazuyoshi; Hagiwara, Yoshiaki; Maeda, Masahiro; Segawa, Tatsuya; Suyama, Masafumi; Watanabe, Sumio; Hino, Okio

    2010-04-01

    Mesothelioma is an aggressive cancer often caused by chronic asbestos exposure, and its prognosis is very poor despite the therapies currently used. Due to the long latency period between asbestos exposure and tumor development, the worldwide incidence will increase substantially in the next decades. Thus, novel effective therapies are warranted to improve the prognosis. The ERC/mesothelin gene (MSLN) is expressed in wide variety of human cancers, including mesotheliomas, and encodes a precursor protein cleaved by proteases to generate C-ERC/mesothelin and N-ERC/mesothelin. In this study, we investigated the antitumor activity of C-ERC/mesothelin-specific mouse monoclonal antibody, 22A31, against tumors derived from a human mesothelioma cell line, ACC-MESO-4, in a xenograft experimental model using female BALB/c athymic nude mice. Treatment with 22A31 did not inhibit cell proliferation of ACC-MESO-4 in vitro; however, therapeutic treatment with 22A31 drastically inhibited tumor growth in vivo. 22A31 induced antibody-dependent cell-mediated cytotoxicity by natural killer (NK) cells, but not macrophages, in vitro. Consistently, the F(ab')(2) fragment of 22A31 did not inhibit tumor growth in vivo, nor did it induce antibody-dependent cell mediated cytotoxicity (ADCC) in vitro. Moreover, NK cell depletion diminished the antitumor effect of 22A31. Thus, 22A31 induced NK cell-mediated ADCC and exerted antitumor activity in vivo. 22A31 could have potential as a therapeutic tool to treat C-ERC/mesothelin-expressing cancers including mesothelioma.

  13. Ex-vivo expanded human NK cells express activating receptors that mediate cytotoxicity of allogeneic and autologous cancer cell lines by direct recognition and antibody directed cellular cytotoxicity

    Directory of Open Access Journals (Sweden)

    Campana Dario

    2010-10-01

    Full Text Available Abstract Background The possibility that autologous NK cells could serve as an effective treatment modality for solid tumors has long been considered. However, implementation is hampered by (i the small number of NK cells in peripheral blood, (ii the difficulties associated with large-scale production of GMP compliant cytolytic NK cells, (iii the need to activate the NK cells in order to induce NK cell mediated killing and (iv the constraints imposed by autologous inhibitory receptor-ligand interactions. To address these issues, we determined (i if large numbers of NK cells could be expanded from PBMC and GMP compliant cell fractions derived by elutriation, (ii their ability to kill allogeneic and autologous tumor targets by direct cytotoxitiy and by antibody-mediated cellular cytotoxicity and (iii defined NK cell specific receptor-ligand interactions that mediate tumor target cell killing. Methods Human NK cells were expanded during 14 days. Expansion efficiency, NK receptor repertoire before and after expansion, expression of NK specific ligands, cytolytic activity against allogeneic and autologous tumor targets, with and without the addition of chimeric EGFR monoclonal antibody, were investigated. Results Cell expansion shifted the NK cell receptor repertoire towards activation and resulted in cytotoxicity against various allogeneic tumor cell lines and autologous gastric cancer cells, while sparing normal PBMC. Blocking studies confirmed that autologous cytotoxicity is established through multiple activating receptor-ligand interactions. Importantly, expanded NK cells also mediated ADCC in an autologous and allogeneic setting by antibodies that are currently being used to treat patients with select solid tumors. Conclusion These data demonstrate that large numbers of cytolytic NK cells can be generated from PBMC and lymphocyte-enriched fractions obtained by GMP compliant counter current elutriation from PBMC, establishing the preclinical

  14. Anti-influenza Hyperimmune Immunoglobulin Enhances Fc-functional Antibody Immunity during Human Influenza Infection.

    Science.gov (United States)

    Vanderven, Hillary A; Wragg, Kathleen; Ana-Sosa-Batiz, Fernanda; Kristensen, Anne B; Jegaskanda, Sinthujan; Wheatley, Adam K; Wentworth, Deborah; Wines, Bruce D; Hogarth, P Mark; Rockman, Steve; Kent, Stephen J

    2018-05-31

    New treatments for severe influenza are needed. Passive transfer of influenza-specific hyperimmune pooled immunoglobulin (Flu-IVIG) boosts neutralising antibody responses to past strains in influenza-infected subjects. The effect of Flu-IVIG on antibodies with Fc-mediated functions, which may target diverse influenza strains, is unclear. We studied the capacity of Flu-IVIG, relative to standard IVIG, to bind to Fc receptors and mediate antibody-dependent cellular cytotoxicity in vitro. The effect of Flu-IVIG infusion, compared to placebo infusion, was examined in serial plasma samples from 24 subjects with confirmed influenza infection in the INSIGHT FLU005 pilot study. Flu-IVIG contains higher concentrations of Fc-functional antibodies than IVIG against a diverse range of influenza hemagglutinins. Following infusion of Flu-IVIG into influenza-infected subjects, a transient increase in Fc-functional antibodies was present for 1-3 days against infecting and non-infecting strains of influenza. Flu-IVIG contains antibodies with Fc-mediated functions against influenza virus and passive transfer of Flu-IVIG increases anti-influenza Fc-functional antibodies in the plasma of influenza-infected subjects. Enhancement of Fc-functional antibodies to a diverse range of influenza strains suggests that Flu-IVIG infusion could prove useful in the context of novel influenza virus infections, when there may be minimal or no neutralising antibodies in the Flu-IVIG preparation.

  15. Antibody-Mediated Osseous Regeneration for Bone Tissue Engineering in Canine Segmental Defects

    Directory of Open Access Journals (Sweden)

    A. Khojasteh

    2018-01-01

    Full Text Available Among many applications of therapeutic monoclonal antibodies (mAbs, a unique approach for regenerative medicine has entailed antibody-mediated osseous regeneration (AMOR. In an effort to identify a clinically relevant model of craniofacial defect, the present study investigated the efficacy of mAb specific for bone morphogenetic protein- (BMP- 2 to repair canine segmental mandibular continuity defect model. Accordingly, a 15 mm unilateral segmental defect was created in mandible and fixated with a titanium plate. Anorganic bovine bone mineral with 10% collagen (ABBM-C was functionalized with 25 μg/mL of either chimeric anti-BMP-2 mAb or isotype-matched mAb (negative control. Recombinant human (rh BMP-2 served as positive control. Morphometric analyses were performed on computed tomography (CT and histologic images. Bone densities within healed defect sites at 12 weeks after surgery were 1360.81 ± 10.52 Hounsfield Unit (HU, 1044.27 ± 141.16 HU, and 839.45 ± 179.41 HU, in sites with implanted anti-BMP-2 mAb, rhBMP-2, and isotype mAb groups, respectively. Osteoid bone formation in anti-BMP-2 mAb (42.99% ± 8.67 and rhBMP-2 (48.97% ± 2.96 groups was not significantly different but was higher (p<0.05 than in sites with isotype control mAb (26.8% ± 5.35. In view of the long-term objective of translational application of AMOR in humans, the results of the present study demonstrated the feasibility of AMOR in a large clinically relevant animal model.

  16. Intravenous avidin chase improved localization of radiolabeled streptavidin in intraperitoneal xenograft pretargeted with biotinylated antibody

    International Nuclear Information System (INIS)

    Zhang Meili; Sakahara, Harumi; Yao Zhengsheng; Saga, Tsuneo; Nakamoto, Yuhi; Sato, Noriko; Nakada, Hiroshi; Yamashina, Ikuo; Konishi, Junji

    1997-01-01

    In the present study, we examined the effect of avidin administered intravenously (i.v.) on the biodistribution of radiolabeled streptavidin in mice bearing intraperitoneal (IP) xenografts pretargeted with biotinylated antibody. Tumors were established in nude mice by IP inoculation of LS180 human colon cancer cells. Monoclonal antibody MLS128, which recognizes Tn antigen on mucin, was biotinylated and injected IP into the IP tumor-bearing mice. Radioiodinated streptavidin was administered IP or i.v. 48 h after pretargeting of biotinylated antibody. Avidin was administered i.v. 30 min prior to streptavidin injection. The localization of radioiodinated streptavidin in the tumor pretargeted with biotinylated antibody was significantly higher than that without pretargeting and that of radioiodinated MLS128 by the one-step method. Avidin administration significantly accelerated the clearance of radioiodinated streptavidin in blood and other normal tissues and increased the tumor-to-blood radioactivity ratio regardless of administration route of streptavidin. The i.v. avidin chase improved tumor localization of radiolabeled streptavidin in the IP xenografts pretargeted with biotinylated antibody

  17. Improved tumor localization with (strept)avidin and labeled biotin as a substitute for antibody

    International Nuclear Information System (INIS)

    Hnatowich, D.J.; Fritz, B.; Virzi, F.; Mardirossian, G.; Rusckowski, M.

    1993-01-01

    We have investigated tumor localization with labeled biotin administered subsequent to unlabeled and unconjugated streptavidin. Nude mice bearing anti-CEA tumors (LS174T) received 10 μg of 111 In-labeled anti-CEA antibody (C110) or 111 In-labeled streptavidin with sacrifice 5 h later. In an examination of pretargeting, other animals received 50 μg of unlabeled streptavidin followed 3 h later with 1 μg of 111 In-labeled biotin (EB 1 ) and sacrifice 2 h later. The biodistribution of labeled streptavidin was similar to that of labeled specific antibody except for lower blood and higher kidney levels. Tumor levels were also lower with labeled streptavidin but, because of still lower levels in liver and blood, the tumor/normal tissue ratios were improved. When unlabeled streptavidin was administered and followed by labeled biotin (pretargeting), tumor levels were further reduced modestly; however, normal tissue levels were greatly reduced such that the tumor/blood and tumor/liver ratios were 10.6 and 2.2 vs 1.5 and 0.5 for the specific antibody. Improvements were seen in all tissues sampled with the exception of kidney and muscle. A further control of labeled biotin alone (without the preinjection of streptavidin) showed minimal accumulations in all tissues with the exception of kidneys. In conclusion, the accumulation of (strept)avidin by passive diffusion in tumor may be comparable, at early times, to the accumulation of specific antibody. (author)

  18. Extracorporeal adsorption therapy: A Method to improve targeted radiation delivered by radiometal-labeled monoclonal antibodies

    International Nuclear Information System (INIS)

    Nemecek, Eneida R.; Green, Damian J.; Fisher, Darrell R.; Pagal, John M.; Lin, Yukang; Gopal, A. K.; Durack, Lawrence D.; Rajendran, Joseph G.; Wilbur, D. S.; Nilsson, Rune; Sandberg, Bengt; Press, Oliver W.

    2008-01-01

    Many investigators have demonstrated the ability to treat hematologic malignancies with radiolabeled monoclonal antibodies targeting hematopoietic antigens such as anti-CD20 and anti-CD45. [1-5] Although the remission rates achieved with radioimmunotherapy (RIT) are relatively high, many patients subsequently relapse presumably due to suboptimal delivery of enough radiation to eradicate the malignancy. The dose-response of leukemia and lymphoma to radiation has been proven. Substantial amounts of radiation can be delivered by RIT if followed by hematopoietic cell transplantation to rescue the bone marrow from myeloablation.[ref] However, the maximum dose of RIT that can be used is still limited by toxicity to normal tissues affected by nonspecific delivery of radiation. Efforts to improve RIT focus on improving the therapeutic ratios of radiation in target versus non-target tissues by removing the fraction of radioisotope that fails to bind to target tissues and circulates freely in the bloodstream perfusing non-target tissues. Our group and others have explored several alternatives for removal of unbound circulating antibody. [refs] One such method, extracorporeal adsorption therapy (ECAT) consists of removing unbound antibody by a method similar to plasmapheresis after critical circulation time and distribution of antibody into target tissues have been achieved. Preclinical studies of ECAT in murine xenograft models demonstrated significant improvement in therapeutic ratios of radioactivity. Chen and colleagues demonstrated that a 2-hour ECAT procedure could remove 40 to 70% of the radioactivity from liver, lung and spleen. [ref] Although isotope concentration in the tumor was initially unaffected, a 50% decrease was noted approximately 36 hours after the procedure. This approach was also evaluated in a limited phase I pilot study of patients with refractory B-cell lymphoma. [ref] After radiographic confirmation of tumor localization of a test dose of anti-CD20

  19. Combined use of anti-ErbB monoclonal antibodies and erlotinib enhances antibody-dependent cellular cytotoxicity of wild-type erlotinib-sensitive NSCLC cell lines

    Directory of Open Access Journals (Sweden)

    Cavazzoni Andrea

    2012-12-01

    Full Text Available Abstract Background The epidermal growth factor receptor (EGFR is an established target for anti-cancer treatment in different tumour types. Two different strategies have been explored to inhibit this pivotal molecule in epithelial cancer development: small molecules TKIs and monoclonal antibodies. ErbB/HER-targeting by monoclonal antibodies such as cetuximab and trastuzumab or tyrosine-kinase inhibitors as gefitinib or erlotinib has been proven effective in the treatment of advanced NSCLC. Results In this study we explored the potential of combining either erlotinib with cetuximab or trastuzumab to improve the efficacy of EGFR targeted therapy in EGFR wild-type NSCLC cell lines. Erlotinib treatment was observed to increase EGFR and/or HER2 expression at the plasma membrane level only in NSCLC cell lines sensitive to the drug inducing protein stabilization. The combined treatment had marginal effect on cell proliferation but markedly increased antibody-dependent, NK mediated, cytotoxicity in vitro. Moreover, in the Calu-3 xenograft model, the combination significantly inhibited tumour growth when compared with erlotinib and cetuximab alone. Conclusion Our results indicate that erlotinib increases surface expression of EGFR and/or HER2 only in EGFR-TKI sensitive NSCLC cell lines and, in turns, leads to increased susceptibility to ADCC both in vitro and in a xenograft models. The combination of erlotinib with monoclonal antibodies represents a potential strategy to improve the treatment of wild-type EGFR NSCLC patients sensitive to erlotinib.

  20. Decreased Fc receptor expression on innate immune cells is associated with impaired antibody-mediated cellular phagocytic activity in chronically HIV-1 infected individuals.

    Science.gov (United States)

    Dugast, Anne-Sophie; Tonelli, Andrew; Berger, Christoph T; Ackerman, Margaret E; Sciaranghella, Gaia; Liu, Qingquan; Sips, Magdalena; Toth, Ildiko; Piechocka-Trocha, Alicja; Ghebremichael, Musie; Alter, Galit

    2011-07-05

    In addition to neutralization, antibodies mediate other antiviral activities including antibody-dependent cellular phagocytosis (ADCP), antibody-dependent cellular cytotoxicity (ADCC), as well as complement deposition. While it is established that progressive HIV infection is associated with reduced ADCC and ADCP, the underlying mechanism for this loss of function is unknown. Here we report considerable changes in FcR expression over the course of HIV infection on both mDCs and monocytes, including elevated FcγRI expression in acute HIV infection and reduced expression of FcγRII and FcγRIIIa in chronic HIV infection. Furthermore, selective blockade of FcγRII alone was associated with a loss in ADCP activity, suggesting that FcγRII plays a central role in modulating ADCP. Overall, HIV infection is associated with a number of changes in FcR expression on phagocytic cells that are associated with changes in their ability to respond to antibody-opsonized targets, potentially contributing to a failure in viral clearance in progressive HIV-1 infection. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Decreased Fc-Receptor expression on innate immune cells is associated with impaired antibody mediated cellular phagocytic activity in chronically HIV-1 infected individuals

    Science.gov (United States)

    Dugast, Anne-Sophie; Tonelli, Andrew; Berger, Christoph T.; Ackerman, Margaret E.; Sciaranghella, Gaia; Liu, Qingquan; Sips, Magdalena; Toth, Ildiko; Piechocka-Trocha, Alicja; Ghebremichael, Musie; Alter, Galit

    2011-01-01

    In addition to neutralization, antibodies mediate other antiviral activities including antibody-dependent cellular-phagocytosis (ADCP), antibody dependent cellular-cytotoxicity (ADCC), as well as complement deposition. While it is established that progressive HIV infection is associated with reduced ADCC and ADCP, the underlying mechanism for this loss of function is unknown. Here we report considerable changes in FcR expression over the course of HIV infection on both mDCs and monocytes, including elevated FcγRI expression in acute HIV infection and reduced expression of FcγRII and FcγRIIIa in chronic HIV infection. Furthermore, selective blockade of FcγRII alone was associated with a loss in ADCP activity, suggesting that FcγRII plays a central role in modulating ADCP. Overall, HIV infection is associated with a number of changes in FcR expression on phagocytic cells that are associated with changes in their ability to respond to antibody-opsonized targets, potentially contributing to a failure in viral clearance in progressive HIV-1 infection. PMID:21565376

  2. An improved haemolytic plaque assay for the detection of cells secreting antibody to bacterial antigens

    DEFF Research Database (Denmark)

    Barington, T; Heilmann, C

    1992-01-01

    Recent advances in the development of conjugate polysaccharide vaccines for human use have stimulated interest in the use of assays detecting antibody-secreting cells (AbSC) with specificity for bacterial antigens. Here we present improved haemolytic plaque-forming cell (PFC) assays detecting Ab......SC with specificity for tetanus and diphtheria toxoid as well as for Haemophilus influenzae type b and pneumococcal capsular polysaccharides. These assays were found to be less time consuming, more economical and yielded 1.9-3.4-fold higher plaque numbers than traditional Jerne-type PFC assays. In the case of anti......-polysaccharide antibodies aggregation of secreted monomeric antibody (IgG) is critical for plaque formation and increases the avidity of binding to target cells....

  3. Unravelling the role of allo-antibodies and Transplant Injury

    Directory of Open Access Journals (Sweden)

    Yoshiko Matsuda

    2016-10-01

    Full Text Available Alloimmunity driving rejection in the context of solid organ transplantation can be grossly divided into mechanisms predominantly driven by either T cell-mediated rejection (TCMR or antibody-mediated rejection (ABMR, though the co-existence of both types of rejections can be seen in a variable number of sampled grafts. Acute TCMR can generally be well controlled by the establishment of effective immunosuppression 1, 2. Acute ABMR is a low frequency finding in the current era of blood group and HLA donor/recipient matching and the avoidance of engraftment in the context of high-titer, pre-formed donor specific antibodies. However, chronic ABMR remains a major complication resulting in the untimely loss of transplanted organs 3-10. The close relationship between donor-specific antibodies (DSAs and ABMR has been revealed by the highly sensitive detection of human leukocyte antigen (HLA antibodies 11-16. Injury to transplanted organs by activation of humoral immune reaction in the context of HLA identical transplants and the absence of donor specific antibodies (DSAs, strongly suggest the participation of non HLA (nHLA antibodies in ABMR (17-25. In this review, we discuss the genesis of ABMR in the context of HLA and nHLA antibodies and summarize strategies for ABMR management.

  4. Investigations on the protective role of passively transferred antibodies against avian metapneumovirus infection in turkeys.

    Science.gov (United States)

    Rubbenstroth, Dennis; Rautenschlein, Silke

    2009-12-01

    The avian metapneumovirus (aMPV) is the causative agent of an acute respiratory disease in turkeys, which causes considerable economic losses to the poultry industry. Currently attenuated live and inactivated vaccines are widely used to control the disease, but vaccine breaks are frequently observed. For improvement of current vaccination strategies it is necessary to gain enhanced knowledge of the immune mechanisms against aMPV infection. Field observations suggest that vaccine-induced aMPV-specific antibodies are not indicative for protection. In the present study we investigated the role of antibodies in protection of turkeys against aMPV. In two experiments, commercial turkey poults received aMPV-specific antibodies by intravenous injection. The antibody transfer resulted in increased antibody levels in the sera. Virus-specific antibodies were also detected on mucosal surfaces such as the trachea, conjunctivae and gall bladder. Turkeys were subsequently challenged with a virulent aMPV subtype A strain. Development of clinical signs, virus detection by polymerase chain reaction and histopathological changes of tracheal mucosa in challenged turkeys with and without passively transferred antibodies were comparable with each other. Our results suggest that humoral immunity does not provide sufficient protection against aMPV infection. Thus, the measurement of vaccine-induced aMPV antibody response may not be considered as an adequate indicator of vaccine efficacy. Further research on the protective role of cell-mediated immune mechanisms is necessary to improve current vaccine strategies.

  5. Heterogeneity of Polyneuropathy Associated with Anti-MAG Antibodies

    Directory of Open Access Journals (Sweden)

    Laurent Magy

    2015-01-01

    Full Text Available Polyneuropathy associated with IgM monoclonal gammopathy and anti-myelin associated glycoprotein (MAG antibodies is an immune-mediated demyelinating neuropathy. The pathophysiology of this condition is likely to involve anti-MAG antibody deposition on myelin sheaths of the peripheral nerves and it is supposed to be distinct from chronic inflammatory demyelinating neuropathy (CIDP, another immune-mediated demyelinating peripheral neuropathy. In this series, we have retrospectively reviewed clinical and laboratory findings from 60 patients with polyneuropathy, IgM gammopathy, and anti-MAG antibodies. We found that the clinical picture in these patients is highly variable suggesting a direct link between the monoclonal gammopathy and the neuropathy. Conversely, one-third of patients had a CIDP-like phenotype on electrodiagnostic testing and this was correlated with a low titer of anti-MAG antibodies and the absence of widening of myelin lamellae. Our data suggest that polyneuropathy associated with anti-MAG antibodies is less homogeneous than previously said and that the pathophysiology of the condition is likely to be heterogeneous as well with the self-antigen being MAG in most of the patients but possibly being another component of myelin in the others.

  6. Lymphocyte-dependent antibody-mediated cytotoxicity in Hashimoto thyroiditis

    Science.gov (United States)

    Calder, Elizabeth A.; Penhale, W. J.; McLeman, Dena; Barnes, E. W.; Irvine, W. J.

    1973-01-01

    In the presence of normal human lymphocytes, decomplemented sera from twentynine out of thirty-nine patients with Hashimoto thyroiditis caused significant lysis of thyroglobulin-coated chicken red blood cells, as estimated by the release of 51Cr; the mean% specific 51Cr release being 14·1 ± 1·9 (SEM). Serum from twenty-one control subjects studied concurrently caused no significant lysis of thyroglobulin-coated chicken red blood cells; the mean% specific 51Cr release being −1·6±0·7 (SEM). The degree of cytotoxicity correlated with the titre of thyroglobulin antibodies in the serum, determined by tanned red cell haemagglutination. The active component in the Hashimoto serum was localized in the 19S fraction, was unaffected by pre-absorption with anti-human IgM serum, but was neutralized by pre-absorption with anti-human IgG serum. These findings suggest that the cytotoxic activity of serum from patients with Hashimoto thyroiditis is due to the presence of thyroglobulin antibody of the IgG class in the form of complexes, either alone or with antigen. It is postulated that non-specific lymphocytes may play an important role in the pathogenesis of Hashimoto thyroiditis, being activated by the presence in the gland of thyroglobulin antibody, either alone or in the form of complexes attached to thyroid cells. PMID:4740445

  7. Immunization with Clinical HIV-1 Env Proteins Induces Broad Antibody Dependent Cellular Cytotoxicity-Mediating Antibodies in a Rabbit Vaccination Model

    DEFF Research Database (Denmark)

    Karlsson, Ingrid; Borggren, Marie; Jensen, Sanne Skov

    2018-01-01

    The induction of both neutralizing antibodies and non-neutralizing antibodies with effector functions, for example, antibody-dependent cellular cytotoxicity (ADCC), is desired in the search for effective vaccines against HIV-1. In the pursuit of novel immunogens capable of inducing an efficient a...

  8. Improvement of Anti-TNF-α Antibody-Induced Palmoplantar Pustular Psoriasis Using a 308-nm Excimer Light

    Directory of Open Access Journals (Sweden)

    Natsuko Iga

    2012-11-01

    Full Text Available Anti-tumor necrosis factor (TNF-α antibody is utilized in the treatment of a variety of chronic inflammatory conditions, including psoriasis. However, it can induce paradoxical development and/or exacerbation of psoriasis in the course of anti-TNF-α antibody treatment, which is sometimes refractory to conventional treatments. Herein, we report a case of refractory palmoplantar pustular psoriasis induced by anti-TNF-α antibody treatment, which was improved by treatment with a 308-nm excimer light. The 308-nm excimer light has less long-term risks than narrow-band UVB. The 308-nm excimer light may be a good therapeutic option for refractory psoriatic skin lesions induced by anti-TNF-α antibody therapy because of localized side effects without systemic problems, short length of treatment and low cumulative dosages of UV light.

  9. Human antibodies fix complement to inhibit Plasmodium falciparum invasion of erythrocytes and are associated with protection against malaria.

    Science.gov (United States)

    Boyle, Michelle J; Reiling, Linda; Feng, Gaoqian; Langer, Christine; Osier, Faith H; Aspeling-Jones, Harvey; Cheng, Yik Sheng; Stubbs, Janine; Tetteh, Kevin K A; Conway, David J; McCarthy, James S; Muller, Ivo; Marsh, Kevin; Anders, Robin F; Beeson, James G

    2015-03-17

    Antibodies play major roles in immunity to malaria; however, a limited understanding of mechanisms mediating protection is a major barrier to vaccine development. We have demonstrated that acquired human anti-malarial antibodies promote complement deposition on the merozoite to mediate inhibition of erythrocyte invasion through C1q fixation and activation of the classical complement pathway. Antibody-mediated complement-dependent (Ab-C') inhibition was the predominant invasion-inhibitory activity of human antibodies; most antibodies were non-inhibitory without complement. Inhibitory activity was mediated predominately via C1q fixation, and merozoite surface proteins 1 and 2 were identified as major targets. Complement fixation by antibodies was very strongly associated with protection from both clinical malaria and high-density parasitemia in a prospective longitudinal study of children. Ab-C' inhibitory activity could be induced by human immunization with a candidate merozoite surface-protein vaccine. Our findings demonstrate that human anti-malarial antibodies have evolved to function by fixing complement for potent invasion-inhibitory activity and protective immunity. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Monoclonal Antibodies, Derived from Humans Vaccinated with the RV144 HIV Vaccine Containing the HVEM Binding Domain of Herpes Simplex Virus (HSV) Glycoprotein D, Neutralize HSV Infection, Mediate Antibody-Dependent Cellular Cytotoxicity, and Protect Mice from Ocular Challenge with HSV-1.

    Science.gov (United States)

    Wang, Kening; Tomaras, Georgia D; Jegaskanda, Sinthujan; Moody, M Anthony; Liao, Hua-Xin; Goodman, Kyle N; Berman, Phillip W; Rerks-Ngarm, Supachai; Pitisuttithum, Punnee; Nitayapan, Sorachai; Kaewkungwal, Jaranit; Haynes, Barton F; Cohen, Jeffrey I

    2017-10-01

    The RV144 HIV vaccine trial included a recombinant HIV glycoprotein 120 (gp120) construct fused to a small portion of herpes simplex virus 1 (HSV-1) glycoprotein D (gD) so that the first 40 amino acids of gp120 were replaced by the signal sequence and the first 27 amino acids of the mature form of gD. This region of gD contains most of the binding site for HVEM, an HSV receptor important for virus infection of epithelial cells and lymphocytes. RV144 induced antibodies to HIV that were partially protective against infection, as well as antibodies to HSV. We derived monoclonal antibodies (MAbs) from peripheral blood B cells of recipients of the RV144 HIV vaccine and showed that these antibodies neutralized HSV-1 infection in cells expressing HVEM, but not the other major virus receptor, nectin-1. The MAbs mediated antibody-dependent cellular cytotoxicity (ADCC), and mice that received the MAbs and were then challenged by corneal inoculation with HSV-1 had reduced eye disease, shedding, and latent infection. To our knowledge, this is the first description of MAbs derived from human recipients of a vaccine that specifically target the HVEM binding site of gD. In summary, we found that monoclonal antibodies derived from humans vaccinated with the HVEM binding domain of HSV-1 gD (i) neutralized HSV-1 infection in a cell receptor-specific manner, (ii) mediated ADCC, and (iii) reduced ocular disease in virus-infected mice. IMPORTANCE Herpes simplex virus 1 (HSV-1) causes cold sores and neonatal herpes and is a leading cause of blindness. Despite many trials, no HSV vaccine has been approved. Nectin-1 and HVEM are the two major cellular receptors for HSV. These receptors are expressed at different levels in various tissues, and the role of each receptor in HSV pathogenesis is not well understood. We derived human monoclonal antibodies from persons who received the HIV RV144 vaccine that contained the HVEM binding domain of HSV-1 gD fused to HIV gp120. These antibodies were

  11. Fluorescently labeled chimeric anti-CEA antibody improves detection and resection of human colon cancer in a patient-derived orthotopic xenograft (PDOX) nude mouse model.

    Science.gov (United States)

    Metildi, Cristina A; Kaushal, Sharmeela; Luiken, George A; Talamini, Mark A; Hoffman, Robert M; Bouvet, Michael

    2014-04-01

    The aim of this study was to evaluate a new fluorescently labeled chimeric anti-CEA antibody for improved detection and resection of colon cancer. Frozen tumor and normal human tissue samples were stained with chimeric and mouse antibody-fluorophore conjugates for comparison. Mice with patient-derived orthotopic xenografts (PDOX) of colon cancer underwent fluorescence-guided surgery (FGS) or bright-light surgery (BLS) 24 hr after tail vein injection of fluorophore-conjugated chimeric anti-CEA antibody. Resection completeness was assessed using postoperative images. Mice were followed for 6 months for recurrence. The fluorophore conjugation efficiency (dye/mole ratio) improved from 3-4 to >5.5 with the chimeric CEA antibody compared to mouse anti-CEA antibody. CEA-expressing tumors labeled with chimeric CEA antibody provided a brighter fluorescence signal on frozen human tumor tissues (P = 0.046) and demonstrated consistently lower fluorescence signals in normal human tissues compared to mouse antibody. Chimeric CEA antibody accurately labeled PDOX colon cancer in nude mice, enabling improved detection of tumor margins for more effective FGS. The R0 resection rate increased from 86% to 96% with FGS compared to BLS. Improved conjugating efficiency and labeling with chimeric fluorophore-conjugated antibody resulted in better detection and resection of human colon cancer in an orthotopic mouse model. © 2013 Wiley Periodicals, Inc.

  12. Improved production and function of llama heavy chain antibody fragments by molecular evolution

    NARCIS (Netherlands)

    Linden, van der R.H.; Geus, de B.; Frenken, G.J.; Peters, H.; Verrips, C.T.

    2000-01-01

    The aim of this study was to improve production level of llama heavy chain antibody fragments (V (HH)) in Saccharomyces cerevisiae while retaining functional characteristics. For this purpose, the DNA shuffling technique was used on llama V (HH) fragments specific for the azo-dye reactive red-6. In

  13. Outside-in HLA class I signaling regulates ICAM-1 clustering and endothelial cell-monocyte interactions via mTOR in transplant antibody-mediated rejection.

    Science.gov (United States)

    Salehi, Sahar; Sosa, Rebecca A; Jin, Yi-Ping; Kageyama, Shoichi; Fishbein, Michael C; Rozengurt, Enrique; Kupiec-Weglinski, Jerzy W; Reed, Elaine F

    2018-05-01

    Antibody-mediated rejection (AMR) resulting in transplant allograft vasculopathy (TAV) is the major obstacle for long-term survival of solid organ transplants. AMR is caused by donor-specific antibodies to HLA, which contribute to TAV by initiating outside-in signaling transduction pathways that elicit monocyte recruitment to activated endothelium. Mechanistic target of rapamycin (mTOR) inhibitors can attenuate TAV; therefore, we sought to understand the mechanistic underpinnings of mTOR signaling in HLA class I Ab-mediated endothelial cell activation and monocyte recruitment. We used an in vitro model to assess monocyte binding to HLA I Ab-activated endothelial cells and found mTOR inhibition reduced ezrin/radixin/moesin (ERM) phosphorylation, intercellular adhesion molecule 1 (ICAM-1) clustering, and monocyte firm adhesion to HLA I Ab-activated endothelium. Further, in a mouse model of AMR, in which C57BL/6. RAG1 -/- recipients of BALB/c cardiac allografts were passively transferred with donor-specific MHC I antibodies, mTOR inhibition significantly reduced vascular injury, ERM phosphorylation, and macrophage infiltration of the allograft. Taken together, these studies indicate mTOR inhibition suppresses ERM phosphorylation in endothelial cells, which impedes ICAM-1 clustering in response to HLA class I Ab and prevents macrophage infiltration into cardiac allografts. These findings indicate a novel therapeutic application for mTOR inhibitors to disrupt endothelial cell-monocyte interactions during AMR. © 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.

  14. Biomimetic Nanosponges for Treating Antibody-Mediated Autoimmune Diseases.

    Science.gov (United States)

    Jiang, Yao; Fang, Ronnie H; Zhang, Liangfang

    2018-04-18

    Autoimmune diseases are characterized by overactive immunity, where the body's defense system launches an attack against itself. If left unchecked, this can result in the destruction of healthy tissue and significantly affect patient well-being. In the case of type II autoimmune hypersensitivities, autoreactive antibodies attack the host's own cells or extracellular matrix. Current clinical treatment modalities for managing this class of disease are generally nonspecific and face considerable limitations. In this Topical Review, we cover emerging therapeutic strategies, with an emphasis on novel nanomedicine platforms. Specifically, the use of biomimetic cell membrane-coated nanosponges that are capable of specifically binding and neutralizing pathological antibodies will be explored. There is significant untapped potential in the application of nanotechnology for the treatment of autoimmune diseases, and continued development along this line may help to eventually change the clinical landscape.

  15. Updates on antibody functions in Mycobacterium tuberculosis infection and their relevance for developing a vaccine against tuberculosis.

    Science.gov (United States)

    Achkar, Jacqueline M; Prados-Rosales, Rafael

    2018-04-12

    A more effective vaccine to control tuberculosis (TB), a major global public health problem, is urgently needed. Current vaccine candidates focus predominantly on eliciting cell-mediated immunity but other arms of the immune system also contribute to protection against TB. We review here recent studies that enhance our current knowledge of antibody-mediated functions against Mycobacterium tuberculosis. These findings, which contribute to the increasing evidence that antibodies have a protective role against TB, include demonstrations that firstly distinct human antibody Fc glycosylation patterns, found in latent M. tuberculosis infection but not in active TB, influence the efficacy of the host to control M. tuberculosis infection, secondly antibody isotype influences human antibody functions, and thirdly that antibodies targeting M. tuberculosis surface antigens are protective. We discuss these findings in the context of TB vaccine development and highlight the need for further research on antibody-mediated immunity in M. tuberculosis infection. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Protection by meningococcal outer membrane protein PorA-specific antibodies and a serogroup B capsular polysaccharide-specific antibody in complement-sufficient and C6-deficient infant rats.

    Science.gov (United States)

    Toropainen, Maija; Saarinen, Leena; Vidarsson, Gestur; Käyhty, Helena

    2006-05-01

    The relative contributions of antibody-induced complement-mediated bacterial lysis and antibody/complement-mediated phagocytosis to host immunity against meningococcal infections are currently unclear. Further, the in vivo effector functions of antibodies may vary depending on their specificity and Fc heavy-chain isotype. In this study, a mouse immunoglobulin G2a (mIgG2a) monoclonal antibody (MN12H2) to meningococcal outer membrane protein PorA (P1.16), its human IgG subclass derivatives (hIgG1 to hIgG4), and an mIgG2a monoclonal antibody (Nmb735) to serogroup B capsular polysaccharide (B-PS) were evaluated for passive protection against meningococcal serogroup B strain 44/76-SL (B:15:P1.7,16) in an infant rat infection model. Complement component C6-deficient (PVG/c-) rats were used to assess the importance of complement-mediated bacterial lysis for protection. The PorA-specific parental mIgG2a and the hIgG1 to hIgG3 derivatives all induced efficient bactericidal activity in vitro in the presence of human or infant rat complement and augmented bacterial clearance in complement-sufficient HsdBrlHan:WIST rats, while the hIgG4 was unable to do so. In C6-deficient PVG/c- rats, lacking complement-mediated bacterial lysis, the augmentation of bacterial clearance by PorA-specific mIgG2a and hIgG1 antibodies was impaired compared to that in the syngeneic complement-sufficient PVG/c+ rat strain. This was in contrast to the case for B-PS-specific mIgG2a, which conferred similar protective activity in both rat strains. These data suggest that while anti-B-PS antibody can provide protection in the infant rats without membrane attack complex formation, the protection afforded by anti-PorA antibody is more dependent on the activation of the whole complement pathway and subsequent bacterial lysis.

  17. Protective antibodies against placental malaria and poor outcomes during pregnancy, Benin

    DEFF Research Database (Denmark)

    Ndam, Nicaise Tuikue; Denoeud-Ndam, Lise; Doritchamou, Justin

    2015-01-01

    Placental malaria is caused by Plasmodium falciparum-infected erythrocytes that bind to placental tissue. Binding is mediated by VAR2CSA, a parasite antigen coded by the var gene, which interacts with chondroitin sulfate A (CSA). Consequences include maternal anemia and fetal growth retardation....... Antibody-mediated immunity to placental malaria is acquired during successive pregnancies, but the target of VAR2CSA-specific protective antibodies is unclear. We assessed VAR2CSA-specific antibodies in pregnant women and analyzed their relationships with protection against placental infection, preterm...... birth, and low birthweight. Antibody responses to the N-terminal region of VAR2CSA during early pregnancy were associated with reduced risks for infections and low birthweight. Among women infected during pregnancy, an increase in CSA binding inhibition was associated with reduced risks for placental...

  18. Antibody engineering using phage display with a coiled-coil heterodimeric Fv antibody fragment.

    Directory of Open Access Journals (Sweden)

    Xinwei Wang

    Full Text Available A Fab-like antibody binding unit, ccFv, in which a pair of heterodimeric coiled-coil domains was fused to V(H and V(L for Fv stabilization, was constructed for an anti-VEGF antibody. The anti-VEGF ccFv showed the same binding affinity as scFv but significantly improved stability and phage display level. Furthermore, phage display libraries in the ccFv format were constructed for humanization and affinity maturation of the anti-VEGF antibody. A panel of V(H frameworks and V(H-CDR3 variants, with a significant improvement in affinity and expressibility in both E. coli and yeast systems, was isolated from the ccFv phage libraries. These results demonstrate the potential application of the ccFv antibody format in antibody engineering.

  19. Intracellular trafficking of new anticancer therapeutics: antibody-drug conjugates.

    Science.gov (United States)

    Kalim, Muhammad; Chen, Jie; Wang, Shenghao; Lin, Caiyao; Ullah, Saif; Liang, Keying; Ding, Qian; Chen, Shuqing; Zhan, Jinbiao

    2017-01-01

    Antibody-drug conjugate (ADC) is a milestone in targeted cancer therapy that comprises of monoclonal antibodies chemically linked to cytotoxic drugs. Internalization of ADC takes place via clathrin-mediated endocytosis, caveolae-mediated endocytosis, and pinocytosis. Conjugation strategies, endocytosis and intracellular trafficking optimization, linkers, and drugs chemistry present a great challenge for researchers to eradicate tumor cells successfully. This inventiveness of endocytosis and intracellular trafficking has given considerable momentum recently to develop specific antibodies and ADCs to treat cancer cells. It is significantly advantageous to emphasize the endocytosis and intracellular trafficking pathways efficiently and to design potent engineered conjugates and biological entities to boost efficient therapies enormously for cancer treatment. Current studies illustrate endocytosis and intracellular trafficking of ADC, protein, and linker strategies in unloading and also concisely evaluate practically applicable ADCs.

  20. In vivo instability of reduction-mediated 99mTc-labeled monoclonal antibody

    International Nuclear Information System (INIS)

    Sakahara, Harumi; Saga, Tsuneo; Endo, Keigo

    1993-01-01

    A murine monoclonal antibody that reacts with human osteogenic sarcoma (OST7) was reduced and directly labelled with 99m Tc without any loss of immunoreactivity. No fragmentation of the antibody was detected by high performance liquid chromatography after the labelling. However, SDS-PAGE analysis of the labelled antibody demonstrated the presence of low molecular weight species. Although more than 95% of the radioactivity remained bound at the antibody after incubation with human serum for 24 h, 99m Tc-labelled OST7 was cleared faster from the circulation than 125 I-labelled OST7 or 111 In-labelled OST7 in mice. (author)

  1. How do Housing Subsidies Improve Quality of Life Among Homeless Adults? A Mediation Analysis.

    Science.gov (United States)

    O'Connell, Maria; Sint, Kyaw; Rosenheck, Robert

    2018-03-01

    Supported housing, combining rent subsidies with intensive case management, is associated with improvements in quality of life of homeless adults, but factors mediating their impact on quality of life have not been studied. Twelve-month outcome data from a randomized trial of the Housing and Urban Development- Veterans Affairs Supported Housing program (HUD-VASH) showed that access to a housing rent subsidy plus intensive case management (ICM) was associated with greater improvement in subjective quality of life than ICM alone. Multiple mediation analyses were applied to identify variables that significantly mediated the relationship between receipt of housing voucher and improvements in quality of life. Significant mediating covariates were those whose 95% bias-corrected confidence intervals, when added to the model predicting improvement in quality of life, did not overlap zero. Increases in the number of days housed, size of social network, and availability of emotional support appear to mediate improvement in quality of life and account for 71% of the benefit attributable to having a rent subsidy. Improvement in subjective quality of life though housing subsidies is mediated by gains in both material and psychosocial factors. Mediating factors deserve special attention in supported housing services. © Society for Community Research and Action 2018.

  2. DNA-mediated strand displacement facilitates sensitive electronic detection of antibodies in human serums.

    Science.gov (United States)

    Dou, Baoting; Yang, Jianmei; Shi, Kai; Yuan, Ruo; Xiang, Yun

    2016-09-15

    We describe here the development of a sensitive and convenient electronic sensor for the detection of antibodies in human serums. The sensor is constructed by self-assembly formation of a mixed monolayer containing the small molecule epitope conjugated double stranded DNA probes on gold electrode. The target antibody binds the epitope on the dsDNA probe and lowers the melting temperature of the duplex, which facilitates the displacement of the antibody-linked strand of the duplex probe by an invading methylene blue-tagged single stranded DNA (MB-ssDNA) through the strand displacement reaction and leads to the capture of many MB-ssDNA on the sensor surface. Subsequent electrochemical oxidation of the methylene blue labels results in amplified current response for sensitive monitoring of the antibodies. The antibody assay conditions are optimized and the sensor exhibits a linear range between 1.0 and 25.0nM with a detection limit of 0.67nM for the target antibody. The sensor is also selective and can be employed to detect the target antibodies in human serum samples. With the advantages of using small molecule epitope as the antibody recognition element over traditional antigen, the versatile manipulability of the DNA probes and the unique properties of the electrochemical transduction technique, the developed sensor thus hold great potential for simple and sensitive detection of different antibodies and other proteins in real samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Antibody or Antibody Fragments : Implications for Molecular Imaging and Targeted Therapy of Solid Tumors

    NARCIS (Netherlands)

    Xenaki, Katerina T; Oliveira, Sabrina; van Bergen En Henegouwen, Paul M P

    2017-01-01

    The use of antibody-based therapeutics has proven very promising for clinical applications in cancer patients, with multiple examples of antibodies and antibody-drug conjugates successfully applied for the treatment of solid tumors and lymphomas. Given reported recurrence rates, improvements are

  4. [A spectrum of neurological diseases with anti-VGKC antibody].

    Science.gov (United States)

    Arimura, Kimiyoshi; Watanabe, Osamu; Nagado, Tatsui

    2007-11-01

    Anti-VGKC antibody causing peripheral nerve hyperexcitability is already an established clinical entity. Recently, many patients with non-herpetic limbic encephalitis (NHLE) with anti-VGKC antibody have been reported. The characteristic clinical features are low serum Na+ concentration and good response to immunotherapy. Anti-VGK antibody positive NHLE is relatively frequent among immune-mediated NHLE. It is important to know that this disease is responsive to immunotherapy. Furthermore, anti-VGKC antibody is also positive in some intractable epilepsies. These findings suggest that anti-VGKC is correlated with hyperexcitability in both the peripheral and central nervous system and that the spectrum of anti-VGKC antibody syndrome is now expanding.

  5. Toll-like receptor activation enhances cell-mediated immunity induced by an antibody vaccine targeting human dendritic cells

    Directory of Open Access Journals (Sweden)

    Berger Marc A

    2007-01-01

    Full Text Available Abstract Previously, we have successfully targeted the mannose receptor (MR expressed on monocyte-derived dendritic cells (DCs using a fully human MR-specific antibody, B11, as a vehicle to deliver whole protein tumor antigens such as the human chorionic gonadotropin hormone (hCGβ. Since MRs play a role in bridging innate immunity with adaptive immunity we have explored several toll-like receptor (TLR-specific ligands that may synergize with MR targeting and be applicable as adjuvants in the clinic. We demonstrate that antigen-specific helper and cytolytic T cells from both healthy donors and cancer patients were effectively primed with B11-hCGβ-treated autologous DCs when a combination of one or several TLR ligands is used. Specifically, concomitant signaling of DCs via TLR3 with dsRNA (poly I:C and DC TLR 7/8 with Resiquimod (R-848, respectively, elicited efficient antigen presentation-mediated by MR-targeting. We demonstrate that MR and TLRs contribute towards maturation and activation of DCs by a mechanism that may be driven by a combination of adjuvant and antibody vaccines that specifically deliver antigenic targets to DCs.

  6. Multifunctional Dendrimer-templated Antibody Presentation on Biosensor Surfaces for Improved Biomarker Detection.

    Science.gov (United States)

    Han, Hye Jung; Kannan, Rangaramanujam M; Wang, Sunxi; Mao, Guangzhao; Kusanovic, Juan Pedro; Romero, Roberto

    2010-02-08

    Dendrimers, with their well-defined globular shape and a high density of functional groups, are ideal nanoscale materials for templating sensor surfaces. This work exploits dendrimers as a versatile platform for capturing biomarkers with improved sensitivity and specificity. Synthesis, characterization, fabrication, and functional validation of the dendrimer-based assay platform are described. Bifunctional hydroxyl/thiol functionalized G4-polyamidoamine (PAMAM) dendrimer is synthesized and immobilized on to the polyethylene-glycol (PEG)-functionalized assay plate by coupling PEG-maleimide and dendrimer thiol groups. Simultaneously, part of the dendrimer thiol groups are converted to hydrazide functionalities. The resulting dendrimer-modified surface is coupled to the capture antibody in the Fc region of the oxidized antibody. This preserves the orientation flexibility of the antigen binding region (Fv) of the antibody. To validate the approach, the fabricated plates are further used as a solid phase for developing a sandwich type ELISA to detect IL-6 and IL-1β, important biomarkers for early stages of chorioamnionitis. The dendrimer-modified plate provides assays with significantly enhanced sensitivity, lower nonspecific adsorption, and a detection limit of 0.13 pg ml -1 for IL-6 luminol detection and 1.15 pg ml -1 for IL-1β TMB detection, which are significantly better than those for the traditional ELISA. The assays were validated in human serum samples from normal (non-pregnant) woman and pregnant women with pyelonephritis. The specificity and the improved sensitivity of the dendrimer-based capture strategy could have significant implications for the detection of a wide range of cytokines and biomarkers since the capture strategy could be applied to multiplex microbead assays, conductometric immunosensors and field effect biosensors.

  7. Antibody-dependent cellular cytotoxicity and neutralizing activity in sera of HIV-1-infected mothers and their children.

    Science.gov (United States)

    Broliden, K; Sievers, E; Tovo, P A; Moschese, V; Scarlatti, G; Broliden, P A; Fundaro, C; Rossi, P

    1993-01-01

    The prognostic and protective role of antibodies mediating cellular cytotoxicity (ADCC) and neutralization was evaluated in sera of HIV-1-infected mothers and their consecutively followed children. The presence and titres of ADCC mediating and/or neutralizing antibodies in maternal sera did not predict HIV-1 infection in their respective children. No significant difference in the sera from the children was seen when comparing the presence of neutralizing antibodies between the uninfected and infected children. Stratification of the infected group according to clinical status revealed differences. Only one of 24 AIDS patients had a high neutralizing titre against IIIB. Four patients had a very low titre and the remaining had no detectable neutralizing antibodies at all. In contrast, 10/17 infected non-AIDS children had neutralizing antibodies. Similarly, no significant difference was seen when comparing the presence of ADCC-mediating antibodies between the uninfected and the infected group of children. However, a significantly higher frequency of ADCC was seen in the seropositive non-AIDS children compared with the AIDS children. This study clearly shows that the presence of antibodies mediating ADCC and neutralization in infected children, 0-2 years old, is associated with a better clinical status and delayed disease progression. PMID:8324904

  8. The interfacial character of antibody paratopes: analysis of antibody-antigen structures.

    Science.gov (United States)

    Nguyen, Minh N; Pradhan, Mohan R; Verma, Chandra; Zhong, Pingyu

    2017-10-01

    In this study, computational methods are applied to investigate the general properties of antigen engaging residues of a paratope from a non-redundant dataset of 403 antibody-antigen complexes to dissect the contribution of hydrogen bonds, hydrophobic, van der Waals contacts and ionic interactions, as well as role of water molecules in the antigen-antibody interface. Consistent with previous reports using smaller datasets, we found that Tyr, Trp, Ser, Asn, Asp, Thr, Arg, Gly, His contribute substantially to the interactions between antibody and antigen. Furthermore, antibody-antigen interactions can be mediated by interfacial waters. However, there is no reported comprehensive analysis for a large number of structured waters that engage in higher ordered structures at the antibody-antigen interface. From our dataset, we have found the presence of interfacial waters in 242 complexes. We present evidence that suggests a compelling role of these interfacial waters in interactions of antibodies with a range of antigens differing in shape complementarity. Finally, we carry out 296 835 pairwise 3D structure comparisons of 771 structures of contact residues of antibodies with their interfacial water molecules from our dataset using CLICK method. A heuristic clustering algorithm is used to obtain unique structural similarities, and found to separate into 368 different clusters. These clusters are used to identify structural motifs of contact residues of antibodies for epitope binding. This clustering database of contact residues is freely accessible at http://mspc.bii.a-star.edu.sg/minhn/pclick.html. minhn@bii.a-star.edu.sg, chandra@bii.a-star.edu.sg or zhong_pingyu@immunol.a-star.edu.sg. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  9. Tumor imaging with monoclonal antibodies

    International Nuclear Information System (INIS)

    Haisma, H.; Hilgers, J.

    1987-01-01

    Many monoclonal antibodies directed against tumor-associated antigens have been identified, but so far none of these are tumor specific. Polyclonal and monoclonal antibodies have been used for imaging of a wide variety of tumors with success. Radiolabeling of antibody is usually done with iodine isotopes of which 123 I is the best candidate for radioimmunodetection purposes. The labeling of antibodies through chelates makes it possible to use metal radioisotopes like 111 In, which is the best radioisotope for imaging with monoclonal antibodies due to its favorable half-life of 2.5 days. Usually imaging cannot be performed within 24 h after injection, but clearance of antibody can be increased by using F(ab) 2 of Fab. Another approach is to clear non-bound antibody by a second antibody, directed against the first. The detection limit of immunoimaging is about 2 cm, but will be improved by tomography or SPECT. There is still a high false positive and false negative rate, which makes it impossible to use radioimmunodetection as the only technique for diagnosis of tumors. In combination with other detection techniques, tumor imaging with monoclonal antibodies can improve diagnosis. 44 refs.; 3 tabs

  10. Induction of CD4 suppressor T cells with anti-Leu-8 antibody

    International Nuclear Information System (INIS)

    Kanof, M.E.; Strober, W.; James, S.P.

    1987-01-01

    To characterize the conditions under which CD4 T cells suppress polyclonal immunoglobulin synthesis, we investigated the capacity of CD4 T cells that coexpress the surface antigen recognized by the monoclonal antibody anti-Leu-8 to mediate suppression. In an in vitro system devoid of CD8 T cells, CD4, Leu-8+ T cells suppressed pokeweed mitogen-induced immunoglobulin synthesis. Similarly, suppressor function was induced in unfractionated CD4 T cell populations after incubation with anti-Leu-8 antibody under cross-linking conditions. This induction of suppressor function by anti-Leu-8 antibody was not due to expansion of the CD4, Leu-8+ T cell population because CD4 T cells did not proliferate in response to anti-Leu-8 antibody. However, CD4, Leu-8+ T cell-mediated suppression was radiosensitive. Finally, CD4, Leu-8+ T cells do not inhibit immunoglobulin synthesis when T cell lymphokines were used in place of helper CD4 T cells (CD4, Leu-8- T cells), suggesting that CD4 T cell-mediated suppression occurs at the T cell level. We conclude that CD4 T cells can be induced to suppress immunoglobulin synthesis by modulation of the membrane antigen recognized by anti-Leu-8 antibody

  11. Increased infectivity in human cells and resistance to antibody-mediated neutralization by truncation of the SIV gp41 cytoplasmic tail

    Directory of Open Access Journals (Sweden)

    Takeo eKuwata

    2013-05-01

    Full Text Available The role of antibodies in protecting the host from human immunodeficiency virus type 1 (HIV-1 infection is of considerable interest, particularly because the RV144 trial results suggest that antibodies contribute to protection. Although infection of nonhuman primates with simian immunodeficiency virus (SIV is commonly used as an animal model of HIV-1 infection, the viral epitopes that elicit potent and broad neutralizing antibodies to SIV have not been identified. We isolated a monoclonal antibody (MAb B404 that potently and broadly neutralizes various SIV strains. B404 targets a conformational epitope comprising the V3 and V4 loops of Env that intensely exposed when Env binds CD4. B404-resistant variants were obtained by passaging viruses in the presence of increasing concentration of B404 in PM1/CCR5 cells. Genetic analysis revealed that the Q733stop mutation, which truncates the cytoplasmic tail of gp41, was the first major substitution in Env during passage. The maximal inhibition by B404 and other MAbs were significantly decreased against a recombinant virus with a gp41 truncation compared with the parental SIVmac316. This indicates that the gp41 truncation was associated with resistance to antibody-mediated neutralization. The infectivities of the recombinant virus with the gp41 truncation were 7900-fold, 1000-fold, and 140-fold higher than those of SIVmac316 in PM1, PM1/CCR5, and TZM-bl cells, respectively. Immunoblotting analysis revealed that the gp41 truncation enhanced the incorporation of Env into virions. The effect of the gp41 truncation on infectivity was not obvious in the HSC-F macaque cell line, although the resistance of viruses harboring the gp41 truncation to neutralization was maintained. These results suggest that viruses with a truncated gp41 cytoplasmic tail were selected by increased infectivity in human cells and by acquiring resistance to neutralizing antibody.

  12. Immune-Mediated Neutropenia and Thrombocytopenia in a Patient with Ulcerative Colitis: An Unusual Hematological Association with IBD

    Directory of Open Access Journals (Sweden)

    Young-In Kim

    1995-01-01

    Full Text Available Hematological manifestations of inflammatory bowel disease (IBD are well described in the literature. However, the combination of immune-mediated neutropenia and thrombocytopenia has only been reported once in association with IBD. A case is reported of immune-mediated neutropenia and thrombocytopenia in a patient with ulcerative colitis during a relapse. No obvious causes of these hematological abnormalities were found in the patient despite an exhaustive search. An immune-mediated process was confirmed by positive antineutrophil antibody and platelet-associated antibody in the patient’s serum, and the demonstration of binding of the patient’s immunoglobulin G to autologous neutrophils. The patient was treated with high-dose steroid, intravenous gamma-globulin and eventually splenectomy. The platelet count subsequently normalized; although the severe neutropenia recurred, it has subsequently improved without further treatment. Although a definitive cause-effect relationship cannot be established, the immune-mediated neutropenia and thrombocytopenia may be an unusual hematological manifestation associated with ulcerative colitis.

  13. Design of therapeutic vaccines as a novel antibody therapy for cardiovascular diseases.

    Science.gov (United States)

    Nakagami, Hironori

    2017-09-01

    Vaccines are primarily used worldwide as a preventive medicine for infectious diseases and have recently been applied to cancer. We and others have developed therapeutic vaccines designed for cardiovascular diseases that are notably different from previous vaccines. In the case of cancer vaccines, a specific protein in cancer cells is a target antigen, and the activation of cytotoxic T cells (CTL) is required to kill and remove the antigen-presenting cancer cells. Our therapeutic vaccines work against hypertension by targeting angiotensin II (Ang II) as the antigen, which is an endogenous hormone. Therapeutic vaccines must avoid CTL activation and induce the blocking antibodies for Ang II. The goal of our therapeutic vaccine for cardiovascular diseases is to induce the specific antibody response toward the target protein without inducing T-cell or antibody-mediated inflammation through the careful selection of the target antigen, carrier protein and adjuvants. The goal of our therapeutic vaccine is similar to that of antibody therapy. Recently, multiple antibody-based drugs have been developed for cancer, immune-related diseases, and dyslipidemia, which are efficient but expensive. If the effect of a therapeutic vaccine is nearly equivalent to antibody therapy as an alternative approach, the lower medical cost and improvement in drug adherence can be advantages of therapeutic vaccines. In this review, we will describe our concept of therapeutic vaccines for cardiovascular diseases and the future directions of therapeutic vaccines as novel antibody therapies. Copyright © 2017. Published by Elsevier Ltd.

  14. Detection of antibodies in neuropathy patients by synthetic GM1 mimics

    NARCIS (Netherlands)

    Pukin, A.; Jacobs, B.C.; Tio-Gillen, A.P.; Gilbert, M.; Endtz, H.P.; Belkum, van A.; Visser, G.M.; Zuilhof, H.

    2011-01-01

    Antibodies to the ganglioside GM1 are associated with various forms of acute and chronic immune-mediated neuropathy, including Guillain–Barré syndrome (GBS) and multifocal motor neuropathy. In diagnostics and research, these antibodies are usually detected by GM1 preparations derived from bovine

  15. Comprehensive characterization of glutamine synthetase-mediated selection for the establishment of recombinant CHO cells producing monoclonal antibodies.

    Science.gov (United States)

    Noh, Soo Min; Shin, Seunghyeon; Lee, Gyun Min

    2018-03-29

    To characterize a glutamine synthetase (GS)-based selection system, monoclonal antibody (mAb) producing recombinant CHO cell clones were generated by a single round of selection at various methionine sulfoximine (MSX) concentrations (0, 25, and 50 μM) using two different host cell lines (CHO-K1 and GS-knockout CHO). Regardless of the host cell lines used, the clones selected at 50 μM MSX had the lowest average specific growth rate and the highest average specific production rates of toxic metabolic wastes, lactate and ammonia. Unlike CHO-K1, high producing clones could be generated in the absence of MSX using GS-knockout CHO with an improved selection stringency. Regardless of the host cell lines used, the clones selected at various MSX concentrations showed no significant difference in the GS, heavy chain, and light chain gene copies (P > 0.05). Furthermore, there was no correlation between the specific mAb productivity and these three gene copies (R 2  ≤ 0.012). Taken together, GS-mediated gene amplification does not occur in a single round of selection at a MSX concentration up to 50 μM. The use of the GS-knockout CHO host cell line facilitates the rapid generation of high producing clones with reduced production of lactate and ammonia in the absence of MSX.

  16. Focal CA3 hippocampal subfield atrophy following LGI1 VGKC-complex antibody limbic encephalitis

    OpenAIRE

    Miller, T; Chong, T; Aimola Davies, A; Ng, T; Johnson, M; Irani, S; Vincent, A; Husain, M; Jacob, S; Maddison, P; Kennard, C; Gowland, P; Rosenthal, C

    2017-01-01

    Magnetic resonance imaging has linked chronic voltage-gated potassium channel (VGKC) complex antibody-mediated limbic encephalitis with generalized hippocampal atrophy. However, autoantibodies bind to specific rodent hippocampal subfields. Here, human hippocampal subfield (subiculum, cornu ammonis 1-3, and dentate gyrus) targets of immunomodulation-treated LGI1 VGKC-complex antibody-mediated limbic encephalitis were investigated using in vivo ultra-high resolution (0.39 × 0....

  17. Antibody and B cell responses to Plasmodium sporozoites

    Directory of Open Access Journals (Sweden)

    Johanna N Dups

    2014-11-01

    Full Text Available Antibodies are capable of blocking infection of the liver by Plasmodium sporozoites. Accordingly the induction of anti-sporozoite antibodies is a major aim of various vaccine approaches to malaria. In recent years our knowledge of the specificity and quantities of antibodies required for protection has been greatly expanded by clinical trials of various whole sporozoite and subunit vaccines. Moreover, the development of humanized mouse models and transgenic parasites have also aided our ability to assess the specificity of antibodies and their ability to block infection. Nonetheless, considerable gaps remain in our knowledge - in particular in understanding what antigens are recognized by infection blocking antibodies and in knowing how we can induce robust, long-lived antibody responses. Maintaining high levels of circulating antibodies is likely to be of primary importance, as antibodies must block infection in the short time it takes for sporozoites to reach the liver from the skin. It is clear that a better understanding of the development of protective B cell-mediated immunity will aid the development and refinement of malaria vaccines.

  18. Targeting Antibodies to Carbon Nanotube Field Effect Transistors by Pyrene Hydrazide Modification of Heavy Chain Carbohydrates

    Directory of Open Access Journals (Sweden)

    Steingrimur Stefansson

    2012-01-01

    Full Text Available Many carbon nanotube field-effect transistor (CNT-FET studies have used immobilized antibodies as the ligand binding moiety. However, antibodies are not optimal for CNT-FET detection due to their large size and charge. Their size can prevent ligands from reaching within the Debye length of the CNTs and a layer of charged antibodies on the circuits can drown out any ligand signal. In an attempt to minimize the antibody footprint on CNT-FETs, we examined whether pyrene hydrazide modification of antibody carbohydrates could reduce the concentration required to functionalize CNT circuits. The carbohydrates are almost exclusively on the antibody Fc region and this site-specific modification could mediate uniform antibody orientation on the CNTs. We compared the hydrazide modification of anti-E. coli O157:H7 polyclonal antibodies to pyrenebutanoic acid succinimidyl ester-coated CNTs and carbodiimide-mediated antibody CNT attachment. Our results show that the pyrene hydrazide modification was superior to those methods with respect to bacteria detection and less than 1 nM labeled antibody was required to functionalize the circuits.

  19. IgM-mediated opsonization and cytotoxicity in the shark.

    Science.gov (United States)

    McKinney, E C; Flajnik, M F

    1997-02-01

    Two types of cytotoxic reactions have been observed using cells from the nurse shark: spontaneous cytotoxicity mediated by cells of the macrophage lineage and antibody-dependent killing carried out by a different effector cell population. Previous data showed that removal of phagocytic cells using iron particles abolished macrophage-mediated killing, but not antibody-dependent reactions. The current study used single cell assays and showed that the effector of antibody-driven reactions was the neutrophil. Surprisingly, the mechanism of killing was shown to be phagocytosis mediated by both 7S and 19S immunoglobulin M (IgM). Reactions proceeded with as little as 0.01 microg of purified 19S or 7S IgM and were complete within 4-6 h. In contrast, purified immunoglobulin did not adsorb to macrophages and had no effect on target cell binding or cytotoxicity. Pretreatment of cells with cytochalasin D abolished the phagocytic reaction, but not spontaneous cytotoxicity. These data show that antibody-mediated killing results from opsonization and phagocytosis; the mechanism of macrophage killing is currently unknown. In addition, these data show that the shark neutrophil, not the macrophage lineage, carries a receptor for Fc mu.

  20. MP-4 Contributes to Snake Venom Neutralization by Mucuna pruriens Seeds through an Indirect Antibody-mediated Mechanism*

    Science.gov (United States)

    Kumar, Ashish; Gupta, Chitra; Salunke, Dinakar M.

    2016-01-01

    Mortality due to snakebite is a serious public health problem, and available therapeutics are known to induce debilitating side effects. Traditional medicine suggests that seeds of Mucuna pruriens can provide protection against the effects of snakebite. Our aim is to identify the protein(s) that may be important for snake venom neutralization and elucidate its mechanism of action. To this end, we have identified and purified a protein from M. pruriens, which we have named MP-4. The full-length polypeptide sequence of MP-4 was obtained through N-terminal sequencing of peptide fragments. Sequence analysis suggested that the protein may belong to the Kunitz-type protease inhibitor family and therefore may potentially neutralize the proteases present in snake venom. Using various structural and biochemical tools coupled with in vivo assays, we are able to show that MP-4 does not afford direct protection against snake venom because it is actually a poor inhibitor of serine proteases. Further experiments showed that antibodies generated against MP-4 cross-react with the whole venom and provide protection to mice against Echis carinatus snake venom. This study shows that the MP-4 contributes significantly to the snake venom neutralization activity of M. pruriens seeds through an indirect antibody-mediated mechanism. PMID:26987900

  1. Development of antibody-modified chitosan nanoparticles for the targeted delivery of siRNA across the blood-brain barrier as a strategy for inhibiting HIV replication in astrocytes.

    Science.gov (United States)

    Gu, Jijin; Al-Bayati, Karam; Ho, Emmanuel A

    2017-08-01

    RNA interference (RNAi)-mediated gene silencing offers a novel treatment and prevention strategy for human immunodeficiency virus (HIV) infection. HIV was found to infect and replicate in human brain cells and can cause neuroinfections and neurological deterioration. We designed dual-antibody-modified chitosan/small interfering RNA (siRNA) nanoparticles to deliver siRNA across the blood-brain barrier (BBB) targeting HIV-infected brain astrocytes as a strategy for inhibiting HIV replication. We hypothesized that transferrin antibody and bradykinin B2 antibody could specifically bind to the transferrin receptor (TfR) and bradykinin B2 receptor (B2R), respectively, and deliver siRNA across the BBB into astrocytes as potential targeting ligands. In this study, chitosan nanoparticles (CS-NPs) were prepared by a complex coacervation method in the presence of siRNA, and antibody was chemically conjugated to the nanoparticles. The antibody-modified chitosan nanoparticles (Ab-CS-NPs) were spherical in shape, with an average particle size of 235.7 ± 10.2 nm and a zeta potential of 22.88 ± 1.78 mV. The therapeutic potential of the nanoparticles was evaluated based on their cellular uptake and gene silencing efficiency. Cellular accumulation and gene silencing efficiency of Ab-CS-NPs in astrocytes were significantly improved compared to non-modified CS-NPs and single-antibody-modified CS-NPs. These results suggest that the combination of anti-Tf antibody and anti-B2 antibody significantly increased the knockdown effect of siRNA-loaded nanoparticles. Thus, antibody-mediated dual-targeting nanoparticles are an efficient and promising delivery strategy for inhibiting HIV replication in astrocytes. Graphical abstract Graphic representation of dual-antibody-conjugated chitosan nanoparticles for the targeted delivery of siRNA across the blood-brain barrier (BBB) for inhibiting HIV replication in astrocytes. a Nanoparticle delivery to the BBB and penetration. b TfR-mediated

  2. Projecting human pharmacokinetics of therapeutic antibodies from nonclinical data: What have we learned?

    OpenAIRE

    Deng, Rong; Iyer, Suhasini; Theil, Frank-Peter; Mortensen, Deborah L; Fielder, Paul J; Prabhu, Saileta

    2011-01-01

    The pharmacokinetics (PK) of therapeutic antibodies is determined by target and non-target mediated mechanisms. These antibody-specific factors need to be considered during prediction of human PK based upon preclinical information. Principles of allometric scaling established for small molecules using data from multiple animal species cannot be directly applied to antibodies. Here, different methods for projecting human clearance (CL) from animal PK data for 13 therapeutic monoclonal antibodi...

  3. A natural human monoclonal antibody targeting Staphylococcus Protein A protects against Staphylococcus aureus bacteremia

    Science.gov (United States)

    Varshney, Avanish K.; Sunley, Kevin M.; Bowling, Rodney A.; Kwan, Tzu-Yu; Mays, Heather R.; Rambhadran, Anu; Zhang, Yanfeng; Martin, Rebecca L.; Cavalier, Michael C.; Simard, John

    2018-01-01

    Staphylococcus aureus can cause devastating and life-threatening infections. With the increase in multidrug resistant strains, novel therapies are needed. Limited success with active and passive immunization strategies have been attributed to S. aureus immune evasion. Here, we report on a monoclonal antibody, 514G3, that circumvents a key S. aureus evasion mechanism by targeting the cell wall moiety Protein A (SpA). SpA tightly binds most subclasses of immunoglobulins via their Fc region, neutralizing effector function. The organism can thus shield itself with a protective coat of serum antibodies and render humoral immunity ineffective. The present antibody reactivity was derived from an individual with natural anti-SpA antibody titers. The monoclonal antibody is of an IgG3 subclass, which differs critically from other immunoglobulin subclasses since its Fc is not bound by SpA. Moreover, it targets a unique epitope on SpA that allows it to bind in the presence of serum antibodies. Consequently, the antibody opsonizes S. aureus and maintains effector function to enable natural immune mediated clearance. The data presented here provide evidence that 514G3 antibody is able to successfully rescue mice from S. aureus mediated bacteremia. PMID:29364906

  4. Diclofenac hypersensitivity: antibody responses to the parent drug and relevant metabolites.

    Directory of Open Access Journals (Sweden)

    Andrea Harrer

    2010-10-01

    Full Text Available Hypersensitivity reactions against nonsteroidal antiinflammatory drugs (NSAIDs like diclofenac (DF can manifest as Type I-like allergic reactions including systemic anaphylaxis. However, except for isolated case studies experimental evidence for an IgE-mediated pathomechanism of DF hypersensitivity is lacking. In this study we aimed to investigate the possible involvement of drug- and/or metabolite-specific antibodies in selective DF hypersensitivity.DF, an organochemically synthesized linkage variant, and five major Phase I metabolites were covalently coupled to carrier proteins. Drug conjugates were analyzed for coupling degree and capacity to crosslink receptor-bound IgE antibodies from drug-sensitized mice. With these conjugates, the presence of hapten-specific IgE antibodies was investigated in patients' samples by ELISA, mediator release assay, and basophil activation test. Production of sulfidoleukotrienes by drug conjugates was determined in PBMCs from DF-hypersensitive patients. All conjugates were shown to carry more than two haptens per carrier molecule. Immunization of mice with drug conjugates induced drug-specific IgE antibodies capable of triggering mediator release. Therefore, the conjugates are suitable tools for detection of drug-specific antibodies and for determination of their anaphylactic activity. Fifty-nine patients were enrolled and categorized as hypersensitive either selectively to DF or to multiple NSAIDs. In none of the patients' samples evidence for drug/metabolite-specific IgE in serum or bound to allergic effector cells was found. In contrast, a small group of patients (8/59, 14% displayed drug/metabolite-specific IgG.We found no evidence for an IgE-mediated effector mechanism based on haptenation of protein carriers in DF-hypersensitive patients. Furthermore, a potential involvement of the most relevant metabolites in DF hypersensitivity reactions could be excluded.

  5. Antibody informatics for drug discovery

    DEFF Research Database (Denmark)

    Shirai, Hiroki; Prades, Catherine; Vita, Randi

    2014-01-01

    to the antibody science in every project in antibody drug discovery. Recent experimental technologies allow for the rapid generation of large-scale data on antibody sequences, affinity, potency, structures, and biological functions; this should accelerate drug discovery research. Therefore, a robust bioinformatic...... infrastructure for these large data sets has become necessary. In this article, we first identify and discuss the typical obstacles faced during the antibody drug discovery process. We then summarize the current status of three sub-fields of antibody informatics as follows: (i) recent progress in technologies...... for antibody rational design using computational approaches to affinity and stability improvement, as well as ab-initio and homology-based antibody modeling; (ii) resources for antibody sequences, structures, and immune epitopes and open drug discovery resources for development of antibody drugs; and (iii...

  6. Improvements in closeness, communication, and psychological distress mediate effects of couple therapy for veterans.

    Science.gov (United States)

    Doss, Brian D; Mitchell, Alexandra; Georgia, Emily J; Biesen, Judith N; Rowe, Lorelei Simpson

    2015-04-01

    Empirically based couple therapy results in significant improvements in relationship satisfaction for the average couple; however, further research is needed to identify mediators that lead to change and to ensure that improvements in mediators predict subsequent-not just concurrent-relationship satisfaction. In addition, given that much of the current literature on couple therapy examines outcomes in a research environment, it is important to examine mediators in a treatment-as-usual setting. To address these questions, 161 heterosexual couples (322 individuals) received treatment-as-usual couple therapy at one of two Veteran Administration Medical Centers (M = 5.0 and 13.0 sessions at the two sites) and were assessed before every session. The majority of couples were married (85%) and had been together for a median of 7.8 years (SD = 13). Participants were primarily White, non-Hispanic (69%), African American (21%), and White, Hispanic/Latino (8%). Individuals' own self-reported improvements in communication, emotional closeness, and psychological distress (but not frequency of behaviors targeted in treatment) mediated the effect of treatment on their subsequent relationship satisfaction. When all significant mediators were examined simultaneously, improvements in men's and women's emotional closeness and men's psychological distress independently mediated subsequent relationship satisfaction. In contrast, improvements in earlier relationship satisfaction mediated the effect of treatment only on subsequent psychological distress. This study identifies unique mediators of treatment effects and shows that gains in mechanisms predict subsequent relationship satisfaction. Future investigations should focus on the role of emotional closeness and psychological distress-constructs that have often been neglected-in couple therapy. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  7. Structure and function of broadly reactive antibody PG16 reveal an H3 subdomain that mediates potent neutralization of HIV-1

    Energy Technology Data Exchange (ETDEWEB)

    Pejchal, Robert; Walker, Laura M.; Stanfield, Robyn L.; Phogat, Sanjay K.; Koff, Wayne C.; Poignard, Pascal; Burton, Dennis R.; Wilson, Ian A. (Scripps); (IAVI)

    2010-11-15

    Development of an effective vaccine against HIV-1 will likely require elicitation of broad and potent neutralizing antibodies against the trimeric surface envelope glycoprotein (Env). Monoclonal antibodies (mAbs) PG9 and PG16 neutralize {approx}80% of HIV-1 isolates across all clades with extraordinary potency and target novel epitopes preferentially expressed on Env trimers. As these neutralization properties are ideal for a vaccine-elicited antibody response to HIV-1, their structural basis was investigated. The crystal structure of the antigen-binding fragment (Fab) of PG16 at 2.5 {angstrom} resolution revealed its unusually long, 28-residue, complementarity determining region (CDR) H3 forms a unique, stable subdomain that towers above the antibody surface. A 7-residue 'specificity loop' on the 'hammerhead' subdomain was identified that, when transplanted from PG16 to PG9 and vice versa, accounted for differences in the fine specificity and neutralization of these two mAbs. The PG16 electron density maps also revealed that a CDR H3 tyrosine was sulfated, which was confirmed for both PG9 (doubly) and PG16 (singly) by mass spectral analysis. We further showed that tyrosine sulfation plays a role in binding and neutralization. An N-linked glycan modification is observed in the variable light chain, but not required for antigen recognition. Further, the crystal structure of the PG9 light chain at 3.0 {angstrom} facilitated homology modeling to support the presence of these unusual features in PG9. Thus, PG9 and PG16 use unique structural features to mediate potent neutralization of HIV-1 that may be of utility in antibody engineering and for high-affinity recognition of a variety of therapeutic targets.

  8. Antibody-dependent enhancement of HIV-1 infection in human term syncytiotrophoblast cells cultured in vitro.

    Science.gov (United States)

    Tóth, F D; Mosborg-Petersen, P; Kiss, J; Aboagye-Mathiesen, G; Zdravkovic, M; Hager, H; Aranyosi, J; Lampé, L; Ebbesen, P

    1994-06-01

    We examined if Fc receptor-mediated antibody-dependent enhancement (FcR-ADE) or complement-mediated antibody-dependent enhancement (C'-ADE) of virus infection can contribute to increasing replication of HIV-1 in human syncytiotrophoblast (ST) cells. Here we report that both FcR-ADE and C'-ADE may result in enhanced virus release from HIV-1-infected ST cells. We show that FcR-ADE of HIV-1 infection in ST cells is mediated by FcRIII and other FcR(s) belonging to undetermined Fc classes and does not require CD4 receptors, whereas C'-ADE uses both CD4 and CR2-like receptors. FcR-ADE seems to be more efficient in enhancing HIV-1 replication than C'-ADE. While FcR-ADE leads to increased internalization of HIV-1, C'-ADE does not result in enhanced endocytosis of the virus. In addition, antibodies mediating FcR-ADE are reactive with the gp120 viral envelope antigen, whereas antibodies involved in C'-ADE react with the viral transmembrane glycoprotein gp41. Data suggest that both FcR-ADE and C'-ADE may contribute to the spread of HIV-1 from mother to the fetus.

  9. Treatment of immune-mediated temporal lobe epilepsy with GAD antibodies.

    Science.gov (United States)

    Malter, M P; Frisch, C; Zeitler, H; Surges, R; Urbach, H; Helmstaedter, C; Elger, C E; Bien, C G

    2015-08-01

    Temporal lobe epilepsy with antibodies (abs) against the glutamic acid decarboxylase 65 isoform (GAD-TLE) is known as an immune-mediated neurological syndrome. Here we evaluate the therapy response to various immunotherapies and epilepsy surgery in this syndrome. All patients with GAD-TLE and follow-up data and stored serum and CSF samples, identified and treated at the Bonn centre from 2002 to 2010, were studied retrospectively. Seizure freedom for ≥1 year and reduction of ≥50%, i.e. therapy response, were assessed. GAD-ab titres and neuropsychological performances were documented prior and after individual interventions. Thirteen patients with GAD-TLE were identified with the following seizure responses: corticosteroids (5 responders out of 11 treated patients); i.v. immunoglobulins (1/5), apheresis therapy (1/8); and natalizumab (1/1), selective amygdala-hippocampectomy (2/3). None of the patients achieved sustained seizure freedom apart from one patient. This patient was on antiepileptic drug treatment after discontinuation of immunotherapy. The seizure response to immunotherapies in patients with GAD-TLE was poor. Corticosteroids were the most effective regarding seizure response. Especially the poor effects of apheresis therapies support the idea that GAD-abs are not directly pathogenic. None of three patients was seizure-free after temporal lobe surgery suggesting that GAD-TLE patients respond worse than others to this type of intervention. Our results reflect the chronic course of the disease with low likelihood for patients with GAD-TLE to attain long-term seizure freedom. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  10. Antibody or Antibody Fragments: Implications for Molecular Imaging and Targeted Therapy of Solid Tumors

    Directory of Open Access Journals (Sweden)

    Katerina T. Xenaki

    2017-10-01

    Full Text Available The use of antibody-based therapeutics has proven very promising for clinical applications in cancer patients, with multiple examples of antibodies and antibody–drug conjugates successfully applied for the treatment of solid tumors and lymphomas. Given reported recurrence rates, improvements are clearly still necessary. A major factor limiting the efficacy of antibody-targeted cancer therapies may be the incomplete penetration of the antibody or antibody–drug conjugate into the tumor. Incomplete tumor penetration also affects the outcome of molecular imaging, when using such targeting agents. From the injection site until they arrive inside the tumor, targeting molecules are faced with several barriers that impact intratumoral distribution. The primary means of antibody transport inside tumors is based on diffusion. The diffusive penetration inside the tumor is influenced by both antibody properties, such as size and binding affinity, as well as tumor properties, such as microenvironment, vascularization, and targeted antigen availability. Engineering smaller antibody fragments has shown to improve the rate of tumor uptake and intratumoral distribution. However, it is often accompanied by more rapid clearance from the body and in several cases also by inherent destabilization and reduction of the binding affinity of the antibody. In this perspective, we discuss different cancer targeting approaches based on antibodies or their fragments. We carefully consider how their size and binding properties influence their intratumoral uptake and distribution, and how this may affect cancer imaging and therapy of solid tumors.

  11. Complement-Mediated Enhancement of Monocyte Adhesion to Endothelial Cells by HLA Antibodies, and Blockade by a Specific Inhibitor of the Classical Complement Cascade, TNT003

    Science.gov (United States)

    Valenzuela, Nicole M.; Thomas, Kimberly A.; Mulder, Arend; Parry, Graham C.; Panicker, Sandip; Reed, Elaine F.

    2017-01-01

    Background Antibody-mediated rejection (AMR) of most solid organs is characterized by evidence of complement activation and/or intragraft macrophages (C4d + and CD68+ biopsies). We previously demonstrated that crosslinking of HLA I by antibodies triggered endothelial activation and monocyte adhesion. We hypothesized that activation of the classical complement pathway at the endothelial cell surface by HLA antibodies would enhance monocyte adhesion through soluble split product generation, in parallel with direct endothelial activation downstream of HLA signaling. Methods Primary human aortic endothelial cells (HAEC) were stimulated with HLA class I antibodies in the presence of intact human serum complement. C3a and C5a generation, endothelial P-selectin expression, and adhesion of human primary and immortalized monocytes (Mono Mac 6) were measured. Alternatively, HAEC or monocytes were directly stimulated with purified C3a or C5a. Classical complement activation was inhibited by pretreatment of complement with an anti-C1s antibody (TNT003). Results Treatment of HAEC with HLA antibody and human complement increased the formation of C3a and C5a. Monocyte recruitment by human HLA antibodies was enhanced in the presence of intact human serum complement or purified C3a or C5a. Specific inhibition of the classical complement pathway using TNT003 or C1q-depleted serum significantly reduced adhesion of monocytes in the presence of human complement. Conclusions Despite persistent endothelial viability in the presence of HLA antibodies and complement, upstream complement anaphylatoxin production exacerbates endothelial exocytosis and leukocyte recruitment. Upstream inhibition of classical complement may be therapeutic to dampen mononuclear cell recruitment and endothelial activation characteristic of microvascular inflammation during AMR. PMID:28640789

  12. Charge-mediated Fab-Fc interactions in an IgG1 antibody induce reversible self-association, cluster formation, and elevated viscosity.

    Science.gov (United States)

    Arora, Jayant; Hu, Yue; Esfandiary, Reza; Sathish, Hasige A; Bishop, Steven M; Joshi, Sangeeta B; Middaugh, C Russell; Volkin, David B; Weis, David D

    Concentration-dependent reversible self-association (RSA) of monoclonal antibodies (mAbs) poses a challenge to their pharmaceutical development as viable candidates for subcutaneous delivery. While the role of the antigen-binding fragment (Fab) in initiating RSA is well-established, little evidence supports the involvement of the crystallizable fragment (Fc). In this report, a variety of biophysical tools, including hydrogen exchange mass spectrometry, are used to elucidate the protein interface of such non-covalent protein-protein interactions. Using dynamic and static light scattering combined with viscosity measurements, we find that an IgG1 mAb (mAb-J) undergoes RSA primarily through electrostatic interactions and forms a monomer-dimer-tetramer equilibrium. We provide the first direct experimental mapping of the interface formed between the Fab and Fc domains of an antibody at high protein concentrations. Charge distribution heterogeneity between the positively charged interface spanning complementarity-determining regions CDR3H and CDR2L in the Fab and a negatively charged region in C H 3/Fc domain mediates the RSA of mAb-J. When arginine and NaCl are added, they disrupt RSA of mAb-J and decrease the solution viscosity. Fab-Fc domain interactions between mAb monomers may promote the formation of large transient antibody complexes that ultimately cause increases in solution viscosity. Our findings illustrate how limited specific arrangements of amino-acid residues can cause mAbs to undergo RSA at high protein concentrations and how conserved regions in the Fc portion of the antibody can also play an important role in initiating weak and transient protein-protein interactions.

  13. Cytosolic antibody delivery by lipid-sensitive endosomolytic peptide

    Science.gov (United States)

    Akishiba, Misao; Takeuchi, Toshihide; Kawaguchi, Yoshimasa; Sakamoto, Kentarou; Yu, Hao-Hsin; Nakase, Ikuhiko; Takatani-Nakase, Tomoka; Madani, Fatemeh; Gräslund, Astrid; Futaki, Shiroh

    2017-08-01

    One of the major obstacles in intracellular targeting using antibodies is their limited release from endosomes into the cytosol. Here we report an approach to deliver proteins, which include antibodies, into cells by using endosomolytic peptides derived from the cationic and membrane-lytic spider venom peptide M-lycotoxin. The delivery peptides were developed by introducing one or two glutamic acid residues into the hydrophobic face. One peptide with the substitution of leucine by glutamic acid (L17E) was shown to enable a marked cytosolic liberation of antibodies (immunoglobulins G (IgGs)) from endosomes. The predominant membrane-perturbation mechanism of this peptide is the preferential disruption of negatively charged membranes (endosomal membranes) over neutral membranes (plasma membranes), and the endosomolytic peptide promotes the uptake by inducing macropinocytosis. The fidelity of this approach was confirmed through the intracellular delivery of a ribosome-inactivation protein (saporin), Cre recombinase and IgG delivery, which resulted in a specific labelling of the cytosolic proteins and subsequent suppression of the glucocorticoid receptor-mediated transcription. We also demonstrate the L17E-mediated cytosolic delivery of exosome-encapsulated proteins.

  14. P. falciparum infection and maternofetal antibody transfer in malaria-endemic settings of varying transmission.

    Directory of Open Access Journals (Sweden)

    Alistair R D McLean

    Full Text Available During pregnancy, immunoglobulin G (IgG is transferred from the mother to the fetus, providing protection from disease in early infancy. Plasmodium falciparum infections may reduce maternofetal antibody transfer efficiency, but mechanisms remain unclear.Mother-cord paired serum samples collected at delivery from Papua New Guinea (PNG and the Thailand-Myanmar Border Area (TMBA were tested for IgG1 and IgG3 to four P. falciparum antigens and measles antigen, as well as total serum IgG. Multivariable linear regression was conducted to assess the association of peripheral P. falciparum infection during pregnancy or placental P. falciparum infection assessed at delivery with maternofetal antibody transfer efficiency. Path analysis assessed the extent to which associations between P. falciparum infection and antibody transfer were mediated by gestational age at delivery or levels of maternal total serum IgG.Maternofetal antibody transfer efficiency of IgG1 and IgG3 was lower in PNG compared to TMBA (mean difference in cord antibody levels (controlling for maternal antibody levels ranged from -0.88 to 0.09, median of -0.20 log2 units. Placental P. falciparum infections were associated with substantially lower maternofetal antibody transfer efficiency in PNG primigravid women (mean difference in cord antibody levels (controlling for maternal antibody levels ranged from -0.62 to -0.10, median of -0.36 log2 units, but not multigravid women. The lower antibody transfer efficiency amongst primigravid women with placental infection was only partially mediated by gestational age at delivery (proportion indirect effect ranged from 0% to 18%, whereas no mediation effects of maternal total serum IgG were observed.Primigravid women may be at risk of impaired maternofetal antibody transport with placental P. falciparum infection. Direct effects of P. falciparum on the placenta, rather than earlier gestational age and elevated serum IgG, are likely responsible for

  15. Antibody dependent cellular phagocytosis by macrophages is a novel mechanism of action of elotuzumab.

    Science.gov (United States)

    Kurdi, Ahmed T; Glavey, Siobhan V; Bezman, Natalie A; Jhatakia, Amy; Guerriero, Jennifer L; Manier, Salomon; Moschetta, Michele; Mishima, Yuji; Roccaro, Aldo; Detappe, Alexandre; Liu, Chia-Jen; Sacco, Antonio; Huynh, Daisy; Tai, Yu-Tzu; Robbins, Michael D; Azzi, Jamil; Ghobrial, Irene M

    2018-04-13

    Elotuzumab, a recently approved antibody for the treatment of multiple myeloma (MM), has been shown to stimulate Fcγ receptor (FcγR)-mediated antibody-dependent cellular cytotoxicity (ADCC) by natural killer (NK) cells towards myeloma cells. The modulatory effects of elotuzumab on other effector cells in the tumor microenvironment, however, has not been fully explored. Antibody dependent cellular phagocytosis (ADCP) is a mechanism by which macrophages contribute to anti-tumor potency of monoclonal antibodies. Herein, we studied the NK cell independent effect of elotuzumab on tumor associated macrophages (TAMs) using a xenograft tumor model deficient in NK and adaptive immune cells. We demonstrate significant anti-tumor efficacy of single agent elotuzumab in immunocompromised xenograft models of multiple myeloma, which is in part mediated by Fc-FcγR interaction of elotuzumab with macrophages. Elotuzumab is shown in this study to induce phenotypic activation of macrophages in-vivo and mediates ADCP of myeloma cells though a FcγR dependent manner in-vitro. Together, these findings propose a novel immune mediated mechanism by which elotuzumab exerts anti-myeloma activity and helps to provide rationale for combination therapies that can enhance macrophage activity. Copyright ©2018, American Association for Cancer Research.

  16. Fatal Pneumococcus Sepsis after Treatment of Late Antibody-Mediated Kidney Graft Rejection

    Directory of Open Access Journals (Sweden)

    Gunilla Einecke

    2018-01-01

    Full Text Available Antibody-mediated rejection (ABMR is a major cause of late renal allograft dysfunction and graft loss. Risks and benefits of treatment of late ABMR have not been evaluated in randomized clinical trials. We report on a 35-year-old patient with deterioration in renal function and progressive proteinuria 15 years after transplantation. Recurrent infections after a splenectomy following traumatic splenic rupture 3 years earlier had led to reduction of immunosuppression. Renal transplant biopsy showed glomerular double contours, 40% fibrosis/tubular atrophy, peritubular capillaritis, and positive C4d staining indicating chronic-active ABMR. ABMR treatment was initiated with steroids, plasmapheresis, and rituximab. Fourteen days later, she presented to the emergency department with fever, diarrhea, vomiting, and hypotension. Despite antibiotic treatment she deteriorated with progressive hypotension, capillary leak with pleural effusion, peripheral edema, and progressive respiratory insufficiency. She died due to septic shock five days after admission. Blood cultures showed Streptococcus pneumoniae, consistent with a diagnosis of overwhelming postsplenectomy infection syndrome, despite protective pneumococcus vaccination titers. We assume that the infection was caused by one of the strains not covered by the Pneumovax 23 vaccination. The increased immunosuppression with B cell depletion may have contributed to the overwhelming course of this infection.

  17. Development of antibody-based c-Met inhibitors for targeted cancer therapy

    Directory of Open Access Journals (Sweden)

    Lee D

    2015-02-01

    Full Text Available Dongheon Lee, Eun-Sil Sung, Jin-Hyung Ahn, Sungwon An, Jiwon Huh, Weon-Kyoo You Hanwha Chemical R&D Center, Biologics Business Unit, Daejeon, Republic of Korea Abstract: Signaling pathways mediated by receptor tyrosine kinases (RTKs and their ligands play important roles in the development and progression of human cancers, which makes RTK-mediated signaling pathways promising therapeutic targets in the treatment of cancer. Compared with small-molecule compounds, antibody-based therapeutics can more specifically recognize and bind to ligands and RTKs. Several antibody inhibitors of RTK-mediated signaling pathways, such as human epidermal growth factor receptor 2, vascular endothelial growth factor, epidermal growth factor receptor or vascular endothelial growth factor receptor 2, have been developed and are widely used to treat cancer patients. However, since the therapeutic options are still limited in terms of therapeutic efficacy and types of cancers that can be treated, efforts are being made to identify and evaluate novel RTK-mediated signaling pathways as targets for more efficacious cancer treatment. The hepatocyte growth factor/c-Met signaling pathway has come into the spotlight as a promising target for development of potent cancer therapeutic agents. Multiple antibody-based therapeutics targeting hepatocyte growth factor or c-Met are currently in preclinical or clinical development. This review focuses on the development of inhibitors of the hepatocyte growth factor/c-Met signaling pathway for cancer treatment, including critical issues in clinical development and future perspectives for antibody-based therapeutics. Keywords: hepatocyte growth factor, ligands, receptor tyrosine kinase, signaling pathway, therapeutic agent

  18. Anti-NMDA-receptor encephalitis: case series and analysis of the effects of antibodies.

    Science.gov (United States)

    Dalmau, Josep; Gleichman, Amy J; Hughes, Ethan G; Rossi, Jeffrey E; Peng, Xiaoyu; Lai, Meizan; Dessain, Scott K; Rosenfeld, Myrna R; Balice-Gordon, Rita; Lynch, David R

    2008-12-01

    A severe form of encephalitis associated with antibodies against NR1-NR2 heteromers of the NMDA receptor was recently identified. We aimed to analyse the clinical and immunological features of patients with the disorder and examine the effects of antibodies against NMDA receptors in neuronal cultures. We describe the clinical characteristics of 100 patients with encephalitis and NR1-NR2 antibodies. HEK293 cells ectopically expressing single or assembled NR1-NR2 subunits were used to determine the epitope targeted by the antibodies. Antibody titres were measured with ELISA. The effect of antibodies on neuronal cultures was determined by quantitative analysis of NMDA-receptor clusters. Median age of patients was 23 years (range 5-76 years); 91 were women. All patients presented with psychiatric symptoms or memory problems; 76 had seizures, 88 unresponsiveness (decreased consciousness), 86 dyskinesias, 69 autonomic instability, and 66 hypoventilation. 58 (59%) of 98 patients for whom results of oncological assessments were available had tumours, most commonly ovarian teratoma. Patients who received early tumour treatment (usually with immunotherapy) had better outcome (p=0.004) and fewer neurological relapses (p=0.009) than the rest of the patients. 75 patients recovered or had mild deficits and 25 had severe deficits or died. Improvement was associated with a decrease of serum antibody titres. The main epitope targeted by the antibodies is in the extracellular N-terminal domain of the NR1 subunit. Patients' antibodies decreased the numbers of cell-surface NMDA receptors and NMDA-receptor clusters in postsynaptic dendrites, an effect that could be reversed by antibody removal. A well-defined set of clinical characteristics are associated with anti-NMDA-receptor encephalitis. The pathogenesis of the disorder seems to be mediated by antibodies.

  19. Improved porous silicon (P-Si) microarray based PSA (prostate specific antigen) immunoassay by optimized surface density of the capture antibody

    Science.gov (United States)

    Lee, SangWook; Kim, Soyoun; Malm, Johan; Jeong, Ok Chan; Lilja, Hans; Laurell, Thomas

    2014-01-01

    Enriching the surface density of immobilized capture antibodies enhances the detection signal of antibody sandwich microarrays. In this study, we improved the detection sensitivity of our previously developed P-Si (porous silicon) antibody microarray by optimizing concentrations of the capturing antibody. We investigated immunoassays using a P-Si microarray at three different capture antibody (PSA - prostate specific antigen) concentrations, analyzing the influence of the antibody density on the assay detection sensitivity. The LOD (limit of detection) for PSA was 2.5ngmL−1, 80pgmL−1, and 800fgmL−1 when arraying the PSA antibody, H117 at the concentration 15µgmL−1, 35µgmL−1 and 154µgmL−1, respectively. We further investigated PSA spiked into human female serum in the range of 800fgmL−1 to 500ngmL−1. The microarray showed a LOD of 800fgmL−1 and a dynamic range of 800 fgmL−1 to 80ngmL−1 in serum spiked samples. PMID:24016590

  20. Monoclonal antibody therapy of inflammatory bowel disease

    NARCIS (Netherlands)

    van Deventer, S. J.; Camoglio, L.

    1997-01-01

    Animal models of inflammatory bowel disease have provided insight in the regulation of mucosal inflammation. This has resulted in novel therapeutic approaches that specifically target a single inflammatory mediator. Monoclonal antibody therapy has been used in steroid refractory Crohn's disease

  1. Antibody-mediated immunity to the obligate intracellular bacterial pathogen Coxiella burnetii is Fc receptor- and complement-independent

    Directory of Open Access Journals (Sweden)

    Heinzen Robert A

    2009-05-01

    Full Text Available Abstract Background The obligate intracellular bacterial pathogen Coxiella burnetii causes the zoonosis Q fever. The intracellular niche of C. burnetii has led to the assumption that cell-mediated immunity is the most important immune component for protection against this pathogen. However, passive immunization with immune serum can protect naïve animals from challenge with virulent C. burnetii, indicating a role for antibody (Ab in protection. The mechanism of this Ab-mediated protection is unknown. Therefore, we conducted a study to determine whether Fc receptors (FcR or complement contribute to Ab-mediated immunity (AMI to C. burnetii. Results Virulent C. burnetii infects and replicates within human dendritic cells (DC without inducing their maturation or activation. We investigated the effects of Ab opsonized C. burnetii on human monocyte-derived and murine bone marrow-derived DC. Infection of DC with Ab-opsonized C. burnetii resulted in increased expression of maturation markers and inflammatory cytokine production. Bacteria that had been incubated with naïve serum had minimal effect on DC, similar to virulent C. burnetii alone. The effect of Ab opsonized C. burnetii on DC was FcR dependent as evidenced by a reduced response of DC from FcR knockout (FcR k/o compared to C57Bl/6 (B6 mice. To address the potential role of FcR in Ab-mediated protection in vivo, we compared the response of passively immunized FcR k/o mice to the B6 controls. Interestingly, we found that FcR are not essential for AMI to C. burnetii in vivo. We subsequently examined the role of complement in AMI by passively immunizing and challenging several different strains of complement-deficient mice and found that AMI to C. burnetii is also complement-independent. Conclusion Despite our data showing FcR-dependent stimulation of DC in vitro, Ab-mediated immunity to C. burnetii in vivo is FcR-independent. We also found that passive immunity to this pathogen is independent of

  2. Application of cyclodextrins in antibody microparticles: potentials for antibody protection in spray drying.

    Science.gov (United States)

    Ramezani, Vahid; Vatanara, Alireza; Seyedabadi, Mohammad; Nabi Meibodi, Mohsen; Fanaei, Hamed

    2017-07-01

    Dry powder formulations are extensively used to improve the stability of antibodies. Spray drying is one of important methods for protein drying. This study investigated the effects of trehalose, hydroxypropyl beta cyclodextrin (HPBCD) and beta cyclodextrin (BCD) on the stability and particle properties of spray-dried IgG. D-optimal design was employed for both experimental design and analysis and optimization of the variables. The size and aerodynamic behavior of particles were determined using laser light scattering and glass twin impinger, respectively. In addition, stability, ratio of beta sheets and morphology of antibody were analyzed using size exclusion chromatography, IR spectroscopy and electron microscopy, respectively. Particle properties and antibody stability were significantly improved in the presence of HPBCD. In addition, particle aerodynamic behavior, in terms of fine-particle fraction (FPF), enhanced up to 52.23%. Furthermore, antibody was better preserved not only during spray drying, but also during long-term storage. In contrast, application of BCD resulted in the formation of larger particles. Although trehalose caused inappropriate aerodynamic property, it efficiently decreased antibody aggregation. HPBCD is an efficient excipient for the development of inhalable protein formulations. In this regard, optimal particle property and antibody stability was obtained with proper combination of cyclodextrins and simple sugars, such as trehalose.

  3. Identification of antigen-specific human monoclonal antibodies using high-throughput sequencing of the antibody repertoire.

    Science.gov (United States)

    Liu, Ju; Li, Ruihua; Liu, Kun; Li, Liangliang; Zai, Xiaodong; Chi, Xiangyang; Fu, Ling; Xu, Junjie; Chen, Wei

    2016-04-22

    High-throughput sequencing of the antibody repertoire provides a large number of antibody variable region sequences that can be used to generate human monoclonal antibodies. However, current screening methods for identifying antigen-specific antibodies are inefficient. In the present study, we developed an antibody clone screening strategy based on clone dynamics and relative frequency, and used it to identify antigen-specific human monoclonal antibodies. Enzyme-linked immunosorbent assay showed that at least 52% of putative positive immunoglobulin heavy chains composed antigen-specific antibodies. Combining information on dynamics and relative frequency improved identification of positive clones and elimination of negative clones. and increase the credibility of putative positive clones. Therefore the screening strategy could simplify the subsequent experimental screening and may facilitate the generation of antigen-specific antibodies. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Analysis of anti-HLA antibodies in sensitized kidney transplant candidates subjected to desensitization with intravenous immunoglobulin and rituximab.

    Science.gov (United States)

    Lobashevsky, Andrew L; Higgins, Nancy G; Rosner, Kevin M; Mujtaba, Muhammad A; Goggins, William C; Taber, Tim E

    2013-07-27

    Preexisting donor-specific antibodies against human leukocyte antigens are major risk factors for acute antibody-mediated and chronic rejection of kidney transplant grafts. Immunomodulation (desensitization) protocols may reduce antibody concentration and improve the success of transplant. We investigated the effect of desensitization with intravenous immunoglobulin and rituximab on the antibody profile in highly sensitized kidney transplant candidates. In 31 transplant candidates (calculated panel-reactive antibody [cPRA], 34%-99%), desensitization included intravenous immunoglobulin on days 0 and 30 and a single dose of rituximab on day 15. Anti-human leukocyte antigen antibodies were analyzed before and after desensitization. Reduction of cPRA from 25% to 50% was noted for anti-class I (5 patients, within 20-60 days) and anti-class II (3 patients, within 10-20 days) antibodies. After initial reduction of cPRA, the cPRA increased within 120 days. In 24 patients, decrease in mean fluorescence intensity of antibodies by more than 50% was noted at follow-up, but there was no reduction of cPRA. Rebound occurred in 65% patients for anti-class I antibodies at 350 days and anti-class II antibodies at 101 to 200 days. Probability of rebound effect was higher in patients with mean fluorescence intensity of more than 10,700 before desensitization, anti-class II antibodies, and history of previous transplant. The desensitization protocol had limited efficacy in highly sensitized kidney transplant candidate because of the short period with antibody reduction and high frequency of rebound effect.

  5. Antibody-dependent cellular cytotoxicity and skin disease

    International Nuclear Information System (INIS)

    Norris, D.A.; Lee, L.A.

    1985-01-01

    Antibody dependent cellular cytotoxicity (ADCC) is a recently described mechanism of immunologic lysis in which cellular targets sensitized by specific antibodies are efficiently and selectively lysed by Fc receptor (FcR) bearing nonspecific effectors. Immunoglobulins of various classes (IgG, IgM, IgA, IgE) and various cellular effectors (large granular lymphocytes, monocyte/macrophages, T lymphocytes, neutrophils, and eosinophils) can induce ADCC in vitro, and the importance of ADCC in vivo is being tested experimentally in resistance to viral, bacterial, and parasitic infection, in tumor surveillance, in allograft rejection, and in inflammatory diseases. There is much indirect evidence that ADCC may be the mechanism of damage of different cellular targets in skin diseases, but the best direct evidence concerns immunologic keratinocyte damage, especially in cutaneous lupus erythematosus (LE). The authors have shown that keratinocytes of several species are highly susceptible to lymphocyte and monocyte-mediated ADCC, but not to neutrophil or eosinophil ADCC in vitro using two different cytotoxicity assays. In contrast, complement was a relatively ineffective mediator of lysis of metabolically intact keratinocyte targets. Patients with certain cutaneous lupus syndromes have serum antibodies capable of inducing monocyte and lymphocyte ADCC of targets coated with extractable nuclear antigens. The authors have shown that these antigens apparently move to the cell membrane of keratinocytes in vitro following ultraviolet irradiation. In an animal model, they have shown that antibodies to SSA/Ro bind to human keratinocytes in vivo, especially after ultraviolet irradiation

  6. MP-4 Contributes to Snake Venom Neutralization by Mucuna pruriens Seeds through an Indirect Antibody-mediated Mechanism.

    Science.gov (United States)

    Kumar, Ashish; Gupta, Chitra; Nair, Deepak T; Salunke, Dinakar M

    2016-05-20

    Mortality due to snakebite is a serious public health problem, and available therapeutics are known to induce debilitating side effects. Traditional medicine suggests that seeds of Mucuna pruriens can provide protection against the effects of snakebite. Our aim is to identify the protein(s) that may be important for snake venom neutralization and elucidate its mechanism of action. To this end, we have identified and purified a protein from M. pruriens, which we have named MP-4. The full-length polypeptide sequence of MP-4 was obtained through N-terminal sequencing of peptide fragments. Sequence analysis suggested that the protein may belong to the Kunitz-type protease inhibitor family and therefore may potentially neutralize the proteases present in snake venom. Using various structural and biochemical tools coupled with in vivo assays, we are able to show that MP-4 does not afford direct protection against snake venom because it is actually a poor inhibitor of serine proteases. Further experiments showed that antibodies generated against MP-4 cross-react with the whole venom and provide protection to mice against Echis carinatus snake venom. This study shows that the MP-4 contributes significantly to the snake venom neutralization activity of M. pruriens seeds through an indirect antibody-mediated mechanism. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Focal CA3 hippocampal subfield atrophy following LGI1 VGKC-complex antibody limbic encephalitis.

    Science.gov (United States)

    Miller, Thomas D; Chong, Trevor T-J; Aimola Davies, Anne M; Ng, Tammy W C; Johnson, Michael R; Irani, Sarosh R; Vincent, Angela; Husain, Masud; Jacob, Saiju; Maddison, Paul; Kennard, Christopher; Gowland, Penny A; Rosenthal, Clive R

    2017-05-01

    Magnetic resonance imaging has linked chronic voltage-gated potassium channel (VGKC) complex antibody-mediated limbic encephalitis with generalized hippocampal atrophy. However, autoantibodies bind to specific rodent hippocampal subfields. Here, human hippocampal subfield (subiculum, cornu ammonis 1-3, and dentate gyrus) targets of immunomodulation-treated LGI1 VGKC-complex antibody-mediated limbic encephalitis were investigated using in vivo ultra-high resolution (0.39 × 0.39 × 1.0 mm3) 7.0 T magnetic resonance imaging [n = 18 patients, 17 patients (94%) positive for LGI1 antibody and one patient negative for LGI1/CASPR2 but positive for VGKC-complex antibodies, mean age: 64.0 ± 2.55 years, median 4 years post-limbic encephalitis onset; n = 18 controls]. First, hippocampal subfield quantitative morphometry indicated significant volume loss confined to bilateral CA3 [F(1,34) = 16.87, P 3 months from symptom onset) were associated with CA3 atrophy. Third, whole-brain voxel-by-voxel morphometry revealed no significant grey matter loss. Fourth, CA3 subfield atrophy was associated with severe episodic but not semantic amnesia for postmorbid autobiographical events that was predicted by variability in CA3 volume. The results raise important questions about the links with histopathology, the impact of the observed focal atrophy on other CA3-mediated reconstructive and episodic mechanisms, and the role of potential antibody-mediated pathogenicity as part of the pathophysiology cascade in humans. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain.

  8. An Fc engineering approach that modulates antibody-dependent cytokine release without altering cell-killing functions.

    Science.gov (United States)

    Kinder, Michelle; Greenplate, Allison R; Strohl, William R; Jordan, Robert E; Brezski, Randall J

    2015-01-01

    Cytotoxic therapeutic monoclonal antibodies (mAbs) often mediate target cell-killing by eliciting immune effector functions via Fc region interactions with cellular and humoral components of the immune system. Key functions include antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and complement-dependent cytotoxicity (CDC). However, there has been increased appreciation that along with cell-killing functions, the induction of antibody-dependent cytokine release (ADCR) can also influence disease microenvironments and therapeutic outcomes. Historically, most Fc engineering approaches have been aimed toward modulating ADCC, ADCP, or CDC. In the present study, we describe an Fc engineering approach that, while not resulting in impaired ADCC or ADCP, profoundly affects ADCR. As such, when peripheral blood mononuclear cells are used as effector cells against mAb-opsonized tumor cells, the described mAb variants elicit a similar profile and quantity of cytokines as IgG1. In contrast, although the variants elicit similar levels of tumor cell-killing as IgG1 with macrophage effector cells, the variants do not elicit macrophage-mediated ADCR against mAb-opsonized tumor cells. This study demonstrates that Fc engineering approaches can be employed to uncouple macrophage-mediated phagocytic and subsequent cell-killing functions from cytokine release.

  9. Radioimmunoassay for quantification of anti-tuberculin antibody concentration in guinea pig sera

    Energy Technology Data Exchange (ETDEWEB)

    Mauch, H [Universitaet des Saarlandes, Homburg/Saar (Germany, F.R.). Medizinische Klinik und Poliklinik; Kuemel, G [Universitaet des Saarlandes, Homburg/Saar (Germany, F.R.). Virologische Abt.

    1978-04-01

    A well suited model system for the study of the role of antibodies in immunoregulation is the BCG-infected guinea pig. The assessment of a detailed analysis of the antibody kinetics after BCG infection in comparison to the kinetics of cell-mediated immunity by the delayed type hypersensitivity reaction requires that a specially sensitive, reproducible and precise assay for the determination of antibody concentration is at hand. The methods hitherto available do not meet these requirements. There was developed an indirect double antibody solid phase radioimmunoassay for that purpose.

  10. Superficial Dsg2 Expression Limits Epidermal Blister Formation Mediated by Pemphigus Foliaceus Antibodies and Exfoliative Toxins

    Directory of Open Access Journals (Sweden)

    Donna Brennan

    2010-01-01

    Full Text Available Cell-cell adhesion mediated by desmosomes is crucial for maintaining proper epidermal structure and function, as evidenced by several severe and potentially fatal skin disorders involving impairment of desmosomal proteins. Pemphigus foliaceus (PF and staphylococcal scalded skin syndrome (SSSS are subcorneal blistering diseases resulting from loss of function of the desmosomal cadherin, desmoglein 1 (Dsg1. To further study the pathomechanism of these diseases and to assess the adhesive properties of Dsg2, we employed a recently established transgenic (Tg mouse model expressing Dsg2 in the superficial epidermis. Neonatal Tg and wild type (WT mice were injected with purified ETA or PF Ig. We showed that ectopic expression of Dsg2 reduced the extent of blister formation in response to both ETA and PF Ig. In response to PF Ig, we observed either a dramatic loss or a reorganization of Dsg1-α, Dsg1-β, and, to a lesser extent, Dsg1-γ, in WT mice. The Inv-Dsg2 Tg mice showed enhanced retention of Dsg1 at the cell-cell border. Collectively, our data support the role for Dsg2 in cell adhesion and suggest that ectopic superficial expression of Dsg2 can increase membrane preservation of Dsg1 and limit epidermal blister formation mediated by PF antibodies and exfoliative toxins.

  11. The perfect storm: HLA antibodies, complement, FcγRs, and endothelium in transplant rejection.

    Science.gov (United States)

    Thomas, Kimberly A; Valenzuela, Nicole M; Reed, Elaine F

    2015-05-01

    The pathophysiology of antibody-mediated rejection (AMR) in solid organ transplants is multifaceted and predominantly caused by antibodies directed against polymorphic donor human leukocyte antigens (HLAs). Despite the clearly detrimental impact of HLA antibodies (HLA-Abs) on graft function and survival, the prevention, diagnosis, and treatment of AMR remain a challenge. The histological manifestations of AMR reflect the signatures of HLA-Ab-triggered injury, specifically endothelial changes, recipient leukocytic infiltrate, and complement deposition. We review the interconnected mechanisms of HLA-Ab-mediated injury that might synergize in a 'perfect storm' of inflammation. Characterization of antibody features that are critical for effector functions may help to identify HLA-Abs that are more likely to cause rejection. We also highlight recent advances that may pave the way for new, more effective therapies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Monoclonal antibodies and cancer

    International Nuclear Information System (INIS)

    Haisma, H.J.

    1987-01-01

    The usefulness of radiolabeled monoclonal antibodies for imaging and treatment of human (ovarian) cancer was investigated. A review of tumor imaging with monoclonal antibodies is presented. Special attention is given to factors that influence the localization of the antibodies in tumors, isotope choice and methods of radiolabeling of the monoclonal antibodies. Two monoclonal antibodies, OC125 and OV-TL3, with high specificity for human epithelial ovarian cancer are characterized. A simple radio-iodination technique was developed for clinical application of the monoclonal antibodies. The behavior of monoclonal antibodies in human tumor xenograft systems and in man are described. Imaging of tumors is complicated because of high background levels of radioactivity in other sites than the tumor, especially in the bloodpool. A technique was developed to improve imaging of human tumor xenographs in nude mice, using subtraction of a specific and a non-specific antibody, radiolabeled with 111 In, 67 Ga and 131 I. To investigate the capability of the two monoclonal antibodies, to specifically localize in human ovarian carcinomas, distribution studies in mice bearing human ovarian carcinoma xenografts were performed. One of the antibodies, OC125, was used for distribution studies in ovarian cancer patients. OC125 was used because of availability and approval to use this antibody in patients. The same antibody was used to investigate the usefulness of radioimmunoimaging in ovarian cancer patients. The interaction of injected radiolabeled antibody OC125 with circulating antigen and an assay to measure the antibody response in ovarian cancer patients after injection of the antibody is described. 265 refs.; 30 figs.; 19 tabs

  13. Antibodies to Pseudogymnoascus destructans are not sufficient for protection against white-nose syndrome.

    Science.gov (United States)

    Johnson, Joseph S; Reeder, DeeAnn M; Lilley, Thomas M; Czirják, Gábor Á; Voigt, Christian C; McMichael, James W; Meierhofer, Melissa B; Seery, Christopher W; Lumadue, Shayne S; Altmann, Alexander J; Toro, Michael O; Field, Kenneth A

    2015-06-01

    White-nose syndrome (WNS) is a fungal disease caused by Pseudogymnoascus destructans (Pd) that affects bats during hibernation. Although millions of bats have died from WNS in North America, mass mortality has not been observed among European bats infected by the fungus, leading to the suggestion that bats in Europe are immune. We tested the hypothesis that an antibody-mediated immune response can provide protection against WNS by quantifying antibodies reactive to Pd in blood samples from seven species of free-ranging bats in North America and two free-ranging species in Europe. We also quantified antibodies in blood samples from little brown myotis (Myotis lucifugus) that were part of a captive colony that we injected with live Pd spores mixed with adjuvant, as well as individuals surviving a captive Pd infection trial. Seroprevalence of antibodies against Pd, as well as antibody titers, was greater among little brown myotis than among four other species of cave-hibernating bats in North America, including species with markedly lower WNS mortality rates. Among little brown myotis, the greatest titers occurred in populations occupying regions with longer histories of WNS, where bats lacked secondary symptoms of WNS. We detected antibodies cross-reactive with Pd among little brown myotis naïve to the fungus. We observed high titers among captive little brown myotis injected with Pd. We did not detect antibodies against Pd in Pd-infected European bats during winter, and titers during the active season were lower than among little brown myotis. These results show that antibody-mediated immunity cannot explain survival of European bats infected with Pd and that little brown myotis respond differently to Pd than species with higher WNS survival rates. Although it appears that some species of bats in North America may be developing resistance to WNS, an antibody-mediated immune response does not provide an explanation for these remnant populations.

  14. The Mediating Role of Insight for Long-Term Improvements in Psychodynamic Therapy

    Science.gov (United States)

    Johansson, Paul; Hoglend, Per; Ulberg, Randi; Amlo, Svein; Marble, Alice; Bogwald, Kjell-Petter; Sorbye, Oystein; Sjaastad, Mary Cosgrove; Heyerdahl, Oscar

    2010-01-01

    Objective: According to psychoanalytic theory, interpretation of transference leads to increased insight that again leads to improved interpersonal functioning over time. In this study, we performed a full mediational analysis to test whether insight gained during treatment mediates the long-term effects of transference interpretation in dynamic…

  15. Therapeutic antibodies as a treatment option for dengue fever.

    Science.gov (United States)

    Chan, Kuan Rong; Ong, Eugenia Z; Ooi, Eng Eong

    2013-11-01

    Dengue fever is the most prevalent mosquito-borne viral disease globally with about 100 million cases of acute dengue annually. Severe dengue infection can result in a life-threatening illness. In the absence of either a licensed vaccine or antiviral drug against dengue, therapeutic antibodies that neutralize dengue virus (DENV) may serve as an effective medical countermeasure against severe dengue. However, therapeutic antibodies would need to effectively neutralize all four DENV serotypes. It must not induce antibody-dependent enhancement of DENV infection in monocytes/macrophages through Fc gamma receptor (FcγR)-mediated phagocytosis, which is hypothesized to increase the risk of severe dengue. Here, we review the strategies and technologies that can be adopted to develop antibodies for therapeutic applications. We also discuss the mechanism of antibody neutralization in the cells targeted by DENV that express Fc gamma receptor. These studies have provided significant insight toward the use of therapeutic antibodies as a potentially promising bulwark against dengue.

  16. Future of antibody purification.

    Science.gov (United States)

    Low, Duncan; O'Leary, Rhona; Pujar, Narahari S

    2007-03-15

    Antibody purification seems to be safely ensconced in a platform, now well-established by way of multiple commercialized antibody processes. However, natural evolution compels us to peer into the future. This is driven not only by a large, projected increase in the number of antibody therapies, but also by dramatic improvements in upstream productivity, and process economics. Although disruptive technologies have yet escaped downstream processes, evolution of the so-called platform is already evident in antibody processes in late-stage development. Here we perform a wide survey of technologies that are competing to be part of that platform, and provide our [inherently dangerous] assessment of those that have the most promise.

  17. Effects of CTLA4-Fc on glomerular injury in humorally-mediated glomerulonephritis in BALB/c mice.

    Science.gov (United States)

    Kitching, A R; Huang, X R; Ruth, A-J; Tipping, P G; Holdsworth, S R

    2002-06-01

    The effect of cytotoxic T-lymphocyte-associated molecule 4-immunoglobulin fusion protein (CTLA4-Fc) on humorally-mediated glomerulonephritis was studied in accelerated anti-glomerular basement membrane (anti-GBM) glomerulonephritis induced in BALB/c mice. This strain of mice develops antibody and complement dependent glomerulonephritis under this protocol. Sensitized BALB/c mice developed high levels of circulating autologous antibody titres, intense glomerular deposition of mouse immunoglobulin and complement, significant proteinuria, renal impairment, significant glomerular necrosis and a minor component of crescent formation 10 days after challenge with a nephritogenic antigen (sheep anti-GBM globulin). Early treatment during the primary immune response, or continuous treatment throughout the disease with CTLA4-Fc, significantly suppressed mouse anti-sheep globulin antibody titres in serum, and immunoglobulin and complement deposition in glomeruli. The degree of glomerular necrosis was improved and proteinuria was reduced, particularly in the earlier stages of disease. Late treatment by CTLA4-Fc starting one day after challenge with sheep anti-mouse GBM did not affect antibody production and did not attenuate glomerulonephritis. The low level of crescent formation found in BALB/c mice developing glomerulonephritis was not prevented by the administration of CTLA4-Fc. These results demonstrate that CTLA4-Fc is of benefit in this model of glomerulonephritis by its capacity to attenuate antibody production, without affecting the minor degree of cell-mediated glomerular injury.

  18. Antibodies against linear epitopes on Goodpasture autoantigen in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis.

    Science.gov (United States)

    Jia, Xiao-Yu; Yu, Jun-Tao; Hu, Shui-Yi; Li, Jian-Nan; Wang, Miao; Wang, Chen; Chen, Min; Cui, Zhao; Zhao, Ming-Hui

    2017-09-01

    In a substantial number of patients with crescentic glomerulonephritis, both anti-glomerular basement membrane (GBM) antibodies and anti-neutrophil cytoplasmic antibodies (ANCA) are detected simultaneously. ANCA is presumed to be the initial event but the mechanism is unknown. In the present study, we investigated the antibodies against linear epitopes on Goodpasture autoantigen in sera from patients with ANCA-associated vasculitis, aiming to reveal the mechanisms of the coexistence of the two kinds of autoantibodies. Thirty-one patients with ANCA-associated vasculitis were enrolled in this study. Twenty-four overlapping linear peptides were synthesized across the whole sequence of Goodpasture autoantigen. Serum antibodies against linear peptides were detected by ELISA and their associations with clinical features were further analyzed. Twenty-five out of the thirty-one (80.6%) sera from patients with ANCA-associated vasculitis possessed antibodies against linear peptides on Goodpasture autoantigen. These antibodies could be detected in 50% of patients with normal renal function (Scr ≤ 133 μmol/L), 70% of patients with moderate renal dysfunction (133 μmol/L  600 μmol/L) (P = 0.032). The highest recognition frequencies were found for peptides P4 (51.6%), P14 (54.8%), and P24 (54.8%), which contained the sequences that constitute the conformational epitopes of E A (P4) and E B (P14) recognized by anti-GBM antibodies. The level of anti-P4 antibodies was positively correlated with the percentage of crescents in glomeruli (r = 0.764, P = 0.027). Patients with anti-P24 antibodies had a significantly higher prevalence of renal dysfunction on diagnosis (88.2 vs. 42.9%, P = 0.018). Antibodies against linear epitopes on Goodpasture autoantigen could be detected in sera of patients with ANCA-associated vasculitis, which might mediate the production of antibodies towards the conformational epitopes on Goodpasture autoantigen, namely, the anti-GBM antibodies.

  19. ICARE improves antinuclear antibody detection by overcoming the barriers preventing accreditation.

    Science.gov (United States)

    Bertin, Daniel; Mouhajir, Yassin; Bongrand, Pierre; Bardin, Nathalie

    2016-02-15

    Antinuclear antibodies (ANA) are useful biomarkers for the diagnosis and the monitoring of rheumatic diseases. The American College of Rheumatology has stated that indirect immunofluorescence (IIF) analysis remains the gold standard for ANA screening. However, IIF is time consuming, subjective, not fully standardized and presents several issues for accreditation which is the process leading to ISO 15189 certification for medical laboratories. We propose an innovative tool for accreditation by using the quantitative evaluation of the automated image capture and analysis "ICARE" (Immunofluorescence for Computed Antinuclear antibody Rational Evaluation). We established the optimal screening dilution (1:160) and a fluorescence index (FI) cutoff for ICARE on a cohort of 91 healthy blood donors. Then, we evaluated performance of ICARE on a routine cohort of 236 patients. Precision parameters of ANA detection by IIF were evaluated according to ISO 15189. ICARE showed an excellent concordance with visual evaluation (88%, Kappa=0.76) and significantly discriminated between weak to moderate (1:160-1:320 titers) and high (>1:320 titers) ANA levels. A significant correlation was found between FI and ANA titers (Spearman's ρ=0.67; Pprocess of continuous improvement of the quality of clinical laboratories. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Homogeneous plate based antibody internalization assay using pH sensor fluorescent dye.

    Science.gov (United States)

    Nath, Nidhi; Godat, Becky; Zimprich, Chad; Dwight, Stephen J; Corona, Cesear; McDougall, Mark; Urh, Marjeta

    2016-04-01

    Receptor-mediated antibody internalization is a key mechanism underlying several anti-cancer antibody therapeutics. Delivering highly toxic drugs to cancer cells, as in the case of antibody drug conjugates (ADCs), efficient removal of surface receptors from cancer cells and changing the pharmacokinetics profile of the antibody drugs are some of key ways that internalization impacts the therapeutic efficacy of the antibodies. Over the years, several techniques have been used to study antibody internalization including radiolabels, fluorescent microscopy, flow cytometry and cellular toxicity assays. While these methods allow analysis of internalization, they have limitations including a multistep process and limited throughput and are generally endpoint assays. Here, we present a new homogeneous method that enables time and concentration dependent measurements of antibody internalization. The method uses a new hydrophilic and bright pH sensor dye (pHAb dye), which is not fluorescent at neutral pH but becomes highly fluorescent at acidic pH. For receptor mediated antibody internalization studies, antibodies against receptors are conjugated with the pHAb dye and incubated with the cells expressing the receptors. Upon binding to the receptor, the dyes conjugated to the antibody are not fluorescent because of the neutral pH of the media, but upon internalization and trafficking into endosomal and lysosomal vesicles the pH drops and dyes become fluorescent. The enabling attributes of the pHAb dyes are the hydrophilic nature to minimize antibody aggregation and bright fluorescence at acidic pH which allows development of simple plate based assays using a fluorescent reader. Using two different therapeutic antibodies--Trastuzumab (anti-HER2) and Cetuximab (anti-EGFR)--we show labeling with pHAb dye using amine and thiol chemistries and impact of chemistry and dye to antibody ration on internalization. We finally present two new approaches using the pHAb dye, which will be

  1. Infection of CD4+ T lymphocytes by the human T cell leukemia virus type 1 is mediated by the glucose transporter GLUT-1: Evidence using antibodies specific to the receptor's large extracellular domain

    International Nuclear Information System (INIS)

    Jin, Qingwen; Agrawal, Lokesh; VanHorn-Ali, Zainab; Alkhatib, Ghalib

    2006-01-01

    To analyze HTLV-1 cytotropism, we developed a highly sensitive vaccinia virus-based assay measuring activation of a reporter gene upon fusion of two distinct cell populations. We used this system in a functional cDNA screening to isolate and confirm that the glucose transporter protein 1 (GLUT-1) is a receptor for HTLV-1. GLUT-1 is a ubiquitously expressed plasma membrane glycoprotein with 12 transmembrane domains and 6 extracellular loops (ECL). We demonstrate for the first time that peptide antibodies (GLUT-IgY) raised in chicken to the large extracellular loop (ECL1) detect GLUT-1 at the cell surface and inhibit envelope (Env)-mediated fusion and infection. Efficient GLUT-IgY staining was detected with peripheral blood CD4 + lymphocytes purified by positive selection. Further, GLUT-IgY caused efficient inhibition of Env-mediated fusion and infection of CD4 + T and significantly lower inhibition of CD8 + T lymphocytes. The specificity of GLUT-IgY antibodies to GLUT-1 was demonstrated by ECL1 peptide competition studies. Grafting ECL1 of GLUT-1 onto the receptor-negative GLUT-3 conferred significant receptor activity. In contrast, grafting ECL1 of GLUT-3 onto GLUT-1 resulted in a significant loss of the receptor activity. The ECL1-mediated receptor activity was efficiently blocked with four different human monoclonal antibody (HMab) to HTLV-1 Env. The ECL1-derived peptide blocked HTLV-1 Env-mediated fusion with several nonhuman mammalian cell lines. The results demonstrate the utilization of cell surface GLUT-1 in HTLV-1 infection of CD4 + T lymphocytes and implicate a critical role for the ECL1 region in viral tropism

  2. Antibody tumor penetration

    Science.gov (United States)

    Thurber, Greg M.; Schmidt, Michael M.; Wittrup, K. Dane

    2009-01-01

    Antibodies have proven to be effective agents in cancer imaging and therapy. One of the major challenges still facing the field is the heterogeneous distribution of these agents in tumors when administered systemically. Large regions of untargeted cells can therefore escape therapy and potentially select for more resistant cells. We present here a summary of theoretical and experimental approaches to analyze and improve antibody penetration in tumor tissue. PMID:18541331

  3. A Functional Role for Antibodies in Tuberculosis.

    Science.gov (United States)

    Lu, Lenette L; Chung, Amy W; Rosebrock, Tracy R; Ghebremichael, Musie; Yu, Wen Han; Grace, Patricia S; Schoen, Matthew K; Tafesse, Fikadu; Martin, Constance; Leung, Vivian; Mahan, Alison E; Sips, Magdalena; Kumar, Manu P; Tedesco, Jacquelynne; Robinson, Hannah; Tkachenko, Elizabeth; Draghi, Monia; Freedberg, Katherine J; Streeck, Hendrik; Suscovich, Todd J; Lauffenburger, Douglas A; Restrepo, Blanca I; Day, Cheryl; Fortune, Sarah M; Alter, Galit

    2016-10-06

    While a third of the world carries the burden of tuberculosis, disease control has been hindered by a lack of tools, including a rapid, point-of-care diagnostic and a protective vaccine. In many infectious diseases, antibodies (Abs) are powerful biomarkers and important immune mediators. However, in Mycobacterium tuberculosis (Mtb) infection, a discriminatory or protective role for humoral immunity remains unclear. Using an unbiased antibody profiling approach, we show that individuals with latent tuberculosis infection (Ltb) and active tuberculosis disease (Atb) have distinct Mtb-specific humoral responses, such that Ltb infection is associated with unique Ab Fc functional profiles, selective binding to FcγRIII, and distinct Ab glycosylation patterns. Moreover, compared to Abs from Atb, Abs from Ltb drove enhanced phagolysosomal maturation, inflammasome activation, and, most importantly, macrophage killing of intracellular Mtb. Combined, these data point to a potential role for Fc-mediated Ab effector functions, tuned via differential glycosylation, in Mtb control. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Structure-based, targeted deglycosylation of HIV-1 gp120 and effects on neutralization sensitivity and antibody recognition

    International Nuclear Information System (INIS)

    Koch, Markus; Pancera, Marie; Kwong, Peter D.; Kolchinsky, Peter; Grundner, Christoph; Wang Liping; Hendrickson, Wayne A.; Sodroski, Joseph; Wyatt, Richard

    2003-01-01

    The human immunodeficiency virus (HIV-1) exterior envelope glycoprotein, gp120, mediates receptor binding and is the major target for neutralizing antibodies. Primary HIV-1 isolates are characteristically more resistant to broadly neutralizing antibodies, although the structural basis for this resistance remains obscure. Most broadly neutralizing antibodies are directed against functionally conserved gp120 regions involved in binding to either the primary virus receptor, CD4, or the viral coreceptor molecules that normally function as chemokine receptors. These antibodies are known as CD4 binding site (CD4BS) and CD4-induced (CD4i) antibodies, respectively. Inspection of the gp120 crystal structure reveals that although the receptor-binding regions lack glycosylation, sugar moieties lie proximal to both receptor-binding sites on gp120 and thus in proximity to both the CD4BS and the CD4i epitopes. In this study, guided by the X-ray crystal structure of gp120, we deleted four N-linked glycosylation sites that flank the receptor-binding regions. We examined the effects of selected changes on the sensitivity of two prototypic HIV-1 primary isolates to neutralization by antibodies. Surprisingly, removal of a single N-linked glycosylation site at the base of the gp120 third variable region (V3 loop) increased the sensitivity of the primary viruses to neutralization by CD4BS antibodies. Envelope glycoprotein oligomers on the cell surface derived from the V3 glycan-deficient virus were better recognized by a CD4BS antibody and a V3 loop antibody than were the wild-type glycoproteins. Absence of all four glycosylation sites rendered a primary isolate sensitive to CD4i antibody-mediated neutralization. Thus, carbohydrates that flank receptor-binding regions on gp120 protect primary HIV-1 isolates from antibody-mediated neutralization

  5. Enhanced sensitivity in detection of antiviral antibody responses using biotinylation of foot-and-mouth disease virus (FMDV) capsids.

    Science.gov (United States)

    Kenney, Mary; Waters, Ryan A; Rieder, Elizabeth; Pega, Juan; Perez-Filguera, Mariano; Golde, William T

    2017-11-01

    Analysis of the immune response to infection of livestock by foot-and-mouth disease virus (FMDV) is most often reported as the serum antibody response to the virus. While measurement of neutralizing antibody has been sensitive and specific, measurements of the quality of the antibody response are less robust. Determining the immunoglobulin (Ig) isotype of the serum antibody response provides a deeper understanding of the biology of the response and more sensitive methods for these assays will facilitate analyses of B cell mediated immunity. We tested the hypothesis that using the virus as the molecular probe could be achieved by adding tags to the surface of the FMDV capsid, and that would enhance sensitivity in assays for anti-FMDV antibody responses. The use of a FLAG-tagged virus in these assays failed to yield improvement whereas chemically biotinylating the virus capsid resulted in significant enhancement of the signal. Here we describe methods using biotinylated virus for measuring anti-viral antibody in serum and antibody secreting cells (ASCs) in blood that are sensitive and specific. Finally, we describe using the biotinylated virus in flow cytometry where such assays should greatly enhance the analysis of anti-virus antibody producing B cells, allowing the investigator to focus on only the FMDV specific B cells when analyzing the development of the B cell response to either infection or vaccination. Published by Elsevier B.V.

  6. Conformational Occlusion of Blockade Antibody Epitopes, a Novel Mechanism of GII.4 Human Norovirus Immune Evasion.

    Science.gov (United States)

    Lindesmith, Lisa C; Mallory, Michael L; Debbink, Kari; Donaldson, Eric F; Brewer-Jensen, Paul D; Swann, Excel W; Sheahan, Timothy P; Graham, Rachel L; Beltramello, Martina; Corti, Davide; Lanzavecchia, Antonio; Baric, Ralph S

    2018-01-01

    Extensive antigenic diversity within the GII.4 genotype of human norovirus is a major driver of pandemic emergence and a significant obstacle to development of cross-protective immunity after natural infection and vaccination. However, human and mouse monoclonal antibody studies indicate that, although rare, antibodies to conserved GII.4 blockade epitopes are generated. The mechanisms by which these epitopes evade immune surveillance are uncertain. Here, we developed a new approach for identifying conserved GII.4 norovirus epitopes. Utilizing a unique set of virus-like particles (VLPs) representing the in vivo -evolved sequence diversity within an immunocompromised person, we identify key residues within epitope F, a conserved GII.4 blockade antibody epitope. The residues critical for antibody binding are proximal to evolving blockade epitope E. Like epitope F, antibody blockade of epitope E was temperature sensitive, indicating that particle conformation regulates antibody access not only to the conserved GII.4 blockade epitope F but also to the evolving epitope E. These data highlight novel GII.4 mechanisms to protect blockade antibody epitopes, map essential residues of a GII.4 conserved epitope, and expand our understanding of how viral particle dynamics may drive antigenicity and antibody-mediated protection by effectively shielding blockade epitopes. Our data support the notion that GII.4 particle breathing may well represent a major mechanism of humoral immune evasion supporting cyclic pandemic virus persistence and spread in human populations. IMPORTANCE In this study, we use norovirus virus-like particles to identify key residues of a conserved GII.4 blockade antibody epitope. Further, we identify an additional GII.4 blockade antibody epitope to be occluded, with antibody access governed by temperature and particle dynamics. These findings provide additional support for particle conformation-based presentation of binding residues mediated by a particle

  7. Another Piece of the Antibody Puzzle: Observations from the HALT study\\.

    Science.gov (United States)

    Snyder, Laurie D; Tinckam, Kathryn J

    2018-06-04

    In the rapidly evolving domain of clinical transplantation immunobiology, the interrogation and interpretation of HLA antibodies and their associated clinical consequences are in the spotlight. In lung transplant, HLA antibodies, in particular donor specific antibodies (DSA), are a determining component of the lung transplant antibody mediated rejection (AMR) definition (1). DSA after lung transplant are widely regarded as poor prognosticator, though sparse data to date necessitate ongoing discourse and continued investigation into incidence, timing and treatment. Prior studies reported a wide range of DSA incidence with differing consequences on a background of highly variable timing, methods, antibody analytic strategies and clinical definitions. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  8. The Perfect Storm: HLA Antibodies, Complement, FcγRs and Endothelium in Transplant Rejection

    OpenAIRE

    Thomas, Kimberly A.; Valenzuela, Nicole M.; Reed, Elaine F.

    2015-01-01

    The pathophysiology of antibody-mediated rejection (AMR) in solid organ transplants is multi-faceted and predominantly caused by antibodies directed against polymorphic donor human leukocyte antigens (HLA). Despite the clearly detrimental impact of HLA antibodies (HLA-Ab) on graft function and survival, the prevention, diagnosis and treatment of AMR remain a challenge. Histological manifestations of AMR reflect signatures of HLA-Ab-triggered injury, specifically endothelial changes, recipient...

  9. Immune TB Antibody Phage Display Library as a Tool To Study B Cell Immunity in TB Infections.

    Science.gov (United States)

    Hamidon, Nurul Hamizah; Suraiya, Siti; Sarmiento, Maria E; Acosta, Armando; Norazmi, Mohd Nor; Lim, Theam Soon

    2018-03-01

    B cells and in particular antibodies has always played second fiddle to cellular immunity in regard to tuberculosis (TB). However, recent studies has helped position humoral immunity especially antibodies back into the foray in relation to TB immunity. Therefore, the ability to correlate the natural antibody responses of infected individuals toward TB antigens would help strengthen this concept. Phage display is an intriguing approach that can be utilized to study antibody-mediated responses against a particular infection via harvesting the B cell repertoire from infected individuals. The development of disease-specific antibody libraries or immune libraries is useful to better understand antibody-mediated immune responses against specific disease antigens. This study describes the generation of an immune single-chain variable fragment (scFv) library derived from TB-infected individuals. The immune library with an estimated diversity of 10 9 independent clones was then applied for the identification of monoclonal antibodies against Mycobacterium tuberculosis α-crystalline as a model antigen. Biopanning of the library isolated three monoclonal antibodies with unique gene usage. This strengthens the role of antibodies in TB immunity in addition to the role played by cellular immunity. The developed library can be applied against other TB antigens and aid antibody-derived TB immunity studies in the future.

  10. B lymphocyte depletion with the monoclonal antibody rituximab in Graves' disease: a controlled pilot study

    DEFF Research Database (Denmark)

    El Fassi, Daniel; Nielsen, Claus H; Bonnema, Steen J

    2007-01-01

    Graves' disease (GD) is a common TSH receptor autoantibody (TRAb)-mediated disorder. Because B lymphocytes are important self-antigen presenting cells and precursors for antibody-secreting plasma cells, temporary B-lymphocyte depletion with the monoclonal antibody rituximab (RTX) might...

  11. Lack of protection following passive transfer of polyclonal highly functional low-dose non-neutralizing antibodies.

    Directory of Open Access Journals (Sweden)

    Anne-Sophie Dugast

    Full Text Available Recent immune correlates analysis from the RV144 vaccine trial has renewed interest in the role of non-neutralizing antibodies in mediating protection from infection. While neutralizing antibodies have proven difficult to induce through vaccination, extra-neutralizing antibodies, such as those that mediate antibody-dependent cellular cytotoxicity (ADCC, are associated with long-term control of infection. However, while several non-neutralizing monoclonal antibodies have been tested for their protective efficacy in vivo, no studies to date have tested the protective activity of naturally produced polyclonal antibodies from individuals harboring potent ADCC activity. Because ADCC-inducing antibodies are highly enriched in elite controllers (EC, we passively transferred highly functional non-neutralizing polyclonal antibodies, purified from an EC, to assess the potential impact of polyclonal non-neutralizing antibodies on a stringent SHIV-SF162P3 challenge in rhesus monkeys. Passive transfer of a low-dose of ADCC inducing antibodies did not protect from infection following SHIV-SF162P3 challenge. Passively administered antibody titers and gp120-specific, but not gp41-specific, ADCC and antibody induced phagocytosis (ADCP were detected in the majority of the monkeys, but did not correlate with post infection viral control. Thus these data raise the possibility that gp120-specific ADCC activity alone may not be sufficient to control viremia post infection but that other specificities or Fc-effector profiles, alone or in combination, may have an impact on viral control and should be tested in future passive transfer experiments.

  12. The effect of daily co-trimoxazole prophylaxis on natural development of antibody-mediated immunity against P. falciparum malaria infection in HIV-exposed uninfected Malawian children.

    Science.gov (United States)

    Longwe, Herbert; Jambo, Kondwani C; Phiri, Kamija S; Mbeye, Nyanyiwe; Gondwe, Thandile; Hall, Tom; Tetteh, Kevin K A; Drakeley, Chris; Mandala, Wilson L

    2015-01-01

    Co-trimoxazole prophylaxis, currently recommended in HIV-exposed, uninfected (HEU) children as protection against opportunistic infections, also has some anti-malarial efficacy. We determined whether daily co-trimoxazole prophylaxis affects the natural development of antibody-mediated immunity to blood-stage Plasmodium falciparum malaria infection. Using an enzyme-linked immunosorbent assay, we measured antibodies to 8 Plasmodium falciparum antigens (AMA-1, MSP-119, MSP-3, PfSE, EBA-175RII, GLURP R0, GLURP R2 and CSP) in serum samples from 33 HEU children and 31 HIV-unexposed, uninfected (HUU) children, collected at 6, 12 and 18 months of age. Compared to HIV-uninfected children, HEU children had significantly lower levels of specific IgG against AMA-1 at 6 months (p = 0.001), MSP-119 at 12 months (p = 0.041) and PfSE at 6 months (p = 0.038), 12 months (p = 0.0012) and 18 months (p = 0.0097). No differences in the IgG antibody responses against the rest of the antigens were observed between the two groups at all time points. The breadth of specificity of IgG response was reduced in HEU children compared to HUU children during the follow up period. Co-trimoxazole prophylaxis seems to reduce IgG antibody responses to P. falciparum blood stage antigens, which could be as a result of a reduction in exposure of those children under this regime. Although antibody responses were regarded as markers of exposure in this study, further studies are required to establish whether these responses are correlated in any way to clinical immunity to malaria.

  13. Monoclonal antibodies targeting CD38 in hematological malignancies and beyond

    DEFF Research Database (Denmark)

    van de Donk, Niels W C J; Janmaat, Maarten L.; Mutis, Tuna

    2016-01-01

    CD38 is a multifunctional cell surface protein that has receptor as well as enzyme functions. The protein is generally expressed at low levels on various hematological and solid tissues, while plasma cells express particularly high levels of CD38. The protein is also expressed in a subset of hema...... strong anti-tumor activity in preclinical models. The antibody engages diverse mechanisms of action, including complement-dependent cytotoxicity, antibody-dependent cellular cytotoxicity, antibody-dependent cellular phagocytosis, programmed cell death, modulation of enzymatic activity...... combination therapies with existing as well as emerging therapies, which are currently evaluated in the clinic. Finally, CD38 antibodies may have a role in the treatment of diseases beyond hematological malignancies, including solid tumors and antibody-mediated autoimmune diseases. © 2016 John Wiley & Sons A....../S. Published by John Wiley & Sons Ltd....

  14. C1 Inhibitor in Acute Antibody-Mediated Rejection Nonresponsive to Conventional Therapy in Kidney Transplant Recipients: A Pilot Study.

    Science.gov (United States)

    Viglietti, D; Gosset, C; Loupy, A; Deville, L; Verine, J; Zeevi, A; Glotz, D; Lefaucheur, C

    2016-05-01

    Complement inhibitors have not been thoroughly evaluated in the treatment of acute antibody-mediated rejection (ABMR). We performed a prospective, single-arm pilot study to investigate the potential effects and safety of C1 inhibitor (C1-INH) Berinert added to high-dose intravenous immunoglobulin (IVIG) for the treatment of acute ABMR that is nonresponsive to conventional therapy. Kidney recipients with nonresponsive active ABMR and acute allograft dysfunction were enrolled between April 2013 and July 2014 and received C1-INH and IVIG for 6 months (six patients). The primary end point was the change in eGFR at 6 months after inclusion (M+6). Secondary end points included the changes in histology and DSA characteristics and adverse events as evaluated at M+6. All patients showed an improvement in eGFR between inclusion and M+6: from 38.7 ± 17.9 to 45.2 ± 21.3 mL/min/1.73 m(2) (p = 0.0277). There was no change in histological features, except a decrease in the C4d deposition rate from 5/6 to 1/6 (p = 0.0455). There was a change in DSA C1q status from 6/6 to 1/6 positive (p = 0.0253). One deep venous thrombosis was observed. In a secondary analysis, C1-INH patients were compared with a similar historical control group (21 patients). C1-INH added to IVIG is safe and may improve allograft function in kidney recipients with nonresponsive acute ABMR. © Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.

  15. Chronic Antibody-Mediated Rejection in Nonhuman Primate Renal Allografts: Validation of Human Histological and Molecular Phenotypes.

    Science.gov (United States)

    Adam, B A; Smith, R N; Rosales, I A; Matsunami, M; Afzali, B; Oura, T; Cosimi, A B; Kawai, T; Colvin, R B; Mengel, M

    2017-11-01

    Molecular testing represents a promising adjunct for the diagnosis of antibody-mediated rejection (AMR). Here, we apply a novel gene expression platform in sequential formalin-fixed paraffin-embedded samples from nonhuman primate (NHP) renal transplants. We analyzed 34 previously described gene transcripts related to AMR in humans in 197 archival NHP samples, including 102 from recipients that developed chronic AMR, 80 from recipients without AMR, and 15 normal native nephrectomies. Three endothelial genes (VWF, DARC, and CAV1), derived from 10-fold cross-validation receiver operating characteristic curve analysis, demonstrated excellent discrimination between AMR and non-AMR samples (area under the curve = 0.92). This three-gene set correlated with classic features of AMR, including glomerulitis, capillaritis, glomerulopathy, C4d deposition, and DSAs (r = 0.39-0.63, p < 0.001). Principal component analysis confirmed the association between three-gene set expression and AMR and highlighted the ambiguity of v lesions and ptc lesions between AMR and T cell-mediated rejection (TCMR). Elevated three-gene set expression corresponded with the development of immunopathological evidence of rejection and often preceded it. Many recipients demonstrated mixed AMR and TCMR, suggesting that this represents the natural pattern of rejection. These data provide NHP animal model validation of recent updates to the Banff classification including the assessment of molecular markers for diagnosing AMR. © 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.

  16. Antibody-mediated neutralization of Ebola virus can occur by two distinct mechanisms

    International Nuclear Information System (INIS)

    Shedlock, Devon J.; Bailey, Michael A.; Popernack, Paul M.; Cunningham, James M.; Burton, Dennis R.; Sullivan, Nancy J.

    2010-01-01

    Human Ebola virus causes severe hemorrhagic fever disease with high mortality and there is no vaccine or treatment. Antibodies in survivors occur early, are sustained, and can delay infection when transferred into nonhuman primates. Monoclonal antibodies (mAbs) from survivors exhibit potent neutralizing activity in vitro and are protective in rodents. To better understand targets and mechanisms of neutralization, we investigated a panel of mAbs shown previously to react with the envelope glycoprotein (GP). While one non-neutralizing mAb recognized a GP epitope in the nonessential mucin-like domain, the rest were specific for GP1, were neutralizing, and could be further distinguished by reactivity with secreted GP. We show that survivor antibodies, human KZ52 and monkey JP3K11, were specific for conformation-dependent epitopes comprising residues in GP1 and GP2 and that neutralization occurred by two distinct mechanisms; KZ52 inhibited cathepsin cleavage of GP whereas JP3K11 recognized the cleaved, fusion-active form of GP.

  17. An improved autoradiographic technique for the detection of antibody-forming cells

    International Nuclear Information System (INIS)

    Mason, D.W.

    1976-01-01

    An autoradiographic technique for the detection of antibody-forming cells has been developed for the assay of anti-DNP responses. The lymphoid cell suspension to be assayed was allowed to sediment on to a glass slide coated with DNP-conjugated gelatin to which the secreted antibody bound during subsequent incubation. The bound antibody and its Ig class was revealed by a second incubation using 125 I-anti-immunoglobulin reagents followed by autoradiography. Studies on the sensitivity and specificity of the method are presented and its advantages over other techniques described. The technique should be readily applicable to other haptens

  18. Targeting Malignant Brain Tumors with Antibodies

    Directory of Open Access Journals (Sweden)

    Rok Razpotnik

    2017-09-01

    Full Text Available Antibodies have been shown to be a potent therapeutic tool. However, their use for targeting brain diseases, including neurodegenerative diseases and brain cancers, has been limited, particularly because the blood–brain barrier (BBB makes brain tissue hard to access by conventional antibody-targeting strategies. In this review, we summarize new antibody therapeutic approaches to target brain tumors, especially malignant gliomas, as well as their potential drawbacks. Many different brain delivery platforms for antibodies have been studied such as liposomes, nanoparticle-based systems, cell-penetrating peptides (CPPs, and cell-based approaches. We have already shown the successful delivery of single-chain fragment variable (scFv with CPP as a linker between two variable domains in the brain. Antibodies normally face poor penetration through the BBB, with some variants sufficiently passing the barrier on their own. A “Trojan horse” method allows passage of biomolecules, such as antibodies, through the BBB by receptor-mediated transcytosis (RMT. Such examples of therapeutic antibodies are the bispecific antibodies where one binding specificity recognizes and binds a BBB receptor, enabling RMT and where a second binding specificity recognizes an antigen as a therapeutic target. On the other hand, cell-based systems such as stem cells (SCs are a promising delivery system because of their tumor tropism and ability to cross the BBB. Genetically engineered SCs can be used in gene therapy, where they express anti-tumor drugs, including antibodies. Different types and sources of SCs have been studied for the delivery of therapeutics to the brain; both mesenchymal stem cells (MSCs and neural stem cells (NSCs show great potential. Following the success in treatment of leukemias and lymphomas, the adoptive T-cell therapies, especially the chimeric antigen receptor-T cells (CAR-Ts, are making their way into glioma treatment as another type of cell

  19. Anti-inflammatory activity of human IgG4 antibodies by dynamic Fab arm exchange

    NARCIS (Netherlands)

    van der Neut Kolfschoten, Marijn; Schuurman, Janine; Losen, Mario; Bleeker, Wim K.; Martínez-Martínez, Pilar; Vermeulen, Ellen; den Bleker, Tamara H.; Wiegman, Luus; Vink, Tom; Aarden, Lucien A.; de Baets, Marc H.; van de Winkel, Jan G. J.; Aalberse, Rob C.; Parren, Paul W. H. I.

    2007-01-01

    Antibodies play a central role in immunity by forming an interface with the innate immune system and, typically, mediate proinflammatory activity. We describe a novel posttranslational modification that leads to anti-inflammatory activity of antibodies of immunoglobulin G, isotype 4 (IgG4). IgG4

  20. Biodistribution and endocytosis of ICAM-1-targeting antibodies versus nanocarriers in the gastrointestinal tract in mice

    Directory of Open Access Journals (Sweden)

    Mane V

    2012-08-01

    Full Text Available Viraj Mane,1 Silvia Muro1, 21Institute for Bioscience and Biotechnology Research, 2Fischell Department of Bioengineering, University of Maryland, College Park, MD, USAAbstract: Drug delivery to the gastrointestinal (GI tract is key for improving treatment of GI maladies, developing oral vaccines, and facilitating drug transport into circulation. However, delivery of formulations to the GI tract is hindered by pH changes, degradative enzymes, mucus, and peristalsis, leading to poor GI retention. Targeting may prolong residence of therapeutics in the GI tract and enhance their interaction with this tissue, improving such aspects. We evaluated nanocarrier (NC and ligand-mediated targeting in the GI tract following gastric gavage in mice. We compared GI biodistribution, degradation, and endocytosis between control antibodies and antibodies targeting the cell surface determinant intercellular adhesion molecule 1 (ICAM-1, expressed on GI epithelium and other cell types. These antibodies were administered either as free entities or coated onto polymer NCs. Fluorescence and radioisotope tracing showed proximal accumulation, with preferential retention in the stomach, jejunum, and ileum; and minimal presence in the duodenum, cecum, and colon by 1 hour after administration. Upstream (gastric retention was enhanced in NC formulations, with decreased downstream (jejunal accumulation. Of the total dose delivered to the GI tract, ~60% was susceptible to enzymatic (but not pH-mediated degradation, verified both in vitro and in vivo. Attenuation of peristalsis by sedation increased upstream retention (stomach, duodenum, and jejunum. Conversely, alkaline NaHCO3, which enhances GI transit by decreasing mucosal viscosity, favored downstream (ileal passage. This suggests passive transit through the GI tract, governed by mucoadhesion and peristalsis. In contrast, both free anti-ICAM and anti-ICAM NCs demonstrated significantly enhanced upstream (stomach and duodenum

  1. Preparation and characterization of chimeric CD19 monoclonal antibody

    International Nuclear Information System (INIS)

    Zola, H.; Macardle, P.J.; Bradford, T.; Weedon, H.; Yasui, H.; Kurosawa, Y.

    1991-01-01

    CD19 antibodies have been suggested as candidates for immunological attack on leukemic and lymphoma cells of the B lineage because the antigen is restricted to the B lineage. With the potential use of FMC63 in immunotherapy in mind a mouse-human chimera was produced in which the genes coding for the VDJ region of the heavy chain and the VJ region of the light chain derive from the FMC63 mouse hybridoma, while the C region genes code for human IgG1. The genes have been transfected back into a mouse myeloma line, which secretes low levels of immunoglobulin. (Ig). This Ig was purified and biotinylated in order to determine the specificity of the antibody. The chimeric antibody has a reaction profile concordant with the original FMC63 antibody, but has the properties of a human IgG1, including the ability to fix human complement. However, the antibody is not cytotoxic in vitro in the presence of complement or cells capable of mediating antibody-dependent cellular cytotoxicity. Possible reasons for this and ways of using the antibody are discussed. 47 refs., 7 figs

  2. Antibody-dependent cellular cytotoxicity (ADCC) activity of a novel anti-PD-L1 antibody avelumab (MSB0010718C) on human tumor cells

    Science.gov (United States)

    Fantini, Massimo; Heery, Christopher R.; Gulley, James L.; Tsang, Kwong Yok; Schlom, Jeffrey

    2015-01-01

    Several anti-PD1/PD-L1 monoclonal antibodies (MAb) are currently providing evidence of clinical benefit in subsets of cancer patients. The mode of action of these MAbs is to inhibit PD1 on immune cells interacting with PD-L1 on tumor cells. These MAbs are either designed or engineered to eliminate antibody-dependent cell-mediated cytotoxicity (ADCC), which, however, has been implicated as an important mechanism in several highly effective MAb-mediated cancer therapies. A fully human anti-PD-L1 MAb would potentially be able to block PD-L1/PD1 interactions and also mediate the ADCC lysis of tumor cells. MSB0010718C (designated avelumab) is a fully human IgG1 anti-PD-L1 MAb. The studies reported here demonstrate (a) the ability of avelumab to lyse a range of human tumor cells in the presence of PBMC or NK effectors; (b) IFNγ can enhance tumor cell PD-L1 expression and in some cases enhance ADCC tumor cell lysis; (c) purified NK cells are potent effectors for avelumab; (d) similar levels of avelumab-mediated ADCC lysis of tumor cells are seen using purified NK as effectors from either healthy donors or cancer patients; (e) very low levels of avelumab-mediated lysis are seen using whole PBMCs as targets; this finding complements results seen in analyses of PBMC subsets of patients receiving avelumab; and (f) the addition of IL12 to NK cells greatly enhances avelumab-mediated ADCC. These studies thus provide an additional mode of action for an anti-PD-L1 MAb and support the rationale for further studies to enhance avelumab-mediated ADCC activity. PMID:26014098

  3. Designing two-in-one antibodies.

    Science.gov (United States)

    Valladares, Ignacio Garcia; Espinoza, Luis R

    2009-09-01

    Evaluation of: Bostrom J, Shang-Fan Y, Kan D et al.: Variants of the antibody Herceptin that interact with HER2 and VEGF at the antigen binding site. Science 323, 1610-1614 (2009). The longstanding held notion that one antibody equals one antigen and, hence, one function has been challenged in recent years. Improved technology in antibody production, especially the accumulation of sequence data of immunoglobulin genes and the advent of PCR have made it possible to clone antibody gene repertoires. The current paper provides further challenge to the notion of one antibody = one antigen by developing 'two-in-one' antibodies with an antigen-binding site that binds two distinct proteins with high affinity. A therapeutic variant antibody of Herceptin (Genentech, CA, USA) was isolated that binds the human EGF receptor (HER)2 and also to VEGF. This development may represent a breakthrough discovery and may have significant implications in the therapy of malignant, infectious, allergic and autoimmune disorders.

  4. Immune-mediated steroid-responsive epileptic spasms and epileptic encephalopathy associated with VGKC-complex antibodies.

    Science.gov (United States)

    Suleiman, Jehan; Brenner, Tanja; Gill, Deepak; Troedson, Christopher; Sinclair, Adriane J; Brilot, Fabienne; Vincent, Angela; Lang, Bethan; Dale, Russell C

    2011-11-01

    Autoantibodies that bind to voltage-gated potassium-channel complex proteins (VGKC-complex antibodies) occur frequently in adults with limbic encephalitis presenting with cognitive impairment and seizures. Recently, VGKC-complex antibodies have been described in a few children with limbic encephalitis, and children with unexplained encephalitis presenting with status epilepticus. We report a case of infantile-onset epileptic spasms and developmental delay compatible with epileptic encephalopathy. Our patient was a female infant, aged 4 months at presentation. She had evidence of immune activation in the central nervous system with elevated cerebrospinal fluid neopterin and mirrored oligoclonal bands, which prompted testing for autoantibodies. VGKC-complex antibodies were elevated (201 pmol/L, normalVGKC-complex antibodies might represent a marker of immune therapy responsiveness in a subgroup of patients with infantile epileptic encephalopathy. © The Authors. Developmental Medicine & Child Neurology © 2011 Mac Keith Press.

  5. Monoclonal antibody to the type I insulin-like growth factor (IGF-I) receptor blocks IGF-I receptor-mediated DNA synthesis: clarification of the mitogenic mechanisms of IGF-I and insulin in human skin fibroblasts

    International Nuclear Information System (INIS)

    Flier, J.S.; Usher, P.; Moses, A.C.

    1986-01-01

    Insulin and insulin-like growth factor type I (IGF-I) stimulate an overlapping spectrum of biological responses in human skin fibroblasts. Although insulin and IGF-I are known to stimulate the incorporation of [ 3 H]thymidine into DNA in these cells, the identify of the receptor(s) that mediates this effect has not been fully clarified. The mouse anti-human IGF-I receptor antibody αIR-3 binds with specificity to IGF-I but not to insulin receptors in human placental membranes; it also specifically inhibits the binding of 125 I-labeled IGF-I but not 125 I-labeled insulin to suspensions of human skin fibroblasts in a dose-dependent manner. αIR-3 competitively inhibits IGF-I-mediated stimulation of [ 3 H]thymidine incorporation into DNA. This inhibition is dependent on the concentration of αIR-3 and in the presence of a fixed antibody concentration can be partially overcome by high concentrations of IGF-I. In contrast, at concentrations of 3 H]thymidine incorporation is not inhibited by αIR-3. However, the incremental effects of higher concentrations (> 1 μg/ml) of insulin on [ 3 H]thymidine incorporation are inhibited by αIR-3. αIR-3 is a highly specific antagonist of IGF-I receptor-mediated mitogenesis in human skin fibroblasts. By using this antibody, it is shown directly that insulin can act through the IGF-I receptor to stimulate DNA synthesis but can also activate this effect through the insulin receptor itself

  6. Ranitidine improves postoperative suppression of antibody response to preoperative vaccination

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørgen; Hammer, J H; Moesgaard, F

    1992-01-01

    The effect of the histamine-2 receptor antagonist ranitidine (100 mg intravenously every 12 hours for 72 hours) on postoperative serum antibody responses to preoperative immunization with six limit of flocculation tetanus toxoid and six limit of flocculation diphtheria toxoid was assessed...... in a double-blind, placebo-controlled randomized study in 26 patients undergoing major abdominal surgery. The preoperative antitetanus antibody level was less than 0.1 IU/ml in all patients, and they were inoculated with both antigens 48 hours before surgery. Serum samples for analysis of antitetanus toxoid...... and antidiphtheria toxoid were drawn before skin incision and on postoperative days 1, 3, 5, 7, 10, 14, 21, and 28. Ranitidine significantly increased the postoperative antibody response to tetanus toxoid, (p less than 0.01) and insignificantly increased that to diphtheria toxoid vaccination (p less than 0...

  7. Ly6G-mediated depletion of neutrophils is dependent on macrophages.

    Science.gov (United States)

    Bruhn, Kevin W; Dekitani, Ken; Nielsen, Travis B; Pantapalangkoor, Paul; Spellberg, Brad

    2016-01-01

    Antibody-mediated depletion of neutrophils is commonly used to study neutropenia. However, the mechanisms by which antibodies deplete neutrophils have not been well defined. We noticed that mice deficient in complement and macrophages had blunted neutrophil depletion in response to anti-Ly6G monoclonal antibody (MAb) treatment. In vitro, exposure of murine neutrophils to anti-Ly6G MAb in the presence of plasma did not result in significant depletion of cells, either in the presence or absence of complement. In vivo, anti-Ly6G-mediated neutrophil depletion was abrogated following macrophage depletion, but not complement depletion, indicating a requirement for macrophages to induce neutropenia by this method. These results inform the use and limitations of anti-Ly6G antibody as an experimental tool for depleting neutrophils in various immunological settings.

  8. Improved tumor imaging with radiolabeled monoclonal antibodies by plasma clearance with anti-antibody column

    International Nuclear Information System (INIS)

    Lear, J.L.; Kasliwal, R.; Feyerabend, A.; Bunn, P.; Dienhart, D.G.; Johnson, T.K.; Glenn, S.D.; Maddock, S.W.

    1990-01-01

    This paper reports on imaging of tumors with use of radiolabeled monoclonal antibodies (MoAs) that often hindered by high levels of background activity. The ability to lower blood pool MoA activity at a selected time after injection offers a potential method to reduce background while preserving tumor uptake. Toward this goal, the authors investigated the process of clearing MoA from patients' plasma with use of an anti-antibody column. One patient with breast cancer and four with lung cancer were given intravenous injection of 5 mCi of indium-111 KC4 (Coulter Immunology) and imaged at 20, 24, 48, and 72 hours with use of a whole-body canner coupled to a computer. Plasma clearance was performed between the 20- and 24-hour images with use of a COBEIA system. Images were inspected visually and analyzed by region-of-interest quantification

  9. Pichia pastoris-Expressed Bivalent Virus-Like Particulate Vaccine Induces Domain III-Focused Bivalent Neutralizing Antibodies without Antibody-Dependent Enhancement in Vivo

    Directory of Open Access Journals (Sweden)

    Rahul Shukla

    2018-01-01

    Full Text Available Dengue, a significant public health problem in several countries around the world, is caused by four different serotypes of mosquito-borne dengue viruses (DENV-1, -2, -3, and -4. Antibodies to any one DENV serotype which can protect against homotypic re-infection, do not offer heterotypic cross-protection. In fact, cross-reactive antibodies may augment heterotypic DENV infection through antibody-dependent enhancement (ADE. A recently launched live attenuated vaccine (LAV for dengue, which consists of a mixture of four chimeric yellow-fever/dengue vaccine viruses, may be linked to the induction of disease-enhancing antibodies. This is likely related to viral interference among the replicating viral strains, resulting in an unbalanced immune response, as well as to the fact that the LAV encodes prM, a DENV protein documented to elicit ADE-mediating antibodies. This makes it imperative to explore the feasibility of alternate ADE risk-free vaccine candidates. Our quest for a non-replicating vaccine centered on the DENV envelope (E protein which mediates virus entry into the host cell and serves as an important target of the immune response. Serotype-specific neutralizing epitopes and the host receptor recognition function map to E domain III (EDIII. Recently, we found that Pichia pastoris-expressed DENV E protein, of all four serotypes, self-assembled into virus-like particles (VLPs in the absence of prM. Significantly, these VLPs displayed EDIII and elicited EDIII-focused DENV-neutralizing antibodies in mice. We now report the creation and characterization of a novel non-replicating recombinant particulate vaccine candidate, produced by co-expressing the E proteins of DENV-1 and DENV-2 in P. pastoris. The two E proteins co-assembled into bivalent mosaic VLPs (mVLPs designated as mE1E2bv VLPs. The mVLP, which preserved the serotype-specific antigenic integrity of its two component proteins, elicited predominantly EDIII-focused homotypic virus

  10. Thermodynamics of antibody-antigen interaction revealed by mutation analysis of antibody variable regions.

    Science.gov (United States)

    Akiba, Hiroki; Tsumoto, Kouhei

    2015-07-01

    Antibodies (immunoglobulins) bind specific molecules (i.e. antigens) with high affinity and specificity. In order to understand their mechanisms of recognition, interaction analysis based on thermodynamic and kinetic parameters, as well as structure determination is crucial. In this review, we focus on mutational analysis which gives information about the role of each amino acid residue in antibody-antigen interaction. Taking anti-hen egg lysozyme antibodies and several anti-small molecule antibodies, the energetic contribution of hot-spot and non-hot-spot residues is discussed in terms of thermodynamics. Here, thermodynamics of the contribution from aromatic, charged and hydrogen bond-forming amino acids are discussed, and their different characteristics have been elucidated. The information gives fundamental understanding of the antibody-antigen interaction. Furthermore, the consequences of antibody engineering are analysed from thermodynamic viewpoints: humanization to reduce immunogenicity and rational design to improve affinity. Amino acid residues outside hot-spots in the interface play important roles in these cases, and thus thermodynamic and kinetic parameters give much information about the antigen recognition. Thermodynamic analysis of mutant antibodies thus should lead to advanced strategies to design and select antibodies with high affinity. © The Authors 2015. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

  11. Antibody therapy of cancer : Fc receptor-mediated mechanisms of action

    NARCIS (Netherlands)

    Overdijk, M.B.

    2013-01-01

    Cancer, a class of malignant diseases characterized by unregulated cell growth, is still a leading cause of death worldwide. The high specificity of antibodies combined with the ability to engage multiple mechanisms of action (MoA) and minimal side-effects makes them attractive agents for targeted

  12. Antibody neutralization of retargeted measles viruses

    Science.gov (United States)

    Lech, Patrycja J.; Pappoe, Roland; Nakamura, Takafumi; Tobin, Gregory J.; Nara, Peter L.; Russell, Stephen J.

    2014-01-01

    The measles virus (MV) vaccine lineage is a promising oncolytic but prior exposure to the measles vaccine or wild-type MV strains limits treatment utility due to the presence of anti-measles antibodies. MV entry can be redirected by displaying a polypeptide ligand on the Hemagglutinin (H) C-terminus. We hypothesized that retargeted MV would escape neutralization by monoclonal antibodies (mAbs) recognizing the H receptor-binding surface and be less susceptible to neutralization by human antisera. Using chimeric H proteins, with and without mutations that ablate MV receptor binding, we show that retargeted MVs escape mAbs that target the H receptor-binding surface by virtue of mutations that ablate infection via SLAM and CD46. However, C-terminally displayed domains do not mediate virus entry in the presence of human antibodies that bind to the underlying H domain. In conclusion, utility of retargeted oncolytic measles viruses does not extend to evasion of human serum neutralization. PMID:24725950

  13. Antibody-Dependent Cellular Cytotoxicity Activity of a Novel Anti-PD-L1 Antibody Avelumab (MSB0010718C) on Human Tumor Cells.

    Science.gov (United States)

    Boyerinas, Benjamin; Jochems, Caroline; Fantini, Massimo; Heery, Christopher R; Gulley, James L; Tsang, Kwong Yok; Schlom, Jeffrey

    2015-10-01

    Several anti-PD-1/PD-L1 monoclonal antibodies (mAb) are currently providing evidence of clinical benefit in subsets of cancer patients. The mode of action of these mAbs is to inhibit PD-1 on immune cells interacting with PD-L1 on tumor cells. These mAbs are either designed or engineered to eliminate antibody-dependent cell-mediated cytotoxicity (ADCC), which, however, has been implicated as an important mechanism in several highly effective mAb-mediated cancer therapies. A fully human anti-PD-L1 mAb would potentially be able to block PD-1/PD-L1 interactions and also mediate the ADCC lysis of tumor cells. MSB0010718C (designated avelumab) is a fully human IgG1 anti-PD-L1 mAb. The studies reported here demonstrate (i) the ability of avelumab to lyse a range of human tumor cells in the presence of PBMC or NK effectors; (ii) IFNγ can enhance tumor cell PD-L1 expression and, in some cases, enhance ADCC tumor cell lysis; (iii) purified NK cells are potent effectors for avelumab; (iv) similar levels of avelumab-mediated ADCC lysis of tumor cells are seen using purified NK as effectors from either healthy donors or cancer patients; (v) very low levels of avelumab-mediated lysis are seen using whole PBMCs as targets; this finding complements results seen in analyses of PBMC subsets of patients receiving avelumab; and (vi) the addition of IL12 to NK cells greatly enhances avelumab-mediated ADCC. These studies thus provide an additional mode of action for an anti-PD-L1 mAb and support the rationale for further studies to enhance avelumab-mediated ADCC activity. ©2015 American Association for Cancer Research.

  14. Immunity War: A Novel Therapy for Lymphoma Using T-cell Bispecific Antibodies.

    Science.gov (United States)

    Prakash, Ajay; Diefenbach, Catherine S

    2018-06-08

    The activity of T cell mediated immunotherapies in B cell lymphoma has been limited to date. The novel bi-specific antibody CD20-TCB, has a 2:1 antibody design to maximize T cell engagement, and demonstrates activity in preclinical models. This may represent a novel therapeutic approach for patients with relapsed/refractory NHL. Copyright ©2018, American Association for Cancer Research.

  15. Characterization of a Novel Humanized Anti-CD20 Antibody with Potent Anti-Tumor Activity against Non-Hodgkin's Lymphoma

    Directory of Open Access Journals (Sweden)

    Haifeng Zhang

    2013-09-01

    Full Text Available Background: Rituximab, a mouse Fab and human Fc chimeric antibody, has been widely used to treat Non-Hodgkin's lymphoma (NHL. However, only 48% of patients respond to the treatment and complete response rate is below 10%. Also, immunogenicity was reported in 17-20% patients receiving the treatment, making it unsuitable for long term diseases such as autoimmune disorders. It has been a hot research field to “humanize” rituximab toward improved efficacy and reduced immunogenicity. Methods: In this study, an advanced antibody humanization technology was applied to the sequence of the anti-CD20 antibody 2B8, its sequence of which was based on the original murine monoclonal antibody of rituximab in Roche. The complementarity-determining regions (CDRs of the humanized antibodies were further optimized through computer-aided molecular dock. Results: Five novel humanized anti-CD20 antibodies 1-5(1635, 1534, 3637, 1634 and 1536 were generated and their immunogenicity was significantly decreased when compared to rituximab. The novel humanized anti-CD20 antibodies 1-5 retained the binding activity of their murine counterpart, as demonstrated by the fluorescence-activated cell-sorting analysis (FACS. When compared to rituximab, the humanized antibodies still have the similar properties on both complement-dependent cytotoxicity (CDC and antibody-dependent cell-mediated cytotoxicity (ADCC. Furthermore, its anti-tumor efficacy in xenograft model is comparable to that of rituximab. Conclusion: The humanized anti-CD20 antibodies 1-5 have lower immunogenicity than rituximab. And at the same time, they still retain the anti-tumor effect both in vitro and vivo.

  16. Generation of chimeric bispecific G250/anti-CD3 monoclonal antibody, a tool to combat renal cell carcinoma

    NARCIS (Netherlands)

    Luiten, R. M.; Coney, L. R.; Fleuren, G. J.; Warnaar, S. O.; Litvinov, S. V.

    1996-01-01

    The monoclonal antibody (MAb) G250 binds to a tumour-associated antigen, expressed in renal cell carcinoma (RCC), which has been demonstrated to be a suitable target for antibody-mediated immunotherapy. A bispecific antibody having both G250 and anti-CD3 specificity can cross-link G250

  17. Non-Neutralizing Antibodies Directed against HIV and Their Functions

    Directory of Open Access Journals (Sweden)

    Luzia M. Mayr

    2017-11-01

    Full Text Available B cells produce a plethora of anti-HIV antibodies (Abs but only few of them exhibit neutralizing activity. This was long considered a profound limitation for the enforcement of humoral immune responses against HIV-1 infection, especially since these neutralizing Abs (nAbs are extremely difficult to induce. However, increasing evidence shows that additional non-neutralizing Abs play a significant role in decreasing the viral load, leading to partial and sometimes even total protection. Mechanisms suspected to participate in protection are numerous. They involve the Fc domain of Abs as well as their Fab part, and consequently the induced Ab isotype will be determinant for their functions, as well as the quantity and quality of the Fc-receptors (FcRs expressed on immune cells. Fc-mediated inhibitory functions, such as Ab-dependent cellular cytotoxicity, antibody-dependent cellular phagocytosis, aggregation, and even immune activation have been proposed. However, as for nAbs, the non-neutralizing activities are limited to a subset of anti-HIV Abs. An improved in-depth characterization of the Abs displaying these functional responses is required for the development of new vaccination strategies, which aim to selectively trigger the B cells able to induce the right functional Ab combinations both at the right place and at the right time. This review summarizes our current knowledge on non-neutralizing functional inhibitory Abs and discusses the potential benefit of inducing them via vaccination. We also provide new insight into the roles of the FcγR-mediated Ab therapeutics in clinical trials for HIV diseases.

  18. Strong antitumor activities of IgG3 antibodies to a human melanoma-associated ganglioside

    International Nuclear Information System (INIS)

    Hellstroem, I.; Brankovan, V.; Hellstroem, K.E.

    1985-01-01

    Three mouse monoclonal IgG3 antibodies, 2B2, IF4, and MG-21, recognize a G/sub D3/ ganglioside antigen that is expressed at the cell surface of most human melanomas. All three antibodies mediate antibody-dependent cellular cytotoxicity (ADCC) in vitro when tested with human lymphocytes or effector cells in a 2-hr or 4-hr 51 Cr-release test, and one antibody, MG-21, also gives strong complement-dependent cytotoxicity with human serum. Antibody 2B2, which gives ADDC also in the presence of mouse lymphocytes, inhibited the outgrowth of a human melanoma in nude mice, but antibody IF4, which showed no ADCC with mouse lymphocyte effectors, did not

  19. Bispecific antibodies and their use in applied research

    Directory of Open Access Journals (Sweden)

    Harshit Verma

    Full Text Available Bispecific antibodies (BsAb can, by virtue of combining two binding specificities, improve the selectivity and efficacy of antibody-based treatment of human disease. Antibodies with two distinct binding specificities have great potential for a wide range of clinical applications as targeting agents for in vitro and in vivo immunodiagnosis, therapy and for improving immunoassays. They have shown great promise for targeting cytotoxic effector cells, delivering radionuclides, toxins or cytotoxic drugs to specific targets, particularly tumour cells. The development of BsAb research goes through three main stages: chemical cross linking of murine-derived monoclonal antibody, hybrid hybridomas and engineered BsAb. This article is providing the potential applications of bispecific antibodies. [Vet World 2012; 5(12.000: 775-780

  20. Paraneoplastic limbic encephalitis in a patient with extragonadal choriocarcinoma--significance of onconeural antibodies.

    Science.gov (United States)

    Szkandera, Joanna; Ploner, Ferdin; Bauernhofer, Thomas; Kasparek, Anne-Katrin; Payer, Franz; Balic, Marija; Knechtel, Gudrun; Gerger, Armin; Gallè, Günter; Samonigg, Hellmut; Hofmann, Günter

    2010-01-01

    Paraneoplastic limbic or brainstem encephalitis is considered to be an autoimmune-mediated disorder of the nervous system associated with different types of cancer including germ cell tumors. We report on a 31-year-old patient presenting with eye motility dysfunction, dysarthrophonia, lethargy, depression, slow mentation, disorientation, dysgraphia, and retarded motion sequence. Neurologic tests, brain imaging, and blood chemistry tests failed to determine the cause of the symptoms. Further examinations including ultrasound of the abdomen led to the detection of a retroperitoneal mass. The biopsy of this mass showed fractions of a choriocarcinoma. The patient underwent curative chemotherapy, but although the cancer therapy was successful, the neurologic disorders did not improve. Concurrent examination for anti-Ma2 antibodies in the serum was positive and confirmed the paraneoplastic origin of these symptoms. Patients with symptoms of limbic or brainstem encephalitis, especially young men, should be tested for anti-Ma2 antibodies in the serum to elucidate their origin. The detection of these antibodies supports the diagnosis of a paraneoplastic syndrome, and may lead to the earlier identification of an otherwise hidden extragonadal germ cell tumor. Copyright © 2010 S. Karger AG, Basel.

  1. Human oxidation-specific antibodies reduce foam cell formation and atherosclerosis progression

    DEFF Research Database (Denmark)

    Tsimikas, Sotirios; Miyanohara, Atsushi; Hartvigsen, Karsten

    2011-01-01

    We sought to assess the in vivo importance of scavenger receptor (SR)-mediated uptake of oxidized low-density lipoprotein (OxLDL) in atherogenesis and to test the efficacy of human antibody IK17-Fab or IK17 single-chain Fv fragment (IK17-scFv), which lacks immunologic properties of intact antibod...... antibodies other than the ability to inhibit uptake of OxLDL by macrophages, to inhibit atherosclerosis....

  2. Cooperativity between CD8+ T cells, non-neutralizing antibodies, and alveolar macrophages is important for heterosubtypic influenza virus immunity.

    Directory of Open Access Journals (Sweden)

    Brian J Laidlaw

    2013-03-01

    Full Text Available Seasonal epidemics of influenza virus result in ∼36,000 deaths annually in the United States. Current vaccines against influenza virus elicit an antibody response specific for the envelope glycoproteins. However, high mutation rates result in the emergence of new viral serotypes, which elude neutralization by preexisting antibodies. T lymphocytes have been reported to be capable of mediating heterosubtypic protection through recognition of internal, more conserved, influenza virus proteins. Here, we demonstrate using a recombinant influenza virus expressing the LCMV GP33-41 epitope that influenza virus-specific CD8+ T cells and virus-specific non-neutralizing antibodies each are relatively ineffective at conferring heterosubtypic protective immunity alone. However, when combined virus-specific CD8 T cells and non-neutralizing antibodies cooperatively elicit robust protective immunity. This synergistic improvement in protective immunity is dependent, at least in part, on alveolar macrophages and/or other lung phagocytes. Overall, our studies suggest that an influenza vaccine capable of eliciting both CD8+ T cells and antibodies specific for highly conserved influenza proteins may be able to provide heterosubtypic protection in humans, and act as the basis for a potential "universal" vaccine.

  3. Rare Association of Anti-Hu Antibody Positive Paraneoplastic Neurological Syndrome and Transitional Cell Bladder Carcinoma

    Directory of Open Access Journals (Sweden)

    S. Lukacs

    2012-01-01

    Full Text Available Introduction. Paraneoplastic encephalomyelitis (PEM and subacute sensory neuronopathy (SSN are remote effects of cancer, usually associated with small-cell lung carcinoma and positive anti-Hu antibody. We describe the rare association of bladder transitional cell carcinoma (TCC with anti-Hu antibody positivity resulting in this paraneoplastic neurological syndrome. Patient. A 76-year-old female presented with bilateral muscle weakness and paraesthesia of the upper and lower limbs in a length-dependent “glove and stocking” distribution. Central nervous system symptoms included cognitive problems, personality change, and truncal ataxia. Case notes and the literature were reviewed. Result. Autoantibody screening was positive for anti-Hu antibody (recently renamed antineuronal nuclear antibody 1, ANNA-1. The diagnosis of PEM and SSN was supported by MRI and lumbar puncture results. A superficial bladder TCC was demonstrated on CT and subsequently confirmed on histology. No other primary neoplasm was found on full-body imaging. The neurological symptoms were considered to be an antibody-mediated paraneoplastic neurological syndrome and improved after resection of the tumour. Discussion. The association of anti-Hu positive paraneoplastic neurological syndrome and TCC has not been described in the literature previously. We emphasize the need for detailed clinical examination and the importance of a multidisciplinary thought process and encourage further awareness of this rare association.

  4. A novel merozoite surface antigen of Plasmodium falciparum (MSP-3 identified by cellular-antibody cooperative mechanism antigenicity and biological activity of antibodies

    Directory of Open Access Journals (Sweden)

    Claude Oeuvray

    1994-01-01

    Full Text Available We report the identification of a 48kDa antigen targeted by antibodies which inhibit Plasmodium falciparum in vitro growth by cooperation with blood monocytes in an ADCI assay correlated to the naturally acquired protection. This protein is located on the surface of the merozoite stage of P. falciparum, and is detectable in all isolates tested. Epidemiological studies demonstrated that peptides derived from the amino acid sequence of MSP-3 contain potent B and T-cell epitopes recognized by a majority of individuals living in endemic areas. Moreover human antibodies either purified on the recombinant protein, or on the synthetic peptide MSP-3b, as well as antibodies raised in mice, were all found to promote parasite killing mediated by monocytes.

  5. The effect of daily co-trimoxazole prophylaxis on natural development of antibody-mediated immunity against P. falciparum malaria infection in HIV-exposed uninfected Malawian children.

    Directory of Open Access Journals (Sweden)

    Herbert Longwe

    Full Text Available Co-trimoxazole prophylaxis, currently recommended in HIV-exposed, uninfected (HEU children as protection against opportunistic infections, also has some anti-malarial efficacy. We determined whether daily co-trimoxazole prophylaxis affects the natural development of antibody-mediated immunity to blood-stage Plasmodium falciparum malaria infection.Using an enzyme-linked immunosorbent assay, we measured antibodies to 8 Plasmodium falciparum antigens (AMA-1, MSP-119, MSP-3, PfSE, EBA-175RII, GLURP R0, GLURP R2 and CSP in serum samples from 33 HEU children and 31 HIV-unexposed, uninfected (HUU children, collected at 6, 12 and 18 months of age.Compared to HIV-uninfected children, HEU children had significantly lower levels of specific IgG against AMA-1 at 6 months (p = 0.001, MSP-119 at 12 months (p = 0.041 and PfSE at 6 months (p = 0.038, 12 months (p = 0.0012 and 18 months (p = 0.0097. No differences in the IgG antibody responses against the rest of the antigens were observed between the two groups at all time points. The breadth of specificity of IgG response was reduced in HEU children compared to HUU children during the follow up period.Co-trimoxazole prophylaxis seems to reduce IgG antibody responses to P. falciparum blood stage antigens, which could be as a result of a reduction in exposure of those children under this regime. Although antibody responses were regarded as markers of exposure in this study, further studies are required to establish whether these responses are correlated in any way to clinical immunity to malaria.

  6. Improvement of Agrobacterium-mediated transformation and rooting of black cherry

    Science.gov (United States)

    Ying Wang; Paula M. Pijut

    2014-01-01

    An improved protocol for Agrobacterium-mediated transformation of an elite, mature black cherry genotype was developed. To increase transformation efficiency, vacuum infiltration, sonication, and a combination of the two treatments were applied during the cocultivation of leaf explants with Agrobacterium tumefaciens strain EHA105...

  7. High avidity antibodies to full-length VAR2CSA correlate with absence of placental malaria

    DEFF Research Database (Denmark)

    Tutterrow, Yeung Lo; Salanti, Ali; Avril, Marion

    2012-01-01

    VAR2CSA mediates sequestration of Plasmodium falciparum-infected erythrocytes in the placenta, increasing the risk of poor pregnancy outcomes. Naturally acquired antibodies (Ab) to placental parasites at delivery have been associated with improved pregnancy outcomes, but Ab levels and how early...... in pregnancy Ab must be present in order to eliminate placental parasites before delivery remains unknown. Antibodies to individual Duffy-binding like domains of VAR2CSA have been studied, but the domains lack many of the conformational epitopes present in full-length VAR2CSA (FV2). Thus, the purpose...... of this study was to describe the acquisition of Ab to FV2 in women residing in high and low transmission areas and determine how Ab levels during pregnancy correlate with clearance of placental parasites. Plasma samples collected monthly throughout pregnancy from pregnant women living in high and low...

  8. Relevance of MICA and other non-HLA antibodies in clinical transplantation.

    Science.gov (United States)

    Sumitran-Holgersson, Suchitra

    2008-10-01

    The clinical importance of HLA-specific antibodies for organ allograft outcome is well established. In the past few years, there has been an increasing interest in non-HLA antigens as targets of injury in organ transplant recipients. This increased interest has been spurred by the fact that HLA-identical kidney transplants also undergo immunological rejections. Polymorphisms within non-HLA genes associated with evoking an immune response to alloantigens are currently being studied for their association with transplant outcome. Non-HLA antigens, such as the polymorphic MHC class I-related chain A (MICA), expressed on endothelial cells have been implicated in the pathogenesis of hyperacute, acute and chronic organ allograft rejections. Use of endothelial cells as targets may clarify the specificities of other clinically relevant non-HLA antibodies in graft rejections. This review summarizes past and current knowledge of the clinical importance and specificities of non-HLA antibodies, and mechanisms by which these antibodies may contribute to graft destruction in clinical transplantation. The aims of current research into the role of non-HLA antigens and their genetics in predicting outcome are to develop an improved insight into the basic science of transplantation and to develop a risk or prognostic index for use in the clinical setting. Non-HLA antibody responses are receiving increasing interest in acute and chronic rejection and specificity, affinity, and pathogenicity need to be investigated to estimate their contribution. Undoubtedly, this will continue to be an area of interest in terms of fully understanding the role of non-HLA antigens as targets of immune-mediated injury and the potential for clinical intervention.

  9. Boosting antibody developability through rational sequence optimization.

    Science.gov (United States)

    Seeliger, Daniel; Schulz, Patrick; Litzenburger, Tobias; Spitz, Julia; Hoerer, Stefan; Blech, Michaela; Enenkel, Barbara; Studts, Joey M; Garidel, Patrick; Karow, Anne R

    2015-01-01

    The application of monoclonal antibodies as commercial therapeutics poses substantial demands on stability and properties of an antibody. Therapeutic molecules that exhibit favorable properties increase the success rate in development. However, it is not yet fully understood how the protein sequences of an antibody translates into favorable in vitro molecule properties. In this work, computational design strategies based on heuristic sequence analysis were used to systematically modify an antibody that exhibited a tendency to precipitation in vitro. The resulting series of closely related antibodies showed improved stability as assessed by biophysical methods and long-term stability experiments. As a notable observation, expression levels also improved in comparison with the wild-type candidate. The methods employed to optimize the protein sequences, as well as the biophysical data used to determine the effect on stability under conditions commonly used in the formulation of therapeutic proteins, are described. Together, the experimental and computational data led to consistent conclusions regarding the effect of the introduced mutations. Our approach exemplifies how computational methods can be used to guide antibody optimization for increased stability.

  10. Molluskan Hemocyanins Activate the Classical Pathway of the Human Complement System through Natural Antibodies.

    Science.gov (United States)

    Pizarro-Bauerle, Javier; Maldonado, Ismael; Sosoniuk-Roche, Eduardo; Vallejos, Gerardo; López, Mercedes N; Salazar-Onfray, Flavio; Aguilar-Guzmán, Lorena; Valck, Carolina; Ferreira, Arturo; Becker, María Inés

    2017-01-01

    Molluskan hemocyanins are enormous oxygen-carrier glycoproteins that show remarkable immunostimulatory properties when inoculated in mammals, such as the generation of high levels of antibodies, a strong cellular reaction, and generation of non-specific antitumor immune responses in some types of cancer, particularly for superficial bladder cancer. These proteins have the ability to bias the immune response toward a T h 1 phenotype. However, despite all their current uses with beneficial clinical outcomes, a clear mechanism explaining these properties is not available. Taking into account reports of natural antibodies against the hemocyanin of the gastropod Megathura crenulata [keyhole limpet hemocyanin (KLH)] in humans as well as other vertebrate species, we report here for the first time, the presence, in sera from unimmunized healthy donors, of antibodies recognizing, in addition to KLH, two other hemocyanins from gastropods with documented immunomodulatory capacities: Fisurella latimarginata hemocyanin (FLH) and Concholepas concholepas hemocyanin (CCH). Through an ELISA screening, we found IgM and IgG antibodies reactive with these hemocyanins. When the capacity of these antibodies to bind deglycosylated hemocyanins was studied, no decreased interaction was detected. Moreover, in the case of FLH, deglycosylation increased antibody binding. We evaluated through an in vitro complement deposition assay whether these antibodies activated the classical pathway of the human complement system. The results showed that all three hemocyanins and their deglycosylated counterparts elicited this activation, mediated by C1 binding to immunoglobulins. Thus, this work contributes to the understanding on how the complement system could participate in the immunostimulatory properties of hemocyanins, through natural, complement-activating antibodies reacting with these proteins. Although a role for carbohydrates cannot be completely ruled out, in our experimental setting

  11. Resistance of Subtype C HIV-1 Strains to Anti-V3 Loop Antibodies

    Directory of Open Access Journals (Sweden)

    David Almond

    2012-01-01

    Full Text Available HIV-1’s subtype C V3 loop consensus sequence exhibits increased resistance to anti-V3 antibody-mediated neutralization as compared to the subtype B consensus sequence. The dynamic 3D structure of the consensus C V3 loop crown, visualized by ab initio folding, suggested that the resistance derives from structural rigidity and non-β-strand secondary protein structure in the N-terminal strand of the β-hairpin of the V3 loop crown, which is where most known anti-V3 loop antibodies bind. The observation of either rigidity or non-β-strand structure in this region correlated with observed resistance to antibody-mediated neutralization in a series of chimeric pseudovirus (psV mutants. The results suggest the presence of an epitope-independent, neutralization-relevant structural difference in the antibody-targeted region of the V3 loop crown between subtype C and subtype B, a difference that we hypothesize may contribute to the divergent pattern of global spread between these subtypes. As antibodies to a variable loop were recently identified as an inverse correlate of risk for HIV infection, the structure-function relationships discussed in this study may have relevance to HIV vaccine research.

  12. Differential Killing of Salmonella enterica Serovar Typhi by Antibodies Targeting Vi and Lipopolysaccharide O:9 Antigen.

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    Peter J Hart

    Full Text Available Salmonella enterica serovar Typhi expresses a capsule of Vi polysaccharide, while most Salmonella serovars, including S. Enteritidis and S. Typhimurium, do not. Both S. Typhi and S. Enteritidis express the lipopolysaccharide O:9 antigen, yet there is little evidence of cross-protection from anti-O:9 antibodies. Vaccines based on Vi polysaccharide have efficacy against typhoid fever, indicating that antibodies against Vi confer protection. Here we investigate the role of Vi capsule and antibodies against Vi and O:9 in antibody-dependent complement- and phagocyte-mediated killing of Salmonella. Using isogenic Vi-expressing and non-Vi-expressing derivatives of S. Typhi and S. Typhimurium, we show that S. Typhi is inherently more sensitive to serum and blood than S. Typhimurium. Vi expression confers increased resistance to both complement- and phagocyte-mediated modalities of antibody-dependent killing in human blood. The Vi capsule is associated with reduced C3 and C5b-9 deposition, and decreased overall antibody binding to S. Typhi. However, purified human anti-Vi antibodies in the presence of complement are able to kill Vi-expressing Salmonella, while killing by anti-O:9 antibodies is inversely related to Vi expression. Human serum depleted of antibodies to antigens other than Vi retains the ability to kill Vi-expressing bacteria. Our findings support a protective role for Vi capsule in preventing complement and phagocyte killing of Salmonella that can be overcome by specific anti-Vi antibodies, but only to a limited extent by anti-O:9 antibodies.

  13. Differential Killing of Salmonella enterica Serovar Typhi by Antibodies Targeting Vi and Lipopolysaccharide O:9 Antigen.

    Science.gov (United States)

    Hart, Peter J; O'Shaughnessy, Colette M; Siggins, Matthew K; Bobat, Saeeda; Kingsley, Robert A; Goulding, David A; Crump, John A; Reyburn, Hugh; Micoli, Francesca; Dougan, Gordon; Cunningham, Adam F; MacLennan, Calman A

    2016-01-01

    Salmonella enterica serovar Typhi expresses a capsule of Vi polysaccharide, while most Salmonella serovars, including S. Enteritidis and S. Typhimurium, do not. Both S. Typhi and S. Enteritidis express the lipopolysaccharide O:9 antigen, yet there is little evidence of cross-protection from anti-O:9 antibodies. Vaccines based on Vi polysaccharide have efficacy against typhoid fever, indicating that antibodies against Vi confer protection. Here we investigate the role of Vi capsule and antibodies against Vi and O:9 in antibody-dependent complement- and phagocyte-mediated killing of Salmonella. Using isogenic Vi-expressing and non-Vi-expressing derivatives of S. Typhi and S. Typhimurium, we show that S. Typhi is inherently more sensitive to serum and blood than S. Typhimurium. Vi expression confers increased resistance to both complement- and phagocyte-mediated modalities of antibody-dependent killing in human blood. The Vi capsule is associated with reduced C3 and C5b-9 deposition, and decreased overall antibody binding to S. Typhi. However, purified human anti-Vi antibodies in the presence of complement are able to kill Vi-expressing Salmonella, while killing by anti-O:9 antibodies is inversely related to Vi expression. Human serum depleted of antibodies to antigens other than Vi retains the ability to kill Vi-expressing bacteria. Our findings support a protective role for Vi capsule in preventing complement and phagocyte killing of Salmonella that can be overcome by specific anti-Vi antibodies, but only to a limited extent by anti-O:9 antibodies.

  14. Malachite green mediates homodimerization of antibody VL domains to form a fluorescent ternary complex with singular symmetric interfaces

    Science.gov (United States)

    Szent-Gyorgyi, Chris; Stanfield, Robyn L.; Andreko, Susan; Dempsey, Alison; Ahmed, Mushtaq; Capek, Sara; Waggoner, Alan; Wilson, Ian A.; Bruchez, Marcel P.

    2013-01-01

    We report that a symmetric small molecule ligand mediates the assembly of antibody light chain variable domains (VLs) into a correspondent symmetric ternary complex with novel interfaces. The L5* Fluorogen Activating Protein (FAP) is a VL domain that binds malachite green dye (MG) to activate intense fluorescence. Crystallography of liganded L5* reveals a 2:1 protein:ligand complex with inclusive C2 symmetry, where MG is almost entirely encapsulated between an antiparallel arrangement of the two VL domains. Unliganded L5* VL domains crystallize as a similar antiparallel VL/VL homodimer. The complementarity determining regions (CDRs) are spatially oriented to form novel VL/VL and VL/ligand interfaces that tightly constrain a propeller conformer of MG. Binding equilibrium analysis suggests highly cooperative assembly to form a very stable VL/MG/VL complex, such that MG behaves as a strong chemical inducer of dimerization. Fusion of two VL domains into a single protein tightens MG binding over 1,000-fold to low picomolar affinity without altering the large binding enthalpy, suggesting that bonding interactions with ligand and restriction of domain movements make independent contributions to binding. Fluorescence activation of a symmetrical fluorogen provides a selection mechanism for the isolation and directed evolution of ternary complexes where unnatural symmetric binding interfaces are favored over canonical antibody interfaces. As exemplified by L5*, these self-reporting complexes may be useful as modulators of protein association or as high affinity protein tags and capture reagents. PMID:23978698

  15. Unravelling the role of allo-antibodies and Transplant Injury

    OpenAIRE

    Yoshiko Matsuda; Minnie M Sarwal

    2016-01-01

    Alloimmunity driving rejection in the context of solid organ transplantation can be grossly divided into mechanisms predominantly driven by either T cell-mediated rejection (TCMR) or antibody-mediated rejection (ABMR), though the co-existence of both types of rejections can be seen in a variable number of sampled grafts. Acute TCMR can generally be well controlled by the establishment of effective immunosuppression 1, 2. Acute ABMR is a low frequency finding in the current era of blood group ...

  16. Hybridization-based antibody cDNA recovery for the production of recombinant antibodies identified by repertoire sequencing.

    Science.gov (United States)

    Valdés-Alemán, Javier; Téllez-Sosa, Juan; Ovilla-Muñoz, Marbella; Godoy-Lozano, Elizabeth; Velázquez-Ramírez, Daniel; Valdovinos-Torres, Humberto; Gómez-Barreto, Rosa E; Martinez-Barnetche, Jesús

    2014-01-01

    High-throughput sequencing of the antibody repertoire is enabling a thorough analysis of B cell diversity and clonal selection, which may improve the novel antibody discovery process. Theoretically, an adequate bioinformatic analysis could allow identification of candidate antigen-specific antibodies, requiring their recombinant production for experimental validation of their specificity. Gene synthesis is commonly used for the generation of recombinant antibodies identified in silico. Novel strategies that bypass gene synthesis could offer more accessible antibody identification and validation alternatives. We developed a hybridization-based recovery strategy that targets the complementarity-determining region 3 (CDRH3) for the enrichment of cDNA of candidate antigen-specific antibody sequences. Ten clonal groups of interest were identified through bioinformatic analysis of the heavy chain antibody repertoire of mice immunized with hen egg white lysozyme (HEL). cDNA from eight of the targeted clonal groups was recovered efficiently, leading to the generation of recombinant antibodies. One representative heavy chain sequence from each clonal group recovered was paired with previously reported anti-HEL light chains to generate full antibodies, later tested for HEL-binding capacity. The recovery process proposed represents a simple and scalable molecular strategy that could enhance antibody identification and specificity assessment, enabling a more cost-efficient generation of recombinant antibodies.

  17. Thermodynamic Mechanism for the Evasion of Antibody Neutralization in Flaviviruses

    Science.gov (United States)

    2015-01-01

    Mutations in the epitopes of antigenic proteins can confer viral resistance to antibody-mediated neutralization. However, the fundamental properties that characterize epitope residues and how mutations affect antibody binding to alter virus susceptibility to neutralization remain largely unknown. To address these questions, we used an ensemble-based algorithm to characterize the effects of mutations on the thermodynamics of protein conformational fluctuations. We applied this method to the envelope protein domain III (ED3) of two medically important flaviviruses: West Nile and dengue 2. We determined an intimate relationship between the susceptibility of a residue to thermodynamic perturbations and epitope location. This relationship allows the successful identification of the primary epitopes in each ED3, despite their high sequence and structural similarity. Mutations that allow the ED3 to evade detection by the antibody either increase or decrease conformational fluctuations of the epitopes through local effects or long-range interactions. Spatially distant interactions originate in the redistribution of conformations of the ED3 ensembles, not through a mechanically connected array of contiguous amino acids. These results reconcile previous observations of evasion of neutralization by mutations at a distance from the epitopes. Finally, we established a quantitative correlation between subtle changes in the conformational fluctuations of the epitope and large defects in antibody binding affinity. This correlation suggests that mutations that allow viral growth, while reducing neutralization, do not generate significant structural changes and underscores the importance of protein fluctuations and long-range interactions in the mechanism of antibody-mediated neutralization resistance. PMID:24950171

  18. Ovarian carcinoma glyco-antigen targeted by human IgM antibody.

    Directory of Open Access Journals (Sweden)

    Yi Chen

    Full Text Available Epithelial Ovarian Cancer (EOC cells expression of a novel carbohydrate antigen was defined using a human VH4-34 encoded IgM monoclonal antibody (mAb216. MAb216 binds to a poly N-acetyllactosamine epitope expressed on B cells and kills normal and malignant B cells in vitro and in vivo. EOC patient ascites and EOC cell lines were used to study the anti tumor effect of mAb216. Various assays were used to characterize the epitope and demonstrate antibody-mediated binding and cytotoxicity in EOC. Drug and antibody combination effects were determined by calculating the combination index values using the Chou and Talalay method. MAb216 displays direct antibody mediated cytotoxicity on a population of human EOC tumor and ascites samples and EOC cell lines, which express high amounts of poly N-acetyllactosamine epitope, carried by CD147/CD98. Eighty four percent of patient samples, including platin resistant, had a tumor population that bound the monoclonal antibody. The binding pattern of mAb216 and mechanism of cytotoxicity was similar to that seen on normal and malignant B cells with unique general membrane disruption and "pore" formation. In vitro incubation with mAb216 and cisplatin enhanced killing of OVCAR3 cell line. In EOC cell lines percent cytotoxicity correlated with percent expression of epitope. Although in vitro data shows specific EOC cytotoxicity, for possible treatment of EOC MAb216 would need to be evaluated in a clinical trial with or without chemotherapy.

  19. Peripheral neuropathies associated with antibodies directed to intracellular neural antigens.

    Science.gov (United States)

    Antoine, J-C

    2014-10-01

    Antibodies directed to intracellular neural antigens have been mainly described in paraneoplastic peripheral neuropathies and mostly includes anti-Hu and anti-CV2/CRMP5 antibodies. These antibodies occur with different patterns of neuropathy. With anti-Hu antibody, the most frequent manifestation is sensory neuronopathy with frequent autonomic involvement. With anti-CV2/CRMP5 the neuropathy is more frequently sensory and motor with an axonal or mixed demyelinating and axonal electrophysiological pattern. The clinical pattern of these neuropathies is in keeping with the cellular distribution of HuD and CRMP5 in the peripheral nervous system. Although present in high titer, these antibodies are probably not directly responsible for the neuropathy. Pathological and experimental studies indicate that cytotoxic T-cells are probably the main effectors of the immune response. These disorders contrast with those in which antibodies recognize a cell surface antigen and are probably responsible for the disease. The neuronal cell death and axonal degeneration which result from T-cell mediated immunity explains why treating these disorders remains challenging. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  20. Solid phase double-antibody radioimmunoassay procedure

    International Nuclear Information System (INIS)

    Niswender, G.D.

    1977-01-01

    The present invention is concerned with the radioimmunoassay (RIA) procedure for assaying body fluid content of an antigenic substance which may either be an antigen itself or a hapten capable of being converted, such as by means of reaction with a protein, to an antigenic material. The present invention is concerned with a novel and improved modification of a double-antibody RIA technique in which there is a first antibody that is specific to the antigenic substance suspected to be present in a body fluid from which the assay is intended. The second antibody, however, is not specific to the antigenic substance or analyte, but is an antibody against the first antibody

  1. Modification of Antibody Function by Mutagenesis.

    Science.gov (United States)

    Dasch, James R; Dasch, Amy L

    2017-09-01

    The ability to "fine-tune" recombinant antibodies by mutagenesis separates recombinant antibodies from hybridoma-derived antibodies because the latter are locked with respect to their properties. Recombinant antibodies can be modified to suit the application: Changes in isotype, format (e.g., scFv, Fab, bispecific antibodies), and specificity can be made once the heavy- and light-chain sequences are available. After immunoglobulin heavy and light chains for a particular antibody have been cloned, the binding site-namely, the complementarity determining regions (CDR)-can be manipulated by mutagenesis to obtain antibody variants with improved properties. The method described here is relatively simple, uses commercially available reagents, and is effective. Using the pComb3H vector, a commercial mutagenesis kit, PfuTurbo polymerase (Agilent), and two mutagenic primers, a library of phage with mutagenized heavy and light CDR3 can be obtained. © 2017 Cold Spring Harbor Laboratory Press.

  2. Primary sleep disorders can cause long-term sleep disturbance in patients with autoimmune mediated limbic encephalitis.

    Science.gov (United States)

    Anderson, Kirstie N; Kelly, Thomas P; Griffiths, Timothy D

    2013-07-01

    Antibody mediated limbic encephalitis causes a sub acute encephalopathy with an amnestic syndrome, seizures and often an affective prodrome. Sleep disturbance including abnormal dream sleep and insomnia are described in a percentage of long-term survivors but there are very few detailed assessments of sleep disturbance in patients beyond the acute phase of illness. The objectives of this study were to understand the causes of sleep disturbance in the long-term survivors of antibody mediated limbic encephalitis. We screened twelve patients under long-term follow up with sleep questionnaires and went on to perform detailed sleep studies (polysomnography) in those who reported sleep disturbance. Two were found to have persistent, severe central and obstructive sleep apnoea and two others to have restless legs and periodic limb movements of sleep. This highlights the need to investigate sleep disturbance in this group of patients. Effective treatments may be available to improve quality of life and daytime function. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Fiber-optic microsphere-based antibody array for the analysis of inflammatory cytokines in saliva.

    Science.gov (United States)

    Blicharz, Timothy M; Siqueira, Walter L; Helmerhorst, Eva J; Oppenheim, Frank G; Wexler, Philip J; Little, Frédéric F; Walt, David R

    2009-03-15

    Antibody microarrays have emerged as useful tools for high-throughput protein analysis and candidate biomarker screening. We describe here the development of a multiplexed microsphere-based antibody array capable of simultaneously measuring 10 inflammatory protein mediators. Cytokine-capture microspheres were fabricated by covalently coupling monoclonal antibodies specific for cytokines of interest to fluorescently encoded 3.1 microm polymer microspheres. An optical fiber bundle containing approximately 50,000 individual 3.1 microm diameter fibers was chemically etched to create microwells in which cytokine-capture microspheres could be deposited. Microspheres were randomly distributed in the wells to produce an antibody array for performing a multiplexed sandwich immunoassay. The array responded specifically to recombinant cytokine solutions in a concentration-dependent fashion. The array was also used to examine endogenous mediator patterns in saliva supernatants from patients with pulmonary inflammatory diseases such as asthma and chronic obstructive pulmonary disease (COPD). This array technology may prove useful as a laboratory-based platform for inflammatory disease research and diagnostics, and its small footprint could also enable integration into a microfluidic cassette for use in point-of-care testing.

  4. Basis and Statistical Design of the Passive HIV-1 Antibody Mediated Prevention (AMP) Test-of-Concept Efficacy Trials.

    Science.gov (United States)

    Gilbert, Peter B; Juraska, Michal; deCamp, Allan C; Karuna, Shelly; Edupuganti, Srilatha; Mgodi, Nyaradzo; Donnell, Deborah J; Bentley, Carter; Sista, Nirupama; Andrew, Philip; Isaacs, Abby; Huang, Yunda; Zhang, Lily; Capparelli, Edmund; Kochar, Nidhi; Wang, Jing; Eshleman, Susan H; Mayer, Kenneth H; Magaret, Craig A; Hural, John; Kublin, James G; Gray, Glenda; Montefiori, David C; Gomez, Margarita M; Burns, David N; McElrath, Julie; Ledgerwood, Julie; Graham, Barney S; Mascola, John R; Cohen, Myron; Corey, Lawrence

    2017-01-01

    Anti-HIV-1 broadly neutralizing antibodies (bnAbs) have been developed as potential agents for prevention of HIV-1 infection. The HIV Vaccine Trials Network and the HIV Prevention Trials Network are conducting the Antibody Mediated Prevention (AMP) trials to assess whether, and how, intravenous infusion of the anti-CD4 binding site bnAb, VRC01, prevents HIV-1 infection. These are the first test-of-concept studies to assess HIV-1 bnAb prevention efficacy in humans. The AMP trials are two parallel phase 2b HIV-1 prevention efficacy trials conducted in two cohorts: 2700 HIV-uninfected men and transgender persons who have sex with men in the United States, Peru, Brazil, and Switzerland; and 1500 HIV-uninfected sexually active women in seven countries in sub-Saharan Africa. Participants are randomized 1:1:1 to receive an intravenous infusion of 10 mg/kg VRC01, 30 mg/kg VRC01, or a control preparation every 8 weeks for a total of 10 infusions. Each trial is designed (1) to assess overall prevention efficacy (PE) pooled over the two VRC01 dose groups vs. control and (2) to assess VRC01 dose and laboratory markers as correlates of protection (CoPs) against overall and genotype- and phenotype-specific infection. Each AMP trial is designed to have 90% power to detect PE > 0% if PE is ≥ 60%. The AMP trials are also designed to identify VRC01 properties (i.e., concentration and effector functions) that correlate with protection and to provide insight into mechanistic CoPs. CoPs are assessed using data from breakthrough HIV-1 infections, including genetic sequences and sensitivities to VRC01-mediated neutralization and Fc effector functions. The AMP trials test whether VRC01 can prevent HIV-1 infection in two study populations. If affirmative, they will provide information for estimating the optimal dosage of VRC01 (or subsequent derivatives) and identify threshold levels of neutralization and Fc effector functions associated with high-level protection, setting a benchmark

  5. A Novel Phenolic Compound, Chloroxynil, Improves Agrobacterium-Mediated Transient Transformation in Lotus japonicus.

    Science.gov (United States)

    Kimura, Mitsuhiro; Cutler, Sean; Isobe, Sachiko

    2015-01-01

    Agrobacterium-mediated transformation is a commonly used method for plant genetic engineering. However, the limitations of Agrobacterium host-plant interactions and the complexity of plant tissue culture often make the production of transgenic plants difficult. Transformation efficiency in many legume species, including soybean and the common bean, has been reported to be quite low. To improve the transformation procedure in legumes, we screened for chemicals that increase the transformation efficiency of Lotus japonicus, a model legume species. A Chemical library was screened and chemicals that increase in transient transformation efficiency of L. japonicus accession, Miyakojima MG-20 were identified. The transient transformation efficiency was quantified by reporter activity in which an intron-containing reporter gene produces the GUS protein only when the T-DNA is expressed in the plant nuclei. We identified a phenolic compound, chloroxynil, which increased the genetic transformation of L. japonicus by Agrobacterium tumefaciens strain EHA105. Characterization of the mode of chloroxynil action indicated that it enhanced Agrobacterium-mediated transformation through the activation of the Agrobacterium vir gene expression, similar to acetosyringone, a phenolic compound known to improve Agrobacterium-mediated transformation efficiency. Transient transformation efficiency of L. japonicus with 5 μM chloroxynil was 60- and 6- fold higher than that of the control and acetosyringone treatment, respectively. In addition, transgenic L. japonicus lines were successfully generated by 5 μM chloroxynil treatment.Furthermore, we show that chloroxynil improves L. japonicus transformation by Agrobacterium strain GV3101 and rice transformation. Our results demonstrate that chloroxynil significantly improves Agrobacterium tumefaciens-mediated transformation efficiency of various agriculturally important crops.

  6. Interplay between Natural Killer Cells and Anti-HER2 Antibodies: Perspectives for Breast Cancer Immunotherapy

    Directory of Open Access Journals (Sweden)

    Aura Muntasell

    2017-11-01

    Full Text Available Overexpression of the human epidermal growth factor receptor 2 (HER2 defines a subgroup of breast tumors with aggressive behavior. The addition of HER2-targeted antibodies (i.e., trastuzumab, pertuzumab to chemotherapy significantly improves relapse-free and overall survival in patients with early-stage and advanced disease. Nonetheless, considerable proportions of patients develop resistance to treatment, highlighting the need for additional and co-adjuvant therapeutic strategies. HER2-specific antibodies can trigger natural killer (NK cell-mediated antibody-dependent cellular cytotoxicity and indirectly enhance the development of tumor-specific T cell immunity; both mechanisms contributing to their antitumor efficacy in preclinical models. Antibody-dependent NK cell activation results in the release of cytotoxic granules as well as the secretion of pro-inflammatory cytokines (i.e., IFNγ and TNFα and chemokines. Hence, NK cell tumor suppressive functions include direct cytolytic killing of tumor cells as well as the regulation of subsequent antitumor adaptive immunity. Albeit tumors with gene expression signatures associated to the presence of cytotoxic lymphocyte infiltrates benefit from trastuzumab-based treatment, NK cell-related biomarkers of response/resistance to HER2-specific therapeutic antibodies in breast cancer patients remain elusive. Several variables, including (i the configuration of the patient NK cell repertoire; (ii tumor molecular features (i.e., estrogen receptor expression; (iii concomitant therapeutic regimens (i.e., chemotherapeutic agents, tyrosine kinase inhibitors; and (iv evasion mechanisms developed by progressive breast tumors, have been shown to quantitatively and qualitatively influence antibody-triggered NK cell responses. In this review, we discuss possible interventions for restoring/enhancing the therapeutic activity of HER2 therapeutic antibodies by harnessing NK cell antitumor potential through

  7. Preexisting Antibodies to an F(ab′)2 Antibody Therapeutic and Novel Method for Immunogenicity Assessment

    OpenAIRE

    Ruppel, Jane; Brady, Ann; Elliott, Rebecca; Leddy, Cecilia; Palencia, Marco; Coleman, Daniel; Couch, Jessica A.; Wakshull, Eric

    2016-01-01

    Anti-therapeutic antibodies (ATAs) may impact drug exposure and activity and induce immune complex mediated toxicity; therefore the accurate measurement of ATA is important for the analysis of drug safety and efficacy. Preexisting ATAs to the hinge region of anti-Delta like ligand 4 (anti-DLL4) F(ab′)2, a potential antitumor therapeutic, were detected in cynomolgus monkey serum, which presented a challenge in developing assays for detecting treatment induced ATA. A total ATA assay was develop...

  8. Enzymatic Inactivation of Endogenous IgG by IdeS Enhances Therapeutic Antibody Efficacy.

    Science.gov (United States)

    Järnum, Sofia; Runström, Anna; Bockermann, Robert; Winstedt, Lena; Crispin, Max; Kjellman, Christian

    2017-09-01

    Endogenous plasma IgG sets an immunologic threshold that dictates the activity of tumor-directed therapeutic antibodies. Saturation of cellular antibody receptors by endogenous antibody limits antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). Here, we show how enzymatic cleavage of IgG using the bacterial enzyme IdeS can be utilized to empty both high and low affinity Fcγ-receptors and clear the entire endogenous antibody pool. Using in vitro models, tumor animal models as well as ex vivo analysis of sera collected during a previous clinical trial with IdeS, we show how clearing of competing plasma antibody levels with IdeS unblocks cellular antibody receptors. We show that therapeutic antibodies against breast cancer (trastuzumab), colon cancer (cetuximab), and lymphomas (rituximab and alemtuzumab) can be potentiated when endogenous IgG is removed. Overall, IdeS is shown to be a potent tool to reboot the human antibody repertoire and to generate a window to preferentially load therapeutic antibodies onto effector cells and thereby create an armada of dedicated tumor-seeking immune cells. Mol Cancer Ther; 16(9); 1887-97. ©2017 AACR . ©2017 American Association for Cancer Research.

  9. Monitoring the systemic human memory B cell compartment of melanoma patients for anti-tumor IgG antibodies.

    Directory of Open Access Journals (Sweden)

    Amy E Gilbert

    Full Text Available Melanoma, a potentially lethal skin cancer, is widely thought to be immunogenic in nature. While there has been much focus on T cell-mediated immune responses, limited knowledge exists on the role of mature B cells. We describe an approach, including a cell-based ELISA, to evaluate mature IgG antibody responses to melanoma from human peripheral blood B cells. We observed a significant increase in antibody responses from melanoma patients (n = 10 to primary and metastatic melanoma cells compared to healthy volunteers (n = 10 (P<0.0001. Interestingly, we detected a significant reduction in antibody responses to melanoma with advancing disease stage in our patient cohort (n = 21 (P<0.0001. Overall, 28% of melanoma patient-derived B cell cultures (n = 1,800 compared to 2% of cultures from healthy controls (n = 600 produced antibodies that recognized melanoma cells. Lastly, a patient-derived melanoma-specific monoclonal antibody was selected for further study. This antibody effectively killed melanoma cells in vitro via antibody-mediated cellular cytotoxicity. These data demonstrate the presence of a mature systemic B cell response in melanoma patients, which is reduced with disease progression, adding to previous reports of tumor-reactive antibodies in patient sera, and suggesting the merit of future work to elucidate the clinical relevance of activating humoral immune responses to cancer.

  10. Monitoring the Systemic Human Memory B Cell Compartment of Melanoma Patients for Anti-Tumor IgG Antibodies

    Science.gov (United States)

    Gilbert, Amy E.; Karagiannis, Panagiotis; Dodev, Tihomir; Koers, Alexander; Lacy, Katie; Josephs, Debra H.; Takhar, Pooja; Geh, Jenny L. C.; Healy, Ciaran; Harries, Mark; Acland, Katharine M.; Rudman, Sarah M.; Beavil, Rebecca L.; Blower, Philip J.; Beavil, Andrew J.; Gould, Hannah J.; Spicer, James; Nestle, Frank O.; Karagiannis, Sophia N.

    2011-01-01

    Melanoma, a potentially lethal skin cancer, is widely thought to be immunogenic in nature. While there has been much focus on T cell-mediated immune responses, limited knowledge exists on the role of mature B cells. We describe an approach, including a cell-based ELISA, to evaluate mature IgG antibody responses to melanoma from human peripheral blood B cells. We observed a significant increase in antibody responses from melanoma patients (n = 10) to primary and metastatic melanoma cells compared to healthy volunteers (n = 10) (P<0.0001). Interestingly, we detected a significant reduction in antibody responses to melanoma with advancing disease stage in our patient cohort (n = 21) (P<0.0001). Overall, 28% of melanoma patient-derived B cell cultures (n = 1,800) compared to 2% of cultures from healthy controls (n = 600) produced antibodies that recognized melanoma cells. Lastly, a patient-derived melanoma-specific monoclonal antibody was selected for further study. This antibody effectively killed melanoma cells in vitro via antibody-mediated cellular cytotoxicity. These data demonstrate the presence of a mature systemic B cell response in melanoma patients, which is reduced with disease progression, adding to previous reports of tumor-reactive antibodies in patient sera, and suggesting the merit of future work to elucidate the clinical relevance of activating humoral immune responses to cancer. PMID:21559411

  11. Search for new and improved radiolabeling methods for monoclonal antibodies

    International Nuclear Information System (INIS)

    Hiltunen, J.V.

    1993-01-01

    In this review the selection of different radioisotopes is discussed as well as the various traditional or newer methods to introduce the radiolabel into the antibody structure. Labeling methods for radiohalogens, for technetium and rhenium isotopes, and for 3-valent cation radiometals are reviewed. Some of the newer methods offer simplified labeling procedures, but usually the new methods are more complicated than the earlier ones. However, new labeling methods are available for almost any radioelement group and they may result in better preserved original natural of the antibody and lead to better clinical results. (orig./MG)

  12. Ah receptor mediated suppression of the antibody response in mice is primarily dependent on the Ah phenotype of lymphoid tissue

    International Nuclear Information System (INIS)

    Silkworth, J.B.; Antrim, L.A.; Sack, G.

    1986-01-01

    Halogenated aromatic hydrocarbons act through the aromatic hydrocarbon (Ah) receptor in mice to produce a series of toxic effects of the immune system. The receptor protein is a product of the Ah gene locus. Ah responsive (Ahb/Ahb) mice express a high affinity receptor in both lymphoid and nonlymphoid tissues whereas nonresponsive Ahd/Ahd mice express a poor affinity receptor. To determine the role of the Ah receptor of lymphoid tissue relative to that of nonlymphoid tissue in the induction of immune impairment, bone marrow was used to reconstitute lethally irradiated mice of the same or opposite Ah phenotype. All mice were given 3,3',4,4'-tetrachlorobiphenyl (35 and 350 mumol/kg) ip 2 days before immunization with sheep erythrocytes (SRBC). The immune response to this T dependent antigen and organ weights were determined 5 or 7 days later in normal or chimeric mice, respectively. Monoclonal Lyt 1.1 and Lyt 1.2 antibodies were used to establish the origin of the cells which repopulated the chimeric thymuses. The immune responses of both BALB/cBy (Ahb/Ahb) and the BALB/cBy X DBA/2 hybrid, CByD2F1 (Ahb/Ahd), were significantly suppressed but DBA/2 mice were unaffected. The immune responses of chimeric BALB/cBy----BALB/cBy and BALB/cBy----DBA/2 (donor----recipient) mice were also significantly suppressed and thymic atrophy was observed in both cases. The serum anti-SRBC antibody titers of DBA/2----BALB/cBy chimeras were also significantly decreased although not to the same extent as in BALB/cBy----DBA/2 mice. Chimeric DBA/2----DBA/2 mice were not affected. These results indicate that the sensitivity to Ah receptor mediated suppression of the antibody response is primarily determined by the Ah phenotype of the lymphoid tissue

  13. A Single Domain–Based Anti-Her2 Antibody Has Potent Antitumor Activities

    Directory of Open Access Journals (Sweden)

    Xiaoqiong Wu

    2018-04-01

    Full Text Available Human epidermal growth factor receptor 2 (HER2 is overexpressed in approximately 20% to 30% of breast cancers and various other types of cancers, which plays a vital role in the cancer progression. Monoclonal antibodies targeting Her2 are now used in the clinic to treat Her2 overexpression cancer patients. However, relapse or resistance is frequent with the current therapies. To generate a new treatment avenue against Her2, we immunized and selected a specific anti-Her2 single domain antibody C3 for further studies. The C3-Fc antibody drove antibody-dependent cell-mediated cytotoxicity against Her2-positive tumor cells in vitro and resulted in potent antitumor growth in vivo. These data suggest that the C3-Fc antibody may provide an alternative avenue for Her2-positive cancer therapy.

  14. N-methyl-D-aspartate receptor antibody-mediated neurological disease: results of a UK-based surveillance study in children.

    Science.gov (United States)

    Wright, Sukhvir; Hacohen, Yael; Jacobson, Leslie; Agrawal, Shakti; Gupta, Rajat; Philip, Sunny; Smith, Martin; Lim, Ming; Wassmer, Evangeline; Vincent, Angela

    2015-06-01

    N-methyl-D-aspartate receptor antibody (NMDAR-Ab) encephalitis is a well-recognised clinico-immunological syndrome that presents with neuropsychiatric symptoms cognitive decline, movement disorder and seizures. This study reports the clinical features, management and neurological outcomes of paediatric NMDAR-Ab-mediated neurological disease in the UK. A prospective surveillance study. Children with NMDAR-Ab-mediated neurological diseases were voluntarily reported to the British Neurological Surveillance Unit (BPNSU) from November 2010 to December 2011. Initial and follow-up questionnaires were sent out to physicians. Thirty-one children fulfilled the criteria for the study. Eight presented during the study period giving an incidence of 0.85 per million children per year (95% CI 0.64 to 1.06); 23 cases were historical. Behavioural change and neuropsychiatric features were present in 90% of patients, and seizures and movement disorders both in 67%. Typical NMDAR-Ab encephalitis was reported in 24 children and partial phenotype without encephalopathy in seven, including predominantly psychiatric (four) and movement disorder (three). All patients received steroids, 22 (71%) received intravenous immunoglobulin, 9 (29%) received plasma exchange,and 10 (32%) received second-line immunotherapy. Of the 23 patients who were diagnosed early, 18 (78%) made a full recovery compared with only 1 of 8 (13%) of the late diagnosed patients (p=0.002, Fisher's exact test). Seven patients relapsed, with four needing additional second-line immunotherapy. Paediatric NMDAR-Ab-mediated neurological disease appears to be similar to adult NMDAR-Ab encephalitis, but some presented with a partial phenotype. Early treatment was associated with a quick and often full recovery. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  15. Dual Constant Domain-Fab: A novel strategy to improve half-life and potency of a Met therapeutic antibody.

    Science.gov (United States)

    Cignetto, Simona; Modica, Chiara; Chiriaco, Cristina; Fontani, Lara; Milla, Paola; Michieli, Paolo; Comoglio, Paolo M; Vigna, Elisa

    2016-06-01

    The kinase receptor encoded by the Met oncogene is a sensible target for cancer therapy. The chimeric monovalent Fab fragment of the DN30 monoclonal antibody (MvDN30) has an odd mechanism of action, based on cell surface removal of Met via activation of specific plasma membrane proteases. However, the short half-life of the Fab, due to its low molecular weight, is a severe limitation for the deployment in therapy. This issue was addressed by increasing the Fab molecular weight above the glomerular filtration threshold through the duplication of the constant domains, in tandem (DCD-1) or reciprocally swapped (DCD-2). The two newly engineered molecules showed biochemical properties comparable to the original MvDN30 in vitro, acting as full Met antagonists, impairing Met phosphorylation and activation of downstream signaling pathways. As a consequence, Met-mediated biological responses were inhibited, including anchorage-dependent and -independent cell growth. In vivo DCD-1 and DCD-2 showed a pharmacokinetic profile significantly improved over the original MvDN30, doubling the circulating half-life and reducing the clearance. In pre-clinical models of cancer, generated by injection of tumor cells or implant of patient-derived samples, systemic administration of the engineered molecules inhibited the growth of Met-addicted tumors. Copyright © 2016 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  16. CD47 limits antibody dependent phagocytosis against non-malignant B cells.

    Science.gov (United States)

    Gallagher, Sandra; Turman, Sean; Lekstrom, Kristen; Wilson, Susan; Herbst, Ronald; Wang, Yue

    2017-05-01

    Recent studies have demonstrated the importance of CD47 in protecting malignant B cells from antibody dependent cellular phagocytosis (ADCP). Combined treatment of anti-CD47 and -CD20 antibodies synergistically augment elimination of tumor B cells in xenograft mouse models. This has led to the development of novel reagents that can potentially enhance killing of malignant B cells in patients. B cell depleting therapy is also a promising treatment for autoimmune patients. In the current study, we aimed to investigate whether or not CD47 protects non-malignant B cells from ADCP. We show that CD47 is expressed on all B cells in mice, with the highest level on plasma cells in bone marrow and spleen. Although its expression is dispensable for B cell development in mice, CD47 on B cells limits antibody mediated phagocytosis. B cell depletion following in vivo anti-CD19 treatment is more efficient in CD47-/- mice than in wild type mice. In vitro, both naïve and activated B cells from CD47-/- mice are more sensitive to ADCP than wild type B cells. Lastly, we show in an ADCP assay that blocking CD47 can enhance anti-CD19 antibody mediated phagocytosis of wild type B cells. These results suggest that in addition to its already demonstrated benefit in cancer, targeting CD47 may be used as an adjunct in combination with B cell depletion antibodies for treatment of autoimmune diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Analyses of the peripheral immunome following multiple administrations of avelumab, a human IgG1 anti-PD-L1 monoclonal antibody

    OpenAIRE

    Donahue, Renee N.; Lepone, Lauren M.; Grenga, Italia; Jochems, Caroline; Fantini, Massimo; Madan, Ravi A.; Heery, Christopher R.; Gulley, James L.; Schlom, Jeffrey

    2017-01-01

    Background Multiple anti-PD-L1/PD-1 checkpoint monoclonal antibodies (MAb) have shown clear evidence of clinical benefit. All except one have been designed or engineered to omit the possibility to mediate antibody-dependent cell-mediated cytotoxicity (ADCC) as a second potential mode of anti-tumor activity; the reason for this is the concern of lysis of PD-L1 positive immune cells. Avelumab is a fully human IgG1 MAb which has been shown in prior in vitro studies to mediate ADCC versus a range...

  18. Antibody responses in allogeneic radiation chimeras

    International Nuclear Information System (INIS)

    Coico, R.F.

    1982-01-01

    The construction of long-lived allogeneic radiation chimeras, free of graft-versus-host disease, has been achieved using serologic elimination of Thy 1 + cells from donor bone marrow. Humoral immune function was not restored in these animals as evidenced by lack of primary antibody responses to a T cell-dependent antigen, namely, sheep erythrocytes (SRBC) both in vivo and in vitro. No evidence for a suppressor cell-mediated mechanism was found. Using separated chimera spleen cell populations and specific helper cell soluble mediators, the functional capabilities of chimera B cells, T cells, and macrophages were assessed. These findings suggested that the failure of chimeras to produce antibody is not the result of impaired B cell, T cell, or macrophage function, but rather, that it is due to ineffective cellular interactions. Physiologic cellular interactions depend upon the sharing of major histocompatibility complex (MHC) determinants between interacting cells. However, the self-recognition repertoire of developing T cells may be influenced by the environment which these cells differentiate such that they learn to recognize host MHC determinants as self. These findings support the interpretation that the immunologic hyporeactivity of allogeneic bone marrow chimeras reflects the role of the host environment in restricting the interactive capabilities of donor-derived cells

  19. Progranulin antibodies in autoimmune diseases.

    Science.gov (United States)

    Thurner, Lorenz; Preuss, Klaus-Dieter; Fadle, Natalie; Regitz, Evi; Klemm, Philipp; Zaks, Marina; Kemele, Maria; Hasenfus, Andrea; Csernok, Elena; Gross, Wolfgang L; Pasquali, Jean-Louis; Martin, Thierry; Bohle, Rainer Maria; Pfreundschuh, Michael

    2013-05-01

    Systemic vasculitides constitute a heterogeneous group of diseases. Autoimmunity mediated by B lymphocytes and their humoral effector mechanisms play a major role in ANCA-associated vasculitis (AAV) as well as in non-ANCA associated primary systemic vasculitides and in the different types of autoimmune connective tissue disorders and rheumatoid arthritis. In order to detect autoantibodies in systemic vasculitides, we screened protein macroarrays of human cDNA expression libraries with sera from patients with ANCA-associated and ANCA-negative primary systemic vasculitides. This approach led to the identification of antibodies against progranulin, a 88 kDA secreted glycoprotein with strong anti-inflammatory activity in the course of disease of giant-cell arteritis/polymyalgia rheumatica (14/65), Takayasu's arteritis (4/13), classical panarteritis nodosa (4/10), Behcet's disease (2/6) and in the course of disease in granulomatosis with polyangiitis (31/75), Churg-Strauss syndrome (7/23) and in microscopic polyangiitis (7/19). In extended screenings the progranulin antibodies were also detected in other autoimmune diseases such as systemic lupus erythematosus (39/91) and rheumatoid arthritis (16/44). Progranulin antibodies were detected only in 1 of 97 healthy controls. Anti-progranulin positive patients with systemic vasculitides, systemic lupus erythematosus or rheumatoid arthritis had significant lower progranulin plasma levels, indicating a neutralizing effect. In light of the anti-inflammatory effects of progranulin, progranulin antibodies might exert pro-inflammatory effects thus contributing to the pathogenesis of the respective autoimmune diseases and might serve as a marker for disease activity. This hypothesis is supported by the fact that a positive progranulin antibody status was associated with active disease in granulomatosis with polyangiitis. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Improving food and agricultural production. Thailand. Application on monoclonal antibodies for progesterone measurement

    International Nuclear Information System (INIS)

    Butcher, G.W.

    1991-01-01

    The duties of the mission were to provide instructions on the maintenance of hybridoma cell lines and their culture and the harvesting of monoclonal antibodies; to assist the counterparts in Thailand to develop work plans for the use of monoclonal antibodies in radioimmunoassay measurements of progesterone; and to assess the need for and feasibility of establishing a laboratory for producing monoclonal antibodies directed against progesterone. The report contains a summary of the activities performed in fulfillment of these duties

  1. Daratumumab: a first-in-class CD38 monoclonal antibody for the treatment of multiple myeloma

    Directory of Open Access Journals (Sweden)

    Larysa Sanchez

    2016-06-01

    Full Text Available Abstract Daratumumab is a human monoclonal antibody that targets CD38, a cell surface protein that is overexpressed on multiple myeloma (MM cells. Preclinical studies have shown that daratumumab induces MM cell death through several mechanisms, including complement-dependent cytotoxicity (CDC, antibody-dependent cell-mediated cytotoxicity (ADCC, antibody-dependent cellular phagocytosis (ADCP, and apoptosis. Given the encouraging efficacy and acceptable safety profile of daratumumab demonstrated in clinical trials, daratumumab has emerged as a novel treatment option for myeloma and became the first monoclonal antibody approved by the FDA for the treatment of MM.

  2. Bispecific Antibodies as a Development Platform for New Concepts and Treatment Strategies

    Directory of Open Access Journals (Sweden)

    Fa Yang

    2016-12-01

    Full Text Available With the development of molecular cloning technology and the deep understanding of antibody engineering, there are diverse bispecific antibody formats from which to choose to pursue the optimal biological activity and clinical purpose. The single-chain-based bispecific antibodies usually bridge tumor cells with immune cells and form an immunological synapse because of their relatively small size. Bispecific antibodies in the IgG format include asymmetric bispecific antibodies and homodimerized bispecific antibodies, all of which have an extended blood half-life and their own crystalline fragment (Fc-mediated functions. Besides retargeting effector cells to the site of cancer, new applications were established for bispecific antibodies. Bispecific antibodies that can simultaneously bind to cell surface antigens and payloads are a very ideal delivery system for therapeutic use. Bispecific antibodies that can inhibit two correlated signaling molecules at the same time can be developed to overcome inherent or acquired resistance and to be more efficient angiogenesis inhibitors. Bispecific antibodies can also be used to treat hemophilia A by mimicking the function of factor VIII. Bispecific antibodies also have broad application prospects in bone disorders and infections and diseases of the central nervous system. The latest developments of the formats and application of bispecific antibodies will be reviewed. Furthermore, the challenges and perspectives are summarized in this review.

  3. Pre-transplant soluble CD30 in combination with total DSA but not pre-transplant C1q-DSA predicts antibody-mediated graft loss in presensitized high-risk kidney transplant recipients.

    Science.gov (United States)

    Schaefer, S M; Süsal, C; Opelz, G; Döhler, B; Becker, L E; Klein, K; Sickmüller, S; Waldherr, R; Macher-Goeppinger, S; Schemmer, P; Beimler, J; Zeier, M; Morath, C

    2016-02-01

    Presensitized kidney transplant recipients are at high-risk for early antibody-mediated rejection. We studied the impact of pre- and post-transplant donor-specific human leukocyte antigen (HLA) antibodies (DSA) and T-cell-activation on the occurrence of antibody-mediated rejection episodes (AMR) and graft loss (AMR-GL) in a unique cohort of 80 desensitized high-risk kidney transplant recipients. Patients with pre-transplant DSA demonstrated more AMR episodes than patients without DSA, but did not show a significantly increased rate of AMR-GL. The rates of AMR and AMR-GL were not significantly increased in patients with complement split product (C1q)-binding pre-transplant DSA. Pre-transplant C1q-DSA became undetectable post-transplant in 11 of 13 (85%) patients; 2 (18%) of these 11 patients showed AMR but no AMR-GL. In contrast, the post-transplant presence of C1q-DSA was associated with significantly higher rates of AMR (86 vs 33 vs 0%; P transplant DSA without C1q-binding or the absence of DSA. Patients with both pre-transplant DSA and evidence of pre-transplant T-cell-activation as indicated by soluble CD30-positivity showed a significantly increased risk for AMR-GL [HR = 11.1, 95% confidence interval (CI) = 1.68-73.4; log-rank P = 0.013]. In these high-risk patients, AMR-GL was associated with total DSA in combination with T-cell-activation pre-transplant, and de novo or persistent C1q-binding DSA post-transplant. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. An improved yeast transformation method for the generation of very large human antibody libraries.

    Science.gov (United States)

    Benatuil, Lorenzo; Perez, Jennifer M; Belk, Jonathan; Hsieh, Chung-Ming

    2010-04-01

    Antibody library selection by yeast display technology is an efficient and highly sensitive method to identify binders to target antigens. This powerful selection tool, however, is often hampered by the typically modest size of yeast libraries (approximately 10(7)) due to the limited yeast transformation efficiency, and the full potential of the yeast display technology for antibody discovery and engineering can only be realized if it can be coupled with a mean to generate very large yeast libraries. We describe here a yeast transformation method by electroporation that allows for the efficient generation of large antibody libraries up to 10(10) in size. Multiple components and conditions including CaCl(2), MgCl(2), sucrose, sorbitol, lithium acetate, dithiothreitol, electroporation voltage, DNA input and cell volume have been tested to identify the best combination. By applying this developed protocol, we have constructed a 1.4 x 10(10) human spleen antibody library essentially in 1 day with a transformation efficiency of 1-1.5 x 10(8) transformants/microg vector DNA. Taken together, we have developed a highly efficient yeast transformation method that enables the generation of very large and productive human antibody libraries for antibody discovery, and we are now routinely making 10(9) libraries in a day for antibody engineering purposes.

  5. Cell-free synthesis of functional antibody fragments to provide a structural basis for antibody-antigen interaction.

    Directory of Open Access Journals (Sweden)

    Takayoshi Matsuda

    Full Text Available Growing numbers of therapeutic antibodies offer excellent treatment strategies for many diseases. Elucidation of the interaction between a potential therapeutic antibody and its target protein by structural analysis reveals the mechanism of action and offers useful information for developing rational antibody designs for improved affinity. Here, we developed a rapid, high-yield cell-free system using dialysis mode to synthesize antibody fragments for the structural analysis of antibody-antigen complexes. Optimal synthesis conditions of fragments (Fv and Fab of the anti-EGFR antibody 059-152 were rapidly determined in a day by using a 30-μl-scale unit. The concentration of supplemented disulfide isomerase, DsbC, was critical to obtaining soluble antibody fragments. The optimal conditions were directly applicable to a 9-ml-scale reaction, with linear scalable yields of more than 1 mg/ml. Analyses of purified 059-152-Fv and Fab showed that the cell-free synthesized antibody fragments were disulfide-bridged, with antigen binding activity comparable to that of clinical antibodies. Examination of the crystal structure of cell-free synthesized 059-152-Fv in complex with the extracellular domain of human EGFR revealed that the epitope of 059-152-Fv broadly covers the EGF binding surface on domain III, including residues that formed critical hydrogen bonds with EGF (Asp355EGFR, Gln384EGFR, H409EGFR, and Lys465EGFR, so that the antibody inhibited EGFR activation. We further demonstrated the application of the cell-free system to site-specific integration of non-natural amino acids for antibody engineering, which would expand the availability of therapeutic antibodies based on structural information and rational design. This cell-free system could be an ideal antibody-fragment production platform for functional and structural analysis of potential therapeutic antibodies and for engineered antibody development.

  6. The state-of-play and future of antibody therapeutics.

    Science.gov (United States)

    Elgundi, Zehra; Reslan, Mouhamad; Cruz, Esteban; Sifniotis, Vicki; Kayser, Veysel

    2017-12-01

    It has been over four decades since the development of monoclonal antibodies (mAbs) using a hybridoma cell line was first reported. Since then more than thirty therapeutic antibodies have been marketed, mostly as oncology, autoimmune and inflammatory therapeutics. While antibodies are very efficient, their cost-effectiveness has always been discussed owing to their high costs, accumulating to more than one billion dollars from preclinical development through to market approval. Because of this, therapeutic antibodies are inaccessible to some patients in both developed and developing countries. The growing interest in biosimilar antibodies as affordable versions of therapeutic antibodies may provide alternative treatment options as well potentially decreasing costs. As certain markets begin to capitalize on this opportunity, regulatory authorities continue to refine the requirements for demonstrating quality, efficacy and safety of biosimilar compared to originator products. In addition to biosimilars, innovations in antibody engineering are providing the opportunity to design biobetter antibodies with improved properties to maximize efficacy. Enhancing effector function, antibody drug conjugates (ADC) or targeting multiple disease pathways via multi-specific antibodies are being explored. The manufacturing process of antibodies is also moving forward with advancements relating to host cell production and purification processes. Studies into the physical and chemical degradation pathways of antibodies are contributing to the design of more stable proteins guided by computational tools. Moreover, the delivery and pharmacokinetics of antibody-based therapeutics are improving as optimized formulations are pursued through the implementation of recent innovations in the field. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Role of the Antigen Capture Pathway in the Induction of a Neutralizing Antibody Response to Anthrax Protective Antigen

    Directory of Open Access Journals (Sweden)

    Anita Verma

    2018-02-01

    Full Text Available Toxin neutralizing antibodies represent the major mode of protective immunity against a number of toxin-mediated bacterial diseases, including anthrax; however, the cellular mechanisms that lead to optimal neutralizing antibody responses remain ill defined. Here we show that the cellular binding pathway of anthrax protective antigen (PA, the binding component of anthrax toxin, determines the toxin neutralizing antibody response to this antigen. PA, which binds cellular receptors and efficiently enters antigen-presenting cells by receptor-mediated endocytosis, was found to elicit robust anti-PA IgG and toxin neutralizing antibody responses. In contrast, a receptor binding-deficient mutant of PA, which does not bind receptors and only inefficiently enters antigen-presenting cells by macropinocytosis, elicited very poor antibody responses. A chimeric protein consisting of the receptor binding-deficient PA mutant tethered to the binding subunit of cholera toxin, which efficiently enters cells using the cholera toxin receptor rather than the PA receptor, elicited an anti-PA IgG antibody response similar to that elicited by wild-type PA; however, the chimeric protein elicited a poor toxin neutralizing antibody response. Taken together, our results demonstrate that the antigen capture pathway can dictate the magnitudes of the total IgG and toxin neutralizing antibody responses to PA as well as the ratio of the two responses.

  8. Disassembly and reassembly of human papillomavirus virus-like particles produces more virion-like antibody reactivity

    Directory of Open Access Journals (Sweden)

    Zhao Qinjian

    2012-02-01

    Full Text Available Abstract Background Human papillomavirus (HPV vaccines based on major capsid protein L1 are licensed in over 100 countries to prevent HPV infections. The yeast-derived recombinant quadrivalent HPV L1 vaccine, GARDASIL(R, has played an important role in reducing cancer and genital warts since its introduction in 2006. The L1 proteins self-assemble into virus-like particles (VLPs. Results VLPs were subjected to post-purification disassembly and reassembly (D/R treatment during bioprocessing to improve VLP immunoreactivity and stability. The post-D/R HPV16 VLPs and their complex with H16.V5 neutralizing antibody Fab fragments were visualized by cryo electron microscopy, showing VLPs densely decorated with antibody. Along with structural improvements, post-D/R VLPs showed markedly higher antigenicity to conformational and neutralizing monoclonal antibodies (mAbs H16.V5, H16.E70 and H263.A2, whereas binding to mAbs recognizing linear epitopes (H16.J4, H16.O7, and H16.H5 was greatly reduced. Strikingly, post-D/R VLPs showed no detectable binding to H16.H5, indicating that the H16.H5 epitope is not accessible in fully assembled VLPs. An atomic homology model of the entire HPV16 VLP was generated based on previously determined high-resolution structures of bovine papillomavirus and HPV16 L1 pentameric capsomeres. Conclusions D/R treatment of HPV16 L1 VLPs produces more homogeneous VLPs with more virion-like antibody reactivity. These effects can be attributed to a combination of more complete and regular assembly of the VLPs, better folding of L1, reduced non-specific disulfide-mediated aggregation and increased stability of the VLPs. Markedly different antigenicity of HPV16 VLPs was observed upon D/R treatment with a panel of monoclonal antibodies targeting neutralization sensitive epitopes. Multiple epitope-specific assays with a panel of mAbs with different properties and epitopes are required to gain a better understanding of the immunochemical

  9. Antithyroglobulin antibody

    Science.gov (United States)

    Thyroglobulin antibody; Thyroiditis - thyroglobulin antibody; Hypothyroidism - thyroglobulin antibody; Thyroiditis - thyroglobulin antibody; Graves disease - thyroglobulin antibody; Underactive thyroid - thyroglobulin antibody

  10. Avelumab: combining immune checkpoint inhibition and antibody-dependent cytotoxicity.

    Science.gov (United States)

    Hamilton, Gerhard; Rath, Barbara

    2017-04-01

    Immune checkpoint inhibition holds great promise for selected tumors. The human monoclonal antibody (mAB) avelumab is directed to programmed death ligand-1 (PD-L1) and is supposed to inhibit the immunosuppressive PD-L1/PD-1 interaction and, furthermore, effect antibody-dependent cytotoxicity (ADCC) lysis of tumor cells. Areas covered: This article presents an overview of the current means to activate the antitumor immune defense by targeting PD-1 or PD-L1 with mABs and their possible role in ADCC-mediated tumor cell elimination. Expert opinion: Avelumab contains a Fc region which can bind cognate receptors on immune effector cells and induce ADCC-mediated tumor cell lysis, in contrast to other mABs directed to PD-1/PD-L1 which lack the ability to trigger ADCC due to belonging to the IgG4 subclass or possessing a mutated Fc region. Preclinical and clinical data indicate that avelumab can be safely administered to cancer patients with a toxicity profile comparable to other mABs and without lysis of PD-L1-positive activated immune cells. This antibody yielded durable responses in a phase II trial in advanced Merkel cell carcinoma patients. Tumor cell lysis by avelumab prevents cells from resorting to alternative checkpoints as shown by targeting PD-1 and the upregulation of TIM-3.

  11. Immune-mediated rippling muscle disease and myasthenia gravis.

    Science.gov (United States)

    Bettini, Mariela; Gonorazky, Hernan; Chaves, Marcelo; Fulgenzi, Ernesto; Figueredo, Alejandra; Christiansen, Silvia; Cristiano, Edgardo; Bertini, Enrico S; Rugiero, Marcelo

    2016-10-15

    Cases of acquired rippling muscle disease in association with myasthenia gravis have been reported. We present three patients with iRMD (immune-mediated rippling muscle disease) and AChR-antibody positive myasthenia gravis. None of them had thymus pathology. They presented exercise-induced muscle rippling combined with generalized myasthenia gravis. One of them had muscle biopsy showing a myopathic pattern and a patchy immunostaining with caveolin antibodies. They were successfully treated steroids and azathioprine. The immune nature of this association is supported by the response to immunotherapies and the positivity of AChR-antibodies. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Different mechanisms are involved in the antibody mediated inhibition of ligand binding to the urokinase receptor

    DEFF Research Database (Denmark)

    List, K; Høyer-Hansen, G; Rønne, E

    1999-01-01

    Certain monoclonal antibodies are capable of inhibiting the biological binding reactions of their target proteins. At the molecular level, this type of effect may be brought about by completely different mechanisms, such as competition for common binding determinants, steric hindrance or interfer......Certain monoclonal antibodies are capable of inhibiting the biological binding reactions of their target proteins. At the molecular level, this type of effect may be brought about by completely different mechanisms, such as competition for common binding determinants, steric hindrance......) can be employed as a highly useful tool to characterize the inhibitory mechanism of specific antagonist antibodies. Two inhibitory antibodies against uPAR, mAb R3 and mAb R5, were shown to exhibit competitive and non-competitive inhibition, respectively, of ligand binding to the receptor. The former...

  13. Unexplained infertility: identification of anti sperm antibodies using radiometric immunoassay

    International Nuclear Information System (INIS)

    Megahed, Y.M.; Elnabarawy, F.; Hamada, T.; Ayiad, S.K.

    1992-01-01

    Several methods have been employed to measure anti sperm antibodies with variable sensitivity and specificity in serum and secretion of infertile patients. All of them are not precise means for identification of the presence of anti sperm antibodies for patients with unexplained infertility (Haas et al, 1980). Therefore, the modified radiolabelled anti globulin test, that has been used successfully to identify and quantitate the antibodies directed towards other human cell surfaces, was applied. A total number of 128 subjects in different groups were studied to quantitate the circulating anti sperm antibodies using the modified procedure. The present data revealed that the highest and the most significant incidence were found in the patients secretions (semen and cervical mucus) with unexplained infertility, as well as in the group of males with varicocele. Therefore it is greatly advisable to use the modified radiolabelled technique as a quantitative assay, which will be helpful in management of infertility in patients with unexplained and mediated infertility.3 tab., 4 fig

  14. Studies of cytotoxic antibodies against eye muscle antigens in patients with thyroid-associated ophthalmopathy

    International Nuclear Information System (INIS)

    Zhang, Z.-G.; Hiromatsu, Y.; Salvi, M.; Triller, H.; Bernard, N.; Wall, J.R.; Medeiros-Neto, G.; Iacona, A.; Lima, N.

    1989-01-01

    We have studied the prevalence and significance of cytotoxic antibodies against human eye muscle cells, as detected in antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-mediated antibody-dependent cytotoxicity (CMAC) in 51 Cr release assays, in patients with Graves' ophthalmopathy or Hashimoto's thyroiditis. A high prevalence of positive ADCC tests was found in all groups of patients with ophthalmopathy tested. Tests were positive in 64% of patients with Graves' ophthalmopathy from an area of severe iodine deficiency (Sao Paulo) and in 64% of such patients from an iodine replete area (Montreal). In patients with so-called ''euthyroid ophthalmopathy'', i.e. eye disease associated with thyroiditis, ADCC tests were positive in 75 and 38% of patients from the two areas, respectively, while tests were positive in 40 and 22%, respectively, of patients with Graves' hyperthyroidism without evident eye disease. In normal subjects, levels of 51 Cr release was always at background levels. In a group of patients from the high-iodine area, levels of antibodies in ADCC correlated positively with the intraocular pressure (mmHg) in primary position as a parameter of eye muscle dysfunction. In patients with ophthalmopathy, positive ADCC tests were assciated with antibodies to eye muscle membrane antigens of 55,65 and 95 kD as detected by immunoblotting, although the correlation was not close for any antigen. in contrast, CMAC tests were negative in all patients with ophthalmopathy. We also tested 9 mouse and 10 human monoclonal antibodies, reactive with orbital antigens in an enzyme-linked immunosorbent assay, for cytotoxic activity, in ADCC and CMAC, against eye muscle and thyroid cells. All monoclonal antibodies were of the IgM class and negative in ADCC assays. When tested in CMAC against eye muscle cells, one of 9 mouse and 5 of 8 human monoclonal antibodies showed significant activity while tests were positive in one of 9 and one of 10 monoclonal antibodies

  15. PF4-HIT antibody (KKO) complexes activate broad innate immune and inflammatory responses.

    Science.gov (United States)

    Haile, Lydia A; Rao, Roshni; Polumuri, Swamy K; Arepally, Gowthami M; Keire, David A; Verthelyi, Daniela; Sommers, Cynthia D

    2017-11-01

    Heparin-induced thrombocytopenia (HIT) is an immune-mediated complication of heparin anticoagulation therapy resulting in thrombocytopenia frequently accompanied by thrombosis. Current evidence suggests that HIT is associated with antibodies developed in response to multi-molecular complexes formed by platelet factor 4 (PF4) bound to heparin or cell surface glycosaminoglycans. These antibody complexes activate platelets and monocytes typically through FcγRIIA receptors increasing the production of PF4, inflammatory mediators, tissue factor and thrombin. The influence of underlying events in HIT including complex-induced pro-inflammatory cell activation and structural determinants leading to local inflammatory responses are not fully understood. The stoichiometry and complex component requirements were determined by incubating fresh peripheral blood mononuclear cells (PBMC) with different concentrations of unfractionated heparin (H), low molecular weight heparin (LMWH), PF4- and anti-PF4-H complex antibodies (KKO). Cytokine mRNA or protein were measured by qRT-PCR or Meso Scale Discovery technology, respectively. Gene expression profile analysis for 594 genes was performed using Nanostring technology and analyzed using Ingenuity Pathway Analysis software. The data show that antibodies magnify immune responses induced in PBMCs by PF4 alone or in complex with heparin or LMWH. We propose that following induction of HIT antibodies by heparin-PF4 complexes, binding of the antibodies to PF4 is sufficient to induce a local pro-inflammatory response which may play a role in the progression of HIT. In vitro assays using PBMCs may be useful in characterizing local inflammatory and innate immune responses induced by HIT antibodies in the presence of PF4 and different sources of heparins. The findings and conclusions in this article are solely the responsibility of the authors and are not being formally disseminated by the Food and Drug Administration. Thus, they should not be

  16. Triiodothyronine improves the primary antibody response to sheep red blood cells in severely undernourished weanling mice

    International Nuclear Information System (INIS)

    Filteau, S.M.; Perry, K.J.; Woodward, B.

    1987-01-01

    Three experiments were conducted in which weanling mice were fed a nutritionally complete diet either ad libitum or in restricted quantities such that they lost about 30% of their initial weight over a 14-day period. In Experiments 1 and 2, half the animals from each group received dietary triiodothyronine (T 3 ) supplements. In Experiment 3, food-intake-restricted mice were fed graded levels of potassium iodide. Malnutrition reduced the number of nucleated cells per spleen, the number of splenic IgG plaque-forming cells (PFC) per 10 6 cells, and the serum antibody titers against sheep red blood cells as determined by radioimmunoassay. T 3 supplements increased antibody titers, the number of nucleated cells per spleen, and both IgM and IgG PFC per 10 6 spleen cells in malnourished mice, but had no effect on well-nourished mice. The beneficial effect of T 3 was not a result of improved protein, energy, or iodine status in the malnourished mice

  17. Specific Monoclonal Antibody Overcomes the Salmonella enterica Serovar Typhimurium's Adaptive Mechanisms of Intramacrophage Survival and Replication.

    Directory of Open Access Journals (Sweden)

    Swarmistha Devi Aribam

    Full Text Available Salmonella-specific antibodies play an important role in host immunity; however, the mechanisms of Salmonella clearance by pathogen-specific antibodies remain to be completely elucidated since previous studies on antibody-mediated protection have yielded inconsistent results. These inconsistencies are at least partially attributable to the use of polyclonal antibodies against Salmonella antigens. Here, we developed a new monoclonal antibody (mAb-449 and identified its related immunogen that protected BALB/c mice from infection with Salmonella enterica serovar Typhimurium. In addition, these data indicate that the mAb-449 immunogen is likely a major protective antigen. Using in vitro infection studies, we also analyzed the mechanism by which mAb-449 conferred host protection. Notably, macrophages infected with mAb-449-treated S. Typhimurium showed enhanced pathogen uptake compared to counterparts infected with control IgG-treated bacteria. Moreover, these macrophages produced elevated levels of pro-inflammatory cytokine TNFα and nitric oxide, indicating that mAb-449 enhanced macrophage activation. Finally, the number of intracellular bacteria in mAb-449-activated macrophages decreased considerably, while the opposite was found in IgG-treated controls. Based on these findings, we suggest that, although S. Typhimurium has the potential to survive and replicate within macrophages, host production of a specific antibody can effectively mediate macrophage activation for clearance of intracellular bacteria.

  18. Neutralizing Antibodies and Pathogenesis of Hepatitis C Virus Infection

    Directory of Open Access Journals (Sweden)

    Françoise Stoll-Keller

    2012-10-01

    Full Text Available Hepatitis C virus (HCV infection is a major cause of chronic liver disease worldwide. The interplay between the virus and host innate and adaptive immune responses determines the outcome of infection. There is increasing evidence that host neutralizing responses play a relevant role in the resulting pathogenesis. Furthermore, viral evasion from host neutralizing antibodies has been revealed to be an important contributor in leading both to viral persistence in acute liver graft infection following liver transplantation, and to chronic viral infection. The development of novel model systems to study HCV entry and neutralization has allowed a detailed understanding of the molecular mechanisms of virus-host interactions during antibody-mediated neutralization. The understanding of these mechanisms will ultimately contribute to the development of novel antiviral preventive strategies for liver graft infection and an urgently needed vaccine. This review summarizes recent concepts of the role of neutralizing antibodies in viral clearance and protection, and highlights consequences of viral escape from neutralizing antibodies in the pathogenesis of HCV infection.

  19. Generation and Characterization of Novel Human IRAS Monoclonal Antibodies

    Directory of Open Access Journals (Sweden)

    Bo Wang

    2009-01-01

    Full Text Available Imidazoline receptors were first proposed by Bousquet et al., when they studied antihypertensive effect of clonidine. A strong candidate for I1R, known as imidazoline receptor antisera-selected protein (IRAS, has been cloned from human hippocampus. We reported that IRAS mediated agmatine-induced inhibition of opioid dependence in morphine-dependent cells. To elucidate the functional and structure properties of I1R, we developed the newly monoclonal antibody against the N-terminal hIRAS region including the PX domain (10–120aa through immunization of BALB/c mice with the NusA-IRAS fusion protein containing an IRAS N-terminal (10–120aa. Stable hybridoma cell lines were established and monoclonal antibodies specifically recognized full-length IRAS proteins in their native state by immunoblotting and immunoprecipitation. Monoclonal antibodies stained in a predominantly punctate cytoplasmic pattern when applied to IRAS-transfected HEK293 cells by indirect immunofluorescence assays and demonstrated excellent reactivity in flow immunocytometry. These monoclonal antibodies will provide powerful reagents for the further investigation of hIRAS protein functions.

  20. An acute hemolytic transfusion reaction due to the "anti-c" rhesus antibody: A case report emphasizing the role of transfusion medicine

    Directory of Open Access Journals (Sweden)

    Deepti Sachan

    2015-01-01

    Full Text Available Rhesus (Rh mediated hemolytic transfusion reactions (HTR are usually immunoglobulin G mediated and delayed onset. Rh antibodies being the cause of acute HTR (AHTR and intravascular hemolysis are still under debate. We report here a case of a 53-year-old male who developed AHTR due to "anti-c" antibodies within 3 h of blood transfusion, precipitating fatal acute liver failure in a patient with hepatitis C related chronic liver disease. This case emphasizes the need of inclusion of antibody screening in routine pretransfusion testing as well as a critical role of transfusion medicine specialists for early diagnosis and minimizing transfusion-related morbidity and mortality.

  1. Monoclonal antibodies and toxins--a perspective on function and isotype.

    Science.gov (United States)

    Chow, Siu-Kei; Casadevall, Arturo

    2012-06-01

    Antibody therapy remains the only effective treatment for toxin-mediated diseases. The development of hybridoma technology has allowed the isolation of monoclonal antibodies (mAbs) with high specificity and defined properties, and numerous mAbs have been purified and characterized for their protective efficacy against different toxins. This review summarizes the mAb studies for 6 toxins--Shiga toxin, pertussis toxin, anthrax toxin, ricin toxin, botulinum toxin, and Staphylococcal enterotoxin B (SEB)--and analyzes the prevalence of mAb functions and their isotypes. Here we show that most toxin-binding mAbs resulted from immunization are non-protective and that mAbs with potential therapeutic use are preferably characterized. Various common practices and caveats of protection studies are discussed, with the goal of providing insights for the design of future research on antibody-toxin interactions.

  2. Diagnostic Utility of Auto-Antibodies in Inflammatory Muscle Diseases.

    Science.gov (United States)

    Allenbach, Y; Benveniste, O

    2015-01-01

    To date, there are four main groups of idiopathic inflammatory myopathies (IIM): polymyositis (PM), dermatomyositis (DM), immune-mediated necrotizing myopathy (IMNM) and sporadic inclusion body myositis; based on clinical presentation and muscle pathology. Nevertheless, important phenotypical differences (either muscular and/or extra-muscular manifestations) within a group persist. In recent years, the titration of different myositis-specific (or associated) auto-antibodies as a diagnostic tool has increased. This is an important step forward since it may facilitate, at a viable cost, the differential diagnosis between IIM and other myopathies. We have now routine access to assays for the detection of different antibodies. For example, IMNM are related to the presence of anti-SRP or anti-HMGCR. PM is associated with anti-synthetase antibodies (anti-Jo-1, PL-7, PL-12, OJ, and EJ) and DM with anti-Mi-2, anti-SAE, anti-TIF-1-γ and anti-NXP2 (both associated with cancer) or anti-MDA5 antibodies (associated with interstitial lung disease). Today, over 30 myositis specific and associated antibodies have been characterised, and all groups of myositis may present one of those auto-antibodies. Most of them allow identification of homogenous patient groups, more precisely than the classical international classifications of myositis. This implies that classification criteria could be modified accordingly, since these auto-antibodies delineate groups of patients suffering from myositis with consistent clinical phenotype (muscular and extra-muscular manifestations), common prognostic (cancer association, presence of interstitial lung disease, mortality and risk of relapse) and treatment responses. Nevertheless, since numerous auto-antibodies have been recently characterised, the exact prevalence of myositis specific antibodies remains to be documented, and research of new auto-antibodies in the remaining seronegative group is still needed.

  3. Fc engineering of anti-Nectin-2 antibody improved thrombocytopenic adverse event in monkey.

    Directory of Open Access Journals (Sweden)

    Tsutomu Oshima

    Full Text Available Nectin-2 is a transmembrane glycoprotein which is involved in the process of Ca2+-independent cell-cell adhesion. In our previous study, we have demonstrated that Nectin-2 is over-expressed in breast and ovarian cancer tissues by using gene expression analysis and immunohistochemistry. Furthermore, we discovered multiple anti-Nectin-2 fully human monoclonal antibodies which inhibited tumor growth in in vivo subcutaneous xenograft models with antibody-dependent cellular cytotoxicity (ADCC as the principal mechanism of action. In this report, we assessed the toxicity of Y-443, a fully human IgG1/kappa anti-Nectin-2 monoclonal antibody exhibiting strong in vitro ADCC and in vivo anti-tumor activity in cynomolgus monkeys (Macaca fascicularis (Cynos. Unexpectedly, upon administration, Y-443 induced strong thrombocytopenia through Nectin-2 expressed on Cyno platelets, presumably followed by phagocytosis in the mononuclear phagocytic system. To mitigate the adverse safety profile, we mutated the Fc region of Y-443 to reduce the Fc binding activity to Fcγ receptor I, which is the primary receptor for phagocytosis on macrophages. Moreover, we further engineered the Fc through defucosylation to maintain ADCC activity. The resultant Fc engineered antibody, termed Y-634, demonstrated diminished thrombocytopenia in Cyno toxicological studies and maintained anti-tumor activity in a mouse xenograft model. These findings suggest that Y-634 may have a therapeutic potential for the treatment of Nectin-2 positive cancers, and moreover, Fc engineering is a potential mitigation strategy to ameliorate safety liabilities in antibody induced thrombocytopenia while maintaining antibody potency.

  4. Targeted in vivo inhibition of specific protein-protein interactions using recombinant antibodies.

    Directory of Open Access Journals (Sweden)

    Matej Zábrady

    Full Text Available With the growing availability of genomic sequence information, there is an increasing need for gene function analysis. Antibody-mediated "silencing" represents an intriguing alternative for the precise inhibition of a particular function of biomolecules. Here, we describe a method for selecting recombinant antibodies with a specific purpose in mind, which is to inhibit intrinsic protein-protein interactions in the cytosol of plant cells. Experimental procedures were designed for conveniently evaluating desired properties of recombinant antibodies in consecutive steps. Our selection method was successfully used to develop a recombinant antibody inhibiting the interaction of ARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEIN 3 with such of its upstream interaction partners as the receiver domain of CYTOKININ INDEPENDENT HISTIDINE KINASE 1. The specific down-regulation of the cytokinin signaling pathway in vivo demonstrates the validity of our approach. This selection method can serve as a prototype for developing unique recombinant antibodies able to interfere with virtually any biomolecule in the living cell.

  5. Serum antibody responses in pigs trickle-infected with Ascaris and Trichuris

    DEFF Research Database (Denmark)

    Kringel, Helene; Thamsborg, Stig Milan; Petersen, Heidi Huus

    2015-01-01

    A humoral immune response following helminth infection in pigs is well documented. However, it has been difficult to confirm the existence of antibody mediated resistance against the large roundworm, Ascaris suum, and whipworm, Trichuris suis, in experimental settings by correlating worm burdens...... or egg excretion with specific antibody levels. We set out to investigate the association between worm load and T. suis and A. suum specific serum antibody levels (IgG1, IgG2 and IgA) against excretory-secretory products of adults and third stage larvae, respectively, measured at 0, 7 and 14 weeks p.......i. in a trickle-infected F1-resource-population of crossbred pigs (n=195). Furthermore, we wanted to determine the heritability of these antibody isotypes during the course of infection. Most pigs remained infected with A. suum throughout the experiment while they expelled T. suis between 7 and 14 weeks post...

  6. LC-MS/MS strategies for therapeutic antibodies and investigation into the quantitative impact of antidrug-antibodies.

    Science.gov (United States)

    Ewles, Matthew; Mannu, Ranbir; Fox, Chris; Stanta, Johannes; Evans, Graeme; Goodwin, Lee; Duffy, James; Bell, Len; Estdale, Sian; Firth, David

    2016-12-01

    We aimed to establish novel, high-throughput LC-MS/MS strategies for quantification of monoclonal antibodies in human serum and examine the potential impact of antidrug antibodies. We present two strategies using a thermally stable immobilized trypsin. The first strategy uses whole serum digestion and the second introduces Protein G enrichment to improve the selectivity. The impact of anti-trastuzumab antibodies on the methods was tested. Whole serum digestion has been validated for trastuzumab (LLOQ 0.25 µg/ml). Protein G enrichment has been validated for trastuzumab (LLOQ 0.1 µg/ml), bevacizumab (LLOQ 0.1 µg/ml) and adalimumab (LLOQ 0.25 µg/ml). We have shown the potential for anti-drug antibodies to impact on the quantification and we have subsequently established a strategy to overcome this impact where total quantification is desired.

  7. Improvements in or relating to antibodies active against human hemoglobin Asub(1C)

    International Nuclear Information System (INIS)

    Javid, J.; Cerami, A.; Koenig, R.J.; Pettis, P.K.

    1980-01-01

    A method is described for preparing an antibody against human hemoglobin Asub(1c) which is substantially free of cross-reactivity against the human hemoglobins A 0 , Asub(1a) and Asub(1b). The antibodies are collected from cats, goats or sheep following injections of purified hemoglobin Asub(1c) antigen since these animals do not naturally produce hemoglobin Asub(1c). A radioimmunoassay method is also described whereby these antibodies are used to determine the quantity of hemoglobin Asub(1c) in blood samples. This is a useful technique in the diagnosis of diabetes mellitus. (U.K.)

  8. The impact of pretransplant donor-specific antibodies on graft outcome in renal transplantation: a six-year follow-up study

    Directory of Open Access Journals (Sweden)

    Elias David-Neto

    2012-01-01

    Full Text Available OBJECTIVE: The significance of pretransplant, donor-specific antibodies on long-term patient outcomes is a subject of debate. This study evaluated the impact and the presence or absence of donor-specific antibodies after kidney transplantation on short- and long-term graft outcomes. METHODS: We analyzed the frequency and dynamics of pretransplant donor-specific antibodies following renal transplantation from a randomized trial that was conducted from 2002 to 2004 and correlated these findings with patient outcomes through 2009. Transplants were performed against a complement-dependent T- and B-negative crossmatch. Pre- and posttransplant sera were available from 94 of the 118 patients (80%. Antibodies were detected using a solid-phase (LuminexH, single-bead assay, and all tests were performed simultaneously. RESULTS: Sixteen patients exhibited pretransplant donor-specific antibodies, but only 3 of these patients (19% developed antibody-mediated rejection and 2 of them experienced early graft losses. Excluding these 2 losses, 6 of 14 patients exhibited donor-specific antibodies at the final follow-up exam, whereas 8 of these patients (57% exhibited complete clearance of the donor-specific antibodies. Five other patients developed ''de novo'' posttransplant donor-specific antibodies. Death-censored graft survival was similar in patients with pretransplant donor-specific and non-donor-specific antibodies after a mean follow-up period of 70 months. CONCLUSION: Pretransplant donor-specific antibodies with a negative complement-dependent cytotoxicity crossmatch are associated with a risk for the development of antibody-mediated rejection, although survival rates are similar when patients transpose the first months after receiving the graft. Our data also suggest that early posttransplant donor-specific antibody monitoring should increase knowledge of antibody dynamics and their impact on long-term graft outcome.

  9. Effect of kinase inhibitors on the therapeutic properties of monoclonal antibodies.

    Science.gov (United States)

    Duong, Minh Ngoc; Matera, Eva-Laure; Mathé, Doriane; Evesque, Anne; Valsesia-Wittmann, Sandrine; Clémenceau, Béatrice; Dumontet, Charles

    2015-01-01

    Targeted therapies of malignancies currently consist of therapeutic monoclonal antibodies and small molecule kinase inhibitors. The combination of these novel agents raises the issue of potential antagonisms. We evaluated the potential effect of 4 kinase inhibitors, including the Bruton tyrosine kinase inhibitor ibrutinib, and 3 PI3K inhibitors idelalisib, NVP-BEZ235 and LY294002, on the effects of the 3 monoclonal antibodies, rituximab and obinutuzumab (directed against CD20) and trastuzumab (directed against HER2). We found that ibrutinib potently inhibits antibody-dependent cell-mediated cytotoxicity exerted by all antibodies, with a 50% inhibitory concentration of 0.2 microM for trastuzumab, 0.5 microM for rituximab and 2 microM for obinutuzumab, suggesting a lesser effect in combination with obinutuzumab than with rituximab. The 4 kinase inhibitors were found to inhibit phagocytosis by fresh human neutrophils, as well as antibody-dependent cellular phagocytosis induced by the 3 antibodies. Conversely co-administration of ibrutinib with rituximab, obinutuzumab or trastuzumab did not demonstrate any inhibitory effect of ibrutinib in vivo in murine xenograft models. In conclusion, some kinase inhibitors, in particular, ibrutinib, are likely to exert inhibitory effects on innate immune cells. However, these effects do not compromise the antitumor activity of monoclonal antibodies in vivo in the models that were evaluated.

  10. Bronchial asthma is not associated with auto-antibodies to lipocortin-1.

    Science.gov (United States)

    Wilkinson, J R; Podgorski, M R; Godolphin, J L; Goulding, N J; Lee, T H

    1990-03-01

    Corticosteroids may mediate some of their anti-inflammatory action by the induction of lipocortin-1, which inhibits phospholipase A2 activity. Raised levels of antibodies to lipocortin have been found in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) and it has been postulated that these may contribute to steroid resistance. A proportion of asthmatic patients fail to respond to treatment with corticosteroids and one possible mechanism is that these patients have raised levels of anti-lipocortin antibodies. We have therefore measured IgG and IgM antibodies to lipocortin by enzyme linked immunosorbent assay (ELISA) in eight corticosteroid-sensitive (CS) and 7 corticosteroid-resistant (CR) asthmatic subjects, and in eight normal controls. Comparison of asthmatic subjects with normal controls revealed no significant differences in either IgG or IgM antibodies to lipocortin. Comparison of CS asthmatic subjects with CR asthmatic subjects similarly revealed no significant differences in the concentration of either IgG or IgM antibodies to lipocortin. Levels of anti-lipocortin antibodies did not correlate with clinical response to treatment with 40 mg/day of prednisolone. Anti-lipocortin antibodies are unlikely to be involved in the inflammation seen in asthma, or in the relative insensitivity to corticosteroids seen in CR asthmatic subjects.

  11. Antigen-targeting strategies using single-domain antibody fragments

    NARCIS (Netherlands)

    Duarte, Joao Nuno Silva

    2017-01-01

    Antibodies display high selectivity and affinity and have been the preferred platform for antigen targeting. Despite the development of antigen-delivery systems that enable T cell activation, targeting approaches that enhance antibody responses need improvement. This need specially applies to poorly

  12. Reactive Oxygen Species-Mediated Mechanisms of Action of Targeted Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Hanna-Riikka Teppo

    2017-01-01

    Full Text Available Targeted cancer therapies, involving tyrosine kinase inhibitors and monoclonal antibodies, for example, have recently led to substantial prolongation of survival in many metastatic cancers. Compared with traditional chemotherapy and radiotherapy, where reactive oxygen species (ROS have been directly linked to the mediation of cytotoxic effects and adverse events, the field of oxidative stress regulation is still emerging in targeted cancer therapies. Here, we provide a comprehensive review regarding the current evidence of ROS-mediated effects of antibodies and tyrosine kinase inhibitors, use of which has been indicated in the treatment of solid malignancies and lymphomas. It can be concluded that there is rapidly emerging evidence of ROS-mediated effects of some of these compounds, which is also relevant in the context of drug resistance and how to overcome it.

  13. [International classification of various types of monoclonal antibodies].

    Science.gov (United States)

    Scheen, A J

    2009-01-01

    Significant advances in the development of monoclonal antibodies ("mabs") have been acknowledged during the last two decades. Successive developments led to the marketing of murine antibodies ("o-mab" first, followed by chimeric antibodies ("xi-mab"), humanised antibodies ("zu-mab") and, finally, human monoclonal antibodies ("u-mab"). In order to facilitate the distinction between the various monoclonal antibodies used in clinical practice, an international nomenclature has been proposed with the use of a specific suffix corresponding to the origine/source of "mabs" preceded by an infix referring to the medicine's target. The efforts in developing new types of monoclonal antibodies aimed at improving their pharmacokinetics (longer half-life), pharmacodynamics (better efficacy because of stronger affinity to human receptor), and safety profile (less antigenic and immunogenic reactions). These progresses could be obtained thanks to the remarkable development of molecular biotechnology.

  14. Focal status epilepticus and progressive dyskinesia: A novel phenotype for glycine receptor antibody-mediated neurological disease in children.

    Science.gov (United States)

    Chan, D W S; Thomas, T; Lim, M; Ling, S; Woodhall, M; Vincent, A

    2017-03-01

    Antibody-associated disorders of the central nervous system are increasingly recognised in adults and children. Some are known to be paraneoplastic, whereas in others an infective trigger is postulated. They include disorders associated with antibodies to N-methyl-d-aspartate receptor (NMDAR), voltage-gated potassium channel-complexes (VGKC-complex), GABA B receptor or glycine receptor (GlyR). With antibodies to NMDAR or VGKC-complexes, distinct clinical patterns are well characterised, but as more antibodies are discovered, the spectra of associated disorders are evolving. GlyR antibodies have been detected in patients with progressive encephalopathy with rigidity and myoclonus (PERM), or stiff man syndrome, both rare but disabling conditions. We report a case of a young child with focal seizures and progressive dyskinesia in whom GlyR antibodies were detected. Anticonvulsants and immunotherapy were effective in treating both the seizures and movement disorder with good neurological outcome and with a decline in the patient's serum GlyR-Ab titres. Glycine receptor antibodies are associated with focal status epilepticus and seizures, encephalopathy and progressive dyskinesia and should be evaluated in autoimmune encephalitis. Copyright © 2016 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  15. Annual literature review of donor-specific HLA antibodies after organ transplantation.

    Science.gov (United States)

    Kaneku, Hugo

    2011-01-01

    The literature review of post-transplant DSA published in 2011 shows: Observations after kidney and lung transplant in non-sensitized transplant recipients show that monitoring post-transplant HLA antibodies offers limited benefit in predicting acute rejection episodes. It remains to be seen if a different monitoring schedule and/ or studying other organs may show otherwise. Nevertheless, others have shown that monitoring post-transplant antibodies does identify patients at higher risk for chronic rejection. Studies in kidney, heart, and liver patients transplanted in the presence of preformed DSA show that detecting these antibodies early after transplant identifies a group of patients with greater risk for allograft dysfunction. New and larger studies using bortezomib and eculizumab to treat acute antibody-mediated rejection confirm earlier observations that these two therapies are effective in treating and preventing rejections. In general, identification of HLAantibodies and DSA after transplant is associated with higher rates of rejection and poor allograft survival in all organs examined. IgM antibodies appear to play an important role after lung transplants.

  16. Improvement of macrophage dysfunction by administration of anti-transforming growth factor-beta antibody in EL4-bearing hosts.

    Science.gov (United States)

    Maeda, H; Tsuru, S; Shiraishi, A

    1994-11-01

    An experimental therapy for improvement of macrophage dysfunction caused by transforming growth factor-beta (TGF-beta) was tried in EL4 tumor-bearing mice. TGF-beta was detected in cell-free ascitic fluid from EL4-bearers, but not in that from normal mice, by western blot analysis. The ascites also showed growth-suppressive activity against Mv1Lu cells, and the suppressive activity was potentiated by transient acidification. To investigate whether the functions of peritoneal macrophages were suppressed in EL4-bearers, the abilities to produce nitric oxide and tumor necrosis factor-alpha (TNF-alpha) upon lipopolysaccharide (LPS) stimulation were measured. Both abilities of macrophages in EL4-bearing mice were suppressed remarkably on day 9, and decreased further by day 14, compared with non-tumor-bearing controls. TGF-beta activity was abrogated by administration of anti-TGF-beta antibody to EL4-bearing mice. While a large amount of TGF-beta was detected in ascitic fluid from control EL4-bearers, little TGF-beta was detectable in ascites from EL4-bearers given anti-TGF-beta antibody. Furthermore, while control macrophages exhibited little or no production of nitric oxide and TNF-alpha on LPS stimulation in vitro, macrophages from EL4-bearers administered with anti-TGF-beta antibody showed the same ability as normal macrophages. These results clearly indicate that TGF-beta contributes to macrophage dysfunction and that the administration of specific antibody for TGF-beta reverses macrophage dysfunction in EL4-bearing hosts.

  17. The role of HLA antibodies in allogeneic SCT: is the 'type-and-screen' strategy necessary not only for blood type but also for HLA?

    Science.gov (United States)

    Yoshihara, S; Taniguchi, K; Ogawa, H; Saji, H

    2012-12-01

    The role of HLA antibodies in SCT has drawn increasing attention because of the significantly increased number of patients who receive HLA-mismatched SCT, including cord blood transplantation, haploidentical SCT and unrelated SCT. Technical advancements in the methods of HLA Ab testing have realized rapid, accurate and objective identification, as well as quantification of specific HLA antibodies. Recent clinical studies have suggested that the presence of donor-specific HLA antibodies (DSA) in patients is associated with graft failure in HLA-mismatched SCT when the above-listed stem cell sources are used and results in different impacts. Of note, most of the 'HLA-matched' unrelated SCT actually involve HLA mismatches in HLA-DP and the presence of antibodies against this locus has been reported to be associated with graft failure. Thus, HLA Ab should be examined as a work-up for all patients who undergo SCT from 'alternative donors.' The simplest route for preventing HLA Ab-mediated graft failure in Ab-positive patients is to avoid donors who possess the target Ag of HLA antibodies. If SCT from such donors must be performed, treatment for DSA before SCT may improve the chances of successful donor engraftment.

  18. Next Generation Antibody Therapeutics Using Bispecific Antibody Technology.

    Science.gov (United States)

    Igawa, Tomoyuki

    2017-01-01

    Nearly fifty monoclonal antibodies have been approved to date, and the market for monoclonal antibodies is expected to continue to grow. Since global competition in the field of antibody therapeutics is intense, we need to establish novel antibody engineering technologies to provide true benefit for patients, with differentiated product values. Bispecific antibodies are among the next generation of antibody therapeutics that can bind to two different target antigens by the two arms of immunoglobulin G (IgG) molecule, and are thus believed to be applicable to various therapeutic needs. Until recently, large scale manufacturing of human IgG bispecific antibody was impossible. We have established a technology, named asymmetric re-engineering technology (ART)-Ig, to enable large scale manufacturing of bispecific antibodies. Three examples of next generation antibody therapeutics using ART-Ig technology are described. Recent updates on bispecific antibodies against factor IXa and factor X for the treatment of hemophilia A, bispecific antibodies against a tumor specific antigen and T cell surface marker CD3 for cancer immunotherapy, and bispecific antibodies against two different epitopes of soluble antigen with pH-dependent binding property for the elimination of soluble antigen from plasma are also described.

  19. Radioimmunoassay with heterologous antibody (hetero-antibody RIA)

    International Nuclear Information System (INIS)

    Iwasawa, Atsushi; Hayashi, Hiroaki; Itoh, Zen; Wakabayashi, Katsumi

    1991-01-01

    To develop a homologous radioimmunoassay (RIA) for a hormone of a small or rare animal often meets difficulty in collecting a large amount of purified antigen required for antibody production. On the other hand, to employ a heterologous RIA to estimate the hormone often gives poor sensitivity. To overcome this difficulty, a 'hetero-antibody' RIA was studied. In a hetero-antibody RIA system, a purified preparation of a hormone is used for radioiodination and standardization and a heterologous antibody to the hormone is used for the first antibody. Canine motilin and rat LH were selected as examples, and anti-porcine motilin and anti-hCG, anti-hCGβ or anti-ovine LHβ was used as the heterologous antibody. The sensitivities of the hetero-antibody RIAs were much higher than those of heterologous RIAs in any case, showing that these hetero-antibody RIA systems were suitable for practical use. To clarify the principle of hetero-antibody RIA, antiserum to porcine motilin was fractionated on an affinity column where canine motilin was immobilized. The fraction bound had greater constants of affinity with both porcine and canine motilins than the rest of the antibody fractions. This fraction also reacted with a synthetic peptide corresponding to the C-terminal sequence common to porcine and canine motilins in a competitive binding test with labeled canine motilin. These results suggest that an antibody population having high affinity and cross-reactivity is present in polyclonal antiserum and indicate that the population can be used in hetero-antibody RIA at an appropriate concentration. (author)

  20. Antibodies and Selection of Monoclonal Antibodies.

    Science.gov (United States)

    Hanack, Katja; Messerschmidt, Katrin; Listek, Martin

    Monoclonal antibodies are universal binding molecules with a high specificity for their target and are indispensable tools in research, diagnostics and therapy. The biotechnological generation of monoclonal antibodies was enabled by the hybridoma technology published in 1975 by Köhler and Milstein. Today monoclonal antibodies are used in a variety of applications as flow cytometry, magnetic cell sorting, immunoassays or therapeutic approaches. First step of the generation process is the immunization of the organism with appropriate antigen. After a positive immune response the spleen cells are isolated and fused with myeloma cells in order to generate stable, long-living antibody-producing cell lines - hybridoma cells. In the subsequent identification step the culture supernatants of all hybridoma cells are screened weekly for the production of the antibody of interest. Hybridoma cells producing the antibody of interest are cloned by limited dilution till a monoclonal hybridoma is found. This is a very time-consuming and laborious process and therefore different selection strategies were developed since 1975 in order to facilitate the generation of monoclonal antibodies. Apart from common automation of pipetting processes and ELISA testing there are some promising approaches to select the right monoclonal antibody very early in the process to reduce time and effort of the generation. In this chapter different selection strategies for antibody-producing hybridoma cells are presented and analysed regarding to their benefits compared to conventional limited dilution technology.

  1. Improvement of western blot test specificity for detecting equine serum antibodies to Sarcocystis neurona.

    Science.gov (United States)

    Rossano, M G; Mansfield, L S; Kaneene, J B; Murphy, A J; Brown, C M; Schott, H C; Fox, J C

    2000-01-01

    Equine protozoal myeloencephalitis (EPM) is a neurological disease of horses and ponies caused by the apicomplexan protozoan parasite Sarcocystis neurona. The purposes of this study were to develop the most stringent criteria possible for a positive test result, to estimate the sensitivity and specificity of the EPM Western blot antibody test, and to assess the ability of bovine antibodies to Sarcocystis cruzi to act as a blocking agent to minimize false-positive results in the western blot test for S. neurona. Sarcocystis neurona merozoites harvested from equine dermal cell culture were heat denatured, and the proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in a 12-20% linear gradient gel. Separated proteins were electrophoretically transferred to polyvinylidene fluoride membranes and blocked in 1% bovine serum albumin and 0.5% Tween-Tris-buffered saline. Serum samples from 6 horses with S. neurona infections (confirmed by culture from neural tissue) and 57 horses without infections (horses from the Eastern Hemisphere, where S. neurona does not exist) were tested by Western blot. Horses from both groups had reactivity to the 62-, 30-, 16-, 13-, 11-, 10.5-, and 10-kD bands. Testing was repeated with another step. Blots were treated with bovine S. cruzi antibodies prior to loading the equine samples. After this modification of the Western blot test, positive infection status was significantly associated with reactivity to the 30- and 16-kD bands (Pblot had a sample sensitivity of 100% and sample specificity of 98%. It is concluded that the specificity of the Western blot test is improved by blocking proteins not specific to S. neurona and using reactivity to the 30- and 16-kD bands as the criterion for a positive test.

  2. Structure of an isolated unglycosylated antibody CH2 domain

    International Nuclear Information System (INIS)

    Prabakaran, Ponraj; Vu, Bang K.; Gan, Jianhua; Feng, Yang; Dimitrov, Dimiter S.; Ji, Xinhua

    2008-01-01

    The crystal structure of an isolated unglycosylated antibody C H 2 domain has been determined at 1.7 Å resolution. The C H 2 (C H 3 for IgM and IgE) domain of an antibody plays an important role in mediating effector functions and preserving antibody stability. It is the only domain in human immunoglobulins (Igs) which is involved in weak interchain protein–protein interactions with another C H 2 domain solely through sugar moieties. The N-linked glycosylation at Asn297 is conserved in mammalian IgGs as well as in homologous regions of other antibody isotypes. To examine the structural details of the C H 2 domain in the absence of glycosylation and other antibody domains, the crystal structure of an isolated unglycosylated antibody γ1 C H 2 domain was determined at 1.7 Å resolution and compared with corresponding C H 2 structures from intact Fc, IgG and Fc receptor complexes. Furthermore, the oligomeric state of the protein in solution was studied using size-exclusion chromatography. The results suggested that the unglycosylated human antibody C H 2 domain is a monomer and that its structure is similar to that found in the intact Fc, IgG and Fc receptor complex structures. However, certain structural variations were observed in the Fc receptor-binding sites. Owing to its small size, stability and non-immunogenic Ig template, the C H 2-domain structure could be useful for the development by protein design of antibody domains exerting effector functions and/or antigen specificity and as a robust scaffold in protein-engineering applications

  3. Antibody Maturation in Trypanosoma cruzi-Infected Rats

    Science.gov (United States)

    Marcipar, Iván S.; Risso, Marikena G.; Silber, Ariel M.; Revelli, Silvia; Marcipar, Alberto J.

    2001-01-01

    The study of antibody avidity changes during infection has improved the understanding of the pathologic processes involved in several infectious diseases. In some infections, like toxoplasmosis, this information is being used for diagnostic purposes. Results of the evolution of antibody avidity for different specific antigens in Trypanosome cruzi-infected rats are presented. A Western blotting technique, combined with avidity analysis to identify antigens that elicit high-avidity antibodies, is suggested. In this system, antibodies showed high avidity values only during the chronic phase of infection and only in relation to antibodies against 21-, 33-, 41-, 42-, 56-, 58-, 66-, and 72-kDa antigens. Finally, a 97-kDa T. cruzi antigen, which was recognized by high-avidity antibodies and occurred in noninfected rats, was identified. These results allow us to evaluate the different antigens in chagasic infection. Our results show that with the correct choice of antigen it is possible to detect differences in maturation of antibodies and to discriminate, in an experimental model, between recent (acute) and chronic infections. PMID:11427430

  4. Functionally fused antibodies--a novel adjuvant fusion system

    DEFF Research Database (Denmark)

    Larsen, Martin; Jensen, Kim Bak; Christensen, Peter Astrup

    2008-01-01

    Antibodies capable of recognizing key molecular targets isolated e.g. by phage display technology have been used in the pursuit of new and improved therapies for prevalent human diseases. These approaches often take advantage of non-immunogenic antibody fragments to achieve specific toxin-, radio...

  5. Studies of cytotoxic antibodies against eye muscle antigens in patients with thyroid-associated ophthalmopathy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.-G.; Hiromatsu, Y.; Salvi, M.; Triller, H.; Bernard, N.; Wall, J.R. (Thyroid Research Unit, The Montreal General Hospital Research Institute, Montreal, Quebec (Canada)); Medeiros-Neto, G.; Iacona, A.; Lima, N. (Thyroid Clinic, Hospital das Clinicas, Sao Paulo (Brazil))

    1989-01-01

    We have studied the prevalence and significance of cytotoxic antibodies against human eye muscle cells, as detected in antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-mediated antibody-dependent cytotoxicity (CMAC) in {sup 51}Cr release assays, in patients with Graves' ophthalmopathy or Hashimoto's thyroiditis. A high prevalence of positive ADCC tests was found in all groups of patients with ophthalmopathy tested. Tests were positive in 64% of patients with Graves' ophthalmopathy from an area of severe iodine deficiency (Sao Paulo) and in 64% of such patients from an iodine replete area (Montreal). In patients with so-called ''euthyroid ophthalmopathy'', i.e. eye disease associated with thyroiditis, ADCC tests were positive in 75 and 38% of patients from the two areas, respectively, while tests were positive in 40 and 22%, respectively, of patients with Graves' hyperthyroidism without evident eye disease. In normal subjects, levels of {sup 51}Cr release was always at background levels. In a group of patients from the high-iodine area, levels of antibodies in ADCC correlated positively with the intraocular pressure (mmHg) in primary position as a parameter of eye muscle dysfunction. In patients with ophthalmopathy, positive ADCC tests were assciated with antibodies to eye muscle membrane antigens of 55,65 and 95 kD as detected by immunoblotting, although the correlation was not close for any antigen. in contrast, CMAC tests were negative in all patients with ophthalmopathy. We also tested 9 mouse and 10 human monoclonal antibodies, reactive with orbital antigens in an enzyme-linked immunosorbent assay, for cytotoxic activity, in ADCC and CMAC, against eye muscle and thyroid cells. All monoclonal antibodies were of the IgM class and negative in ADCC assays. (Abstract Truncated)

  6. Monoclonal Antibodies and Toxins—A Perspective on Function and Isotype

    Directory of Open Access Journals (Sweden)

    Siu-Kei Chow

    2012-06-01

    Full Text Available Antibody therapy remains the only effective treatment for toxin-mediated diseases. The development of hybridoma technology has allowed the isolation of monoclonal antibodies (mAbs with high specificity and defined properties, and numerous mAbs have been purified and characterized for their protective efficacy against different toxins. This review summarizes the mAb studies for 6 toxins—Shiga toxin, pertussis toxin, anthrax toxin, ricin toxin, botulinum toxin, and Staphylococcal enterotoxin B (SEB—and analyzes the prevalence of mAb functions and their isotypes. Here we show that most toxin-binding mAbs resulted from immunization are non-protective and that mAbs with potential therapeutic use are preferably characterized. Various common practices and caveats of protection studies are discussed, with the goal of providing insights for the design of future research on antibody-toxin interactions.

  7. Monoclonal Antibodies and Toxins—A Perspective on Function and Isotype

    Science.gov (United States)

    Chow, Siu-Kei; Casadevall, Arturo

    2012-01-01

    Antibody therapy remains the only effective treatment for toxin-mediated diseases. The development of hybridoma technology has allowed the isolation of monoclonal antibodies (mAbs) with high specificity and defined properties, and numerous mAbs have been purified and characterized for their protective efficacy against different toxins. This review summarizes the mAb studies for 6 toxins—Shiga toxin, pertussis toxin, anthrax toxin, ricin toxin, botulinum toxin, and Staphylococcal enterotoxin B (SEB)—and analyzes the prevalence of mAb functions and their isotypes. Here we show that most toxin-binding mAbs resulted from immunization are non-protective and that mAbs with potential therapeutic use are preferably characterized. Various common practices and caveats of protection studies are discussed, with the goal of providing insights for the design of future research on antibody-toxin interactions. PMID:22822456

  8. Recent Advances in Monoclonal Antibody Therapies for Multiple Sclerosis

    Science.gov (United States)

    Stavropoulos, Nikolaos; Wittenberg, Nathan J.; Dasari, Harika; Abdelrahim, Murtada A.; Henley, John R.; Oh, Sang-Hyun; Warrington, Arthur E.; Rodriguez, Moses

    2016-01-01

    Introduction Multiple sclerosis (MS) is the most common chronic inflammatory, demyelinating disease of the CNS and results in neurological disability. Existing immunomodulatory and immunosuppressive approaches lower the number of relapses but do not cure or reverse existing deficits nor improve long-term disability in MS patients. Areas Covered Monogenic antibodies were described as treatment options for MS, however the immunogenicity of mouse antibodies hampered the efficacy of potential therapeutics in humans. Availability of improved antibody production technologies resulted in a paradigm shift in MS treatment strategies. In this review, an overview of immunotherapies for MS that use conventional monoclonal antibodies reactive to immune system and their properties and mechanisms of action will be discussed, including recent advances in MS therapeutics and highlight natural autoantibodies (NAbs) that directly target CNS cells. Expert Opinion Recent challenges for MS therapy are the identification of relevant molecular and cellular targets, time frame of treatment, and antibody toxicity profiles to identify safe treatment options for MS patients. The application of monoclonal antibody therapies with better biological efficacy associated with minimum side effects possesses huge clinical potential. Advances in monoclonal antibody technologies that directly target cells of nervous system may promote the CNS regeneration field from bench to bedside. PMID:26914737

  9. [Noopept improves the spatial memory and stimulates prefibrillar beta-amyloid(25-35) antibody production in mice].

    Science.gov (United States)

    Bobkova, N V; Gruden', M A; Samokhin, A N; Medvinskaia, N I; Morozova-Roch, L; Uudasheva, T A; Ostrovskaia, R U; Seredinin, S B

    2005-01-01

    The effects of the novel proline-containing nootropic and neuroprotective dipeptide noopept (GVS-111, N-phenylacetyl-L-prolylglycine ethyl ester) were studied on NMRI mice upon olfactory bulbectomy, which had been previously shown to imitate the main morphological and biochemical signs of Alzheimer's disease (AD). The spatial memory was assessed using the Morris (water maze) test; the immunological status was characterized by ELISA with antibodies to prefibrillar beta-amyloid(25-35), S100b protein, and protofilaments of equine lysozyme, which are the molecular factors involved in the pathogenesis of AD. The control (sham-operated) animals during the Morris test preferred a sector where the safety platform was placed during the learning session. Bulbectomized animals treated with saline failed to recognize this sector, while bulbectomized animals treated with noopept (0.01 mg/kg for 21 days) restored this predominance, thus demonstrating the improvement of the spatial memory. These animals also demonstrated an increase in the level of antibodies to beta-amyloid(25-35)--the effect, which was more pronounced in the sham-operated than in bulbectomized mice. The latter demonstrated a profound decrease of immunological reactivity in a large number of tests. Noopept, stimulating the production of antibodies to beta-amyloid(25-35), can attenuate the well-known neurotoxic effects of beta-amyloid. The obtained data on the mnemotropic and immunostimulant effects noopept are indicative of good prospects for the clinical usage of this drug in the therapy of patients with neurodegenerative diseases.

  10. Antibody-Based Therapies in Multiple Myeloma

    Directory of Open Access Journals (Sweden)

    Yu-Tzu Tai

    2011-01-01

    Full Text Available The unmet need for improved multiple myeloma (MM therapy has stimulated clinical development of monoclonal antibodies (mAbs targeting either MM cells or cells of the bone marrow (BM microenvironment. In contrast to small-molecule inhibitors, therapeutic mAbs present the potential to specifically target tumor cells and directly induce an immune response to lyse tumor cells. Unique immune-effector mechanisms are only triggered by therapeutic mAbs but not by small molecule targeting agents. Although therapeutic murine mAbs or chimeric mAbs can cause immunogenicity, the advancement of genetic recombination for humanizing rodent mAbs has allowed large-scale production and designation of mAbs with better affinities, efficient selection, decreasing immunogenicity, and improved effector functions. These advancements of antibody engineering technologies have largely overcome the critical obstacle of antibody immunogenicity and enabled the development and subsequent Food and Drug Administration (FDA approval of therapeutic Abs for cancer and other diseases.

  11. Neutralizing monoclonal antibodies against hepatitis C virus E2 protein bind discontinuous epitopes and inhibit infection at a postattachment step

    DEFF Research Database (Denmark)

    Sabo, Michelle C; Luca, Vincent C; Prentoe, Jannick

    2011-01-01

    The E2 glycoprotein of hepatitis C virus (HCV) mediates viral attachment and entry into target hepatocytes and elicits neutralizing antibodies in infected patients. To characterize the structural and functional basis of HCV neutralization, we generated a novel panel of 78 monoclonal antibodies (M...

  12. Reduced 99mTc labelled NCA-95/CEA-antibody uptake in liver due to gentle antibody reconstitution

    International Nuclear Information System (INIS)

    Reske, S.N.; Buell, U.

    1990-01-01

    The influence of reconstituting a murine monoclonal IgG 1 antibody kit with pertechnetate Tc99m on antibody distribution in the liver, spleen and sternal bone marrow of patients was examined. The 99m Tc-labelled antibody used is directed against non-specific cross-reacting antigen (NCA-95) and carcinoembryonic antigen (CEA) and has been successfully applied for imaging tissue inflammation and bone marrow scanning. Radioactivity uptake was determined in the liver, spleen, bone marrow and a precordial background region in a consecutive series of 25 patients, examined with an antibody preparation, routinely radiolabelled according to the manufacturer's recommendations and in 14 patients, in whom the antibody was reconstituted with special care, avoiding bubble formation and dropping of buffer into the antibody-containing vial. Gentle compared with routine antibody reconstitution caused a highly significant reduction of the antibody uptake in the liver, as determined by count densities, normalized to injected dose and acquisition time (13.2±5.5 vs 20.1±6.0 cpm per pixel, anti x±SD, P=0.008). The liver to background ratio was reduced from 3.4±1.4 to 1.9±0.5 (P<0.001). Spleen, sternal bone marrow and precordial background count rates were not significantly affected. These results clearly demonstrate that gentle antibody reconstitution can decrease non-specific antibody uptake in the liver by 34%±6.4% (anti x±SEM). Thus, scan quality is improved, and the potential deleterious camouflage of underlying structures is avoided. (orig.)

  13. Antibody-Mediated Neutralization of the Exotoxin Mycolactone, the Main Virulence Factor Produced by Mycobacterium ulcerans.

    Directory of Open Access Journals (Sweden)

    Jean-Pierre Dangy

    2016-06-01

    Full Text Available Mycolactone, the macrolide exotoxin produced by Mycobacterium ulcerans, causes extensive tissue destruction by inducing apoptosis of host cells. In this study, we aimed at the production of antibodies that could neutralize the cytotoxic activities of mycolactone.Using the B cell hybridoma technology, we generated a series of monoclonal antibodies with specificity for mycolactone from spleen cells of mice immunized with the protein conjugate of a truncated synthetic mycolactone derivative. L929 fibroblasts were used as a model system to investigate whether these antibodies can inhibit the biological effects of mycolactone. By measuring the metabolic activity of the fibroblasts, we found that anti-mycolactone mAbs can completely neutralize the cytotoxic activity of mycolactone.The toxin neutralizing capacity of anti-mycolactone mAbs supports the concept of evaluating the macrolide toxin as vaccine target.

  14. Mitogen-activated protein kinases mediate Mycobacterium ...

    Indian Academy of Sciences (India)

    2012-01-19

    Jan 19, 2012 ... CD44, an adhesion molecule, has been reported to be a binding site for ... receptors in mediating mitogen-activated protein kinase activation. ... surface expression and tumour necrosis factor-alpha levels, ... Abbreviations used: Abs, antibodies; ANOVA, analysis of variance; AP-1, activator protein -1; BCG, ...

  15. Antithyroglobulin Antibodies and Antimicrosomal Antibodies in Various Thyroid Diseases

    International Nuclear Information System (INIS)

    Lee, Gwon Jun; Hong, Key Sak; Choi, Kang Won; Lee, Kyu; Koh, Chang Soon; Lee, Mun Ho; Park, Sung Hoe; Chi, Je Geun; Lee, Sang Kook

    1979-01-01

    The authors investigated the incidence of antithyroglobulin antibodies and antibodies and antimicrosomal antibodies measured by tanned red cell hemagglutination method in subjects suffering from various thyroid disorders. 1) In 15 normal patients, neither suffering from any thyroid diseases nor from any other autoimmune disorders, the antithyroglobulin antibodies were all negative, but the antimicrosomal antibody was positive only in one patient (6.7%). 2) The antithyroglobulin antibodies were positive in 31.5% (34 patients) of 108 patients with various thyroid diseases, and the antimicrosomal antibodies were positive in 37.0% (40 patients). 3) of the 25 patients with Graves' diseases, 7 patients (28.0%) showed positive for the antithyroglobulin antibodies, and 9 (36.0%) for the antimicrosomal antibodies. There was no definite differences in clinical and thyroid functions between the groups with positive and negative results. 4) Both antibodies were positive in 16 (88.9%) and 17 (94.4%) patients respectively among 18 patients with Hashimoto's thyroiditis, all of them were diagnosed histologically. 5) Three out of 33 patients with thyroid adenoma showed positive antibodies, and 3 of 16 patients with thyroid carcinoma revealed positive antibodies. 6) TRCH antibodies demonstrated negative results in 2 patients with subacute thyroiditis, but positive in one patient with idiopathic primary myxedema. 7) The number of patients with high titers(>l:802) was 16 for antithyroglobulin antibody, and 62.5% (10 patients) of which was Hashimoto's thyroiditis. Thirteen (65.0) of 20 patients with high titers (>l:802) for antimicrosomal antibody was Hashimoto's thyroiditis. TRCH test is a simple, sensitive method, and has high reliability and reproducibility. The incidences and titers of antithyroglobulin antibody and antimicrosomal antibody are especially high in Hashimoto's thyroiditis.

  16. Antibody-mediated suppression of grafted lymphoma. III. Evaluation of the role of thymic function, non-thymus-derived lymphocytes, macrophages, platelets, and polymorphonuclear leukocytes in syngeneic and allogeneic hosts

    International Nuclear Information System (INIS)

    Shin, H.S.; Hayden, M.; Langley, S.; Kaliss, N.; Smith, M.R.

    1975-01-01

    Syngeneic or allogeneic mice pretreated with sublethal whole-body irradiation were rendered incapable of suppressing the growth of grafted tumor cells sensitized with alloantibody. The growth of sensitized tumor cells was suppressed when they were mixed with donor effector cells from mice syngeneic or allogeneic to the recipients and then were inoculated in irradiated recipients. Three donor-host combinations were used to study the suppression of the murine lymphoma 6C3HED indigenous to C3H mice. These were C3H donor cells in C3H recipients, C57BL/6 donor cells in C3H recipients, or C57BL/6 donor cells in C57BL/6 recipients. In all three combinations, macrophages obtained from an inflammatory exudate, exudate lymphocytes not bearing theta antigen, and platelets were, in descending order of effectiveness, consistently active in restoring antibody-mediated suppression of tumor growth in irradiated hosts. Prior irradiation of the transferred lymphocytes somewhat diminished their effectiveness. Freeze-thawed or heat-killed macrophages (but not freeze-thawed platelets or lymphocytes) were effective in restoration. Peripheral blood mononuclear leukocytes and splenic lymphoid cells were not active in the recipients syngeneic to the donor cells but were active in recipients allogeneic to the donor cells. Polymorphonuclear leukocytes isolated from peripheral blood or an inflammatory exudate were not active. Intact thymic function seems unimportant since antibody-mediated suppression took place as effectively in thymectomized mice as in normal controls. (U.S.)

  17. Quantitative relationship between antibody affinity and antibody avidity

    International Nuclear Information System (INIS)

    Griswold, W.R.

    1987-01-01

    The relationship between antibody avidity, measured by the dissociation of the antigen-antibody bond in antigen excess, and antibody affinity was studied. Complexes of radiolabelled antigen and antibody of known affinity were prepared in vitro and allowed to stand for seven days to reach equilibrium. Then nonlabelled antigen in one hundred fold excess was added to dissociate the complexes. After an appropriate incubation the fraction of antigen bound to antibody was measured by the ammonium sulfate precipitation method. The dissociation index was the fraction bound in the experimental sample divided by the fraction bound in the control. The correlation coefficient between the dissociation index and the antibody binding constant was 0.92 for early dissociation and 0.98 for late dissociation. The regression equation relating the binding constant to the dissociation index was K = 6.4(DI) + 6.25, where DI is the late dissociation index and K is the logarithm to the base 10 of the binding constant. There is a high correlation between avidity and affinity of antibody. Antibody affinity can be estimated from avidity data. The stability of antigen-antibody complexes can be predicted from antibody affinity

  18. Preclinical activity of the type II CD20 antibody GA101 (obinutuzumab) compared with rituximab and ofatumumab in vitro and in xenograft models.

    Science.gov (United States)

    Herter, Sylvia; Herting, Frank; Mundigl, Olaf; Waldhauer, Inja; Weinzierl, Tina; Fauti, Tanja; Muth, Gunter; Ziegler-Landesberger, Doris; Van Puijenbroek, Erwin; Lang, Sabine; Duong, Minh Ngoc; Reslan, Lina; Gerdes, Christian A; Friess, Thomas; Baer, Ute; Burtscher, Helmut; Weidner, Michael; Dumontet, Charles; Umana, Pablo; Niederfellner, Gerhard; Bacac, Marina; Klein, Christian

    2013-10-01

    We report the first preclinical in vitro and in vivo comparison of GA101 (obinutuzumab), a novel glycoengineered type II CD20 monoclonal antibody, with rituximab and ofatumumab, the two currently approved type I CD20 antibodies. The three antibodies were compared in assays measuring direct cell death (AnnexinV/PI staining and time-lapse microscopy), complement-dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cell-mediated phagocytosis (ADCP), and internalization. The models used for the comparison of their activity in vivo were SU-DHL4 and RL xenografts. GA101 was found to be superior to rituximab and ofatumumab in the induction of direct cell death (independent of mechanical manipulation required for cell aggregate disruption formed by antibody treatment), whereas it was 10 to 1,000 times less potent in mediating CDC. GA101 showed superior activity to rituximab and ofatumumab in ADCC and whole-blood B-cell depletion assays, and was comparable with these two in ADCP. GA101 also showed slower internalization rate upon binding to CD20 than rituximab and ofatumumab. In vivo, GA101 induced a strong antitumor effect, including complete tumor remission in the SU-DHL4 model and overall superior efficacy compared with both rituximab and ofatumumab. When rituximab-pretreated animals were used, second-line treatment with GA101 was still able to control tumor progression, whereas tumors escaped rituximab treatment. Taken together, the preclinical data show that the glyoengineered type II CD20 antibody GA101 is differentiated from the two approved type I CD20 antibodies rituximab and ofatumumab by its overall preclinical activity, further supporting its clinical investigation. ©2013 AACR.

  19. Does Autoimmunity have a Role in Myoclonic Astatic Epilepsy? A Case Report of Voltage Gated Potassium Channel Mediated Seizures.

    Science.gov (United States)

    Sirsi, Deepa; Dolce, Alison; Greenberg, Benjamin M; Thodeson, Drew

    2016-01-01

    There is expanding knowledge about the phenotypic variability of patients with voltage gated potassium channel complex (VGKC) antibody mediated neurologic disorders. The phenotypes are diverse and involve disorders of the central and peripheral nervous systems. The central nervous system manifestations described in the literature include limbic encephalitis, status epilepticus, and acute encephalitis. We report a 4.5 year-old boy who presented with intractable Myoclonic Astatic Epilepsy (MAE) or Doose syndrome and positive VGKC antibodies in serum. Treatment with steroids led to resolution of seizures and electrographic normalization. This case widens the spectrum of etiologies for MAE to include autoimmunity, in particular VGKC auto-antibodies and CNS inflammation, as a primary or contributing factor. There is an evolving understanding of voltage gated potassium channel complex mediated autoimmunity in children and the role of inflammation and autoimmunity in MAE and other intractable pediatric epilepsy syndromes remains to be fully defined. A high index of suspicion is required for diagnosis and appropriate management of antibody mediated epilepsy syndromes.

  20. Improved affinity of a chicken single-chain antibody to avian ...

    African Journals Online (AJOL)

    linyuan

    2011-12-12

    Dec 12, 2011 ... Jianhua Wang. 1. , Ying Zhang ... et al., 1991; Dougan et al., 1998; Chang et al., 2009). The site-directed ... Analysis of the three-dimensional structure of the antigen-antibody ..... Altering the fine specificity of an anti-Legionella ...

  1. Smoking and subsequent human papillomavirus infection: a mediation analysis.

    Science.gov (United States)

    Eldridge, Ronald C; Pawlita, Michael; Wilson, Lauren; Castle, Philip E; Waterboer, Tim; Gravitt, Patti E; Schiffman, Mark; Wentzensen, Nicolas

    2017-11-01

    Smoking is an established risk factor for a human papillomavirus (HPV) infection advancing to cervical precancer and cancer, but its role earlier in the natural history is less clear. Smoking is inversely associated with possessing HPV antibodies from a past infection suggesting that smoking may influence acquiring subsequent infections. In a cohort of 1976 U.S. women, we evaluate whether reduced antibodies to HPV-16 is a mechanism for smoking's role on acquiring a subsequent HPV-16 infection, through the analytic technique of causal mediation analysis. We posit a causal model and estimate two counterfactually defined effects: a smoking impaired antibody-mediated indirect effect and a nonmediated direct effect representing all other potential mechanisms of smoking. Compared to never smokers, current smokers had increased odds of HPV-16 infection by the antibody-mediated indirect effect (odds ratio [OR] = 1.29; 95% confidence interval [CI]: 1.11, 1.73); the estimated direct effect was very imprecise (OR = 0.57; 95% CI, 0.26-1.13). We observed a stronger estimated indirect effect among women who smoked at least half a pack of cigarettes daily (OR = 1.61, 95% CI, 1.27-2.15) than among women who smoked less than that threshold (OR = 1.09; 95% CI, 0.94-1.44). This is the first study to directly test the mechanism underlying smoking as an HPV cofactor. The results support current smoking as a risk factor earlier in the natural history of HPV and are consistent with the hypothesis that smoking increases the risk of a subsequent infection by reducing immunity. Published by Elsevier Inc.

  2. Family poverty is associated with cytomegalovirus antibody titers in U.S. children.

    Science.gov (United States)

    Dowd, Jennifer B; Palermo, Tia M; Aiello, Allison E

    2012-01-01

    Early life environmental and psychological influences are thought to play an important role in the development of the immune system. Antibody response to latent herpesviruses has been used as an indirect measure of cell-mediated immune function but has seldom been applied to younger age groups. We used data from the 1999-2004 National Health and Nutrition Examination Survey (NHANES) to test for an association between family poverty and continuous antibody response to cytomegalovirus in U.S. children aged 6-16 (N = 2,226) using ordinary least squares regression. Poverty was significantly associated with increased antibody levels among seropositive individuals. The association between income and antibody levels exhibited a threshold effect, with additional income beyond the poverty line not associated with increased antibody titers. This relationship was more robust among older compared with younger children. Early life social factors such as family poverty could have detrimental impacts on the developing immune system, with potentially important consequences for later life health outcomes. Exposure to socioeconomic stressors for longer periods during childhood may further enhance alterations in immune response to cytomegalovirus.

  3. Antithyroglobulin Antibodies and Antimicrosomal Antibodies in Various Thyroid Diseases

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Gwon Jun; Hong, Key Sak; Choi, Kang Won; Lee, Kyu; Koh, Chang Soon; Lee, Mun Ho; Park, Sung Hoe; Chi, Je Geun; Lee, Sang Kook [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1979-03-15

    The authors investigated the incidence of antithyroglobulin antibodies and antibodies and antimicrosomal antibodies measured by tanned red cell hemagglutination method in subjects suffering from various thyroid disorders. 1) In 15 normal patients, neither suffering from any thyroid diseases nor from any other autoimmune disorders, the antithyroglobulin antibodies were all negative, but the antimicrosomal antibody was positive only in one patient (6.7%). 2) The antithyroglobulin antibodies were positive in 31.5% (34 patients) of 108 patients with various thyroid diseases, and the antimicrosomal antibodies were positive in 37.0% (40 patients). 3) of the 25 patients with Graves' diseases, 7 patients (28.0%) showed positive for the antithyroglobulin antibodies, and 9 (36.0%) for the antimicrosomal antibodies. There was no definite differences in clinical and thyroid functions between the groups with positive and negative results. 4) Both antibodies were positive in 16 (88.9%) and 17 (94.4%) patients respectively among 18 patients with Hashimoto's thyroiditis, all of them were diagnosed histologically. 5) Three out of 33 patients with thyroid adenoma showed positive antibodies, and 3 of 16 patients with thyroid carcinoma revealed positive antibodies. 6) TRCH antibodies demonstrated negative results in 2 patients with subacute thyroiditis, but positive in one patient with idiopathic primary myxedema. 7) The number of patients with high titers(>l:802) was 16 for antithyroglobulin antibody, and 62.5% (10 patients) of which was Hashimoto's thyroiditis. Thirteen (65.0) of 20 patients with high titers (>l:802) for antimicrosomal antibody was Hashimoto's thyroiditis. TRCH test is a simple, sensitive method, and has high reliability and reproducibility. The incidences and titers of antithyroglobulin antibody and antimicrosomal antibody are especially high in Hashimoto's thyroiditis.

  4. Improved detection of Pneumocystis carinii by an immunofluorescence technique using monoclonal antibodies

    DEFF Research Database (Denmark)

    Orholm, M; Holten-Andersen, W; Lundgren, Jens Dilling

    1990-01-01

    To assess whether a recently developed indirect immunofluorescent stain using monoclonal antibodies was more sensitive in detecting Pneumocystis carinii than the combination of Giemsa and methenamine silver nitrate stains which has routinely been used in the laboratory, 88 lavage fluid specimens...... silver nitrate and toluidine blue O. Immunofluorescence using the monoclonal antibodies from the NIH was significantly more sensitive than any other single staining method and than the combination of Giemsa and methenamine silver nitrate staining. The study also showed that the cytospin centrifuge...

  5. Etiology and pathogenesis of antisperm antibody

    Directory of Open Access Journals (Sweden)

    farhad Shahsavar

    2011-06-01

    Full Text Available Antisperm antibodies (ASA occur in men and women and may significantly impair fertility. In this case, the testis is an immunologically privileged site where germ cell antigens are protected from autoimmune attack. However, due to disruption of the blood-testis barrier occurring from testicular injury, or as a consequence of trauma to the epididymis or vas deferens many testicular proteins get autoantigenic during immunological challenges resulting in the formation of ASA in the blood serum, seminal plasma or located on the sperm membrane. ASA have also been reported to be associated with inflammation, cryptorchidism, varicocele and surgical intervention in the genital organs. ASA may interfere with different sperm functions, which are essential for the fertilization process.This review article will help to increase our understanding of the specific mechanisms that elicit the autoimmune response to sperm and of the pathogenesis of ASA that leads to an antibody-mediated infertility.

  6. Anti-Amyloid-?-Mediated Positron Emission Tomography Imaging in Alzheimer's Disease Mouse Brains

    OpenAIRE

    McLean, Daniel; Cooke, Michael J.; Wang, Yuanfei; Green, David; Fraser, Paul E.; George-Hyslop, Peter St; Shoichet, Molly S.

    2012-01-01

    Antibody-mediated imaging of amyloid β (Aβ) in Alzheimer's disease (AD) offers a promising strategy to detect and monitor specific Aβ species, such as oligomers, that have important pathological and therapeutic relevance. The major current limitation of antibodies as a diagnostic and imaging device is poor blood-brain-barrier permeability. A classical anti-Aβ antibody, 6E10, is modified with 10 kDa polyethylene glycol (PEG) and a positron emitting isotope, Copper-64 (t(½) = 12.7 h), and intra...

  7. Naturally acquired antibodies target the glutamate-rich protein on intact merozoites and predict protection against febrile malaria

    DEFF Research Database (Denmark)

    Kana, Ikhlaq Hussain; Adu, Bright; Tiendrebeogo, Régis Wendpayangde

    2017-01-01

    febrile malaria. Similarly, GLURP-specific antibodies previously shown to be protective against febrile malaria in this same cohort were significantly associated with OP activity in this study. GLURP-specific antibodies recognized merozoites and also mediated OP activity. Conclusions.: These findings......Background.: Plasmodium species antigens accessible at the time of merozoite release are likely targets of biologically functional antibodies. Methods.: Immunoglobulin G (IgG) antibodies against intact merozoites were quantified in the plasma of Ghanaian children from a longitudinal cohort using...... a novel flow cytometry-based immunofluorescence assay. Functionality of these antibodies, as well as glutamate-rich protein (GLURP)-specific affinity-purified IgG from malaria hyperimmune Liberian adults, was assessed by the opsonic phagocytosis (OP) assay. Results.: Opsonic phagocytosis activity...

  8. The role of social media use in improving cancer survivors' emotional well-being: a moderated mediation study.

    Science.gov (United States)

    Jiang, Shaohai

    2017-06-01

    In the USA, levels of emotional well-being among cancer survivors remain low. Social media is recognized as important to improve their emotional well-being. However, little is known about social mechanisms that underlie the impact of health-related social media in cancer care. This study proposed a moderated mediation model to signify a pathway linking social media use to emotional well-being. Four-hundred and fifty-nine cancer survivors identified through the 2013 US-based Health Information National Trends Survey were included for data analysis. First, structural equation modeling was conducted to examine the path from social media use to emotional well-being, mediated by patient activation. Second, hierarchical regression was performed to test the moderation effect of emotion management. Last, a normal theory-based approach was used to explore the final moderated mediation model. The effect of health-related social media use on emotional well-being was completely mediated by patient activation. Also, emotion management positively moderated the effect of patient activation on emotional well-being. Last, emotion management positively moderated the mediation pathway from health-related social media use to patient activation, and finally, to emotional well-being. Health-related social media, by itself, is not sufficient to bring about improvement in cancer survivors' emotional well-being. Patient activation and emotion management play a significant role. In future interventions designed to improve cancer survivors' emotional health, health practitioners should not only encourage cancer survivors to use social media for health purposes, but also activate them in the course of care, and improve their emotion self-management skills.

  9. Time to symptom improvement using elimination diets in non-IgE-mediated gastrointestinal food allergies.

    Science.gov (United States)

    Lozinsky, Adriana Chebar; Meyer, Rosan; De Koker, Claire; Dziubak, Robert; Godwin, Heather; Reeve, Kate; Dominguez Ortega, Gloria; Shah, Neil

    2015-08-01

    The prevalence of food allergy has increased in recent decades, and there is paucity of data on time to symptom improvement using elimination diets in non-Immunoglobulin E (IgE)-mediated food allergies. We therefore aimed to assess the time required to improvement of symptoms using a symptom questionnaire for children with non-IgE-mediated food allergies on an elimination diet. A prospective observational study was performed on patients with non-IgE-mediated gastrointestinal food allergies on an elimination diet, who completed a questionnaire that includes nine evidence-based food allergic symptoms before and after the exclusion diet. The questionnaire measured symptoms individually from 0 (no symptom) to 5 (most severe) and collectively from 0 to 45. Children were only enrolled in the study if collectively symptoms improved with the dietary elimination within 4 or 8 weeks. Data from 131 patients were analysed including 90 boys with a median age of 21 months [IQR: 7 to 66]. Based on the symptom questionnaire, 129 patients (98.4%) improved after 4-week elimination diet and only two patients improved after 8 weeks. A statistically significant difference before and after commencing the elimination diet was seen in all nine recorded symptoms (all p < 0.001), and in the median of overall score (p < 0.001). This is the first study attempting to establish time to improve after commencing the diet elimination. Almost all children in this study improved within 4 weeks of following the elimination diet, under dietary supervision. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Monoclonal antibody-based immunoassays.

    Science.gov (United States)

    Appleby, P; Reischl, U

    1998-01-01

    An immunoassay may be defined as an assay that employs an immunological reagent, usually an antibody, to confer specificity for the ligand being measured. As a corollary to this, the discovery, and subsequent development, of monoclonal antibodies (MAbs) has greatly expanded the application and use of immunoassays. Polyclonal reagents, with their associated problems of specificity and quality control, have now been largely replaced by readily available MAbs of potential immortality and well-defined specificity and affinity. This has resulted, in the last two decades, in a great expansion in the range of immunoassays available and also a significant improvement in their reproducibility and reliability.

  11. Identification of anti-HPA-1a allo-antibodies using IgG platelet antibody detection and crossmatch system assay with Galileo Echo.

    Science.gov (United States)

    Di Cristofaro, Julie; Frassati, Coralie; Montagnie, Rolande; Basire, Agnes; Merieux, Yves; Picard, Christophe

    2015-01-01

    Fetal/neonatal allo-immune thrombocytopenia is the most frequent and the most dangerous clinical condition involving anti-human platelet antigens (HPA)-1a allo-antibodies. Anti-HPA-1a allo-immunization requires rapid and accurate diagnosis to determine appropriate treatment. The Capture-P Ready-Screen assay (C-PRS) is a new qualitative immunoassay to detect IgG anti-human leukocyte antigen (HLA) and anti-HPA allo-antibodies. The aim of this study is to assess the identification of anti-HPA-1a allo-antibodies using the C-PRS assay, associated with HLA class I stripping reagents, on the automated benchtop analyzer Galileo Echo. Forty-nine sera were analyzed: without anti-HLA class I or anti-HPA allo-antibodies, with anti-HLA class I allo-antibodies, with anti-HPA-1a allo-antibodies, among which with anti-HLA class I allo-antibodies. None of the samples without allo-antibodies were reactive. Only anti-HLA antibodies, detected by cytotoxicity-dependent complement and not by Luminex, remained positive before and after stripping reagents. Of the 13 samples, anti-HPA-1a allo-antibodies that were correctly identified before and after incubation with HLA assassin reagent were 70% and 85%, respectively. Anti-glycoprotein auto-antibodies and anti-HLA allo-antibodies do not interfere with the detection of anti-HPA-1a antibodies. This preliminary study indicates that further improvement of the test will be helpful in developing a clinically useful assay in the future.

  12. The effect of timing and graft dysfunction on survival and cardiac allograft vasculopathy in antibody-mediated rejection.

    Science.gov (United States)

    Clerkin, Kevin J; Restaino, Susan W; Zorn, Emmanuel; Vasilescu, Elena R; Marboe, Charles C; Mancini, Donna M

    2016-09-01

    Antibody-mediated rejection (AMR) has been associated with increased death and cardiac allograft vasculopathy (CAV). Early studies suggested that late AMR was rarely associated with graft dysfunction, whereas recent reports have demonstrated an association with increased mortality. We investigated the timing of AMR and its association with graft dysfunction, death, and CAV. This retrospective cohort study identified all adult orthotopic heart transplant (OHT) recipients (N = 689) at Columbia University Medical Center from 2004 to 2013. There were 68 primary cases of AMR, which were stratified by early ( 1 year post-OHT) AMR. Kaplan-Meier survival analysis and modeling was performed with multivariable logistic regression and Cox proportional hazards regression. From January 1, 2004, through October 1, 2015, early AMR (median 23 days post-OHT) occurred in 43 patients and late AMR (median 1,084 days post-OHT) occurred in 25. Graft dysfunction was less common with early compared with late AMR (25.6% vs 56%, p = 0.01). Patients with late AMR had decreased post-AMR survival compared with early AMR (1 year: 80% vs 93%, 5 years: 51% vs 73%, p < 0.05). When stratified by graft dysfunction, only those with late AMR and graft dysfunction had worse survival (30 days: 79%, 1 year: 64%, 5 years: 36%; p < 0.006). The association remained irrespective of age, sex, donor-specific antibodies, left ventricular assist device use, reason for OHT, and recovery of graft function. Similarly, those with late AMR and graft dysfunction had accelerated development of de novo CAV (50% at 1 year; hazard ratio, 5.42; p = 0.009), whereas all other groups were all similar to the general transplant population. Late AMR is frequently associated with graft dysfunction. When graft dysfunction is present in late AMR, there is an early and sustained increased risk of death and rapid development of de novo CAV despite aggressive treatment. Copyright © 2016 International Society for Heart and Lung

  13. The value of LGI1, Caspr2 and voltage-gated potassium channel antibodies in encephalitis.

    Science.gov (United States)

    van Sonderen, Agnes; Petit-Pedrol, Mar; Dalmau, Josep; Titulaer, Maarten J

    2017-05-01

    The discovery, in 2010, of autoantibodies against the extracellular proteins LGI1 and Caspr2 facilitated a change of view regarding the clinical importance of voltage-gated potassium channel (VGKC) antibodies. Currently, these antibodies are all classified as VGKC-complex antibodies, and are commonly considered to have a similar clinical value. However, studies from the past few years show that the immune responses mediated by these antibodies have differing clinical relevance. Here, we review the clinical importance of these immune responses in three settings: patients with anti-LGI1 antibodies, patients with anti-Caspr2 antibodies, and patients with antibodies against the VGKC complex that lack LGI1 and Caspr2 specificity. Antibodies against LGI1 and Caspr2 are associated with different but well-defined syndromes, whereas the clinical importance of VGKC-complex antibodies without LGI1 and Caspr2 specificity is questionable. We describe each of these syndromes, discuss the function of the target antigens and review the limited paediatric literature on the topic. The findings emphasize the importance of defining these disorders according to the molecular identity of the targets (LGI1 or Caspr2), and caution against the use of VGKC-complex antibodies for the diagnosis and treatment of patients without further definition of the antigen.

  14. Induction of human immunodeficiency virus neutralizing antibodies using fusion complexes.

    Science.gov (United States)

    Zipeto, Donato; Matucci, Andrea; Ripamonti, Chiara; Scarlatti, Gabriella; Rossolillo, Paola; Turci, Marco; Sartoris, Silvia; Tridente, Giuseppe; Bertazzoni, Umberto

    2006-05-01

    Human immunodeficiency virus-1 (HIV-1) infects cells by membrane fusion that is mediated by the envelope proteins gp120/gp41 and the cellular receptors CD4 and CCR5. During this process, some conserved viral epitopes are temporarily exposed and may induce a neutralizing antibody response when fixed in the fusogenic conformation. These transient structures are conserved and may be effective antigens for use in an anti-HIV-1 vaccine. In this study we tested different conditions of preparation of fusion complexes inducing neutralizing antibodies against both R5 and X4 tropic HIV-1 strains. Cell lines expressing HIV-1 gp120/gp41 and CD4-CCR5 were prepared and conditions for producing fusion complexes were tested. Complexes produced at different temperature and fixative combinations were used to immunize mice. Results indicated that (a) fusion complexes prepared at either 21 degrees C, 30 degrees C or 37 degrees C were immunogenic and induced neutralizing antibodies against both R5 and X4 HIV-1 heterologous isolates; (b) after extensive purification of antibodies there was no cytotoxic effect; (c) complexes prepared at 37 degrees C were more immunogenic and induced higher titers of neutralizing antibodies than complexes prepared at either 21 degrees C or 30 degrees C; (d) the fixative used did not affect the titer of neutralizing antibodies except for glutaraldehyde which was ineffective; (e) the neutralizing activity was retained after CD4-CCR5 antibody removal. The production of higher titers of neutralizing antibody with fusion complexes prepared at 37 degrees C, as compared to lower temperatures, may be related to the induction of antibodies against many different conformation intermediates that subsequently act synergistically at different steps in the fusion process.

  15. Potential of the Antibody Against cis-Phosphorylated Tau in the Early Diagnosis, Treatment, and Prevention of Alzheimer Disease and Brain Injury.

    Science.gov (United States)

    Lu, Kun Ping; Kondo, Asami; Albayram, Onder; Herbert, Megan K; Liu, Hekun; Zhou, Xiao Zhen

    2016-11-01

    Alzheimer disease (AD) and chronic traumatic encephalopathy (CTE) share a common neuropathologic signature-neurofibrillary tangles made of phosphorylated tau-but do not have the same pathogenesis or symptoms. Although whether traumatic brain injury (TBI) could cause AD has not been established, CTE is shown to be associated with TBI. Until recently, whether and how TBI leads to tau-mediated neurodegeneration was unknown. The unique prolyl isomerase Pin1 protects against the development of tau-mediated neurodegeneration in AD by converting the phosphorylated Thr231-Pro motif in tau (ptau) from the pathogenic cis conformation to the physiologic trans conformation, thereby restoring ptau function. The recent development of antibodies able to distinguish and eliminate both conformations specifically has led to the discovery of cis-ptau as a precursor of tau-induced pathologic change and an early driver of neurodegeneration that directly links TBI to CTE and possibly to AD. Within hours of TBI in mice or neuronal stress in vitro, neurons prominently produce cis-ptau, which causes and spreads cis-ptau pathologic changes, termed cistauosis. Cistauosis eventually leads to widespread tau-mediated neurodegeneration and brain atrophy. Cistauosis is effectively blocked by the cis-ptau antibody, which targets intracellular cis-ptau for proteasome-mediated degradation and prevents extracellular cis-ptau from spreading to other neurons. Treating TBI mice with cis-ptau antibody not only blocks early cistauosis but also prevents development and spreading of tau-mediated neurodegeneration and brain atrophy and restores brain histopathologic features and functional outcomes. Thus, cistauosis is a common early disease mechanism for AD, TBI, and CTE, and cis-ptau and its antibody may be useful for early diagnosis, treatment, and prevention of these devastating diseases.

  16. Identifying the Conditions Under Which Antibodies Protect Against Infection by Equine Infectious Anemia Virus

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    Elissa J. Schwartz

    2014-05-01

    Full Text Available The ability to predict the conditions under which antibodies protect against viral infection would transform our approach to vaccine development. A more complete understanding is needed of antibody protection against lentivirus infection, as well as the role of mutation in resistance to an antibody vaccine. Recently, an example of antibody-mediated vaccine protection has been shown via passive transfer of neutralizing antibodies before equine infectious anemia virus (EIAV infection of horses with severe combined immunodeficiency (SCID. Viral dynamic modeling of antibody protection from EIAV infection in SCID horses may lead to insights into the mechanisms of control of infection by antibody vaccination. In this work, such a model is constructed in conjunction with data from EIAV infection of SCID horses to gain insights into multiple strain competition in the presence of antibody control. Conditions are determined under which wild-type infection is eradicated with the antibody vaccine. In addition, a three-strain competition model is considered in which a second mutant strain may coexist with the first mutant strain. The conditions that permit viral escape by the mutant strains are determined, as are the effects of variation in the model parameters. This work extends the current understanding of competition and antibody control in lentiviral infection, which may provide insights into the development of vaccines that stimulate the immune system to control infection effectively.

  17. Upregulation of HLA Class I Expression on Tumor Cells by the Anti-EGFR Antibody Nimotuzumab

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    Greta Garrido

    2017-10-01

    Full Text Available Defining how epidermal growth factor receptor (EGFR-targeting therapies influence the immune response is essential to increase their clinical efficacy. A growing emphasis is being placed on immune regulator genes that govern tumor – T cell interactions. Previous studies showed an increase in HLA class I cell surface expression in tumor cell lines treated with anti-EGFR agents. In particular, earlier studies of the anti-EGFR blocking antibody cetuximab, have suggested that increased tumor expression of HLA class I is associated with positive clinical response. We investigated the effect of another commercially available anti-EGFR antibody nimotuzumab on HLA class I expression in tumor cell lines. We observed, for the first time, that nimotuzumab increases HLA class I expression and its effect is associated with a coordinated increase in mRNA levels of the principal antigen processing and presentation components. Moreover, using 7A7 (a specific surrogate antibody against murine EGFR, we obtained results suggesting the importance of the increased MHC-I expression induced by EGFR-targeted therapies display higher in antitumor immune response. 7A7 therapy induced upregulation of tumor MHC-I expression in vivo and tumors treated with this antibody display higher susceptibility to CD8+ T cells-mediated lysis. Our results represent the first evidence suggesting the importance of the adaptive immunity in nimotuzumab-mediated antitumor activity. More experiments should be conducted in order to elucidate the relevance of this mechanism in cancer patients. This novel immune-related antitumor mechanism mediated by nimotuzumab opens new perspectives for its combination with various immunotherapeutic agents and cancer vaccines.

  18. A multi-subunit Chlamydia vaccine inducing neutralizing antibodies and strong IFN-γ(+) CMI responses protects against a genital infection in minipigs

    DEFF Research Database (Denmark)

    Bøje, Sarah; Olsen, Anja Weinreich; Erneholm, Karin

    2016-01-01

    Chlamydia is the most widespread sexually transmitted bacterial disease and a prophylactic vaccine is highly needed. Ideally, this vaccine is required to induce a combined response of Th1 cell-mediated immune (CMI) response in concert with neutralizing antibodies. Using a novel Göttingen minipig...... animal model, we evaluated the immunogenicity and efficacy of a multi-subunit vaccine formulated in the strong Th1-inducing adjuvant CAF01. We evaluated a mixture of two fusion proteins (Hirep1 and CTH93) designed to promote either neutralizing antibodies or cell-mediated immunity, respectively. Hirep1...

  19. Antibody specific epitope prediction-emergence of a new paradigm.

    Science.gov (United States)

    Sela-Culang, Inbal; Ofran, Yanay; Peters, Bjoern

    2015-04-01

    The development of accurate tools for predicting B-cell epitopes is important but difficult. Traditional methods have examined which regions in an antigen are likely binding sites of an antibody. However, it is becoming increasingly clear that most antigen surface residues will be able to bind one or more of the myriad of possible antibodies. In recent years, new approaches have emerged for predicting an epitope for a specific antibody, utilizing information encoded in antibody sequence or structure. Applying such antibody-specific predictions to groups of antibodies in combination with easily obtainable experimental data improves the performance of epitope predictions. We expect that further advances of such tools will be possible with the integration of immunoglobulin repertoire sequencing data. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Exploration of novel strategies to enhance monoclonal antibodies targeting

    International Nuclear Information System (INIS)

    Khawli, L.A.; Epstein, A.L.

    1997-01-01

    This paper highlights the major obstacles and prospects of antibody targeting for the radio imaging and therapy of human malignant lymphomas and more challenging solid tumors. To improve the therapeutic potential of monoclonal antibodies, the authors have focused their attention on the development of new and successful methods to augment antibody uptake in the tumor. These approaches include the use of radiolabeled streptavidin to target biotinylated monoclonal antibodies already bound to tumor, pretreatment with vasoactive immunoconjugates, and the use of chemically modified antibodies. Because of the promising preclinical data obtained with these three newer approaches, plans are underway to test them in the clinic. More generally, these approaches are applicable to the use of other monoclonal antibody/tumor systems for the diagnosis and therapy of human cancers and related diseases

  1. Monoclonal antibody hapten radiopharmaceutical delivery

    International Nuclear Information System (INIS)

    Goodwin, D.A.; McTigue, M.

    1986-01-01

    One hundred μg of monoclonal antibody (MoAb) CHA255 with a binding constant Kb of 4 x 10 9 was complexed with indium-111 labelled BLEDTA II, BLEDTA IV, benzyl EDTA, and an EDTA conjugate of Fab. The 24-h tumour and organ distribution of BALB/c mice bearing KHJJ tumours was studied for each compound alone, the antibody complex, and 3 h following a chelate chase of the antibody complex. Whole body biological half-life was measured for 7 days with and without a chelate chase for each antibody complex. The 24-h whole body counts dropped 20 to 60% and blood concentration fell over 89% within 3 h of administering the chelate chase. Theoretical equivalent human organ doses were calculated from the 24-h organ concentrations, effective half-life, and MIRD 11 S values (absorbed dose per cumulated activity). Liver and spleen were the target organs, with the dose ranging from 0.50 to 3.91 rads mCi -1 . The reduction in organ radiation dose varied up to 95% following the chelate chase. Rapid selective renal clearance of chelate labelled radiopharmaceuticals by competitive inhibition (chelate chase) of their reversible binding to monoclonal antibodies enhances tumour imaging and improves the radiation dosimetry. (author)

  2. Characterization of the mechanism of protection mediated by CS-D7, a monoclonal antibody to Staphylococcus aureus iron regulated surface determinant B (IsdB

    Directory of Open Access Journals (Sweden)

    Gregory ePancari

    2012-03-01

    Full Text Available We previously reported the development of a human monoclonal antibody (CS-D7, IgG1 with specificity and affinity for the iron regulated surface determinant B (IsdB of Staphylococcus aureus. CS-D7 mediates opsonophagocytic killing in vitro and protection in a murine sepsis model. In light of recent data indicating that IsdB specific T cells (CD4+, Th17, not Ab, mediate protection after vaccination with IsdB, it is important to investigate the mechanism of protection mediated by CS-D7. The mAb was examined to determine if it blocked heme binding to IsdB in vitro. The mAb was not found to have heme blocking activity, nor did it prevent bacterial growth under in vivo conditions, in an implanted growth chamber. To assess the role of the mAb Fc a point mutation was introduced at aa 297 (CS-D7●N297A. This point mutation removes Fc effector functions. In vitro analysis of the mutein confirmed that it lacked measurable binding to FcγR, and that it did not fix complement. The mutein had dramatically reduced in vitro opsonic OP activity compared to CS-D7. Nonetheless, the mutein conferred protection equivalent to the wild type mAb in the murine sepsis model. Both wild type and mutein mAbs were efficacious in FcγR deletion mice (including both FcγRII-/- mice and FcγRIII-/- mice, indicating that these receptors were not essential for mAb mediated protection in vivo. Protection mediated by CS-D7 was lost in Balb/c mice depleted of C3 with cobra venom factor (CFV, was lost in mice depleted of superoxide dismutase (SOD in P47phox deletion mice, and was absent in SCID mice. Enhanced clearance of S. aureus in the liver of CS-D7 treated mice and enhanced production of INF-γ, but not of IL17, may play a role in the mechanism of protection mediated by the mAb. CS-D7 apparently mediates survival in challenged mice through a mechanism involving complement, phagocytes, and lymphocytes, but which does not depend on interaction with FcγR, or on blocking heme

  3. Isolation of a human anti-epidermal growth factor receptor Fab antibody, EG-19-11, with subnanomolar affinity from naïve immunoglobulin repertoires using a hierarchical antibody library system.

    Science.gov (United States)

    Hur, Byung-ung; Yoon, Jae-bong; Liu, Li-Kun; Cha, Sang-hoon

    2010-11-30

    Specific antibodies that possess a subnanomolar affinity are very difficult to obtain from human naïve immunoglobulin repertoires without the use of lengthy affinity optimization procedures. Here, we designed a hierarchical phage-displayed antibody library system to generate an enormous diversity of combinatorial Fab fragments (6×10(17)) and attempted to isolate high-affinity Fabs against the human epidermal growth factor receptor (EGFR). A primary antibody library, designated HuDVFab-8L, comprising 4.5×10(9) human naïve heavy chains and eight unspecified human naïve light chains was selected against the EGFR-Fc protein by biopanning, and four anti-EGFR Fab clones were isolated. Because one of the Fab clones, denoted EG-L2-11, recognized a native EGFR expressed on A431 cells, the heavy chain of the Fab was shuffled with a human naïve light chain repertoire with a diversity of 1.4×10(8) and selected a second time against the EGFR-Fc protein again. One EG-L2-11 variant, denoted EG-19-11, recognized an EGFR epitope that was almost the same as that bound by cetuximab and had a K(D) of approximately 540 pM for soluble EGFR, which is about 7-fold higher than that of the FabC225 derived from cetuximab. This variant was also internalized by A431 cells, likely via receptor-mediated endocytosis, and it efficiently inhibited EGF-mediated tyrosine phosphorylation of the EGFR. These results demonstrate that the use of our hierarchical antibody library system is advantageous in generating fully human antibodies especially with a therapeutic purpose. Copyright © 2010 Elsevier B.V. All rights reserved.

  4. Use of AN Eosinophil Specific Monoclonal Antibody in Assessing Eosinophil Function.

    Science.gov (United States)

    Minkoff, Marjorie Sue

    A monoclonal antibody to an eosinophil specific determinant is very important in assessing eosinophil function during helminthic infection. Eosinophils induced by Schistosoma mansoni infection in BALB/c mice were used to induce C57B1/6 immunocytes for production of hybridomas secreting eosinophil monoclonal antibodies. These antibodies were shown to react with an eosinophil surface epitope but not with neutrophils or macrophages as determined by ELISA, immunodiffusion, immunofluorescence, and immunoblot assay. Affinity chromatography with eosinophil chemotactic factor-sepharose consistently selected out a { rm M_ R} 67,000 protein from solubilized eosinophil membrane antigens but not from neutrophil and macrophage antigens. In vitro studies showed that the eosinophil-specific monoclonal antibodies abrogated antibody-dependent eosinophil -mediated killing of S. mansoni schistosomula using mouse, rat or human eosinophils. Neutrophil and macrophage killing activities were unaffected. The monoclonal antibodies effected complement-dependent lysis of mouse and rat eosinophils but not of human eosinophils. ECF-treated eosinophils showed enhanced killing of schistosomula which was blocked by the monoclonal antibody. Murine and human eosinophils preincubated with monoclonal antibody exhibited decreased chemotaxis to ECF at optimal chemotactic concentrations. The monoclonal antibody also blocked eosinophil binding to ECF- sepharose beads. In vivo induction of peripheral blood eosinophilia by injection of S. mansoni eggs was suppressed by injections of monoclonal antibodies 2CD13 and 2QD45 in mouse and rat experimental models. Eosinophilia induced by keyhole limpet hemocyanin- cyclophosphamide treatment was also suppressed by monoclonal antibody in both murine and rat systems. Pulmonary granulomas in mice given egg injection and monoclonal antibody were smaller and contained fewer eosinophils than those granulomas from mice given eggs only. In immuno-biochemical studies, the

  5. Antibody-Conjugated Nanoparticles for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Manuel Arruebo

    2009-01-01

    Full Text Available Nanoscience and Nanotechnology have found their way into the fields of Biotechnology and Medicine. Nanoparticles by themselves offer specific physicochemical properties that they do not exhibit in bulk form, where materials show constant physical properties regardless of size. Antibodies are nanosize biological products that are part of the specific immune system. In addition to their own properties as pathogens or toxin neutralizers, as well as in the recruitment of immune elements (complement, improving phagocytosis, cytotoxicity antibody dependent by natural killer cells, etc., they could carry several elements (toxins, drugs, fluorochroms, or even nanoparticles, etc. and be used in several diagnostic procedures, or even in therapy to destroy a specific target. The conjugation of antibodies to nanoparticles can generate a product that combines the properties of both. For example, they can combine the small size of nanoparticles and their special thermal, imaging, drug carrier, or magnetic characteristics with the abilities of antibodies, such as specific and selective recognition. The hybrid product will show versatility and specificity. In this review, we analyse both antibodies and nanoparticles, focusing especially on the recent developments for antibody-conjugated nanoparticles, offering the researcher an overview of the different applications and possibilities of these hybrid carriers.

  6. Preparation of TiO{sub 2} nanosheet-carbon nanotube composite as immobilization platform for both primary and secondary antibodies in electrochemical immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaoqiang, E-mail: 13781157777@163.com; Liu, Pepipei; Huo, Xiaohe; Liu, Xiuhua; Liu, Jin

    2016-11-23

    TiO{sub 2} nanosheets (TNSs) were synthesized and deposited on multi-wall carbon nanotubes (MWCNTs) to form a nano-composite through a hydrothermal method, followed by the characterization with various spectroscopic and microscopic techniques. The TNS-MWCNT composite was then applied as not only an electrode scaffold to immobilize primary antibody, but also as a carrier to load secondary antibody and horseradish peroxidase (HRP). In both cases, bis(sulfosuccinimidyl) suberate sodium salt acted as an amino cross-linker to covalently bind the biomolecules on TNS-MWCNT composite through their surface primary amino groups. After the sandwich-type immunoreaction, HPR was quantitatively captured on the electrode surface via the binding between secondary antibody and antigen, and electrochemical response of the immunosensor was then amplified by a H{sub 2}O{sub 2} mediated HRP catalytic reaction. Using α-Fetoprotein as a model analyte, a linear range between 0.005 and 320 ng mL{sup −1} with a detection limit of 2.0 pg mL{sup −1} was achieved by differential pulse voltammetry. The improved immunosensor performance could be attributed to the biocompatibility and high specific surface area of TNS, and excellent electrical conductivity of MWCNTs, which accelerated the electron transfer at the electrode surface. - Highlights: • TiO{sub 2} nanosheet-carbon nanotube composite was synthesized by hydrothermal method. • The composite exhibits improved properties compared to the individuals. • The composite is designed as electrode scaffold for immobilizing primary antibody. • Secondary antibody and horseradish peroxidase are immobilized on the composite as a label. • The tracing label exhibits great amplification effect for immunosensing.

  7. Peer Mediated Theatrical Engagement for Improving Reciprocal Social Interaction in Autism Spectrum Disorder

    Directory of Open Access Journals (Sweden)

    Blythe A Corbett

    2014-10-01

    Full Text Available The hallmark characteristic of autism spectrum disorder (ASD is poor reciprocal social communication. Interventions designed to improve this core deficit are critically needed. Social skills interventions such as direct training, peer mediation, and video modeling have contributed to improvements in various social skills in children with ASD. This paper reviews existing social competence interventions available for children with ASD while highlighting hypothesized critical components for advancing, maintaining and generalizing skills, which include 1 peer mediation, 2 active learning, and 3 implementation in supportive, natural contexts. As a framework for these approaches, this conceptual paper describes SENSE Theatre, a novel intervention that combines trained peers that facilitate the performance-based theatrical treatment delivered in a supportive, community-based environment. A review of previous research shows early feasibility, setting the stage for more rigorous studies to aid in developing a standardized intervention package.

  8. Wnt isoform-specific interactions with coreceptor specify inhibition or potentiation of signaling by LRP6 antibodies.

    Directory of Open Access Journals (Sweden)

    Yan Gong

    Full Text Available β-Catenin-dependent Wnt signaling is initiated as Wnt binds to both the receptor FZD and coreceptor LRP5/6, which then assembles a multimeric complex at the cytoplasmic membrane face to recruit and inactivate the kinase GSK3. The large number and sequence diversity of Wnt isoforms suggest the possibility of domain-specific ligand-coreceptor interactions, and distinct binding sites on LRP6 for Wnt3a and Wnt9b have recently been identified in vitro. Whether mechanistically different interactions between Wnts and coreceptors might mediate signaling remains to be determined. It is also not clear whether coreceptor homodimerization induced extracellularly can activate Wnt signaling, as is the case for receptor tyrosine kinases. We generated monoclonal antibodies against LRP6 with the unexpected ability to inhibit signaling by some Wnt isoforms and potentiate signaling by other isoforms. In cell culture, two antibodies characterized further show reciprocal activities on most Wnts, with one antibody antagonizing and the other potentiating. We demonstrate that these antibodies bind to different regions of LRP6 protein, and inhibition of signaling results from blocking Wnt binding. Antibody-mediated dimerization of LRP6 can potentiate signaling only when a Wnt isoform is also able to bind the complex, presumably recruiting FZD. Endogenous autocrine Wnt signaling in different tumor cell lines can be either antagonized or enhanced by the LRP6 antibodies, indicating expression of different Wnt isoforms. As anticipated from the roles of Wnt signaling in cancer and bone development, antibody activities can also be observed in mice for inhibition of tumor growth and in organ culture for enhancement of bone mineral density. Collectively, our results indicate that separate binding sites for different subsets of Wnt isoforms determine the inhibition or potentiation of signaling conferred by LRP6 antibodies. This complexity of coreceptor-ligand interactions may

  9. [Study of anti-idiotype antibodies to human monoclonal antibody].

    Science.gov (United States)

    Harada, R; Takahashi, N; Owaki, I; Kannagi, R; Endo, N; Morita, N; Inoue, M

    1992-02-01

    A human monoclonal antibody, ll-50 (IgM, lambda), was generated, which reacted specifically with a major of glycolipid present in LS174T colon cancer cells. The glycolipid antigen which reacted with the ll-50 antibody was expected to four sugar residues from its TLC mobility, and it was ascertained that the glycolipid antigen which reacted with ll-50 antibody might be Lc4 antigen [Gal beta 1----3 GLcNAc beta 1----3 Gal beta 1----4 Glc beta 1----1 Cer] judging from TLC immunostaining and ELISA when the reactivity of ll-50 antibody was tested using various pure glycolipids in 3-5 sugar residues as an antigen. Sera in patients with malignant disorders and healthy individuals were analyzed by Sandwich assay of immobilized and biotinylated ll-50 antibody. The serum of the Lc4 antigen recognized by ll-50 antibody was significantly higher in patients with malignant disorders than that in healthy individuals (p less than 0.05). Three mouse monoclonal anti-idiotype antibodies, G3, B3 and C5 (all IgG1), were generated by the immunization of BALB/c mice with ll-50 antibody. These anti-idiotype antibodies specifically bound to to human monoclonal antibody, ll-50 and had a significant inhibitory activity towards the binding of ll-50 antibody to the Lc4 antigen. This indicated that these anti-idiotype antibodies, G3, B3, and C5, were paratope-related anti-idiotype antibodies. G3, B3, and C5 were expected to define the nearest idiotope because they could mutually inhibit ll-50 antibody. Sera in patients with malignant disorders and healthy individuals were analyzed by Sandwich assay of immobilized and biotinylated anti-idiotype antibodies, G3, B3, and C5. As to the ll-50 like antibodies defined by C5 (Id-C5+), the mean serum level in patients with malignant disorders was significantly higher than that in healthy individuals (p less than 0.05). As to the ll-50 like antibodies defined by B3 (Id-B3+), the mean serum level in patients with malignant disorders was significantly higher

  10. A potent human neutralizing antibody Fc-dependently reduces established HBV infections.

    Science.gov (United States)

    Li, Dan; He, Wenhui; Liu, Ximing; Zheng, Sanduo; Qi, Yonghe; Li, Huiyu; Mao, Fengfeng; Liu, Juan; Sun, Yinyan; Pan, Lijing; Du, Kaixin; Ye, Keqiong; Li, Wenhui; Sui, Jianhua

    2017-09-26

    Hepatitis B virus (HBV) infection is a major global health problem. Currently-available therapies are ineffective in curing chronic HBV infection. HBV and its satellite hepatitis D virus (HDV) infect hepatocytes via binding of the preS1 domain of its large envelope protein to sodium taurocholate cotransporting polypeptide (NTCP). Here, we developed novel human monoclonal antibodies that block the engagement of preS1 with NTCP and neutralize HBV and HDV with high potency. One antibody, 2H5-A14, functions at picomolar level and exhibited neutralization-activity-mediated prophylactic effects. It also acts therapeutically by eliciting antibody-Fc-dependent immunological effector functions that impose durable suppression of viral infection in HBV-infected mice, resulting in reductions in the levels of the small envelope antigen and viral DNA, with no emergence of escape mutants. Our results illustrate a novel antibody-Fc-dependent approach for HBV treatment and suggest 2H5-A14 as a novel clinical candidate for HBV prevention and treatment of chronic HBV infection.

  11. Impaired antibody response causes persistence of prototypic T cell-contained virus.

    Directory of Open Access Journals (Sweden)

    Andreas Bergthaler

    2009-04-01

    Full Text Available CD8 T cells are recognized key players in control of persistent virus infections, but increasing evidence suggests that assistance from other immune mediators is also needed. Here, we investigated whether specific antibody responses contribute to control of lymphocytic choriomeningitis virus (LCMV, a prototypic mouse model of systemic persistent infection. Mice expressing transgenic B cell receptors of LCMV-unrelated specificity, and mice unable to produce soluble immunoglobulin M (IgM exhibited protracted viremia or failed to resolve LCMV. Virus control depended on immunoglobulin class switch, but neither on complement cascades nor on Fc receptor gamma chain or Fc gamma receptor IIB. Cessation of viremia concurred with the emergence of viral envelope-specific antibodies, rather than with neutralizing serum activity, and even early nonneutralizing IgM impeded viral persistence. This important role for virus-specific antibodies may be similarly underappreciated in other primarily T cell-controlled infections such as HIV and hepatitis C virus, and we suggest this contribution of antibodies be given consideration in future strategies for vaccination and immunotherapy.

  12. Synthetic positive controls for ELISA test kits for detection of IgA and IgM antibodies to Chlamydia trachomatis

    Directory of Open Access Journals (Sweden)

    O. Y. Galkin

    2015-01-01

    Full Text Available The enzyme-linked immunosorbent assay (ELISA is the most informative and versatile method of serological diagnostics. The possibility of detecting by ELISA specific antibodies of different classes allow to differentiate primary infectious process and its remission, exacerbation and chronic disease (holding of differential diagnosis. This approach is implemented in the methodology for evaluation of patients for presence of humoral immune response against the causative agent of urogenital chlamydiosis. As with other infections immediately after Chlamydia trachomatis infection the specific IgM antibodies are formed, and subsequently basic projective antibodies of IgG class are synthesized. However, at exacerbation of chronic urogenital chlamydiosis specific IgA antibodies can be synthesized. That is why comprehensive evaluation of patients for presence of humoral immune response to Ch. trachomatis involves plasma testing of specific antibodies of all three classes. The essential problem in the production of ELISA diagnostic kits is obtaining of positive control. The classic version of positive control is human blood plasma containing specific antibodies. But specific IgM- and IgA-positive sera are deficit raw materials. This fact can significantly limit the production of diagnostic kits, especially in case of large-scale manufacture. We have suggested methodological approach to use of synthetic positive controls in indirect ELISA kits based on conjugate of normal human IgM (IgA and monoclonal antibodies against major outer membrane protein of Ch. trachomatis. It was found that it’s possible to realize such task by means of NHS ester-maleimide-mediated conjugation (by sulfosuccinimidyl-4-(N-maleimidomethylcyclohexane-1-carboxylate and reductive amination-mediated conjugation (by sodium periodate. It was found that synthetic positive controls obtained by different methods are characterized by higher titer compared to IgM- and IgA-positive high

  13. Protein Adsorption and Layer Formation at the Stainless Steel-Solution Interface Mediates Shear-Induced Particle Formation for an IgG1 Monoclonal Antibody.

    Science.gov (United States)

    Kalonia, Cavan K; Heinrich, Frank; Curtis, Joseph E; Raman, Sid; Miller, Maria A; Hudson, Steven D

    2018-03-05

    Passage of specific protein solutions through certain pumps, tubing, and/or filling nozzles can result in the production of unwanted subvisible protein particles (SVPs). In this work, surface-mediated SVP formation was investigated. Specifically, the effects of different solid interface materials, interfacial shear rates, and protein concentrations on SVP formation were measured for the National Institute of Standards and Technology monoclonal antibody (NISTmAb), a reference IgG1 monoclonal antibody (mAb). A stainless steel rotary piston pump was used to identify formulation and process parameters that affect aggregation, and a flow cell (alumina or stainless steel interface) was used to further investigate the effect of different interface materials and/or interfacial shear rates. SVP particles produced were monitored using flow microscopy or flow cytometry. Neutron reflectometry and a quartz crystal microbalance with dissipation monitoring were used to characterize adsorption and properties of NISTmAb at the stainless steel interface. Pump/shear cell experiments showed that the NISTmAb concentration and interface material had a significant effect on SVP formation, while the effects of interfacial shear rate and passage number were less important. At the higher NISTmAb concentrations, the adsorbed protein became structurally altered at the stainless steel interface. The primary adsorbed layer remained largely undisturbed during flow, suggesting that SVP formation at high NISTmAb concentration was caused by the disruption of patches and/or secondary interactions.

  14. Sensitive Detection of the Natural Killer Cell-Mediated Cytotoxicity of Anti-CD20 Antibodies and Its Impairment by B-Cell Receptor Pathway Inhibitors

    Directory of Open Access Journals (Sweden)

    Floyd Hassenrück

    2018-01-01

    Full Text Available The antibody-dependent cell-mediated cytotoxicity (ADCC of the anti-CD20 monoclonal antibodies (mAbs rituximab and obinutuzumab against the cell line Raji and isolated CLL cells and its potential impairment by kinase inhibitors (KI was determined via lactate dehydrogenase release or calcein retention, respectively, using genetically modified NK92 cells expressing CD16-176V as effector cells. Compared to peripheral blood mononuclear cells, recombinant effector cell lines showed substantial alloreactivity-related cytotoxicity without addition of mAbs but afforded determination of ADCC with reduced interassay variability. The cytotoxicity owing to alloreactivity was less susceptible to interference by KI than the ADCC of anti-CD20 mAbs, which was markedly diminished by ibrutinib, but not by idelalisib. Compared to rituximab, the ADCC of obinutuzumab against primary CLL cells showed approximately 30% higher efficacy and less interference with KI. Irreversible BTK inhibitors at a clinically relevant concentration of 1 μM only weakly impaired the ADCC of anti-CD20 mAbs, with less influence in combinations with obinutuzumab than with rituximab and by acalabrutinib than by ibrutinib or tirabrutinib. In summary, NK cell line-based assays permitted the sensitive detection of ADCC of therapeutic anti-CD20 mAbs against CLL cells and of the interference of KI with this important killing mechanism.

  15. Heterogeneity of neutrophil antibodies in patients with primary Sjögren's syndrome.

    Science.gov (United States)

    Lamour, A; Le Corre, R; Pennec, Y L; Cartron, J; Youinou, P

    1995-11-01

    Our aims were to determine the prevalence of neutrophil antibodies in patients with primary Sjögren's syndrome (pSS), identify their target antigen(s), and evaluate their functional significance. Neutrophil antibodies were detected using an indirect immunofluorescence (IIIF) test and an enzyme-linked immunosorbent assay (ELISA), using recombinant human Fc-gamma receptor (Fc gamma RIIIb) as a capture agent. Luminol-dependent chemiluminescence was then measured by an established technique. Antibodies to neutrophils were detected in 30 of 66 patients (45%) and categorized on the basis of positivity for the two assays: IIF+/ELISA+ (group A: five patients), IIF+/ELISA- (group B: five patients), and IFF-/ELISA+ (group C: 20 patients). All positive sera contained antibodies directed to the neutrophil specific Fc gamma RIIIb, and none of them bound to NAnull neutrophils. The titer of neutrophil-reactive antibodies (groups A and B) showed no correlation with the neutrophil count, but these autoantibodies did reduce the cell ability to generate a respiratory burst. Thus, neutrophil antibodies are common in patients with pSS. Their main target appears to be Fc gamma RIII, and this may partly account for the dysfunction in Fc gamma R-mediated clearance by the reticuloendothelial system reported in these patients.

  16. An Anti-C1s Monoclonal, TNT003, Inhibits Complement Activation Induced by Antibodies Against HLA.

    Science.gov (United States)

    Thomas, K A; Valenzuela, N M; Gjertson, D; Mulder, A; Fishbein, M C; Parry, G C; Panicker, S; Reed, E F

    2015-08-01

    Antibody-mediated rejection (AMR) of solid organ transplants (SOT) is characterized by damage triggered by donor-specific antibodies (DSA) binding donor Class I and II HLA (HLA-I and HLA-II) expressed on endothelial cells. While F(ab')2 portions of DSA cause cellular activation and proliferation, Fc regions activate the classical complement cascade, resulting in complement deposition and leukocyte recruitment, both hallmark features of AMR. We characterized the ability of an anti-C1s monoclonal antibody, TNT003, to inhibit HLA antibody (HLA-Ab)-induced complement activation. Complement deposition induced by HLA-Ab was evaluated using novel cell- and bead-based assays. Human aortic endothelial cells (HAEC) were cultured with HLA-Ab and human complement; production of activated complement proteins was measured by flow cytometry. Additionally, C3d deposition was measured on single antigen beads (SAB) mixed with HLA-Ab and human complement. TNT003 inhibited HLA-Ab mediated complement deposition on HAEC in a concentration-dependent manner; C3a, C4a and C5a anaphylatoxin production was also diminished by TNT003. Finally, TNT003 blocked C3d deposition induced by Class I (HLAI-Ab)- and Class II (HLAII-Ab)-specific antibodies on SAB. These data suggest TNT003 may be useful for modulating the effects of DSA, as TNT003 inhibits complement deposition and split product formation generated by HLA-I/II-Ab in vitro. © 2015 The Authors. American Journal of Transplantation Published by Wiley Periodicals, Inc.

  17. Impact of pretransplant anti-HLA antibodies on outcomes in lung transplant candidates.

    Science.gov (United States)

    Kim, Miae; Townsend, Keri R; Wood, Isabelle G; Boukedes, Steve; Guleria, Indira; Gabardi, Steven; El-Chemaly, Souheil; Camp, Phillip C; Chandraker, Anil K; Milford, Edgar L; Goldberg, Hilary J

    2014-05-15

    The prevalence of anti-HLA antibodies in lung transplant candidates and their impact on waitlist and transplant outcomes is not known. We examined the prevalence of pretransplant anti-HLA antibodies at varying thresholds and evaluated their impact on outcomes before and after lung transplantation. We performed a single-center retrospective cohort study including all patients listed for lung transplantation between January 2008 and August 2012. Per protocol, transplant candidates were assessed by solid phase LABscreen mixed Class I and II and LABscreen Single Antigen assays. Among 224 patients, 34% had anti-HLA antibodies at mean fluorescent intensity (MFI) greater than or equal to 3,000 (group III), and 24% had antibodies at MFI 1,000 to 3,000 (group II). Ninety percent of the patients with pretransplant anti-HLA antibodies had class I antibodies, whereas only seven patients developed class II alone. Patients in group III were less likely to receive transplants than patients without any anti-HLA antibodies (group I) (45.5 vs. 67.7%, P = 0.005). Wait time to transplant was longer in group III than group I, although this difference did not meet statistical significance, and waitlist mortality was similar. Among transplant recipients, antibody-mediated rejection (AMR) was more frequent in group III than in group II (20% vs. 0%, P = 0.01) or group I (6.3%, P = 0.05). The presence of anti-HLA antibodies at the high MFI threshold (>3,000) was associated with lower transplant rate and higher rates of AMR. Screening for anti-HLA antibodies using the 3,000 MFI threshold may be important in managing transplant candidates and recipients.

  18. Anti-Plasmodium falciparum invasion ligand antibodies in a low malaria transmission region, Loreto, Peru

    DEFF Research Database (Denmark)

    Villasis, Elizabeth; Lopez-Perez, Mary; Torres, Katherine

    2012-01-01

    Background: Erythrocyte invasion by Plasmodium falciparum is a complex process that involves two families; Erythrocyte Binding-Like (EBL) and the Reticulocyte Binding-Like (PfRh) proteins. Antibodies that inhibit merozoite attachment and invasion are believed to be important in mediating naturall...

  19. Antithyroid microsomal antibody

    Science.gov (United States)

    Thyroid antimicrosomal antibody; Antimicrosomal antibody; Microsomal antibody; Thyroid peroxidase antibody; TPOAb ... Granulomatous thyroiditis Hashimoto thyroiditis High levels of these antibodies have also been linked with an increased risk ...

  20. Elaborative Retrieval: Do Semantic Mediators Improve Memory?

    Science.gov (United States)

    Lehman, Melissa; Karpicke, Jeffrey D.

    2016-01-01

    The elaborative retrieval account of retrieval-based learning proposes that retrieval enhances retention because the retrieval process produces the generation of semantic mediators that link cues to target information. We tested 2 assumptions that form the basis of this account: that semantic mediators are more likely to be generated during…

  1. DE71 suppresses thyroid hormone-mediated dendritogenesis and ...

    African Journals Online (AJOL)

    olayemitoyin

    Summary: Polybrominated diphenylethers (PBDEs) are synthesized ... Taken together, our study clearly reveals that DE71 can impair TH-mediated .... calbindin-28 K antibody and fluorescein ... spectral type inverted microscope IX81, ..... Steppan, L., Kerkvliet, N.I. (1994). ... Toxicology 86: 49-61. ... Ph.D. Dissertation.

  2. Fusion proteins of HIV-1 envelope glycoprotein gp120 with CD4-induced antibodies showed enhanced binding to CD4 and CD4 binding site antibodies

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Weizao, E-mail: chenw3@mail.nih.gov [Protein Interactions Group, Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702 (United States); Feng, Yang [Protein Interactions Group, Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702 (United States); Wang, Yanping [Protein Interactions Group, Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702 (United States); The Basic Research Program, Science Applications International Corporation-Frederick, Inc., National Cancer Institute, National Institutes of Health, Frederick, MD 21702 (United States); Zhu, Zhongyu; Dimitrov, Dimiter S. [Protein Interactions Group, Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702 (United States)

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer Some recombinant HIV-1 gp120s do not preserve their conformations on gp140s. Black-Right-Pointing-Pointer We hypothesize that CD4i antibodies could induce conformational changes in gp120. Black-Right-Pointing-Pointer CD4i antibodies enhance binding of CD4 and CD4bs antibodies to gp120. Black-Right-Pointing-Pointer CD4i antibody-gp120 fusion proteins could have potential as vaccine immunogens. -- Abstract: Development of successful AIDS vaccine immunogens continues to be a major challenge. One of the mechanisms by which HIV-1 evades antibody-mediated neutralizing responses is the remarkable conformational flexibility of its envelope glycoprotein (Env) gp120. Some recombinant gp120s do not preserve their conformations on gp140s and functional viral spikes, and exhibit decreased recognition by CD4 and neutralizing antibodies. CD4 binding induces conformational changes in gp120 leading to exposure of the coreceptor-binding site (CoRbs). In this study, we test our hypothesis that CD4-induced (CD4i) antibodies, which target the CoRbs, could also induce conformational changes in gp120 leading to better exposed conserved neutralizing antibody epitopes including the CD4-binding site (CD4bs). We found that a mixture of CD4i antibodies with gp120 only weakly enhanced CD4 binding. However, such interactions in single-chain fusion proteins resulted in gp120 conformations which bound to CD4 and CD4bs antibodies better than the original or mutagenically stabilized gp120s. Moreover, the two molecules in the fusion proteins synergized with each other in neutralizing HIV-1. Therefore, fusion proteins of gp120 with CD4i antibodies could have potential as components of HIV-1 vaccines and inhibitors of HIV-1 entry, and could be used as reagents to explore the conformational flexibility of gp120 and mechanisms of entry and immune evasion.

  3. Brain-relevant antibodies in first-episode psychosis: a matched case-control study.

    Science.gov (United States)

    Gaughran, Fiona; Lally, John; Beck, Katherine; McCormack, Ruaidhri; Gardner-Sood, Poonam; Coutinho, Ester; Jacobson, Leslie; Lang, Bethan; Sainz-Fuertes, Ricardo; Papanastasiou, Evangelos; Di Forti, Marta; Nicholson, Tim; Vincent, Angela; Murray, Robin M

    2018-06-01

    There has been much recent excitement about the possibility that some cases of psychosis may be wholly due to brain-reactive antibodies, with antibodies to N-methyl-D-aspartate receptor (NMDAR) and the voltage-gated potassium channel (VGKC)-complex reported in a few patients with first-episode psychosis (FEP). Participants were recruited from psychiatric services in South London, UK, from 2009 to 2011 as part of the Genetics and Psychosis study. We conducted a case-control study to examine NMDAR and VGKC-complex antibody levels and rates of antibody positivity in 96 patients presenting with FEP and 98 controls matched for age and sex. Leucine-rich glioma inactiviated-1 (LGI1) and contactin-associated protein (CASPR) antibodies were also measured. Notably, patients with suspicion of organic disease were excluded. VGKC-complex antibodies were found in both cases (n = 3) and controls (n = 2). NMDAR antibody positivity was seen in one case and one control. Either LGI1-Abs or CASPR2-Abs were found in three cases and three controls. Neuronal antibody staining, consistent with the above results or indicating potential novel antigens, was overall positive in four patients but also in six controls. Overall, antibody positivity was at low levels only and not higher in cases than in controls. This case-control study of the prevalence of antibodies in FEP does not provide evidence to support the hypothesis that FEP is associated with an immune-mediated process in a subgroup of patients. Nevertheless, as other bio-clinical factors may influence the effect of such antibodies in a given individual, and patients with organic neurological disease may be misdiagnosed as FEP, the field requires more research to put these findings in context.

  4. Are Improvements in Cognitive Content and Depressive Symptoms Correlates or Mediators during Acute-Phase Cognitive Therapy for Recurrent Major Depressive Disorder?

    Science.gov (United States)

    Vittengl, Jeffrey R; Clark, Lee Anna; Thase, Michael E; Jarrett, Robin B

    2014-01-09

    The cognitive model of depression posits that cognitive therapy's (CT) effect on depressive symptoms is mediated by changes in cognitive content (e.g., automatic negative thoughts dysfunctional attitudes, failure attributions). We tested improvement and normalization of cognitive content among outpatients ( N = 523) with recurrent major depressive disorder treated with acute-phase CT (Jarrett & Thase, 2010; Jarrett et al., 2013). We also tested whether improvement in cognitive content accounted for subsequent changes in depressive symptoms and vice versa. Five measures of content improved substantively from pre- to post-CT (median d = 0.96), and the proportions of patients scoring in "healthy" ranges increased (median 45% to 82%). Evidence for cognitive mediation of symptom reduction was limited (median r = .06), as was evidence for symptom mediation of cognitive content improvement (median r = .07). We discuss measurement and design issues relevant to detection of mediators and consider alternative theories of change.

  5. Effects of altered FcγR binding on antibody pharmacokinetics in cynomolgus monkeys

    Science.gov (United States)

    Leabman, Maya K; Meng, Y Gloria; Kelley, Robert F; DeForge, Laura E; Cowan, Kyra J; Iyer, Suhasini

    2013-01-01

    Antibody interactions with Fcγ receptors (FcγRs), like FcγRIIIA, play a critical role in mediating antibody effector functions and thereby contribute significantly to the biologic and therapeutic activity of antibodies. Over the past decade, considerable work has been directed towards production of antibodies with altered binding affinity to FcγRs and evaluation of how the alterations modulate their therapeutic activity. This has been achieved by altering glycosylation status at N297 or by engineering modifications in the crystallizable fragment (Fc) region. While the effects of these modifications on biologic activity and efficacy have been examined, few studies have been conducted to understand their effect on antibody pharmacokinetics (PK). We present here a retrospective analysis in which we characterize the PK of three antibody variants with decreased FcγR binding affinity caused by amino acid substitutions in the Fc region (N297A, N297G, and L234A/L235A) and three antibody variants with increased FcγRIIIA binding affinity caused by afucosylation at N297, and compare their PK to corresponding wild type antibody PK in cynomolgus monkeys. For all antibodies, PK was examined at a dose that was known to be in the linear range. Since production of the N297A and N297G variants in Chinese hamster ovary cells results in aglycosylated antibodies that do not bind to FcγRs, we also examined the effect of expression of an aglycosylated antibody, without sequence change(s), in E. coli. All the variants demonstrated similar PK compared with that of the wild type antibodies, suggesting that, for the six antibodies presented here, altered FcγR binding affinity does not affect PK. PMID:24492343

  6. Antiprothrombin Antibodies

    Directory of Open Access Journals (Sweden)

    Polona Žigon

    2015-05-01

    Full Text Available In patients with the antiphospholipid syndrome (APS, the presence of a group of pathogenic autoantibodies called antiphospholipid antibodies causes thrombosis and pregnancy complications. The most frequent antigenic target of antiphospholipid antibodies are phospholipid bound β2-glycoprotein 1 (β2GPI and prothrombin. The international classification criteria for APS connect the occurrence of thrombosis and/or obstetric complications together with the persistence of lupus anticoagulant, anti-cardiolipin antibodies (aCL and antibodies against β2GPI (anti-β2GPI into APS. Current trends for the diagnostic evaluation of APS patients propose determination of multiple antiphospholipid antibodies, among them also anti-prothrombin antibodies, to gain a common score which estimates the risk for thrombosis in APS patients. Antiprothrombin antibodies are common in APS patients and are sometimes the only antiphospholipid antibodies being elevated. Methods for their determination differ and have not yet been standardized. Many novel studies confirmed method using phosphatidylserine/prothrombin (aPS/PT ELISA as an antigen on solid phase encompass higher diagnostic accuracy compared to method using prothrombin alone (aPT ELISA. Our research group developed an in-house aPS/PT ELISA with increased analytical sensitivity which enables the determination of all clinically relevant antiprothrombin antibodies. aPS/PT exhibited the highest percentage of lupus anticoagulant activity compared to aCL and anti-β2GPI. aPS/PT antibodies measured with the in-house method associated with venous thrombosis and presented the strongest independent risk factor for the presence of obstetric complications among all tested antiphospholipid antibodies

  7. Pre-existing neutralizing antibody mitigates B cell dysregulation and enhances the Env-specific antibody response in SHIV-infected rhesus macaques.

    Directory of Open Access Journals (Sweden)

    Juan Pablo Jaworski

    Full Text Available Our central hypothesis is that protection against HIV infection will be powerfully influenced by the magnitude and quality of the B cell response. Although sterilizing immunity, mediated by pre-formed abundant and potent antibodies is the ultimate goal for B cell-targeted HIV vaccine strategies, scenarios that fall short of this may still confer beneficial defenses against viremia and disease progression. We evaluated the impact of sub-sterilizing pre-existing neutralizing antibody on the B cell response to SHIV infection. Adult male rhesus macaques received passive transfer of a sub-sterilizing amount of polyclonal neutralizing immunoglobulin (Ig purified from previously infected animals (SHIVIG or control Ig prior to intra-rectal challenge with SHIVSF162P4 and extensive longitudinal sampling was performed. SHIVIG treated animals exhibited significantly reduced viral load and increased de novo Env-specific plasma antibody. Dysregulation of the B cell profile was grossly apparent soon after infection in untreated animals; exemplified by a ≈50% decrease in total B cells in the blood evident 2-3 weeks post-infection which was not apparent in SHIVIG treated animals. IgD+CD5+CD21+ B cells phenotypically similar to marginal zone-like B cells were highly sensitive to SHIV infection, becoming significantly decreased as early as 3 days post-infection in control animals, while being maintained in SHIVIG treated animals, and were highly correlated with the induction of Env-specific plasma antibody. These results suggest that B cell dysregulation during the early stages of infection likely contributes to suboptimal Env-specific B cell and antibody responses, and strategies that limit this dysregulation may enhance the host's ability to eliminate HIV.

  8. Co-evolution of affinity and stability of grafted amyloid-motif domain antibodies.

    Science.gov (United States)

    Julian, Mark C; Lee, Christine C; Tiller, Kathryn E; Rabia, Lilia A; Day, Evan K; Schick, Arthur J; Tessier, Peter M

    2015-10-01

    An attractive approach for designing lead antibody candidates is to mimic natural protein interactions by grafting peptide recognition motifs into the complementarity-determining regions (CDRs). We are using this approach to generate single-domain (VH) antibodies specific for amyloid-forming proteins such as the Alzheimer's Aβ peptide. Here, we use random mutagenesis and yeast surface display to improve the binding affinity of a lead VH domain grafted with Aβ residues 33-42 in CDR3. Interestingly, co-selection for improved Aβ binding and VH display on the surface of yeast yields antibody domains with improved affinity and reduced stability. The highest affinity VH domains were strongly destabilized on the surface of yeast as well as unfolded when isolated as autonomous domains. In contrast, stable VH domains with improved affinity were reliably identified using yeast surface display by replacing the display antibody that recognizes a linear epitope tag at the terminus of both folded and unfolded VH domains with a conformational ligand (Protein A) that recognizes a discontinuous epitope on the framework of folded VH domains. Importantly, we find that selection for improved stability using Protein A without simultaneous co-selection for improved Aβ binding leads to strong enrichment for stabilizing mutations that reduce antigen binding. Our findings highlight the importance of simultaneously optimizing affinity and stability to improve the rapid isolation of well-folded and specific antibody fragments. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  9. Human antibody fragments specific for the epidermal growth factor receptor selected from large non-immunised phage display libraries.

    Science.gov (United States)

    Souriau, Christelle; Rothacker, Julie; Hoogenboom, Hennie R; Nice, Edouard

    2004-09-01

    Antibodies to EGFR have been shown to display anti-tumour effects mediated in part by inhibition of cellular proliferation and angiogenesis, and by enhancement of apoptosis. Humanised antibodies are preferred for clinical use to reduce complications with HAMA and HAHA responses frequently seen with murine and chimaeric antibodies. We have used depletion and subtractive selection strategies on cells expressing the EGFR to sample two large antibody fragment phage display libraries for the presence of human antibodies which are specific for the EGFR. Four Fab fragments and six scFv fragments were identified, with affinities of up to 2.2nM as determined by BIAcore analysis using global fitting of the binding curves to obtain the individual rate constants (ka and kd). This overall approach offers a generic screening method for the identification of growth factor specific antibodies and antibody fragments from large expression libraries and has potential for the rapid development of new therapeutic and diagnostic reagents.

  10. Monoclonal antibodies against the iron regulated outer membrane Proteins of Acinetobacter baumannii are bactericidal

    Directory of Open Access Journals (Sweden)

    Goel Vikas

    2001-08-01

    Full Text Available Abstract Background Iron is an important nutrient required by all forms of life.In the case of human hosts,the free iron availability is 10-18M,which is far less than what is needed for the survival of the invading bacterial pathogen.To survive in such conditions, bacteria express new proteins in their outer membrane and also secrete iron chelators called siderophores. Results/ Discussion Acinetobacter baumannii ATCC 19606, a nosocomial pathogen which grows under iron restricted conditions, expresses four new outer membrane proteins,with molecular weight ranging from 77 kDa to 88 kDa, that are called Iron Regulated Outer Membrane Proteins (IROMPs. We studied the functional and immunological properties of IROMPs expressed by A.baumanii ATCC 19606.The bands corresponding to IROMPs were eluted from SDS-PAGE and were used to immunize BALB/c mice for the production of monoclonal antibodies. Hybridomas secreting specific antibodies against these IROMPs were selected after screening by ELISA and their reactivity was confirmed by Western Blot. The antibodies then generated belonged to IgM isotype and showed bactericidical and opsonising activities against A.baumanii in vitro.These antibodies also blocked siderophore mediated iron uptake via IROMPs in bacteria. Conclusion This proves that iron uptake via IROMPs,which is mediated through siderophores,may have an important role in the survival of A.baumanii inside the host,and helps establishing the infection.

  11. RosettaAntibodyDesign (RAbD): A general framework for computational antibody design.

    Science.gov (United States)

    Adolf-Bryfogle, Jared; Kalyuzhniy, Oleks; Kubitz, Michael; Weitzner, Brian D; Hu, Xiaozhen; Adachi, Yumiko; Schief, William R; Dunbrack, Roland L

    2018-04-01

    amino acid types for residues that contact the antigen in the native structures was 72% in simulations performed in the presence of the antigen and 48% in simulations performed without the antigen, for an ARR of 1.5. For the non-contacting residues, the ARR was 1.08. This shows that the sequence profiles are able to maintain the amino acid types of these conserved, buried sites, while recovery of the exposed, contacting residues requires the presence of the antigen-antibody interface. We tested RAbD experimentally on both a lambda and kappa antibody-antigen complex, successfully improving their affinities 10 to 50 fold by replacing individual CDRs of the native antibody with new CDR lengths and clusters.

  12. Anti-HMGCR antibodies as a biomarker for immune-mediated necrotizing myopathies: A history of statins and experience from a large international multi-center study.

    Science.gov (United States)

    Musset, Lucile; Allenbach, Yves; Benveniste, Olivier; Boyer, Olivier; Bossuyt, Xavier; Bentow, Chelsea; Phillips, Joe; Mammen, Andrew; Van Damme, Philip; Westhovens, René; Ghirardello, Anna; Doria, Andrea; Choi, May Y; Fritzler, Marvin J; Schmeling, Heinrike; Muro, Yoshinao; García-De La Torre, Ignacio; Ortiz-Villalvazo, Miguel A; Bizzaro, Nicola; Infantino, Maria; Imbastaro, Tiziana; Peng, Qinglin; Wang, Guochun; Vencovský, Jiří; Klein, Martin; Krystufkova, Olga; Franceschini, Franco; Fredi, Micaela; Hue, Sophie; Belmondo, Thibaut; Danko, Katalin; Mahler, Michael

    2016-10-01

    In an effort to find naturally occurring substances that reduce cholesterol by inhibiting 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), statins were first discovered by Endo in 1972. With the widespread prescription and use of statins to decrease morbidity from myocardial infarction and stroke, it was noted that approximately 5% of all statin users experienced muscle pain and weakness during treatment. In a smaller proportion of patients, the myopathy progressed to severe morbidity marked by proximal weakness and severe muscle wasting. Remarkably, Mammen and colleagues were the first to discover that the molecular target of statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), is an autoantibody target in patients that develop an immune-mediated necrotizing myopathy (IMNM). These observations have been confirmed in a number of studies but, until today, a multi-center, international study of IMNM, related idiopathic inflammatory myopathies (IIM), other auto-inflammatory conditions and controls has not been published. Accordingly, an international, multi-center study investigated the utility of anti-HMGCR antibodies in the diagnosis of statin-associated IMNM in comparison to different forms of IIM and controls. This study included samples from patients with different forms of IIM (n=1250) and patients with other diseases (n=656) that were collected from twelve sites and tested for anti-HMGCR antibodies by ELISA. This study confirmed that anti-HMGCR autoantibodies, when found in conjunction with statin use, characterize a subset of IIM who are older and have necrosis on muscle biopsy. Taken together, the data to date indicates that testing for anti-HMGCR antibodies is important in the differential diagnosis of IIM and might be considered for future classification criteria. Copyright © 2016. Published by Elsevier B.V.

  13. A Multiplex Microsphere-Based Immunoassay Increases the Sensitivity of SIV-Specific Antibody Detection in Serum Samples and Mucosal Specimens Collected from Rhesus Macaques Infected with SIVmac239

    OpenAIRE

    Powell, Rebecca L.R.; Ouellette, Ian; Lindsay, Ross W.; Parks, Christopher L.; King, C. Richter; McDermott, Adrian B.; Morrow, Gavin

    2013-01-01

    Abstract Results from recent HIV-1 vaccine studies have indicated that high serum antibody (Ab) titers may not be necessary for Ab-mediated protection, and that Abs localized to mucosal sites might be critical for preventing infection. Enzyme-linked immunosorbent assay (ELISA) has been used for decades as the gold standard for Ab measurement, though recently, highly sensitive microsphere-based assays have become available, with potential utility for improved detection of Abs. In this study, w...

  14. Antibodies against glycolipids enhance antifungal activity of macrophages and reduce fungal burden after infection with Paracoccidioides brasiliensis

    Directory of Open Access Journals (Sweden)

    Renata Amelia eBueno

    2016-02-01

    Full Text Available Paracoccidioidomycosis is a fungal disease endemic in Latin America. Polyclonal antibodies to acidic glycosphingolipids (GSLs from Paracoccidioides brasiliensis opsonized yeast forms in vitro increasing phagocytosis and reduced the fungal burden of infected animals. Antibodies to GSL were active in both prophylactic and therapeutic protocols using a murine intratracheal infection model. Pathological examination of the lungs of animals treated with antibodies to GSL showed well-organized granulomas and minimally damaged parenchyma compared to the untreated control. Murine peritoneal macrophages activated by IFN-γ and incubated with antibodies against acidic GSLs more effectively phagocytosed and killed P. brasiliensis yeast cells as well as produced more nitric oxide compared to controls. The present work discloses a novel target of protective antibodies against P. brasiliensis adding to other well-studied mediators of the immune response to this fungus.

  15. The anti-epidermal growth factor receptor (EGFR) monoclonal antibody, C225, enhances radiation-induced apoptosis in primary glioma cell lines through mediation of MAPK/JNK/p38 signaling pathways

    International Nuclear Information System (INIS)

    Chakravarti, A.; Noll, E.; Black, P.M.; Loeffler, J.S.

    2001-01-01

    Purpose: Increasing evidence suggests that signaling mediated by the epidermal growth factor receptor (EGFR) pathway contributes to radiation resistance. The anti-EGFR monoclonal antibody, C225, has been shown to enhance radiation response for several tumor types in preclinical models. Malignant gliomas are known to express, and quite frequently overexpress, EGFR. Our objectives in this study were to 1) Evaluate the efficacy of C225 as a radiation response modifier in EGFR-expressing glioma cell lines and to 2) Investigate the underlying molecular mechanisms mediating C225-induced enhancement of radiation response. Materials and Methods: Twelve EGFR-expressing glioma cells lines, established from patient tumors, were used for this study. Cells were incubated with C225, irradiated, and then evaluated for radiation response. Assays used to evaluate efficacy of C225-mediated radiosensitization included time-course apoptosis assays (Annexin V and TUNEL), viability assays (MTT), and clonogenic survival assays. The changes along MAPK (p44/p42)/JNK/p38-MAPK signal transduction pathways were then investigated using quantitative Western analysis with phospho-specific antibodies to determine the molecular mechanisms by which C225 mediates a given response. Results: C225 clearly enhanced radiation response for 7 of the 12 primary glioma cell lines studied. Enhancement of both immediate and delayed apoptotic responses was evident in these 7 responsive cell lines after C225 administration. The average apoptosis index at 6 hours post-RT+C225 for the 7 responsive lines was 9.5%, compared to 1.2% for the RT-only controls. A pattern of delayed apoptosis was evident in these 7 lines, with secondary apoptotic peaks (∼ 8.0%) occurring at 24 hours post-RT+C225. Time course viability measurements revealed a steady decrease in viable tumor cells in these responsive cell lines from 75% at 6 hours post-RT+C225 to 20% at 7 days. Clonogenic survival was also diminished in these 7 lines

  16. Antibodies against Marinobacter algicola and Salmonella typhimurium flagellins do not cross-neutralize TLR5 activation.

    Directory of Open Access Journals (Sweden)

    Raul Terron-Exposito

    Full Text Available Flagellins evoke strong innate and adaptive immune responses. These proteins may play a key role as radioprotectors, exert antitumoral activity in certain types of tumor and reduce graft-versus-host disease in allogeneic hematopoietic stem cell transplant recipients. Notwithstanding, flagellins are highly immunogenic, and repeated use leads to their neutralization by systemic antibodies. This neutralization is not prevented by using functional deleted flagellins. These observations led us to explore the possibility of preventing initial neutralization by means of another functional flagellin that does not belong to common pathogenic bacteria but that has the capacity to activate TLR5. Here we characterized the functional capacity of the two-phase Marinobacter algicola (MA-derived flagellins (F and FR as systemic and mucosal adjuvants and compared their performance with that of Salmonella typhimurium (STF flagellins (FljB and FliC. We also report for the first time on the in vitro and in vivo capacity of various flagellins to trigger TLR5 activation in the presence of species-specific anti-flagellin antibodies, the cross-neutralization mediated by these antibodies, and the sequential use of these flagellins for TLR5 activation. Our results showed that MA flagellins behave in a similar way to STF ones, inducing pro-inflammatory cytokines (IL8, CCL20, CCL2 and evoking a strong in vivo antibody response against a model epitope. More importantly, MA flagellins were fully functional, in vitro or in vivo, in the presence of a high concentration of neutralizing anti-flagellin STF antibodies, and STF flagellin was not inhibited by neutralizing anti-flagellin MA antibodies. The use of active flagellins from distinct bacteria could be a useful approach to prevent systemic neutralization of this group of adjuvants and to facilitate the rational design of flagellin-based vaccines and/or other therapeutic treatments (against ischemia, acute renal failure

  17. Nanobodies and Nanobody-Based Human Heavy Chain Antibodies As Antitumor Therapeutics

    Directory of Open Access Journals (Sweden)

    Peter Bannas

    2017-11-01

    Full Text Available Monoclonal antibodies have revolutionized cancer therapy. However, delivery to tumor cells in vivo is hampered by the large size (150 kDa of conventional antibodies. The minimal target recognition module of a conventional antibody is composed of two non-covalently associated variable domains (VH and VL. The proper orientation of these domains is mediated by their hydrophobic interface and is stabilized by their linkage to disulfide-linked constant domains (CH1 and CL. VH and VL domains can be fused via a genetic linker into a single-chain variable fragment (scFv. scFv modules in turn can be fused to one another, e.g., to generate a bispecific T-cell engager, or they can be fused in various orientations to antibody hinge and Fc domains to generate bi- and multispecific antibodies. However, the inherent hydrophobic interaction of VH and VL domains limits the stability and solubility of engineered antibodies, often causing aggregation and/or mispairing of V-domains. Nanobodies (15 kDa and nanobody-based human heavy chain antibodies (75 kDa can overcome these limitations. Camelids naturally produce antibodies composed only of heavy chains in which the target recognition module is composed of a single variable domain (VHH or Nb. Advantageous features of nanobodies include their small size, high solubility, high stability, and excellent tissue penetration in vivo. Nanobodies can readily be linked genetically to Fc-domains, other nanobodies, peptide tags, or toxins and can be conjugated chemically at a specific site to drugs, radionuclides, photosensitizers, and nanoparticles. These properties make them particularly suited for specific and efficient targeting of tumors in vivo. Chimeric nanobody-heavy chain antibodies combine advantageous features of nanobodies and human Fc domains in about half the size of a conventional antibody. In this review, we discuss recent developments and perspectives for applications of nanobodies and nanobody

  18. Nanobodies and Nanobody-Based Human Heavy Chain Antibodies As Antitumor Therapeutics.

    Science.gov (United States)

    Bannas, Peter; Hambach, Julia; Koch-Nolte, Friedrich

    2017-01-01

    Monoclonal antibodies have revolutionized cancer therapy. However, delivery to tumor cells in vivo is hampered by the large size (150 kDa) of conventional antibodies. The minimal target recognition module of a conventional antibody is composed of two non-covalently associated variable domains (VH and VL). The proper orientation of these domains is mediated by their hydrophobic interface and is stabilized by their linkage to disulfide-linked constant domains (CH1 and CL). VH and VL domains can be fused via a genetic linker into a single-chain variable fragment (scFv). scFv modules in turn can be fused to one another, e.g., to generate a bispecific T-cell engager, or they can be fused in various orientations to antibody hinge and Fc domains to generate bi- and multispecific antibodies. However, the inherent hydrophobic interaction of VH and VL domains limits the stability and solubility of engineered antibodies, often causing aggregation and/or mispairing of V-domains. Nanobodies (15 kDa) and nanobody-based human heavy chain antibodies (75 kDa) can overcome these limitations. Camelids naturally produce antibodies composed only of heavy chains in which the target recognition module is composed of a single variable domain (VHH or Nb). Advantageous features of nanobodies include their small size, high solubility, high stability, and excellent tissue penetration in vivo . Nanobodies can readily be linked genetically to Fc-domains, other nanobodies, peptide tags, or toxins and can be conjugated chemically at a specific site to drugs, radionuclides, photosensitizers, and nanoparticles. These properties make them particularly suited for specific and efficient targeting of tumors in vivo . Chimeric nanobody-heavy chain antibodies combine advantageous features of nanobodies and human Fc domains in about half the size of a conventional antibody. In this review, we discuss recent developments and perspectives for applications of nanobodies and nanobody-based human heavy

  19. Antibody guided diagnosis and therapy of brain gliomas using radiolabeled monoclonal antibodies against epidermal growth factor receptor and placental alkaline phosphatase

    International Nuclear Information System (INIS)

    Kalofonos, H.P.; Pawlikowska, T.R.; Hemingway, A.

    1989-01-01

    Twenty-seven patients with brain glioma were scanned using 123 I-labeled monoclonal antibodies against epidermal growth factor receptor (EGFR1) or placental alkaline phosphatase (H17E2). Successful localization was achieved in 18 out of 27 patients. Eleven out of 27 patients were also studied using a nonspecific control antibody (11.4.1) of the same immunoglobulin subclass and observable tumor localization was also achieved in five patients. The specificity of targeting was assessed by comparing images obtained with specific and nonspecific antibodies and by examining tumor and normal tissue biopsies after dual antibody administration. Ten patients with recurrent grade III or IV glioma who showed good localization of radiolabeled antibody were treated with 40-140 mCi of 131 I-labeled antibody delivered to the tumor area intravenously (n = 5) or by infusion into the internal carotid artery (n = 5). Six patients showed clinical improvement lasting from 6 mo to 3 yr. One patient continues in remission (3 yr after therapy), but the other five who responded initially relapsed 6-9 mo after therapy and died. No major toxicity was attributable to antibody-guided irradiation. Targeted irradiation by monoclonal antibody may be clinically useful and should be explored further in the treatment of brain gliomas resistant to conventional forms of treatment

  20. Lipid-mediated protein functionalization of electrospun polycaprolactone fibers

    Directory of Open Access Journals (Sweden)

    C. Cohn

    2016-05-01

    Full Text Available In this study, electrospun polycaprolactone (PCL fibers are plasma-treated and chemically conjugated with cholesteryl succinyl silane (CSS. In addition to Raman spectroscopy, an immobilization study of DiO as a fluorescent probe of lipid membranes provides evidence supporting the CSS coating of plasma-treated PCL fibers. Further, anti-CD20 antibodies are used as a model protein to evaluate the potential of lipid-mediated protein immobilization as a mechanism to functionalize the CSS-PCL fiber scaffolds. Upon anti-CD20 functionalization, the CSS-PCL fiber scaffolds capture Granta-22 cells 2.4 times more than the PCL control does, although the two fiber scaffolds immobilize a comparable amount of anti-CD20. Taken together, results from the present study demonstrate that the CSS coating and CSS-mediated antibody immobilization offers an appealing strategy to functionalize electrospun synthetic polymer fibers and confer cell-specific functions on the fiber scaffolds, which can be mechanically robust but often lack biological functions.

  1. Improving quality-of-life outcomes for patients with cancer through mediating effects of depressive symptoms and functional status: a three-path mediation model.

    Science.gov (United States)

    Hsu, Mei-Chi; Tu, Chun-Hsien

    2014-09-01

    To test a hypothetical three-path mediation model evaluating the effects of functional status and depressive symptoms on the relationship between fatigue and quality of life in patients with cancer on the basis of the Theory of Unpleasant Symptoms. Patients with cancer often experience two or more concurrent, interrelated, mutually influential symptoms. Multiple unpleasant symptoms that have been proposed as mediating variables affecting quality of life in a model proposed in recent cancer studies are scanty. This study was a cross-sectional, descriptive, correlational design. Three hundred and twenty-six patients with cancer from oncology clinics were recruited in Taiwan between 2010-2011. Mediation models were tested and confirmed by applying structural modelling using Analysis of Moment Structures and the joint significance test. Fatigue affects patient quality of life directly or indirectly through functional status and depressive symptoms. These two mediating variables exhibited direct effects on quality of life. A path analysis approach revealed that 47·28 and 67·70% of the total effects of functional status and depressive symptoms, respectively, on the quality-of-life mediation models are attributable to 29·6 and 44·7% of the total effects between fatigue and quality of life, which mediated through two mediators, respectively. Quality of life may be enhanced by simultaneously improving physiological and psychological factors. An understanding of mediating effects is valuable in nursing care of patients with cancer, particularly in the early phase of treatment or in newly diagnosed stages I-III or recently treated patients with cancer in different disease stages. © 2013 John Wiley & Sons Ltd.

  2. CD133 antibody conjugation to decellularized human heart valves intended for circulating cell capture.

    Science.gov (United States)

    Vossler, John D; Min Ju, Young; Williams, J Koudy; Goldstein, Steven; Hamlin, James; Lee, Sang Jin; Yoo, James J; Atala, Anthony

    2015-09-03

    The long term efficacy of tissue based heart valve grafts may be limited by progressive degeneration characterized by immune mediated inflammation and calcification. To avoid this degeneration, decellularized heart valves with functionalized surfaces capable of rapid in vivo endothelialization have been developed. The aim of this study is to examine the capacity of CD133 antibody-conjugated valve tissue to capture circulating endothelial progenitor cells (EPCs). Decellularized human pulmonary valve tissue was conjugated with CD133 antibody at varying concentrations and exposed to CD133 expressing NTERA-2 cl.D1 (NT2) cells in a microflow chamber. The amount of CD133 antibody conjugated on the valve tissue surface and the number of NT2 cells captured in the presence of shear stress was measured. Both the amount of CD133 antibody conjugated to the valve leaflet surface and the number of adherent NT2 cells increased as the concentration of CD133 antibody present in the surface immobilization procedure increased. The data presented in this study support the hypothesis that the rate of CD133(+) cell adhesion in the presence of shear stress to decellularized heart valve tissue functionalized by CD133 antibody conjugation increases as the quantity of CD133 antibody conjugated to the tissue surface increases.

  3. Technetium-99m-ECD SPECT in antiphospholipid antibody syndrome: a drastic improvement in brain perfusion by antiplatelet therapy

    Energy Technology Data Exchange (ETDEWEB)

    Tokumaru, Sunao; Yoshikai, Tomonori; Uchino, Akira; Kudo, Sho [Dept. of Radiology, Saga Medical School (Japan); Matsui, Makoto; Kuroda, Yasuo [Dept. of Neurology, Saga Medical School (Japan)

    2001-12-01

    We present a case of antiphospholipid antibody syndrome (APS) with repeated transient ischemic attacks (TIAs). Magnetic resonance imaging showed multiple cerebral infarcts and ischemic changes in the cerebral white matter. Cerebral angiographies showed no abnormalities. Technetium-99m-ethyl cysteinate dimer (Tc-99m-ECD) brain SPECT showed multiple decreased perfusion areas, which were more extensive than the lesions demonstrated on MRI. After treatment with an antiplatelet agent, the patient subsequently recovered from the TIAs. Although no interval changes were observed by MRI after therapy, follow-up Tc-99m-ECD SPECT revealed a marked improvement in brain perfusion. This is the first imaging report of remarkable post-therapy improvement in brain perfusion in APS cases. (orig.)

  4. Technetium-99m-ECD SPECT in antiphospholipid antibody syndrome: a drastic improvement in brain perfusion by antiplatelet therapy

    International Nuclear Information System (INIS)

    Tokumaru, Sunao; Yoshikai, Tomonori; Uchino, Akira; Kudo, Sho; Matsui, Makoto; Kuroda, Yasuo

    2001-01-01

    We present a case of antiphospholipid antibody syndrome (APS) with repeated transient ischemic attacks (TIAs). Magnetic resonance imaging showed multiple cerebral infarcts and ischemic changes in the cerebral white matter. Cerebral angiographies showed no abnormalities. Technetium-99m-ethyl cysteinate dimer (Tc-99m-ECD) brain SPECT showed multiple decreased perfusion areas, which were more extensive than the lesions demonstrated on MRI. After treatment with an antiplatelet agent, the patient subsequently recovered from the TIAs. Although no interval changes were observed by MRI after therapy, follow-up Tc-99m-ECD SPECT revealed a marked improvement in brain perfusion. This is the first imaging report of remarkable post-therapy improvement in brain perfusion in APS cases. (orig.)

  5. Regional and systemic distribution of anti-tumor x anti-CD3 heteroaggregate antibodies and cultured human peripheral blood lymphocytes in a human colon cancer xenograft

    International Nuclear Information System (INIS)

    Nelson, H.; Ramsey, P.S.; Kerr, L.A.; McKean, D.J.; Donohue, J.H.

    1990-01-01

    Anti-tumor antibody (317G5) covalently coupled to an anti-CD3 antibody (OKT3) produces a heteroaggregate (HA) antibody that can target PBL to lyse tumor cells expressing the appropriate tumor Ag. The i.v. and i.p. distribution of radiolabeled HA antibody 317G5 x OKT3 and of radiolabeled cultured human PBL were studied in athymic nude mice bearing solid intraperitoneal tumor established from the human colon tumor line, LS174T. Mice were injected with 125I-labeled HA antibody, 125I-labeled anti-tumor mAb, or 111In-labeled PBL, and at designated timepoints tissues were harvested and measured for radioactivity. 125I-317G5 x OKT3 localized specifically to tumor sites. Tumor radioactivity levels (percent injected dose/gram) were lower with 125I-317G5 x OKT3 HA antibody than with 125I-317G5 anti-tumor mAb, but were similar to levels reported for other anti-tumor mAb. The major difference in radioactivity levels observed between i.v. and i.p. administration of 125I-317G5 x OKT3 was an increase in hepatic radioactivity after i.v. HA antibody administration. HA antibodies produced from F(ab')2 fragments, which exhibit decreased m. w. and decreased Fc receptor-mediated binding, demonstrated improved tumor:tissue ratios as compared to intact antibody HA. 125I-317G5 F(ab')2 x OKT3 F(ab')2 antibody levels were equivalent to intact HA antibody levels in tumor, but were lower than intact HA antibody levels in the blood, bowel, and liver. Tumor:bowel ratios (20:1 at 48 h) were highest when 317G5 F(ab')2 x OKT3 F(ab')2 was injected i.p. Autoradiography confirmed that anti-tumor x anti-CD3 HA antibodies localized specifically to intraperitoneal tumor; that i.p. administered HA antibodies penetrated tumor directly; and that i.v. administered HA antibodies distributed along tumor vasculature

  6. Human antibody technology and the development of antibodies against cytomegalovirus.

    Science.gov (United States)

    Ohlin, Mats; Söderberg-Nauclér, Cecilia

    2015-10-01

    Cytomegalovirus (CMV) is a virus that causes chronic infections in a large set of the population. It may cause severe disease in immunocompromised individuals, is linked to immunosenescence and implied to play an important role in the pathogenesis of cardiovascular diseases and cancer. Modulation of the immune system's abilities to manage the virus represent a highly viable therapeutic option and passive immunotherapy with polyclonal antibody preparations is already in clinical use. Defined monoclonal antibodies offer many advantages over polyclonal antibodies purified from serum. Human CMV-specific monoclonal antibodies have consequently been thoroughly investigated with respect to their potential in the treatment of diseases caused by CMV. Recent advances in human antibody technology have substantially expanded the breadth of antibodies for such applications. This review summarizes the fundamental basis for treating CMV disease by use of antibodies, the basic technologies to be used to develop such antibodies, and relevant human antibody specificities available to target this virus. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Presence of voltage-gated potassium channel complex antibody in a case of genetic prion disease.

    Science.gov (United States)

    Jammoul, Adham; Lederman, Richard J; Tavee, Jinny; Li, Yuebing

    2014-06-05

    Voltage-gated potassium channel (VGKC) complex antibody-mediated encephalitis is a recently recognised entity which has been reported to mimic the clinical presentation of Creutzfeldt-Jakob disease (CJD). Testing for the presence of this neuronal surface autoantibody in patients presenting with subacute encephalopathy is therefore crucial as it may both revoke the bleak diagnosis of prion disease and allow institution of potentially life-saving immunotherapy. Tempering this optimistic view is the rare instance when a positive VGKC complex antibody titre occurs in a definite case of prion disease. We present a pathologically and genetically confirmed case of CJD with elevated serum VGKC complex antibody titres. This case highlights the importance of interpreting the result of a positive VGKC complex antibody with caution and in the context of the overall clinical manifestation. 2014 BMJ Publishing Group Ltd.

  8. Rapid profiling of the antigen regions recognized by serum antibodies using massively parallel sequencing of antigen-specific libraries.

    KAUST Repository

    Domina, Maria; Lanza Cariccio, Veronica; Benfatto, Salvatore; D'Aliberti, Deborah; Venza, Mario; Borgogni, Erica; Castellino, Flora; Biondo, Carmelo; D'Andrea, Daniel; Grassi, Luigi; Tramontano, Anna; Teti, Giuseppe; Felici, Franco; Beninati, Concetta

    2014-01-01

    There is a need for techniques capable of identifying the antigenic epitopes targeted by polyclonal antibody responses during deliberate or natural immunization. Although successful, traditional phage library screening is laborious and can map only some of the epitopes. To accelerate and improve epitope identification, we have employed massive sequencing of phage-displayed antigen-specific libraries using the Illumina MiSeq platform. This enabled us to precisely identify the regions of a model antigen, the meningococcal NadA virulence factor, targeted by serum antibodies in vaccinated individuals and to rank hundreds of antigenic fragments according to their immunoreactivity. We found that next generation sequencing can significantly empower the analysis of antigen-specific libraries by allowing simultaneous processing of dozens of library/serum combinations in less than two days, including the time required for antibody-mediated library selection. Moreover, compared with traditional plaque picking, the new technology (named Phage-based Representation OF Immuno-Ligand Epitope Repertoire or PROFILER) provides superior resolution in epitope identification. PROFILER seems ideally suited to streamline and guide rational antigen design, adjuvant selection, and quality control of newly produced vaccines. Furthermore, this method is also susceptible to find important applications in other fields covered by traditional quantitative serology.

  9. Rapid profiling of the antigen regions recognized by serum antibodies using massively parallel sequencing of antigen-specific libraries.

    Directory of Open Access Journals (Sweden)

    Maria Domina

    Full Text Available There is a need for techniques capable of identifying the antigenic epitopes targeted by polyclonal antibody responses during deliberate or natural immunization. Although successful, traditional phage library screening is laborious and can map only some of the epitopes. To accelerate and improve epitope identification, we have employed massive sequencing of phage-displayed antigen-specific libraries using the Illumina MiSeq platform. This enabled us to precisely identify the regions of a model antigen, the meningococcal NadA virulence factor, targeted by serum antibodies in vaccinated individuals and to rank hundreds of antigenic fragments according to their immunoreactivity. We found that next generation sequencing can significantly empower the analysis of antigen-specific libraries by allowing simultaneous processing of dozens of library/serum combinations in less than two days, including the time required for antibody-mediated library selection. Moreover, compared with traditional plaque picking, the new technology (named Phage-based Representation OF Immuno-Ligand Epitope Repertoire or PROFILER provides superior resolution in epitope identification. PROFILER seems ideally suited to streamline and guide rational antigen design, adjuvant selection, and quality control of newly produced vaccines. Furthermore, this method is also susceptible to find important applications in other fields covered by traditional quantitative serology.

  10. Rapid profiling of the antigen regions recognized by serum antibodies using massively parallel sequencing of antigen-specific libraries.

    KAUST Repository

    Domina, Maria

    2014-12-04

    There is a need for techniques capable of identifying the antigenic epitopes targeted by polyclonal antibody responses during deliberate or natural immunization. Although successful, traditional phage library screening is laborious and can map only some of the epitopes. To accelerate and improve epitope identification, we have employed massive sequencing of phage-displayed antigen-specific libraries using the Illumina MiSeq platform. This enabled us to precisely identify the regions of a model antigen, the meningococcal NadA virulence factor, targeted by serum antibodies in vaccinated individuals and to rank hundreds of antigenic fragments according to their immunoreactivity. We found that next generation sequencing can significantly empower the analysis of antigen-specific libraries by allowing simultaneous processing of dozens of library/serum combinations in less than two days, including the time required for antibody-mediated library selection. Moreover, compared with traditional plaque picking, the new technology (named Phage-based Representation OF Immuno-Ligand Epitope Repertoire or PROFILER) provides superior resolution in epitope identification. PROFILER seems ideally suited to streamline and guide rational antigen design, adjuvant selection, and quality control of newly produced vaccines. Furthermore, this method is also susceptible to find important applications in other fields covered by traditional quantitative serology.

  11. CD44 antibodies and immune thrombocytopenia in the amelioration of murine inflammatory arthritis.

    Directory of Open Access Journals (Sweden)

    Patrick J Mott

    Full Text Available Antibodies to CD44 have been used to successfully ameliorate murine models of autoimmune disease. The most often studied disease model has been murine inflammatory arthritis, where a clear mechanism for the efficacy of CD44 antibodies has not been established. We have recently shown in a murine passive-model of the autoimmune disease immune thrombocytopenia (ITP that some CD44 antibodies themselves can induce thrombocytopenia in mice, and the CD44 antibody causing the most severe thrombocytopenia (IM7, also is known to be highly effective in ameliorating murine models of arthritis. Recent work in the K/BxN serum-induced model of arthritis demonstrated that antibody-induced thrombocytopenia reduced arthritis, causing us to question whether CD44 antibodies might primarily ameliorate arthritis through their thrombocytopenic effect. We evaluated IM7, IRAWB14.4, 5035-41.1D, KM201, KM114, and KM81, and found that while all could induce thrombocytopenia, the degree of protection against serum-induced arthritis was not closely related to the length or severity of the thrombocytopenia. CD44 antibody treatment was also able to reverse established inflammation, while thrombocytopenia induced by an anti-platelet antibody targeting the GPIIbIIIa platelet antigen, could not mediate this effect. While CD44 antibody-induced thrombocytopenia may contribute to some of its therapeutic effect against the initiation of arthritis, for established disease there are likely other mechanisms contributing to its efficacy. Humans are not known to express CD44 on platelets, and are therefore unlikely to develop thrombocytopenia after CD44 antibody treatment. An understanding of the relationship between arthritis, thrombocytopenia, and CD44 antibody treatment remains critical for continued development of CD44 antibody therapeutics.

  12. Antimitochondrial antibody

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003529.htm Antimitochondrial antibody To use the sharing features on this page, please enable JavaScript. Antimitochondrial antibodies (AMA) are substances ( antibodies ) that form against mitochondria. ...

  13. HIV antibodies for treatment of HIV infection.

    Science.gov (United States)

    Margolis, David M; Koup, Richard A; Ferrari, Guido

    2017-01-01

    The bar is high to improve on current combination antiretroviral therapy (ART), now highly effective, safe, and simple. However, antibodies that bind the HIV envelope are able to uniquely target the virus as it seeks to enter new target cells, or as it is expressed from previously infected cells. Furthermore, the use of antibodies against HIV as a therapeutic may offer advantages. Antibodies can have long half-lives, and are being considered as partners for long-acting antiretrovirals for use in therapy or prevention of HIV infection. Early studies in animal models and in clinical trials suggest that such antibodies can have antiviral activity but, as with small-molecule antiretrovirals, the issues of viral escape and resistance will have to be addressed. Most promising, however, are the unique properties of anti-HIV antibodies: the potential ability to opsonize viral particles, to direct antibody-dependent cellular cytotoxicity (ADCC) against actively infected cells, and ultimately the ability to direct the clearance of HIV-infected cells by effector cells of the immune system. These distinctive activities suggest that HIV antibodies and their derivatives may play an important role in the next frontier of HIV therapeutics, the effort to develop treatments that could lead to an HIV cure. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  14. c-Myb Regulates the T-Bet-Dependent Differentiation Program in B Cells to Coordinate Antibody Responses

    Directory of Open Access Journals (Sweden)

    Dana Piovesan

    2017-04-01

    Full Text Available Summary: Humoral immune responses are tailored to the invading pathogen through regulation of key transcription factors and their networks. This is critical to establishing effective antibody-mediated responses, yet it is unknown how B cells integrate pathogen-induced signals to drive or suppress transcriptional programs specialized for each class of pathogen. Here, we detail the key role of the transcription factor c-Myb in regulating the T-bet-mediated anti-viral program. Deletion of c-Myb in mature B cells significantly increased serum IgG2c and CXCR3 expression by upregulating T-bet, normally suppressed during Th2-cell-mediated responses. Enhanced expression of T-bet resulted in aberrant plasma cell differentiation within the germinal center, mediated by CXCR3 expression. These findings identify a dual role for c-Myb in limiting inappropriate effector responses while coordinating plasma cell differentiation with germinal center egress. Identifying such intrinsic regulators of specialized antibody responses can assist in vaccine design and therapeutic intervention in B-cell-mediated immune disorders. : Piovesan et al. examine how B cells establish transcriptional programs that result in tailored responses to invading pathogens. The authors find that the transcription factor c-Myb represses the T-bet-mediated anti-viral program in B cells. c-Myb limits inappropriate effector responses while coordinating plasma cell differentiation with germinal center egress. Keywords: B cells, c-Myb, T-bet, immunoglobulin, CXCR3, plasma cell, germinal center

  15. Purification of immunoreactive radiolabeled moniclonal antibodies with anti-iodiotypic moniclonal antibodies

    International Nuclear Information System (INIS)

    Temponi, M.; Pupa, S.; Ferrone, S.

    1990-01-01

    A method is described to purify immunoreactive moniclonal antibodies from radiolabeled monoclonal antibody preparations. The method is based on incubation of radiolabeled monoclonal antibodies with insolubilized anti-idiotypic monoclonal antibodies to idiotopes within the antigen-combining site of monoclonal antibodies to be purified an elution of bound monoclonal antibodies with a low pH buffer. The immunoreactive fraction of the purified monoclonal antibodies was at least 82%; the yeald was at least 73%. The purification procedure did not cause any detectable change in the affinity constant of the eluted monoclonal antibodies. The method is simple and rapid; the requirement for anti-idiotypic monoclonal antibodies to idiotopes within the antigen-combining site of the antibodies to be purified is not likely to represent a major limitation in the broad application of the present method, since the hybridoma technology has greatly facilitated the development of anti-idiotypic monoclonal antibodies. (author). 12 refs.; 4 figs.; 1 tab

  16. Anti-Jo-1 antibody-positive patients show a characteristic necrotizing perifascicular myositis.

    Science.gov (United States)

    Mescam-Mancini, Lénaig; Allenbach, Yves; Hervier, Baptiste; Devilliers, Hervé; Mariampillay, Kuberaka; Dubourg, Odile; Maisonobe, Thierry; Gherardi, Romain; Mezin, Paulette; Preusse, Corinna; Stenzel, Werner; Benveniste, Olivier

    2015-09-01

    Idiopathic inflammatory myopathies can be classified as polymyositis, dermatomyositis, immune-mediated necrotizing myopathy, sporadic inclusion body myositis or non-specific myositis. Anti-Jo-1 antibody-positive patients are assigned to either polymyositis or dermatomyositis suggesting overlapping pathological features. We aimed to determine if anti-Jo-1 antibody-positive myopathy has a specific morphological phenotype. In a series of 53 muscle biopsies of anti-Jo-1 antibody-positive patients, relevant descriptive criteria defining a characteristic morphological pattern were identified. They were tested in a second series of anti-Jo-1 antibody-positive patients and compared to 63 biopsies from patients suffering from other idiopathic inflammatory myopathies. In anti-Jo-1 antibody-positive patients, necrotic fibres, which strongly clustered in perifascicular regions, were frequently observed. Sarcolemmal complement deposition was detected specifically in perifascicular areas. Inflammation was mainly located in the perimysium and around vessels in 90.6%. Perimysial fragmentation was observed in 90% of cases. Major histocompatibility complex class I staining was diffusely positive, with a perifascicular reinforcement. Multivariate analysis showed that criteria defining perifascicular pathology: perifascicular necrosis, atrophy, and perimysial fragmentation allow the distinction of anti-Jo-1 antibody-positive patients, among patients suffering from other idiopathic inflammatory myopathies. Anti-Jo-1 antibody-positive patients displayed perifascicular necrosis, whereas dermatomyositis patients exhibited perifascicular atrophy. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Opsonising antibodies to P. falciparum merozoites associated with immunity to clinical malaria.

    Directory of Open Access Journals (Sweden)

    Danika L Hill

    Full Text Available Naturally acquired humoral immunity to the malarial parasite Plasmodium falciparum can protect against disease, although the precise mechanisms remain unclear. Although antibody levels can be measured by ELISA, few studies have investigated functional antibody assays in relation to clinical outcomes. In this study we applied a recently developed functional assay of antibody-mediated opsonisation of merozoites, to plasma samples from a longitudinal cohort study conducted in a malaria endemic region of Papua New Guinea (PNG. Phagocytic activity was quantified by flow cytometry using a standardized and high-throughput protocol, and was subsequently evaluated for association with protection from clinical malaria and high-density parasitemia. Opsonising antibody responses were found to: i increase with age, ii be enhanced by concurrent infection, and iii correlate with protection from clinical episodes and high-density parasitemia. Stronger protective associations were observed in individuals with no detectable parasitemia at baseline. This study presents the first evidence for merozoite phagocytosis as a correlate of acquired immunity and clinical protection against P. falciparum malaria.

  18. Antibody mimetics: promising complementary agents to animal-sourced antibodies.

    Science.gov (United States)

    Baloch, Abdul Rasheed; Baloch, Abdul Wahid; Sutton, Brian J; Zhang, Xiaoying

    2016-01-01

    Despite their wide use as therapeutic, diagnostic and detection agents, the limitations of polyclonal and monoclonal antibodies have inspired scientists to design the next generation biomedical agents, so-called antibody mimetics that offer many advantages over conventional antibodies. Antibody mimetics can be constructed by protein-directed evolution or fusion of complementarity-determining regions through intervening framework regions. Substantial progress in exploiting human, butterfly (Pieris brassicae) and bacterial systems to design and select mimetics using display technologies has been made in the past 10 years, and one of these mimetics [Kalbitor® (Dyax)] has made its way to market. Many challenges lie ahead to develop mimetics for various biomedical applications, especially those for which conventional antibodies are ineffective, and this review describes the current characteristics, construction and applications of antibody mimetics compared to animal-sourced antibodies. The possible limitations of mimetics and future perspectives are also discussed.

  19. The impact of hydroxychloroquine treatment on pregnancy outcome in women with antiphospholipid antibodies.

    Science.gov (United States)

    Sciascia, S; Hunt, B J; Talavera-Garcia, E; Lliso, G; Khamashta, M A; Cuadrado, M J

    2016-02-01

    Antiphospholipid syndrome is defined by the combination of thrombotic events and/or obstetric morbidity in patients who have tested positive persistently for antiphospholipid antibodies. With good treatment, approximately 70% of pregnant women with antiphospholipid syndrome will deliver a viable live infant. However, current management does not prevent all maternal, fetal, and neonatal complications of antiphospholipid syndrome. This observational, retrospective, single-center cohort study aimed to assess pregnancy outcome in women with antiphospholipid antibodies who were treated with hydroxychloroquine in addition to conventional treatment during pregnancy. One-hundred seventy pregnancies in 96 women with persistent antiphospholipid antibodies were analyzed: (1) 51 pregnancies that occurred in 31 women were treated with hydroxychloroquine for at least 6 months before pregnancy, and the therapy continued throughout gestation (group A); (2) 119 pregnancies that occurred in 65 women with antiphospholipid antibodies that were not treated with hydroxychloroquine were included as controls (group B). Hydroxychloroquine-treatment was associated with a higher rate of live births (67% group A vs 57% group B; P = .05) and a lower prevalence of antiphospholipid antibodies-related pregnancy morbidity (47% group A vs 63% B; P = .004). The association of hydroxychloroquine with a lower rate of any complication in pregnancy was confirmed after multivariate analysis (odds ratio, 2.2; 95% confidence interval, 1.2-136; P = .04). Fetal losses at >10 weeks of gestation (2% vs 11%; P = .05) and placenta-mediated complications (2% vs 11%; P = .05) were less frequent in group A than group B. Pregnancy duration was longer in group A than group B (27.6 [6-40] vs 21.5 [6-40] weeks; P = .03). There was a higher rate of spontaneous vaginal labor in hydroxychloroquine-treated women compared with group B (37.3% vs 14.3%; P = .01). Despite the heterogeneity in the 2 groups in terms of systemic

  20. Immunization Elicits Antigen-Specific Antibody Sequestration in Dorsal Root Ganglia Sensory Neurons

    Science.gov (United States)

    Gunasekaran, Manojkumar; Chatterjee, Prodyot K.; Shih, Andrew; Imperato, Gavin H.; Addorisio, Meghan; Kumar, Gopal; Lee, Annette; Graf, John F.; Meyer, Dan; Marino, Michael; Puleo, Christopher; Ashe, Jeffrey; Cox, Maureen A.; Mak, Tak W.; Bouton, Chad; Sherry, Barbara; Diamond, Betty; Andersson, Ulf; Coleman, Thomas R.; Metz, Christine N.; Tracey, Kevin J.; Chavan, Sangeeta S.

    2018-01-01

    The immune and nervous systems are two major organ systems responsible for host defense and memory. Both systems achieve memory and learning that can be retained, retrieved, and utilized for decades. Here, we report the surprising discovery that peripheral sensory neurons of the dorsal root ganglia (DRGs) of immunized mice contain antigen-specific antibodies. Using a combination of rigorous molecular genetic analyses, transgenic mice, and adoptive transfer experiments, we demonstrate that DRGs do not synthesize these antigen-specific antibodies, but rather sequester primarily IgG1 subtype antibodies. As revealed by RNA-seq and targeted quantitative PCR (qPCR), dorsal root ganglion (DRG) sensory neurons harvested from either naïve or immunized mice lack enzymes (i.e., RAG1, RAG2, AID, or UNG) required for generating antibody diversity and, therefore, cannot make antibodies. Additionally, transgenic mice that express a reporter fluorescent protein under the control of Igγ1 constant region fail to express Ighg1 transcripts in DRG sensory neurons. Furthermore, neural sequestration of antibodies occurs in mice rendered deficient in neuronal Rag2, but antibody sequestration is not observed in DRG sensory neurons isolated from mice that lack mature B cells [e.g., Rag1 knock out (KO) or μMT mice]. Finally, adoptive transfer of Rag1-deficient bone marrow (BM) into wild-type (WT) mice or WT BM into Rag1 KO mice revealed that antibody sequestration was observed in DRG sensory neurons of chimeric mice with WT BM but not with Rag1-deficient BM. Together, these results indicate that DRG sensory neurons sequester and retain antigen-specific antibodies released by antibody-secreting plasma cells. Coupling this work with previous studies implicating DRG sensory neurons in regulating antigen trafficking during immunization raises the interesting possibility that the nervous system collaborates with the immune system to regulate antigen-mediated responses. PMID:29755449

  1. Immunization Elicits Antigen-Specific Antibody Sequestration in Dorsal Root Ganglia Sensory Neurons

    Directory of Open Access Journals (Sweden)

    Manojkumar Gunasekaran

    2018-04-01

    Full Text Available The immune and nervous systems are two major organ systems responsible for host defense and memory. Both systems achieve memory and learning that can be retained, retrieved, and utilized for decades. Here, we report the surprising discovery that peripheral sensory neurons of the dorsal root ganglia (DRGs of immunized mice contain antigen-specific antibodies. Using a combination of rigorous molecular genetic analyses, transgenic mice, and adoptive transfer experiments, we demonstrate that DRGs do not synthesize these antigen-specific antibodies, but rather sequester primarily IgG1 subtype antibodies. As revealed by RNA-seq and targeted quantitative PCR (qPCR, dorsal root ganglion (DRG sensory neurons harvested from either naïve or immunized mice lack enzymes (i.e., RAG1, RAG2, AID, or UNG required for generating antibody diversity and, therefore, cannot make antibodies. Additionally, transgenic mice that express a reporter fluorescent protein under the control of Igγ1 constant region fail to express Ighg1 transcripts in DRG sensory neurons. Furthermore, neural sequestration of antibodies occurs in mice rendered deficient in neuronal Rag2, but antibody sequestration is not observed in DRG sensory neurons isolated from mice that lack mature B cells [e.g., Rag1 knock out (KO or μMT mice]. Finally, adoptive transfer of Rag1-deficient bone marrow (BM into wild-type (WT mice or WT BM into Rag1 KO mice revealed that antibody sequestration was observed in DRG sensory neurons of chimeric mice with WT BM but not with Rag1-deficient BM. Together, these results indicate that DRG sensory neurons sequester and retain antigen-specific antibodies released by antibody-secreting plasma cells. Coupling this work with previous studies implicating DRG sensory neurons in regulating antigen trafficking during immunization raises the interesting possibility that the nervous system collaborates with the immune system to regulate antigen-mediated responses.

  2. Fc receptors for mouse IgG1 on human monocytes: polymorphism and role in antibody-induced T cell proliferation.

    Science.gov (United States)

    Tax, W J; Hermes, F F; Willems, R W; Capel, P J; Koene, R A

    1984-09-01

    In previous studies, it was shown that there is polymorphism in the mitogenic effect of mouse IgG1 monoclonal antibodies against the T3 antigen of human T cells. This polymorphism implies that IgG1 anti-T3 antibodies are not mitogenic for T cells from 30% of healthy individuals. The present results demonstrate that this polymorphism is caused by polymorphism of an Fc receptor for mouse IgG1, present on human monocytes. The Fc receptor for murine IgG1 could be detected by a newly developed rosetting assay on monocytes from all individuals responsive to the mitogenic effect of IgG1 anti-T3 antibodies. This Fc receptor was not detectable on monocytes from those individuals exhibiting no mitogenic responses to IgG1 anti-T3 monoclonal antibodies. Cross-linking of T3 antigens appears to be essential for antibody-induced mitosis of T cells, because mononuclear cells that did not proliferate in response to WT 31 (an IgG1 antibody against T3 antigen) showed a proliferative response to Sepharose beads coated with WT 31. The Fc receptor--if functionally present--may be involved in the cross-linking of T3 antigens through anti-T3 antibodies. Further evidence for the involvement of this Fc receptor in antibody-induced T cell proliferation was provided by inhibition studies. Immune complexes containing IgG1 antibodies were able to inhibit the proliferative response to IgG1 anti-T3 antibodies. This inhibition by immune complexes appears to be mediated through the monocyte Fc receptor for mouse IgG1. These findings are important for the interpretation of previously described inhibitory effects of anti-T cell monoclonal antibodies on T cell proliferation, and show that such inhibitory effects may be monocyte-mediated (via immune complexes) rather than caused by a direct involvement of the respective T cell antigens in T cell mitosis. The Fc receptor for mouse IgG1 plays a role in antibody-induced T cell proliferation. Its polymorphism may have important implications for the

  3. Implications of Antiphospholipid and Antineutrophilic Cytoplasmic Antibodies in the Context of Postinfectious Glomerulonephritis

    Directory of Open Access Journals (Sweden)

    Daniel Leifer

    2017-01-01

    Full Text Available While antineutrophil cytoplasmic antibody (ANCA positivity has been documented in some patients with postinfectious glomerulonephritis (PIGN and is associated with more severe disease, antiphospholipid antibodies (APA are not known to be a common occurrence. We describe a child with severe acute kidney injury who was noted to have prolonged positivity of both ANCA and APA; a renal biopsy showed noncrescentic immune complex mediated glomerulonephritis with subepithelial deposits compatible with PIGN. He recovered without maintenance immunosuppressive therapy and at last follow-up had normal renal function. We discuss the cooccurrence and implications of ANCA and APA in children with PIGN.

  4. Fv-clasp: An Artificially Designed Small Antibody Fragment with Improved Production Compatibility, Stability, and Crystallizability.

    Science.gov (United States)

    Arimori, Takao; Kitago, Yu; Umitsu, Masataka; Fujii, Yuki; Asaki, Ryoko; Tamura-Kawakami, Keiko; Takagi, Junichi

    2017-10-03

    Antibody fragments are frequently used as a "crystallization chaperone" to aid structural analysis of complex macromolecules that are otherwise crystallization resistant, but conventional fragment formats have not been designed for this particular application. By fusing an anti-parallel coiled-coil structure derived from the SARAH domain of human Mst1 kinase to the variable region of an antibody, we succeeded in creating a novel chimeric antibody fragment of ∼37 kDa, termed "Fv-clasp," which exhibits excellent crystallization compatibility while maintaining the binding ability of the original IgG molecule. The "clasp" and the engineered disulfide bond at the bottom of the Fv suppressed the internal mobility of the fragment and shielded hydrophobic residues, likely contributing to the high heat stability and the crystallizability of the Fv-clasp. Finally, Fv-clasp antibodies showed superior "chaperoning" activity over conventional Fab fragments, and facilitated the structure determination of an ectodomain fragment of integrin α6β1. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. π-Clamp-mediated cysteine conjugation

    Science.gov (United States)

    Zhang, Chi; Welborn, Matthew; Zhu, Tianyu; Yang, Nicole J.; Santos, Michael S.; van Voorhis, Troy; Pentelute, Bradley L.

    2016-02-01

    Site-selective functionalization of complex molecules is one of the most significant challenges in chemistry. Typically, protecting groups or catalysts must be used to enable the selective modification of one site among many that are similarly reactive, and general strategies that selectively tune the local chemical environment around a target site are rare. Here, we show a four-amino-acid sequence (Phe-Cys-Pro-Phe), which we call the ‘π-clamp’, that tunes the reactivity of its cysteine thiol for site-selective conjugation with perfluoroaromatic reagents. We use the π-clamp to selectively modify one cysteine site in proteins containing multiple endogenous cysteine residues. These examples include antibodies and cysteine-based enzymes that would be difficult to modify selectively using standard cysteine-based methods. Antibodies modified using the π-clamp retained binding affinity to their targets, enabling the synthesis of site-specific antibody-drug conjugates for selective killing of HER2-positive breast cancer cells. The π-clamp is an unexpected approach to mediate site-selective chemistry and provides new avenues to modify biomolecules for research and therapeutics.

  6. Elucidation of Distinct Roles of Guinea Pig CXCR1 and CXCR2 in Neutrophil Migration toward IL-8 and GROα by Specific Antibodies.

    Science.gov (United States)

    Tanaka, Kento; Yoshitomi, Tomomi; Hirahara, Kazuki

    2017-01-01

    Chemokine receptors CXCR1 and CXCR2 are conserved between guinea pigs and humans, but the distinct role of each receptor in chemotactic responses of neutrophils against chemokine ligands has not been elucidated due in part to the lack of specific inhibitors against these receptors in guinea pigs. In this study, we investigated the roles of guinea pig CXCR1 and CXCR2 on neutrophils in chemotactic responses to guinea pig interleukin (IL)-8 and growth-regulated oncogene (GRO)α by using specific inhibitory antibodies against these receptors. Neutrophil migration induced by IL-8 was partially inhibited by either anti-CXCR1 antibody or anti-CXCR2 antibody. In addition, the migration was inhibited completely when both anti-CXCR1 and anti-CXCR2 antibodies were combined. On the other hand, neutrophil migration induced by GROα was not inhibited by anti-CXCR1 antibody while inhibited profoundly by anti-CXCR2 antibody. These results indicated that CXCR1 and CXCR2 mediated migration induced by the IL-8 synergistically and only CXCR2 mediated migration induced by GROα in guinea pig neutrophils. Our findings on ligand selectivity of CXCR1 and CXCR2 in guinea pigs are consistent with those in humans.

  7. CD4 T cell-mediated protection from lethal influenza: perforin and antibody-mediated mechanisms give a one-two punch.

    Science.gov (United States)

    Brown, Deborah M; Dilzer, Allison M; Meents, Dana L; Swain, Susan L

    2006-09-01

    The mechanisms whereby CD4 T cells contribute to the protective response against lethal influenza infection remain poorly characterized. To define the role of CD4 cells in protection against a highly pathogenic strain of influenza, virus-specific TCR transgenic CD4 effectors were generated in vitro and transferred into mice given lethal influenza infection. Primed CD4 effectors conferred protection against lethal infection over a broad range of viral dose. The protection mediated by CD4 effectors did not require IFN-gamma or host T cells, but did result in increased anti-influenza Ab titers compared with untreated controls. Further studies indicated that CD4-mediated protection at high doses of influenza required B cells, and that passive transfer of anti-influenza immune serum was therapeutic in B cell-deficient mice, but only when CD4 effectors were present. Primed CD4 cells also acquired perforin (Pfn)-mediated cytolytic activity during effector generation, suggesting a second mechanism used by CD4 cells to confer protection. Pfn-deficient CD4 effectors were less able to promote survival in intact BALB/c mice and were unable to provide protection in B cell-deficient mice, indicating that Ab-independent protection by CD4 effectors requires Pfn. Therefore, CD4 effectors mediate protection to lethal influenza through at least two mechanisms: Pfn-mediated cytotoxicity early in the response promoted survival independently of Ab production, whereas CD4-driven B cell responses resulted in high titer Abs that neutralized remaining virus.

  8. Mediators of improved child diet quality following a health promotion intervention: the Melbourne InFANT Program.

    Science.gov (United States)

    Spence, Alison C; Campbell, Karen J; Crawford, David A; McNaughton, Sarah A; Hesketh, Kylie D

    2014-11-04

    Young children's diets are currently suboptimal. Given that mothers have a critical influence on children' diets, they are typically a target of interventions to improve early childhood nutrition. Understanding the maternal factors which mediate an intervention's effect on young children's diets is important, but has not been well investigated. This research aimed to test whether maternal feeding knowledge, maternal feeding practices, maternal self-efficacy, and maternal dietary intakes acted as mediators of the effect of an intervention to improve child diet quality. The Melbourne Infant Feeding Activity and Nutrition Trial (InFANT) Program was a cluster-randomized controlled trial, conducted from 2008-2010. This novel, low-dose, health promotion intervention was delivered quarterly over 15 months and involved educational activities, promotion of peer discussion, a DVD and written materials. Post-intervention, when children were approximately 18 months of age, child diets were assessed using multiple 24-hour recalls and a purpose-developed index of diet quality, the Obesity Protective Dietary Index. Maternal mediators were assessed using a combination of previously validated and purpose-deigned tools. Mediation analysis was conducted using the test of joint significance and difference of coefficients methods. Across 62 parents' groups in Melbourne, Australia, 542 parents were recruited. Post- intervention, higher maternal feeding knowledge and lower use of foods as rewards was found to mediate the direct intervention effect on child diet quality. While other aspects of maternal feeding practices, self-efficacy and dietary intakes did not act as mediators, they were associated with child diet quality. Mediation analysis of this novel health promotion intervention showed the importance of maternal feeding knowledge and use of foods as rewards in impacting child diet quality. The other maternal factors assessed were appropriate targets but further research on how to

  9. Immobilization of antibodies and enzyme-labeled antibodies by radiation polymerization

    International Nuclear Information System (INIS)

    Kumakura, M.; Kaetsu, I.; Suzuki, M.; Adachi, S.

    1983-01-01

    Immobilization of antibodies and enzyme-labeled antibodies by radiation polymerization at low temperatures was studied. The antibody activity of antibody was not affected by irradiation at an irradiation dose of below 8 MR and low temperatures. Immobilization of peroxidase-labeled anti-rabbit IgG goat IgG, anti-peroxidase, peroxidase, and anti-alpha-fetoprotein was carried out with hydrophilic and hydrophobic monomers. The activity of the immobilized enzyme-labeled antibody membranes varied with the thickness of the membranes and increased with decreasing membrane thickness. The activity of the immobilized antibody particles was varied by particle size. Immobilized anti-alpha-fetoprotein particles and membranes can be used for the assay of alpha-fetoprotein by the antigen-antibody reaction, such as a solid-phase sandwich method with high sensitivity

  10. [VGKC-complex antibodies].

    Science.gov (United States)

    Watanabe, Osamu

    2013-04-01

    Various antibodies are associated with voltage-gated potassium channels (VGKCs). Representative antibodies to VGKCs were first identified by radioimmunoassays using radioisotope-labeled alpha-dendrotoxin-VGKCs solubilized from rabbit brain. These antibodies were detected only in a proportion of patients with acquired neuromyotonia (Isaacs' syndrome). VGKC antibodies were also detected in patients with Morvan's syndrome and in those with a form of autoimmune limbic encephalitis. Recent studies indicated that the "VGKC" antibodies are mainly directed toward associated proteins (for example LGI-1 and CASPR-2) that complex with the VGKCs themselves. The "VGKC" antibodies are now commonly known as VGKC-complex antibodies. In general, LGI-1 antibodies are most commonly detected in patients with limbic encephalitis with syndrome of inappropriate secretion of antidiuretic hormone. CASPR-2 antibodies are present in the majority of patients with Morvan's syndrome. These patients develop combinations of CNS symptoms, autonomic dysfunction, and peripheral nerve hyperexcitability. Furthermore, VGKC-complex antibodies are tightly associated with chronic idiopathic pain. Hyperexcitability of nociceptive pathways has also been implicated. These antibodies may be detected in sera of some patients with neurodegenerative diseases (for example, amyotrophic lateral sclerosis and Creutzfeldt-Jakob disease).

  11. Effect of producer cell line on functional activity of anti-D monoclonal antibodies destined for prevention of rhesus sensitization.

    Science.gov (United States)

    Olovnikova, N I; Ershler, M A; Belkina, E V; Nikolaeva, T L; Miterev, G Yu

    2009-04-01

    The ability of anti-D antibodies to cause antigen-specific immunosuppression depends on their interaction with low-affinity Fcgamma-receptors. Human monoclonal antibodies to D antigen of the rhesus system were investigated by antibody-dependent cytotoxicity assay in order to estimate their ability to induce hemolysis mediated by low-affinity Fcgamma receptors. We demonstrate that affinity of monoclonal antibodies to receptors of this type does not depend on primary structure of Fc-fragment, but depends on the producer cell line which expresses the antibodies. Monoclonal IgG1 antibodies interacting with FcgammaRIIa and FcgammaRIII lost this property, if they were secreted by human-mouse heterohybridoma, but not by human B-cell line. On the opposite, monoclonal antibodies that could not activate low-affinity Fcgamma receptors were highly active after human cells fusion with rat myeloma YB2/0. Hemolytic activity of IgG3 remained unchanged after fusion of human cells with rodent cells.

  12. Leiomyoma-derived transforming growth factor-β impairs bone morphogenetic protein-2-mediated endometrial receptivity.

    Science.gov (United States)

    Doherty, Leo F; Taylor, Hugh S

    2015-03-01

    To determine whether transforming growth factor (TGF)-β3 is a paracrine signal secreted by leiomyoma that inhibits bone morphogenetic protein (BMP)-mediated endometrial receptivity and decidualization. Experimental. Laboratory. Women with symptomatic leiomyomas. Endometrial stromal cells (ESCs) and leiomyoma cells were isolated from surgical specimens. Leiomyoma-conditioned media (LCM) was applied to cultured ESC. The TGF-β was blocked by two approaches: TGF-β pan-specific antibody or transfection with a mutant TGF-β receptor type II. Cells were then treated with recombinant human BMP-2 to assess BMP responsiveness. Expression of BMP receptor types 1A, 1B, 2, as well as endometrial receptivity mediators HOXA10 and leukemia inhibitory factor (LIF). Enzyme-linked immunosorbent assay showed elevated TGF-β levels in LCM. LCM treatment of ESC reduced expression of BMP receptor types 1B and 2 to approximately 60% of pretreatment levels. Preincubation of LCM with TGF-β neutralizing antibody or mutant TGF receptor, but not respective controls, prevented repression of BMP receptors. HOXA10 and LIF expression was repressed in recombinant human BMP-2 treated, LCM exposed ESC. Pretreatment of LCM with TGF-β antibody or transfection with mutant TGF receptor prevented HOXA10 and LIF repression. Leiomyoma-derived TGF-β was necessary and sufficient to alter endometrial BMP-2 responsiveness. Blockade of TGF-β prevents repression of BMP-2 receptors and restores BMP-2-stimulated expression of HOXA10 and LIF. Blockade of TGF signaling is a potential strategy to improve infertility and pregnancy loss associated with uterine leiomyoma. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  13. Alkylation of histidine residues of Bothrops jararacussu venom proteins and isolated phospholipases A2: a biotechnological tool to improve the production of antibodies.

    Science.gov (United States)

    Guimarães, C L S; Andrião-Escarso, S H; Moreira-Dill, L S; Carvalho, B M A; Marchi-Salvador, D P; Santos-Filho, N A; Fernandes, C A H; Fontes, M R M; Giglio, J R; Barraviera, B; Zuliani, J P; Fernandes, C F C; Calderón, L A; Stábeli, R G; Albericio, F; da Silva, S L; Soares, A M

    2014-01-01

    Crude venom of Bothrops jararacussu and isolated phospholipases A2 (PLA2) of this toxin (BthTX-I and BthTX-II) were chemically modified (alkylation) by p-bromophenacyl bromide (BPB) in order to study antibody production capacity in function of the structure-function relationship of these substances (crude venom and PLA2 native and alkylated). BthTX-II showed enzymatic activity, while BthTX-I did not. Alkylation reduced BthTX-II activity by 50% while this process abolished the catalytic and myotoxic activities of BthTX-I, while reducing its edema-inducing activity by about 50%. Antibody production against the native and alkylated forms of BthTX-I and -II and the cross-reactivity of antibodies to native and alkylated toxins did not show any apparent differences and these observations were reinforced by surface plasmon resonance (SPR) data. Histopathological analysis of mouse gastrocnemius muscle sections after injection of PBS, BthTX-I, BthTX-II, or both myotoxins previously incubated with neutralizing antibody showed inhibition of the toxin-induced myotoxicity. These results reveal that the chemical modification of the phospholipases A2 (PLA2) diminished their toxicity but did not alter their antigenicity. This observation indicates that the modified PLA2 may provide a biotechnological tool to attenuate the toxicity of the crude venom, by improving the production of antibodies and decreasing the local toxic effects of this poisonous substance in animals used to produce antivenom.

  14. Simultaneous measurements of auto-immune and infectious disease specific antibodies using a high throughput multiplexing tool.

    Directory of Open Access Journals (Sweden)

    Atul Asati

    Full Text Available Considering importance of ganglioside antibodies as biomarkers in various immune-mediated neuropathies and neurological disorders, we developed a high throughput multiplexing tool for the assessment of gangliosides-specific antibodies based on Biolpex/Luminex platform. In this report, we demonstrate that the ganglioside high throughput multiplexing tool is robust, highly specific and demonstrating ∼100-fold higher concentration sensitivity for IgG detection than ELISA. In addition to the ganglioside-coated array, the high throughput multiplexing tool contains beads coated with influenza hemagglutinins derived from H1N1 A/Brisbane/59/07 and H1N1 A/California/07/09 strains. Influenza beads provided an added advantage of simultaneous detection of ganglioside- and influenza-specific antibodies, a capacity important for the assay of both infectious antigen-specific and autoimmune antibodies following vaccination or disease. Taken together, these results support the potential adoption of the ganglioside high throughput multiplexing tool for measuring ganglioside antibodies in various neuropathic and neurological disorders.

  15. In Vivo Neutralization of α-Cobratoxin with High-Affinity Llama Single-Domain Antibodies (VHHs) and a VHH-Fc Antibody

    Science.gov (United States)

    Richard, Gabrielle; Meyers, Ashley J.; McLean, Michael D.; Arbabi-Ghahroudi, Mehdi; MacKenzie, Roger; Hall, J. Christopher

    2013-01-01

    Small recombinant antibody fragments (e.g. scFvs and VHHs), which are highly tissue permeable, are being investigated for antivenom production as conventional antivenoms consisting of IgG or F(ab’)2 antibody fragments do not effectively neutralize venom toxins located in deep tissues. However, antivenoms composed entirely of small antibody fragments may have poor therapeutic efficacy due to their short serum half-lives. To increase serum persistence and maintain tissue penetration, we prepared low and high molecular mass antivenom antibodies. Four llama VHHs were isolated from an immune VHH-displayed phage library and were shown to have high affinity, in the low nM range, for α-cobratoxin (α–Cbtx), the most lethal component of Naja kaouthia venom. Subsequently, our highest affinity VHH (C2) was fused to a human Fc fragment to create a VHH2-Fc antibody that would offer prolonged serum persistence. After in planta (Nicotiana benthamiana) expression and purification, we show that our VHH2-Fc antibody retained high affinity binding to α–Cbtx. Mouse α–Cbtx challenge studies showed that our highest affinity VHHs (C2 and C20) and the VHH2-Fc antibody effectively neutralized lethality induced by α–Cbtx at an antibody:toxin molar ratio as low as ca. 0.75×:1. Further research towards the development of an antivenom therapeutic involving these anti-α-Cbtx VHHs and VHH2-Fc antibody molecules should involve testing them as a combination, to determine whether they maintain tissue penetration capability and low immunogenicity, and whether they exhibit improved serum persistence and therapeutic efficacy. PMID:23894495

  16. Compositions, antibodies, asthma diagnosis methods, and methods for preparing antibodies

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hongjun; Zangar, Richard C.

    2017-01-17

    Methods for preparing an antibody are provided with the method including incorporating 3-bromo-4-hydroxy-benzoic acid into a protein to form an antigen, immunizing a mammalian host with the antigen, and recovering an antibody having an affinity for the antigen from the host. Antibodies having a binding affinity for a monohalotyrosine are provided as well as composition comprising an antibody bound with monohalotyrosine. Compositions comprising a protein having a 3-bromo-4-hydroxy-benzoic acid moiety are also provided. Methods for evaluating the severity of asthma are provide with the methods including analyzing sputum of a patient using an antibody having a binding affinity for monohalotyrosine, and measuring the amount of antibody bound to protein. Methods for determining eosinophil activity in bodily fluid are also provided with the methods including exposing bodily fluid to an antibody having a binding affinity for monohalotyrosine, and measuring the amount of bound antibody to determine the eosinophil activity.

  17. Acute Antibody-Mediated Rejection in Presence of MICA-DSA and Successful Renal Re-Transplant with Negative-MICA Virtual Crossmatch.

    Directory of Open Access Journals (Sweden)

    Yingzi Ming

    Full Text Available The presence of donor-specific alloantibodies (DSAs against the MICA antigen results in high risk for antibody-mediated rejection (AMR of a transplanted kidney, especially in patients receiving a re-transplant. We describe the incidence of acute C4d+ AMR in a patient who had received a first kidney transplant with a zero HLA antigen mismatch. Retrospective analysis of post-transplant T and B cell crossmatches were negative, but a high level of MICA alloantibody was detected in sera collected both before and after transplant. The DSA against the first allograft mismatched MICA*018 was in the recipient. Flow cytometry and cytotoxicity tests with five samples of freshly isolated human umbilical vein endothelial cells demonstrated the alloantibody nature of patient's MICA-DSA. Prior to the second transplant, a MICA virtual crossmatch and T and B cell crossmatches were used to identify a suitable donor. The patient received a second kidney transplant, and allograft was functioning well at one-year follow-up. Our study indicates that MICA virtual crossmatch is important in selection of a kidney donor if the recipient has been sensitized with MICA antigens.

  18. HYDROXYCHLOROQUINE REDUCES BINDING OF ANTIPHOSPHOLIPID ANTIBODIES TO SYNCYTIOTROPHOBLASTS AND RESTORES ANNEXIN A5 EXPRESSION

    Science.gov (United States)

    Wu, Xiao-Xuan; Guller, Seth; Rand, Jacob H.

    2011-01-01

    Objectives Antibody-mediated disruption of the annexin A5 (AnxA5) anticoagulant shield has been posited to be a thrombogenic mechanism in the antiphospholipid syndrome. We recently showed that the antimalarial drug, hydroxychloroquine, dissociates antiphospholipid immune complexes and restores AnxA5 binding to planar phospholipid bilayer. Using quantitative immunoassays, we demonstrated similar effects on BeWo trophoblasts. We therefore investigated the effects of the drug on localization of AnxA5 in primary cultures of human placental syncytiotrophoblasts (SCTs). Study Laser confocal microscopy with computer-based morphometric analysis was used to localize AnxA5 and antiphospholipid antibodies on SCTs exposed to polyclonal and monoclonal antiphospholipid and control IgGs. Results Hydroxychloroquine reversed the effects of the antiphospholipid antibodies on the SCTs by markedly reducing IgG binding and restoring AnxA5 expression. Conclusions These results provide the first morphologic evidence for this effect of hydroxychloroquine on human placental SCTs and support the possibility of novel treatments that target antiphospholipid antibody binding. PMID:21871597

  19. Antibody Engineering and Therapeutics

    Science.gov (United States)

    Almagro, Juan Carlos; Gilliland, Gary L; Breden, Felix; Scott, Jamie K; Sok, Devin; Pauthner, Matthias; Reichert, Janice M; Helguera, Gustavo; Andrabi, Raiees; Mabry, Robert; Bléry, Mathieu; Voss, James E; Laurén, Juha; Abuqayyas, Lubna; Barghorn, Stefan; Ben-Jacob, Eshel; Crowe, James E; Huston, James S; Johnston, Stephen Albert; Krauland, Eric; Lund-Johansen, Fridtjof; Marasco, Wayne A; Parren, Paul WHI; Xu, Kai Y

    2014-01-01

    The 24th Antibody Engineering & Therapeutics meeting brought together a broad range of participants who were updated on the latest advances in antibody research and development. Organized by IBC Life Sciences, the gathering is the annual meeting of The Antibody Society, which serves as the scientific sponsor. Preconference workshops on 3D modeling and delineation of clonal lineages were featured, and the conference included sessions on a wide variety of topics relevant to researchers, including systems biology; antibody deep sequencing and repertoires; the effects of antibody gene variation and usage on antibody response; directed evolution; knowledge-based design; antibodies in a complex environment; polyreactive antibodies and polyspecificity; the interface between antibody therapy and cellular immunity in cancer; antibodies in cardiometabolic medicine; antibody pharmacokinetics, distribution and off-target toxicity; optimizing antibody formats for immunotherapy; polyclonals, oligoclonals and bispecifics; antibody discovery platforms; and antibody-drug conjugates. PMID:24589717

  20. Pentavalent single-domain antibodies reduce Campylobacter jejuni motility and colonization in chickens.

    Directory of Open Access Journals (Sweden)

    Ali Riazi

    Full Text Available Campylobacter jejuni is the leading cause of bacterial foodborne illness in the world, with symptoms ranging from acute diarrhea to severe neurological disorders. Contaminated poultry meat is a major source of C. jejuni infection, and therefore, strategies to reduce this organism in poultry, are expected to reduce the incidence of Campylobacter-associated diseases. We have investigated whether oral administration of C. jejuni-specific single-domain antibodies would reduce bacterial colonization levels in chickens. Llama single-domain antibodies specific for C. jejuni were isolated from a phage display library generated from the heavy chain IgG variable domain repertoire of a llama immunized with C. jejuni flagella. Two flagella-specific single-domain antibodies were pentamerized to yield high avidity antibodies capable of multivalent binding to the target antigen. When administered orally to C. jejuni-infected two-day old chicks, the pentabodies significantly reduced C. jejuni colonization in the ceca. In vitro, the motility of the bacteria was also reduced in the presence of the flagella-specific pentabodies, suggesting the mechanism of action is through either direct interference with flagellar motility or antibody-mediated aggregation. Fluorescent microscopy and Western blot analyses revealed specific binding of the anti-flagella pentabodies to the C. jejuni flagellin.

  1. Prediction of antibody persistency from antibody titres to natalizumab

    DEFF Research Database (Denmark)

    Jensen, Poul Erik H; Koch-Henriksen, Nils; Sellebjerg, Finn

    2012-01-01

    In a subgroup of patients with multiple sclerosis natalizumab therapy causes generation of anti-natalizumab antibodies that may be transient or persistent. It is recommended to discontinue natalizumab therapy in persistently antibody-positive patients.......In a subgroup of patients with multiple sclerosis natalizumab therapy causes generation of anti-natalizumab antibodies that may be transient or persistent. It is recommended to discontinue natalizumab therapy in persistently antibody-positive patients....

  2. A new application of scanning electrochemical microscopy for the label-free interrogation of antibody-antigen interactions

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, Joanne L.; Davis, Frank; Collyer, Stuart D. [Cranfield Health, Cranfield University, Cranfield, MK43 0AL (United Kingdom); Higson, Seamus P.J., E-mail: s.p.j.higson@cranfield.ac.uk [Cranfield Health, Cranfield University, Cranfield, MK43 0AL (United Kingdom)

    2011-03-18

    Within this work we present a 'proof of principle' study for the use of scanning electrochemical microscopy (SECM) to detect and image biomolecular interactions in a label-free assay as a potential alternative to current fluorescence techniques. Screen-printed carbon electrodes were used as the substrate for the deposition of a dotted array, where the dots consist of biotinylated polyethyleneimine. These were then further derivatised, first with neutravidin and then with a biotinylated antibody to the protein neuron specific enolase (NSE). SECM using a ferrocene carboxylic acid mediator showed clear differences between the array and the surrounding unmodified carbon. Imaging of the arrays before and following exposure to various concentrations of the antigen showed clear evidence for specific binding of the NSE antigen to the antibody derivatised dots. Non-specific binding was quantified. Control experiments with other proteins showed only non-specific binding across the whole of the substrate, thereby confirming that specific binding does occur between the antibody and antigen at the surface of the dots. Binding of the antigen was accompanied by a measured increase in current response, which may be explained in terms of protein electrostatic interaction and hydrophobic interactions to the mediator, thereby increasing the localised mediator flux. A calibration curve was obtained between 500 fg mL{sup -1} to 200 pg mL{sup -1} NSE which demonstrated a logarithmic relationship between the current change upon binding and antigen concentration without the need for any labelling of the substrate.

  3. Tumor-specific detection of an optically targeted antibody combined with a quencher-conjugated neutravidin "quencher-chaser": a dual "quench and chase" strategy to improve target to nontarget ratios for molecular imaging of cancer.

    Science.gov (United States)

    Ogawa, Mikako; Kosaka, Nobuyuki; Choyke, Peter L; Kobayashi, Hisataka

    2009-01-01

    In vivo molecular cancer imaging with monoclonal antibodies has great potential not only for cancer detection, but also for cancer characterization. However, the prolonged retention of intravenously injected antibody in the blood causes low target tumor-to-background ratio (TBR). Avidin has been used as a "chase" to clear the unbound, circulating biotinylated antibody and decrease the background signal. Here, we utilize a combined approach of a fluorescence resonance energy transfer (FRET) quenched antibody with an "avidin chase" to increase TBR. Trastuzumab, a humanized monoclonal antibody against human epidermal growth factor receptor type 2 (HER2), was biotinylated and conjugated with the near-infrared (NIR) fluorophore Alexa680 to synthesize Tra-Alexa680-biotin. Next, the FRET quencher, QSY-21, was conjugated to avidin, neutravidin (nAv), or streptavidin (sAv), thus creating Av-QSY21, nAv-QSY21, or sAv-QSY21 as "chasers". The fluorescence was quenched in vitro by binding Tra-Alexa680-biotin to Av-QSY21, nAv-QSY21, or sAv-QSY21. To evaluate if the injection of quencher-conjugated avidin derivatives can improve target TBR by using a dual "quench and chase" strategy, both target (3T3/HER2+) and nontarget (Balb3T3/ZsGreen) tumor-bearing mice were employed. The "FRET quench" effect induced by all the QSY21 avidin-based conjugates reduced but did not totally eliminate background signal from the blood pool. The addition of nAv-QSY21 administration increased target TBR mainly because of the "chase" effect where unbound conjugated antibody was preferentially cleared to the liver. The relatively slow clearance of unbound nAv-QSY21 leads to further reductions in background signal by leaking out of the vascular space and binding to unbound antibodies in the extravascular space of tumors, resulting in decreased nontarget tumor-to-background ratios but increased target TBR due to the "FRET quench" effect, because target-bound antibodies were internalized and could not bind

  4. Antibody- and TRIM21-dependent intracellular restriction of Salmonella enterica.

    Science.gov (United States)

    Rakebrandt, Nikolas; Lentes, Sabine; Neumann, Heinz; James, Leo C; Neumann-Staubitz, Petra

    2014-11-01

    TRIM21 ('tripartite motif-containing protein 21', Ro52) is a ubiquitously expressed cytosolic Fc receptor, which has a potent role in protective immunity against nonenveloped viruses. TRIM21 mediates intracellular neutralisation of antibody-coated viruses, a process called ADIN (antibody-dependent intracellular neutralisation). Our results reveal a similar mechanism to fight bacterial infections. TRIM21 is recruited to the intracellular pathogen Salmonella enterica in epithelial cells early in infection. TRIM21 does not bind directly to S. enterica, but to antibodies opsonising it. Most importantly, bacterial restriction is dependent on TRIM21 as well as on the opsonisation state of the bacteria. Finally, Salmonella and TRIM21 colocalise with the autophagosomal marker LC3, and intracellular defence is enhanced in starved cells suggesting an involvement of the autophagocytic pathway. Our data extend the protective role of TRIM21 from viruses to bacteria and thereby strengthening the general role of ADIN in cellular immunity. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  5. Job-demand for learning and job-related learning: the mediating effect of job performance improvement initiatives

    OpenAIRE

    Loon, M; Bartram, T

    2007-01-01

    This study examined whether job-performance-improvementinitiatives mediate the relationship between individuals’ job-demand for learning and job-related learning. Data were obtained from 115 full-time\\ud employees in a diverse range of occupations. A partial least squares analysis revealed that job-performance-improvement-initiatives mediate partially the effects of job-demand for learning on job-related learning. Several implications\\ud for future research and policy are drawn from the findi...

  6. HLA class I antibodies trigger increased adherence of monocytes to endothelial cells by eliciting an increase in endothelial P-selectin and, depending on subclass, by engaging FcγRs1

    Science.gov (United States)

    Valenzuela, Nicole M; Mulder, Arend; Reed, Elaine F

    2013-01-01

    Antibody-mediated rejection of solid organ transplants is characterized by intragraft macrophages. It is incompletely understood how donor specific antibody binding to graft endothelium promotes monocyte adhesion, and what, if any, contribution is made by the Fc region of the antibody. We investigated the mechanisms underlying monocyte recruitment by HLA class I antibody-activated endothelium. We used a panel of murine monoclonal antibodies of different subclasses to crosslink HLA I on human aortic, venous and microvascular endothelial cells, and measured the binding of human monocytic cell lines and peripheral blood monocytes. Both anti-HLA I murine IgG1 and mIgG2a induced endothelial P-selectin, which was required for monocyte adhesion to endothelium irrespective of subclass. Mouse IgG2a but not mIgG1 could bind human FcγRs. Accordingly, HLA I mIgG2a but not mIgG1 treatment of endothelial cells significantly augmented recruitment, predominantly through FcγRI, and, to a lesser extent, FcγRIIa. Moreover, HLA I mIgG2a promoted firm adhesion of monocytes to ICAM-1 through Mac-1, which may explain the prominence of monocytes during antibody mediated rejection. We confirmed these observations using human HLA allele specific monoclonal antibodies and IgG purified from transplant patient sera. HLA I antibodies universally elicit endothelial exocytosis leading to monocyte adherence, implying that P-selectin is a putative therapeutic target to prevent macrophage infiltration during antibody-mediated rejection. Importantly, the subclass of donor specific antibody may influence its pathogenesis. These results imply that hIgG1 and hIgG3 should have a greater capacity to trigger monocyte infiltration into the graft than IgG2 or IgG4 due to enhancement by FcγR interactions. PMID:23690477

  7. Structural basis for the antibody neutralization of Herpes simplex virus

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Cheng-Chung; Lin, Li-Ling [Academia Sinica, Taipei 115, Taiwan (China); Academia Sinica, Taipei 115, Taiwan (China); Chan, Woan-Eng [Development Center for Biotechnology, New Taipei City 221, Taiwan (China); Ko, Tzu-Ping [Academia Sinica, Taipei 115, Taiwan (China); Academia Sinica, Taipei 115, Taiwan (China); Lai, Jiann-Shiun [Development Center for Biotechnology, New Taipei City 221, Taiwan (China); Ministry of Economic Affairs, Taipei 100, Taiwan (China); Wang, Andrew H.-J., E-mail: ahjwang@gate.sinica.edu.tw [Academia Sinica, Taipei 115, Taiwan (China); Academia Sinica, Taipei 115, Taiwan (China); Taipei Medical University, Taipei 110, Taiwan (China)

    2013-10-01

    The gD–E317-Fab complex crystal revealed the conformational epitope of human mAb E317 on HSV gD, providing a molecular basis for understanding the viral neutralization mechanism. Glycoprotein D (gD) of Herpes simplex virus (HSV) binds to a host cell surface receptor, which is required to trigger membrane fusion for virion entry into the host cell. gD has become a validated anti-HSV target for therapeutic antibody development. The highly inhibitory human monoclonal antibody E317 (mAb E317) was previously raised against HSV gD for viral neutralization. To understand the structural basis of antibody neutralization, crystals of the gD ectodomain bound to the E317 Fab domain were obtained. The structure of the complex reveals that E317 interacts with gD mainly through the heavy chain, which covers a large area for epitope recognition on gD, with a flexible N-terminal and C-terminal conformation. The epitope core structure maps to the external surface of gD, corresponding to the binding sites of two receptors, herpesvirus entry mediator (HVEM) and nectin-1, which mediate HSV infection. E317 directly recognizes the gD–nectin-1 interface and occludes the HVEM contact site of gD to block its binding to either receptor. The binding of E317 to gD also prohibits the formation of the N-terminal hairpin of gD for HVEM recognition. The major E317-binding site on gD overlaps with either the nectin-1-binding residues or the neutralizing antigenic sites identified thus far (Tyr38, Asp215, Arg222 and Phe223). The epitopes of gD for E317 binding are highly conserved between two types of human herpesvirus (HSV-1 and HSV-2). This study enables the virus-neutralizing epitopes to be correlated with the receptor-binding regions. The results further strengthen the previously demonstrated therapeutic and diagnostic potential of the E317 antibody.

  8. Development and characterization of human monoclonal antibodies that neutralize multiple TGFβ isoforms.

    Science.gov (United States)

    Bedinger, Daniel; Lao, Llewelyn; Khan, Shireen; Lee, Steve; Takeuchi, Toshihiko; Mirza, Amer M

    2016-01-01

    Transforming growth factor (TGF)β levels are elevated in, and drive the progression of, numerous disease states such as advanced metastatic cancer and systemic and ocular fibrosis. There are 3 main isoforms, TGFβ1, 2, and 3. As multiple TGFβ isoforms are involved in disease processes, maximal therapeutic efficacy may require neutralization of 2 or more of the TGFβ isoforms. Fully human antibody phage display libraries were used to discover a number of antibodies that bind and neutralize various combinations of TGFβ1, 2 or 3. The primary panning did not yield any uniformly potent pan-isoform neutralizing antibodies; therefore, an antibody that displayed potent TGFβ 1, 2 inhibition, but more modest affinity versus TGFβ3, was affinity matured by shuffling with a light chain sub-library and further screening. This process yielded a high affinity pan-isoform neutralizing clone. Antibodies were analyzed and compared by binding affinity, as well as receptor and epitope competition by surface plasmon resonance methods. The antibodies were also shown to neutralize TGFβ effects in vitro in 3 assays: 1) interleukin (IL)-4 induced HT-2 cell proliferation; 2) TGFβ-mediated IL-11 release by A549 cells; and 3) decreasing SMAD2 phosphorylation in Detroit 562 cells. The antibodies' potency in these in vitro assays correlated well with their isoform-specific affinities. Furthermore, the ability of the affinity-matured clone to decrease tumor burden in a Detroit 562 xenograft study was superior to that of the parent clone. This affinity-matured antibody acts as a very potent inhibitor of all 3 main isoforms of TGFβ and may have utility for therapeutic intervention in human disease.

  9. IgG4 subclass antibodies impair antitumor immunity in melanoma

    Science.gov (United States)

    Karagiannis, Panagiotis; Gilbert, Amy E.; Josephs, Debra H.; Ali, Niwa; Dodev, Tihomir; Saul, Louise; Correa, Isabel; Roberts, Luke; Beddowes, Emma; Koers, Alexander; Hobbs, Carl; Ferreira, Silvia; Geh, Jenny L.C.; Healy, Ciaran; Harries, Mark; Acland, Katharine M.; Blower, Philip J.; Mitchell, Tracey; Fear, David J.; Spicer, James F.; Lacy, Katie E.; Nestle, Frank O.; Karagiannis, Sophia N.

    2013-01-01

    Host-induced antibodies and their contributions to cancer inflammation are largely unexplored. IgG4 subclass antibodies are present in IL-10–driven Th2 immune responses in some inflammatory conditions. Since Th2-biased inflammation is a hallmark of tumor microenvironments, we investigated the presence and functional implications of IgG4 in malignant melanoma. Consistent with Th2 inflammation, CD22+ B cells and IgG4+-infiltrating cells accumulated in tumors, and IL-10, IL-4, and tumor-reactive IgG4 were expressed in situ. When compared with B cells from patient lymph nodes and blood, tumor-associated B cells were polarized to produce IgG4. Secreted B cells increased VEGF and IgG4, and tumor cells enhanced IL-10 secretion in cocultures. Unlike IgG1, an engineered tumor antigen-specific IgG4 was ineffective in triggering effector cell–mediated tumor killing in vitro. Antigen-specific and nonspecific IgG4 inhibited IgG1-mediated tumoricidal functions. IgG4 blockade was mediated through reduction of FcγRI activation. Additionally, IgG4 significantly impaired the potency of tumoricidal IgG1 in a human melanoma xenograft mouse model. Furthermore, serum IgG4 was inversely correlated with patient survival. These findings suggest that IgG4 promoted by tumor-induced Th2-biased inflammation may restrict effector cell functions against tumors, providing a previously unexplored aspect of tumor-induced immune escape and a basis for biomarker development and patient-specific therapeutic approaches. PMID:23454746

  10. Thyroid Antibodies

    Science.gov (United States)

    ... PF4 Antibody Hepatitis A Testing Hepatitis B Testing Hepatitis C Testing HER2/neu Herpes Testing High-sensitivity C-reactive Protein (hs-CRP) Histamine Histone Antibody HIV Antibody and HIV Antigen (p24) HIV Antiretroviral Drug Resistance Testing, Genotypic HIV Viral Load HLA Testing HLA- ...

  11. A type I interferon signature characterizes chronic antibody-mediated rejection in kidney transplantation.

    Science.gov (United States)

    Rascio, Federica; Pontrelli, Paola; Accetturo, Matteo; Oranger, Annarita; Gigante, Margherita; Castellano, Giuseppe; Gigante, Maddalena; Zito, Anna; Zaza, Gianluigi; Lupo, Antonio; Ranieri, Elena; Stallone, Giovanni; Gesualdo, Loreto; Grandaliano, Giuseppe

    2015-09-01

    Chronic antibody-mediated rejection (CAMR) represents the main cause of kidney graft loss. To uncover the molecular mechanisms underlying this condition, we characterized the molecular signature of peripheral blood mononuclear cells (PBMCs) and, separately, of CD4(+) T lymphocytes isolated from CAMR patients, compared to kidney transplant recipients with normal graft function and histology. We enrolled 29 patients with biopsy-proven CAMR, 29 stable transplant recipients (controls), and 8 transplant recipients with clinical and histological evidence of interstitial fibrosis/tubular atrophy. Messenger RNA and microRNA profiling of PBMCs and CD4(+) T lymphocytes was performed using Agilent microarrays in eight randomly selected patients per group from CAMR and control subjects. Results were evaluated statistically and by functional pathway analysis (Ingenuity Pathway Analysis) and validated in the remaining subjects. In PBMCs, 45 genes were differentially expressed between the two groups, most of which were up-regulated in CAMR and were involved in type I interferon signalling. In the same patients, 16 microRNAs were down-regulated in CAMR subjects compared to controls: four were predicted modulators of six mRNAs identified in the transcriptional analysis. In silico functional analysis supported the involvement of type I interferon signalling. To further confirm this result, we investigated the transcriptomic profiles of CD4(+) T lymphocytes in an independent group of patients, observing that the activation of type I interferon signalling was a specific hallmark of CAMR. In addition, in CAMR patients, we detected a reduction of circulating BDCA2(+) dendritic cells, the natural type I interferon-producing cells, and their recruitment into the graft along with increased expression of MXA, a type I interferon-induced protein, at the tubulointerstitial and vascular level. Finally, interferon alpha mRNA expression was significantly increased in CAMR compared to control

  12. Future strategy and puzzles of heavy ion beam mediated technique in genetic improvement of biological bodies

    International Nuclear Information System (INIS)

    Huang Qunce

    2007-01-01

    The 7 research puzzles in the genetic improvement of biological bodies made by ion beam mediated technique, are worth noticed. The technical ideas, including one mediated technique in physics, 2 significant subjects, 3 effective changes, the mediated evidences of 4 aspects and 5 biological characteristics, were particularly put forward according to the existing states in the field. The 2 significant subjects consist of the mechanics of the allogenetic materials entering into the acceptor and they being to be recombined. The 3 effective changes include from studying morphology to genetic laws, from researching M1 generation to the next generations, from determining the single character to the synthetic traits. The mediated evidences of 4 aspects come from morphology, physiology and biochemistry, molecule biology. The 5 biological characteristics are mainly reproduction, development, photosynthesis, bad condition-resistant and quality. (authors)

  13. Post-infection immunodeficiency virus control by neutralizing antibodies.

    Directory of Open Access Journals (Sweden)

    Hiroyuki Yamamoto

    Full Text Available BACKGROUND: Unlike most acute viral infections controlled with the appearance of virus-specific neutralizing antibodies (NAbs, primary HIV infections are not met with such potent and early antibody responses. This brings into question if or how the presence of potent antibodies can contribute to primary HIV control, but protective efficacies of antiviral antibodies in primary HIV infections have remained elusive; and, it has been speculated that even NAb induction could have only a limited suppressive effect on primary HIV replication once infection is established. Here, in an attempt to answer this question, we examined the effect of passive NAb immunization post-infection on primary viral replication in a macaque AIDS model. METHODS AND FINDINGS: The inoculums for passive immunization with simian immunodeficiency virus mac239 (SIVmac239-specific neutralizing activity were prepared by purifying polyclonal immunoglobulin G from pooled plasma of six SIVmac239-infected rhesus macaques with NAb induction in the chronic phase. Passive immunization of rhesus macaques with the NAbs at day 7 after SIVmac239 challenge resulted in significant reduction of set-point plasma viral loads and preservation of central memory CD4 T lymphocyte counts, despite the limited detection period of the administered NAb responses. Peripheral lymph node dendritic cell (DC-associated viral RNA loads showed a remarkable peak with the NAb administration, and DCs stimulated in vitro with NAb-preincubated SIV activated virus-specific CD4 T lymphocytes in an Fc-dependent manner, implying antibody-mediated virion uptake by DCs and enhanced T cell priming. CONCLUSIONS: Our results present evidence indicating that potent antibody induction post-infection can result in primary immunodeficiency virus control and suggest direct and indirect contribution of its absence to initial control failure in HIV infections. Although difficulty in achieving requisite neutralizing titers for

  14. Improvement of Radiation-Mediated Immunosuppression of Human NSCLC Tumour Xenografts in a Nude Rat Model

    Directory of Open Access Journals (Sweden)

    Sergey V. Tokalov

    2010-01-01

    Full Text Available Human tumour xenografts in a nude rat model have consistently been used as an essential part of preclinical studies for anticancer drugs activity in human. Commonly, these animals receive whole body irradiation to assure immunosuppression. But whole body dose delivery might be inhomogeneous and the resulting incomplete bone marrow depletion may modify tumour behaviour. To improve irradiation-mediated immunosuppression of human non-small cell lung cancer (NSCLC xenografts in a nude rat model irradiation (2 + 2 Gy from opposite sides of animals has been performed using a conventional X-ray tube. The described modification of whole body irradiation improves growth properties of human NSCLC xenografts in a nude rat model. The design of the whole body irradiation mediated immunosuppression described here for NSCLC xenografts may be useful for research applications involving other types of human tumours.

  15. Radiolabeled antibody imaging

    International Nuclear Information System (INIS)

    Wahl, R.L.

    1987-01-01

    Radiolabeled antibodies, in particular monoclonal antibodies, offer the potential for the specific nuclear imaging of malignant and benign diseases in man. If this imaging potential is realized, they may also have a large role in cancer treatment. This paper reviews: (1) what monoclonal antibodies are and how they differ from polyclonal antibodies, (2) how they are produced and radiolabeled, (3) the results of preclinical and clinical trials in cancer imaging, including the utility of SPECT and antibody fragments, (4) the role of antibodies in the diagnosis of benign diseases, (5) alternate routes of antibody delivery, (6) the role of these agents in therapy, and (7) whether this technology ''revolutionizes'' the practice of nuclear radiology, or has a more limited complementary role in the imaging department

  16. Diagnosis of hypersensitivity pneumonitis by measurement of antibodies against environmental antigens

    International Nuclear Information System (INIS)

    Dewair, M.

    1989-01-01

    Hypersensitivity pneumonitis (HP), an immunologically mediated chronic pulmonary disease, is the result of an inflammatory response of the lung initiated by the inhalation of environmental organic dusts. These organic dusts usually contain substances (antigens) capable of eliciting immune responses in humans. The symptoms of HP generally present as recurrent flu-like episodes which makes it difficult to establish the proper diagnosis. However, detection in patients' sera of high-titer antibodies against the environmental antigens could be of great help in identifying those materials causing the disease and which must be avoided. A highly specific and sensitive serodiagnostic test, a radioimmuno assay (RIA), was developed for measurement of antibodies against antigens relevant to Farmer's Lung Disease (FLD), a type of HP affecting farmers

  17. E-selectin: sialyl Lewis, a dependent adhesion of colon cancer cells, is inhibited differently by antibodies against E-selectin ligands.

    Science.gov (United States)

    Srinivas, U; Påhlsson, P; Lundblad, A

    1996-09-01

    Recent studies have demonstrated that selectins, a new family of cell-adhesion molecules with similar domain structures, mediate the adhesion of peripheral blood cells to interleukin-1 (IL-1)-activated endothelium. In the present study the authors evaluated the role of E-selectin-Sialyl Lewis x (SLe(x))/ Sialyl Lewis a (SLe(a)) interaction in mediating in vitro adhesion of two colon cancer cell lines, HT-29 and COLO 201, to human umbilical cord endothelial cells (HUVEC). Colon cancer cell lines had a strong expression of blood group-related carbohydrate epitopes as evaluated by fluorescence-activated cell sorter (FACS) analysis. It was established that adhesion of HT-29 and COLO 201 cells to IL-1 stimulated HUVEC was calcium dependent and could be inhibited by a monoclonal antibody directed against E-selectin. Prior incubation of cells with two different antibodies directed against SLe(x) and antibodies directed against related Lewis epitopes, Le(x) and Le(a), had no significant effect on adhesion. Three antibodies directed against SLe(a) differed in their capacity to inhibit the adhesion of HT-29 and COLO 201 cells to HUVEC. Only one antibody directed against the SLe(a) structure was effective in inhibiting adhesion of both COLO 201 and HT-29 cells. The difference could not be attributed to titre, the type or number of glycoproteins, or to a difference in the amount of SLe(a) present on individual proteins, suggesting that presence and right presentation of SLe(a) epitope might be important for adhesion of colon cancer cells. Finally, in the in vitro system used, adhesion of HT-29 and COLO 201 cells to activated HUVEC is mediated predominantly by E-selectin/SLe(a) interaction. SLe(x) and related epitopes, Le(x) and Le(a), seem to have limited relevance for colon cancer cell recognition of E-selectin.

  18. Measurement of IgG antibodies to house dust mite and grass pollen by a solid-phase radioimmunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Delespesse, G; Debisschop, M J; Flament, J [Hopital Saint Pierre, Louvain (Belgium). Lab. de Recherches de la Clinique Medicale

    1979-09-01

    A solid-phase radioimmunoassay was used to measure specific IgG antibodies to either Dermatophagoides pteronyssinus (DPT) or grass pollens. Radiolabelled protein A from Staphylococcus aureus (SpA) was used to determine the IgG antibodies attached to the microtubes. The binding of IgG from either normal or allergic sera to DPT-coated tubes was antigen specific and mediated by the Fab fragment of the immunoglobulin. IgG antibodies from non-allergic serum competed with IgE antibodies to DPT. IgE antibodies did not significantly interfere with the assay. Indeed heating a reaginic serum resulted in a striking reduction of the (/sup 125/I) anti- IgE binding to allergen-coated tubes without modifying the (/sup 125/I)-SpA binding. Furthermore, filtration of a reaginic serum through Sephacryl S-200 separated a peak of IgE antibodies. The solid phase method was more sensitive than a double-antibody technique employing the same DPT extract as labelled antigen. Non-allergic subjects had less IgG antibodies to DPT or grass pollens than allergic patients. In untreated patients, there was a good correlation between levels of IgG and IgE antibodies to grass pollens but not to DPT. Patients hyposensitized to house dust mite had on the average three times more specific IgG antibodies than untreated cases. (author).

  19. Measurement of IgG antibodies to house dust mite and grass pollen by a solid-phase radioimmunoassay

    International Nuclear Information System (INIS)

    Delespesse, G.; Debisschop, M.J.; Flament, J.

    1979-01-01

    A solid-phase radioimmunoassay was used to measure specific IgG antibodies to either Dermatophagoides pteronyssinus (DPT) or grass pollens. Radiolabelled protein A from Staphylococcus aureus (SpA) was used to determine the IgG antibodies attached to the microtubes. The binding of IgG from either normal or allergic sera to DPT-coated tubes was antigen specific and mediated by the Fab fragment of the immunoglobulin. IgG antibodies from non-allergic serum competed with IgE antibodies to DPT. IgE antibodies did not significantly interfere with the assay. Indeed heating a reaginic serum resulted in a striking reduction of the ( 125 I) anti- IgE binding to allergen-coated tubes without modifying the ( 125 I)-SpA binding. Furthermore, filtration of a reaginic serum through Sephacryl S-200 separated a peak of IgE antibodies. The solid phase method was more sensitive than a double-antibody technique employing the same DPT extract as labelled antigen. Non-allergic subjects had less IgG antibodies to DPT or grass pollens than allergic patients. In untreated patients, there was a good correlation between levels of IgG and IgE antibodies to grass pollens but not to DPT. Patients hyposensitized to house dust mite had on the average three times more specific IgG antibodies than untreated cases. (author)

  20. Human monoclonal antibodies: the residual challenge of antibody immunogenicity.

    Science.gov (United States)

    Waldmann, Herman

    2014-01-01

    One of the major reasons for seeking human monoclonal antibodies has been to eliminate immunogenicity seen with rodent antibodies. Thus far, there has yet been no approach which absolutely abolishes that risk for cell-binding antibodies. In this short article, I draw attention to classical work which shows that monomeric immunoglobulins are intrinsically tolerogenic if they can be prevented from creating aggregates or immune complexes. Based on these classical studies two approaches for active tolerization to therapeutic antibodies are described.