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Sample records for human igg fc

  1. Structural characterization of the Man5 glycoform of human IgG3 Fc

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    Shah, Ishan S.; Lovell, Scott; Mehzabeen, Nurjahan; Battaile, Kevin P.; Tolbert, Thomas J. (Kansas); (HWMRI)

    2017-12-01

    Immunoglobulin G (IgG) consists of four subclasses in humans: IgG1, IgG2, IgG3 and IgG4, which are highly conserved but have unique differences that result in subclass-specific effector functions. Though IgG1 is the most extensively studied IgG subclass, study of other subclasses is important to understand overall immune function and for development of new therapeutics. When compared to IgG1, IgG3 exhibits a similar binding profile to Fcγ receptors and stronger activation of complement. All IgG subclasses are glycosylated at N297, which is required for Fcγ receptor and C1q complement binding as well as maintaining optimal Fc conformation. We have determined the crystal structure of homogenously glycosylated human IgG3 Fc with a GlcNAc2Man5 (Man5) high mannose glycoform at 1.8 Å resolution and compared its structural features with published structures from the other IgG subclasses. Although the overall structure of IgG3 Fc is similar to that of other subclasses, some structural perturbations based on sequence differences were revealed. For instance, the presence of R435 in IgG3 (and H435 in the other IgG subclasses) has been implicated to result in IgG3-specific properties related to binding to protein A, protein G and the neonatal Fc receptor (FcRn). The IgG3 Fc structure helps to explain some of these differences. Additionally, protein-glycan contacts observed in the crystal structure appear to correlate with IgG3 affinity for Fcγ receptors as shown by binding studies with IgG3 Fc glycoforms. Finally, this IgG3 Fc structure provides a template for further studies aimed at engineering the Fc for specific gain of function.

  2. Traces of pFc' in IVIG interact with human IgG Fc domains and counteract aggregation

    NARCIS (Netherlands)

    Rispens, Theo; Himly, Martin; Ooievaar-de Heer, Pleuni; den Bleker, Tamara H.; Aalberse, Rob C.

    2010-01-01

    To prevent multimer formation, intravenous immunoglobulin (IVIG) is often treated with traces of pepsin. So far, the mechanism behind this treatment has been unclear. Recently, we reported that human IgG4 binds other IgG molecules via Fc-Fc interactions. Here we show that IVIG treated with traces of

  3. Human IgG4 binds to IgG4 and conformationally altered IgG1 via Fc-Fc interactions

    NARCIS (Netherlands)

    Rispens, Theo; Ooievaar-de Heer, Pleuni; Vermeulen, Ellen; Schuurman, Janine; van der Neut Kolfschoten, Marijn; Aalberse, Rob C.

    2009-01-01

    The Fc fragment of IgG4 can interact with the Fc fragment of another IgG molecule. This interaction is a confounding factor when measuring IgG4 rheumatoid factor levels. Recently, we demonstrated that half-molecules of IgG4 can exchange to form a bispecific Ab. We expected these two phenomena to be

  4. Potential of Murine IgG1 and Human IgG4 to Inhibit the Classical Complement and Fcγ Receptor Activation Pathways

    Directory of Open Access Journals (Sweden)

    Gina-Maria Lilienthal

    2018-05-01

    Full Text Available IgG antibodies (Abs mediate their effector functions through the interaction with Fcγ receptors (FcγRs and the complement factors. The main IgG-mediated complement activation pathway is induced through the binding of complement C1q to IgG Abs. This interaction is dependent on antigen-dependent hexamer formation of human IgG1 and IgG3 to increase the affinity for the six-headed C1q molecule. By contrast, human IgG4 fails to bind to C1q. Instead, it has been suggested that human IgG4 can block IgG1 and IgG3 hexamerization required for their binding to C1q and activating the complement. Here, we show that murine IgG1, which functionally resembles human IgG4 by not interacting with C1q, inhibits the binding of IgG2a, IgG2b, and IgG3 to C1q in vitro, and suppresses IgG2a-mediated complement activation in a hemolytic assay in an antigen-dependent and IgG subclass-specific manner. From this perspective, we discuss the potential of murine IgG1 and human IgG4 to block the complement activation as well as suppressive effects of sialylated IgG subclass Abs on FcγR-mediated immune cell activation. Accumulating evidence suggests that both mechanisms seem to be responsible for preventing uncontrolled IgG (autoAb-induced inflammation in mice and humans. Distinct IgG subclass distributions and functionally opposite IgG Fc glycosylation patterns might explain different outcomes of IgG-mediated immune responses and provide new therapeutic options through the induction, enrichment, or application of antigen-specific sialylated human IgG4 to prevent complement and FcγR activation as well.

  5. Human IgG lacking effector functions demonstrate lower FcRn-binding and reduced transplacental transport

    NARCIS (Netherlands)

    Stapleton, Nigel M.; Armstrong-Fisher, Sylvia S.; Andersen, Jan Terje; van der Schoot, C. Ellen; Porter, Charlene; Page, Kenneth R.; Falconer, Donald; de Haas, Masja; Williamson, Lorna M.; Clark, Michael R.; Vidarsson, Gestur; Armour, Kathryn L.

    2018-01-01

    We have previously generated human IgG1 antibodies that were engineered for reduced binding to the classical Fcγ receptors (FcγRI-III) and C1q, thereby eliminating their destructive effector functions (constant region G1Δnab). In their potential use as blocking agents, favorable binding to the

  6. Human IgG lacking effector functions demonstrate lower FcRn-binding and reduced transplacental transport.

    Science.gov (United States)

    Stapleton, Nigel M; Armstrong-Fisher, Sylvia S; Andersen, Jan Terje; van der Schoot, C Ellen; Porter, Charlene; Page, Kenneth R; Falconer, Donald; de Haas, Masja; Williamson, Lorna M; Clark, Michael R; Vidarsson, Gestur; Armour, Kathryn L

    2018-03-01

    We have previously generated human IgG1 antibodies that were engineered for reduced binding to the classical Fcγ receptors (FcγRI-III) and C1q, thereby eliminating their destructive effector functions (constant region G1Δnab). In their potential use as blocking agents, favorable binding to the neonatal Fc receptor (FcRn) is important to preserve the long half-life typical of IgG. An ability to cross the placenta, which is also mediated, at least in part, by FcRn is desirable in some indications, such as feto-maternal alloimmune disorders. Here, we show that G1Δnab mutants retain pH-dependent binding to human FcRn but that the amino acid alterations reduce the affinity of the IgG1:FcRn interaction by 2.0-fold and 1.6-fold for the two antibodies investigated. The transport of the modified G1Δnab mutants across monolayers of human cell lines expressing FcRn was approximately 75% of the wild-type, except that no difference was observed with human umbilical vein endothelial cells. G1Δnab mutation also reduced transport in an ex vivo placenta model. In conclusion, we demonstrate that, although the G1Δnab mutations are away from the FcRn-binding site, they have long-distance effects, modulating FcRn binding and transcellular transport. Our findings have implications for the design of therapeutic human IgG with tailored effector functions. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Absolute Quantitation of Glycoforms of Two Human IgG Subclasses Using Synthetic Fc Peptides and Glycopeptides

    Science.gov (United States)

    Roy, Rini; Ang, Evelyn; Komatsu, Emy; Domalaon, Ronald; Bosseboeuf, Adrien; Harb, Jean; Hermouet, Sylvie; Krokhin, Oleg; Schweizer, Frank; Perreault, Hélène

    2018-05-01

    Immunoglobulins, such as immunoglobulin G (IgG), are of prime importance in the immune system. Polyclonal human IgG comprises four subclasses, of which IgG1 and IgG2 are the most abundant in healthy individuals. In an effort to develop an absolute MALDI-ToF-MS quantitative method for these subclasses and their Fc N-glycoforms, (glyco)peptides were synthesized using a solid-phase approach and used as internal standards. Tryptic digest glycopeptides from monoclonal IgG1 and IgG2 samples were first quantified using EEQYN(GlcNAc)STYR and EEQFN(GlcNAc)STFR standards, respectively. For IgG1, a similar glycopeptide where tyrosine (Y) was isotopically labelled was used to quantify monoclonal IgG1 that had been treated with the enzyme Endo-F2, i.e., yielding tryptic glycopeptide EEQYN(GlcNAc)STYR. The next step was to quantify single subclasses within polyclonal human IgG samples. Although ion abundances in the MALDI spectra often showed higher signals for IgG2 than IgG1, depending on the spotting solvent used, determination of amounts using the newly developed quantitative method allowed to obtain accurate concentrations where IgG1 species were predominant. It was observed that simultaneous analysis of IgG1 and IgG2 yielded non-quantitative results and that more success was obtained when subclasses were quantified one by one. More experiments served to assess the respective extraction and ionization efficiencies of EEQYNSTYR/EEQFNSTFR and EEQYN(GlcNAc)STYR/EEQFN(GlcNAc)STFR mixtures under different solvent and concentration conditions.

  8. Importance of neonatal FcR in regulating the serum half-life of therapeutic proteins containing the Fc domain of human IgG1: a comparative study of the affinity of monoclonal antibodies and Fc-fusion proteins to human neonatal FcR.

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    Suzuki, Takuo; Ishii-Watabe, Akiko; Tada, Minoru; Kobayashi, Tetsu; Kanayasu-Toyoda, Toshie; Kawanishi, Toru; Yamaguchi, Teruhide

    2010-02-15

    The neonatal FcR (FcRn) binds to the Fc domain of IgG at acidic pH in the endosome and protects IgG from degradation, thereby contributing to the long serum half-life of IgG. To date, more than 20 mAb products and 5 Fc-fusion protein products have received marketing authorization approval in the United States, the European Union, or Japan. Many of these therapeutic proteins have the Fc domain of human IgG1; however, the serum half-lives differ in each protein. To elucidate the role of FcRn in the pharmacokinetics of Fc domain-containing therapeutic proteins, we evaluated the affinity of the clinically used human, humanized, chimeric, or mouse mAbs and Fc-fusion proteins to recombinant human FcRn by surface plasmon resonance analysis. The affinities of these therapeutic proteins to FcRn were found to be closely correlated with the serum half-lives reported from clinical studies, suggesting the important role of FcRn in regulating their serum half-lives. The relatively short serum half-life of Fc-fusion proteins was thought to arise from the low affinity to FcRn. The existence of some mAbs having high affinity to FcRn and a short serum half-life, however, suggested the involvement of other critical factor(s) in determining the serum half-life of such Abs. We further investigated the reason for the relatively low affinity of Fc-fusion proteins to FcRn and suggested the possibility that the receptor domain of Fc-fusion protein influences the structural environment of the FcRn binding region but not of the FcgammaRI binding region of the Fc domain.

  9. Intracellular calcium mobilization in human lymphocytes in the presence of synthetic IgG Fc peptides

    International Nuclear Information System (INIS)

    Plummer, J.M.; Panahi, Y.P.; McClurg, M.R.; Hahn, G.S.; Naemura, J.R.

    1986-01-01

    Certain synthetic peptides derived from the Fc region of human IgG can suppress the mixed lymphocyte response. These peptides were tested for the ability to induce intracellular calcium mobilization in human lymphocytes using fura-2/calcium fluorescence. T cells were isolated by rosetting and were > 90% OKT3 positive. Lymphocytes were incubated with the acetoxymethyl ester of fura-2 (10 μM) for 60 minutes at 37 0 C. Fluorescence intensity changes at 505 nm were monitored at an excitation lambda of 340 nm. Fura-2 was not cytotoxic compared to quin-2 since fura-2 loaded mononuclear cells incorporated 3 H-thymidine when stimulated by PHA, succinyl Con A, PWM or LPS-STM whereas quin-2 loaded cells showed a dose dependent inhibition of proliferation. Those synthetic peptides (5 to 400 μg/ml) that suppressed the MLR induced a dose dependent increase in intracellular calcium in mononuclear cells, lymphocytes, non-T cells and T cells. The fura-2 calcium fluorescence time course response was similar for peptide, PHA and succinyl Con A. These results suggest that these immunoregulatory peptides suppress 3 H-thymidine incorporation at a point after intracellular calcium mobilization and that fura-2 has advantages over quin-2 in measuring intracellular calcium levels in lymphocytes

  10. Fc-Glycosylation in Human IgG1 and IgG3 Is Similar for Both Total and Anti-Red-Blood Cell Anti-K Antibodies

    Directory of Open Access Journals (Sweden)

    Myrthe E. Sonneveld

    2018-01-01

    Full Text Available After albumin, immunoglobulin G (IgG are the most abundant proteins in human serum, with IgG1 and IgG3 being the most abundant subclasses directed against protein antigens. The quality of the IgG-Fc-glycosylation has important functional consequences, which have been found to be skewed toward low fucosylation in some antigen-specific immune responses. This increases the affinity to IgG1-Fc-receptor (FcγRIIIa/b and thereby directly affects downstream effector functions and disease severity. To date, antigen-specific IgG-glycosylation have not been analyzed for IgG3. Here, we analyzed 30 pregnant women with anti-K alloantibodies from a prospective screening cohort and compared the type of Fc-tail glycosylation of total serum- and antigen-specific IgG1 and IgG3 using mass spectrometry. Total serum IgG1 and IgG3 Fc-glycoprofiles were highly similar. Fc glycosylation of antigen-specific IgG varied greatly between individuals, but correlated significantly with each other for IgG1 and IgG3, except for bisection. However, although the magnitude of changes in fucosylation and galactosylation were similar for both subclasses, this was not the case for sialylation levels, which were significantly higher for both total and anti-K IgG3. We found that the combination of relative IgG1 and IgG3 Fc-glycosylation levels did not improve the prediction of anti-K mediated disease over IgG1 alone. In conclusion, Fc-glycosylation profiles of serum- and antigen-specific IgG1 and IgG3 are highly similar.

  11. Comparison of the Fc fragment from a human IgG1 and its CH2, pFc', and tFc' subfragments. A study using reductive methylation and 13C NMR

    International Nuclear Information System (INIS)

    Jentoft, J.E.; Rayford, R.

    1989-01-01

    The Fc fragment of a human monoclonal IgG1 was compared with subfragments containing (a) the intact CH2 domain (CH2 fragment) or (b) the intact CH3 domain (pFc' and tFc' fragments). All fragments were reductively 13 C-methylated and their resulting dimethyllysyl resonances characterized in 0.1 M KCl as a function of pH by 13 C NMR spectroscopy. Seven resonances were characterized for the 18 lysine residues of the Fc fragment, eight for the 12 lysines of the CH2 fragment, and five each for the 9 lysines of the pFc' and the 6 lysines of the tFc' fragments, respectively. The multiplicity of resonances indicates that the lysine residues in each fragment exist in a variety of microenvironments and that the fragments are all highly structured. The correspondence between 6 of the 12 or 13 perturbed lysine residues in the Fc fragment and the smaller subfragments indicates that the conformation of the CH2 and CH3 domains is largely unchanged in the smaller fragments. However, in addition to three lysines at the CH2-CH3 domain interface, whose environments were known to be disrupted in the smaller fragments, three or four lysine residues have somewhat different properties in the Fc fragment and in the subfragments, indicating that some local perturbations are included in the domain structure in the subfragments

  12. Fc receptors for mouse IgG1 on human monocytes: polymorphism and role in antibody-induced T cell proliferation.

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    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

  13. Structural insights into the interaction of human IgG1 with FcγRI: no direct role of glycans in binding

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    Oganesyan, Vaheh, E-mail: oganesyanv@medimmune.com; Mazor, Yariv; Yang, Chunning; Cook, Kimberly E.; Woods, Robert M. [MedImmune LLC, 1 MedImmune Way, Gaithersburg, MD 20878 (United States); Ferguson, Andrew [AstraZeneca Pharmaceuticals, 35 Gatehouse Drive, Mailstop E3, Waltham, MA 02451 (United States); Bowen, Michael A.; Martin, Tom; Zhu, Jie; Wu, Herren; Dall’Acqua, William F., E-mail: oganesyanv@medimmune.com [MedImmune LLC, 1 MedImmune Way, Gaithersburg, MD 20878 (United States)

    2015-10-31

    In an effort to identify the critical structural features responsible for the high-affinity interaction of IgG1 Fc with FcγRI, the structure of the corresponding complex was solved at a resolution of 2.4 Å. The three-dimensional structure of a human IgG1 Fc fragment bound to wild-type human FcγRI is reported. The structure of the corresponding complex was solved at a resolution of 2.4 Å using molecular replacement; this is the highest resolution achieved for an unmutated FcγRI molecule. This study highlights the critical structural and functional role played by the second extracellular subdomain of FcγRI. It also explains the long-known major energetic contribution of the Fc ‘LLGG’ motif at positions 234–237, and particularly of Leu235, via a ‘lock-and-key’ mechanism. Finally, a previously held belief is corrected and a differing view is offered on the recently proposed direct role of Fc carbohydrates in the corresponding interaction. Structural evidence is provided that such glycan-related effects are strictly indirect.

  14. Crystallization and preliminary X-ray diffraction studies of an RNA aptamer in complex with the human IgG Fc fragment

    International Nuclear Information System (INIS)

    Sugiyama, Shigeru; Nomura, Yusuke; Sakamoto, Taiichi; Kitatani, Tomoya; Kobayashi, Asako; Miyakawa, Shin; Takahashi, Yoshinori; Adachi, Hiroaki; Takano, Kazufumi; Murakami, Satoshi; Inoue, Tsuyoshi; Mori, Yusuke; Nakamura, Yoshikazu; Matsumura, Hiroyoshi

    2008-01-01

    An RNA aptamer in complex with the human IgG Fc fragment have been crystallized. The stirring technique with a rotary shaker was used to improve the crystals and to ensure that they were of high quality and single, resulting in crystals that diffracted to 2.2 Å resolution. Aptamers, which are folded DNA or RNA molecules, bind to target molecules with high affinity and specificity. An RNA aptamer specific for the Fc fragment of human immunoglobulin G (IgG) has recently been identified and it has been demonstrated that an optimized 24-nucleotide RNA aptamer binds to the Fc fragment of human IgG and not to other species. In order to clarify the structural basis of the high specificity of the RNA aptamer, it was crystallized in complex with the Fc fragment of human IgG1. Preliminary X-ray diffraction studies revealed that the crystals belonged to the orthorhombic space group P2 1 2 1 2, with unit-cell parameters a = 83.7, b = 107.2, c = 79.0 Å. A data set has been collected to 2.2 Å resolution

  15. The Fab Conformations in the Solution Structure of Human Immunoglobulin G4 (IgG4) Restrict Access to Its Fc Region

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    Rayner, Lucy E.; Hui, Gar Kay; Gor, Jayesh; Heenan, Richard K.; Dalby, Paul A.; Perkins, Stephen J.

    2014-01-01

    Human IgG4 antibody shows therapeutically useful properties compared with the IgG1, IgG2, and IgG3 subclasses. Thus IgG4 does not activate complement and shows conformational variability. These properties are attributable to its hinge region, which is the shortest of the four IgG subclasses. Using high throughput scattering methods, we studied the solution structure of wild-type IgG4(Ser222) and a hinge mutant IgG4(Pro222) in different buffers and temperatures where the proline substitution suppresses the formation of half-antibody. Analytical ultracentrifugation showed that both IgG4 forms were principally monomeric with sedimentation coefficients s20,w0 of 6.6–6.8 S. A monomer-dimer equilibrium was observed in heavy water buffer at low temperature. Scattering showed that the x-ray radius of gyration Rg was unchanged with concentration in 50–250 mm NaCl buffers, whereas the neutron Rg values showed a concentration-dependent increase as the temperature decreased in heavy water buffers. The distance distribution curves (P(r)) revealed two peaks, M1 and M2, that shifted below 2 mg/ml to indicate concentration-dependent IgG4 structures in addition to IgG4 dimer formation at high concentration in heavy water. Constrained x-ray and neutron scattering modeling revealed asymmetric solution structures for IgG4(Ser222) with extended hinge structures. The IgG4(Pro222) structure was similar. Both IgG4 structures showed that their Fab regions were positioned close enough to the Fc region to restrict C1q binding. Our new molecular models for IgG4 explain its inability to activate complement and clarify aspects of its stability and function for therapeutic applications. PMID:24876381

  16. A recombinant mimetics of the HIV-1 gp41 prehairpin fusion intermediate fused with human IgG Fc fragment elicits neutralizing antibody response in the vaccinated mice

    International Nuclear Information System (INIS)

    Qi, Zhi; Pan, Chungen; Lu, Hong; Shui, Yuan; Li, Lin; Li, Xiaojuan; Xu, Xueqing; Liu, Shuwen; Jiang, Shibo

    2010-01-01

    Research highlights: → One recombinant mimetics of gp41 prehairpin fusion intermediate (PFI) consisting of gp41 N46 sequence, foldon and IgG Fc, designated N46FdFc, was expressed. → N46FdFc-induced antibodies in mice that neutralized HIV-1 infection, inhibited PIE7 binding to PFI, blocked gp41 six-helix bundle formation, and suppressed HIV-1 mediated cell-cell fusion. → These findings provide an important clue for developing recombinant gp41 PFI mimetics-based HIV vaccines. -- Abstract: HIV-1 gp41 prehairpin fusion intermediate (PFI) composed of three N-terminal heptad repeats (NHR) plays a crucial role in viral fusion and entry and represents an attractive target for anti-HIV therapeutics (e.g., enfuvirtide) and vaccines. In present study, we constructed and expressed two recombinant gp41 PFI mimetics, designated N46Fd and N46FdFc. N46Fd consists of N46 (residues 536-581) in gp41 NHR and foldon (Fd), a trimerization motif. N46FdFc is composed of N46Fd fused with human IgG Fc fragment as an immunoenhancer. We immunized mice with N46 peptide, N46Fd and N46FdFc, respectively, and found that only N46FdFc elicited neutralizing antibody response in mice against infection by HIV-1 strains IIIB (clade B, X4), 92US657 (clade B, R5), and 94UG103 (clade A, X4R5). Anti-N46FdFc antibodies inhibited PIE7 binding to PFI, blocked gp41 six-helix bundle formation, and suppressed HIV-1 mediated cell-cell fusion. These findings provide an important clue for developing recombinant gp41 PFI mimetics-based HIV vaccines.

  17. Complexes prepared from protein A and human serum, IgG, or Fc gamma fragments: characterization by immunochemical analysis of ultracentrifugation fractions and studies on their interconversion.

    Science.gov (United States)

    Langone, J J; Das, C; Mainwaring, R; Shearer, W T

    1985-01-01

    Protein A of Staphylococcus aureus is an Fc receptor for IgG that has been used as a therapeutic reagent to treat cancer in humans and experimental animals. We used ultracentrifugation combined with analysis of isolated fractions by radioimmunoprecipitation and competitive radioimmunoassay with chicken antibodies that bind free protein A or protein A in complexes but do bind free immunoglobulin reagents to localize and characterize the types of complexes formed with different molar ratios of 125I-protein A and human 131I-IgG alone or in serum, and 131I-Fc gamma fragments. This approach offers a distinct advantage over direct counting of radioactivity in the fractions because resolution of complexes and free reagents is much improved. With excess 131I-IgG or 131I-Fc, all the 125I-protein A is present only in complexes that contained 4 molecules of immunoglobulin reagent and 2 molecules of protein A (4:2 complexes), whereas with excess 125I-protein A the stoichiometry of the complexes was 1:1. We have also shown the preformed 4:2 and 1:1 complexes will interconvert in the presence of added excess protein A or IgG, respectively, and that fresh IgG will exchange with IgG or Fc gamma in preformed complexes. Because protein A has been found to elute from an immobilized reagent used in serotherapy of human cancer and is present in a large excess of IgG, the 4:2 complexes may play an active role in the tumoricidal or toxic reactions observed.

  18. Hybrid IgG4/IgG4 Fc antibodies form upon 'Fab-arm' exchange as demonstrated by SDS-PAGE or size-exclusion chromatography

    NARCIS (Netherlands)

    Rispens, Theo; den Bleker, Tamara H.; Aalberse, Rob C.

    2010-01-01

    Human IgG4 antibodies are dynamic molecules that in vivo exchange half-molecules to become bispecific antibodies. Here we show that IgG4 antibodies and IgG4 Fc fragments similarly exchange resulting in hybrid antibodies (a single Fab + Fc) with a molecular weight of ca. 100 kDa. These antibodies can

  19. The neonatal Fc receptor (FcRn) binds independently to both sites of the IgG homodimer with identical affinity.

    Science.gov (United States)

    Abdiche, Yasmina Noubia; Yeung, Yik Andy; Chaparro-Riggers, Javier; Barman, Ishita; Strop, Pavel; Chin, Sherman Michael; Pham, Amber; Bolton, Gary; McDonough, Dan; Lindquist, Kevin; Pons, Jaume; Rajpal, Arvind

    2015-01-01

    The neonatal Fc receptor (FcRn) is expressed by cells of epithelial, endothelial and myeloid lineages and performs multiple roles in adaptive immunity. Characterizing the FcRn/IgG interaction is fundamental to designing therapeutic antibodies because IgGs with moderately increased binding affinities for FcRn exhibit superior serum half-lives and efficacy. It has been hypothesized that 2 FcRn molecules bind an IgG homodimer with disparate affinities, yet their affinity constants are inconsistent across the literature. Using surface plasmon resonance biosensor assays that eliminated confounding experimental artifacts, we present data supporting an alternate hypothesis: 2 FcRn molecules saturate an IgG homodimer with identical affinities at independent sites, consistent with the symmetrical arrangement of the FcRn/Fc complex observed in the crystal structure published by Burmeister et al. in 1994. We find that human FcRn binds human IgG1 with an equilibrium dissociation constant (KD) of 760 ± 60 nM (N = 14) at 25°C and pH 5.8, and shows less than 25% variation across the other human subtypes. Human IgG1 binds cynomolgus monkey FcRn with a 2-fold higher affinity than human FcRn, and binds both mouse and rat FcRn with a 10-fold higher affinity than human FcRn. FcRn/IgG interactions from multiple species show less than a 2-fold weaker affinity at 37°C than at 25°C and appear independent of an IgG's variable region. Our in vivo data in mouse and rat models demonstrate that both affinity and avidity influence an IgG's serum half-life, which should be considered when choosing animals, especially transgenic systems, as surrogates.

  20. Functional characterization of the high affinity IgG Receptor : making heads and tails of FcγRI

    NARCIS (Netherlands)

    van der Poel, C.E.

    2011-01-01

    This thesis focuses on human FcγRI, a high affinity receptor for antibodies of the IgG isotype. IgG is the most abundant antibody type in blood and all currently FDA approved therapeutic antibodies are of the IgG isotype. FcγRI, a member of the activating Fcγ receptors, exists as a complex of a

  1. Human FcγRIIA induces anaphylactic and allergic reactions.

    Science.gov (United States)

    Jönsson, Friederike; Mancardi, David A; Zhao, Wei; Kita, Yoshihiro; Iannascoli, Bruno; Khun, Huot; van Rooijen, Nico; Shimizu, Takao; Schwartz, Lawrence B; Daëron, Marc; Bruhns, Pierre

    2012-03-15

    IgE and IgE receptors (FcεRI) are well-known inducers of allergy. We recently found in mice that active systemic anaphylaxis depends on IgG and IgG receptors (FcγRIIIA and FcγRIV) expressed by neutrophils, rather than on IgE and FcεRI expressed by mast cells and basophils. In humans, neutrophils, mast cells, basophils, and eosinophils do not express FcγRIIIA or FcγRIV, but FcγRIIA. We therefore investigated the possible role of FcγRIIA in allergy by generating novel FcγRIIA-transgenic mice, in which various models of allergic reactions induced by IgG could be studied. In mice, FcγRIIA was sufficient to trigger active and passive anaphylaxis, and airway inflammation in vivo. Blocking FcγRIIA in vivo abolished these reactions. We identified mast cells to be responsible for FcγRIIA-dependent passive cutaneous anaphylaxis, and monocytes/macrophages and neutrophils to be responsible for FcγRIIA-dependent passive systemic anaphylaxis. Supporting these findings, human mast cells, monocytes and neutrophils produced anaphylactogenic mediators after FcγRIIA engagement. IgG and FcγRIIA may therefore contribute to allergic and anaphylactic reactions in humans.

  2. Recombinant IgG1 Fc hexamers block cytotoxicity and pathological changes in experimental in vitro and rat models of neuromyelitis optica.

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    Tradtrantip, Lukmanee; Felix, Christian M; Spirig, Rolf; Morelli, Adriana Baz; Verkman, A S

    2018-05-01

    Intravenous human immunoglobulin G (IVIG) may have therapeutic benefit in neuromyelitis optica spectrum disorders (herein called NMO), in part because of the anti-inflammatory properties of the IgG Fc region. Here, we evaluated recombinant Fc hexamers consisting of the IgM μ-tailpiece fused with the Fc region of human IgG1. In vitro, the Fc hexamers prevented cytotoxicity in aquaporin-4 (AQP4) expressing cells and in rat spinal cord slice cultures exposed to NMO anti-AQP4 autoantibody (AQP4-IgG) and complement, with >500-fold greater potency than IVIG or monomeric Fc fragments. Fc hexamers at low concentration also prevented antibody-dependent cellular cytotoxicity produced by AQP4-IgG and natural killer cells. Serum from rats administered a single intravenous dose of Fc hexamers at 50 mg/kg taken at 8 h did not produce complement-dependent cytotoxicity when added to AQP4-IgG-treated AQP4-expressing cell cultures. In an experimental rat model of NMO produced by intracerebral injection of AQP4-IgG, Fc hexamers at 50 mg/kg administered before and at 12 h after AQP4-IgG fully prevented astrocyte injury, complement activation, inflammation and demyelination. These results support the potential therapeutic utility of recombinant IgG1 Fc hexamers in AQP4-IgG seropositive NMO. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Human IgG4: a structural perspective.

    Science.gov (United States)

    Davies, Anna M; Sutton, Brian J

    2015-11-01

    IgG4, the least represented human IgG subclass in serum, is an intriguing antibody with unique biological properties, such as the ability to undergo Fab-arm exchange and limit immune complex formation. The lack of effector functions, such as antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity, is desirable for therapeutic purposes. IgG4 plays a protective role in allergy by acting as a blocking antibody, and inhibiting mast cell degranulation, but a deleterious role in malignant melanoma, by impeding IgG1-mediated anti-tumor immunity. These findings highlight the importance of understanding the interaction between IgG4 and Fcγ receptors. Despite a wealth of structural information for the IgG1 subclass, including complexes with Fcγ receptors, and structures for intact antibodies, high-resolution crystal structures were not reported for IgG4-Fc until recently. Here, we highlight some of the biological properties of human IgG4, and review the recent crystal structures of IgG4-Fc. We discuss the unexpected conformations adopted by functionally important Cγ2 domain loops, and speculate about potential implications for the interaction between IgG4 and FcγRs. © 2015 The Authors. Immunological Reviews Published by John Wiley & Sons Ltd.

  4. 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.

  5. IgG receptor FcγRIIB plays a key role in obesity-induced hypertension.

    Science.gov (United States)

    Sundgren, Nathan C; Vongpatanasin, Wanpen; Boggan, Brigid-Meghan D; Tanigaki, Keiji; Yuhanna, Ivan S; Chambliss, Ken L; Mineo, Chieko; Shaul, Philip W

    2015-02-01

    There is a well-recognized association between obesity, inflammation, and hypertension. Why obesity causes hypertension is poorly understood. We previously demonstrated using a C-reactive protein (CRP) transgenic mouse that CRP induces hypertension that is related to NO deficiency. Our prior work in cultured endothelial cells identified the Fcγ receptor IIB (FcγRIIB) as the receptor for CRP whereby it antagonizes endothelial NO synthase. Recognizing known associations between CRP and obesity and hypertension in humans, in the present study we tested the hypothesis that FcγRIIB plays a role in obesity-induced hypertension in mice. Using radiotelemetry, we first demonstrated that the hypertension observed in transgenic mouse-CRP is mediated by the receptor, indicating that FcγRIIB is capable of modifying blood pressure. We then discovered in a model of diet-induced obesity yielding equal adiposity in all study groups that whereas FcγRIIB(+/+) mice developed obesity-induced hypertension, FcγRIIB(-/-) mice were fully protected. Levels of CRP, the related pentraxin serum amyloid P component which is the CRP-equivalent in mice, and total IgG were unaltered by diet-induced obesity; FcγRIIB expression in endothelium was also unchanged. However, whereas IgG isolated from chow-fed mice had no effect, IgG from high-fat diet-fed mice inhibited endothelial NO synthase in cultured endothelial cells, and this was an FcγRIIB-dependent process. Thus, we have identified a novel role for FcγRIIB in the pathogenesis of obesity-induced hypertension, independent of processes regulating adiposity, and it may entail an IgG-induced attenuation of endothelial NO synthase function. Approaches targeting FcγRIIB may potentially offer new means to treat hypertension in obese individuals. © 2014 American Heart Association, Inc.

  6. IgG Receptor FcγRIIB Plays a Key Role in Obesity-Induced Hypertension

    Science.gov (United States)

    Sundgren, Nathan C.; Vongpatanasin, Wanpen; Boggan, Brigid-Meghan D.; Tanigaki, Keiji; Yuhanna, Ivan S.; Chambliss, Ken L.; Mineo, Chieko; Shaul, Philip W.

    2015-01-01

    There is a well-recognized association between obesity, inflammation, and hypertension. Why obesity causes hypertension is poorly understood. We previously demonstrated using a C-reactive protein (CRP) transgenic mouse that CRP induces hypertension that is related to NO deficiency. Our prior work in cultured endothelial cells identified the Fcγ receptor IIB (FcγRIIB) as the receptor for CRP whereby it antagonizes endothelial NO synthase. Recognizing known associations between CRP and obesity and hypertension in humans, in the present study we tested the hypothesis that FcγRIIB plays a role in obesity-induced hypertension in mice. Using radiotelemetry, we first demonstrated that the hypertension observed in transgenic mouse-CRP is mediated by the receptor, indicating that FcγRIIB is capable of modifying blood pressure. We then discovered in a model of diet-induced obesity yielding equal adiposity in all study groups that whereas FcγRIIB+/+ mice developed obesity-induced hypertension, FcγRIIB−/− mice were fully protected. Levels of CRP, the related pentraxin serum amyloid P component which is the CRP-equivalent in mice, and total IgG were unaltered by diet-induced obesity; FcγRIIB expression in endothelium was also unchanged. However, whereas IgG isolated from chow-fed mice had no effect, IgG from high-fat diet–fed mice inhibited endothelial NO synthase in cultured endothelial cells, and this was an FcγRIIB-dependent process. Thus, we have identified a novel role for FcγRIIB in the pathogenesis of obesity-induced hypertension, independent of processes regulating adiposity, and it may entail an IgG-induced attenuation of endothelial NO synthase function. Approaches targeting FcγRIIB may potentially offer new means to treat hypertension in obese individuals. PMID:25368023

  7. A vaccine of L2 epitope repeats fused with a modified IgG1 Fc induced cross-neutralizing antibodies and protective immunity against divergent human papillomavirus types.

    Science.gov (United States)

    Chen, Xue; Liu, Hongyang; Zhang, Ting; Liu, Yanchun; Xie, Xixiu; Wang, Zhirong; Xu, Xuemei

    2014-01-01

    Current human papillomavirus (HPV) major capsid protein L1 virus-like particles (VLPs)-based vaccines in clinic induce strong HPV type-specific neutralizing antibody responses. To develop pan-HPV vaccines, here, we show that the fusion protein E3R4 consisting of three repeats of HPV16 L2 aa 17-36 epitope (E3) and a modified human IgG1 Fc scaffold (R4) induces cross-neutralizing antibodies and protective immunity against divergent HPV types. E3R4 was expressed as a secreted protein in baculovirus expression system and could be simply purified by one step Protein A affinity chromatography with the purity above 90%. Vaccination of E3R4 formulated with Freunds adjuvant not only induced cross-neutralizing antibodies against HPV pseudovirus types 16, 18, 45, 52, 58, 6, 11 and 5 in mice, but also protected mice against vaginal challenges with HPV pseudovirus types 16, 45, 52, 58, 11 and 5 for at least eleven months after the first immunization. Moreover, vaccination of E3R4 formulated with FDA approved adjuvant alum plus monophosphoryl lipid A also induced cross-neutralizing antibodies against HPV types 16, 18 and 6 in rabbits. Thus, our results demonstrate that delivery of L2 antigen as a modified Fc-fusion protein may facilitate pan-HPV vaccine development.

  8. Comparative studies on Fc receptors for IgG on resting and activated T lymphocytes

    International Nuclear Information System (INIS)

    Hueckel, C.; Jensen, H.L.; Rychly, J.; Sandor, M.; Erdei, A.; Gergely, J.

    1986-01-01

    Fc-receptors for IgG (FcγR) on resting (i.e. freshly prepared) and mitogen (Con A) or alloantigen-activated mouse spleen T cells were compared using binding of different markers such as 125 I-labelled immune complexes, 125 I-labelled anti FcγR monoclonal antibody, FITC-labelled aggr. IgG and sheep erythrocytes covered with specific antibody (EA rosetting). C3b receptors were detected by rosetting with sheep erythrocytes covered with antibody and complement (EAC rosetting). The electrophoretic mobility of the cells without or after binding of aggr. IgG was also tested. Differences between resting and activated T cells were found: (1) After activation of T cells by mitogen or alloantigen, a proportion of FcγR-positive cells increased two to four times. (2) FcγR number per FcγR-positive cell seemed to be higher on activated then on resting cells. (3) FcγR-positive resting cells did not shed their FcγR upon incubation at 4 0 C followed by incubation at 37 0 C, but FcγR-positive activated cells shed a remarkable proportion of their FcγR on the same conditions. (4) Binding of aggr. IgG caused a decrease of electrophoretic mobility of activated but not resting cells. (5) FcγR-positive resting cells were also C3b receptor-positive, whereas FcγR-positive activated cells had no detectable C3b receptors. (author)

  9. Generation and Characterization of an IgG4 Monomeric Fc Platform.

    Directory of Open Access Journals (Sweden)

    Lu Shan

    Full Text Available The immunoglobulin Fc region is a homodimer consisted of two sets of CH2 and CH3 domains and has been exploited to generate two-arm protein fusions with high expression yields, simplified purification processes and extended serum half-life. However, attempts to generate one-arm fusion proteins with monomeric Fc, with one set of CH2 and CH3 domains, are often plagued with challenges such as weakened binding to FcRn or partial monomer formation. Here, we demonstrate the generation of a stable IgG4 Fc monomer with a unique combination of mutations at the CH3-CH3 interface using rational design combined with in vitro evolution methodologies. In addition to size-exclusion chromatography and analytical ultracentrifugation, we used multi-angle light scattering (MALS to show that the engineered Fc monomer exhibits excellent monodispersity. Furthermore, crystal structure analysis (PDB ID: 5HVW reveals monomeric properties supported by disrupted interactions at the CH3-CH3 interface. Monomeric Fc fusions with Fab or scFv achieved FcRn binding and serum half-life comparable to wildtype IgG. These results demonstrate that this monomeric IgG4 Fc is a promising therapeutic platform to extend the serum half-life of proteins in a monovalent format.

  10. A Two-pronged Binding Mechanism of IgG to the Neonatal Fc Receptor Controls Complex Stability and IgG Serum Half-life

    DEFF Research Database (Denmark)

    Jensen, Pernille Foged; Schoch, Angela; Larraillet, Vincent

    2017-01-01

    The success of recombinant monoclonal immunoglobulins (IgG) is rooted in their ability to target distinct antigens with high affinity combined with an extraordinarily long serum half-life, typically around 3 weeks. The pharmacokinetics of IgGs is intimately linked to the recycling mechanism...... half-life of ∼8 days. Here we dissect the molecular origins of excessive FcRn binding in therapeutic IgGs using a combination of hydrogen/deuterium exchange mass spectrometry and FcRn affinity chromatography. We provide experimental evidence for a two-pronged IgG-FcRn binding mechanism involving direct...

  11. Transfer of IgG in the female genital tract by MHC class I-related neonatal Fc receptor (FcRn) confers protective immunity to vaginal infection

    Science.gov (United States)

    IgG is a major immunoglobulin subclass in mucosal secretions of human female genital tract, where it predominates over the IgA isotype. Despite the abundance of IgG, surprisingly little is known about whether and how IgG enters the lumen of the genital tract and the exact role of local IgG may play ...

  12. Associations between an IgG3 polymorphism in the binding domain for FcRn, transplacental transfer of malaria-specific IgG3, and protection against Plasmodium falciparum malaria during infancy: A birth cohort study in Benin.

    Directory of Open Access Journals (Sweden)

    Celia Dechavanne

    2017-10-01

    Full Text Available Transplacental transfer of maternal immunoglobulin G (IgG to the fetus helps to protect against malaria and other infections in infancy. Recent studies have emphasized the important role of malaria-specific IgG3 in malaria immunity, and its transfer may reduce the risk of malaria in infancy. Human IgGs are actively transferred across the placenta by binding the neonatal Fc receptor (FcRn expressed within the endosomes of the syncytiotrophoblastic membrane. Histidine at position 435 (H435 provides for optimal Fc-IgG binding. In contrast to other IgG subclasses, IgG3 is highly polymorphic and usually contains an arginine at position 435, which reduces its binding affinity to FcRn in vitro. The reduced binding to FcRn is associated with reduced transplacental transfer and reduced half-life of IgG3 in vivo. Some haplotypes of IgG3 have histidine at position 435. This study examines the hypotheses that the IgG3-H435 variant promotes increased transplacental transfer of malaria-specific antibodies and a prolonged IgG3 half-life in infants and that its presence correlates with protection against clinical malaria during infancy.In Benin, 497 mother-infant pairs were included in a longitudinal birth cohort. Both maternal and cord serum samples were assayed for levels of IgG1 and IgG3 specific for MSP119, MSP2 (both allelic families, 3D7 and FC27, MSP3, GLURP (both regions, R0 and R2, and AMA1 antigens of Plasmodium falciparum. Cord:maternal ratios were calculated. The maternal IgG3 gene was sequenced to identify the IgG3-H435 polymorphism. A multivariate logistic regression was used to examine the association between maternal IgG3-H435 polymorphism and transplacental transfer of IgG3, adjusting for hypergammaglobulinemia, maternal malaria, and infant malaria exposure. Twenty-four percent of Beninese women living in an area highly endemic for malaria had the IgG3-H435 allele (377 women homozygous for the IgG3-R435 allele, 117 women heterozygous for the IgG

  13. Antigen-Specific IgG ameliorates allergic airway inflammation via Fcγ receptor IIB on dendritic cells

    Directory of Open Access Journals (Sweden)

    Karasuyama Hajime

    2011-04-01

    Full Text Available Abstract Background There have been few reports on the role of Fc receptors (FcRs and immunoglobulin G (IgG in asthma. The purpose of this study is to clarify the role of inhibitory FcRs and antigen presenting cells (APCs in pathogenesis of asthma and to evaluate antigen-transporting and presenting capacity by APCs in the tracheobronchial mucosa. Methods In FcγRIIB deficient (KO and C57BL/6 (WT mice, the effects of intratracheal instillation of antigen-specific IgG were analysed using the model with sensitization and airborne challenge with ovalbumin (OVA. Thoracic lymph nodes instilled with fluorescein-conjugated OVA were analysed by fluorescence microscopy. Moreover, we analysed the CD11c+ MHC class II+ cells which intaken fluorescein-conjugated OVA in thoracic lymph nodes by flow cytometry. Also, lung-derived CD11c+ APCs were analysed by flow cytometry. Effects of anti-OVA IgG1 on bone marrow dendritic cells (BMDCs in vitro were also analysed. Moreover, in FcγRIIB KO mice intravenously transplanted dendritic cells (DCs differentiated from BMDCs of WT mice, the effects of intratracheal instillation of anti-OVA IgG were evaluated by bronchoalveolar lavage (BAL. Results In WT mice, total cells and eosinophils in BAL fluid reduced after instillation with anti-OVA IgG1. Anti-OVA IgG1 suppressed airway inflammation in hyperresponsiveness and histology. In addition, the number of the fluorescein-conjugated OVA in CD11c+ MHC class II+ cells of thoracic lymph nodes with anti-OVA IgG1 instillation decreased compared with PBS. Also, MHC class II expression on lung-derived CD11c+ APCs with anti-OVA IgG1 instillation reduced. Moreover, in vitro, we showed that BMDCs with anti-OVA IgG1 significantly decreased the T cell proliferation. Finally, we demonstrated that the lacking effects of anti-OVA IgG1 on airway inflammation on FcγRIIB KO mice were restored with WT-derived BMDCs transplanted intravenously. Conclusion Antigen-specific IgG ameliorates

  14. 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.

  15. Neuron-derived IgG protects dopaminergic neurons from insult by 6-OHDA and activates microglia through the FcγR I and TLR4 pathways.

    Science.gov (United States)

    Zhang, Jie; Niu, Na; Wang, Mingyu; McNutt, Michael A; Zhang, Donghong; Zhang, Baogang; Lu, Shijun; Liu, Yuqing; Liu, Zhihui

    2013-08-01

    Oxidative and immune attacks from the environment or microglia have been implicated in the loss of dopaminergic neurons of Parkinson's disease. The role of IgG which is an important immunologic molecule in the process of Parkinson's disease has been unclear. Evidence suggests that IgG can be produced by neurons in addition to its traditionally recognized source B lymphocytes, but its function in neurons is poorly understood. In this study, extensive expression of neuron-derived IgG was demonstrated in dopaminergic neurons of human and rat mesencephalon. With an in vitro Parkinson's disease model, we found that neuron-derived IgG can improve the survival and reduce apoptosis of dopaminergic neurons induced by 6-hydroxydopamine toxicity, and also depress the release of NO from microglia triggered by 6-hydroxydopamine. Expression of TNF-α and IL-10 in microglia was elevated to protective levels by neuron-derived IgG at a physiologic level via the FcγR I and TLR4 pathways and microglial activation could be attenuated by IgG blocking. All these data suggested that neuron-derived IgG may exert a self-protective function by activating microglia properly, and IgG may be involved in maintaining immunity homeostasis in the central nervous system and serve as an active factor under pathological conditions such as Parkinson's disease. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  16. Correlating the Impact of Well-Defined Oligosaccharide Structures on Physical Stability Profiles of IgG1-Fc Glycoforms.

    Science.gov (United States)

    More, Apurva S; Toprani, Vishal M; Okbazghi, Solomon Z; Kim, Jae H; Joshi, Sangeeta B; Middaugh, C Russell; Tolbert, Thomas J; Volkin, David B

    2016-02-01

    As part of a series of articles in this special issue describing 4 well-defined IgG1-Fc glycoforms as a model system for biosimilarity analysis (high mannose-Fc, Man5-Fc, GlcNAc-Fc and N297Q-Fc aglycosylated), the focus of this work is comparisons of their physical properties. A trend of decreasing apparent solubility (thermodynamic activity) by polyethylene glycol precipitation (pH 4.5, 6.0) and lower conformational stability by differential scanning calorimetry (pH 4.5) was observed with reducing size of the N297-linked oligosaccharide structures. Using multiple high-throughput biophysical techniques, the physical stability of the Fc glycoproteins was then measured in 2 formulations (NaCl and sucrose) across a wide range of temperatures (10°C-90°C) and pH (4.0-7.5) conditions. The data sets were used to construct 3-index empirical phase diagrams and radar charts to visualize the regions of protein structural stability. Each glycoform showed improved stability in the sucrose (vs. salt) formulation. The HM-Fc and Man5-Fc displayed the highest relative stability, followed by GlcNAc-Fc, with N297Q-Fc being the least stable. Thus, the overall physical stability profiles of the 4 IgG1-Fc glycoforms also show a correlation with oligosaccharide structure. These data sets are used to develop a mathematical model for biosimilarity analysis (as described in a companion article by Kim et al. in this issue). Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  17. Radioimmunoassay of IgG and IgM rheumatoid factors reacting with human IgG

    International Nuclear Information System (INIS)

    Carson, D.A.; Lawrance, S.; Catalano, M.A.; Vaughan, J.H.; Abraham, G.

    1977-01-01

    Although IgG rheumatoid factor may play a central role in the pathogenesis of rheumatoid arthritis, previously there have been no precise methods for its specific measurement in serum and synovial fluid. This paper describes a solid phase radioimmunoassay for the independent quantification of IgM and IgG rheumatoid factor reacting with the Fc fragment of human IgG. As measured by this assay, serum IgG rheumatoid factor levels differed significantly between patients with seropositive and seronegative rheumatoid arthritis and normal control subjects. In addition, several sera and joint fluids from patients with seropositive rheumatoid arthritis, even without vasculitis, were shown by gel chromatography to have acid-dissociable complexes of IgG rheumatoid factor suggestive of IgG-IgG dimer or trimer formation

  18. Stability assessment on a library scale: a rapid method for the evaluation of the commutability and insertion of residues in C-terminal loops of the CH3 domains of IgG1-Fc.

    Science.gov (United States)

    Hasenhindl, Christoph; Traxlmayr, Michael W; Wozniak-Knopp, Gordana; Jones, Phil C; Stadlmayr, Gerhard; Rüker, Florian; Obinger, Christian

    2013-10-01

    Antigen-binding Fc fragments (Fcab) are generated by engineering the C-terminal loop regions in the CH3 domain of human immunoglobulin G class 1-crystallizable fragment (IgG1-Fc). For an optimum library design with high percentage of well-folded clones for efficient binder selection, information about the correlation between primary structure and stability is needed. Here, we present a rapid method that allows determination of the overall stability of whole libraries of IgG1-Fc on the surface of yeast by flow cytometry. Libraries of IgG1-Fc mutants with distinct regions in AB-, CD- and EF-loops of the CH3 domains randomized or carrying therein insertions of five additional residues were constructed, incubated at increasing temperatures and probed for residual binding of generic Fc ligands. Calculated temperatures of half-maximal irreversible denaturation of the libraries gave a clear hierarchy of tolerance to randomization of distinct loop positions. Experimental data were evaluated by a computational approach and are discussed with respect to the structure of IgG1-Fc and variation in sequence and length of these loops in homologous Fc proteins. Generally, the described method allows for quick assessment of the effects of randomization of distinct regions on the foldability and stability of a yeast-displayed protein library.

  19. Cutting Edge: The murine high-affinity IgG receptor FcγRIV is sufficient for autoantibody-induced arthritis.

    Science.gov (United States)

    Mancardi, David A; Jönsson, Friederike; Iannascoli, Bruno; Khun, Huot; Van Rooijen, Nico; Huerre, Michel; Daëron, Marc; Bruhns, Pierre

    2011-02-15

    K/BxN serum-induced passive arthritis was reported to depend on the activation of mast cells, triggered by the activating IgG receptor FcγRIIIA, when engaged by IgG1 autoantibodies present in K/BxN serum. This view is challenged by the fact that FcγRIIIA-deficient mice still develop K/BxN arthritis and because FcγRIIIA is the only activating IgG receptor expressed by mast cells. We investigated the contribution of IgG receptors, IgG subclasses, and cells in K/BxN arthritis. We found that the activating IgG2 receptor FcγRIV, expressed only by monocytes/macrophages and neutrophils, was sufficient to induce disease. K/BxN arthritis occurred not only in mast cell-deficient W(sh) mice, but also in mice whose mast cells express no activating IgG receptors. We propose that at least two autoantibody isotypes, IgG1 and IgG2, and two activating IgG receptors, FcγRIIIA and FcγRIV, contribute to K/BxN arthritis, which requires at least two cell types other than mast cells, monocytes/macrophages, and neutrophils.

  20. Natural form of noncytolytic flexible human Fc as a long-acting carrier of agonistic ligand, erythropoietin.

    Directory of Open Access Journals (Sweden)

    Se Jin Im

    Full Text Available Human IgG1 Fc has been widely used as a bioconjugate, but exhibits shortcomings, such as antibody- and complement-mediated cytotoxicity as well as decreased bioactivity, when applied to agonistic proteins. Here, we constructed a nonimmunogenic, noncytolytic and flexible hybrid Fc (hyFc consisting of IgD and IgG4, and tested its function using erythropoietin (EPO conjugate, EPO-hyFc. Despite low amino acid homology (20.5% between IgD Fc and IgG4 Fc, EPO-hyFc retained "Y-shaped" structure and repeated intravenous administrations of EPO-hyFc into monkeys did not generate EPO-hyFc-specific antibody responses. Furthermore, EPO-hyFc could not bind to FcγR I and C1q in contrast to EPO-IgG1 Fc. In addition, EPO-hyFc exhibited better in vitro bioactivity and in vivo bioactivity in rats than EPO-IgG1 Fc, presumably due to the high flexibility of IgD. Moreover, the mean serum half-life of EPO-hyFc(H, a high sialic acid content form of EPO-hyFc, was approximately 2-fold longer than that of the heavily glycosylated EPO, darbepoetin alfa, in rats. More importantly, subcutaneous injection of EPO-hyFc(H not only induced a significantly greater elevation of serum hemoglobin levels than darbepoetin alfa in both normal rats and cisplatin-induced anemic rats, but also displayed a delayed time to maximal serum level and twice final area-under-the-curve (AUC(last. Taken together, hyFc might be a more attractive Fc conjugate for agonistic proteins/peptides than IgG1 Fc due to its capability to elongate their half-lives without inducing host effector functions and hindering bioactivity of fused molecules. Additionally, a head-to-head comparison demonstrated that hyFc-fusion strategy more effectively improved the in vivo bioactivity of EPO than the hyperglycosylation approach.

  1. Natural form of noncytolytic flexible human Fc as a long-acting carrier of agonistic ligand, erythropoietin.

    Science.gov (United States)

    Im, Se Jin; Yang, Sang In; Yang, Se Hwan; Choi, Dong Hoon; Choi, So Young; Kim, Hea Sook; Jang, Do Soo; Jin, Kyeong Sik; Chung, Yo-Kyung; Kim, Seung-Hee; Paik, Sang Hoon; Park, Yoo Chang; Chung, Moon Koo; Kim, Yong Bum; Han, Kang-Hyun; Choi, Kwan Yong; Sung, Young Chul

    2011-01-01

    Human IgG1 Fc has been widely used as a bioconjugate, but exhibits shortcomings, such as antibody- and complement-mediated cytotoxicity as well as decreased bioactivity, when applied to agonistic proteins. Here, we constructed a nonimmunogenic, noncytolytic and flexible hybrid Fc (hyFc) consisting of IgD and IgG4, and tested its function using erythropoietin (EPO) conjugate, EPO-hyFc. Despite low amino acid homology (20.5%) between IgD Fc and IgG4 Fc, EPO-hyFc retained "Y-shaped" structure and repeated intravenous administrations of EPO-hyFc into monkeys did not generate EPO-hyFc-specific antibody responses. Furthermore, EPO-hyFc could not bind to FcγR I and C1q in contrast to EPO-IgG1 Fc. In addition, EPO-hyFc exhibited better in vitro bioactivity and in vivo bioactivity in rats than EPO-IgG1 Fc, presumably due to the high flexibility of IgD. Moreover, the mean serum half-life of EPO-hyFc(H), a high sialic acid content form of EPO-hyFc, was approximately 2-fold longer than that of the heavily glycosylated EPO, darbepoetin alfa, in rats. More importantly, subcutaneous injection of EPO-hyFc(H) not only induced a significantly greater elevation of serum hemoglobin levels than darbepoetin alfa in both normal rats and cisplatin-induced anemic rats, but also displayed a delayed time to maximal serum level and twice final area-under-the-curve (AUC(last)). Taken together, hyFc might be a more attractive Fc conjugate for agonistic proteins/peptides than IgG1 Fc due to its capability to elongate their half-lives without inducing host effector functions and hindering bioactivity of fused molecules. Additionally, a head-to-head comparison demonstrated that hyFc-fusion strategy more effectively improved the in vivo bioactivity of EPO than the hyperglycosylation approach.

  2. Ligand binding and antigenic properties of a human neonatal Fc receptor with mutation of two unpaired cysteine residues

    DEFF Research Database (Denmark)

    Andersen, Jan T; Justesen, Sune; Fleckenstein, Burkhard

    2008-01-01

    knowledge gives incentives for the design of IgG and albumin-based diagnostics and therapeutics. To study FcRn in vitro and to select and characterize FcRn binders, large quantities of soluble human FcRn are needed. In this report, we explored the impact of two free cysteine residues (C48 and C251......) of the FcRn heavy chain on the overall structure and function of soluble human FcRn and described an improved bacterial production strategy based on removal of these residues, yielding approximately 70 mg.L(-1) of fermentation of refolded soluble human FcRn. The structural and functional integrity...... was proved by CD, surface plasmon resonance and MALDI-TOF peptide mapping analyses. The strategy may generally be translated to the large-scale production of other major histocompatibility complex class I-related molecules with nonfunctional unpaired cysteine residues. Furthermore, the anti-FcRn response...

  3. Advances in therapeutic Fc engineering - modulation of IgG associated effector functions and serum half-life

    Directory of Open Access Journals (Sweden)

    Abhishek Saxena

    2016-12-01

    Full Text Available Today monoclonal immunoglobulin gamma (IgG antibodies have become a major option in cancer therapy especially for the patients with advanced or metastatic cancers. Efficacy of monoclonal antibodies (mAbs are achieved through both its antigen binding fragment (Fab and crystallizable fragment (Fc. Fab can specifically recognize tumor associated antigen (TAA and thus modulate TAA-linked downstream signaling pathways that may lead to inhibition of tumor growth, induction of tumor apoptosis and differentiation. The Fc region can further improve mAbs’ efficacy by mediating effector functions such as antibody-dependent cellular cytotoxicity (ADCC, complement-dependent cytotoxicity (CDC and antibody dependent cell-mediated phagocytosis (ADCP. Moreover, Fc is the region interacting with the neonatal Fc receptor (FcRn in a pH-dependent manner that can slow down IgG’s degradation and extend its serum half-life. Loss of the antibody Fc region dramatically shortens its serum half-life and weakens its anti-cancer effects. Given the essential roles that the Fc region plays in the modulation of the efficacy of mAb in cancer treatment, Fc engineering has been extensively studied in the past years. This review focuses on the recent advances in therapeutic Fc engineering that modulates its related effector functions and serum half-life. We also discuss the progress made in aglycosylated mAb development that may substantially reduce cost of manufacture but maintain similar efficacies as conventional glycosylated mAb. Finally, we highlight several Fc engineering based mAbs under clinical trials.

  4. Correlation of Fc(gamma)RIIa (CD32) Polymorphism and IgG Antibody Subclasses in Hemolytic Disease of Newborn.

    Science.gov (United States)

    Wu, QiangJu; Zhang, Yan; Liu, MengLi; Wang, Bo; Liu, Sheng; He, Chen

    2009-01-01

    ABO-HDN is a common disease of newborn in China and currently there is no satisfactory method to predict it in the antepartum period. It has been reported that Fc(gamma)RIIa (CD32) genotype is associated with both infectious diseases induced by bacteria and parasitemia. There is a relationship between IgG subclass and RH-HDN. To study the pathogenesis of ABO-HDN and to find reliable method to diagnose ABO-HDN, we investigated the polymorphism of Fc(gamma)RIIa (CD32) and distribution of IgG subclass in infants with ABO-HDN and their mothers by polymerase chain reaction or ELISA assay. We observed that the frequency of HH131 genotype is lower in infants with ABO-HDN than in controls (p < 0.01), while the frequency of HR131 genotype is higher in ABO-HDN infants than that in controls (p < 0.01). The genotype HR131 and concentrations of IgG1 and IgG3 are significantly correlated with ABO-HDN. Our results demonstrated, for the first time, that there is a correlation between ABO-HDN and CD32, and different IgG subclass distribution. Our study may contribute to the development of an early diagnostic method for HDN. Copyright 2009 S. Karger AG, Basel.

  5. Oriented immobilized anti-hIgG via F(c) fragment-imprinted PHEMA cryogel for IgG purification.

    Science.gov (United States)

    Bereli, Nilay; Ertürk, Gizem; Tümer, M Aşkin; Say, Ridvan; Denizli, Adil

    2013-05-01

    Antibodies are used in many applications, especially as diagnostic and therapeutic agents. Among the various techniques used for the purification of antibodies, immunoaffinity chromatography is by far the most common. For this purpose, oriented immobilization of antibodies is an important step for the efficiency of purification step. In this study, F(c) fragment-imprinted poly(hydroxyethyl methacrylate) cryogel (MIP) was prepared for the oriented immobilization of anti-hIgG for IgG purification from human plasma. Non-imprinted poly(hydroxyethyl methacrylate) cryogel (NIP) was also prepared for random immobilization of anti-hIgG to compare the adsorption capacities of oriented (MIP/anti-hIgG) and random (NIP/anti-hIgG) cryogel columns. The amount of immobilized anti-hIgG was 19.8 mg/g for the NIP column and 23.7 mg/g for the MIP column. Although the amount of immobilized anti-hIgG was almost the same for the NIP and MIP columns, IgG adsorption capacity was found to be three times higher than the NIP/anti-hIgG column (29.7 mg/g) for the MIP/anti-hIgG column (86.9 mg/g). Higher IgG adsorption capacity was observed from human plasma (up to 106.4 mg/g) with the MIP/anti-hIgG cryogel column. Adsorbed IgG was eluted using 1.0 M NaCl with a purity of 96.7%. The results obtained here are very encouraging and showed the usability of MIP/anti-hIgG cryogel prepared via imprinting of Fc fragments as an alternative to conventional immunoaffinity techniques for IgG purification. Copyright © 2012 John Wiley & Sons, Ltd.

  6. A strategy for bacterial production of a soluble functional human neonatal Fc receptor

    DEFF Research Database (Denmark)

    Andersen, Jan Terje; Justesen, Sune; Berntzen, Gøril

    2008-01-01

    The major histocompatibility complex (MHC) class I related receptor, the neonatal Fc receptor (FcRn), rescues immunoglobulin G (IgG) and albumin from lysosomal degradation by recycling in endothelial cells. FcRn also contributes to passive immunity by mediating transport of IgG from mother to fetus...

  7. Fcγ1 fragment of IgG1 as a powerful affinity tag in recombinant Fc-fusion proteins: immunological, biochemical and therapeutic properties.

    Science.gov (United States)

    Soleimanpour, Saman; Hassannia, Tahereh; Motiee, Mahdieh; Amini, Abbas Ali; Rezaee, S A R

    2017-05-01

    Affinity tags are vital tools for the production of high-throughput recombinant proteins. Several affinity tags, such as the hexahistidine tag, maltose-binding protein, streptavidin-binding peptide tag, calmodulin-binding peptide, c-Myc tag, glutathione S-transferase and FLAG tag, have been introduced for recombinant protein production. The fragment crystallizable (Fc) domain of the IgG1 antibody is one of the useful affinity tags that can facilitate detection, purification and localization of proteins and can improve the immunogenicity, modulatory effects, physicochemical and pharmaceutical properties of proteins. Fcγ recombinant forms a group of recombinant proteins called Fc-fusion proteins (FFPs). FFPs are widely used in drug discovery, drug delivery, vaccine design and experimental research on receptor-ligand interactions. These fusion proteins have become successful alternatives to monoclonal antibodies for drug developments. In this review, the physicochemical, biochemical, immunological, pharmaceutical and therapeutic properties of recombinant FFPs were discussed as a new generation of bioengineering strategies.

  8. Quantitative glycan profiling of normal human plasma derived immunoglobulin and its fragments Fab and Fc.

    Science.gov (United States)

    Anumula, Kalyan Rao

    2012-08-31

    Typical clinical grade human IgG (intravenous immunoglobulin, IVIG), used for carbohydrate analysis, is derived from thousands of healthy donors. Quantitative high-resolution glycan profiles of IgG and its Fc-Fab fragments are presented here. Glycan profiles were established following digestions with Fc specific endoglycosidase S and generic PNGase F under denaturing and non-denaturing (native) conditions. The native PNGase F glycan profile of IgG was similar (but not identical) to that of Endo S. Endo S profiles did not contain the glycans with bisecting GlcNAc. PNGase F glycan profiles were the same for Fc fragments that were isolated from pepsin and Ide S protease digests. Both isolated Fab fragments and the previously deglycosylated IVIG (native conditions) yielded the same glycan profile. Glycan profiles were established using high resolution HPLC with 2-aminobenzoic acid (2AA) labeling. An accurate determination of sialylation levels can be made by this method. Carbohydrate content in Fc and Fab was determined using an internal standard and corrected for both protein and glycan recoveries. Fab portion contained about 14% of the total carbohydrate which translates to 2.3 sugar chains per mol in IVIG where 2 chains are located in the CH2 domain of the Fc. Fc glycans consisted of neutral (N) 84.5%; mono-sialylated (S1) 15% and di-sialylated (S2) 0.5%. In contrast, Fab contained N, 21%; S1, 43% and S2, 36%. The distribution of bisecting N-acetylglucosamine and fucose was found to be very different in various glycans (N, S1 and S2) found in Fab and Fc. Total IgG glycan profile (Fab plus Fc) contained N, 78.5%; S1, 17% and S2, 4.5%. Percent distribution of glycans G0, G1 and G2 (with 0, 1 and 2 two galactoses) was 26, 49 and 25 respectively within the 78% of the neutral glycans. Glycan profiles were nearly the same for various clinical grade IVIG preparations from various manufacturers. A fast HPLC profiling method was developed for the separation and quantitation

  9. Low-affinity FcγR interactions can decide the fate of novel human IgG-sensitised red blood cells and platelets

    Science.gov (United States)

    Armour, Kathryn L; Smith, Cheryl S; Turner, Craig P; Kirton, Christopher M; Wilkes, Anthony M; Hadley, Andrew G; Ghevaert, Cedric; Williamson, Lorna M; Clark, Michael R

    2014-01-01

    G1Δnab is a mutant human IgG1 constant region with a lower ability to interact with FcγR than the natural IgG constant regions. Radiolabelled RBCs and platelets sensitised with specific G1Δnab Abs were cleared more slowly from human circulation than IgG1-sensitised counterparts. However, non-destructive splenic retention of G1Δnab-coated RBCs required investigation and plasma radioactivities now suggest this also occurred for platelets sensitised with an IgG1/G1Δnab mixture. In vitro assays with human cells showed that G1Δnab-sensitised RBCs did not cause FcγRI-mediated monocyte activation, FcγRIIIa-mediated antibody-dependent cell-mediated cytotoxicity (ADCC) or macrophage phagocytosis although they did adhere to macrophages. Thus, FcγRII was implicated in the adhesion despite the Δnab mutation reducing the already low-affinity binding to this receptor class. Additional contacts via P-selectin enhance the interaction of sensitised platelets with monocytes and this system provided evidence of FcγRII-dependent activation by G1Δnab. These results emphasise the physiological relevance of low-affinity interactions: It appears that FcγRII interactions of G1Δnab allowed splenic retention of G1Δnab-coated RBCs with inhibitory FcγRIIb binding preventing RBC destruction and that FcγRIIb engagement by G1Δnab on IgG1/G1Δnab-sensitised platelets overcame activation by IgG1. Considering therapeutic blocking Abs, G1Δnab offers lower FcγR binding and a greater bias towards inhibition than IgG2 and IgG4 constant regions. PMID:24285214

  10. Sudan ebolavirus long recovered survivors produce GP-specific Abs that are of the IgG1 subclass and preferentially bind FcγRI.

    Science.gov (United States)

    Radinsky, Olga; Edri, Avishay; Brusilovsky, Michael; Fedida-Metula, Shlomit; Sobarzo, Ariel; Gershoni-Yahalom, Orly; Lutwama, Julius; Dye, John; Lobel, Leslie; Porgador, Angel

    2017-07-20

    Ebolavirus is a highly lethal pathogen, causing a severe hemorrhagic disease with a high fatality rate. To better understand immune correlates of protection by virus specific IgG, we investigated the evolution of the Fcγ receptors (FcγRs)-activating capabilities of antiviral IgG in serum samples of long recovered survivors. To this end, longitudinal serum samples from survivors of Sudan ebolavirus (SUDV) infection, studied over years, were examined for the presence of Ebola-GP specific IgG subclasses, and for their binding to FcγRs. We developed a cell-based reporter system to quantitate pathogen-specific antibody binding to FcγRIIIA, FcγRIIA, FcγRIIB and FcγRI. With this system, we demonstrate that anti-GP-specific stimulation of the FcγRI reporter by survivors' sera was substantially high one year after acute infection, with a slight reduction in activity over a decade post infection. We further demonstrate that GP-specific IgG1 is by far the seroprevalent subclass that retained and even enhanced its presence in the sera, over ten years post infection; the prevalence of other GP-specific IgG subclasses was considerably reduced over time. In accordance, GP-specific FcγRI reporter response and GP-specific total IgG1 subclass correlated in the studied group of Ebola survivors. These observations are important for further informing Ebola vaccine and therapeutic development.

  11. Specificity and Effector Functions of Human RSV-Specific IgG from Bovine Milk.

    Directory of Open Access Journals (Sweden)

    Gerco den Hartog

    Full Text Available Respiratory syncytial virus (RSV infection is the second most important cause of death in the first year of life, and early RSV infections are associated with the development of asthma. Breastfeeding and serum IgG have been shown to protect against RSV infection. Yet, many infants depend on bovine milk-based nutrition, which at present lacks intact immunoglobulins.To investigate whether IgG purified from bovine milk (bIgG can modulate immune responses against human RSV.ELISAs were performed to analyse binding of bIgG to human respiratory pathogens. bIgG or hRSV was coated to plates to assess dose-dependent binding of bIgG to human Fcγ receptors (FcγR or bIgG-mediated binding of myeloid cells to hRSV respectively. S. Epidermidis and RSV were used to test bIgG-mediated binding and internalisation of pathogens by myeloid cells. Finally, the ability of bIgG to neutralise infection of HEp2 cells by hRSV was evaluated.bIgG recognised human RSV, influenza haemagglutinin and Haemophilus influenza. bIgG bound to FcγRII on neutrophils, monocytes and macrophages, but not to FcγRI and FcγRIII, and could bind simultaneously to hRSV and human FcγRII on neutrophils. In addition, human neutrophils and dendritic cells internalised pathogens that were opsonised with bIgG. Finally, bIgG could prevent infection of HEp2 cells by hRSV.The data presented here show that bIgG binds to hRSV and other human respiratory pathogens and induces effector functions through binding to human FcγRII on phagocytes. Thus bovine IgG may contribute to immune protection against RSV.

  12. Specificity and Effector Functions of Human RSV-Specific IgG from Bovine Milk.

    Science.gov (United States)

    den Hartog, Gerco; Jacobino, Shamir; Bont, Louis; Cox, Linda; Ulfman, Laurien H; Leusen, Jeanette H W; van Neerven, R J Joost

    2014-01-01

    Respiratory syncytial virus (RSV) infection is the second most important cause of death in the first year of life, and early RSV infections are associated with the development of asthma. Breastfeeding and serum IgG have been shown to protect against RSV infection. Yet, many infants depend on bovine milk-based nutrition, which at present lacks intact immunoglobulins. To investigate whether IgG purified from bovine milk (bIgG) can modulate immune responses against human RSV. ELISAs were performed to analyse binding of bIgG to human respiratory pathogens. bIgG or hRSV was coated to plates to assess dose-dependent binding of bIgG to human Fcγ receptors (FcγR) or bIgG-mediated binding of myeloid cells to hRSV respectively. S. Epidermidis and RSV were used to test bIgG-mediated binding and internalisation of pathogens by myeloid cells. Finally, the ability of bIgG to neutralise infection of HEp2 cells by hRSV was evaluated. bIgG recognised human RSV, influenza haemagglutinin and Haemophilus influenza. bIgG bound to FcγRII on neutrophils, monocytes and macrophages, but not to FcγRI and FcγRIII, and could bind simultaneously to hRSV and human FcγRII on neutrophils. In addition, human neutrophils and dendritic cells internalised pathogens that were opsonised with bIgG. Finally, bIgG could prevent infection of HEp2 cells by hRSV. The data presented here show that bIgG binds to hRSV and other human respiratory pathogens and induces effector functions through binding to human FcγRII on phagocytes. Thus bovine IgG may contribute to immune protection against RSV.

  13. Physical stability comparisons of IgG1-Fc variants: effects of N-glycosylation site occupancy and Asp/Gln residues at site Asn 297.

    Science.gov (United States)

    Alsenaidy, Mohammad A; Okbazghi, Solomon Z; Kim, Jae Hyun; Joshi, Sangeeta B; Middaugh, C Russell; Tolbert, Thomas J; Volkin, David B

    2014-06-01

    The structural integrity and conformational stability of various IgG1-Fc proteins produced from the yeast Pichia pastoris with different glycosylation site occupancy (di-, mono-, and nonglycosylated) were determined. In addition, the physical stability profiles of three different forms of nonglycosylated Fc molecules (varying amino-acid residues at site 297 in the CH 2 domain due to the point mutations and enzymatic digestion of the Fc glycoforms) were also examined. The physical stability of these IgG1-Fc glycoproteins was examined as a function of pH and temperature by high-throughput biophysical analysis using multiple techniques combined with data visualization tools (three index empirical phase diagrams and radar charts). Across the pH range of 4.0-6.0, the di- and monoglycosylated forms of the IgG1-Fc showed the highest and lowest levels of physical stability, respectively, with the nonglycosylated forms showing intermediate stability depending on solution pH. In the aglycosylated Fc proteins, the introduction of Asp (D) residues at site 297 (QQ vs. DN vs. DD forms) resulted in more subtle changes in structural integrity and physical stability depending on solution pH. The utility of evaluating the conformational stability profile differences between the various IgG1-Fc glycoproteins is discussed in the context of analytical comparability studies. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  14. Processing of complex N-glycans in IgG Fc-region is affected by core fucosylation

    Science.gov (United States)

    Castilho, Alexandra; Gruber, Clemens; Thader, Andreas; Oostenbrink, Chris; Pechlaner, Maria; Steinkellner, Herta; Altmann, Friedrich

    2015-01-01

    We investigated N-glycan processing of immunoglobulin G1 using the monoclonal antibody cetuximab (CxMab), which has a glycosite in the Fab domain in addition to the conserved Fc glycosylation, as a reporter. Three GlcNAc (Gn) terminating bi-antennary glycoforms of CxMab differing in core fucosylation (α1,3- and α1,6-linkage) were generated in a plant-based expression platform. These GnGn, GnGnF3, and GnGnF6 CxMab variants were subjected in vivo to further processing toward sialylation and GlcNAc diversification (bisected and branching structures). Mass spectrometry-based glycan analyses revealed efficient processing of Fab glycans toward envisaged structures. By contrast, Fc glycan processing largely depend on the presence of core fucose. A particularly strong support of glycan processing in the presence of plant-specific core α1,3-fucose was observed. Consistently, molecular modeling suggests changes in the interactions of the Fc carbohydrate chain depending on the presence of core fucose, possibly changing the accessibility. Here, we provide data that reveal molecular mechanisms of glycan processing of IgG antibodies, which may have implications for the generation of glycan-engineered therapeutic antibodies with improved efficacies. PMID:26067753

  15. Clearance of Human IgG1-Sensitised Red Blood Cells In Vivo in Humans Relates to the In Vitro Properties of Antibodies from Alternative Cell Lines

    Science.gov (United States)

    Armour, Kathryn L.; Smith, Cheryl S.; Ip, Natasha C. Y.; Ellison, Cara J.; Kirton, Christopher M.; Wilkes, Anthony M.; Williamson, Lorna M.; Clark, Michael R.

    2014-01-01

    We previously produced a recombinant version of the human anti-RhD antibody Fog-1 in the rat myeloma cell line, YB2/0. When human, autologous RhD-positive red blood cells (RBC) were sensitised with this IgG1 antibody and re-injected, they were cleared much more rapidly from the circulation than had been seen earlier with the original human-mouse heterohybridoma-produced Fog-1. Since the IgG have the same amino acid sequence, this disparity is likely to be due to alternative glycosylation that results from the rat and mouse cell lines. By comparing the in vitro properties of YB2/0-produced Fog-1 IgG1 and the same antibody produced in the mouse myeloma cell line NS0, we now have a unique opportunity to pinpoint the cause of the difference in ability to clear RBC in vivo. Using transfected cell lines that express single human FcγR, we showed that IgG1 made in YB2/0 and NS0 cell lines bound equally well to receptors of the FcγRI and FcγRII classes but that the YB2/0 antibody was superior in FcγRIII binding. When measuring complexed IgG binding, the difference was 45-fold for FcγRIIIa 158F, 20-fold for FcγRIIIa 158V and approximately 40-fold for FcγRIIIb. The dissimilarity was greater at 100-fold in monomeric IgG binding assays with FcγRIIIa. When used to sensitise RBC, the YB2/0 IgG1 generated 100-fold greater human NK cell antibody-dependent cell-mediated cytotoxicity and had a 103-fold advantage over the NS0 antibody in activating NK cells, as detected by CD54 levels. In assays of monocyte activation and macrophage adherence/phagocytosis, where FcγRI plays major roles, RBC sensitised with the two antibodies produced much more similar results. Thus, the alternative glycosylation profiles of the Fog-1 antibodies affect only FcγRIII binding and FcγRIII-mediated functions. Relating this to the in vivo studies confirms the importance of FcγRIII in RBC clearance. PMID:25302805

  16. Clearance of human IgG1-sensitised red blood cells in vivo in humans relates to the in vitro properties of antibodies from alternative cell lines.

    Directory of Open Access Journals (Sweden)

    Kathryn L Armour

    Full Text Available We previously produced a recombinant version of the human anti-RhD antibody Fog-1 in the rat myeloma cell line, YB2/0. When human, autologous RhD-positive red blood cells (RBC were sensitised with this IgG1 antibody and re-injected, they were cleared much more rapidly from the circulation than had been seen earlier with the original human-mouse heterohybridoma-produced Fog-1. Since the IgG have the same amino acid sequence, this disparity is likely to be due to alternative glycosylation that results from the rat and mouse cell lines. By comparing the in vitro properties of YB2/0-produced Fog-1 IgG1 and the same antibody produced in the mouse myeloma cell line NS0, we now have a unique opportunity to pinpoint the cause of the difference in ability to clear RBC in vivo. Using transfected cell lines that express single human FcγR, we showed that IgG1 made in YB2/0 and NS0 cell lines bound equally well to receptors of the FcγRI and FcγRII classes but that the YB2/0 antibody was superior in FcγRIII binding. When measuring complexed IgG binding, the difference was 45-fold for FcγRIIIa 158F, 20-fold for FcγRIIIa 158V and approximately 40-fold for FcγRIIIb. The dissimilarity was greater at 100-fold in monomeric IgG binding assays with FcγRIIIa. When used to sensitise RBC, the YB2/0 IgG1 generated 100-fold greater human NK cell antibody-dependent cell-mediated cytotoxicity and had a 103-fold advantage over the NS0 antibody in activating NK cells, as detected by CD54 levels. In assays of monocyte activation and macrophage adherence/phagocytosis, where FcγRI plays major roles, RBC sensitised with the two antibodies produced much more similar results. Thus, the alternative glycosylation profiles of the Fog-1 antibodies affect only FcγRIII binding and FcγRIII-mediated functions. Relating this to the in vivo studies confirms the importance of FcγRIII in RBC clearance.

  17. Effect of pH, temperature, and salt on the stability of Escherichia coli- and Chinese hamster ovary cell-derived IgG1 Fc.

    Science.gov (United States)

    Li, Cynthia H; Narhi, Linda O; Wen, Jie; Dimitrova, Mariana; Wen, Zai-qing; Li, Jenny; Pollastrini, Joseph; Nguyen, Xichdao; Tsuruda, Trace; Jiang, Yijia

    2012-12-18

    The circulation half-life of a potential therapeutic can be increased by fusing the molecule of interest (an active peptide, the extracellular domain of a receptor, an enzyme, etc.) to the Fc fragment of a monoclonal antibody. For the fusion protein to be a successful therapeutic, it must be stable to process and long-term storage conditions, as well as to physiological conditions. The stability of the Fc used is critical for obtaining a successful therapeutic protein. The effects of pH, temperature, and salt on the stabilities of Escherichia coli- and Chinese hamster ovary cell (CHO)-derived IgG1 Fc high-order structure were probed using a variety of biophysical techniques. Fc molecules derived from both E. coli and CHO were compared. The IgG1 Fc molecules from both sources (glycosylated and aglycosylated) are folded at neutral pH and behave similarly upon heat- and low pH-induced unfolding. The unfolding of both IgG1 Fc molecules occurs via a multistep unfolding process, with the tertiary structure and C(H)2 domain unfolding first, followed by changes in the secondary structure and C(H)3 domain. The acid-induced unfolding of IgG1 Fc molecules is only partially reversible, with the formation of high-molecular weight species. The CHO-derived Fc protein (glycosylated) is more compact (smaller hydrodynamic radius) than the E. coli-derived protein (aglycosylated) at neutral pH. Unfolding is dependent on pH and salt concentration. The glycosylated C(H)2 domain melts at a temperature 4-5 °C higher than that of the aglycosylated domain, and the low-pH-induced unfolding of the glycosylated Fc molecule occurs at a pH ~0.5 pH unit lower than that of the aglycosylated protein. The difference observed between E. coli- and CHO-derived Fc molecules primarily involves the C(H)2 domain, where the glycosylation of the Fc resides.

  18. A simple solid-phase radioimmunoassay for the measurement of IgG secreted in vitro by human lymphocytes

    International Nuclear Information System (INIS)

    Romagnani, S.; Prete, G.F. del; Giudizi, G.M.; Almerigogna, F.; Ricci, M.

    1979-01-01

    A radioimmunoassay is described for measuring IgG, based on the ability of immunoglobulins of this class to inhibit the binding of radioiodinated staphylococcal protein A to IgG linked to a solid phase. The solid phase is represented by ox erythrocytes coated with anti-ox erthrocyte rabbit IgG, a reagent used for detecting cells equipped with receptors for the Fc fragment of IgG. By this assay the IgG secreted in vitro by human peripheral blood lymphocytes stimulated with PWM and those present in samples of very diluted human sera were measured. It was found that the assay is a very rapid, simple and and reproducible procedure for the detection of IgG immunoglobulin at the nanogram level. (Auth.)

  19. Analytical FcRn affinity chromatography for functional characterization of monoclonal antibodies

    Science.gov (United States)

    Schlothauer, Tilman; Rueger, Petra; Stracke, Jan Olaf; Hertenberger, Hubert; Fingas, Felix; Kling, Lothar; Emrich, Thomas; Drabner, Georg; Seeber, Stefan; Auer, Johannes; Koch, Stefan; Papadimitriou, Apollon

    2013-01-01

    The neonatal Fc receptor (FcRn) is important for the metabolic fate of IgG antibodies in vivo. Analysis of the interaction between FcRn and IgG in vitro might provide insight into the structural and functional integrity of therapeutic IgG that may affect pharmacokinetics (PK) in vivo. We developed a standardized pH gradient FcRn affinity liquid chromatography method with conditions closely resembling the physiological mechanism of interaction between IgG and FcRn. This method allows the separation of molecular IgG isoforms, degradation products and engineered molecules based on their affinity to FcRn. Human FcRn was immobilized on the column and a linear pH gradient from pH 5.5 to 8.8 was applied. FcRn chromatography was used in comparison to surface plasmon resonance to characterize different monoclonal IgG preparations, e.g., oxidized or aggregated species. Wild-type and engineered IgGs were compared in vitro by FcRn chromatography and in vivo by PK studies in huFcRn transgenic mice. Analytical FcRn chromatography allows differentiation of IgG samples and variants by peak pattern and retention time profile. The method can distinguish: 1) IgGs with different Fabs, 2) oxidized from native IgG, 3) aggregates from monomer and 4) antibodies with mutations in the Fc part from wild-type IgGs. Changes in the FcRn chromatographic behavior of mutant IgGs relative to the wild-type IgG correlate to changes in the PK profile in the FcRn transgenic mice. These results demonstrate that FcRn affinity chromatography is a useful new method for the assessment of IgG integrity. PMID:23765230

  20. Clearance of red cells by monoclonal IgG3 anti-D in vivo is affected by the VF polymorphism of Fc gamma RIIIa (CD16)

    NARCIS (Netherlands)

    Kumpel, BM; De Haas, M; Koene, HR; Van de Winkel, JGJ; Goodrick, MJ

    Human red cells (RBC) coated with IgG anti-D are cleared from the circulation to the spleen by macrophages which express IgG receptors (Fcgamma R). Polymorphisms of Fcgamma RIIa and Fcgamma RIIIa affect IgG binding in vitro , and may alter the efficiency of clearance of immune complexes in vivo. In

  1. Viral control in chronic HIV-1 subtype C infection is associated with enrichment of p24 IgG1 with Fc effector activity.

    Science.gov (United States)

    Chung, Amy; Makuba, Jenniffer M; Ndlovu, Bongiwe; Licht, Anna; Robinson, Hannah; Ramlakhan, Yathisha; Ghebremichael, Musie; Reddy, Tarylee; Goulder, Philip; Walker, Bruce; Ndung'u, Thumbi; Alter, Galit

    2018-04-03

    Postinfection HIV viral control and immune correlates analysis of the RV144 vaccine trial indicate a potentially critical role for Fc receptor-mediated antibody functions. However, the influence of functional antibodies in clade C infection is largely unknown. Plasma samples from 361 chronic subtype C-infected, antiretroviral therapy-naïve participants were tested for their HIV-specific isotype and subclass distributions, along with their Fc receptor-mediated functional potential. Total IgG, IgG subclasses and IgA binding to p24 clade B/C and gp120 consensus C proteins were assayed by multiplex. Antibody-dependent uptake of antigen-coated beads and Fc receptor-mediated natural killer cell degranulation were evaluated as surrogates for antibody-dependent cellular phagocytosis (ADCP) and antibody-dependent cellular cytotoxicity (ADCC), respectively. p24 IgG1 was the only subclass associated with viral control (P = 0.01), with higher p24-specific ADCP and ADCC responses detected in individuals with high p24 IgG1. Although p24 IgG1 levels were enriched in patients with elevated Gag-specific T-cell responses, these levels remained an independent predictor of low-viral loads (P = 0.04) and high CD4 counts (P = 0.004) after adjusting for Gag-specific T-cell responses and for protective HLA class I alleles. p24 IgG1 levels independently predict viral control in HIV-1 clade C infection. Whether these responses contribute to direct antiviral control via the recruited killing of infected cells via the innate immune system or simply mark a qualitatively superior immune response to HIV, is uncertain, but highlights the role of p24-specific antibodies in control of clade C HIV-1 infection.

  2. Usefulness of FC-TRIPLEX Chagas/Leish IgG1 as confirmatory assay for non-negative results in blood bank screening of Chagas disease.

    Science.gov (United States)

    Campos, Fernanda Magalhães Freire; Repoles, Laura Cotta; de Araújo, Fernanda Fortes; Peruhype-Magalhães, Vanessa; Xavier, Marcelo Antônio Pascoal; Sabino, Ester Cerdeira; de Freitas Carneiro Proietti, Anna Bárbara; Andrade, Mariléia Chaves; Teixeira-Carvalho, Andréa; Martins-Filho, Olindo Assis; Gontijo, Célia Maria Ferreira

    2018-04-01

    A relevant issue in Chagas disease serological diagnosis regards the requirement of using several confirmatory methods to elucidate the status of non-negative results from blood bank screening. The development of a single reliable method may potentially contribute to distinguish true and false positive results. Our aim was to evaluate the performance of the multiplexed flow-cytometry anti-T. cruzi/Leishmania IgG1 serology/(FC-TRIPLEX Chagas/Leish IgG1) with three conventional confirmatory criteria (ELISA-EIA, Immunofluorescence assay-IIF and EIA/IIF consensus criterion) to define the final status of samples with actual/previous non-negative results during anti-T. cruzi ELISA-screening in blood banks. Apart from inconclusive results, the FC-TRIPLEX presented a weak agreement index with EIA, while a strong agreement was observed when either IIF or EIA/IIF consensus criteria were applied. Discriminant analysis and Spearman's correlation further corroborates the agreement scores. ROC curve analysis showed that FC-TRIPLEX performance indexes were higher when IIF and EIA/IIF consensus were used as a confirmatory criterion. Logistic regression analysis further demonstrated that the probability of FC-TRIPLEX to yield positive results was higher for inconclusive results from IIF and EIA/IIF consensus. Machine learning tools illustrated the high level of categorical agreement between FC-TRIPLEX versus IIF or EIA/IIF consensus. Together, these findings demonstrated the usefulness of FC-TRIPLEX as a tool to elucidate the status of non-negative results in blood bank screening of Chagas disease. Copyright © 2018. Published by Elsevier B.V.

  3. Mechanisms of anaphylaxis in human low-affinity IgG receptor locus knock-in mice.

    Science.gov (United States)

    Gillis, Caitlin M; Jönsson, Friederike; Mancardi, David A; Tu, Naxin; Beutier, Héloïse; Van Rooijen, Nico; Macdonald, Lynn E; Murphy, Andrew J; Bruhns, Pierre

    2017-04-01

    Anaphylaxis can proceed through distinct IgE- or IgG-dependent pathways, which have been investigated in various mouse models. We developed a novel mouse strain in which the human low-affinity IgG receptor locus, comprising both activating (hFcγRIIA, hFcγRIIIA, and hFcγRIIIB) and inhibitory (hFcγRIIB) hFcγR genes, has been inserted into the equivalent murine locus, corresponding to a locus swap. We sought to determine the capabilities of hFcγRs to induce systemic anaphylaxis and identify the cell types and mediators involved. hFcγR expression on mouse and human cells was compared to validate the model. Passive systemic anaphylaxis was induced by injection of heat-aggregated human intravenous immunoglobulin and active systemic anaphylaxis after immunization and challenge. Anaphylaxis severity was evaluated based on hypothermia and mortality. The contribution of receptors, mediators, or cell types was assessed based on receptor blockade or depletion. The human-to-mouse low-affinity FcγR locus swap engendered hFcγRIIA/IIB/IIIA/IIIB expression in mice comparable with that seen in human subjects. Knock-in mice were susceptible to passive and active anaphylaxis, accompanied by downregulation of both activating and inhibitory hFcγR expression on specific myeloid cells. The contribution of hFcγRIIA was predominant. Depletion of neutrophils protected against hypothermia and mortality. Basophils contributed to a lesser extent. Anaphylaxis was inhibited by platelet-activating factor receptor or histamine receptor 1 blockade. Low-affinity FcγR locus-switched mice represent an unprecedented model of cognate hFcγR expression. Importantly, IgG-related anaphylaxis proceeds within a native context of activating and inhibitory hFcγRs, indicating that, despite robust hFcγRIIB expression, activating signals can dominate to initiate a severe anaphylactic reaction. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights

  4. Role of polymorphic Fc receptor Fc gammaRIIa in cytokine release and adverse effects of murine IgG1 anti-CD3/T cell receptor antibody (WT31).

    Science.gov (United States)

    Tax, W J; Tamboer, W P; Jacobs, C W; Frenken, L A; Koene, R A

    1997-01-15

    Anti-CD3 monoclonal antibody (mAb) OKT3 is immunosuppressive, but causes severe adverse effects during the first administration ("first-dose reaction"). These adverse effects are presumably caused by cytokine release that results from T-cell activation. In vitro, T-cell activation by anti-CD3 mAb requires interaction with monocyte Fc receptors. The Fc receptor for murine IgG1, Fc gammaRIIa, is polymorphic. In some individuals, murine IgG1 anti-CD3 mAb causes T-cell proliferation and cytokine release in vitro (high responders [HR]), whereas in individuals with the low-responder (LR) phenotype it does not. We have now investigated the role of this Fc gammaRIIa polymorphism in the release of cytokines in vivo and the occurrence of adverse effects after the administration of WT31, a murine IgG1 anti-CD3/T cell receptor mAb. WT31 caused an increase of plasma tumor necrosis factor-alpha in all four HR patients and none of the five LR patients. In all HR patients except one, plasma gamma-interferon and interleukin 6 also increased, and a first-dose response was observed, whereas no cytokine release or adverse effects occurred in any of the LR patients. WT31 caused lymphopenia in all HR and none of the LR patients. FACS analysis demonstrated that in HR patients, after the initial disappearance of CD3+ cells from peripheral blood, modulation of CD3 occurred, whereas in LR patients a high degree of coating of the lymphocytes was observed. Surprisingly, WT31 also induced a marked granulocytopenia, as well as a decrease of thrombocytes, in three of the four HR patients (and in none of the LR patients). These data provide direct clinical evidence that Fc receptor interaction determines the release of cytokines and the occurrence of adverse effects after administration of anti-CD3/T cell receptor mAb. Furthermore, these data suggest that tumor necrosis factor-alpha by itself is not sufficient to induce the first-dose reaction.

  5. Single chain Fc-dimer-human growth hormone fusion protein for improved drug delivery.

    Science.gov (United States)

    Zhou, Li; Wang, Hsuan-Yao; Tong, Shanshan; Okamoto, Curtis T; Shen, Wei-Chiang; Zaro, Jennica L

    2017-02-01

    Fc fusion protein technology has been successfully used to generate long-acting forms of several protein therapeutics. In this study, a novel Fc-based drug carrier, single chain Fc-dimer (sc(Fc) 2 ), was designed to contain two Fc domains recombinantly linked via a flexible linker. Since the Fc dimeric structure is maintained through the flexible linker, the hinge region was omitted to further stabilize it against proteolysis and reduce FcγR-related effector functions. The resultant sc(Fc) 2 candidate preserved the neonatal Fc receptor (FcRn) binding. sc(Fc) 2 -mediated delivery was then evaluated using a therapeutic protein with a short plasma half-life, human growth hormone (hGH), as the protein drug cargo. This novel carrier protein showed a prolonged in vivo half-life and increased hGH-mediated bioactivity compared to the traditional Fc-based drug carrier. sc(Fc) 2 technology has the potential to greatly advance and expand the use of Fc-technology for improving the pharmacokinetics and bioactivity of protein therapeutics. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. 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.

  7. The Pathogenicity of Anti-β2GP1-IgG Autoantibodies Depends on Fc Glycosylation

    Directory of Open Access Journals (Sweden)

    Christoph Fickentscher

    2015-01-01

    Full Text Available To analyze the glycosylation of anti-β2GP1, we investigated purified IgG from healthy children, patients with APS, and asymptomatic adult carriers of antiphospholipid antibodies. We observed that in the sera of healthy children and of patients with APS, IgG3 and IgG2 were predominant, respectively. The potentially protective anti-β2GP1-IgM was lower in the sera of healthy children. Although anti-β2GP1-associated C1q did not differ between children and patients with antiphospholipid syndrome, the associated C3c was significantly higher in the sera of healthy children. This indicates a more efficient clearance of anti-β2GP1 immune complexes in the healthy children. This clearance is not accompanied by inflammation or coagulatory events. It is likely that the most important pathogenic factor of the anti-β2GP1-IgG is related to the different glycosylation observed in healthy and diseased individuals. We detected a significantly higher sialylation of anti-β2GP1-IgG isolated from the sera of healthy children and asymptomatic adults when compared with that of patients with clinically apparent antiphospholipid syndrome. Low sialylated IgG reportedly ameliorates inflammation and inflammation promotes hyposialylation. Thus, both reactions create a vicious circle that precipitates the pathology of the antiphospholipid syndrome including thrombus-formation. We conclude that the increased sialylation of anti-β2GP1-IgG of sera of healthy individuals limits their pathogenicity.

  8. Binding of C-reactive protein to human polymorphonuclear leukocytes: evidence for association of binding sites with Fc receptors

    International Nuclear Information System (INIS)

    Mueller, H.; Fehr, J.

    1986-01-01

    The functional similarities between C-reactive protein (CRP) and IgG raised the question as to whether human phagocytes are stimulated by CRP in the same way as by binding of antigen-complexes or aggregated IgG to their Fc receptors. Studies with the use of highly purified 125 I-labeled CRP showed specific and saturable binding to human polymorphonuclear leukocytes (PNM) with a K/sub D/ of 10.5 +/- 5.7 x 10 -8 M only when carried out in heat-inactivated plasma. The number of specific binding sites per cell was estimated at 1 to 3 x 10 6 . Competitive inhibition of CRP binding by antigen-complexed or aggregated IgG suggests CRP binding sites to be associated IgG suggests CRP binding sites to be associated with PMN Fc receptors. Only when assayed in heat-inactivated plasma did CRP binding induce adherence of cells to tissue culture dishes. However, no metabolic and potentially cytotoxic simulation of PMN was detected during CRP plasma-dependent attachment to surfaces: induction of aggregation, release of secondary granule constituents, and activation of the hexose monophosphate pathway were not observed. These results imply that CRP-PMN interactions is dependent on an additional factor present in heat-inactivated plasma and is followed only by a complement-independent increase in PMN attachment to surfaces. Because CRP was found to be deposits at sites of tissue injury, the CRP-mediated adherence of PMN may be an important step in localizing an inflammatory focus

  9. A Secondary Antibody-Detecting Molecular Weight Marker with Mouse and Rabbit IgG Fc Linear Epitopes for Western Blot Analysis.

    Science.gov (United States)

    Lin, Wen-Wei; Chen, I-Ju; Cheng, Ta-Chun; Tung, Yi-Ching; Chu, Pei-Yu; Chuang, Chih-Hung; Hsieh, Yuan-Chin; Huang, Chien-Chiao; Wang, Yeng-Tseng; Kao, Chien-Han; Roffler, Steve R; Cheng, Tian-Lu

    2016-01-01

    Molecular weight markers that can tolerate denaturing conditions and be auto-detected by secondary antibodies offer great efficacy and convenience for Western Blotting. Here, we describe M&R LE protein markers which contain linear epitopes derived from the heavy chain constant regions of mouse and rabbit immunoglobulin G (IgG Fc LE). These markers can be directly recognized and stained by a wide range of anti-mouse and anti-rabbit secondary antibodies. We selected three mouse (M1, M2 and M3) linear IgG1 and three rabbit (R1, R2 and R3) linear IgG heavy chain epitope candidates based on their respective crystal structures. Western blot analysis indicated that M2 and R2 linear epitopes are effectively recognized by anti-mouse and anti-rabbit secondary antibodies, respectively. We fused the M2 and R2 epitopes (M&R LE) and incorporated the polypeptide in a range of 15-120 kDa auto-detecting markers (M&R LE protein marker). The M&R LE protein marker can be auto-detected by anti-mouse and anti-rabbit IgG secondary antibodies in standard immunoblots. Linear regression analysis of the M&R LE protein marker plotted as gel mobility versus the log of the marker molecular weights revealed good linearity with a correlation coefficient R2 value of 0.9965, indicating that the M&R LE protein marker displays high accuracy for determining protein molecular weights. This accurate, regular and auto-detected M&R LE protein marker may provide a simple, efficient and economical tool for protein analysis.

  10. Field flow fractionation for assessing neonatal Fc receptor and Fcγ receptor binding to monoclonal antibodies in solution.

    Science.gov (United States)

    Pollastrini, Joey; Dillon, Thomas M; Bondarenko, Pavel; Chou, Robert Y-T

    2011-07-01

    Analysis of the strength and stoichiometry of immunoglobulin G (IgG) binding to neonatal Fc receptor (FcRn) and Fcγ receptor (FcγR) is important for evaluating the pharmacokinetics and effector functions of therapeutic monoclonal antibody (mAb) products, respectively. The current standard for assessing FcγR and FcRn binding is composed of cell-based and surface plasmon resonance (SPR) assays. In this work, asymmetrical flow field flow fractionation (AF4) was evaluated to establish the true stoichiometry of IgG binding in solution. AF4 and liquid chromatography-mass spectrometry (LC-MS) were applied to directly observe IgG/FcγR and IgG/FcRn complexes, which were not observed using nonequilibrium size exclusion chromatography (SEC) analysis. Human serum albumin (HSA), an abundant component of human blood and capable of binding FcRn, was studied in combination with FcRn and IgG. AF4 demonstrated that the majority of large complexes of IgG/FcRn/HSA were at an approximate 1:2:1 molar ratio. In addition, affinity measurements of the complex were performed in the sub-micromolar affinity range. A significant decrease in binding was detected for IgG molecules with increased oxidation in the Fc region. AF4 was useful in detecting weak binding between full-length IgG/Fc fragments and Fc receptors and the effect of chemical modifications on binding. AF4 is a useful technique in the assessment of mAb product quality attributes. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. The apparent monovalency of human IgG4 is due to bispecificity

    NARCIS (Netherlands)

    Aalberse, R. C.; Schuurman, J.; van Ree, R.

    1999-01-01

    A hypothesis is put forward to explain the apparent monovalency of human IgG4. It is based upon the known instability of the IgG4 hinge. IgG4 is secreted as a regular bivalent antibody, but after secretion interacts with another IgG4 molecule. This interaction results in the exchange of half

  12. Cross-Linking GPVI-Fc by Anti-Fc Antibodies Potentiates Its Inhibition of Atherosclerotic Plaque- and Collagen-Induced Platelet Activation

    Directory of Open Access Journals (Sweden)

    Janina Jamasbi, RPh

    2016-04-01

    Full Text Available To enhance the antithrombotic properties of recombinant glycoprotein VI fragment crystallizable (GPVI-Fc, the authors incubated GPVI-Fc with anti-human Fc antibodies to cross-link the Fc tails of GPVI-Fc. Cross-linking potentiated the inhibition of human plaque- and collagen-induced platelet aggregation by GPVI-Fc under static and flow conditions without increasing bleeding time in vitro. Cross-linking with anti-human-Fc Fab2 was even superior to anti-human-Fc immunoglobulin G (IgG. Advanced optical imaging revealed a continuous sheath-like coverage of collagen fibers by cross-linked GPVI-Fc complexes. Cross-linking of GPVI into oligomeric complexes provides a new, highly effective, and probably safe antithrombotic treatment as it suppresses platelet GPVI-plaque interaction selectively at the site of acute atherothrombosis.

  13. Estimation of polyclonal IgG4 hybrids in normal human serum.

    Science.gov (United States)

    Young, Elizabeth; Lock, Emma; Ward, Douglas G; Cook, Alexander; Harding, Stephen; Wallis, Gregg L F

    2014-07-01

    The in vivo or in vitro formation of IgG4 hybrid molecules, wherein the immunoglobulins have exchanged half molecules, has previously been reported under experimental conditions. Here we estimate the incidence of polyclonal IgG4 hybrids in normal human serum and comment on the existence of IgG4 molecules with different immunoglobulin light chains. Polyclonal IgG4 was purified from pooled or individual donor human sera and sequentially fractionated using light-chain affinity and size exclusion chromatography. Fractions were analysed by SDS-PAGE, immunoblotting, ELISA, immunodiffusion and matrix-assisted laser-desorption mass spectrometry. Polyclonal IgG4 purified from normal serum contained IgG4κ, IgG4λ and IgG4κ/λ molecules. Size exclusion chromatography showed that IgG4 was principally present in monomeric form (150 000 MW). SDS-PAGE, immunoblotting and ELISA showed the purity of the three IgG4 samples. Immunodiffusion, light-chain sandwich ELISA and mass spectrometry demonstrated that both κ and λ light chains were present on only the IgG4κ/λ molecules. The amounts of IgG4κ/λ hybrid molecules ranged from 21 to 33% from the five sera analysed. Based on the molecular weight these molecules were formed of two IgG4 heavy chains plus one κ and one λ light chain. Polyclonal IgG (IgG4-depleted) was similarly fractionated according to light-chain specificity. No evidence of hybrid IgG κ/λ antibodies was observed. These results indicate that hybrid IgG4κ/λ antibodies compose a substantial portion of IgG4 from normal human serum. © 2014 John Wiley & Sons Ltd.

  14. Adsorption of IgG onto hydrophobic teflon. Differences between the F(ab) and F(c) domains

    NARCIS (Netherlands)

    Vermeer, AWP; Giacomelli, CE; Norde, W

    2001-01-01

    The effect of differences in the degree of hydrophobicity of protein patches/fragments on the adsorption behaviour of the protein is investigated. The adsorption isotherm of a monoclonal mouse anti-human immunoglobulin G (isotype 2b) onto hydrophobic Teflon particles is measured using a depletion

  15. Serological blind spots for variants of human IgG3 and IgG4 by a commonly used anti-immunoglobulin reagent.

    Science.gov (United States)

    Howie, Heather L; Delaney, Meghan; Wang, Xiaohong; Er, Lay See; Vidarsson, Gestur; Stegmann, Tamara C; Kapp, Linda; Lebedev, Jenna N; Wu, Yanyun; AuBuchon, James P; Zimring, James C

    2016-12-01

    Human immunoglobulin G (IgG) includes four different subtypes (IgG1, IgG2, IgG3, and IgG4), and it is also now appreciated that there are genetic variations within IgG subtypes (called isoallotypes). Twenty-nine different isoallotypes have been described, with 7, 4, 15, and 3 isoallotypes described for IgG1, IgG2, IgG3, and IgG4, respectively. The reactivity of anti-IgG with different isoallotypes has not been characterized. A novel monoclonal anti-K antibody (PugetSound Monoclonal Antibody 1 [PUMA1]) was isolated and sequenced, and a panel of PUMA1 variants was expressed, consisting of the 29 known IgG isoallotypes. The resulting panel of antibodies was preincubated with K-positive red blood cells (RBCs) and then subjected to testing with currently approved anti-IgG by flow cytometry, solid phase systems, gel cards, and tube testing. A US Food and Drug Administration (FDA)-approved monoclonal anti-IgG (gamma-clone) failed to recognize 2 of 15 IgG3 isoallotypes (IgG3-03 and IgG3-13) and 3 of 3 IgG4 isoallotypes (IgG4-01, IgG4-02, and IgG4-03). In contrast, an FDA-approved rabbit polyclonal anti-IgG recognized each of the known human IgG isoallotypes. These findings demonstrate "blind spots" in isoalloantibody detection by a monoclonal anti-IgG. If a patient has anti-RBC antibodies predominantly of an IgG3 subtype (the IgG3-03 and/or IgG3-13 variety), then it is possible that a clinically significant alloantibody would be missed. IgG-03 and IgG-13 have an estimated frequency of 1% to 3% in Caucasian populations and 20% to 30% in certain African populations. Nonreactivity with IgG4 is a known characteristic of this monoclonal anti-IgG, but IgG4 isoallotypes have not been previously reported. © 2016 AABB.

  16. The Emerging Importance of IgG Fab Glycosylation in Immunity

    NARCIS (Netherlands)

    van de Bovenkamp, Fleur S.; Hafkenscheid, Lise; Rispens, Theo; Rombouts, Yoann

    2016-01-01

    Human IgG is the most abundant glycoprotein in serum and is crucial for protective immunity. In addition to conserved IgG Fc glycans, ∼15-25% of serum IgG contains glycans within the variable domains. These so-called "Fab glycans" are primarily highly processed complex-type biantennary N-glycans

  17. Maternofetal transplacental transport of recombinant IgG antibodies lacking effector functions

    DEFF Research Database (Denmark)

    Mathiesen, Line; Nielsen, Leif K; Andersen, Jan Terje

    2013-01-01

    alloimmunity, which may be lethal. A novel strategy to control pathogenic antibodies would be administration of a non-destructive IgG antibody blocking antigen binding while retaining binding to FcRn. We report on two human IgG3 antibodies with a hinge deletion and a C131S point mutation (IgG3ΔHinge...

  18. Differential Use of Human Neutrophil Fcγ Receptors for Inducing Neutrophil Extracellular Trap Formation.

    Science.gov (United States)

    Alemán, Omar Rafael; Mora, Nancy; Cortes-Vieyra, Ricarda; Uribe-Querol, Eileen; Rosales, Carlos

    2016-01-01

    Neutrophils (PMN) are the most abundant leukocytes in the blood. PMN migrate from the circulation to sites of infection, where they are responsible for antimicrobial functions. PMN use phagocytosis, degranulation, and formation of neutrophil extracellular traps (NETs) to kill microbes. NETs are fibers composed of chromatin and neutrophil-granule proteins. Several pathogens, including bacteria, fungi, and parasites, and also some pharmacological stimuli such as phorbol 12-myristate 13-acetate (PMA) are efficient inducers of NETs. Antigen-antibody complexes are also capable of inducing NET formation. However the particular Fcγ receptor involved in triggering this function is a matter of controversy. In order to provide some insight into what Fcγ receptor is responsible for NET formation, each of the two human Fcγ receptors was stimulated individually by specific monoclonal antibodies and NET formation was evaluated. FcγRIIa cross-linking did not promote NET formation. Cross-linking other receptors such as integrins also did not promote NET formation. In contrast FcγRIIIb cross-linking induced NET formation similarly to PMA stimulation. NET formation was dependent on NADPH-oxidase, PKC, and ERK activation. These data show that cross-linking FcγRIIIb is responsible for NET formation by the human neutrophil.

  19. Differential Use of Human Neutrophil Fcγ Receptors for Inducing Neutrophil Extracellular Trap Formation

    Directory of Open Access Journals (Sweden)

    Omar Rafael Alemán

    2016-01-01

    Full Text Available Neutrophils (PMN are the most abundant leukocytes in the blood. PMN migrate from the circulation to sites of infection, where they are responsible for antimicrobial functions. PMN use phagocytosis, degranulation, and formation of neutrophil extracellular traps (NETs to kill microbes. NETs are fibers composed of chromatin and neutrophil-granule proteins. Several pathogens, including bacteria, fungi, and parasites, and also some pharmacological stimuli such as phorbol 12-myristate 13-acetate (PMA are efficient inducers of NETs. Antigen-antibody complexes are also capable of inducing NET formation. However the particular Fcγ receptor involved in triggering this function is a matter of controversy. In order to provide some insight into what Fcγ receptor is responsible for NET formation, each of the two human Fcγ receptors was stimulated individually by specific monoclonal antibodies and NET formation was evaluated. FcγRIIa cross-linking did not promote NET formation. Cross-linking other receptors such as integrins also did not promote NET formation. In contrast FcγRIIIb cross-linking induced NET formation similarly to PMA stimulation. NET formation was dependent on NADPH-oxidase, PKC, and ERK activation. These data show that cross-linking FcγRIIIb is responsible for NET formation by the human neutrophil.

  20. Relative stabilities of IgG1 and IgG4 Fab domains: Influence of the light–heavy interchain disulfide bond architecture

    Science.gov (United States)

    Heads, James T; Adams, Ralph; D'Hooghe, Lena E; Page, Matt J T; Humphreys, David P; Popplewell, Andrew G; Lawson, Alastair D; Henry, Alistair J

    2012-01-01

    The stability of therapeutic antibodies is a prime pharmaceutical concern. In this work we examined thermal stability differences between human IgG1 and IgG4 Fab domains containing the same variable regions using the thermofluor assay. It was found that the IgG1 Fab domain is up to 11°C more stable than the IgG4 Fab domain containing the same variable region. We investigated the cause of this difference with the aim of developing a molecule with the enhanced stability of the IgG1 Fab and the biological properties of an IgG4 Fc. We found that replacing the seven residues, which differ between IgG1 CH1 and IgG4 CH1 domains, while retaining the native IgG1 light-heavy interchain disulfide (L–H) bond, did not affect thermal stability. Introducing the IgG1 type L–H interchain disulfide bond (DSB) into the IgG4 Fab resulted in an increase in thermal stability to levels observed in the IgG1 Fab with the same variable region. Conversely, replacement of the IgG1 L–H interchain DSB with the IgG4 type L–H interchain DSB reduced the thermal stability. We utilized the increased stability of the IgG1 Fab and designed a hybrid antibody with an IgG1 CH1 linked to an IgG4 Fc via an IgG1 hinge. This construct has the expected biophysical properties of both the IgG4 Fc and IgG1 Fab domains and may therefore be a pharmaceutically relevant format. PMID:22761163

  1. A soluble form of the high affinity IgE receptor, Fc-epsilon-RI, circulates in human serum.

    Directory of Open Access Journals (Sweden)

    Eleonora Dehlink

    Full Text Available Soluble IgE receptors are potential in vivo modulators of IgE-mediated immune responses and are thus important for our basic understanding of allergic responses. We here characterize a novel soluble version of the IgE-binding alpha-chain of Fc-epsilon-RI (sFcεRI, the high affinity receptor for IgE. sFcεRI immunoprecipitates as a protein of ∼40 kDa and contains an intact IgE-binding site. In human serum, sFcεRI is found as a soluble free IgE receptor as well as a complex with IgE. Using a newly established ELISA, we show that serum sFcεRI levels correlate with serum IgE in patients with elevated IgE. We also show that serum of individuals with normal IgE levels can be found to contain high levels of sFcεRI. After IgE-antigen-mediated crosslinking of surface FcεRI, we detect sFcεRI in the exosome-depleted, soluble fraction of cell culture supernatants. We further show that sFcεRI can block binding of IgE to FcεRI expressed at the cell surface. In summary, we here describe the alpha-chain of FcεRI as a circulating soluble IgE receptor isoform in human serum.

  2. Generating and Purifying Fab Fragments from Human and Mouse IgG Using the Bacterial Enzymes IdeS, SpeB and Kgp.

    Science.gov (United States)

    Sjögren, Jonathan; Andersson, Linda; Mejàre, Malin; Olsson, Fredrik

    2017-01-01

    Fab fragments are valuable research tools in various areas of science including applications in imaging, binding studies, removal of Fc-mediated effector functions, mass spectrometry, infection biology, and many others. The enzymatic tools for the generation of Fab fragments have been discovered through basic research within the field of molecular bacterial pathogenesis. Today, these enzymes are widely applied as research tools and in this chapter, we describe methodologies based on bacterial enzymes to generate Fab fragments from both human and mouse IgG. For all human IgG subclasses, the IdeS enzyme from Streptococcus pyogenes has been applied to generate F(ab')2 fragments that subsequently can be reduced under mild conditions to generate a homogenous pool of Fab' fragments. The enzyme Kgp from Porphyromonas gingivalis has been applied to generate intact Fab fragments from human IgG1 and the Fab fragments can be purified using a CH1-specific affinity resin. The SpeB protease, also from S. pyogenes, is able to digest mouse IgGs and has been applied to digest antibodies and Fab fragments can be purified on light chain affinity resins. In this chapter, we describe methodologies that can be used to obtain Fab fragments from human and mouse IgG using bacterial proteases.

  3. FcGammaRIIa polymorphism and anti-malaria specific IgG and IgG subclass responses in populations differing in susceptibility to malaria in Burkina Faso

    DEFF Research Database (Denmark)

    Cherif, Mariama K; Sanou, Guillaume S; Maiga, Boubakar

    2012-01-01

    Fc¿RIIa is known to be polymorphic; and certain variants err associated with differt susceptibilities to malaria. Studies involving the Fulani ethnic group reported an ethnic difference in Fc¿RIIa-R131H genotype frequencies between the Fulani and other sympatric groups. No previous studies have a...

  4. (Some) Cellular Mechanisms Influencing the Transcription of Human Endogenous Retrovirus, HERV-Fc1

    DEFF Research Database (Denmark)

    Laska, Magdalena Janina; Nissen, Kari Konstantin; Nexø, Bjørn Andersen

    2013-01-01

    DNA methylation and histone acetylation are epigenetic modifications that act as regulators of gene expression. DNA methylation is considered an important mechanism for silencing of retroelements in the mammalian genome. However, the methylation of human endogenous retroviruses (HERVs) is not well...... investigated. The aim of this study was to investigate the transcriptional potential of HERV-Fc1 proviral 5'LTR in more detail, and examined the specific influence of CpG methylation on this LTR in number of cell lines. Specifically, the role of demethylating chemicals e.g. 5-aza-2' deoxycytidine...... and Trichostatin-A, in inducing or reactivating expression of HERV-Fc1 specific sequences and the mechanisms were investigated. In our present study, 5-aza-dC is shown to be a powerful inducer of HERV-Fc1, and at the same time it strongly inhibits methylation of DNA. Treatment with this demethylating agent 5-aza...

  5. Therapeutic IgG4 antibodies engage in Fab-arm exchange with endogenous human IgG4 in vivo

    NARCIS (Netherlands)

    Labrijn, Aran F.; Buijsse, Antonio Ortiz; van den Bremer, Ewald T. J.; Verwilligen, Annemiek Y. W.; Bleeker, Wim K.; Thorpe, Susan J.; Killestein, Joep; Polman, Chris H.; Aalberse, Rob C.; Schuurman, Janine; van de Winkel, Jan G. J.; Parren, Paul W. H. I.

    Two humanized IgG4 antibodies, natalizumab and gemtuzumab, are approved for human use, and several others, like TGN1412, are or have been in clinical development. Although IgG4 antibodies can dynamically exchange half-molecules(1), Fab-arm exchange with therapeutic antibodies has not been

  6. Therapeutic IgG4 antibodies engage in Fab-arm exchange with endogenous human IgG4 in vivo

    NARCIS (Netherlands)

    Labrijn, Aran F.; Buijsse, Antonio Ortiz; van den Bremer, Ewald T. J.; Verwilligen, Annemiek Y. W.; Bleeker, Wim K.; Thorpe, Susan J.; Killestein, Joep; Polman, Chris H.; Aalberse, Rob C.; Schuurman, Janine; van de Winkel, Jan G. J.; Parren, Paul W. H. I.

    2009-01-01

    Two humanized IgG4 antibodies, natalizumab and gemtuzumab, are approved for human use, and several others, like TGN1412, are or have been in clinical development. Although IgG4 antibodies can dynamically exchange half-molecules, Fab-arm exchange with therapeutic antibodies has not been demonstrated

  7. Non-immune binding of human IgG to M-related proteins confers resistance to phagocytosis of group A streptococci in blood.

    Directory of Open Access Journals (Sweden)

    Harry S Courtney

    Full Text Available The non-immune binding of immunoglobulins by bacteria is thought to contribute to the pathogenesis of infections. M-related proteins (Mrp are group A streptococcal (GAS receptors for immunoglobulins, but it is not known if this binding has any impact on virulence. To further investigate the binding of immunoglobulins to Mrp, we engineered mutants of an M type 4 strain of GAS by inactivating the genes for mrp, emm, enn, sof, and sfbX and tested these mutants in IgG-binding assays. Inactivation of mrp dramatically decreased the binding of human IgG, whereas inactivation of emm, enn, sof, and sfbx had only minor effects, indicating that Mrp is a major IgG-binding protein. Binding of human immunoglobulins to a purified, recombinant form of Mrp indicated that it selectively binds to the Fc domain of human IgG, but not IgA or IgM and that it preferentially bound subclasses IgG₁>IgG₄>IgG₂>IgG₃. Recombinant proteins encompassing different regions of Mrp were engineered and used to map its IgG-binding domain to its A-repeat region and a recombinant protein with 3 A-repeats was a better inhibitor of IgG binding than one with a single A-repeat. A GAS mutant expressing Mrp with an in-frame deletion of DNA encoding the A-repeats had a dramatically reduced ability to bind human IgG and to grow in human blood. Mrp exhibited host specificity in binding IgG; human IgG was the best inhibitor of the binding of IgG followed by pig, horse, monkey, and rabbit IgG. IgG from goat, mouse, rat, cow, donkey, chicken, and guinea pig were poor inhibitors of binding. These findings indicate that Mrp preferentially binds human IgG and that this binding contributes to the ability of GAS to resist phagocytosis and may be a factor in the restriction of GAS infections to the human host.

  8. Investigating the Interaction between the Neonatal Fc Receptor and Monoclonal Antibody Variants by Hydrogen/Deuterium Exchange Mass Spectrometry

    DEFF Research Database (Denmark)

    Jensen, Pernille Foged; Larraillet, Vincent; Schlothauer, Tilman

    2015-01-01

    The recycling of immunoglobulins by the neonatal Fc receptor (FcRn) is of crucial importance in the maintenance of antibody levels in plasma and is responsible for the long half-lives of endogenous and recombinant monoclonal antibodies. From a therapeutic point of view there is great interest...... in understanding and modulating the IgG-FcRn interaction to optimize antibody pharmacokinetics and ultimately improve efficacy and safety. Here we studied the interaction between a full-length human IgG1 and human FcRn via hydrogen/deuterium exchange mass spectrometry and targeted electron transfer dissociation...... to map sites perturbed by binding on both partners of the IgG-FcRn complex. Several regions in the antibody Fc region and the FcRn were protected from exchange upon complex formation, in good agreement with previous crystallographic studies of FcRn in complex with the Fc fragment. Interestingly, we found...

  9. Human Endogenous Retrovirus HERV-Fc1 Association with Multiple Sclerosis Susceptibility: A Meta-Analysis

    Science.gov (United States)

    García-Montojo, Marta; Alcina, Antonio; Fedetz, María; Alloza, Iraide; Astobiza, Ianire; Leyva, Laura; Fernández, Oscar; Izquierdo, Guillermo; Antigüedad, Alfredo; Arroyo, Rafael; Álvarez-Lafuente, Roberto; Vandenbroeck, Koen; Matesanz, Fuencisla; Urcelay, Elena

    2014-01-01

    Background Human endogenous retroviruses (HERVs) are repetitive sequences derived from ancestral germ-line infections by exogenous retroviruses and different HERV families have been integrated in the genome. HERV-Fc1 in chromosome X has been previously associated with multiple sclerosis (MS) in Northern European populations. Additionally, HERV-Fc1 RNA levels of expression have been found increased in plasma of MS patients with active disease. Considering the North-South latitude gradient in MS prevalence, we aimed to evaluate the role of HERV-Fc1on MS risk in three independent Spanish cohorts. Methods A single nucleotide polymorphism near HERV-Fc1, rs391745, was genotyped by Taqman chemistry in a total of 2473 MS patients and 3031 ethnically matched controls, consecutively recruited from: Northern (569 patients and 980 controls), Central (883 patients and 692 controls) and Southern (1021 patients and 1359 controls) Spain. Our results were pooled in a meta-analysis with previously published data. Results Significant associations of the HERV-Fc1 polymorphism with MS were observed in two Spanish cohorts and the combined meta-analysis with previous data yielded a significant association [rs391745 C-allele carriers: pM-H = 0.0005; ORM-H (95% CI) = 1.27 (1.11–1.45)]. Concordantly to previous findings, when the analysis was restricted to relapsing remitting and secondary progressive MS samples, a slight enhancement in the strength of the association was observed [pM-H = 0.0003, ORM-H (95% CI) = 1.32 (1.14–1.53)]. Conclusion Association of the HERV-Fc1 polymorphism rs391745 with bout-onset MS susceptibility was confirmed in Southern European cohorts. PMID:24594754

  10. A rapid radioassay for human IgG produced in lymphocyte in vitro culture systems

    International Nuclear Information System (INIS)

    Weightman, D.R.; Shale, D.J.; Tomlinson, W.R.

    1981-01-01

    Protein A bearing Staphylococcus aureus was used to develop a solid-phase radioassay for IgG immunoglobulins. The assay was specifically optimised for use in vitro human lymphocyte culture work. Compared with a solid-phase radioimmunoassay for IgG produced in lymphocyte culture, this assay had a similar performance profile and the advantages of rapidity and technical ease. (Auth.)

  11. Human IgG repertoire of malaria antigen-immunized human immune system (HIS) mice.

    Science.gov (United States)

    Nogueira, Raquel Tayar; Sahi, Vincent; Huang, Jing; Tsuji, Moriya

    2017-08-01

    Humanized mouse models present an important tool for preclinical evaluation of new vaccines and therapeutics. Here we show the human variable repertoire of antibody sequences cloned from a previously described human immune system (HIS) mouse model that possesses functional human CD4+ T cells and B cells, namely HIS-CD4/B mice. We sequenced variable IgG genes from single memory B-cell and plasma-cell sorted from splenocytes or whole blood lymphocytes of HIS-CD4/B mice that were vaccinated with a human plasmodial antigen, a recombinant Plasmodium falciparum circumsporozoite protein (rPfCSP). We demonstrate that rPfCSP immunization triggers a diverse B-cell IgG repertoire composed of various human VH family genes and distinct V(D)J recombinations that constitute diverse CDR3 sequences similar to humans, although low hypermutated sequences were generated. These results demonstrate the substantial genetic diversity of responding human B cells of HIS-CD4/B mice and their capacity to mount human IgG class-switched antibody response upon vaccination. Copyright © 2017 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.

  12. A three-layer immunoradiometric assay for determination of IgG subclass antibodies in Human Sera (''IgG subclass RAST'')

    International Nuclear Information System (INIS)

    Djurup, R.; Soendergaard, I.; Weeke, B.; University of Copenhagen, Denmark); Magnusson, C.G.M.

    1984-01-01

    We report the development of a three-layer immunoradiometric assay (TIRA) for measurement of IgG antibodies of all four subclasses in human sera. The first layer consists of diluted human serum, the second layer is monoclonal mouse antibodies to human IgG subclasses, and the third layer is 125 I-labelled rabbit anti-mouse IgG. Monoclonal anti-IgGI, anti-IgG3 and anti-IgG4 reacted only with their complementary IgG subclass, whereas the anti-IgG2 showed slight cross-reactivity to immunoglobins of other subclasses and classes and to light chain proteins. The observed cross-reactivity was found to be without importance, when the TIRA was applied to measurement of IgG subclass antibodies. Equipotency was established by use of appropriate dilutions of the monoclonal antibodies, and the assay was calibrated by use of human reference serum. The TIRA therefore permits reliable inter-individual and intra-individual comparisons of the IgG antibody response in all four subclasses. Non-specific binding obtained with pooled normal human serum was below 0.33%. Inter-assay coefficient of variation was between 18 and 27%. The TIRA was applied to measurement of IgG subclass antibodies to timothy grass pollen in sera from grass pollen allergies undergoing immunotherapy. (author)

  13. Gamma interferon augments Fc gamma receptor-mediated dengue virus infection of human monocytic cells.

    OpenAIRE

    Kontny, U; Kurane, I; Ennis, F A

    1988-01-01

    It has been reported that anti-dengue antibodies at subneutralizing concentrations augment dengue virus infection of monocytic cells. This is due to the increased uptake of dengue virus in the form of virus-antibody complexes by cells via Fc gamma receptors. We analyzed the effects of recombinant human gamma interferon (rIFN-gamma) on dengue virus infection of human monocytic cells. U937 cells, a human monocytic cell line, were infected with dengue virus in the form of virus-antibody complexe...

  14. Loci associated with N-glycosylation of human immunoglobulin G show pleiotropy with autoimmune diseases and haematological cancers

    NARCIS (Netherlands)

    Lauc, G.; Huffman, J.E.; Pucic, M.; Zgaga, L.; Adamczyk, B.; Muzinic, A.; Novokmet, M.; Polasek, O.; Gornik, O.; Kristic, J.; Keser, T.; Vitart, V.; Scheijen, B.; Uh, H.W.; Molokhia, M.; Patrick, A.L.; McKeigue, P.; Kolcic, I.; Lukic, I.K.; Swann, O.; Leeuwen, F.N. van; Ruhaak, L.R.; Houwing-Duistermaat, J.J.; Slagboom, P.E.; Beekman, M.; Craen, A.J. de; Deelder, A.M.; Zeng, Q.; Wang, W.; Hastie, N.D.; Gyllensten, U.; Wilson, J.F.; Wuhrer, M.; Wright, A.F.; Rudd, P.M.; Hayward, C.; Aulchenko, Y.; Campbell, H.; Rudan, I.

    2013-01-01

    Glycosylation of immunoglobulin G (IgG) influences IgG effector function by modulating binding to Fc receptors. To identify genetic loci associated with IgG glycosylation, we quantitated N-linked IgG glycans using two approaches. After isolating IgG from human plasma, we performed 77 quantitative

  15. 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

  16. The Fc-receptor III of cultured human monocytes. Structural similarity with FcRIII of natural killer cells and role in the extracellular lysis of sensitized erythrocytes

    NARCIS (Netherlands)

    Klaassen, R. J.; Ouwehand, W. H.; Huizinga, T. W.; Engelfriet, C. P.; von dem Borne, A. E.

    1990-01-01

    FcRIII is not present on peripheral blood monocytes, but becomes expressed upon culturing and can be demonstrated on tissue macrophages. We studied the expression of FcRIII of cultured monocytes in detail and compared its structure with FcRIII of neutrophils and NK cells. The cell density of FcRIII

  17. Hydrodynamic delivery of plasmid DNA encoding human Fc?R-Ig dimers blocks immune-complex mediated inflammation in mice

    OpenAIRE

    Shashidharamurthy, Rangaiah; Machiah, Deepa; Bozeman, Erica N.; Srivatsan, Sanjay; Patel, Jaina; Cho, Alice; Jacob, Joshy; Selvaraj, Periasamy

    2011-01-01

    Therapeutic use and function of recombinant molecules can be studied by the expression of foreign genes in mice. In this study, we have expressed human Fcgamma receptor ?Ig fusion molecules (Fc?R-Igs) in mice by administering Fc?R-Ig plasmid DNAs hydrodynamically and compared their effectiveness to purified molecules in blocking immune-complex (IC) mediated inflammation in mice. The concentration of hydrodynamically expressed Fc?R-Igs (CD16AF-Ig, CD32AR-Ig and CD32AH-Ig) reached a maximum of ...

  18. Increased half-life and enhanced potency of Fc-modified human PCSK9 monoclonal antibodies in primates.

    Directory of Open Access Journals (Sweden)

    Yijun Shen

    Full Text Available Blocking proprotein convertase subtilisin kexin type 9 (PCSK9 binding to low-density lipoprotein receptor (LDLR can profoundly lower plasma LDL levels. Two anti-PCKS9 monoclonal antibodies (mAbs, alirocumab and evolocumab, were approved by the FDA in 2015. The recommended dose is 75 mg to 150 mg every two weeks for alirocumab and 140mg every two weeks or 420 mg once a month for evolocumab. This study attempted to improve the pharmacokinetic properties of F0016A, an IgG1 anti-PCKS9 mAb, to generate biologically superior molecules. We engineered several variants with two or three amino acid substitutions in the Fc fragment based on prior knowledge. The Fc-modified mAbs exhibited increased binding to FcRn, resulting in prolonged serum half-life and enhanced efficacy in vivo. These results demonstrate that Fc-modified anti-PCKS9 antibodies may enable less frequent or lower dosing of antibodies by improved recycling into the blood.

  19. Restricted processing of CD16a/Fc γ receptor IIIa N-glycans from primary human NK cells impacts structure and function.

    Science.gov (United States)

    Patel, Kashyap R; Roberts, Jacob T; Subedi, Ganesh P; Barb, Adam W

    2018-03-09

    CD16a/Fc γ receptor IIIa is the most abundant antibody Fc receptor expressed on human natural killer (NK) cells and activates a protective cytotoxic response following engagement with antibody clustered on the surface of a pathogen or diseased tissue. Therapeutic monoclonal antibodies (mAbs) with greater Fc-mediated affinity for CD16a show superior therapeutic outcome; however, one significant factor that promotes antibody-CD16a interactions, the asparagine-linked carbohydrates ( N -glycans), remains undefined. Here, we purified CD16a from the primary NK cells of three donors and identified a large proportion of hybrid (22%) and oligomannose N -glycans (23%). These proportions indicated restricted N -glycan processing and were unlike those of the recombinant CD16a forms, which have predominantly complex-type N -glycans (82%). Tethering recombinant CD16a to the membrane by including the transmembrane and intracellular domains and via coexpression with the Fc ϵ receptor γ-chain in HEK293F cells was expected to produce N -glycoforms similar to NK cell-derived CD16a but yielded N -glycoforms different from NK cell-derived CD16a and recombinant soluble CD16a. Of note, these differences in CD16a N -glycan composition affected antibody binding: CD16a with oligomannose N -glycans bound IgG1 Fc with 12-fold greater affinity than did CD16a having primarily complex-type and highly branched N -glycans. The changes in binding activity mirrored changes in NMR spectra of the two CD16a glycoforms, indicating that CD16a glycan composition also affects the glycoprotein's structure. These results indicated that CD16a from primary human NK cells is compositionally, and likely also functionally, distinct from commonly used recombinant forms. Furthermore, our study provides critical evidence that cell lineage determines CD16a N -glycan composition and antibody-binding affinity. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Human IgG1 antibodies suppress angiogenesis in a target-independent manner

    NARCIS (Netherlands)

    Bogdanovich, Sasha; Kim, Younghee; Mizutani, Takeshi; Yasuma, Reo; Tudisco, Laura; Cicatiello, Valeria; Bastos-Carvalho, Ana; Kerur, Nagaraj; Hirano, Yoshio; Baffi, Judit Z; Tarallo, Valeria; Li, Shengjian; Yasuma, Tetsuhiro; Arpitha, Parthasarathy; Fowler, Benjamin J; Wright, Charles B; Apicella, Ivana; Greco, Adelaide; Brunetti, Arturo; Ruvo, Menotti; Sandomenico, Annamaria; Nozaki, Miho; Ijima, Ryo; Kaneko, Hiroki; Ogura, Yuichiro; Terasaki, Hiroko; Ambati, Balamurali K; Leusen, Jeanette HW; Langdon, Wallace Y; Clark, Michael R; Armour, Kathryn L; Bruhns, Pierre; Verbeek, J Sjef; Gelfand, Bradley D; De Falco, Sandro; Ambati, Jayakrishna

    2016-01-01

    Aberrant angiogenesis is implicated in diseases affecting nearly 10% of the world's population. The most widely used anti-angiogenic drug is bevacizumab, a humanized IgG1 monoclonal antibody that targets human VEGFA. Although bevacizumab does not recognize mouse Vegfa, it inhibits angiogenesis in

  1. 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.

  2. Identification of Fc Gamma Receptor Glycoforms That Produce Differential Binding Kinetics for Rituximab.

    Science.gov (United States)

    Hayes, Jerrard M; Frostell, Asa; Karlsson, Robert; Müller, Steffen; Martín, Silvia Míllan; Pauers, Martin; Reuss, Franziska; Cosgrave, Eoin F; Anneren, Cecilia; Davey, Gavin P; Rudd, Pauline M

    2017-10-01

    Fc gamma receptors (FcγR) bind the Fc region of antibodies and therefore play a prominent role in antibody-dependent cell-based immune responses such as ADCC, CDC and ADCP. The immune effector cell activity is directly linked to a productive molecular engagement of FcγRs where both the protein and glycan moiety of antibody and receptor can affect the interaction and in the present study we focus on the role of the FcγR glycans in this interaction. We provide a complete description of the glycan composition of Chinese hamster ovary (CHO) expressed human Fcγ receptors RI (CD64), RIIa Arg131/His131 (CD32a), RIIb (CD32b) and RIIIa Phe158/Val158 (CD16a) and analyze the role of the glycans in the binding mechanism with IgG. The interactions of the monoclonal antibody rituximab with each FcγR were characterized and we discuss the CHO-FcγRIIIa Phe158/Val158 and CHO-FcγRI interactions and compare them to the equivalent interactions with human (HEK293) and murine (NS0) produced receptors. Our results reveal clear differences in the binding profiles of rituximab, which we attribute in each case to the differences in host cell-dependent FcγR glycosylation. The glycan profiles of CHO expressed FcγRI and FcγRIIIa Phe158/Val158 were compared with the glycan profiles of the receptors expressed in NS0 and HEK293 cells and we show that the glycan type and abundance differs significantly between the receptors and that these glycan differences lead to the observed differences in the respective FcγR binding patterns with rituximab. Oligomannose structures are prevalent on FcγRI from each source and likely contribute to the high affinity rituximab interaction through a stabilization effect. On FcγRI and FcγRIIIa large and sialylated glycans have a negative impact on rituximab binding, likely through destabilization of the interaction. In conclusion, the data show that the IgG1-FcγR binding kinetics differ depending on the glycosylation of the FcγR and further support a

  3. Effect of trastuzumab interchain disulfide bond cleavage on Fcγ receptor binding and antibody-dependent tumour cell phagocytosis.

    Science.gov (United States)

    Suzuki, Mami; Yamanoi, Ayaka; Machino, Yusuke; Ootsubo, Michiko; Izawa, Ken-ichi; Kohroki, Junya; Masuho, Yasuhiko

    2016-01-01

    The Fc domain of human IgG1 binds to Fcγ receptors (FcγRs) to induce effector functions such as phagocytosis. There are four interchain disulfide bonds between the H and L chains. In this study, the disulfide bonds within the IgG1 trastuzumab (TRA), which is specific for HER2, were cleaved by mild S-sulfonation or by mild reduction followed by S-alkylation with three different reagents. The cleavage did not change the binding activities of TRA to HER2-bearing SK-BR-3 cells. The binding activities of TRA to FcγRIIA and FcγRIIB were greatly enhanced by modification with mild reduction and S-alkylation with ICH2CONH2 or N-(4-aminophenyl) maleimide, while the binding activities of TRA to FcγRI and FcγRIIIA were decreased by any of the four modifications. However, the interchain disulfide bond cleavage by the different modifications did not change the antibody-dependent cell-mediated phagocytosis (ADCP) of SK-BR-3 cells by activated THP-1 cells. The order of FcγR expression levels on the THP-1 cells was FcγRII > FcγRI > FcγRIII and ADCP was inhibited by blocking antibodies against FcγRI and FcγRII. These results imply that the effect of the interchain disulfide bond cleavage on FcγRs binding and ADCP is dependent on modifications of the cysteine residues and the FcγR isotypes. © The Authors 2015. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

  4. Conversion of a Mouse Fab into a Whole Humanized IgG Antibody for Detecting Botulinum Toxin

    National Research Council Canada - National Science Library

    Palys, Thomas J; Schmid, Kara E; Scherer, John M; Schoepp, Randal J

    2006-01-01

    .... Therefore we sought to convert a murine Fab into a whole humanized IgG. The variable regions from an anti-botulinum Fab were cloned into human IgG heavy and light chain vectors and produced in myeloma cells...

  5. Neuron-derived IgG protects neurons from complement-dependent cytotoxicity.

    Science.gov (United States)

    Zhang, Jie; Niu, Na; Li, Bingjie; McNutt, Michael A

    2013-12-01

    Passive immunity of the nervous system has traditionally been thought to be predominantly due to the blood-brain barrier. This concept must now be revisited based on the existence of neuron-derived IgG. The conventional concept is that IgG is produced solely by mature B lymphocytes, but it has now been found to be synthesized by murine and human neurons. However, the function of this endogenous IgG is poorly understood. In this study, we confirm IgG production by rat cortical neurons at the protein and mRNA levels, with 69.0 ± 5.8% of cortical neurons IgG-positive. Injury to primary-culture neurons was induced by complement leading to increases in IgG production. Blockage of neuron-derived IgG resulted in more neuronal death and early apoptosis in the presence of complement. In addition, FcγRI was found in microglia and astrocytes. Expression of FcγR I in microglia was increased by exposure to neuron-derived IgG. Release of NO from microglia triggered by complement was attenuated by neuron-derived IgG, and this attenuation could be reversed by IgG neutralization. These data demonstrate that neuron-derived IgG is protective of neurons against injury induced by complement and microglial activation. IgG appears to play an important role in maintaining the stability of the nervous system.

  6. Effects of sterilizing radiation dose on the amino acid composition of normal human Ig(G)

    International Nuclear Information System (INIS)

    Kaupert, N.L.; Mariano, E.E.

    1981-01-01

    In order to verify gamma radiation effect of 60 Co, samples of Normal human Ig(G) in a) pH 7 solutions with different concentrations, and b) in liophilized state, were irradiated. In both, the quali and quantitative amino acid compositions have been studied. No changes in amino acid composition were observed, for doses up to 10 Mrad delivered to the liophilized samples. Nevertheless, when 5 mg/ml and 10 mg/ml solutions of Ig(G) were irradiated with a 2 Mrad gamma dose, both were affected. The damage appeared in greater proportion in the samples with lower concentration. Cistine was the amino acid most damaged and the loss of methionine, proline histidine, arginine, tirosine and phenilalanine, decreased in this order. The analysis of the experimental data shows that liophilized human Ig(G) can be treated with doses higher than those required to achieve sterilization, without modifying its immunologic and primary proteic structure properties. Therefore, gamma sterilization feasibility has been proved for normal human Ig(G) only in the liophilized state. (author) [es

  7. Production and characterization of anti-human IgG F(ab')2 antibody fragment.

    Science.gov (United States)

    Valedkarimi, Zahra; Nasiri, Hadi; Aghebati-Maleki, Leili; Abdolalizadeh, Jalal; Esparvarinha, Mojghan; Majidi, Jafar

    2018-04-10

    In present study an optimized protocol for the separation of antibodies into antigen-binding fragments F(ab')2 using pepsin digestion was investigated. The production of these fragments is a consequential step in the development of medical research, treatment and diagnosis. For production of polyclonal antibody rabbit received antigen in four steps. The rabbit serum at 1/128000 dilution showed high absorbance in reaction with human IgG at the designed ELISA method. Rabbit IgG was purified by Ion-Exchange Chromatography (IEC) method. Purity was assessed by SDS-PAGE method. In non-reduced condition only one band was seen in about 150 kDa MW position and in reduced form, two bands were seen in 50 and 25 kDa MW positions. Rabbit IgG was digested by pepsin enzyme. The antibody fragments solution was applied to Gel filtration column to isolate the F(ab')2. Non-reduced SDS-PAGE for determining the purity of F(ab')2 fragment resulted in one band in 100 kDa corresponds to F(ab')2 fragment and a band in 150 kDa MW position corresponds to undigested IgG antibodies. The activities of FITC conjugated F(ab')2 fragment and commercial ones were compared using flowcytometry method. The activity results implied that the FITC conjugated- anti human F(ab')2 fragment worked as efficiently as the commercial one.

  8. Application of hanging drop technique to optimize human IgG formulations.

    Science.gov (United States)

    Li, Guohua; Kasha, Purna C; Late, Sameer; Banga, Ajay K

    2010-01-01

    The purpose of this work is to assess the hanging drop technique in screening excipients to develop optimal formulations for human immunoglobulin G (IgG). A microdrop of human IgG and test solution hanging from a cover slide and undergoing vapour diffusion was monitored by a stereomicroscope. Aqueous solutions of IgG in the presence of different pH, salt concentrations and excipients were prepared and characterized. Low concentration of either sodium/potassium phosphate or McIlvaine buffer favoured the solubility of IgG. Addition of sucrose favoured the stability of this antibody while addition of NaCl caused more aggregation. Antimicrobial preservatives were also screened and a complex effect at different buffer conditions was observed. Dynamic light scattering, differential scanning calorimetry and size exclusion chromatography studies were performed to further validate the results. In conclusion, hanging drop is a very easy and effective approach to screen protein formulations in the early stage of formulation development.

  9. Autophagy mediates cytotoxicity of human colorectal cancer cells treated with garcinielliptone FC.

    Science.gov (United States)

    Won, Shen-Jeu; Yen, Cheng-Hsin; Lin, Ting-Yu; Jiang-Shieh, Ya-Fen; Lin, Chun-Nan; Chen, Jyun-Ti; Su, Chun-Li

    2018-01-01

    The tautomeric pair of garcinielliptone FC (GFC) is a novel tautomeric pair of polyprenyl benzophenonoid isolated from the pericarps of Garcinia subelliptica Merr. (G. subelliptica, Clusiaceae), a tree with abundant sources of polyphenols. Our previous report demonstrated that GFC induced apoptosis on various types of human cancer cell lines including chemoresistant human colorectal cancer HT-29 cells. In the present study, we observed that many autophagy-related genes in GFC-treated HT-29 cells were up- and down-regulated using a cDNA microarray containing oncogenes and kinase genes. GFC-induced autophagy of HT-29 cells was confirmed by observing the formation of acidic vesicular organelles, LC3 puncta, and double-membrane autophagic vesicles using flow cytometry, confocal microscopy, and transmission electron microscopy, respectively. Inhibition of AKT/mTOR/P70S6K signaling as well as formation of Atg5-Atg12 and PI3K/Beclin-1 complexes were observed using Western blot. Administration of autophagy inhibitor (3-methyladenine and shRNA Atg5) and apoptosis inhibitor Z-VAD showed that the GFC-induced autophagy was cytotoxic form and GFC-induced apoptosis enhanced GFC-induced autophagy. Our data suggest the involvement of autophagy and apoptosis in GFC-induced anticancer mechanisms of human colorectal cancer. © 2017 Wiley Periodicals, Inc.

  10. Anti-coagulation effect of Fc fragment against anti-β2-GP1 antibodies in mouse models with APS.

    Science.gov (United States)

    Xie, Weidong; Zhang, Yaou; Bu, Cunya; Sun, Shijing; Hu, Shaoliang; Cai, Guoping

    2011-01-01

    Anti-beta (2)-glycoprotein I (anti-β2-GP1) is one of the important pathogenesis factors responsible for thrombosis formation in patients with antiphospholipid syndrome (APS). Administration of intravenous immunoglobulin (IVIg) is a common method used to inhibit the abnormal antibody levels and decrease the mortality of APS in emergency situations. We hypothesize that the Fc fragment of IgG is the molecular structure responsible for these effects. The present study investigates the beneficial effects of both recombinant and natural human Fc fragments of heterogeneous IgG against human anti-β2-GP1 antibodies in mouse models with APS. Results showed that both recombinant and natural human Fc fragments moderately but significantly decreased the levels of serum anti-β2-GP1 antibodies and had anti-coagulation effects in human β2-GP1-immunized mice. Furthermore, both recombinant and natural human Fc fragments inhibited thrombosis formation and decreased mortality in mouse models infused intravenously with human anti-β2GP1 antibodies from patients with APS. Findings suggest that the Fc fragment might be one of the active structural units of heterogeneous IgG. Thus, recombinant human Fc fragment administration may be a useful treatment for individuals with APS. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. 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.

  12. Cleavage of the interchain disulfide bonds in rituximab increases its affinity for FcγRIIIA.

    Science.gov (United States)

    Suzuki, Mami; Yamanoi, Ayaka; Machino, Yusuke; Kobayashi, Eiji; Fukuchi, Kaori; Tsukimoto, Mitsutoshi; Kojima, Shuji; Kohroki, Junya; Akimoto, Kazunori; Masuho, Yasuhiko

    2013-07-05

    The Fc region of human IgG1 mediates effector function via binding to Fcγ receptors and complement activation. The H and L chains of IgG1 antibodies are joined by four interchain disulfide bonds. In this study, these bonds within the therapeutic IgG1 rituximab (RTX) were cleaved either by mild reduction followed by alkylation or by mild S-sulfonation; consequently, two modified RTXs - A-RTX (alkylated) and S-RTX (S-sulfonated) - were formed, and both were almost as potent as unmodified RTX when binding CD20 antigen. Unexpectedly, each modified RTX had a higher binding affinity for FcγRIIIA (CD16A) than did unmodified RTX. However, S-RTX and A-RTX were each less potent than RTX in an assay of antibody-dependent cellular cytotoxicity (ADCC). In this ADCC assay, each modified RTX showed decreased secretion of granzyme B, but no change in perforin secretion, from effector cells. These results provide significant information on the structures within IgG1 that are involved in binding FcγRIIIA, and they may be useful in the development of therapeutic antagonists for FcγRIIIA. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Antigen-binding radioimmunoassays for human IgG antibodies to bovine ν-lactoglobulin

    International Nuclear Information System (INIS)

    Turner, M.W.; Paganelli, R.; Levinsky, R.J.; Williams, A.

    1983-01-01

    A double antibody antigen-binding assay for the detection of human IgG antibodies to the bovine milk allergen ν-lactoglobulin is described. The levels of such antibodies in patients with established cows' milk protein intolerance were significantly higher than the levels observed in a healthy control group (P<0.01). The assay showed excellent correlation with a solid phase antigen binding assay (rsub(s) = 0.8, P<0.001). (Auth.)

  14. External apical root resorption diagnosis by using FII human dentine fraction and salivary IGg.

    Science.gov (United States)

    Da-Costa, Tânia Maris Pedrini Soares; Hidalgo, Mirian Marubayashi; Consolaro, Alberto; Lima, Carlos Eduardo de Oliveira; Tanaka, Evelise Ono; Itano, Eiko Nakagawa

    2018-06-01

    External apical root resorption as a consequence of orthodontic treatment is an inflammatory pathological process that results in permanent loss of tooth structure from the root apex. This study aimed to investigate the diagnostic potential of human dentine fractions and salivary IgG in external apical root resorption. Saliva samples were collected from 10 patients before (T0) and after 3 (T3), 6 (T6) and 12 (T12) months of orthodontic treatment. The total dentinal extract, obtained from human third molars, was fractioned by gel filtration chromatography in three fractions denominated FI, FII and FIII. The root resorption analysis of the upper central incisors was performed by digital image subtraction method. Reactivity of salivary IgG to antigenic fractions of dentine was determined by enzyme-linked immunosorbent assay (Elisa). Regardless of treatment, FI dentin fraction with high MM (root resorptions were detected. Our results suggest that FII human dentine fraction and salivary IgG have potential to be used in diagnosis and monitoring of external apical root resorption. The development of a practical and accessible biochemical test using saliva and FII dentine fraction may help in the prevention of severe root resorption. Copyright © 2018. Published by Elsevier Masson SAS.

  15. Serological analysis of human IgG and IgE anti-insulin antibodies by solid-phase radioimmunoassays

    International Nuclear Information System (INIS)

    Hamilton, R.G.; Rendell, M.; Adkinson, N.F. Jr.

    1980-01-01

    A single solid-phase assay system which is useful for quantitative measurement of both IgG and IgE anti-insulin antibodies in human serum has been developed. Insulin-specific immunoglobulins are absorbed from human serum by excess quantities of insulin-agarose. After washes to remove unbound immunoglobulins, radioiodinated Staph A or rabbit anti-human IgE is added to detect bound IgG or IgE anbitodies, respectively

  16. Comparison of the chemical behaviour of humanized ACMS VS. Human IGG radiolabeled with 99mTc

    International Nuclear Information System (INIS)

    Rivero Santamaria, Alejandro; Zayas Crespo, Francisco; Mesa Duennas, Niurka; Castillo Vitloch, Adolfo J.

    2003-01-01

    The purpose of this work is to compare the chemical behaviour of humanized AcMs vs. human IgG radiolabeled with 99 mTc. to this end, 3 immunoglobulins were analyzed, the IgG (human), the humanized monoclonal antibody R3 (Acm-R3h) and the humanized monoclonal antibody T1. The results obtained reveal slight differences as regards the behaviour of theses immunoglobulins before the labelling with 99T c, which shows differences in the chemical behaviour of these proteins. Although in theory the modifications that are made to the AcMs in order to humanize them must not affect their chemical behaviour, the obtained data indicate that the conditions for their radiolabelling should not be extrapolated from other proteins; on the contrary, particular procedures should be elaborated for each AcM-h

  17. Postneonatal Mortality and Liver Changes in Cloned Pigs Associated with Human Tumor Necrosis Factor Receptor I-Fc and Human Heme Oxygenase-1 Overexpression

    Directory of Open Access Journals (Sweden)

    Geon A. Kim

    2017-01-01

    Full Text Available Soluble human tumor necrosis factor (shTNFRI-Fc and human heme oxygenase 1 (hHO-1 are key regulators for protection against oxidative and inflammatory injury for xenotransplantation. Somatic cells with more than 10 copy numbers of shTNFRI-Fc and hHO-1 were employed in somatic cell nuclear transfer to generate cloned pigs, thereby resulting in seven cloned piglets. However, produced piglets were all dead within 24 hours after birth. Obviously, postnatal death with liver apoptosis was reported in the higher copy number of shTNFRI-Fc and hHO-1 piglets. In liver, the transcript levels of ferritin heavy chain, light chain, transferrin, and inducible nitric oxide synthase were significantly highly expressed compared to those of lower copy number of shTNFRI-Fc and hHO-1 piglets (P<0.05. Also, H2O2 contents were increased, and superoxide dismutase was significantly lower in the higher copy number of shTNFRI-Fc and hHO-1 piglets (P<0.05. These results indicate that TNFRI-Fc and hHO-1 overexpression may apparently induce free iron in the liver and exert oxidative stress by enhancing reactive oxygen species production and block normal postneonatal liver metabolism.

  18. Utility of a human FcRn transgenic mouse model in drug discovery for early assessment and prediction of human pharmacokinetics of monoclonal antibodies

    Science.gov (United States)

    Avery, Lindsay B.; Wang, Mengmeng; Kavosi, Mania S.; Joyce, Alison; Kurz, Jeffrey C.; Fan, Yao-Yun; Dowty, Martin E.; Zhang, Minlei; Zhang, Yiqun; Cheng, Aili; Hua, Fei; Jones, Hannah M.; Neubert, Hendrik; Polzer, Robert J.; O'Hara, Denise M.

    2016-01-01

    ABSTRACT Therapeutic antibodies continue to develop as an emerging drug class, with a need for preclinical tools to better predict in vivo characteristics. Transgenic mice expressing human neonatal Fc receptor (hFcRn) have potential as a preclinical pharmacokinetic (PK) model to project human PK of monoclonal antibodies (mAbs). Using a panel of 27 mAbs with a broad PK range, we sought to characterize and establish utility of this preclinical animal model and provide guidance for its application in drug development of mAbs. This set of mAbs was administered to both hemizygous and homozygous hFcRn transgenic mice (Tg32) at a single intravenous dose, and PK parameters were derived. Higher hFcRn protein tissue expression was confirmed by liquid chromatography-high resolution tandem mass spectrometry in Tg32 homozygous versus hemizygous mice. Clearance (CL) was calculated using non-compartmental analysis and correlations were assessed to historical data in wild-type mouse, non-human primate (NHP), and human. Results show that mAb CL in hFcRn Tg32 homozygous mouse correlate with human (r2 = 0.83, r = 0.91, p PK studies, enhancement of the early selection of lead molecules, and ultimately a decrease in the time for a drug candidate to reach the clinic. PMID:27232760

  19. Increased levels of IgG antibodies against human HSP60 in patients with spondyloarthritis

    DEFF Research Database (Denmark)

    Hjelholt, Astrid; Carlsen, Thomas Gelsing; Deleuran, Bent Winding

    2013-01-01

    Introduction: Spondyloarthritis (SpA) comprises a heterogeneous group of inflammatory diseases, with strong association to human leukocyte antigen (HLA)-B27. SpA is suggested triggered by bacterial infection, and bacterial heat shock protein (HSP) seems to be a strong T cell antigen. Since...... against human HSP60, but not antibodies against bacterial HSP60, were elevated in the SpA group compared with the control group. Association between IgG3 antibodies against human HSP60 and BASMI was shown in HLA-B27+ patients. Only weak correlation between antibodies against bacterial and human HSP60...... was seen, and there was no indication of cross-reaction. Conclusion: These results suggest that antibodies against human HSP60 is associated with SpA, however, the theory that antibodies against human HSP60 is a specific part of the aetiology, through cross-reaction to bacterial HSP60, cannot be supported...

  20. Dynamics of Inter-heavy Chain Interactions in Human Immunoglobulin G (IgG) Subclasses Studied by Kinetic Fab Arm Exchange

    NARCIS (Netherlands)

    Rispens, Theo; Davies, Anna M.; Ooijevaar-de Heer, Pleuni; Absalah, Samira; Bende, Onno; Sutton, Brian J.; Vidarsson, Gestur; Aalberse, Rob C.

    2014-01-01

    Background: Fab arm exchange requires weak interactions between CH3 domains, such as in human IgG4. Results: CH3-CH3 interactions differ >1,000,000-fold between human subclasses and allotypes due to variations Lys/Asn-392, Val/Met-397, and Lys/Arg-409. Conclusion: For IgG2 and IgG3, but not IgG1,

  1. Human placenta: relative content of antibodies of different classes and subclasses (IgG1-IgG4) containing lambda- and kappa-light chains and chimeric lambda-kappa-immunoglobulins.

    Science.gov (United States)

    Lekchnov, Evgenii A; Sedykh, Sergey E; Dmitrenok, Pavel S; Buneva, Valentina N; Nevinsky, Georgy A

    2015-06-01

    The specific organ placenta is much more than a filter: it is an organ that protects, feeds and regulates the growth of the embryo. Affinity chromatography, ELISA, SDS-PAGE and matrix-assisted laser desorption ionization mass spectrometry were used. Using 10 intact human placentas deprived of blood, a quantitative analysis of average relative content [% of total immunoglobulins (Igs)] was carried out for the first time: (92.7), IgA (2.4), IgM (2.5), kappa-antibodies (51.4), lambda-antibodies (48.6), IgG1 (47.0), IgG2 (39.5), IgG3 (8.8) and IgG4 (4.3). It was shown for the first time that placenta contains sIgA (2.5%). In the classic paradigm, Igs represent products of clonal B-cell populations, each producing antibodies recognizing a single antigen. There is a common belief that IgGs in mammalian biological fluids are monovalent molecules having stable structures and two identical antigen-binding sites. However, similarly to human milk Igs, placenta antibodies undergo extensive half-molecule exchange and the IgG pool consists of 43.5 ± 15.0% kappa-kappa-IgGs and 41.6 ± 17.0% lambda-lambda-IgGs, while 15.0 ± 4.0% of the IgGs contained both kappa- and lambda-light chains. Kappa-kappa-IgGs and lambda-lambda-IgGs contained, respectively (%): IgG1 (47.7 and 34.4), IgG2 (36.3 and 44.5), IgG3 (7.4 and 11.8) and IgG4 (7.5 and 9.1), while chimeric kappa-lambda-IgGs consisted of (%): 43.5 IgG1, 41.0 IgG2, 5.6 IgG3 and 7.9 IgG4. Our data are indicative of the possibility of half-molecule exchange between placenta IgGs of various subclasses, raised against different antigens, which explains a very well-known polyspecificity and cross-reactivity of different human IgGs. © The Japanese Society for Immunology. 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Pyrosequencing for classification of human FcγRIIIA allotypes: a comparison with PCR-based techniques.

    Science.gov (United States)

    Matlawska-Wasowska, Ksenia; Gale, James M; Nickl, Christian K; Khalili, Parisa; Shirley, Brian; Wilson, Bridget S; Vasef, Mohammad A; Winter, Stuart S

    2014-12-01

    Surface-specific antigens expressed by hematopoietic cells are attractive targets for antibody-mediated immunotherapy. Monoclonal antibodies (mAbs) involve various mechanisms to eliminate target cells, including antibody-dependent cellular cytotoxicity (ADCC)- and phagocytosis (ADCP)-mediated killing through natural killer (NK) and macrophage effector cells bearing FcγRIIIA (CD16). The clinical efficacy of ADCC is particularly impacted by a single nucleotide polymorphism (SNP) found in the gene encoding FcγRIIIA (FCGR3A), which generates a variable distribution of the 158 V/V, F/V or F/F CD16 allotypes (F = phenylalanine, V = valine) in the normal human population. Currently, most patients are not screened for CD16 allotypes, creating the potential to include in their treatment a mAb-based therapy that may have limited benefit. Therefore, it is important to identify CD16 allotypes when considering mAb therapies that require ADCC/ADCP. The objective of this study was to develop a reliable PCR-based assay for classification of human FcγRIIIA allotypes. We studied 42 normal human subjects for the incidence of FcγRIIIA-158 polymorphisms using comparative molecular approaches. The results of our study showed 100% accuracy in genotyping by pyrosequencing. In contrast, nested PCR-based allele-specific restriction assay and quantitative PCR techniques proved to be relatively less sensitive and less specific in distinguishing variant genotypes. Since the efficacy of the mAb-based targeted immunotherapy may be highly dependent upon the CD16 polymorphism in a given individual, we recommend pyrosequencing for CD16 allotype testing.

  3. FcγRll: Characterisation of novel Fc receptor interactions and a new receptor form.

    OpenAIRE

    JESSICA CLAIRE ANANIA

    2018-01-01

    Leukocyte Fc receptors (FcR) bind to immunogloulins (Ig) to link the innate and humoral immune system to help balance the immune system and clear infections. We have characterised a novel FcR for IgG (FcγR) form, designated FcγRIIa3, which contains a 19 amino acid insert. This insert interacts with cytoskeletal structures allowing the receptor to be retained for longer periods of time at the cells surface upon activation, higher cell signalling which causes greater cellular activation. Theref...

  4. Chimeric immunoglobulin E reactive with tumor-associated antigen activates human Fc epsilon RI bearing cells

    NARCIS (Netherlands)

    Luiten, R. M.; Warnaar, S. O.; Schuurman, J.; Pasmans, S. G.; Latour, S.; Daëron, M.; Fleuren, G. J.; Litvinov, S. V.

    1997-01-01

    Crosslinking of immunoglobulin E molecules that are bound to the Fc epsilon receptors expressed on mast cells or basophils triggers activation of these cells, resulting in the development of a type I hypersensitivity. Targeting this potent immune reaction towards tumors by using IgE that reacts with

  5. Highly sensitive detection of human IgG using a novel bio-barcode assay combined with DNA chip technology

    International Nuclear Information System (INIS)

    Liu, Zhenbao; Zhou, Bo; Wang, Haiqing; Lu, Feng; Liu, Tianjun; Song, Cunxian; Leng, Xigang

    2013-01-01

    A simple and ultrasensitive detection of human IgG based on signal amplification using a novel bio-barcode assay and DNA chip technology was developed. The sensing platform was a sandwich system made up of antibody-modified magnetic microparticles (Ab-MMPs)/human IgG/Cy3-labeled single-stranded DNA and antibody-modified gold nanoparticles (Cy3-ssDNA-Ab-AuNPs). The MMPs (2.5 μm in diameter) modified with mouse anti-human IgG monoclonal-antibodies could capture human IgG and further be separated and enriched via a magnetic field. The AuNPs (13 nm in diameter) conjugated with goat anti-human IgG polyclonal-antibodies and Cy3-ssDNA could further combine with the human IgG/Ab-MMP complex. The Cy3-ssDNA on AuNPs was then released by TCEP to hybridize with the DNA chip, thus generating a detectable signal by the fluorescence intensity of Cy3. In order to improve detection sensitivity, a three-level cascaded signal amplification was developed: (1) The MMP enrichment as the first-level; (2) Large quantities of Cy3-ssDNA on AuNPs as the second-level; (3) The Cy3-ssDNA conjugate with DNA chip as the third-level. The highly sensitive technique showed an increased response of the fluorescence intensity to the increased concentration of human IgG through a detection range from 1 pg mL −1 to 10 ng mL −1 . This sensing technique could not only improve the detection sensitivity for the low concentration of human IgG but also present a robust and efficient signal amplification model. The detection method has good stability, specificity, and reproducibility and could be applied in the detection of human IgG in the real samples

  6. Highly sensitive detection of human IgG using a novel bio-barcode assay combined with DNA chip technology

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhenbao [Central South University, School of Pharmaceutical Sciences (China); Zhou, Bo, E-mail: zhoubo1771@163.com [The Affiliated Zhongda Hospital of Southeast University, Department of Gerontology (China); Wang, Haiqing; Lu, Feng; Liu, Tianjun; Song, Cunxian; Leng, Xigang, E-mail: lengxigyky@163.com [Institute of Biomedical Engineering, Chinese Academy of Medical Sciences and Peking Union Medical College (China)

    2013-09-15

    A simple and ultrasensitive detection of human IgG based on signal amplification using a novel bio-barcode assay and DNA chip technology was developed. The sensing platform was a sandwich system made up of antibody-modified magnetic microparticles (Ab-MMPs)/human IgG/Cy3-labeled single-stranded DNA and antibody-modified gold nanoparticles (Cy3-ssDNA-Ab-AuNPs). The MMPs (2.5 {mu}m in diameter) modified with mouse anti-human IgG monoclonal-antibodies could capture human IgG and further be separated and enriched via a magnetic field. The AuNPs (13 nm in diameter) conjugated with goat anti-human IgG polyclonal-antibodies and Cy3-ssDNA could further combine with the human IgG/Ab-MMP complex. The Cy3-ssDNA on AuNPs was then released by TCEP to hybridize with the DNA chip, thus generating a detectable signal by the fluorescence intensity of Cy3. In order to improve detection sensitivity, a three-level cascaded signal amplification was developed: (1) The MMP enrichment as the first-level; (2) Large quantities of Cy3-ssDNA on AuNPs as the second-level; (3) The Cy3-ssDNA conjugate with DNA chip as the third-level. The highly sensitive technique showed an increased response of the fluorescence intensity to the increased concentration of human IgG through a detection range from 1 pg mL{sup -1} to 10 ng mL{sup -1}. This sensing technique could not only improve the detection sensitivity for the low concentration of human IgG but also present a robust and efficient signal amplification model. The detection method has good stability, specificity, and reproducibility and could be applied in the detection of human IgG in the real samples.

  7. Highly sensitive detection of human IgG using a novel bio-barcode assay combined with DNA chip technology

    Science.gov (United States)

    Liu, Zhenbao; Zhou, Bo; Wang, Haiqing; Lu, Feng; Liu, Tianjun; Song, Cunxian; Leng, Xigang

    2013-09-01

    A simple and ultrasensitive detection of human IgG based on signal amplification using a novel bio-barcode assay and DNA chip technology was developed. The sensing platform was a sandwich system made up of antibody-modified magnetic microparticles (Ab-MMPs)/human IgG/Cy3-labeled single-stranded DNA and antibody-modified gold nanoparticles (Cy3-ssDNA-Ab-AuNPs). The MMPs (2.5 μm in diameter) modified with mouse anti-human IgG monoclonal-antibodies could capture human IgG and further be separated and enriched via a magnetic field. The AuNPs (13 nm in diameter) conjugated with goat anti-human IgG polyclonal-antibodies and Cy3-ssDNA could further combine with the human IgG/Ab-MMP complex. The Cy3-ssDNA on AuNPs was then released by TCEP to hybridize with the DNA chip, thus generating a detectable signal by the fluorescence intensity of Cy3. In order to improve detection sensitivity, a three-level cascaded signal amplification was developed: (1) The MMP enrichment as the first-level; (2) Large quantities of Cy3-ssDNA on AuNPs as the second-level; (3) The Cy3-ssDNA conjugate with DNA chip as the third-level. The highly sensitive technique showed an increased response of the fluorescence intensity to the increased concentration of human IgG through a detection range from 1 pg mL-1 to 10 ng mL-1. This sensing technique could not only improve the detection sensitivity for the low concentration of human IgG but also present a robust and efficient signal amplification model. The detection method has good stability, specificity, and reproducibility and could be applied in the detection of human IgG in the real samples.

  8. KIT of human polyclonal IGG for the I diagnostic of infectious processes

    International Nuclear Information System (INIS)

    Perera, Alejandro

    1997-01-01

    Early diagnosis of infections can be performed by using non-invasive techniques of Nuclear Medicine, even before appearing anatomical damage of the tissues. The main aim of the present work was to obtain a freeze-dried kit for direct labelling of human polyclonal IgG, for the detection of septic processes by scintigraphy. 99mT c-IgG labelling procedure was carried out by Schwarz method Its was obtained the best yields of 99m Tc using using sodium pyrophosphate decahydrate as a week chelating agent

  9. Antigen recognition by IgG4 antibodies in human trichinellosis

    Directory of Open Access Journals (Sweden)

    Pinelli E.

    2001-06-01

    Full Text Available The antibody isotype response to Trichinella spiralis excretory/secretory (ES products of muscle larva was examined using sera from patients with confirmed trichinellosis. Using Western blots we identify components of the ES antigen that are recognized by IgM and IgG antibodies. A 45 kDa component was strongly recognized by different antibody classes and subclasses. We observed a 45 kDa-specific lgG4 response that was detected exclusively using sera of patients with trichinellosis and not of patients with echinococcosis, filariasis, cysticercosis, ascariasis, strongyloidiasis or toxocariasis. These results are relevant for the diagnosis of human trichinellosis.

  10. 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

  11. The neonatal Fc receptor, FcRn, as a target for drug delivery and therapy.

    Science.gov (United States)

    Sockolosky, Jonathan T; Szoka, Francis C

    2015-08-30

    Immunoglobulin G (IgG)-based drugs are arguably the most successful class of protein therapeutics due in part to their remarkably long blood circulation. This arises from IgG interaction with the neonatal Fc receptor, FcRn. FcRn is the central regulator of IgG and albumin homeostasis throughout life and is increasingly being recognized as an important player in autoimmune disease, mucosal immunity, and tumor immune surveillance. Various engineering approaches that hijack or disrupt the FcRn-mediated transport pathway have been devised to develop long-lasting and non-invasive protein therapeutics, protein subunit vaccines, and therapeutics for treatment of autoimmune and infectious disease. In this review, we highlight the diverse biological functions of FcRn, emerging therapeutic opportunities, as well as the associated challenges of targeting FcRn for drug delivery and disease therapy. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Production and characterization of soluble human TNFRI-Fc and human HO-1(HMOX1) transgenic pigs by using the F2A peptide.

    Science.gov (United States)

    Park, Sol Ji; Cho, Bumrae; Koo, Ok Jae; Kim, Hwajung; Kang, Jung Taek; Hurh, Sunghoon; Kim, Su Jin; Yeom, Hye Jung; Moon, Joonho; Lee, Eun Mi; Choi, Ji Yei; Hong, Ju Ho; Jang, Goo; Hwang, Joing-Ik; Yang, Jaeseok; Lee, Byeong Chun; Ahn, Curie

    2014-06-01

    Generation of transgenic pigs for xenotransplantation is one of the most promising technologies for resolving organ shortages. Human heme oxygenase-1 (hHO-1/HMOX1) can protect transplanted organs by its strong anti-oxidative, anti-apoptotic, and anti-inflammatory effects. Soluble human TNFRI-Fc (shTNFRI-Fc) can inhibit the binding of human TNF-α (hTNF-α) to TNF receptors on porcine cells, and thereby, prevent hTNF-α-mediated inflammation and apoptosis. Herein, we successfully generated shTNFRI-Fc-F2A-HA-hHO-1 transgenic (TG) pigs expressing both shTNFRI-Fc and hemagglutinin-tagged-human heme oxygenase-1 (HA-hHO-1) by using an F2A self-cleaving peptide. shTNFRI-Fc and HA-hHO-1 transgenes containing the F2A peptide were constructed under the control of the CAG promoter. Transgene insertion and copy number in the genome of transgenic pigs was confirmed by polymerase chain reaction (PCR) and Southern blot analysis. Expressions of shTNFRI-Fc and HA-hHO-1 in TG pigs were confirmed using PCR, RT-PCR, western blot, ELISA, and immunohistochemistry. shTNFRI-Fc and HA-hHO-1 were expressed in various organs, including the heart, lung, and spleen. ELISA assays detected shTNFRI-Fc in the sera of TG pigs. For functional analysis, fibroblasts isolated from a shTNFRI-Fc-F2A-HA-hHO-1 TG pig (i.e., #14; 1 × 10(5) cells) were cultured with hTNF-α (20 ng/mL) and cycloheximide (10 μg/mL). The viability of shTNFRI-Fc-F2A-HA-hHO-1 TG pig fibroblasts was significantly higher than that of the wild type (wild type vs. shTNFRI-Fc-F2A-HA-hHO-1 TG at 24 h, 31.6 ± 3.2 vs. 60.4 ± 8.3 %, respectively; p hHO-1 TG pig fibroblasts was lower than that of the wild type pig fibroblasts (wild type vs. shTNFRI-Fc-F2A-HA-hHO-1 TG at 12 h, 812,452 ± 113,078 RLU vs. 88,240 ± 10,438 RLU, respectively; p hHO-1 TG pigs generated by the F2A self-cleaving peptide express both shTNFRI-Fc and HA-hHO-1 molecules, which provides protection against oxidative and inflammatory injury

  13. Identification of conformational epitopes for human IgG on Chemotaxis inhibitory protein of Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Furebring Christina

    2009-03-01

    Full Text Available Abstract Background The Chemotaxis inhibitory protein of Staphylococcus aureus (CHIPS blocks the Complement fragment C5a receptor (C5aR and formylated peptide receptor (FPR and is thereby a potent inhibitor of neutrophil chemotaxis and activation of inflammatory responses. The majority of the healthy human population has antibodies against CHIPS that have been shown to interfere with its function in vitro. The aim of this study was to define potential epitopes for human antibodies on the CHIPS surface. We also initiate the process to identify a mutated CHIPS molecule that is not efficiently recognized by preformed anti-CHIPS antibodies and retains anti-inflammatory activity. Results In this paper, we panned peptide displaying phage libraries against a pool of CHIPS specific affinity-purified polyclonal human IgG. The selected peptides could be divided into two groups of sequences. The first group was the most dominant with 36 of the 48 sequenced clones represented. Binding to human affinity-purified IgG was verified by ELISA for a selection of peptide sequences in phage format. For further analysis, one peptide was chemically synthesized and antibodies affinity-purified on this peptide were found to bind the CHIPS molecule as studied by ELISA and Surface Plasmon Resonance. Furthermore, seven potential conformational epitopes responsible for antibody recognition were identified by mapping phage selected peptide sequences on the CHIPS surface as defined in the NMR structure of the recombinant CHIPS31–121 protein. Mapped epitopes were verified by in vitro mutational analysis of the CHIPS molecule. Single mutations introduced in the proposed antibody epitopes were shown to decrease antibody binding to CHIPS. The biological function in terms of C5aR signaling was studied by flow cytometry. A few mutations were shown to affect this biological function as well as the antibody binding. Conclusion Conformational epitopes recognized by human antibodies

  14. A radiolabeled antiglobulin assay to identify human cervical mucus immunoglobulin (Ig) A and IgG antisperm antibodies

    International Nuclear Information System (INIS)

    Haas, G.G. Jr.; D'Cruz, O.J.

    1989-01-01

    Antisperm immunoglobulin (Ig) A and IgG antibodies in human cervical mucus (CM) were identified by a radiolabeled antiglobulin assay. Cervical mucus samples from fertile and infertile women were exposed to a 1:3,200 dilution of 2-mercaptoethanol (2-ME), and 5 micrograms of the solubilized CM protein were assayed for the presence of IgA and IgG antisperm and anti-Candida activity by the radiolabeled antiglobulin assay. Purified human secretory IgA and IgG exposed to 2-ME retained the molecular integrity and functional activity of the untreated antibody molecules. CM aliquots collected after high-performance liquid chromatography (HPLC) fractionation were assessed for antisperm antibody activity; antisperm antibody activity was retained in the appropriate IgA or IgG CM fractions. The incidence of CM antisperm antibodies was minimally affected when the radiolabeled antiglobulin assay was performed with a motile sperm population. Approximately 70% of the CM IgA antisperm antibodies were of the IgA1 subclass; CM IgG was primarily of the IgG4 subclass. When Candida antigen was substituted for sperm in the radiolabeled antiglobulin assay, the CM antisperm antibodies were found to be exclusively sperm-specific. These data indicate that the radiolabeled antiglobulin assay using 2-ME to extract CM antibodies is a specific method for the assay of antisperm antibodies in CM

  15. Hydrodynamic delivery of plasmid DNA encoding human FcγR-Ig dimers blocks immune-complex mediated inflammation in mice.

    Science.gov (United States)

    Shashidharamurthy, R; Machiah, D; Bozeman, E N; Srivatsan, S; Patel, J; Cho, A; Jacob, J; Selvaraj, P

    2012-09-01

    Therapeutic use and function of recombinant molecules can be studied by the expression of foreign genes in mice. In this study, we have expressed human Fcγ receptor-Ig fusion molecules (FcγR-Igs) in mice by administering FcγR-Ig plasmid DNAs hydrodynamically and compared their effectiveness with purified molecules in blocking immune-complex (IC)-mediated inflammation in mice. The concentration of hydrodynamically expressed FcγR-Igs (CD16A(F)-Ig, CD32A(R)-Ig and CD32A(H)-Ig) reached a maximum of 130 μg ml(-1) of blood within 24 h after plasmid DNA administration. The in vivo half-life of FcγR-Igs was found to be 9-16 days and western blot analysis showed that the FcγR-Igs were expressed as a homodimer. The hydrodynamically expressed FcγR-Igs blocked 50-80% of IC-mediated inflammation up to 3 days in a reverse passive Arthus reaction model. Comparative analysis with purified molecules showed that hydrodynamically expressed FcγR-Igs are more efficient than purified molecules in blocking IC-mediated inflammation and had a higher half-life. In summary, these results suggest that the administration of a plasmid vector with the FcγR-Ig gene can be used to study the consequences of blocking IC binding to FcγRs during the development of inflammatory diseases. This approach may have potential therapeutic value in treating IC-mediated inflammatory autoimmune diseases such as lupus, arthritis and autoimmune vasculitis.

  16. Human anti-rhesus D IgG1 antibody produced in transgenic plants

    DEFF Research Database (Denmark)

    Bouquin, Thomas; Thomsen, Mads; Nielsen, Leif Kofoed

    2002-01-01

    antigen, which is responsible for alloimmunization of RhD- mothers carrying an RhD+ fetus. Anti-RhD extracted from plants specifically reacted with RhD+ cells in antiglobulin technique, and elicited a respiratory burst in human peripheral blood mononuclear cells. Plant-derived antibody had equivalent......Transgenic plants represent an alternative to cell culture systems for producing cheap and safe antibodies for diagnostic and therapeutic use. To evaluate the functional properties of a 'plantibody', we generated transgenic Arabidopsis plants expressing full-length human IgG1 against the Rhesus D...... properties to CHO cell-produced anti-RhD antibody, indicating its potential usefulness in diagnostic and therapeutic programs....

  17. Indirect radioiodination of human IgG with N-succinimidyl-3-iodo[125I] benzoate

    International Nuclear Information System (INIS)

    Liu Zhenfeng; Wang Yongxian; Dong Mo; Zhou Wei; Xia Jiaoyun; Yin Duanzhi; Li Linfa

    2007-01-01

    The objective of this study was to develop an acylation method for the radioiodination of monoclonal antibodies that could decrease the loss of radioiodine in vivo. Preparation of N- succinimidyl-3-iodobenzoate(S 125 IB) from the organoth precursor, N-succinimidyl-3-(tri-n-bu- tylstannyl)benzoate(ATE) proceeds in more than 95% labelling yield, when the mass of ATE and NCS are respectively 25-100 μg and 10-20 μg, and the volume of PBS is 10-20 μL, and reaction time is 5 min. IgG is labeled using S 125 IB in up to 75% conjugation efficiency and with well retained immunoreactivity to sheep anti-human IgG. Hepama-1 is also labeled using S 125 IB in more than 75% conjugation efficiency. Paired-label biodistribution studies in normal mice demonstrate that thyroid uptake(a monitor of dehalogenation) of Hepama-1 labeled by S 125 IB method is up to 87.9 times lower than that of Hepama-1 labeled with Iodogen. This result suggests that S 125 IB offers significant advantages for labeling proteins, antibodies over other conventional methods for protein radioiodination. (authors)

  18. 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

  19. Combined roles of human IgG subclass, alternative complement pathway activation, and epitope density in the bactericidal activity of antibodies to meningococcal factor h binding protein.

    Science.gov (United States)

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

    2012-01-01

    Meningococcal vaccines containing factor H binding protein (fHbp) are in clinical development. fHbp binds human fH, which enables the meningococcus to resist complement-mediated bacteriolysis. Previously, we found that chimeric human IgG1 mouse anti-fHbp monoclonal antibodies (MAbs) had human complement-mediated bactericidal activity only if the MAb inhibited fH binding. Since IgG subclasses differ in their ability to activate complement, we investigated the role of human IgG subclasses on antibody functional activity. We constructed chimeric MAbs in which three different murine fHbp-specific binding domains were each paired with human IgG1, IgG2, or IgG3. Against a wild-type group B isolate, all three IgG3 MAbs, irrespective of their ability to inhibit fH binding, had bactericidal activity that was >5-fold higher than the respective IgG1 MAbs, while the IgG2 MAbs had the least activity. Against a mutant with increased fHbp expression, the anti-fHbp MAbs elicited greater C4b deposition (classical pathway) and greater bactericidal activity than against the wild-type strain, and the IgG1 MAbs had similar or greater activity than the respective IgG3 MAbs. The bactericidal activity against both wild-type and mutant strains also was dependent, in part, on activation of the alternative complement pathway. Thus, at lower epitope density in the wild-type strain, the IgG3 anti-fHbp MAbs had the greatest bactericidal activity. At a higher epitope density in the mutant, the IgG1 MAbs had similar or greater bactericidal activity than the IgG3 MAbs, and the activity was less dependent on the inhibition of fH binding than at a lower epitope density.

  20. Postneonatal Mortality and Liver Changes in Cloned Pigs Associated with Human Tumor Necrosis Factor Receptor I-Fc and Human Heme Oxygenase-1 Overexpression.

    Science.gov (United States)

    Kim, Geon A; Jin, Jun-Xue; Lee, Sanghoon; Taweechaipaisankul, Anukul; Oh, Hyun Ju; Hwang, Joing-Ik; Ahn, Curie; Saadeldin, Islam M; Lee, Byeong Chun

    2017-01-01

    Soluble human tumor necrosis factor (shTNFRI-Fc) and human heme oxygenase 1 (hHO-1) are key regulators for protection against oxidative and inflammatory injury for xenotransplantation. Somatic cells with more than 10 copy numbers of shTNFRI-Fc and hHO-1 were employed in somatic cell nuclear transfer to generate cloned pigs, thereby resulting in seven cloned piglets. However, produced piglets were all dead within 24 hours after birth. Obviously, postnatal death with liver apoptosis was reported in the higher copy number of shTNFRI-Fc and hHO-1 piglets. In liver, the transcript levels of ferritin heavy chain, light chain, transferrin, and inducible nitric oxide synthase were significantly highly expressed compared to those of lower copy number of shTNFRI-Fc and hHO-1 piglets ( P hHO-1 piglets ( P hHO-1 overexpression may apparently induce free iron in the liver and exert oxidative stress by enhancing reactive oxygen species production and block normal postneonatal liver metabolism.

  1. Malaria resistance genes are associated with the levels of IgG subclasses directed against Plasmodium falciparum blood-stage antigens in Burkina Faso

    Directory of Open Access Journals (Sweden)

    Afridi Sarwat

    2012-09-01

    Full Text Available Abstract Background HBB, IL4, IL12, TNF, LTA, NCR3 and FCGR2A polymorphisms have been associated with malaria resistance in humans, whereas cytophilic immunoglobulin G (IgG antibodies are thought to play a critical role in immune protection against asexual blood stages of the parasite. Furthermore, HBB, IL4, TNF, and FCGR2A have been associated with both malaria resistance and IgG levels. This suggests that some malaria resistance genes influence the levels of IgG subclass antibodies. Methods In this study, the effect of HBB, IL4, IL12, TNF, LTA, NCR3 and FCGR2A polymorphisms on the levels of IgG responses against Plasmodium falciparum blood-stage extract was investigated in 220 individuals living in Burkina Faso. The Pearson’s correlation coefficient among IgG subclasses was determined. A family-based approach was used to assess the association of polymorphisms with anti-P. falciparum IgG, IgG1, IgG2, IgG3 and IgG4 levels. Results After applying a multiple test correction, several polymorphisms were associated with IgG subclass or IgG levels. There was an association of i haemoglobin C with IgG levels; ii the FcγRIIa H/R131 with IgG2 and IgG3 levels; iii TNF-863 with IgG3 levels; iv TNF-857 with IgG levels; and, v TNF1304 with IgG3, IgG4, and IgG levels. Conclusion Taken together, the results support the hypothesis that some polymorphisms affect malaria resistance through their effect on the acquired immune response, and pave the way towards further comprehension of genetic control of an individual’s humoral response against malaria.

  2. Quantitation of Fc receptors and surface immunoglobulin is affected by cell isolation procedures using plasmagel and ficoll-hypaque.

    Science.gov (United States)

    Alexander, E L; Titus, J A; Segal, D M

    1978-01-01

    When mononuclear leukocytes are isolated directly from whole human blood using Ficoll-Hypaque or Plasmagel, cytophilic immunoglobulin is detected on cell surfaces. Upon incubation at 37 degrees C, this cell-associated immunoglobulin is shed slowly into the medium. However, when cells are prewashed in phosphate-buffered saline prior to isolation, they appear to be free of cytophilic immunoglobulin. Compared to prewashed cells, populations retaining cytophilic immunoglobulin on their surfaces demonstrate a decreased binding of soluble immune complexes and radiolabelled trimeric rabbit IgG. The data suggest that Ficoll-Hypaque and Plasmagel cause serum IgG to bind with abnormally high affinity to human mononuclear leukocytes, probably via Fc receptors. This artifact of preparation can lead to erroneous estimates of the numbers of cells bearing Fc receptors or intrinsic membrane immunoglobulin within a given population of cells and to an inaccurate assessment of the average number of Fc receptors per cell.

  3. Linear pharmacokinetic parameters for monoclonal antibodies are similar within a species and across different pharmacological targets: A comparison between human, cynomolgus monkey and hFcRn Tg32 transgenic mouse using a population-modeling approach.

    Science.gov (United States)

    Betts, Alison; Keunecke, Anne; van Steeg, Tamara J; van der Graaf, Piet H; Avery, Lindsay B; Jones, Hannah; Berkhout, Jan

    2018-04-10

    The linear pharmacokinetics (PK) of therapeutic monoclonal antibodies (mAbs) can be considered a class property with values that are similar to endogenous IgG. Knowledge of these parameters across species could be used to avoid unnecessary in vivo PK studies and to enable early PK predictions and pharmacokinetic/pharmacodynamic (PK/PD) simulations. In this work, population-pharmacokinetic (popPK) modeling was used to determine a single set of 'typical' popPK parameters describing the linear PK of mAbs in human, cynomolgus monkey and transgenic mice expressing the human neonatal Fc receptor (hFcRn Tg32), using a rich dataset of 27 mAbs. Non-linear PK was excluded from the datasets and a 2-compartment model was applied to describe mAb disposition. Typical human popPK estimates compared well with data from comparator mAbs with linear PK in the clinic. Outliers with higher than typical clearance were found to have non-specific interactions in an affinity-capture self-interaction nanoparticle spectroscopy assay, offering a potential tool to screen out these mAbs at an early stage. Translational strategies were investigated for prediction of human linear PK of mAbs, including use of typical human popPK parameters and allometric exponents from cynomolgus monkey and Tg32 mouse. Each method gave good prediction of human PK with parameters predicted within 2-fold. These strategies offer alternative options to the use of cynomolgus monkeys for human PK predictions of linear mAbs, based on in silico methods (typical human popPK parameters) or using a rodent species (Tg32 mouse), and call into question the value of completing extensive in vivo preclinical PK to inform linear mAb PK.

  4. The inhibitory effect of ionizing radiation on Fc and C3 receptors on mouse and human leukocytes, and the protective potential of human albumin

    International Nuclear Information System (INIS)

    Herrera, M.A.; Diaz-Perches, R.; Gutierrez, M.; Gamminio, E.; Liera, C.; Nieto, P.; Weiss-Steider, B.

    1990-01-01

    The effect that ionizing radiation has in vitro on Fc and C3 receptors was evaluated at various doses and measured by means of erythrocytes coated with antibody (EA) and erythrocytes coated with antibody and complement (EAC) rosettes on human peripheral blood leukocytes (PBL) and on mouse bone marrow cells (BMC) and PBL. We found that the number of cells with either EA and EAC rosettes decreased as the radiation doses increased, and that they were almost absent when the highest doses were employed. We obtained evidence that albumin is a natural source of radio-protection for Fc and C3 receptors, and we showed that by increasing the amount of this molecule we could completely protect receptors for EA and EAC in vitro. Finally, the possible therapeutic value of the administration of human albumin to patients undergoing radiotherapy is discussed

  5. N-Linked Glycosylation is an Important Parameter for Optimal Selection of Cell Lines Producing Biopharmaceutical Human IgG

    NARCIS (Netherlands)

    van Berkel, Patrick H. C.; Gerritsen, Jolanda; Perdok, Gerrard; Valbjorn, Jesper; Vink, Tom; van de Winkel, Jan G. J.; Parren, Paul W. H. I.

    2009-01-01

    We studied the variations in N-linked glycosylation of human IgG molecules derived from 105 different stable cell lines each expressing one of the six different antibodies. Antibody expression was based on glutamine synthetase selection technology in suspension growing CHO-KISV cells. The glycans

  6. 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

  7. Human IgG subclass antibodies to the 19 kilodalton carboxy ...

    African Journals Online (AJOL)

    IgG2 or IgG4 antibodies were virtually nonexistent. The cross-reactivity between the 4 sequence variants (E-KNG, E-TSR, Q-KNG and. Q-TSR) of MSP119 was confirmed; however, a minority of sera preferentially recognised the KNG but not the TSR variants. All 33 P. falciparum isolates from different parts ofm Uganda

  8. Fc-mediated immune precipitation. III. Visualization by electron microscopy

    DEFF Research Database (Denmark)

    Møller, NPH; Christiansen, Gunna

    1983-01-01

    with either rabbit anti-KLH IgG or anti-KLH F(ab')2 fragments. The Fc-Fc interactions were investigated by reacting these surface-adsorbed antibody-rich KLH immune complexes with soluble, antigen-rich ferritin-anti-ferritin complexes using either rabbit anti-ferritin IgG or the corresponding isomolar F(ab')2...... fragments as antibody. Fc-Fc interactions were indicated by the formation of clusters or ring structures of ferritin molecules, which were only seen when using KLH anti-KLH IgG and ferritin-anti-ferritin IgG complexes. When F(ab')2 fragments were used as antibody, no reaction between KLH anti-KLH complexes...

  9. LatY136F knock-in mouse model for human IgG4-related disease.

    Science.gov (United States)

    Yamada, Kazunori; Zuka, Masahiko; Ito, Kiyoaki; Mizuguchi, Keishi; Kakuchi, Yasushi; Onoe, Tamehito; Suzuki, Yasunori; Yamagishi, Masakazu; Izui, Shozo; Malissen, Marie; Malissen, Bernard; Kawano, Mitsuhiro

    2018-01-01

    The adaptor protein Linker for activation of T cell (LAT) is a key signaling hub used by the T cell antigen receptor. Mutant mice expressing loss-of-function mutations affecting LAT and including a mutation in which tyrosine 136 is replaced by a phenylalanine (LatY136F) develop lymphoproliferative disorder involving T helper type 2 effector cells capable of triggering a massive polyclonal B cell activation that leads to hypergammaglobulinemia G1 and E and to non-resolving inflammation and autoimmunity. The purpose of this study was to evaluate whether the phenotypes of LatY136F knock-in mice resemble the immunohistopathological features of immunoglobulin G4-related disease (IgG4-RD). LatY136F knock-in mice were sacrificed at 4-20 weeks of age, and pancreas, kidney, salivary gland and lung were obtained. All organs were stained with hematoxylin-eosin and with Azan for estimation of collagen in fibrosis, and the severity scores of inflammation and fibrosis were evaluated. Immunostainings were performed to analyze the types of infiltrating cells. In addition, the effects of corticosteroid treatment on the development of tissue lesions and serum levels of IgG1 were assessed. Tissue lesions characterized by inflammatory mononuclear cell infiltration and fibrosis were detected in pancreas, kidney, and salivary gland starting from 6 weeks of age. Immunostainings showed pronounced infiltration of plasma cells, CD4-positive T cells, and macrophages. Infiltrating plasma cells predominantly expressed IgG1. The extent of inflammation in pancreas and salivary glands was markedly reduced by corticosteroid treatment. LatY136F knock-in mice displayed increased production of Th2-type IgG1 (a homologue of human IgG4) and developed multiple organ tissue lesions reminiscent of those seen in patients with IgG4-RD. Moreover, the development of these tissue lesions was highly sensitive to corticosteroid treatment like in IgG4-RD. For these reasons we consider the LatY136F knock-in mouse

  10. Dulaglutide, a long-acting GLP-1 analog fused with an Fc antibody fragment for the potential treatment of type 2 diabetes

    DEFF Research Database (Denmark)

    Jimenez-Solem, Espen; Rasmussen, Mette H; Christensen, Mikkel

    2010-01-01

    Dulaglutide (LY-2189265) is a novel, long-acting glucagon-like peptide 1 (GLP-1) analog being developed by Eli Lilly for the treatment of type 2 diabetes mellitus (T2DM). Dulaglutide consists of GLP-1(7-37) covalently linked to an Fc fragment of human IgG4, thereby protecting the GLP-1 moiety from...

  11. Scintigraphy with 99mTc labelled polyclonal human IgG in rheumatoid arthritis patients

    International Nuclear Information System (INIS)

    Stanchev, V.; Batalov, A.; Atanasov, A.

    1999-01-01

    The study design to assess the diagnostic relevance of scintigraphy with 99m Tc labelled polyclonal human IgG (HIG) for detecting active synovitis in rheumatoid arthritis patients. Fifteen patients presenting rheumatoid arthritis and 3 healthy volunteers are studied on digital camera (Diacam, Siemens). Following iv injection of 500 MBq 99m Tc - HIG, a 3- phase scintigraphy of the knee joints is performed and 4 hours later multiple planar views of the peripheral joint are recorded. Scintigraphic data are comparatively studied with the clinical indicators pointing to active synovitis - joint swellings and pain. Markedly expressed 99m Tc - HIG uptake is noted in joints apparently the most actively involved in the arthritis process clinically, whereas most of the joints without evidence of active synovitis revealed background activity only. The obtained scintigraphic results correlate strongly with the clinical indicator joint swelling (93.2%), and somewhat less with the presence of pain (81.5%). 13.5 per cent of the joints without clinically detectable swelling and 25.6% those free of pain are HIG-positive. 99m Tc - HIG scintigraphy is a highly sensitive noninvasive method of detecting active synovitis, promoting objective assessment of the joint inflammatory process in the course of treatment and follow-up study of rheumatoid arthritis patients

  12. NRG1-Fc improves metabolic health via dual hepatic and central action.

    Science.gov (United States)

    Zhang, Peng; Kuang, Henry; He, Yanlin; Idiga, Sharon O; Li, Siming; Chen, Zhimin; Yang, Zhao; Cai, Xing; Zhang, Kezhong; Potthoff, Matthew J; Xu, Yong; Lin, Jiandie D

    2018-03-08

    Neuregulins (NRGs) are emerging as an important family of signaling ligands that regulate glucose and lipid homeostasis. NRG1 lowers blood glucose levels in obese mice, whereas the brown fat-enriched secreted factor NRG4 protects mice from high-fat diet-induced insulin resistance and hepatic steatosis. However, the therapeutic potential of NRGs remains elusive, given the poor plasma half-life of the native ligands. Here, we engineered a fusion protein using human NRG1 and the Fc domain of human IgG1 (NRG1-Fc) that exhibited extended half-life in circulation and improved potency in receptor signaling. We evaluated its efficacy in improving metabolic parameters and dissected the mechanisms of action. NRG1-Fc treatment triggered potent AKT activation in the liver, lowered blood glucose, improved insulin sensitivity, and suppressed food intake in obese mice. NRG1-Fc acted as a potent secretagogue for the metabolic hormone FGF21; however, the latter was largely dispensable for its metabolic effects. NRG1-Fc directly targeted the hypothalamic POMC neurons to promote membrane depolarization and increase firing rate. Together, NRG1-Fc exhibits improved pharmacokinetic properties and exerts metabolic benefits through dual inhibition of hepatic gluconeogenesis and caloric intake.

  13. Fc-fusion Proteins in Therapy: An Updated View.

    Science.gov (United States)

    Jafari, Reza; Zolbanin, Naime M; Rafatpanah, Houshang; Majidi, Jafar; Kazemi, Tohid

    2017-01-01

    Fc-fusion proteins are composed of Fc region of IgG antibody (Hinge-CH2-CH3) and a desired linked protein. Fc region of Fc-fusion proteins can bind to neonatal Fc receptor (FcRn) thereby rescuing it from degradation. The first therapeutic Fc-fusion protein was introduced for the treatment of AIDS. The molecular designing is the first stage in production of Fc-fusion proteins. The amino acid residues in the Fc region and linked protein are very important in the bioactivity and affinity of the fusion proteins. Although, therapeutic monoclonal antibodies are the top selling biologics but the application of therapeutic Fc-fusion proteins in clinic is in progress and among these medications Etanercept is the most effective in therapy. At present, eleven Fc-fusion proteins have been approved by FDA. There are novel Fc-fusion proteins which are in pre-clinical and clinical development. In this article, we review the molecular and biological characteristics of Fc-fusion proteins and then further discuss the features of novel therapeutic Fc-fusion proteins. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  14. Human IgG is produced in a pro-form that requires clipping of C-terminal lysines for maximal complement activation

    DEFF Research Database (Denmark)

    van den Bremer, E. T. J.; Beurskens, F. J.; Voorhorst, M.

    2015-01-01

    Human IgG is produced with C-terminal lysines that are cleaved off in circulation. The function of this modification was unknown and generally thought not to affect antibody function. We recently reported that efficient C1q binding and complement-dependent cytotoxicity (CDC) requires IgG hexameri...

  15. [Eukaryotic Expression and Immunogenic Research of Recombination Ebola Virus Membrane Protein Gp-Fc].

    Science.gov (United States)

    Zhang, Xiaoguang; Yang, Ren; Wang, Jiao; Wang, Xuan; Hou, Mieling; An, Lina; Zhu, Ying; Cao, Yuxi; Zeng, Yi

    2016-01-01

    We used 293 cells to express the recombinant membrane protein of the Ebola virus. Then, the immunogenicity of the recombinant protein was studied by immunized BALB/c mice. According to the codon use frequency of humans, the gene encoding the extracellular domain of the Ebola virus membrane protein was optimized, synthesized, and inserted into the eukaryotic expression plasmid pXG-Fc to construct the human IgG Fc and Ebola GP fusion protein expression plasmid pXG-modGP-Fc. To achieve expression, the fusion protein expression vector was transfected into high-density 293 cells using transient transfection technology. The recombinant protein was purified by protein A affinity chromatography. BALB/c mice were immunized with the purified fusion protein, and serum antibody titers evaluated by an indirect enzyme-linked immunosorbent assay (ELISA). Purification and analyses of the protein revealed that the eukaryotic expression vector could express the recombinant protein GP-Fc effectively, and that the recombinant protein in the supernatant of the cell culture was present as a dimer. After immunization with the purified recombinant protein, a high titer of antigen-specific IgG could be detected in the serum of immunized mice by indirect ELISA, showing that the recombinant protein had good immunogenicity. These data suggest that we obtained a recombinant protein with good immunogenicity. Our study is the basis for development of a vaccine against the Ebola virus and for screening of monoclonal antibodies.

  16. A Unique Report: Development of Super Anti-Human IgG Monoclone with Optical Density Over Than 3

    OpenAIRE

    Aghebati Maleki, Leili; Baradaran, Behzad; Abdolalizadeh, Jalal; Ezzatifar, Fatemeh; Majidi, Jafar

    2013-01-01

    Purpose: Monoclonal antibodies and related conjugates are key reagents used in biomedical researches as well as, in treatment, purification and diagnosis of infectious and non- infectious diseases. Methods: Balb/c mice were immunized with purified human IgG. Spleen cells of the most immune mouse were fused with SP2/0 in the presence of Poly Ethylene Glycol (PEG). Supernatant of hybridoma cells was screened for detection of antibody by ELISA. Then, the sample was assessed for cross-reactivity ...

  17. Endothelial cells the site of the regulation of IgG LEVEL by salvaging and transcytosis of immunoglobulin

    International Nuclear Information System (INIS)

    Antohe, Felicia; Radulescu, Luminita; Simionescu, Maya; Ghetie, Victor

    2002-01-01

    ), transferrin (Tavassoli et al 1986), ceruloplasmin (Tarsio et al 1987), transcobalamin II (Soda et al 1985) the complex biochemical events taking place at the blood-vessel wall interface are not fully understood. This is the case of IgG transfer from mother to fetus. The process is thought to involve specific receptors that bind to the Fc region of the IgG molecule namely the MHC class I related receptor FcRn (Brambel 1970, Rodewald 1980). Until now, the reported data showed that FcRn was occasional (Kristofersen et al 1996) low level (Leach et al 1996) or not at all expressed (Simister et al 1996) in fetal endothelial cells. Taking advantage of the successful isolation and cultivation of microvascular endothelial cells from human term placenta (Jinga V et al 1999) we can now appropriately investigate the presence, distribution and function of FcRn in placental endothelial cells.Transfer of maternal gammaglobulin (IgG) to the fetus provides the neonate with humoral immunity during early lifetime. The mechanism of selective transport of IgG from the placental stroma to the lumen of the fetal blood vessels has not been elucidated, yet. It was postulated that the specific transport as well as the regulation of IgG concentration in the blood, involves the MHC class I related receptor - FcRn - for the Fc domain of IgG. We questioned whether, human placental endothelial cells (HPEC) express FcRn, and if present, whether it is in a functionally active form. The experiments were performed on cultured HPEC; as positive control, cultured human trophoblastic cells (JEG3) and mouse SV-40 transformed EC line (SVEC) shown to express mRNA for the human FcRn, were used. The double chamber system. The permeability coefficient expression of FcRn was tested by indirect immunofluorescence. The role of FcRn was assessed on HPEC grown on filters in a double chamber system by quantifying the transcytosis of [ 125 I]-human IgG or [ 125 I]-rF(ab') 2 fragments (as control) from the apical to

  18. Biotin-avidin sandwich elisa with specific human isotypes IgG1 and IgG4 for Culicidae mosquito blood meal identification from an epizootic yellow fever area in Brazil

    Directory of Open Access Journals (Sweden)

    AM Marassá

    2009-01-01

    Full Text Available With a view toward investigating the feeding behavior of Culicidae mosquitoes from an area of epizootic yellow fever transmission in the municipalities of Garruchos and Santo Antônio das Missões, Rio Grande do Sul State, Brazil, specimens were collected by aspiration from September 2005 to April 2007. The engorged females were submitted to blood meal identification by enzyme-linked immunosorbent assay (ELISA. A total of 142 blood-engorged samples were examined for human or monkey blood through species-specific IgG. Additional tests for specificity utilizing isotypes IgG1 and IgG4 of human monoclonal antibodies showed that only anti-human IgG1 was effective in recognizing blood meals of human origin. The results indicated a significant difference (p = 0.027 in detection patterns in samples of Haemagogus leucocelaenus recorded from human blood meals at Santo Antônio das Missões, which suggests some degree of exposure, since it was an area where epizootic outbreaks have been reported.

  19. The Emerging Importance of IgG Fab Glycosylation in Immunity.

    Science.gov (United States)

    van de Bovenkamp, Fleur S; Hafkenscheid, Lise; Rispens, Theo; Rombouts, Yoann

    2016-02-15

    Human IgG is the most abundant glycoprotein in serum and is crucial for protective immunity. In addition to conserved IgG Fc glycans, ∼15-25% of serum IgG contains glycans within the variable domains. These so-called "Fab glycans" are primarily highly processed complex-type biantennary N-glycans linked to N-glycosylation sites that emerge during somatic hypermutation. Specific patterns of Fab glycosylation are concurrent with physiological and pathological conditions, such as pregnancy and rheumatoid arthritis. With respect to function, Fab glycosylation can significantly affect stability, half-life, and binding characteristics of Abs and BCRs. Moreover, Fab glycans are associated with the anti-inflammatory activity of IVIgs. Consequently, IgG Fab glycosylation appears to be an important, yet poorly understood, process that modulates immunity. Copyright © 2016 by The American Association of Immunologists, Inc.

  20. Homogeneous immunoassay for human IgG using oriented hen egg IgY immobilized on gold sol nanoparticles

    International Nuclear Information System (INIS)

    Yeritsyan, H.E.; Gasparyan, V.K.

    2012-01-01

    Homogeneous immunoassays using (red) gold nanoparticles represent an attractive detection scheme because of the option of photometric readout. We have applied oriented immobilization of hen egg immunoglobulin Y (IgY) on gold nanoparticles when developing a homogeneous immunoassay for human IgG. In oriented immobilization, as opposed to random immobilization, the antigen binding capabilities of the antibodies are retained. It is shown that such immunoassay has significantly better sensitivity in comparison with methods based on conventional immobilization of affinity-purified antibodies. It is also shown that hen egg IgY is better suited than rabbit antibodies, because much more antibody can be immobilized on gold nanoparticles without any destabilization, probably because of the more acidic nature of these antibodies. In addition, hen egg IgY can be supplied in higher quantity and can be prepared more easily than IgG from rabbits. Bleeding and slaughtering of animals is not needed. The assay presented here has a wide detection range (30-500 ng. mL -1 ) and a limit of detection as low as 30 ng. mL -1 of human IgG. (author)

  1. Differential antibody isotype reactivity to specific antigens in human lymphatic filariasis: gp15/400 preferentially induces immunoglobulin E (IgE), IgG4, and IgG2

    NARCIS (Netherlands)

    Yazdanbakhsh, M.; Paxton, W. A.; Brandenburg, A.; van Ree, R.; Lens, M.; Partono, F.; Maizels, R. M.; Selkirk, M. E.

    1995-01-01

    Lymphatic filarial infection in humans is associated with a strong skewing of the immune response towards the TH2 arm, with prominent interleukin 4-producing cells and elevated levels of immunoglobulin G4 (IgG4) and IgE antibodies in peripheral blood. To determine how such a generalized TH2

  2. Specificity and effector functions of human RSV-specific IgG from bovine milk

    NARCIS (Netherlands)

    Hartog, den C.G.; Jacobino, S.; Bont, L.; Cox, L.; Ulfman, L.H.; Leusen, J.H.W.; Neerven, van R.J.J.

    2014-01-01

    Background Respiratory syncytial virus (RSV) infection is the second most important cause of death in the first year of life, and early RSV infections are associated with the development of asthma. Breastfeeding and serum IgG have been shown to protect against RSV infection. Yet, many infants depend

  3. Prophylactic anti-D preparations display variable decreases in Fc-fucosylation of anti-D.

    NARCIS (Netherlands)

    Kapur, R.; Della Valle, L.; Verhagen, O.J.; Hipgrave Ederveen, A.; Ligthart, P.; de Haas, M.; Kumpel, B.; Wuhrer, M.; van der Schoot, C.E.; Vidarsson, G.

    2015-01-01

    Background RhIG is obtained from hyperimmunized healthy anti-D donors (HIDs) boosted with D+ red blood cells (RBCs). One hypothesis for its mechanism of action is fast clearance of opsonized D+ RBCs through Fcγ receptor (FcγR)III. Levels of immunoglobulin (Ig)G Fc-fucosylation influence interactions

  4. Prophylactic anti-D preparations display variable decreases in Fc-fucosylation of anti-D

    NARCIS (Netherlands)

    Kapur, Rick; Della Valle, Luciana; Verhagen, Onno J. H. M.; Hipgrave Ederveen, Agnes; Ligthart, Peter; de Haas, Masja; Kumpel, Belinda; Wuhrer, Manfred; van der Schoot, C. Ellen; Vidarsson, Gestur

    2015-01-01

    RhIG is obtained from hyperimmunized healthy anti-D donors (HIDs) boosted with D+ red blood cells (RBCs). One hypothesis for its mechanism of action is fast clearance of opsonized D+ RBCs through Fcγ receptor (FcγR)III. Levels of immunoglobulin (Ig)G Fc-fucosylation influence interactions with

  5. Monovalent IgG4 molecules

    Science.gov (United States)

    Wilkinson, Ian C.; Fowler, Susan B.; Machiesky, LeeAnn; Miller, Kenneth; Hayes, David B.; Adib, Morshed; Her, Cheng; Borrok, M. Jack; Tsui, Ping; Burrell, Matthew; Corkill, Dominic J.; Witt, Susanne; Lowe, David C.; Webster, Carl I.

    2013-01-01

    Antibodies have become the fastest growing class of biological therapeutics, in part due to their exquisite specificity and ability to modulate protein-protein interactions with a high biological potency. The relatively large size and bivalency of antibodies, however, limits their use as therapeutics in certain circumstances. Antibody fragments, such as single-chain variable fragments and antigen binding-fragments, have emerged as viable alternatives, but without further modifications these monovalent formats have reduced terminal serum half-lives because of their small size and lack of an Fc domain, which is required for FcRn-mediated recycling. Using rational engineering of the IgG4 Fc domain to disrupt key interactions at the CH3-CH3 interface, we identified a number of point mutations that abolish Fc dimerization and created half-antibodies, a novel monovalent antibody format that retains a monomeric Fc domain. Introduction of these mutations into an IgG1 framework also led to the creation of half-antibodies. These half-antibodies were shown to be soluble, thermodynamically stable and monomeric, characteristics that are favorable for use as therapeutic proteins. Despite significantly reduced FcRn binding in vitro, which suggests that avidity gains in a dimeric Fc are critical to optimal FcRn binding, this format demonstrated an increased terminal serum half-life compared with that expected for most alternative antibody fragments. PMID:23567207

  6. NEW ROLES FOR FC RECEPTORS IN NEURODEGENERATION-THE IMPACT ON IMMUNOTHERAPY FOR ALZHEIMER’S DISEASE

    Directory of Open Access Journals (Sweden)

    James P. Fuller

    2014-08-01

    Full Text Available There are an estimated 18 million Alzheimer’s disease (AD sufferers worldwide and with no disease modifying treatment currently available, development of new therapies represents an enormous unmet clinical need. AD is characterised by episodic memory loss followed by severe cognitive decline and is associated with many neuropathological changes. AD is characterised by deposits of amyloid beta (Aβ, neurofibrillary tangles, and neuroinflammation. Active immunisation or passive immunisation against Aβ leads to the clearance of deposits in transgenic mice expressing human Aβ. This clearance is associated with reversal of associated cognitive deficits, but these results have failed to translate to humans, with both active and passive immunotherapy failing to improve memory loss. One explanation for these observations is that certain anti-Aβ antibodies mediate damage to the cerebral vasculature limiting the top dose and potentially reducing efficacy. Fc gamma receptors (Fcγ are a family of immunoglobulin like receptors which bind to the Fc portion of IgG, and mediate the response of effector cells to immune complexes. Data from both mouse and human studies suggest that cross-linking Fc receptors by therapeutic antibodies and the subsequent pro-inflammatory response mediates the vascular side effects seen following immunotherapy. Increasing evidence is emerging that Fc receptor expression on CNS resident cells, including microglia and neurons, is increased during aging and functionally involved in the pathogenesis of age-related neurodegenerative diseases. We propose that increased expression and ligation of Fc receptors in the CNS, either by endogenous IgG or therapeutic antibodies, has the potential to induce vascular damage and exacerbate neurodegeneration. To produce safe and effective immunotherapies for AD and other neurodegenerative diseases it will be vital to understand the role of Fc receptors in the healthy and diseased brain.

  7. The herpes virus Fc receptor gE-gI mediates antibody bipolar bridging to clear viral antigens from the cell surface.

    Directory of Open Access Journals (Sweden)

    Blaise Ndjamen

    2014-03-01

    Full Text Available The Herpes Simplex Virus 1 (HSV-1 glycoprotein gE-gI is a transmembrane Fc receptor found on the surface of infected cells and virions that binds human immunoglobulin G (hIgG. gE-gI can also participate in antibody bipolar bridging (ABB, a process by which the antigen-binding fragments (Fabs of the IgG bind a viral antigen while the Fc binds to gE-gI. IgG Fc binds gE-gI at basic, but not acidic, pH, suggesting that IgG bound at extracellular pH by cell surface gE-gI would dissociate and be degraded in acidic endosomes/lysosomes if endocytosed. The fate of viral antigens associated with gE-gI-bound IgG had been unknown: they could remain at the cell surface or be endocytosed with IgG. Here, we developed an in vitro model system for ABB and investigated the trafficking of ABB complexes using 4-D confocal fluorescence imaging of ABB complexes with transferrin or epidermal growth factor, well-characterized intracellular trafficking markers. Our data showed that cells expressing gE-gI and the viral antigen HSV-1 gD endocytosed anti-gD IgG and gD in a gE-gI-dependent process, resulting in lysosomal localization. These results suggest that gE-gI can mediate clearance of infected cell surfaces of anti-viral host IgG and viral antigens to evade IgG-mediated responses, representing a general mechanism for viral Fc receptors in immune evasion and viral pathogenesis.

  8. Cloning of pCDNA3-IgG4 and pQE-2-IgG4 human hinge region ...

    African Journals Online (AJOL)

    GREGORY

    2011-12-16

    Dec 16, 2011 ... diseases and in allergy-related immunoassays, thus, anti-hIgG4 antibody is of interest in the development of ... pQE-2-. IgG4 will be used for protein expression in M15 prokaryotic .... Solution conformation of wild-type and ...

  9. Highly sensitive electrochemical immunoassay for human IgG using double-encoded magnetic redox-active nanoparticles

    International Nuclear Information System (INIS)

    Tang, D.; Tang, J.; Su, B.; Chen, H.; Chen, G.; Huang, J.

    2010-01-01

    A new sandwich-type electrochemical immunoassay was developed for the detection of human IgG using doubly-encoded and magnetic redox-active nanoparticles as recognition elements on the surface of a glassy carbon electrode modified with anti-IgG on nanogold particles. The recognition elements were synthesized by coating magnetic Fe3O4 nanoparticles with Prussian blue nanoparticles and then covered with peroxidase-labeled anti-IgG antibodies (POx-anti-IgG) on Prussian blue nanoparticles. The immunoelectrode displays very good electrochemical properties towards detection of IgG via using double-encoded magnetic redox-active nanoparticles as trace and hydrogen peroxide as enzyme substrate. Its limit of detection (10 pmol.L -1 ) is 10-fold better than that of using plain POx-anti-IgG secondary antibodies. The method was applied to the detection of IgG in serum samples, and an excellent correspondence with the reference values was found. (author)

  10. A Unique Report: Development of Super Anti-Human IgG Monoclone with Optical Density Over Than 3

    Directory of Open Access Journals (Sweden)

    Leili Aghebati Maleki

    2013-08-01

    Full Text Available Purpose: Monoclonal antibodies and related conjugates are key reagents used in biomedical researches as well as, in treatment, purification and diagnosis of infectious and non- infectious diseases. Methods: Balb/c mice were immunized with purified human IgG. Spleen cells of the most immune mouse were fused with SP2/0 in the presence of Poly Ethylene Glycol (PEG. Supernatant of hybridoma cells was screened for detection of antibody by ELISA. Then, the sample was assessed for cross-reactivity with IgM & IgA by ELISA and confirmed by immunoblotting. The subclasses of the selected mAbs were determined. The best clone was injected intraperitoneally to some pristane-injected mice. Anti-IgG mAb was purified from the animals' ascitic fluid by Ion exchange chromatography and then, mAb was conjugated with HRP. Results: In the present study, over than 50 clones were obtained that 1 clone had optical density over than 3. We named this clone as supermonoclone which was selected for limiting dilution. The result of the immunoblotting, showed sharp band in IgG position and did not show any band in IgM&IgA position. Conclusion: Based on the findings of this study, the conjugated monoclonal antibody could have application in diagnosis of infectious diseases like Toxoplasmosis, Rubella and IgG class of other infectious and non- infectious diseases.

  11. A Unique Report: Development of Super Anti-Human IgG Monoclone with Optical Density Over Than 3

    Science.gov (United States)

    Aghebati Maleki, Leili; Baradaran, Behzad; Abdolalizadeh, Jalal; Ezzatifar, Fatemeh; Majidi, Jafar

    2013-01-01

    Purpose: Monoclonal antibodies and related conjugates are key reagents used in biomedical researches as well as, in treatment, purification and diagnosis of infectious and non- infectious diseases. Methods: Balb/c mice were immunized with purified human IgG. Spleen cells of the most immune mouse were fused with SP2/0 in the presence of Poly Ethylene Glycol (PEG). Supernatant of hybridoma cells was screened for detection of antibody by ELISA. Then, the sample was assessed for cross-reactivity with IgM & IgA by ELISA and confirmed by immunoblotting. The subclasses of the selected mAbs were determined. The best clone was injected intraperitoneally to some pristane-injected mice. Anti-IgG mAb was purified from the animals' ascitic fluid by Ion exchange chromatography and then, mAb was conjugated with HRP. Results: In the present study, over than 50 clones were obtained that 1 clone had optical density over than 3. We named this clone as supermonoclone which was selected for limiting dilution. The result of the immunoblotting, showed sharp band in IgG position and did not show any band in IgM&IgA position. Conclusion: Based on the findings of this study, the conjugated monoclonal antibody could have application in diagnosis of infectious diseases like Toxoplasmosis, Rubella and IgG class of other infectious and non- infectious diseases. PMID:24312857

  12. Glucagon-like Peptide 1 Conjugated to Recombinant Human Serum Albumin Variants with Modified Neonatal Fc Receptor Binding Properties. Impact on Molecular Structure and Half-Life

    DEFF Research Database (Denmark)

    Bukrinski, Jens T.; Sønderby, Pernille; Antunes, Filipa

    2017-01-01

    Glucagon-like peptide 1 (GLP-1) is a small incretin hormone stimulated by food intake, resulting in an amplification of the insulin response. Though interesting as a drug candidate for the treatment of type 2 diabetes mellitus, its short plasma half-life of less than 3 minutes limits its clinical...... use. A strategy to extend the half-life of GLP-1 utilizes the long half-life of human serum albumin (HSA) by combining the two via chemical conjugation or genetic fusion. HSA has a plasma half-life of around 21 days owing to its interaction with the neonatal Fc receptor (FcRn) expressed in endothelial...... with the available structural information on the FcRn and GLP-1 receptor (GLP-1R) obtained from X-ray crystallography, we can explain the observed in-vitro and in-vivo behaviour. We conclude that the conjugation of GLP-1 to rHSA does not affect the interaction between rHSA and FcRn, while the observed decrease...

  13. Fc Gamma Receptor 3B (FCGR3Bc.233C>A-rs5030738) Polymorphism Modifies the Protective Effect of Malaria Specific Antibodies in Ghanaian Children

    DEFF Research Database (Denmark)

    Adu, Bright; Jepsen, Micha Phill Grønholm; Gerds, Thomas A

    2014-01-01

    Immunoglobulin G (IgG) cross-linking with Fc gamma receptor IIIB (FcγRIIIB) triggers neutrophil degranulation, releasing reactive oxygen species with high levels associated with protection against malaria. The FCGR3B-c.233C>A polymorphism thought to influence the interaction between IgG and Fcγ...

  14. Natural IgG autoantibodies are abundant and ubiquitous in human sera, and their number is influenced by age, gender, and disease.

    Directory of Open Access Journals (Sweden)

    Eric P Nagele

    Full Text Available The presence of self-reactive IgG autoantibodies in human sera is largely thought to represent a breakdown in central tolerance and is typically regarded as a harbinger of autoimmune pathology. In the present study, immune-response profiling of human serum from 166 individuals via human protein microarrays demonstrates that IgG autoantibodies are abundant in all human serum, usually numbering in the thousands. These IgG autoantibodies bind to human antigens from organs and tissues all over the body and their serum diversity is strongly influenced by age, gender, and the presence of specific diseases. We also found that serum IgG autoantibody profiles are unique to an individual and remarkably stable over time. Similar profiles exist in rat and swine, suggesting conservation of this immunological feature among mammals. The number, diversity, and apparent evolutionary conservation of autoantibody profiles suggest that IgG autoantibodies have some important, as yet unrecognized, physiological function. We propose that IgG autoantibodies have evolved as an adaptive mechanism for debris-clearance, a function consistent with their apparent utility as diagnostic indicators of disease as already established for Alzheimer's and Parkinson's diseases.

  15. Structural basis for pH-insensitive inhibition of immunoglobulin G recycling by an anti-neonatal Fc receptor antibody

    Energy Technology Data Exchange (ETDEWEB)

    Kenniston, Jon A.; Taylor, Brandy M.; Conley, Gregory P.; Cosic, Janja; Kopacz, Kris J.; Lindberg, Allison P.; Comeau, Stephen R.; Atkins, Kateri; Bullen, Jameson; TenHoor, Christopher; Adelman, Burt A.; Sexton, Daniel J.; Edwards, Thomas E.; Nixon, Andrew E. (Beryllium); (Dyax)

    2017-09-06

    The neonatal Fc receptor FcRn plays a critical role in the trafficking of IgGs across tissue barriers and in retaining high circulating concentrations of both IgG and albumin. Although generally beneficial from an immunological perspective in maintaining IgG populations, FcRn can contribute to the pathogenesis of autoimmune disorders when an abnormal immune response targets normal biological components. We previously described a monoclonal antibody (DX-2507) that binds to FcRn with high affinity at both neutral and acidic pH, prevents the simultaneous binding of IgG, and reduces circulating IgG levels in preclinical animal models. Here, we report a 2.5 Å resolution X-ray crystal structure of an FcRn–DX-2507 Fab complex, revealing a nearly complete overlap of the IgG–Fc binding site in FcRn by complementarity-determining regions in DX-2507. This overlap explains how DX-2507 blocks IgG binding to FcRn and thereby shortens IgG half-life by preventing IgGs from recycling back into circulation. Moreover, the complex structure explains how the DX-2507 interaction is pH-insensitive unlike normal Fc interactions and how serum albumin levels are unaffected by DX-2507 binding. These structural studies could inform antibody-based therapeutic approaches for limiting the effects of IgG-mediated autoimmune disease.

  16. Lin- CD34hi CD117int/hi FcεRI+ cells in human blood constitute a rare population of mast cell progenitors.

    Science.gov (United States)

    Dahlin, Joakim S; Malinovschi, Andrei; Öhrvik, Helena; Sandelin, Martin; Janson, Christer; Alving, Kjell; Hallgren, Jenny

    2016-01-28

    Mast cells are rare tissue-resident immune cells that are involved in allergic reactions, and their numbers are increased in the lungs of asthmatics. Murine lung mast cells arise from committed bone marrow-derived progenitors that enter the blood circulation, migrate through the pulmonary endothelium, and mature in the tissue. In humans, mast cells can be cultured from multipotent CD34(+) progenitor cells. However, a population of distinct precursor cells that give rise to mast cells has remained undiscovered. To our knowledge, this is the first report of human lineage-negative (Lin(-)) CD34(hi) CD117(int/hi) FcεRI(+) progenitor cells, which represented only 0.0053% of the isolated blood cells in healthy individuals. These cells expressed integrin β7 and developed a mast cell-like phenotype, although with a slow cell division capacity in vitro. Isolated Lin(-) CD34(hi) CD117(int/hi) FcεRI(+) blood cells had an immature mast cell-like appearance and expressed high levels of many mast cell-related genes as compared with human blood basophils in whole-transcriptome microarray analyses. Furthermore, serglycin, tryptase, and carboxypeptidase A messenger RNA transcripts were detected by quantitative reverse transcription-polymerase chain reaction. Altogether, we propose that the Lin(-) CD34(hi) CD117(int/hi) FcεRI(+) blood cells are closely related to human tissue mast cells and likely constitute an immediate precursor population, which can give rise to predominantly mast cells. Furthermore, asthmatics with reduced lung function had a higher frequency of Lin(-) CD34(hi) CD117(int/hi) FcεRI(+) blood mast cell progenitors than asthmatics with normal lung function. © 2016 by The American Society of Hematology.

  17. The etiology of multiple sclerosis: genetic evidence for the involvement of the human endogenous retrovirus HERV-Fc1

    DEFF Research Database (Denmark)

    Nexø, Bjørn Andersen; Christensen, Tove; Frederiksen, Jette

    2011-01-01

    or almost-intact genes. We found that SNPs in the gene TRIM5 were inversely correlated with disease. Conversely, SNPs around one retroviral locus, HERV-Fc1, showed a highly significant association with disease. The latter association was limited to a narrow region that contains no other known genes. We...... conclude that HERV-Fc1 and TRIM5 play a role in the etiology of multiple sclerosis. If these results are confirmed, they point to new modes of treatment for multiple sclerosis....

  18. An engineered diatom acting like a plasma cell secreting human IgG antibodies with high efficiency

    Directory of Open Access Journals (Sweden)

    Hempel Franziska

    2012-09-01

    Full Text Available Abstract Background Although there are many different expression systems for recombinant production of pharmaceutical proteins, many of these suffer from drawbacks such as yield, cost, complexity of purification, and possible contamination with human pathogens. Microalgae have enormous potential for diverse biotechnological applications and currently attract much attention in the biofuel sector. Still underestimated, though, is the idea of using microalgae as solar-fueled expression system for the production of recombinant proteins. Results In this study, we show for the first time that completely assembled and functional human IgG antibodies can not only be expressed to high levels in algal systems, but also secreted very efficiently into the culture medium. We engineered the diatom Phaeodactylum tricornutum to synthesize and secrete a human IgG antibody against the Hepatitis B Virus surface protein. As the diatom P. tricornutum is not known to naturally secrete many endogenous proteins, the secreted antibodies are already very pure making extensive purification steps redundant and production extremely cost efficient. Conclusions Microalgae combine rapid growth rates with all the advantages of eukaryotic expression systems, and offer great potential for solar-powered, low cost production of pharmaceutical proteins.

  19. Interactions of phagocytes with the Lyme disease spirochete: role of the Fc receptor

    International Nuclear Information System (INIS)

    Benach, J.L.; Fleit, H.B.; Habicht, G.S.; Coleman, J.L.; Bosler, E.M.; Lane, B.P.

    1984-01-01

    The phagocytic capacity of murine and human mononuclear and polymorphonuclear phagocytes (including peripheral blood monocytes and neutrophils), rabbit and murine peritoneal exudate cells, and the murine macrophage cell line P388D1 against the Lyme disease spirochete was studied. All of these cells were capable of phagocytosing the spirochete; phagocytosis was measured by the uptake of radiolabeled spirochetes, the appearance of immunofluorescent bodies in phagocytic cells, and electron microscopy. Both opsonized and nonopsonized organisms were phagocytosed. The uptake of opsonized organisms by neutrophils was blocked by a monoclonal antibody specific for the Fc receptor and by immune complexes; these findings suggested that most phagocytosis is mediated by the Fc receptor. Similarly, the uptake of opsonized organisms by human monocytes was inhibited by human monomeric IgG1 and by immune complexes. These results illustrate the role of immune phagocytosis of spirochetes in host defense against Lyme disease

  20. Fcγ receptor I alpha chain (CD64) expression in macrophages is critical for the onset of meningitis by Escherichia coli K1.

    Science.gov (United States)

    Mittal, Rahul; Sukumaran, Sunil K; Selvaraj, Suresh K; Wooster, David G; Babu, M Madan; Schreiber, Alan D; Verbeek, J Sjef; Prasadarao, Nemani V

    2010-11-18

    Neonatal meningitis due to Escherichia coli K1 is a serious illness with unchanged morbidity and mortality rates for the last few decades. The lack of a comprehensive understanding of the mechanisms involved in the development of meningitis contributes to this poor outcome. Here, we demonstrate that depletion of macrophages in newborn mice renders the animals resistant to E. coli K1 induced meningitis. The entry of E. coli K1 into macrophages requires the interaction of outer membrane protein A (OmpA) of E. coli K1 with the alpha chain of Fcγ receptor I (FcγRIa, CD64) for which IgG opsonization is not necessary. Overexpression of full-length but not C-terminal truncated FcγRIa in COS-1 cells permits E. coli K1 to enter the cells. Moreover, OmpA binding to FcγRIa prevents the recruitment of the γ-chain and induces a different pattern of tyrosine phosphorylation of macrophage proteins compared to IgG2a induced phosphorylation. Of note, FcγRIa(-/-) mice are resistant to E. coli infection due to accelerated clearance of bacteria from circulation, which in turn was the result of increased expression of CR3 on macrophages. Reintroduction of human FcγRIa in mouse FcγRIa(-/-) macrophages in vitro increased bacterial survival by suppressing the expression of CR3. Adoptive transfer of wild type macrophages into FcγRIa(-/-) mice restored susceptibility to E. coli infection. Together, these results show that the interaction of FcγRI alpha chain with OmpA plays a key role in the development of neonatal meningitis by E. coli K1.

  1. 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 FcγRs.

    Science.gov (United States)

    Valenzuela, Nicole M; Mulder, Arend; Reed, Elaine F

    2013-06-15

    Ab-mediated rejection (AMR) of solid organ transplants is characterized by intragraft macrophages. It is incompletely understood how donor-specific Ab binding to graft endothelium promotes monocyte adhesion, and what, if any, contribution is made by the Fc region of the Ab. We investigated the mechanisms underlying monocyte recruitment by HLA class I (HLA I) Ab-activated endothelium. We used a panel of murine mAbs 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 (m)IgG1 and mIgG2a induced endothelial P-selectin, which was required for monocyte adhesion to endothelium irrespective of subclass. mIgG2a 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 AMR. We confirmed these observations using human HLA allele-specific mAbs and IgG purified from transplant patient sera. HLA I Abs universally elicit endothelial exocytosis leading to monocyte adherence, implying that P-selectin is a putative therapeutic target to prevent macrophage infiltration during AMR. Importantly, the subclass of donor-specific Ab may influence its pathogenesis. These results imply that human IgG1 and human IgG3 should have a greater capacity to trigger monocyte infiltration into the graft than IgG2 or IgG4 due to enhancement by FcγR interactions.

  2. [PHEMA/PEI]–Cu(II) based immobilized metal affinity chromatography cryogels: Application on the separation of IgG from human plasma

    Energy Technology Data Exchange (ETDEWEB)

    Bakhshpour, Monireh; Derazshamshir, Ali; Bereli, Nilay [Department of Chemistry, Biochemistry Division, Hacettepe University, Ankara (Turkey); Elkak, Assem [Laboratory of “Valorisation des Ressources Naturelles et Produits de Santé (VRNPS)”, Doctoral School of Sciences and Technology, Lebanese University, Rafic Hariri University Campus, Hadath (Lebanon); Denizli, Adil, E-mail: denizli@hacettepe.edu [Department of Chemistry, Biochemistry Division, Hacettepe University, Ankara (Turkey)

    2016-04-01

    The immobilized metal-affinity chromatography (IMAC) has gained significant interest as a widespread separation and purification tool for therapeutic proteins, nucleic acids and other biological molecules. The enormous potential of IMAC for proteins with natural surface exposed-histidine residues and for recombinant proteins with histidine clusters. Cryogels as monolithic materials have recently been proposed as promising chromatographic adsorbents for the separation of biomolecules in downstream processing. In the present study, IMAC cryogels have been synthesized and utilized for the adsorption and separation of immunoglobulin G (IgG) from IgG solution and whole human plasma. For this purpose, Cu(II)-ions were coupled to poly(hydroxyethyl methacrylate) PHEMA using poly(ethylene imine) (PEI) as the chelating ligand. In this study the cryogels formation optimized by the varied proportion of PEI from 1% to 15% along with different amounts of Cu (II) as chelating metal. The prepared cryogels were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The [PHEMA/PEI]–Cu(II) cryogels were assayed for their capability to bind the human IgG from aqueous solutions. The IMAC cryogels were found to have high affinity toward human IgG. The adsorption of human IgG was investigated onto the PHEMA/PEI cryogels with (10% PEI) and the concentration of Cu (II) varied as 10, 50, 100 and 150 mg/L. The separation of human IgG was achieved in one purification step at pH 7.4. The maximum adsorption capacity was observed at the [PHEMA/PEI]–Cu(II) (10% PEI) with 72.28 mg/g of human IgG. The purification efficiency and human IgG purity were investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). - Highlights: • Cu(II)-ions were coupled to PHEMA using PEI as the chelating ligand. • Cu(II) chelated [PHEMA/PEI] cryogels for IgG separation were produced. • Maximum IgG adsorption capacity

  3. [PHEMA/PEI]–Cu(II) based immobilized metal affinity chromatography cryogels: Application on the separation of IgG from human plasma

    International Nuclear Information System (INIS)

    Bakhshpour, Monireh; Derazshamshir, Ali; Bereli, Nilay; Elkak, Assem; Denizli, Adil

    2016-01-01

    The immobilized metal-affinity chromatography (IMAC) has gained significant interest as a widespread separation and purification tool for therapeutic proteins, nucleic acids and other biological molecules. The enormous potential of IMAC for proteins with natural surface exposed-histidine residues and for recombinant proteins with histidine clusters. Cryogels as monolithic materials have recently been proposed as promising chromatographic adsorbents for the separation of biomolecules in downstream processing. In the present study, IMAC cryogels have been synthesized and utilized for the adsorption and separation of immunoglobulin G (IgG) from IgG solution and whole human plasma. For this purpose, Cu(II)-ions were coupled to poly(hydroxyethyl methacrylate) PHEMA using poly(ethylene imine) (PEI) as the chelating ligand. In this study the cryogels formation optimized by the varied proportion of PEI from 1% to 15% along with different amounts of Cu (II) as chelating metal. The prepared cryogels were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The [PHEMA/PEI]–Cu(II) cryogels were assayed for their capability to bind the human IgG from aqueous solutions. The IMAC cryogels were found to have high affinity toward human IgG. The adsorption of human IgG was investigated onto the PHEMA/PEI cryogels with (10% PEI) and the concentration of Cu (II) varied as 10, 50, 100 and 150 mg/L. The separation of human IgG was achieved in one purification step at pH 7.4. The maximum adsorption capacity was observed at the [PHEMA/PEI]–Cu(II) (10% PEI) with 72.28 mg/g of human IgG. The purification efficiency and human IgG purity were investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). - Highlights: • Cu(II)-ions were coupled to PHEMA using PEI as the chelating ligand. • Cu(II) chelated [PHEMA/PEI] cryogels for IgG separation were produced. • Maximum IgG adsorption capacity

  4. Rapid desensitization of mice with anti-FcγRIIb/FcγRIII mAb safely prevents IgG-mediated anaphylaxis.

    Science.gov (United States)

    Khodoun, Marat V; Kucuk, Zeynep Yesim; Strait, Richard T; Krishnamurthy, Durga; Janek, Kevin; Clay, Corey D; Morris, Suzanne C; Finkelman, Fred D

    2013-12-01

    Stimulatory IgG receptors (FcγRs) on bone marrow-derived cells contribute to the pathogenesis of several autoimmune and inflammatory disorders. Monoclonal antibodies that block FcγRs might suppress these diseases, but they can induce anaphylaxis. We wanted to determine whether a rapid desensitization approach can safely suppress IgG/FcγR-mediated anaphylaxis. Mice were injected with serially increasing doses of 2.4G2, a rat mAb that blocks the inhibitory FcγR, FcγRIIb, and the stimulatory receptor, FcγRIII. Rectal temperature was used to detect the development of anaphylaxis. Passive and active IgG-mediated anaphylaxis were evaluated in mice that had been rapidly desensitized with 2.4G2 or mock-desensitized in mice in which monocyte/macrophages, basophils, or neutrophils had been depleted or desensitized and in mice in which FcγRI, FcγRIII, and/or FcγRIV had been deleted or blocked. Rapid desensitization with 2.4G2 prevented 2.4G2-induced shock and completely suppressed IgG-mediated anaphylaxis. Rapid desensitization of ovalbumin-sensitized mice with 2.4G2 was safer and more effective than rapid desensitization with ovalbumin. 2.4G2 treatment completely blocked FcγRIII and removed most FcγRI and FcγRIV from nucleated peripheral blood cells. Because IgG(2a)-mediated anaphylaxis was partially FcγRI and FcγRIV dependent, the effects of 2.4G2 on FcγRI and FcγRIV were probably crucial for its complete inhibition of IgG(2a)-mediated anaphylaxis. IgG(2a)-mediated anaphylaxis was partially inhibited by depletion or desensitization of monocyte/macrophages, basophils, or neutrophils. IgG-mediated anaphylaxis can be induced by ligation of FcγRI, FcγRIII, or FcγRIV on monocycte/macrophages, basophils, or neutrophils and can be safely suppressed by rapid desensitization with anti-FcγRII/RIII mAb. A similar approach may safely suppress other FcγR-dependent immunopathology. Published by Mosby, Inc.

  5. Human IgG1 Responses to Surface Localised Schistosoma mansoni Ly6 Family Members Drop following Praziquantel Treatment.

    Directory of Open Access Journals (Sweden)

    Iain W Chalmers

    Full Text Available The heptalaminate-covered, syncytial tegument is an important anatomical adaptation that enables schistosome parasites to maintain long-term, intravascular residence in definitive hosts. Investigation of the proteins present in this surface layer and the immune responses elicited by them during infection is crucial to our understanding of host/parasite interactions. Recent studies have revealed a number of novel tegumental surface proteins including three (SmCD59a, SmCD59b and Sm29 containing uPAR/Ly6 domains (renamed SmLy6A SmLy6B and SmLy6D in this study. While vaccination with SmLy6A (SmCD59a and SmLy6D (Sm29 induces protective immunity in experimental models, human immunoglobulin responses to representative SmLy6 family members have yet to be thoroughly explored.Using a PSI-BLAST-based search, we present a comprehensive reanalysis of the Schistosoma mansoni Ly6 family (SmLy6A-K. Our examination extends the number of members to eleven (including three novel proteins and provides strong evidence that the previously identified vaccine candidate Sm29 (renamed SmLy6D is a unique double uPAR/Ly6 domain-containing representative. Presence of canonical cysteine residues, signal peptides and GPI-anchor sites strongly suggest that all SmLy6 proteins are cell surface-bound. To provide evidence that SmLy6 members are immunogenic in human populations, we report IgG1 (as well as IgG4 and IgE responses against two surface-bound representatives (SmLy6A and SmLy6B within a cohort of S. mansoni-infected Ugandan males before and after praziquantel treatment. While pre-treatment IgG1 prevalence for SmLy6A and SmLy6B differs amongst the studied population (7.4% and 25.3% of the cohort, respectively, these values are both higher than IgG1 prevalence (2.7% for a sub-surface tegumental antigen, SmTAL1. Further, post-treatment IgG1 levels against surface-associated SmLy6A and SmLy6B significantly drop (p = 0.020 and p < 0.001, respectively when compared to rising IgG

  6. Goat anti-rabbit IgG conjugated fluorescent dye-doped silica nanoparticles for human breast carcinoma cell recognition.

    Science.gov (United States)

    Chen, Min-Yan; Chen, Ze-Zhong; Wu, Ling-Ling; Tang, Hong-Wu; Pang, Dai-Wen

    2013-11-12

    We report an indirect method for cancer cell recognition using photostable fluorescent silica nanoprobes as biological labels. The dye-doped fluorescent silica nanoparticles were synthesized using the water-in-oil (W/O) reverse microemulsion method. The silica matrix was produced by the controlled hydrolysis of tetraethylorthosilicate (TEOS) in water nanodroplets with the initiation of ammonia (NH3·H2O). Fluorescein isothiocyanate (FITC) or rhodamine B isothiocyanate conjugated with dextran (RBITC-Dextran) was doped in silica nanoparticles (NPs) with a size of 60 ± 5 nm as a fluorescent signal element by covalent bonding and steric hindrance, respectively. The secondary antibody, goat anti-rabbit IgG, was conjugated on the surface of the PEG-terminated modified FITC-doped or RBITC-Dextran-doped silica nanoparticles (PFSiNPs or PBSiNPs) by covalent binding to the PEG linkers using the cyanogen bromide method. The concentrations of goat anti-rabbit IgG covering the nanoprobes were quantified via the Bradford method. In the proof-of-concept experiment, an epithelial cell adhesion molecule (EpCAM) on the human breast cancer SK-Br-3 cell surface was used as the tumor marker, and the nanoparticle functionalized with rabbit anti-EpCAM antibody was employed as the nanoprobe for cancer cell recognition. Compared with fluorescent dye labeled IgG (FITC-IgG and RBITC-IgG), the designed nanoprobes display dramatically increased stability of fluorescence as well as photostability under continuous irradiation.

  7. Serum IgE and IgG4 against muscle larva excretory-secretory products during the early and late phases of human trichinellosis.

    Science.gov (United States)

    Calcagno, Marcela A; Forastiero, María A; Saracino, María P; Vila, Cecilia C; Venturiello, Stella M

    2017-11-01

    In human trichinellosis, the relevance of the presence and persistence of specific serum IgE and IgG4 during the early and late phases of infection is still controversial.The aim of this work was to determine the percentage of human sera presenting IgE and IgG4 against Trichinella spiralis muscle larvae excretory-secretory products as well as their levels during the early and late phases of the infection. The antigen recognition pattern by serum total immunoglobulins (IgGAM), IgE, and IgG4 was assessed over time. Serum samples during early and late phases were analyzed by ELISA and immunoelectrotransfer blot (IETB).Results showed that (a)-IgE and IgG4 are present at constant levels in both phases; (b)-IgE recognized the glycoproteins of ~ 45 and ~ 55 kDa and IgG4 only the ~ 45 kDa; (c)-in the late phase, the percentage of specific IgE positive sera was higher than that of specific IgG4 by IETB; while in serum samples taken during the early phase, no differences were found between both isotypes; (d)-both isotypes displayed different glycoprotein recognition patterns: the pattern corresponding to IgE was coincident with that of IgGAM, comprising seven glycoproteins (ranging from ~ 116 to ~ 29 kDa), whereas IgG4 revealed four glycoproteins (ranging from ~ 97 to ~ 45 kDa), showing a different sera recognition percentage depending on the phase studied.In conclusion, IgE and IgG4 cannot be considered exclusive isotypes of neither the early nor the late phase of infection and they are as useful as the detection of total antibodies in the early diagnosis.

  8. Expression of human FcgammaRIIIa as a GPI-linked molecule on CHO cells to enable measurement of human IgG binding.

    Science.gov (United States)

    Armour, Kathryn L; Smith, Cheryl S; Clark, Michael R

    2010-03-31

    The efficacy of a therapeutic IgG molecule may be as dependent on the optimisation of the constant region to suit its intended indication as on the selection of its variable regions. A crucial effector function to be maximised or minimised is antibody-dependent cell-mediated cytotoxicity by natural killer cells. Traditional assays of ADCC activity suffer from considerable inter-donor and intra-donor variability, which makes the measurement of antibody binding to human FcgammaRIIIa, the key receptor for ADCC, an attractive alternative method of assessment. Here, we describe the development of cell lines and assays for this purpose. The transmembrane receptor, FcgammaRIIIa, requires co-expression with signal transducing subunits to prevent its degradation, unlike the homologous receptor FcgammaRIIIb that is expressed as a GPI-anchored molecule. Therefore, to simplify the production of cell lines as reliable assay components, we expressed FcgammaRIIIa as a GPI-anchored molecule. Separate, stable CHO cell lines that express either the 158F or the higher-affinity 158V allotype of FcgammaRIIIa were isolated using fluorescence-activated cell sorting. The identities of the expressed receptors were confirmed using a panel of monoclonal antibodies that distinguish between subclasses and allotypes of FcgammaRIII and the cell lines were shown to have slightly higher levels of receptor than FcgammaRIII-positive peripheral blood mononuclear cells. Because the affinity of FcgammaRIIIa for IgG is intermediate amongst the receptors that bind IgG, we were able to use these cell lines to develop flow cytometric assays to measure the binding of both complexed and monomeric immunoglobulin. Thus, by choosing the appropriate method, weakly- or strongly-binding IgG can be efficiently compared. We have quantified the difference in the binding of wildtype IgG1 and IgG3 molecules to the two functional allotypes of the receptor and report that the FcgammaRIIIa-158V-antibody interaction is 3

  9. Expression of HERV-Fc1, a human endogenous retrovirus, is increased in patients with active Multiple Sclerosis

    DEFF Research Database (Denmark)

    Laska, Magdalena Janina; Brudek, Tomasz; Nissen, Kari Konstantin

    2012-01-01

    of a capsid (Gag) protein of HERV-H/F origin by flow cytometry in peripheral blood mononuclear cells (PBMCs) from healthy controls and from MS patients with nonactive or active disease. There was a significant increase in HERV-H/F Gag expression in CD4(+) (P ...-fold increase in extracellular HERV-Fc1 RNA titers in patients with active MS compared with healthy controls (P

  10. 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

  11. Late Development of FcεRγneg Adaptive Natural Killer Cells Upon Human Cytomegalovirus Reactivation in Umbilical Cord Blood Transplantation Recipients

    Directory of Open Access Journals (Sweden)

    Letizia Muccio

    2018-05-01

    Full Text Available In human natural killer (NK cells, human cytomegalovirus (HCMV has been shown to be a driving force capable of inducing the expansion of a highly differentiated NKG2C+CD57+ subset, persisting over time in both HCMV+ healthy subjects and umbilical cord blood transplantation (UCBT recipients experiencing HCMV viral reactivation. In HCMV+ healthy subjects, such expanded NK-cells are characterized by epigenetic modifications that modulate their phenotypic and functional characteristics. In particular, an enhanced ADCC activity is detectable in NK cells lacking the signaling protein FcεRγ. Timing and mechanisms involved in the acquisition of HCMV-induced, adaptive-like features by NK cells are currently unknown. In this study, we investigated the de novo acquisition of several adaptive features in NK cells developing after UCBT by monitoring NK-cell differentiation for at least 2 years after transplant. In UCBT recipients experiencing HCMV reactivation, a rapid phenotypic reconfiguration occurred resulting in the expected expansion of CD56dim NKG2C+CD57+ NK cells. However, while certain HCMV-driven adaptive hallmarks, including high KIR, LILRB1, CD2 and low/negative NKG2A, Siglec-7, and CD161 expression, were acquired early after UCBT (namely by month 6, downregulation of the signaling protein FcεRγ was detected at a later time interval (i.e., by month 12. This feature characterized only a minor fraction of the HCMV-imprinted NKG2C+CD57+ CD56dim NK cell subset, while it was detectable in higher proportions of CD57+ NK cells lacking NKG2C. Interestingly, in patients developing a hyporesponsive CD56−CD16bright NK-cell subset, FcεRγ downregulation occurred in these cells earlier than in CD56dim NK cells. Our data suggest that the acquisition of a fully “adaptive” profile requires signals that may lack in UCBT recipients and/or longer time is needed to obtain a stable epigenetic reprogramming. On the other hand, we found that both HCMV

  12. Subthreshold Desensitization of Human Basophils Re-capitulates the Loss of syk and FcεRI expression Characterized by Other Methods of Desensitization

    Science.gov (United States)

    MacGlashan, Donald

    2012-01-01

    Background Clinical desensitization of patients to drugs involves progressive exposure to escalating doses of drug over a period of 24 hours. In prior studies, this method was recapitulated in vitro to also demonstrate loss of mast cell or basophil responsiveness. However, most signaling studies of human basophils have identified changes in signaling by using other methods of inducing cellular desensitization. Objective This study examined two well-described endpoints of basophil desensitization, loss of syk or FcεRI expression, under conditions of subthreshold desensitization. Methods The loss of FceRI and syk was examined in human basophils. Results It was shown that both loss of syk and FcεRI/IgE occurred during an escalating series of stimulation (anti-IgE Ab) and that expression loss occurred despite the presence of little histamine release. If basophils were first cultured for 3 days in 10 ng/ml IL-3, the concentration-dependence of histamine release shifted to 100 fold lower concentrations of stimulus. However, loss of syk did not show any change in its EC50 while loss of FcεRI also shifted 100 fold. From the perspective of early signal element activation, the marked shift in the EC50 for histamine release was not accompanied by similar shifts in the EC50s for several signaling elements. The EC50s for phospho-Src, phospho-SHIP1, phospho-Syk, or phospho-Cbl did not change while the EC50s for phospho-Erk and the cytosolic calcium response did shift 100 fold. Conclusions These studies show that under normal conditions, subthreshold desensitization leads to loss of two critical signaling molecules (FcεRI and syk) but under at least one condition, treatment with IL-3, it is possible to markedly blunt the loss of syk, but not FcεRI, while executing a proper subthreshold titration. These data also suggest that IL-3 modifies only the sensitivity of signaling elements that are downstream of syk activation. PMID:22702505

  13. The quantitation of parasite-specific human IgG and IgE in sera: evaluation of solid-phase RIA and ELISA methodology

    International Nuclear Information System (INIS)

    Hamilton, R.G.; Adkinson, N.F. Jr.

    1981-01-01

    The authors have developed a non-competitive solid-phase radioimmunoassay (SPRIA) to quantitate both human IgE and IgG antibodies against soluble adult antigens of Brugia malayi (B.m.), a filarial parasite causing extensive infection throughout the tropics. Previously enzyme-linked immunosorbent assays (ELISA) had been used to detect μg/ml levels of IgG anti-B.m., but IgE antibodies were difficult to detect in this system. Since the SPRIA successfully quantitates both IgG and IgE anti-B.m., they sought to examine the reasons for the SPRIA's apparent superiority in detecting IgE anti-B.m. by extracting specific IgG from sera with high levels of IgE and IgG anti-B.m. antibodies. IgE anti-B.m. was then quantitated in these sera using both the SPRIA and ELISA methods. Results indicate that IgG anti-B.m. does not interfere with detection of specific IgE antibody in the SPRIA but does interfere in the ELISA. While ELISA permits detection of IgE anti-B.m. in the absence of competing IgG anti-B.m., as levels of specific IgG increase, the IgE is no longer detectable. These differences between SPRIA and ELISA can be explained by the SPRIA's antigen excess conditions which assure that there are sufficient antigens both to detect all anti-B.m. antibodies present in the serum and to adequately represent all antigen specificities in the crude B.m. extract. Their findings commend the use of SPRIA methods over ELISA in assessment of B.m.-specific IgE antibody in filariasis and indicate a potential role for SPRIA methods in absolute quantitation of specific serum antibodies. (Auth.)

  14. Quantitation of parasite-specific human IgG and IgE in sera: evaluation of solid-phase RIA and ELISA methodology

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, R G [Johns Hopkins Univ., Baltimore, MD (USA). Dept. of Medicine; Hussain, R; Ottesen, E A [National Inst. of Allergy and Infectious Diseases, Bethesda, MD (USA); Adkinson, Jr, N F [Johns Hopkins Univ., Baltimore, MD (USA). School of Medicine

    1981-07-17

    The authors have developed a non-competitive solid-phase radioimmunoassay (SPRIA) to quantitate both human IgE and IgG antibodies against soluble adult antigens of Brugia malayi (B.m.), a filarial parasite causing extensive infection throughout the tropics. Previously enzyme-linked immunosorbent assays (ELISA) had been used to detect ..mu..g/ml levels of IgG anti-B.m., but IgE antibodies were difficult to detect in this system. Since the SPRIA successfully quantitates both IgG and IgE anti-B.m., they sought to examine the reasons for the SPRIA's apparent superiority in detecting IgE anti-B.m. by extracting specific IgG from sera with high levels of IgE and IgG anti-B.m. antibodies. IgE anti-B.m. was then quantitated in these sera using both the SPRIA and ELISA methods. Results indicate that IgG anti-B.m. does not interfere with detection of specific IgE antibody in the SPRIA but does interfere in the ELISA. While ELISA permits detection of IgE anti-B.m. in the absence of competing IgG anti-B.m., as levels of specific IgG increase, the IgE is no longer detectable. These differences between SPRIA and ELISA can be explained by the SPRIA's antigen excess conditions which assure that there are sufficient antigens both to detect all anti-B.m. antibodies present in the serum and to adequately represent all antigen specificities in the crude B.m. extract. Their findings commend the use of SPRIA methods over ELISA in assessment of B.m.-specific IgE antibody in filariasis and indicate a potential role for SPRIA methods in absolute quantitation of specific serum antibodies.

  15. Antibody glycosylation and its impact on the pharmacokinetics and pharmacodynamics of monoclonal antibodies and Fc-fusion proteins.

    Science.gov (United States)

    Liu, Liming

    2015-06-01

    Understanding the impact of glycosylation and keeping a close control on glycosylation of product candidates are required for both novel and biosimilar monoclonal antibodies (mAbs) and Fc-fusion protein development to ensure proper safety and efficacy profiles. Most therapeutic mAbs are of IgG class and contain a glycosylation site in the Fc region at amino acid position 297 and, in some cases, in the Fab region. For Fc-fusion proteins, glycosylation also frequently occurs in the fusion partners. Depending on the expression host, glycosylation patterns in mAb or Fc-fusions can be significantly different, thus significantly impacting the pharmacokinetics (PK) and pharmacodynamics (PD) of mAbs. Glycans that have a major impact on PK and PD of mAb or Fc-fusion proteins include mannose, sialic acids, fucose (Fuc), and galactose (Gal). Mannosylated glycans can impact the PK of the molecule, leading to reduced exposure and potentially lower efficacy. The level of sialic acid, N-acetylneuraminic acid (NANA), can also have a significant impact on the PK of Fc-fusion molecules. Core Fuc in the glycan structure reduces IgG antibody binding to IgG Fc receptor IIIa relative to IgG lacking Fuc, resulting in decreased antibody-dependent cell-mediated cytotoxicity (ADCC) activities. Glycoengineered Chinese hamster ovary (CHO) expression systems can produce afucosylated mAbs that have increased ADCC activities. Terminal Gal in a mAb is important in the complement-dependent cytotoxicity (CDC) in that lower levels of Gal reduce CDC activity. Glycans can also have impacts on the safety of mAb. mAbs produced in murine myeloma cells such as NS0 and SP2/0 contain glycans such as Galα1-3Galβ1-4N-acetylglucosamine-R and N-glycolylneuraminic acid (NGNA) that are not naturally present in humans and can be immunogenic when used as therapeutics. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  16. IgG-Fc-mediated effector functions: molecular definition of interaction sites for effector ligands and the role of glycosylation.

    Science.gov (United States)

    Jefferis, R; Lund, J; Pound, J D

    1998-06-01

    The Fc region of human IgG expresses interaction sites for many effector ligands. In this review the topographical distributions of ten of these sites are discussed in relation to functional requirement. It is apparent that interaction sites localised to the inter-CH2-CH3 domain region of the Fc allow for functional divalency, whereas sites localised to the hinge proximal region of the CH2 domain are functionally monovalent, with expression of the latter sites being particularly dependent on glycosylation. All x-ray crystal structures for Fc and Fc-ligand complexes report that the protein structure of the hinge proximal region of the CH2 domain is "disordered", suggesting "internal mobility". We propose a model in which such "internal mobility" results in the generation of a dynamic equilibrium between multiple conformers, certain of which express interaction sites specific to individual ligands. The emerging understanding of the influence of oligosaccharide/protein interactions on protein conformation and biological function of IgG antibodies suggests a potential to generate novel glycoforms of antibody molecules having unique profiles of effector functions.

  17. Safety and pharmacokinetics of the Fc-modified HIV-1 human monoclonal antibody VRC01LS: A Phase 1 open-label clinical trial in healthy adults

    OpenAIRE

    Gaudinski, Martin R.; Coates, Emily E.; Houser, Katherine V.; Chen, Grace L.; Yamshchikov, Galina; Saunders, Jamie G.; Holman, LaSonji A.; Gordon, Ingelise; Plummer, Sarah; Hendel, Cynthia S.; Conan-Cibotti, Michelle; Lorenzo, Margarita Gomez; Sitar, Sandra; Carlton, Kevin; Laurencot, Carolyn

    2018-01-01

    Background VRC01 is a human broadly neutralizing monoclonal antibody (bnMAb) against the CD4-binding site of the HIV-1 envelope glycoprotein (Env) that is currently being evaluated in a Phase IIb adult HIV-1 prevention efficacy trial. VRC01LS is a modified version of VRC01, designed for extended serum half-life by increased binding affinity to the neonatal Fc receptor. Methods and findings This Phase I dose-escalation study of VRC01LS in HIV-negative healthy adults was conducted by the Vaccin...

  18. Comprehensive Analysis of the Therapeutic IgG4 Antibody Pembrolizumab: Hinge Modification Blocks Half Molecule Exchange In Vitro and In Vivo.

    Science.gov (United States)

    Yang, Xiaoyu; Wang, Fengqiang; Zhang, Ying; Wang, Larry; Antonenko, Svetlana; Zhang, Shuli; Zhang, Yi Wei; Tabrizifard, Mohammad; Ermakov, Grigori; Wiswell, Derek; Beaumont, Maribel; Liu, Liming; Richardson, Daisy; Shameem, Mohammed; Ambrogelly, Alexandre

    2015-12-01

    IgG4 antibodies are evolving as an important class of cancer immunotherapies. However, human IgG4 can undergo Fab arm (half molecule) exchange with other IgG4 molecules in vivo. The hinge modification by a point mutation (S228P) prevents half molecule exchange of IgG4. However, the experimental confirmation is still expected by regulatory agencies. Here, we report for the first time the extensive analysis of half molecule exchange for a hinge-modified therapeutic IgG4 molecule, pembrolizumab (Keytruda) targeting programmed death 1 (PD1) receptor that was approved for advanced melanoma. Studies were performed in buffer or human serum using multiple exchange partners including natalizumab (Tysabri) and human IgG4 pool. Formation of bispecific antibodies was monitored by fluorescence resonance energy transfer, exchange with Fc fragments, mixed mode chromatography, immunoassays, and liquid chromatography-mass spectrometry. The half molecule exchange was also examined in vivo in SCID (severe combined immunodeficiency) mice. Both in vitro and in vivo results indicate that the hinge modification in pembrolizumab prevented half molecule exchange, whereas the unmodified counterpart anti-PD1 wt showed active exchange activity with other IgG4 antibodies or self-exchange activity with its own molecules. Our work, as an example expected for meeting regulatory requirements, contributes to establish without ambiguity that hinge-modified IgG4 antibodies are suitable for biotherapeutic applications. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  19. 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.

  20. Study of chronic hemolytic anaemia patients in Rio de Janeiro: prevalence of anti-human parvovirus B19 IgG antibodies and the developement aplastic crises

    Directory of Open Access Journals (Sweden)

    SANT'ANNA Anadayr L.M.

    2002-01-01

    Full Text Available The prevalence of anti-human parvovirus B19 IgG antibodies was determined in sera from 165 chronic hemolytic anemia patients, receiving medical care at Instituto Estadual de Hematologia (IEHE, Rio de Janeiro, during the year of 1994. This sample represents around 10% of the chronic hemolytic anemia patients attending at IEHE. Most of these patients (140 have sickle cell disease. Anti-B19 IgG antibodies were detected in 32.1% of patients. No statistically significant difference (p > 0.05 was seen between IgG antibody prevalence in male (27.8% and female (35.5% patients. Anti-B19 IgG antibodies were more frequent in older (37.6% than younger (28.2% than 20 years old patients, although this difference had no statistical significance (p > 0.05. Anti-B19 IgG antibody prevalence showed that 67.9% of patients enrolled in the study were susceptible to B19 acute infection. With the aim to detect acute B19 infection, patients follow up continued until February 1996. During this period four patients presented transient aplastic crisis due to human parvovirus B19 as confirmed by the detection of specific IgM antibodies. All four patients were younger than 20 years old, and 3 were younger than 10 years old. Three of them were sickle cell disease patients. Three of the four acute B19 infection occurred during 1994 springtime.

  1. Activation of human natural killer cells by the soluble form of cellular prion protein

    International Nuclear Information System (INIS)

    Seong, Yeon-Jae; Sung, Pil Soo; Jang, Young-Soon; Choi, Young Joon; Park, Bum-Chan; Park, Su-Hyung; Park, Young Woo; Shin, Eui-Cheol

    2015-01-01

    Cellular prion protein (PrP C ) is widely expressed in various cell types, including cells of the immune system. However, the specific roles of PrP C in the immune system have not been clearly elucidated. In the present study, we investigated the effects of a soluble form of recombinant PrP C protein on human natural killer (NK) cells. Recombinant soluble PrP C protein was generated by fusion of human PrP C with the Fc portion of human IgG 1 (PrP C -Fc). PrP C -Fc binds to the surface of human NK cells, particularly to CD56 dim NK cells. PrP C -Fc induced the production of cytokines and chemokines and the degranulation of granzyme B from NK cells. In addition, PrP C -Fc facilitated the IL-15-induced proliferation of NK cells. PrP C -Fc induced phosphorylation of ERK-1/2 and JNK in NK cells, and inhibitors of the ERK or the JNK pathways abrogated PrP C -Fc-induced cytokine production in NK cells. In conclusion, the soluble form of recombinant PrP C -Fc protein activates human NK cells via the ERK and JNK signaling pathways. - Highlights: • Recombinant soluble PrP C (PrP C -Fc) was generated by fusion of human PrP C with IgG1 Fc portion. • PrP C -Fc protein induces the production of cytokines and degranulation from human NK cells. • PrP C -Fc protein enhances the IL-15-induced proliferation of human NK cells. • PrP C -Fc protein activates human NK cells via the ERK and JNK signaling pathways

  2. An Enhanced Pre- and Postnatal Development Study in Cynomolgus Monkeys with Tabalumab: A Human IgG4 Monoclonal Antibody.

    Science.gov (United States)

    Breslin, William J; Hilbish, Kim G; Martin, Jennifer A; Halstead, Carolyn A; Newcomb, Deanna L; Chellman, Gary J

    2015-06-01

    Tabalumab, a human IgG4 monoclonal antibody (mAb) with neutralizing activity against both soluble and membrane B-cell activating factor (BAFF), has been under development for the treatment of autoimmune diseases. The purpose of this study was to determine the potential adverse effects of maternal tabalumab exposure on pregnancy, parturition, and lactation of the mothers and on the growth, viability, and development of the offspring through postnatal day (PND) 204. Tabalumab was administered by subcutaneous injection to presumed pregnant cynomolgus monkeys (16-19 per group) every 2 weeks from gestation day (GD) 20 to 22 until parturition at doses of 0, 0.3, or 30 mg/kg. Evaluations in mothers and infants included clinical signs, body weight, toxicokinetics, blood lymphocyte phenotyping, T-cell-dependent antibody response (infants only), antitherapeutic antibody (ATA), organ weights (infants only), and gross and microscopic histopathology. Infants were also examined for external and visceral morphologic and neurobehavioral development. There were no adverse tabalumab-related effects on maternal or infant endpoints. An expected pharmacological decrease in peripheral blood B-lymphocytes occurred in adults and infants; however, B-cell recovery was evident by PND154 in adults and infants at 0.3 mg/kg and by PND204 in infants at 30 mg/kg. At 30 mg/kg, a reduced IgM antibody response to T-cell-dependent antigen keyhole limpet hemocyanin (KLH) was observed following primary immunization. Following secondary KLH immunization, all infants in both dose groups mounted anti-KLH IgM and IgG antibody responses similar to control. Placental and mammary transfer of tabalumab was demonstrated. In conclusion, the no-observed-adverse-effect level for maternal and developmental toxicity was 30 mg/kg, the highest dose tested. Exposures at 30 mg/kg provide a margin of safety of 16× the anticipated clinical exposure. © 2015 Wiley Periodicals, Inc.

  3. Immunoglobulin G (IgG) Fab glycosylation analysis using a new mass spectrometric high-throughput profiling method reveals pregnancy-associated changes.

    Science.gov (United States)

    Bondt, Albert; Rombouts, Yoann; Selman, Maurice H J; Hensbergen, Paul J; Reiding, Karli R; Hazes, Johanna M W; Dolhain, Radboud J E M; Wuhrer, Manfred

    2014-11-01

    The N-linked glycosylation of the constant fragment (Fc) of immunoglobulin G has been shown to change during pathological and physiological events and to strongly influence antibody inflammatory properties. In contrast, little is known about Fab-linked N-glycosylation, carried by ∼ 20% of IgG. Here we present a high-throughput workflow to analyze Fab and Fc glycosylation of polyclonal IgG purified from 5 μl of serum. We were able to detect and quantify 37 different N-glycans by means of MALDI-TOF-MS analysis in reflectron positive mode using a novel linkage-specific derivatization of sialic acid. This method was applied to 174 samples of a pregnancy cohort to reveal Fab glycosylation features and their change with pregnancy. Data analysis revealed marked differences between Fab and Fc glycosylation, especially in the levels of galactosylation and sialylation, incidence of bisecting GlcNAc, and presence of high mannose structures, which were all higher in the Fab portion than the Fc, whereas Fc showed higher levels of fucosylation. Additionally, we observed several changes during pregnancy and after delivery. Fab N-glycan sialylation was increased and bisection was decreased relative to postpartum time points, and nearly complete galactosylation of Fab glycans was observed throughout. Fc glycosylation changes were similar to results described before, with increased galactosylation and sialylation and decreased bisection during pregnancy. We expect that the parallel analysis of IgG Fab and Fc, as set up in this paper, will be important for unraveling roles of these glycans in (auto)immunity, which may be mediated via recognition by human lectins or modulation of antigen binding. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. Immunoglobulin G (IgG) Fab Glycosylation Analysis Using a New Mass Spectrometric High-throughput Profiling Method Reveals Pregnancy-associated Changes*

    Science.gov (United States)

    Bondt, Albert; Rombouts, Yoann; Selman, Maurice H. J.; Hensbergen, Paul J.; Reiding, Karli R.; Hazes, Johanna M. W.; Dolhain, Radboud J. E. M.; Wuhrer, Manfred

    2014-01-01

    The N-linked glycosylation of the constant fragment (Fc) of immunoglobulin G has been shown to change during pathological and physiological events and to strongly influence antibody inflammatory properties. In contrast, little is known about Fab-linked N-glycosylation, carried by ∼20% of IgG. Here we present a high-throughput workflow to analyze Fab and Fc glycosylation of polyclonal IgG purified from 5 μl of serum. We were able to detect and quantify 37 different N-glycans by means of MALDI-TOF-MS analysis in reflectron positive mode using a novel linkage-specific derivatization of sialic acid. This method was applied to 174 samples of a pregnancy cohort to reveal Fab glycosylation features and their change with pregnancy. Data analysis revealed marked differences between Fab and Fc glycosylation, especially in the levels of galactosylation and sialylation, incidence of bisecting GlcNAc, and presence of high mannose structures, which were all higher in the Fab portion than the Fc, whereas Fc showed higher levels of fucosylation. Additionally, we observed several changes during pregnancy and after delivery. Fab N-glycan sialylation was increased and bisection was decreased relative to postpartum time points, and nearly complete galactosylation of Fab glycans was observed throughout. Fc glycosylation changes were similar to results described before, with increased galactosylation and sialylation and decreased bisection during pregnancy. We expect that the parallel analysis of IgG Fab and Fc, as set up in this paper, will be important for unraveling roles of these glycans in (auto)immunity, which may be mediated via recognition by human lectins or modulation of antigen binding. PMID:25004930

  5. Isolation of high-affinity human IgE and IgG antibodies recognising Bet v 1 and Humicola lanuginosa lipase from combinatorial phage libraries

    DEFF Research Database (Denmark)

    Jakobsen, Charlotte G; Bødtger, Uffe; Kristensen, Peter

    2004-01-01

    Allergen-specific Fab fragments isolated from combinatorial IgE and IgG libraries are useful tools for studying allergen-antibody interactions. To characterise the interaction between different allergens and antibodies we have created recombinant human phage antibody libraries in the Fab format...

  6. Structural and immunological characterization of hydroxyl radical modified human IgG: Clinical correlation in rheumatoid arthritis

    Science.gov (United States)

    Islam, Sidra; Mir, Abdul Rouf; Arfat, Mir Yasir; Khan, Farzana; Zaman, Masihuz; Ali, Asif; Moinuddin

    2018-04-01

    Structural alterations in proteins under oxidative stress have been widely implicated in the immuno-pathology of various disorders. This study has evaluated the extent of damage in the conformational characteristics of IgG by hydroxyl radical (OHrad) and studied its implications in the immuno-pathology of rheumatoid arthritis (RA). Using various biophysical and biochemical techniques, changes in aromatic microenvironment of the IgG and the protein aggregation became evident after treatment with OHrad . The SDS-PAGE study confirmed the protein aggregation while far ultraviolet circular dichroism spectroscopy (Far-UV CD) and fourier transform infrared spectroscopy (FTIR) inferred towards the alterations in secondary structure of IgG under OHrad stress. Dynamic light scattering showed that the modification increased the hydrodynamic radius and polydispersity of IgG. The free arginine and lysine content reduced upon modification. OHrad induced aggregation was confirmed by enhanced thioflavin-T (ThT) fluorescence and red shift in the congo red (CR) absorbance. The study on experimental animals reiterates the earlier findings of enhanced immunogenicity of OHrad treated IgG (OHrad -IgG) compared to that of native IgG. OHrad -IgG strongly interacted with the antibodies derived from the serum of 80 rheumatoid arthritis (RA) patients. The overwhelming and strong tendency of OHrad -IgG to bind the antibodies derived from the serum of RA patients points towards the modification of IgG under patho-physiological conditions in RA that generate neo-epitopes and eventually cause the generation of auto antibodies that circulate in the patient sera. Further studies on this aspect may possibly lead to the development of a biomarker for RA.

  7. Exploiting light chains for the scalable generation and platform purification of native human bispecific IgG

    Science.gov (United States)

    Fischer, Nicolas; Elson, Greg; Magistrelli, Giovanni; Dheilly, Elie; Fouque, Nicolas; Laurendon, Amélie; Gueneau, Franck; Ravn, Ulla; Depoisier, Jean-François; Moine, Valery; Raimondi, Sylvain; Malinge, Pauline; Di Grazia, Laura; Rousseau, François; Poitevin, Yves; Calloud, Sébastien; Cayatte, Pierre-Alexis; Alcoz, Mathias; Pontini, Guillemette; Fagète, Séverine; Broyer, Lucile; Corbier, Marie; Schrag, Delphine; Didelot, Gérard; Bosson, Nicolas; Costes, Nessie; Cons, Laura; Buatois, Vanessa; Johnson, Zoe; Ferlin, Walter; Masternak, Krzysztof; Kosco-Vilbois, Marie

    2015-01-01

    Bispecific antibodies enable unique therapeutic approaches but it remains a challenge to produce them at the industrial scale, and the modifications introduced to achieve bispecificity often have an impact on stability and risk of immunogenicity. Here we describe a fully human bispecific IgG devoid of any modification, which can be produced at the industrial scale, using a platform process. This format, referred to as a κλ-body, is assembled by co-expressing one heavy chain and two different light chains, one κ and one λ. Using ten different targets, we demonstrate that light chains can play a dominant role in mediating specificity and high affinity. The κλ-bodies support multiple modes of action, and their stability and pharmacokinetic properties are indistinguishable from therapeutic antibodies. Thus, the κλ-body represents a unique, fully human format that exploits light-chain variable domains for antigen binding and light-chain constant domains for robust downstream processing, to realize the potential of bispecific antibodies. PMID:25672245

  8. Ebolavirus Glycoprotein Fc Fusion Protein Protects Guinea Pigs against Lethal Challenge

    Science.gov (United States)

    Konduru, Krishnamurthy; Shurtleff, Amy C.; Bradfute, Steven B.; Nakamura, Siham; Bavari, Sina; Kaplan, Gerardo

    2016-01-01

    Ebola virus (EBOV), a member of the Filoviridae that can cause severe hemorrhagic fever in humans and nonhuman primates, poses a significant threat to the public health. Currently, there are no licensed vaccines or therapeutics to prevent and treat EBOV infection. Several vaccines based on the EBOV glycoprotein (GP) are under development, including vectored, virus-like particles, and protein-based subunit vaccines. We previously demonstrated that a subunit vaccine containing the extracellular domain of the Ebola ebolavirus (EBOV) GP fused to the Fc fragment of human IgG1 (EBOVgp-Fc) protected mice against EBOV lethal challenge. Here, we show that the EBOVgp-Fc vaccine formulated with QS-21, alum, or polyinosinic-polycytidylic acid-poly-L-lysine carboxymethylcellulose (poly-ICLC) adjuvants induced strong humoral immune responses in guinea pigs. The vaccinated animals developed anti-GP total antibody titers of approximately 105−106 and neutralizing antibody titers of approximately 103 as assessed by a BSL-2 neutralization assay based on vesicular stomatitis virus (VSV) pseudotypes. The poly-ICLC formulated EBOVgp-Fc vaccine protected all the guinea pigs against EBOV lethal challenge performed under BSL-4 conditions whereas the same vaccine formulated with QS-21 or alum only induced partial protection. Vaccination with a mucin-deleted EBOVgp-Fc construct formulated with QS-21 adjuvant did not have a significant effect in anti-GP antibody levels and protection against EBOV lethal challenge compared to the full-length GP construct. The bulk of the humoral response induced by the EBOVgp-Fc vaccine was directed against epitopes outside the EBOV mucin region. Our findings indicate that different adjuvants can eliciting varying levels of protection against lethal EBOV challenge in guinea pigs vaccinated with EBOVgp-Fc, and suggest that levels of total anti-GP antibodies elicit by protein-based GP subunit vaccines do not correlate with protection. Our data further support

  9. Ebolavirus Glycoprotein Fc Fusion Protein Protects Guinea Pigs against Lethal Challenge.

    Science.gov (United States)

    Konduru, Krishnamurthy; Shurtleff, Amy C; Bradfute, Steven B; Nakamura, Siham; Bavari, Sina; Kaplan, Gerardo

    2016-01-01

    Ebola virus (EBOV), a member of the Filoviridae that can cause severe hemorrhagic fever in humans and nonhuman primates, poses a significant threat to the public health. Currently, there are no licensed vaccines or therapeutics to prevent and treat EBOV infection. Several vaccines based on the EBOV glycoprotein (GP) are under development, including vectored, virus-like particles, and protein-based subunit vaccines. We previously demonstrated that a subunit vaccine containing the extracellular domain of the Ebola ebolavirus (EBOV) GP fused to the Fc fragment of human IgG1 (EBOVgp-Fc) protected mice against EBOV lethal challenge. Here, we show that the EBOVgp-Fc vaccine formulated with QS-21, alum, or polyinosinic-polycytidylic acid-poly-L-lysine carboxymethylcellulose (poly-ICLC) adjuvants induced strong humoral immune responses in guinea pigs. The vaccinated animals developed anti-GP total antibody titers of approximately 105-106 and neutralizing antibody titers of approximately 103 as assessed by a BSL-2 neutralization assay based on vesicular stomatitis virus (VSV) pseudotypes. The poly-ICLC formulated EBOVgp-Fc vaccine protected all the guinea pigs against EBOV lethal challenge performed under BSL-4 conditions whereas the same vaccine formulated with QS-21 or alum only induced partial protection. Vaccination with a mucin-deleted EBOVgp-Fc construct formulated with QS-21 adjuvant did not have a significant effect in anti-GP antibody levels and protection against EBOV lethal challenge compared to the full-length GP construct. The bulk of the humoral response induced by the EBOVgp-Fc vaccine was directed against epitopes outside the EBOV mucin region. Our findings indicate that different adjuvants can eliciting varying levels of protection against lethal EBOV challenge in guinea pigs vaccinated with EBOVgp-Fc, and suggest that levels of total anti-GP antibodies elicit by protein-based GP subunit vaccines do not correlate with protection. Our data further support

  10. Ebolavirus Glycoprotein Fc Fusion Protein Protects Guinea Pigs against Lethal Challenge.

    Directory of Open Access Journals (Sweden)

    Krishnamurthy Konduru

    Full Text Available Ebola virus (EBOV, a member of the Filoviridae that can cause severe hemorrhagic fever in humans and nonhuman primates, poses a significant threat to the public health. Currently, there are no licensed vaccines or therapeutics to prevent and treat EBOV infection. Several vaccines based on the EBOV glycoprotein (GP are under development, including vectored, virus-like particles, and protein-based subunit vaccines. We previously demonstrated that a subunit vaccine containing the extracellular domain of the Ebola ebolavirus (EBOV GP fused to the Fc fragment of human IgG1 (EBOVgp-Fc protected mice against EBOV lethal challenge. Here, we show that the EBOVgp-Fc vaccine formulated with QS-21, alum, or polyinosinic-polycytidylic acid-poly-L-lysine carboxymethylcellulose (poly-ICLC adjuvants induced strong humoral immune responses in guinea pigs. The vaccinated animals developed anti-GP total antibody titers of approximately 105-106 and neutralizing antibody titers of approximately 103 as assessed by a BSL-2 neutralization assay based on vesicular stomatitis virus (VSV pseudotypes. The poly-ICLC formulated EBOVgp-Fc vaccine protected all the guinea pigs against EBOV lethal challenge performed under BSL-4 conditions whereas the same vaccine formulated with QS-21 or alum only induced partial protection. Vaccination with a mucin-deleted EBOVgp-Fc construct formulated with QS-21 adjuvant did not have a significant effect in anti-GP antibody levels and protection against EBOV lethal challenge compared to the full-length GP construct. The bulk of the humoral response induced by the EBOVgp-Fc vaccine was directed against epitopes outside the EBOV mucin region. Our findings indicate that different adjuvants can eliciting varying levels of protection against lethal EBOV challenge in guinea pigs vaccinated with EBOVgp-Fc, and suggest that levels of total anti-GP antibodies elicit by protein-based GP subunit vaccines do not correlate with protection. Our data

  11. Prophylactic anti-D preparations display variable decreases in Fc-fucosylation of anti-D.

    Science.gov (United States)

    Kapur, Rick; Della Valle, Luciana; Verhagen, Onno J H M; Hipgrave Ederveen, Agnes; Ligthart, Peter; de Haas, Masja; Kumpel, Belinda; Wuhrer, Manfred; van der Schoot, C Ellen; Vidarsson, Gestur

    2015-03-01

    RhIG is obtained from hyperimmunized healthy anti-D donors (HIDs) boosted with D+ red blood cells (RBCs). One hypothesis for its mechanism of action is fast clearance of opsonized D+ RBCs through Fcγ receptor (FcγR)III. Levels of immunoglobulin (Ig)G Fc-fucosylation influence interactions with FcγRIII, with less Fc-fucosylation strengthening the interaction. Anti-D IgG1 Fc-glycosylation patterns in 93 plasma samples from 28 male and 28 female Dutch HIDs and RhIG were analyzed with mass spectrometry. The Fc-glycosylation profiles of HIDs were evaluated with regard to their immunization history. HID sera demonstrated clearly lowered anti-D Fc-fucosylation compared to normal IgG fucosylation (93%); this was more pronounced for female than for male HIDs (47% vs. 65%, p = 0.001). RhIG preparations from seven manufacturers varied greatly in the level of Fc-fucosylation (56%-91%). The level of fucosylation slightly increased upon repeated immunization, although it remained fairly constant over time. The RhIG from the different manufacturers all demonstrated increased Fc-galactosylation (64%-82%) compared to total IgG (38%-51%). RhIG preparations vary in Fc-fucosylation and all demonstrate increased galactosylation. Despite not knowing the exact working mechanism, immunoprophylaxis could perhaps be optimized by selection of donors whose anti-D have low amounts of Fc-fucose, to increase the clearance activity of anti-D preparations, as well as high amounts of galactosylation, for anti-inflammatory effects. Implementing a biologic assay in the standardization of RhIG preparations might be considered. © 2014 AABB.

  12. NOG-hIL-4-Tg, a new humanized mouse model for producing tumor antigen-specific IgG antibody by peptide vaccination.

    Directory of Open Access Journals (Sweden)

    Yoshie Kametani

    Full Text Available Immunodeficient mice transplanted with human peripheral blood mononuclear cells (PBMCs are promising tools to evaluate human immune responses to vaccines. However, these mice usually develop severe graft-versus-host disease (GVHD, which makes estimation of antigen-specific IgG production after antigen immunization difficult. To evaluate antigen-specific IgG responses in PBMC-transplanted immunodeficient mice, we developed a novel NOD/Shi-scid-IL2rγnull (NOG mouse strain that systemically expresses the human IL-4 gene (NOG-hIL-4-Tg. After human PBMC transplantation, GVHD symptoms were significantly suppressed in NOG-hIL-4-Tg compared to conventional NOG mice. In kinetic analyses of human leukocytes, long-term engraftment of human T cells has been observed in peripheral blood of NOG-hIL-4-Tg, followed by dominant CD4+ T rather than CD8+ T cell proliferation. Furthermore, these CD4+ T cells shifted to type 2 helper (Th2 cells, resulting in long-term suppression of GVHD. Most of the human B cells detected in the transplanted mice had a plasmablast phenotype. Vaccination with HER2 multiple antigen peptide (CH401MAP or keyhole limpet hemocyanin (KLH successfully induced antigen-specific IgG production in PBMC-transplanted NOG-hIL-4-Tg. The HLA haplotype of donor PBMCs might not be relevant to the antibody secretion ability after immunization. These results suggest that the human PBMC-transplanted NOG-hIL-4-Tg mouse is an effective tool to evaluate the production of antigen-specific IgG antibodies.

  13. 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.

  14. 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

  15. Preparación de un conjugado peroxidasa-anti IgG humana (cadena en conejo Preparation of a peroxidase-anti human IgG conjugate (chain g in rabbit

    Directory of Open Access Journals (Sweden)

    Julio C Merlín Linares

    2001-08-01

    Full Text Available Se preparó un conjugado con peroxidasa a partir de los anticuerpos específicos aislados de un suero de conejo anti cadenas g de la IgG humana. Los anticuerpos específicos se aislaron por cromatografía de afinidad, y el conjugado se preparó por el método de oxidación con peryodato. El conjugado obtenido presentó una relación molar IgG/peroxidasa de 1,07, un valor de RZ de 0,33 y resultó evaluado satisfactoriamente en cuanto a su especificidad y reactividad en los ensayos inmunoenzimáticos realizadosA peroxidase conjugate was prepared starting from the specific antibodies isolated from an anti-chain rabbit serum and from human IgG. The specific antibodies were isolated by affinity chromatography and the conjugate was prepared by the method of oxidation with periodate. The conjugate obtained presented a molar IgG/peroxidase relation of 1.07, a RZ value of 0.33 and it was satisfactorily evaluated as regards its specificity and reactivity in the immunoenzimatic assays carried out

  16. Fc-fusion technology and recombinant FVIII and FIX in the management of the hemophilias.

    Science.gov (United States)

    Mancuso, Maria Elisa; Mannucci, Pier Mannuccio

    2014-01-01

    Prophylaxis with regular infusions of factor VIII (FVIII)- or factor IX (FIX)- containing products is the mainstay of modern hemophilia care. However, this therapeutic regimen is inconvenient, requiring repeated intravenous injections from childhood. Approaches meant to prolong the half-life of FVIII and FIX in plasma have been developed in order to improve the feasibility and acceptability of replacement therapy, extending protection from bleeding, reducing infusion frequency and hence the need for venous access devices in young children. Several strategies have been implemented to enhance the pharmacokinetics of clotting factors, including conjugation with polyethylene glycol and the production by genetic engineering of fusion proteins containing the coagulation factors linked to a long-lived plasma protein such as albumin or the Fc fragment of immunoglobulin (Ig)G. The latter technology is one of the most promising, since the prolongation of FVIII and FIX half-life is obtained by exploiting the physiological binding of the Fc domain to the neonatal Fc receptor. Fc fusion monomers have been obtained with both recombinant FVIII (rFVIIIFc) and FIX (rFIXFc), and data from preclinical and clinical studies showed improved pharmacokinetics for both factors, which are produced in human embryonic kidney (HEK) 293 cells, thus ensuring full human post-translational modifications. In Phase I/IIa studies, rFVIIIFc and rFIXFc showed 1.5-1.7 fold and 3.0-4.0 fold longer elimination half-life, respectively. Similar data have been obtained in the Phase III clinical studies with rFVIIIFc and rFIX-Fc published recently. Both drugs were satisfactorily safe, particularly with respect to immunogenicity, and no serious adverse event was observed.

  17. Plant-expressed Fc-fusion protein tetravalent dengue vaccine with inherent adjuvant properties.

    Science.gov (United States)

    Kim, Mi Young; Copland, Alastair; Nayak, Kaustuv; Chandele, Anmol; Ahmed, Muhammad S; Zhang, Qibo; Diogo, Gil R; Paul, Matthew J; Hofmann, Sven; Yang, Moon-Sik; Jang, Yong-Suk; Ma, Julian K-C; Reljic, Rajko

    2017-12-09

    Dengue is a major global disease requiring improved treatment and prevention strategies. The recently licensed Sanofi Pasteur Dengvaxia vaccine does not protect children under the age of nine, and additional vaccine strategies are thus needed to halt this expanding global epidemic. Here, we employed a molecular engineering approach and plant expression to produce a humanized and highly immunogenic poly-immunoglobulin G scaffold (PIGS) fused to the consensus dengue envelope protein III domain (cEDIII). The immunogenicity of this IgG Fc receptor-targeted vaccine candidate was demonstrated in transgenic mice expressing human FcγRI/CD64, by induction of neutralizing antibodies and evidence of cell-mediated immunity. Furthermore, these molecules were able to prime immune cells from human adenoid/tonsillar tissue ex vivo as evidenced by antigen-specific CD4 + and CD8 + T-cell proliferation, IFN-γ and antibody production. The purified polymeric fraction of dengue PIGS (D-PIGS) induced stronger immune activation than the monomeric form, suggesting a more efficient interaction with the low-affinity Fcγ receptors on antigen-presenting cells. These results show that the plant-expressed D-PIGS have the potential for translation towards a safe and easily scalable single antigen-based tetravalent dengue vaccine. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  18. Mac-1 (CD11b/CD18) is essential for Fc receptor-mediated neutrophil cytotoxicity and immunologic synapse formation.

    Science.gov (United States)

    van Spriel, A B; Leusen, J H; van Egmond, M; Dijkman, H B; Assmann, K J; Mayadas, T N; van de Winkel, J G

    2001-04-15

    Receptors for human immunoglobulin (Ig)G and IgA initiate potent cytolysis of antibody (Ab)-coated targets by polymorphonuclear leukocytes (PMNs). Mac-1 (complement receptor type 3, CD11b/CD18) has previously been implicated in receptor cooperation with Fc receptors (FcRs). The role of Mac-1 in FcR-mediated lysis of tumor cells was characterized by studying normal human PMNs, Mac-1-deficient mouse PMNs, and mouse PMNs transgenic for human FcR. All PMNs efficiently phagocytosed Ab-coated particles. However, antibody-dependent cellular cytotoxicity (ADCC) was abrogated in Mac-1(-/-) PMNs and in human PMNs blocked with anti-Mac-1 monoclonal Ab (mAb). Mac-1(-/-) PMNs were unable to spread on Ab-opsonized target cells and other Ab-coated surfaces. Confocal laser scanning and electron microscopy revealed a striking difference in immunologic synapse formation between Mac-1(-/-) and wild-type PMNs. Also, respiratory burst activity could be measured outside membrane-enclosed compartments by using Mac-1(-/-) PMNs bound to Ab-coated tumor cells, in contrast to wild-type PMNs. In summary, these data document an absolute requirement of Mac-1 for FcR-mediated PMN cytotoxicity toward tumor targets. Mac-1(-/-) PMNs exhibit defective spreading on Ab-coated targets, impaired formation of immunologic synapses, and absent tumor cytolysis.

  19. High prevalence of human anti-bovine IgG antibodies as the major cause of false positive reactions in two-site immunoassays based on monoclonal antibodies

    DEFF Research Database (Denmark)

    Andersen, Ditte C; Koch, Claus; Jensen, Charlotte H

    2004-01-01

    were purified by protein G affinity chromatography from culture supernatant containing 10% (v/v) fetal calf serum (FCS). Human anti-animal IgG (bovine, mouse, horse, and swine) antibodies and human anti-bovine serum albumin antibodies were measured using an ELISA design, with direct bridging...... of the solid phase and biotinylated antigens. The false positive reactions were abolished by addition of 1% (v/v) bovine serum to the dilution buffer (DB). Human anti-bovine IgG antibodies (HABIA) were detected in 99 out of 104 sera from blood donors (50 females; 54 males). HABIA levels in male sera (n = 54......) were positively correlated to the false positive signals in the PP14 ELISA (r = 0.923; p detected in the donor sera, but levels and frequencies were lower compared to that of HABIA. Furthermore, HABIA were...

  20. Human IgG Antibody Response to Aedes Nterm-34kDa Salivary Peptide, an Epidemiological Tool to Assess Vector Control in Chikungunya and Dengue Transmission Area.

    Science.gov (United States)

    Elanga Ndille, Emmanuel; Doucoure, Souleymane; Poinsignon, Anne; Mouchet, François; Cornelie, Sylvie; D'Ortenzio, Eric; DeHecq, Jean Sébastien; Remoue, Franck

    2016-12-01

    Arboviral diseases are an important public health concerns. Vector control remains the sole strategy to fight against these diseases. Because of the important limits of methods currently used to assess human exposure to Aedes mosquito bites, much effort is being devoted to develop new indicators. Recent studies have reported that human antibody (Ab) responses to Aedes aegypti Nterm-34kDa salivary peptide represent a promising biomarker tool to evaluate the human-Aedes contact. The present study aims investigate whether such biomarker could be used for assessing the efficacy of vector control against Aedes. Specific human IgG response to the Nterm-34kDa peptide was assessed from 102 individuals living in urban area of Saint-Denis at La Reunion Island, Indian Ocean, before and after the implementation of vector control against Aedes mosquitoes. IgG response decreased after 2 weeks (P Aedes mosquito density, as estimated by entomological parameters and closely correlated to vector control implementation and was not associated with the use of individual protection, daily commuting outside of the house, sex and age. Our findings indicate a probable short-term decrease of human exposure to Aedes bites just after vector control implementation. Results provided in the present study indicate that IgG Ab response to Aedes aegypti Nterm-34kDa salivary peptide could be a relevant short-time indicator for evaluating the efficacy of vector control interventions against Aedes species.

  1. Enhanced insight into the autoimmune component of glaucoma: IgG autoantibody accumulation and pro-inflammatory conditions in human glaucomatous retina.

    Science.gov (United States)

    Gramlich, Oliver W; Beck, Sabine; von Thun Und Hohenstein-Blaul, Nadine; Boehm, Nils; Ziegler, Anika; Vetter, Jan M; Pfeiffer, Norbert; Grus, Franz H

    2013-01-01

    There is accumulating evidence that autoimmune components, such as autoantibodies and autoantibody depositions, play a role in the pathogenesis of neurodegenerative diseases like Alzheimeŕs disease or Multiple Sclerosis. Due to alterations of autoantibody patterns in sera and aqueous humor, an autoimmune component is also assumed in the pathogenesis of glaucoma, a common reason for irreversible blindness worldwide. So far there has been no convincing evidence that autoantibodies are accumulated in the retina of glaucoma patients and that the local immune homeostasis might be affected. Six human glaucomatous donor eyes and nine samples from donors with no recorded ocular disease were included. Antibody microarrays were used to examine the patterns of pro-inflammatory proteins and complement proteins. Analysis of TNF-α and interleukin levels revealed a slight up-regulation exclusively in the glaucomatous group, while complement protein levels were not altered. IgG autoantibody accumulations and/or cellular components were determined by immunohistology (n = 4 per group). A significantly reduced number of retinal ganglion cells was found in the glaucomatous group (healthy: 104±7 nuclei/mm, glaucoma: 67±9 nuclei/mm; p = 0.0007). Cell loss was accompanied by strong retinal IgG autoantibody accumulations, which were at least twice as high as in healthy subjects (healthy: 5.0±0.5 IgG deposits/100 cells, glaucoma: 9.4±1.9 IgG deposits/100 cells; p = 0.004). CD27(+) cells and CD27(+)/IgG(+) plasma cells were observed in all glaucomatous subjects, but not in controls. This work provides serious evidence for the occurrence of IgG antibody deposition and plasma cells in human glaucomatous retina. Moreover, the results suggest that these IgG deposits occurred in a pro-inflammatory environment which seems to be maintained locally by immune-competent cells like microglia. Thereby, glaucoma features an immunological involvement comparable to other

  2. Enhanced insight into the autoimmune component of glaucoma: IgG autoantibody accumulation and pro-inflammatory conditions in human glaucomatous retina.

    Directory of Open Access Journals (Sweden)

    Oliver W Gramlich

    Full Text Available BACKGROUND: There is accumulating evidence that autoimmune components, such as autoantibodies and autoantibody depositions, play a role in the pathogenesis of neurodegenerative diseases like Alzheimeŕs disease or Multiple Sclerosis. Due to alterations of autoantibody patterns in sera and aqueous humor, an autoimmune component is also assumed in the pathogenesis of glaucoma, a common reason for irreversible blindness worldwide. So far there has been no convincing evidence that autoantibodies are accumulated in the retina of glaucoma patients and that the local immune homeostasis might be affected. METHODS AND RESULTS: Six human glaucomatous donor eyes and nine samples from donors with no recorded ocular disease were included. Antibody microarrays were used to examine the patterns of pro-inflammatory proteins and complement proteins. Analysis of TNF-α and interleukin levels revealed a slight up-regulation exclusively in the glaucomatous group, while complement protein levels were not altered. IgG autoantibody accumulations and/or cellular components were determined by immunohistology (n = 4 per group. A significantly reduced number of retinal ganglion cells was found in the glaucomatous group (healthy: 104±7 nuclei/mm, glaucoma: 67±9 nuclei/mm; p = 0.0007. Cell loss was accompanied by strong retinal IgG autoantibody accumulations, which were at least twice as high as in healthy subjects (healthy: 5.0±0.5 IgG deposits/100 cells, glaucoma: 9.4±1.9 IgG deposits/100 cells; p = 0.004. CD27(+ cells and CD27(+/IgG(+ plasma cells were observed in all glaucomatous subjects, but not in controls. CONCLUSION: This work provides serious evidence for the occurrence of IgG antibody deposition and plasma cells in human glaucomatous retina. Moreover, the results suggest that these IgG deposits occurred in a pro-inflammatory environment which seems to be maintained locally by immune-competent cells like microglia. Thereby, glaucoma features an

  3. Sialylated Autoantigen-Reactive IgG Antibodies Attenuate Disease Development in Autoimmune Mouse Models of Lupus Nephritis and Rheumatoid Arthritis

    Directory of Open Access Journals (Sweden)

    Yannic C. Bartsch

    2018-06-01

    Full Text Available Pro- and anti-inflammatory effector functions of IgG antibodies (Abs depend on their subclass and Fc glycosylation pattern. Accumulation of non-galactosylated (agalactosylated; G0 IgG Abs in the serum of rheumatoid arthritis and systemic lupus erythematosus (SLE patients reflects severity of the diseases. In contrast, sialylated IgG Abs are responsible for anti-inflammatory effects of the intravenous immunoglobulin (pooled human serum IgG from healthy donors, administered in high doses (2 g/kg to treat autoimmune patients. However, whether low amounts of sialylated autoantigen-reactive IgG Abs can also inhibit autoimmune diseases is hardly investigated. Here, we explore whether sialylated autoantigen-reactive IgG Abs can inhibit autoimmune pathology in different mouse models. We found that sialylated IgG auto-Abs fail to induce inflammation and lupus nephritis in a B cell receptor (BCR transgenic lupus model, but instead are associated with lower frequencies of pathogenic Th1, Th17 and B cell responses. In accordance, the transfer of small amounts of immune complexes containing sialylated IgG Abs was sufficient to attenuate the development of nephritis. We further showed that administration of sialylated collagen type II (Col II-specific IgG Abs attenuated the disease symptoms in a model of Col II-induced arthritis and reduced pathogenic Th17 cell and autoantigen-specific IgG Ab responses. We conclude that sialylated autoantigen-specific IgG Abs may represent a promising tool for treating pathogenic T and B cell immune responses in autoimmune diseases.

  4. Conformational destabilization of Immunoglobulin G increases the low pH-binding affinity with the Neonatal Fc Receptor

    DEFF Research Database (Denmark)

    Walters, Benjamin T; Jensen, Pernille Foged; Larraillet, Vincent

    2016-01-01

    Crystallographic evidence suggests that the pH-dependent affinity of IgG molecules for the neonatal Fc receptor (FcRn) receptor primarily arises from salt bridges involving IgG histidine residues, resulting in moderate affinity at mildly acidic conditions. However, this view does not explain the ......H-dependent affinity in IgG-FcRn interactions and exemplify the important and often ignored role of intrinsic conformational dynamics in a protein ligand, to dictate affinity for biologically important receptors.......Crystallographic evidence suggests that the pH-dependent affinity of IgG molecules for the neonatal Fc receptor (FcRn) receptor primarily arises from salt bridges involving IgG histidine residues, resulting in moderate affinity at mildly acidic conditions. However, this view does not explain...... the diversity in affinity found in IgG variants, such as the YTE mutant (M252Y,S254T,T256E), which increases affinity to FcRn by up to 10×. Here we compare hydrogen exchange measurements at pH 7.0 and pH 5.5 with and without FcRn bound with surface plasmon resonance estimates of dissociation constants and Fc...

  5. Inhibition of th17 cells and promotion of tregs in fc gamma chain-deficient mice contributes to the attenuated atherosclerotic lesions

    Science.gov (United States)

    The presence of anti-oxLDL IgG is well documented in clinical and animal studies. However, the role for Fc Rs to the progression of atherosclerosis has not been studied in detail. In the present study, we investigated the role for activating Fc R in the progression of atherosclerosis using apoE-Fc -...

  6. A fully human IgG1 anti-PD-L1 MAb in an in vitro assay enhances antigen-specific T-cell responses

    OpenAIRE

    Grenga, Italia; Donahue, Renee N; Lepone, Lauren M; Richards, Jacob; Schlom, Jeffrey

    2016-01-01

    Monoclonal antibodies (MAbs) that interfere with checkpoint molecules are being investigated for the treatment of infectious diseases and cancer, with the aim of enhancing the function of an impaired immune system. Avelumab (MSB0010718C) is a fully human IgG1 MAb targeting programmed death-ligand 1 (PD-L1), which differs from other checkpoint-blocking antibodies in its ability to mediate antibody-dependent cell-mediated cytotoxicity. These studies were conducted to define whether avelumab cou...

  7. A novel TNFα antagonizing peptide-Fc fusion protein designed based on CDRs of TNFα neutralizing monoclonal antibody

    International Nuclear Information System (INIS)

    Qin Weisong; Feng Jiannan; Zhang Wei; Li Yan; Shen, Beifen

    2004-01-01

    The variable regions of antibody molecules bind antigens with high affinity and specificity. The binding sites are imparted largely to the hypervariable portions (i.e., CDRs) of the variable region. Peptides derived from CDRs can bind antigen with similar specificity acting as mimic of antibody and become drug-designing core, although with markedly lower affinity. In order to increase the affinity and bioactivity, in this study, a novel peptide (PT) designed on CDRs of a TNFα neutralizing monoclonal antibody Z12 was linked with Fc fragment of human IgG1. The interaction mode of PT-linker-Fc (PLF) with TNFα was analyzed with computer-guided molecular modeling method. After expression in Escherichia coli and purification, recombinant PT-linker-Fc could bind directly with the TNFα coated on the ELISA plates. Furthermore, PLF could competitively inhibit the binding of Z12 to TNFα and also inhibit the TNFα-induced cytotoxicity on L929 cells. The TNFα antagonizing activity of PLF was significantly higher than that of the free peptide. This study highlights the potential of human Fc to enhance the potency of peptides designed on the CDRs of antibodies and could be useful in developing new TNFα antagonists

  8. Induction of functional Fc receptors in P388 leukemia cells. Requirement for multiple differentiation signals.

    Science.gov (United States)

    Cohen, D A; Stotelmyer, N L; Kaplan, A M

    1985-04-01

    The development of functional Fc receptors (FcR) during induced differentiation with the tumor promoter, phorbol myristate acetate (PMA), was studied in the murine tumor cell line, P388. PMA induced the appearance of FcR on the membranes of P388 cells as indicated by the binding of IgG-coated sheep red blood cells (IgG-SRBC). Concentrations of PMA as low as 1 ng/ml were sufficient to induce the expression of FcR as well as to inhibit cellular division and to induce adherence in the P388 tumor cell line; however, optimal FcR induction occurred at PMA concentrations of 10-100 ng/ml. Immunofluorescent analysis with heat-aggregated myeloma proteins indicated that PMA induced FcR which were capable of binding IgG2a and IgG2b immunoglobulins, but not IgG1. Adherence to a substratum was determined to be a second required signal for expression of FcR, since PMA induction of P388 tumor cells in teflon dishes failed to fully develop FcR and adherence of P388 cells to poly-L-lysine-coated culture dishes in the absence of PMA was insufficient for FcR expression. FcR which appeared after PMA induction were non-functional in the sense that membrane-bound IgG-SRBC were not ingested to any significant extent by the tumor cells. However, if FcR induction occurred in the presence conA-induced rat spleen cell culture supernatants, phagocytosis of membrane-bound erythrocytes occurred. These findings suggest that for the expression of FcR which are capable of particle internalization, at least three identifiable membrane-transmitted signals are required during differentiation.

  9. Studies of nontarget-mediated distribution of human full-length IgG1 antibody and its FAb fragment in cardiovascular and metabolic-related tissues.

    Science.gov (United States)

    Davidsson, Pia; Söderling, Ann-Sofi; Svensson, Lena; Ahnmark, Andrea; Flodin, Christine; Wanag, Ewa; Screpanti-Sundqvist, Valentina; Gennemark, Peter

    2015-05-01

    Tissue distribution and pharmacokinetics (PK) of full-length nontargeted antibody and its antigen-binding fragment (FAb) were evaluated for a range of tissues primarily of interest for cardiovascular and metabolic diseases. Mice were intravenously injected with a dose of 10 mg/kg of either human IgG1or its FAb fragment; perfused tissues were collected at a range of time points over 3 weeks for the human IgG1 antibody and 1 week for the human FAb antibody. Tissues were homogenized and antibody concentrations were measured by specific immunoassays on the Gyros system. Exposure in terms of maximum concentration (Cmax ) and area under the curve was assessed for all nine tissues. Tissue exposure of full-length antibody relative to plasma exposure was found to be between 1% and 10%, except for brain (0.2%). Relative concentrations of FAb antibody were the same, except for kidney tissue, where the antibody concentration was found to be ten times higher than in plasma. However, the absolute tissue uptake of full-length IgG was significantly higher than the absolute tissue uptake of the FAb antibody. This study provides a reference PK state for full-length whole and FAb antibodies in tissues related to cardiovascular and metabolic diseases that do not include antigen or antibody binding. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  10. Cetuximab in combination with anti-human IgG antibodies efficiently down-regulates the EGF receptor by macropinocytosis

    International Nuclear Information System (INIS)

    Berger, Christian; Madshus, Inger Helene; Stang, Espen

    2012-01-01

    The monoclonal antibody C225 (Cetuximab) blocks binding of ligand to the epidermal growth factor receptor (EGFR). In addition, it is known that incubation with C225 induces endocytosis of the EGFR. This endocytosis has previously been shown to be increased when C225 is combined with an additional monoclonal anti-EGFR antibody. However, the effects of antibody combinations on EGFR activation, endocytosis, trafficking and degradation have been unclear. By binding a secondary antibody to the C225-EGFR complex, we here demonstrate that a combination of antibodies can efficiently internalize and degrade the EGFR. Although the combination of antibodies activated the EGFR kinase and induced ubiquitination of the EGFR, the kinase activity was not required for internalization of the EGFR. In contrast to EGF-induced EGFR down-regulation, the antibody combination efficiently degraded the EGFR without initiating downstream proliferative signaling. The antibody-induced internalization of EGFR was found not to depend on clathrin and/or dynamin, but depended on actin polymerization, suggesting induction of macropinocytosis. Macropinocytosis may cause internalization of large membrane areas, and this could explain the highly efficient internalization of the EGFR induced by combination of antibodies. -- Highlight: ► Cetuximab induced endocytosis of EGFR increases upon combination with anti-human IgG. ► Antibody combination causes internalization of EGFR by macropinocytosis. ► Antibody-induced internalization of EGFR is independent of EGFR kinase activity. ► Antibody combination may have a zipper effect and cross-link EGFRs on neighboring cells.

  11. Cetuximab in combination with anti-human IgG antibodies efficiently down-regulates the EGF receptor by macropinocytosis

    Energy Technology Data Exchange (ETDEWEB)

    Berger, Christian [Department of Pathology, Oslo University Hospital, Rikshospitalet, Post box 4950 Nydalen, 0424 Oslo (Norway); Madshus, Inger Helene [Institute of Pathology, University of Oslo, Rikshospitalet, 0027 Oslo (Norway); Department of Pathology, Oslo University Hospital, Rikshospitalet, Post box 4950 Nydalen, 0424 Oslo (Norway); Stang, Espen, E-mail: espsta@rr-research.no [Department of Pathology, Oslo University Hospital, Rikshospitalet, Post box 4950 Nydalen, 0424 Oslo (Norway)

    2012-12-10

    The monoclonal antibody C225 (Cetuximab) blocks binding of ligand to the epidermal growth factor receptor (EGFR). In addition, it is known that incubation with C225 induces endocytosis of the EGFR. This endocytosis has previously been shown to be increased when C225 is combined with an additional monoclonal anti-EGFR antibody. However, the effects of antibody combinations on EGFR activation, endocytosis, trafficking and degradation have been unclear. By binding a secondary antibody to the C225-EGFR complex, we here demonstrate that a combination of antibodies can efficiently internalize and degrade the EGFR. Although the combination of antibodies activated the EGFR kinase and induced ubiquitination of the EGFR, the kinase activity was not required for internalization of the EGFR. In contrast to EGF-induced EGFR down-regulation, the antibody combination efficiently degraded the EGFR without initiating downstream proliferative signaling. The antibody-induced internalization of EGFR was found not to depend on clathrin and/or dynamin, but depended on actin polymerization, suggesting induction of macropinocytosis. Macropinocytosis may cause internalization of large membrane areas, and this could explain the highly efficient internalization of the EGFR induced by combination of antibodies. -- Highlight: Black-Right-Pointing-Pointer Cetuximab induced endocytosis of EGFR increases upon combination with anti-human IgG. Black-Right-Pointing-Pointer Antibody combination causes internalization of EGFR by macropinocytosis. Black-Right-Pointing-Pointer Antibody-induced internalization of EGFR is independent of EGFR kinase activity. Black-Right-Pointing-Pointer Antibody combination may have a zipper effect and cross-link EGFRs on neighboring cells.

  12. High-yield production of a human monoclonal IgG by rhizosecretion in hydroponic tobacco cultures.

    Science.gov (United States)

    Madeira, Luisa M; Szeto, Tim H; Henquet, Maurice; Raven, Nicole; Runions, John; Huddleston, Jon; Garrard, Ian; Drake, Pascal M W; Ma, Julian K-C

    2016-02-01

    Rhizosecretion of recombinant pharmaceuticals from in vitro hydroponic transgenic plant cultures is a simple, low cost, reproducible and controllable production method. Here, we demonstrate the application and adaptation of this manufacturing platform to a human antivitronectin IgG1 monoclonal antibody (mAb) called M12. The rationale for specific growth medium additives was established by phenotypic analysis of root structure and by LC-ESI-MS/MS profiling of the total protein content profile of the hydroponic medium. Through a combination of optimization approaches, mAb yields in hydroponic medium reached 46 μg/mL in 1 week, the highest figure reported for a recombinant mAb in a plant secretion-based system to date. The rhizosecretome was determined to contain 104 proteins, with the mAb heavy and light chains the most abundant. This enabled evaluation of a simple, scalable extraction and purification protocol and demonstration that only minimal processing was necessary prior to protein A affinity chromatography. MALDI-TOF MS revealed that purified mAb contained predominantly complex-type plant N-glycans, in three major glycoforms. The binding of M12 purified from hydroponic medium to vitronectin was comparable to its Chinese hamster ovary (CHO)-derived counterpart. This study demonstrates that in vitro hydroponic cultivation coupled with recombinant protein rhizosecretion can be a practical, low-cost production platform for monoclonal antibodies. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  13. Snake venomics of monocled cobra (Naja kaouthia) and investigation of human IgG response against venom toxins

    DEFF Research Database (Denmark)

    Laustsen, Andreas Hougaard; Gutiérrez, José María; Lohse, Brian

    2015-01-01

    /cardiotoxins. IgGs isolated from a person who had repeatedly self-immunized with a variety of snake venoms were immunoprofiled by ELISA against all venom fractions. Stronger responses against larger toxins, but lower against the most critical α-neurotoxins were obtained. As expected, no neutralization potential...

  14. Differential expression of IgE and IgG4 specific antibody responses in asymptomatic and chronic human filariasis

    NARCIS (Netherlands)

    Kurniawan, A.; Yazdanbakhsh, M.; van Ree, R.; Aalberse, R.; Selkirk, M. E.; Partono, F.; Maizels, R. M.

    1993-01-01

    A population of 164 adult individuals resident in an area endemic for Brugia malayi lymphatic filariasis has been studied for humoral immune responses to filarial parasites. Antibody levels to Ag extracted from adult worms were determined for each of the IgG subclasses, for IgM and for IgE. The

  15. Role of IgG4 in histamine release from human basophil leucocytes. I. Sensitization of cells from normal donors

    DEFF Research Database (Denmark)

    Poulsen, L K; Stahl Skov, P; Mosbech, H

    1988-01-01

    Several conflicting reports on the ability of IgG4 to mediate type I allergic reactions have appeared lately. We have developed a model system for testing this possibility, using passive sensitization of basophil leucocytes from normal individuals. At first, the system was optimized with regard t...

  16. Activation of human natural killer cells by the soluble form of cellular prion protein

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Yeon-Jae [Laboratory of Immunology and Infectious Diseases, Graduate School of Medical Science and Engineering, KAIST, Daejeon (Korea, Republic of); Hafis Clinic, Seoul (Korea, Republic of); Sung, Pil Soo; Jang, Young-Soon; Choi, Young Joon [Laboratory of Immunology and Infectious Diseases, Graduate School of Medical Science and Engineering, KAIST, Daejeon (Korea, Republic of); Park, Bum-Chan [Aging Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Park, Su-Hyung [Laboratory of Translational Immunology and Vaccinology, Graduate School of Medical Science and Engineering, KAIST, Daejeon (Korea, Republic of); Park, Young Woo [Aging Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Shin, Eui-Cheol, E-mail: ecshin@kaist.ac.kr [Laboratory of Immunology and Infectious Diseases, Graduate School of Medical Science and Engineering, KAIST, Daejeon (Korea, Republic of)

    2015-08-21

    Cellular prion protein (PrP{sup C}) is widely expressed in various cell types, including cells of the immune system. However, the specific roles of PrP{sup C} in the immune system have not been clearly elucidated. In the present study, we investigated the effects of a soluble form of recombinant PrP{sup C} protein on human natural killer (NK) cells. Recombinant soluble PrP{sup C} protein was generated by fusion of human PrP{sup C} with the Fc portion of human IgG{sub 1} (PrP{sup C}-Fc). PrP{sup C}-Fc binds to the surface of human NK cells, particularly to CD56{sup dim} NK cells. PrP{sup C}-Fc induced the production of cytokines and chemokines and the degranulation of granzyme B from NK cells. In addition, PrP{sup C}-Fc facilitated the IL-15-induced proliferation of NK cells. PrP{sup C}-Fc induced phosphorylation of ERK-1/2 and JNK in NK cells, and inhibitors of the ERK or the JNK pathways abrogated PrP{sup C}-Fc-induced cytokine production in NK cells. In conclusion, the soluble form of recombinant PrP{sup C}-Fc protein activates human NK cells via the ERK and JNK signaling pathways. - Highlights: • Recombinant soluble PrP{sup C} (PrP{sup C}-Fc) was generated by fusion of human PrP{sup C} with IgG1 Fc portion. • PrP{sup C}-Fc protein induces the production of cytokines and degranulation from human NK cells. • PrP{sup C}-Fc protein enhances the IL-15-induced proliferation of human NK cells. • PrP{sup C}-Fc protein activates human NK cells via the ERK and JNK signaling pathways.

  17. Aspergillus Cell Wall Chitin Induces Anti- and Proinflammatory Cytokines in Human PBMCs via the Fc-γ Receptor/Syk/PI3K Pathway

    Science.gov (United States)

    Becker, K. L.; Aimanianda, V.; Wang, X.; Gresnigt, M. S.; Ammerdorffer, A.; Jacobs, C. W.; Gazendam, R. P.; Joosten, L. A. B.; Netea, M. G.

    2016-01-01

    ABSTRACT Chitin is an important cell wall component of Aspergillus fumigatus conidia, of which hundreds are inhaled on a daily basis. Previous studies have shown that chitin has both anti- and proinflammatory properties; however the exact mechanisms determining the inflammatory signature of chitin are poorly understood, especially in human immune cells. Human peripheral blood mononuclear cells were isolated from healthy volunteers and stimulated with chitin from Aspergillus fumigatus. Transcription and production of the proinflammatory cytokine interleukin-1β (IL-1β) and the anti-inflammatory cytokine IL-1 receptor antagonist (IL-1Ra) were measured from the cell culture supernatant by quantitative PCR (qPCR) or enzyme-linked immunosorbent assay (ELISA), respectively. Chitin induced an anti-inflammatory signature characterized by the production of IL-1Ra in the presence of human serum, which was abrogated in immunoglobulin-depleted serum. Fc-γ-receptor-dependent recognition and phagocytosis of IgG-opsonized chitin was identified as a novel IL-1Ra-inducing mechanism by chitin. IL-1Ra production induced by chitin was dependent on Syk kinase and phosphatidylinositol 3-kinase (PI3K) activation. In contrast, costimulation of chitin with the pattern recognition receptor (PRR) ligands lipopolysaccharide, Pam3Cys, or muramyl dipeptide, but not β-glucan, had synergistic effects on the induction of proinflammatory cytokines by human peripheral blood mononuclear cells (PBMCs). In conclusion, chitin can have both pro- and anti-inflammatory properties, depending on the presence of pathogen-associated molecular patterns and immunoglobulins, thus explaining the various inflammatory signatures reported for chitin. PMID:27247234

  18. Fc gamma receptor activation induces the tyrosine phosphorylation of both phospholipase C (PLC)-gamma 1 and PLC-gamma 2 in natural killer cells

    OpenAIRE

    1992-01-01

    Crosslinking of the low affinity immunoglobulin G (IgG) Fc receptor (Fc gamma R type III) on natural killer (NK) cells initiates antibody- dependent cellular cytotoxicity. During this process, Fc gamma R stimulation results in the rapid activation of phospholipase C (PLC), which hydrolyzes membrane phosphoinositides, generating inositol-1,4,5- trisphosphate and sn-1,2-diacylglycerol as second messengers. We have recently reported that PLC activation after Fc gamma R stimulation can be inhibit...

  19. A freeze dried kit formulation for the preparation of 99m Tc labelled human polyclonal IgG for the detection of infection and inflammation

    International Nuclear Information System (INIS)

    Pedraza L, M.

    1996-01-01

    A freeze dried kit formulation for the preparation of 99m Tc-labelled human polyclonal IgG for the detection of infection and inflammation employing direct methods for protein labeling was developed. The method comprises reduction of intrinsic disulphide bridges within the antibody molecule by the use of the reductant 2-mercaptoethanol. Following a subsequent purification, the resulting reduced antibody is labeled via Sn 2+ reduction of pertechnetate in the presence of a weak competing ligand ethane-1-hydroxy-1,1-diphosphonate (EHDP). High labeling efficiencies (>90%) were obtained with high in vitro stability and without effect upon antibody immunoreactivity. Methods of analysis were also established permitting identification of radiochemical impurities which may be present in radiopharmaceutical solution. 99m Tc-polyclonal IgG prepared by the kit method was evaluated for scintigraphic localization of inflammatory lesions and abscesses in rabbits. Data demonstrated that the 99m Tc-polyclonal IgG after kit-reconstitution shows excellent stability and is an effective imaging agent of infection and/or inflammation. (Author)

  20. Radiolabeled Humanized Anti-CD3 Monoclonal Antibody Visilizumab for Imaging Human T-Lymphocytes

    NARCIS (Netherlands)

    Malviya, Gaurav; D'Alessandria, Calogero; Bonanno, Elena; Vexler, Vladimir; Massari, Roberto; Trotta, Carlo; Scopinaro, Francesco; Dierckx, Rudi; Signore, Alberto

    2009-01-01

    Visilizumab is an IgG(2) humanized monoclonal antibody (mAb) characterized by non-Fc gamma R binding and specific to the CD3 antigen, expressed on more than 95% of circulating resting T-lymphocytes and on activated T-lymphocytes homing in inflamed tissues. We hypothesized that the use of a

  1. Immunization With Fc-Based Recombinant Epstein–Barr Virus gp350 Elicits Potent Neutralizing Humoral Immune Response in a BALB/c Mice Model

    Directory of Open Access Journals (Sweden)

    Bingchun Zhao

    2018-05-01

    Full Text Available Epstein–Barr virus (EBV was the first human virus proved to be closely associated with tumor development, such as lymphoma, nasopharyngeal carcinoma, and EBV-associated gastric carcinoma. Despite many efforts to develop prophylactic vaccines against EBV infection and diseases, no candidates have succeeded in effectively blocking EBV infection in clinical trials. Previous investigations showed that EBV gp350 plays a pivotal role in the infection of B-lymphocytes. Nevertheless, using monomeric gp350 proteins as antigens has not been effective in preventing infection. Multimeric forms of the antigen are more potently immunogenic than monomers; however, the multimerization elements used in previous constructs are not approved for human clinical trials. To prepare a much-needed EBV prophylactic vaccine that is potent, safe, and applicable, we constructed an Fc-based form of gp350 to serve as a dimeric antigen. Here, we show that the Fc-based gp350 antigen exhibits dramatically enhanced immunogenicity compared with wild-type gp350 protein. The complete or partial gp350 ectodomain was fused with the mouse IgG2a Fc domain. Fusion with the Fc domain did not impair gp350 folding, binding to a conformation-dependent neutralizing antibody (nAb and binding to its receptor by enzyme-linked immunosorbent assay and surface plasmon resonance. Specific antibody titers against gp350 were notably enhanced by immunization with gp350-Fc dimers compared with gp350 monomers. Furthermore, immunization with gp350-Fc fusion proteins elicited potent nAbs against EBV. Our data strongly suggest that an EBV gp350 vaccine based on Fc fusion proteins may be an efficient candidate to prevent EBV infection in clinical applications.

  2. TTI-621 (SIRPαFc): A CD47-Blocking Innate Immune Checkpoint Inhibitor with Broad Antitumor Activity and Minimal Erythrocyte Binding.

    Science.gov (United States)

    Petrova, Penka S; Viller, Natasja Nielsen; Wong, Mark; Pang, Xinli; Lin, Gloria H Y; Dodge, Karen; Chai, Vien; Chen, Hui; Lee, Vivian; House, Violetta; Vigo, Noel T; Jin, Debbie; Mutukura, Tapfuma; Charbonneau, Marilyse; Truong, Tran; Viau, Stephane; Johnson, Lisa D; Linderoth, Emma; Sievers, Eric L; Maleki Vareki, Saman; Figueredo, Rene; Pampillo, Macarena; Koropatnick, James; Trudel, Suzanne; Mbong, Nathan; Jin, Liqing; Wang, Jean C Y; Uger, Robert A

    2017-02-15

    Purpose: The ubiquitously expressed transmembrane glycoprotein CD47 delivers an anti-phagocytic (do not eat) signal by binding signal-regulatory protein α (SIRPα) on macrophages. CD47 is overexpressed in cancer cells and its expression is associated with poor clinical outcomes. TTI-621 (SIRPαFc) is a fully human recombinant fusion protein that blocks the CD47-SIRPα axis by binding to human CD47 and enhancing phagocytosis of malignant cells. Blockade of this inhibitory axis using TTI-621 has emerged as a promising therapeutic strategy to promote tumor cell eradication. Experimental Design: The ability of TTI-621 to promote macrophage-mediated phagocytosis of human tumor cells was assessed using both confocal microscopy and flow cytometry. In vivo antitumor efficacy was evaluated in xenograft and syngeneic models and the role of the Fc region in antitumor activity was evaluated using SIRPαFc constructs with different Fc tails. Results: TTI-621 enhanced macrophage-mediated phagocytosis of both hematologic and solid tumor cells, while sparing normal cells. In vivo , TTI-621 effectively controlled the growth of aggressive AML and B lymphoma xenografts and was efficacious in a syngeneic B lymphoma model. The IgG1 Fc tail of TTI-621 plays a critical role in its antitumor activity, presumably by engaging activating Fcγ receptors on macrophages. Finally, TTI-621 exhibits minimal binding to human erythrocytes, thereby differentiating it from CD47 blocking antibodies. Conclusions: These data indicate that TTI-621 is active across a broad range of human tumors. These results further establish CD47 as a critical regulator of innate immune surveillance and form the basis for clinical development of TTI-621 in multiple oncology indications. Clin Cancer Res; 23(4); 1068-79. ©2016 AACR . ©2016 American Association for Cancer Research.

  3. 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...

  4. Study on immobilizations of ovine anti-human IgG and MCAb against EHF on radiation-modified silicone films

    Energy Technology Data Exchange (ETDEWEB)

    Jinhui, Guo; Hongfei, Ha; Yuhua, Zhang [Beijing Univ., BJ (China). Dept. of Technical Physics

    1990-08-01

    Films of silicone (silastic) were grafted by monomer acrylamide vis {gamma}-radiation technology and then the ovine anti-human IgG, Epidemic hemorrhagic fever (EHF)-MCAb were immobilized on the silastic-AAM films with different grafting yields passthrough associate reactions. Measruements of relationships between grafting yields. Contents of immobilized antibodies and immunoactivities for immobilized silastic-AAM films were performed by using {sup 125}I method ELISA method was used to measure the immunoactivities for the immobilized monoantibody. The results showed that the antibodies used can be immobilized on radiation-grafted silicone films and this immobilization method has its potential significance in clinical practice.

  5. Study on immobilizations of ovine anti-human IgG and MCAb against EHF on radiation-modified silicone films

    International Nuclear Information System (INIS)

    Guo Jinhui; Ha Hongfei; Zhang Yuhua

    1990-01-01

    Films of silicone (silastic) were grafted by monomer acrylamide vis γ-radiation technology and then the ovine anti-human IgG, Epidemic hemorrhagic fever (EHF)-MCAb were immobilized on the silastic-AAM films with different grafting yields passthrough associate reactions. Measruements of relationships between grafting yields. Contents of immobilized antibodies and immunoactivities for immobilized silastic-AAM films were performed by using 125 I method ELISA method was used to measure the immunoactivities for the immobilized monoantibody. The results showed that the antibodies used can be immobilized on radiation-grafted silicone films and this immobilization method has its potential significance in clinical practice

  6. The effect of FcγRIIA and FcγRIIB on coronary artery lesion formation and intravenous immunoglobulin treatment responses in children with Kawasaki disease

    Science.gov (United States)

    Chang, Ling-Sai; Lo, Mao-Hung; Li, Sung-Chou; Yang, Ming-Yu; Hsieh, Kai-Sheng; Kuo, Ho-Chang

    2017-01-01

    Previous research has found patients with the FcγRIIIB NA1 variant having increased risk of intravenous immunoglobulin (IVIG) resistance in Kawasaki disease (KD). Our previous studies revealed that elevated FcγRIIA expression correlated with the susceptibility of KD patients. We conducted this research to determine whether and how Fcγ receptors affect the susceptibility, IVIG treatment response, and coronary artery lesions (CAL) of KD patients. The activating FcγRIIA and inhibitory FcγRIIB methylation levels of seven patients with KD and four control subjects were examined using HumanMethylation27 BeadChip. We enrolled a total of 44 KD patients and 10 control subjects with fevers. We performed real-time RT-PCR to determine the FcγRIIA and FcγRIIB expression levels, as well as a luciferase assay of FcγRIIA. We found a considerable increase in methylation of both FcγRIIA and FcγRIIB in KD patients undergoing IVIG treatment. Promoter methylation of FcγRIIA inhibited reporter activity in K562 cells using luciferase assay. The FcγRIIB mRNA expression levels were not found to increase susceptibility, CAL formation, or IVIG resistance. FcγRIIA mRNA expression levels were significantly higher in IVIG-resistant patients than in those that responded to IVIG during the pre-treatment period. Furthermore, the FcγRIIA/IIB mRNA expression ratio was considerably higher in KD patients with CAL than in those without CAL. FcγRIIA and FcγRIIB both demonstrated increased methylation levels in KD patients that underwent IVIG treatment. FcγRIIA expression influenced the IVIG treatment response of KD patients. The FcγRIIA/IIB mRNA expression ratio was greater in KD patients with CAL formation. PMID:27893416

  7. Expression, purification and characterization of the recombinant chimeric IgE Fc-fragment opossum-human-opossum (OSO), an active immunotherapeutic vaccine component.

    Science.gov (United States)

    Xu, Bingze; Lundgren, Mats; Magnusson, Ann-Christine; Fuentes, Alexis

    2010-11-01

    The active vaccine component recombinant chimeric IgE Fc-fragment opossum-human-opossum (OSO) has been expressed in CHO-K1 cells. It contains two identical polypeptide chains with 338 amino acid residues in each chain connected by two disulfide bridges. The cell lines were adapted to suspension culture in a serum-free medium. An expression level of 60 mg/L was obtained after 8 days in a shaking flask at a temperature of 31.5 degrees C. The OSO protein has been purified to homogeneity by a combination of three chromatographic steps. Virus inactivation and reduction by solvent detergent treatment and nano-filtration were included in the process. The residual host cell protein content was less than 50 ng/mg OSO as analyzed by ELISA. Purity was analyzed by SDS-PAGE under reducing and non-reducing conditions and was estimated by densitometry to be above 99.0%. The dimer content was less than 0.1% as estimated by analytical size exclusion chromatography. The molecular mass, as estimated by SDS-PAGE, is 90 kDa. A value of around 74 kDa was calculated from its amino acid composition. This indicates that the protein is heavily glycosylated containing around 18% carbohydrate. Isoelectric focusing in polyacrylamide gel disclosed a ladder type band pattern with pI values in the pH-range 7.0-8.3, indicating a variation in the sialic acid content. The OSO protein is not stable at temperatures above 40 degrees C and at pH values below 4 indicating that virus inactivation by incubating the protein solution at higher temperature or at lower pH is not possible. Copyright 2010 Elsevier Inc. All rights reserved.

  8. Autoantibody-induced internalization of CNS AQP4 water channel and EAAT2 glutamate transporter requires astrocytic Fc receptor.

    Science.gov (United States)

    Hinson, Shannon R; Clift, Ian C; Luo, Ningling; Kryzer, Thomas J; Lennon, Vanda A

    2017-05-23

    Aquaporin-4 (AQP4) water channel-specific IgG distinguishes neuromyelitis optica (NMO) from multiple sclerosis and causes characteristic immunopathology in which central nervous system (CNS) demyelination is secondary. Early events initiating the pathophysiological outcomes of IgG binding to astrocytic AQP4 are poorly understood. CNS lesions reflect events documented in vitro following IgG interaction with AQP4: AQP4 internalization, attenuated glutamate uptake, intramyelinic edema, interleukin-6 release, complement activation, inflammatory cell recruitment, and demyelination. Here, we demonstrate that AQP4 internalization requires AQP4-bound IgG to engage an astrocytic Fcγ receptor (FcγR). IgG-lacking Fc redistributes AQP4 within the plasma membrane and induces interleukin-6 release. However, AQP4 endocytosis requires an activating FcγR's gamma subunit and involves astrocytic membrane loss of an inhibitory FcγR, CD32B. Interaction of the IgG-AQP4 complex with FcγRs triggers coendocytosis of the excitatory amino acid transporter 2 (EAAT2). Requirement of FcγR engagement for internalization of two astrocytic membrane proteins critical to CNS homeostasis identifies a complement-independent, upstream target for potential early therapeutic intervention in NMO.

  9. Optimization of photoactive protein Z for fast and efficient site-specific conjugation of native IgG.

    Science.gov (United States)

    Hui, James Z; Tsourkas, Andrew

    2014-09-17

    Antibody conjugates have been used in a variety of applications from immunoassays to drug conjugates. However, it is becoming increasingly clear that in order to maximize an antibody's antigen binding ability and to produce homogeneous antibody-conjugates, the conjugated molecule should be attached onto IgG site-specifically. We previously developed a facile method for the site-specific modification of full length, native IgGs by engineering a recombinant Protein Z that forms a covalent link to the Fc domain of IgG upon exposure to long wavelength UV light. To further improve the efficiency of Protein Z production and IgG conjugation, we constructed a panel of 13 different Protein Z variants with the UV-active amino acid benzoylphenylalanine (BPA) in different locations. By using this panel of Protein Z to cross-link a range of IgGs from different hosts, including human, mouse, and rat, we discovered two previously unknown Protein Z variants, L17BPA and K35BPA, that are capable of cross-linking many commonly used IgG isotypes with efficiencies ranging from 60% to 95% after only 1 h of UV exposure. When compared to existing site-specific methods, which often require cloning or enzymatic reactions, the Protein Z-based method described here, utilizing the L17BPA, K35BPA, and the previously described Q32BPA variants, represents a vastly more accessible and efficient approach that is compatible with nearly all native IgGs, thus making site-specific conjugation more accessible to the general research community.

  10. A novel antibody engineering strategy for making monovalent bispecific heterodimeric IgG antibodies by electrostatic steering mechanism.

    Science.gov (United States)

    Liu, Zhi; Leng, Esther C; Gunasekaran, Kannan; Pentony, Martin; Shen, Min; Howard, Monique; Stoops, Janelle; Manchulenko, Kathy; Razinkov, Vladimir; Liu, Hua; Fanslow, William; Hu, Zhonghua; Sun, Nancy; Hasegawa, Haruki; Clark, Rutilio; Foltz, Ian N; Yan, Wei

    2015-03-20

    Producing pure and well behaved bispecific antibodies (bsAbs) on a large scale for preclinical and clinical testing is a challenging task. Here, we describe a new strategy for making monovalent bispecific heterodimeric IgG antibodies in mammalian cells. We applied an electrostatic steering mechanism to engineer antibody light chain-heavy chain (LC-HC) interface residues in such a way that each LC strongly favors its cognate HC when two different HCs and two different LCs are co-expressed in the same cell to assemble a functional bispecific antibody. We produced heterodimeric IgGs from transiently and stably transfected mammalian cells. The engineered heterodimeric IgG molecules maintain the overall IgG structure with correct LC-HC pairings, bind to two different antigens with comparable affinity when compared with their parental antibodies, and retain the functionality of parental antibodies in biological assays. In addition, the bispecific heterodimeric IgG derived from anti-HER2 and anti-EGF receptor (EGFR) antibody was shown to induce a higher level of receptor internalization than the combination of two parental antibodies. Mouse xenograft BxPC-3, Panc-1, and Calu-3 human tumor models showed that the heterodimeric IgGs strongly inhibited tumor growth. The described approach can be used to generate tools from two pre-existent antibodies and explore the potential of bispecific antibodies. The asymmetrically engineered Fc variants for antibody-dependent cellular cytotoxicity enhancement could be embedded in monovalent bispecific heterodimeric IgG to make best-in-class therapeutic antibodies. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Chicken IgY Fc expressed by Eimeria mitis enhances the immunogenicity of E. mitis.

    Science.gov (United States)

    Qin, Mei; Tang, Xinming; Yin, Guangwen; Liu, Xianyong; Suo, Jingxia; Tao, Geru; Ei-Ashram, Saeed; Li, Yuan; Suo, Xun

    2016-03-21

    Eimeria species are obligate intracellular apicomplexan parasites, causing great economic losses in the poultry industry. Currently wild-and attenuated- type anticoccidial vaccines are used to control coccidiosis. However, their use in fast growing broilers is limited by vaccination side effects caused by medium and/or low immunogenic Eimeria spp. There is, therefore, a need for a vaccine with high immunogenicity for broilers. The avian yolk sac IgY Fc is the avian counterpart of the mammalian IgG Fc, which enhances immunogenicity of Fc-fusion proteins. Here, we developed a stable transgenic Eimeria mitis expressing IgY Fc (Emi.chFc) and investigated whether the avian IgY Fc fragment enhances the immunogenicity of E. mitis. Two-week-old broilers were immunized with either Emi.chFc or wild type Eimeria and challenged with wild type E. mitis to analyze the protective properties of transgenic Emi.chFc. Chickens immunized with Emi.chFc had significantly lower oocyst output, in comparison with PBS, mock control (transgenic E. mitis expressing HA1 from H9N2 avian influenza virus) and wildtype E. mitis immunized groups after challenge, indicating that IgY Fc enhanced the immunogenicity of E. mitis. Our findings suggest that IgY Fc-expressing Eimeria may be a better coccidiosis vaccine, and transgenic Eimeria expressing Fc-fused exogenous antigens may be used as a novel vaccine-delivery vehicle against a wide variety of pathogens.

  12. Detection of acute inflammation with 111In-labeled nonspecific polyclonal IgG

    International Nuclear Information System (INIS)

    Fischman, A.J.; Rubin, R.H.; Khaw, B.A.

    1988-01-01

    The detection of focal sites of inflammation is an integral part of the clinical evaluation of the febrile patient. When anatomically distinct abscesses are present, lesion detection can be accomplished by standard radiographic techniques, particularly in patients with normal anatomy. At the phlegmon stage, however, and in patients who have undergone surgery, these techniques are considerably less effective. While radionuclide methods, such as Gallium-67 (67Ga)-citrate and Indium-111 (111In)-labeled WBCs have been relatively successful for the detection of early inflammation, neither approach is ideal. In the course of studies addressing the use of specific organism-directed antibodies for imaging experimental infections in animals, we observed that nonspecific polyclonal immunoglobulin G (IgG) localized as well as specific antibodies. Preliminary experiments suggested that the Fc portion of IgG is necessary for effective inflammation localization. Since polyclonal IgG in gram quantities has been safely used for therapy in patients with immune deficiency states, we decided to test whether milligram quantities of radiolabeled IgG could image focal sites of inflammation in humans. Thus far, we have studied a series of 84 patients with suspected lesions in the abdomen, pelvis, vascular grafts, lungs, or bones/joints. In 48 of 52 patients with focal lesions detected by surgery, computed tomography (CT), magnetic resonance imaging (MRI), or ultrasound (US), the IgG scan correctly localized the site, while 31 patients without focal inflammation had no abnormal focal localization of the radiopharmaceutical. Four patients had false negative scans and one patient had a false positive scan. For this small series, the overall sensitivity and specificity were 92% and 95%, respectively. In this report, we review our experience with this exciting new agent

  13. Age-dependent association between IgG2 and IgG3 subclasses to Pf332-C231 antigen and protection from malaria, and induction of protective antibodies by sub-patent malaria infections, in Daraweesh

    DEFF Research Database (Denmark)

    Giha, Hayder A; Nasr, Amre; Iriemenam, Nnaemeka C

    2010-01-01

    The certainty of the protective role of acquired immunity in malaria is the major drive for malaria vaccine development. In this study, we measured the levels of total IgG and IgG subclasses to four candidate malaria vaccine antigens; MSP2-3D7, MSP2-FC27, AMA-1 and Pf332-C231, in plasma obtained ...

  14. HIV-specific Fc effector function early in infection predicts the development of broadly neutralizing antibodies.

    Directory of Open Access Journals (Sweden)

    Simone I Richardson

    2018-04-01

    Full Text Available While the induction of broadly neutralizing antibodies (bNAbs is a major goal of HIV vaccination strategies, there is mounting evidence to suggest that antibodies with Fc effector function also contribute to protection against HIV infection. Here we investigated Fc effector functionality of HIV-specific IgG plasma antibodies over 3 years of infection in 23 individuals, 13 of whom developed bNAbs. Antibody-dependent cellular phagocytosis (ADCP, complement deposition (ADCD, cellular cytotoxicity (ADCC and cellular trogocytosis (ADCT were detected in almost all individuals with levels of activity increasing over time. At 6 months post-infection, individuals with bNAbs had significantly higher levels of ADCD and ADCT that correlated with antibody binding to C1q and FcγRIIa respectively. In addition, antibodies from individuals with bNAbs showed more IgG subclass diversity to multiple HIV antigens which also correlated with Fc polyfunctionality. Germinal center activity represented by CXCL13 levels and expression of activation-induced cytidine deaminase (AID was found to be associated with neutralization breadth, Fc polyfunctionality and IgG subclass diversity. Overall, multivariate analysis by random forest classification was able to group bNAb individuals with 85% sensitivity and 80% specificity based on the properties of their antibody Fc early in HIV infection. Thus, the Fc effector function profile predicted the development of neutralization breadth in this cohort, suggesting that intrinsic immune factors within the germinal center provide a mechanistic link between the Fc and Fab of HIV-specific antibodies.

  15. HIV-specific Fc effector function early in infection predicts the development of broadly neutralizing antibodies.

    Science.gov (United States)

    Richardson, Simone I; Chung, Amy W; Natarajan, Harini; Mabvakure, Batsirai; Mkhize, Nonhlanhla N; Garrett, Nigel; Abdool Karim, Salim; Moore, Penny L; Ackerman, Margaret E; Alter, Galit; Morris, Lynn

    2018-04-01

    While the induction of broadly neutralizing antibodies (bNAbs) is a major goal of HIV vaccination strategies, there is mounting evidence to suggest that antibodies with Fc effector function also contribute to protection against HIV infection. Here we investigated Fc effector functionality of HIV-specific IgG plasma antibodies over 3 years of infection in 23 individuals, 13 of whom developed bNAbs. Antibody-dependent cellular phagocytosis (ADCP), complement deposition (ADCD), cellular cytotoxicity (ADCC) and cellular trogocytosis (ADCT) were detected in almost all individuals with levels of activity increasing over time. At 6 months post-infection, individuals with bNAbs had significantly higher levels of ADCD and ADCT that correlated with antibody binding to C1q and FcγRIIa respectively. In addition, antibodies from individuals with bNAbs showed more IgG subclass diversity to multiple HIV antigens which also correlated with Fc polyfunctionality. Germinal center activity represented by CXCL13 levels and expression of activation-induced cytidine deaminase (AID) was found to be associated with neutralization breadth, Fc polyfunctionality and IgG subclass diversity. Overall, multivariate analysis by random forest classification was able to group bNAb individuals with 85% sensitivity and 80% specificity based on the properties of their antibody Fc early in HIV infection. Thus, the Fc effector function profile predicted the development of neutralization breadth in this cohort, suggesting that intrinsic immune factors within the germinal center provide a mechanistic link between the Fc and Fab of HIV-specific antibodies.

  16. 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.

  17. Safety and pharmacokinetics of the Fc-modified HIV-1 human monoclonal antibody VRC01LS: A Phase 1 open-label clinical trial in healthy adults.

    Directory of Open Access Journals (Sweden)

    Martin R Gaudinski

    2018-01-01

    Full Text Available VRC01 is a human broadly neutralizing monoclonal antibody (bnMAb against the CD4-binding site of the HIV-1 envelope glycoprotein (Env that is currently being evaluated in a Phase IIb adult HIV-1 prevention efficacy trial. VRC01LS is a modified version of VRC01, designed for extended serum half-life by increased binding affinity to the neonatal Fc receptor.This Phase I dose-escalation study of VRC01LS in HIV-negative healthy adults was conducted by the Vaccine Research Center (VRC at the National Institutes of Health (NIH Clinical Center (Bethesda, MD. The age range of the study volunteers was 21-50 years; 51% of study volunteers were male and 49% were female. Primary objectives were safety and tolerability of VRC01LS intravenous (IV infusions at 5, 20, and 40 mg/kg infused once, 20 mg/kg given three times at 12-week intervals, and subcutaneous (SC delivery at 5 mg/kg delivered once, or three times at 12-week intervals. Secondary objectives were pharmacokinetics (PK, serum neutralization activity, and development of antidrug antibodies. Enrollment began on November 16, 2015, and concluded on August 23, 2017. This report describes the safety data for the first 37 volunteers who received administrations of VRC01LS. There were no serious adverse events (SAEs or dose-limiting toxicities. Mild malaise and myalgia were the most common adverse events (AEs. There were six AEs assessed as possibly related to VRC01LS administration, and all were mild in severity and resolved during the study. PK data were modeled based on the first dose of VRC01LS in the first 25 volunteers to complete their schedule of evaluations. The mean (±SD serum concentration 12 weeks after one IV administration of 20 mg/kg or 40 mg/kg were 180 ± 43 μg/mL (n = 7 and 326 ± 35 μg/mL (n = 5, respectively. The mean (±SD serum concentration 12 weeks after one IV and SC administration of 5 mg/kg were 40 ± 3 μg/mL (n = 2 and 25 ± 5 μg/mL (n = 9, respectively. Over the 5-40 mg

  18. Attenuated atherosclerotic lesions in apoe-fc gamma-chain-deficient hyperlipidemic mouse model is associated with inhibition of Th17 cells and promotion of regulatory T cells

    Science.gov (United States)

    Though the presence of antioxidized low-density lipoprotein IgG is well documented in clinical and animal studies, the role for Fc gamma Rs to the progression of atherosclerosis has not been studied in detail. In the current study, we investigated the role for activating Fc gamma R in the progressio...

  19. IgG and complement deposition and neuronal loss in cats and humans with epilepsy and voltage-gated potassium channel complex antibodies.

    Science.gov (United States)

    Klang, Andrea; Schmidt, Peter; Kneissl, Sibylle; Bagó, Zoltán; Vincent, Angela; Lang, Bethan; Moloney, Teresa; Bien, Christian G; Halász, Péter; Bauer, Jan; Pákozdy, Akos

    2014-05-01

    Voltage-gated potassium channel complex (VGKC-complex) antibody (Ab) encephalitis is a well-recognized form of limbic encephalitis in humans, usually occurring in the absence of an underlying tumor. The patients have a subacute onset of seizures, magnetic resonance imaging findings suggestive of hippocampal inflammation, and high serum titers of Abs against proteins of the VGKC-complex, particularly leucine-rich, glioma-inactivated 1 (LGI1). Most patients are diagnosed promptly and recover substantially with immunotherapies; consequently, neuropathological data are limited. We have recently shown that feline complex partial cluster seizures with orofacial involvement (FEPSO) in cats can also be associated with Abs against VGKC-complexes/LGI1. Here we examined the brains of cats with FEPSO and compared the neuropathological findings with those in a human with VGKC-complex-Ab limbic encephalitis. Similar to humans, cats with VGKC-complex-Ab and FEPSO have hippocampal lesions with only moderate T-cell infiltrates but with marked IgG infiltration and complement C9neo deposition on hippocampal neurons, associated with neuronal loss. These findings provide further evidence that FEPSO is a feline form of VGKC-complex-Ab limbic encephalitis and provide a model for increasing understanding of the human disease.

  20. Analyses of the peripheral immunome following multiple administrations of avelumab, a human IgG1 anti-PD-L1 monoclonal antibody.

    Science.gov (United States)

    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

    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 of human tumor cells, and clinical studies have demonstrated anti-tumor activity versus a range of human cancers. This study was designed to investigate the effect on immune cell subsets in the peripheral blood of cancer patients prior to and following multiple administrations of avelumab. One hundred twenty-three distinct immune cell subsets in the peripheral blood of cancer patients ( n  = 28) in a phase I trial were analyzed by flow cytometry prior to and following one, three, and nine cycles of avelumab. Changes in soluble (s) CD27 and sCD40L in plasma were also evaluated. In vitro studies were also performed to determine if avelumab would mediate ADCC of PBMC. No statistically significant changes in any of the 123 immune cell subsets analyzed were observed at any dose level, or number of doses, of avelumab. Increases in the ratio of sCD27:sCD40L were observed, suggesting potential immune activation. Controlled in vitro studies also showed lysis of tumor cells by avelumab versus no lysis of PBMC from five donors. These studies demonstrate the lack of any significant effect on multiple immune cell subsets, even those expressing PD-L1, following multiple cycles of avelumab. These results complement prior studies showing anti-tumor effects of avelumab and comparable levels of adverse events with avelumab versus other anti-PD-1/PD-L1 MAbs. These studies provide the rationale to further exploit the potential ADCC mechanism of action of avelumab as well as other human IgG1 checkpoint

  1. 99mTc human IgG radiolabelled by HYNIC. Biodistribution and scintigraphy of experimentally induced inflammatory lesions in animal model

    International Nuclear Information System (INIS)

    Karczmarczyk, U.; Markiewicz, A.; Mikolajczak, R.; Michalik, J.; Lisiak, E.; Bilski, M.; Pietrzykowski, J.

    2004-01-01

    Our goal was the efficient labelling of highly purified human gammaglobulin. This radioactive protein fraction can be used as a basic compound of radiopharmaceutical formulation for inflammation lesion diagnosis. This application was experimentally illustrated in animal models with artificially induced inflammatory lesions after turpentine oil injection into mouse leg muscle. Hydrazine nicotinamine derivative of human gammaglobulin (IgG-HYNIC) was synthesized according to Abrams method. The radionuclide: technetium 99mT c has been introduced into protein molecules by indirect method incorporation in phosphate buffer, pH 7.4, in the presence of stannous chloride as a reducing agent for sodium pertechnetate, and EDTA as a coligand. Radiochemical purity was estimated by thin layer chromatography. The stability of labelled IgG-HYNIC derivative in human serum in presence of copper, cobalt, iron and manganese salts was analyzed by HPLC method (BioSEP SEC 4000, eluent: 0.1mol/L phosphate). Inflammation lesions were induced in Balb/3 mice muscles by injection of 0.2 ml turpentine oil into the leg muscle. Five days later, inflammation lesions were visualized by hIgG-HYNIC- 99mT c injections. The tracer accumulation in tissue was evaluated by gamma camera at 1 to 24 hour intervals. Efficiency of technetium 99mT c human gammaglobulin labelling (pH 7.4, temp. 37 o C) was strictly dependant on ligand and coligand presence in the reaction mixture. Labelling of IgG molecules without any supplements resulted in very low efficiency, never exceeding the range of 5%. Presence of EDTA or hydrazine nicotinamide (HYNIC) conjugated with IgG increased radiolabelling efficiency to 50%. IgG-HYNIC derivative in EDTA presence enables us to reach value above 95% radiochemical purity. Stability of IgG-HYNIC derivative labelled with technetium 99mT c decreased rapidly in serum in time - up to 70% of initial value in 30 minutes and only 20% during further 4 hr incubation. This means that as much

  2. Rabbit IgG directed to a synthetic C-terminal peptide of the major grass pollen allergen Lol p I inhibits human basophil histamine release induced by natural Lol p I

    NARCIS (Netherlands)

    van Ree, R.; Aalberse, R. C.

    1995-01-01

    The potential role of allergen-specific IgG antibodies as 'blocking' antibodies in allergen-induced human basophil histamine release was investigated. This was studied in a model with the major grass pollen allergen Lol p I and polyclonal rabbit antisera directed against this allergen and against a

  3. A new human IgG avidity test, using mixtures of recombinant antigens (rROP1, rSAG2, rGRA6), for the diagnosis of difficult-to-identify phases of toxoplasmosis.

    Science.gov (United States)

    Drapała, Dorota; Holec-Gąsior, Lucyna; Kur, Józef; Ferra, Bartłomiej; Hiszczyńska-Sawicka, Elżbieta; Lautenbach, Dariusz

    2014-07-01

    The preliminary diagnostic utility of two mixtures of Toxoplasma gondii recombinant antigens (rROP1+rSAG2 and rROP1+rGRA6) in IgG ELISA and IgG avidity test has been evaluated. A total of 173 serum samples from patients with toxoplasmosis and seronegative people were examined. The sensitivity of IgG ELISA for rROP1+rSAG2 and rROP1+rGRA6 was 91.1% and 76.7%, respectively, while the reactivity for sera from patients where acute toxoplasmosis was suspected was higher, at 100% and 95.4%, respectively, than for people with chronic infection, at 88.2% and 70.6%. In this study a different trend in avidity maturation of IgG antibodies for two mixtures of proteins in comparison with native antigen was observed. The results suggest that a new IgG avidity test using the mixtures of recombinant antigens may be useful for the diagnosis of difficult-to-identify phases of toxoplasmosis. For this reason, selected mixtures after the additional tests on groups of sera with well-defined dates of infection could be used as a better alternative to the native antigens of the parasite in the serodiagnosis of human T. gondii infection. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Lysine conjugation properties in human IgGs studied by integrating high-resolution native mass spectrometry and bottom-up proteomics

    NARCIS (Netherlands)

    Gautier, Violette|info:eu-repo/dai/nl/372660851; Boumeester, Anja J.; Lössl, Philip|info:eu-repo/dai/nl/371559693; Heck, Albert J R|info:eu-repo/dai/nl/105189332

    2015-01-01

    Antibody-drug conjugates (ADCs) are a novel class of biopharmaceuticals several of which are now being investigated in clinical studies. In ADCs, potent cytotoxic drugs are coupled via a linker to reactive residues in IgG monoclonal antibodies. Linkage to lysine residues in the IgGs, using

  5. Activatory and Inhibitory Fcγ Receptors Augment Rituximab-mediated Internalization of CD20 Independent of Signaling via the Cytoplasmic Domain*

    Science.gov (United States)

    Vaughan, Andrew T.; Chan, Claude H. T.; Klein, Christian; Glennie, Martin J.; Beers, Stephen A.; Cragg, Mark S.

    2015-01-01

    Type I anti-CD20 mAb such as rituximab and ofatumumab engage with the inhibitory FcγR, FcγRIIb on the surface of B cells, resulting in immunoreceptor tyrosine-based inhibitory motif (ITIM) phosphorylation. Internalization of the CD20·mAb·FcγRIIb complex follows, the rate of which correlates with FcγRIIb expression. In contrast, although type II anti-CD20 mAb such as tositumomab and obinutuzumab also interact with and activate FcγRIIb, this interaction fails to augment the rate of CD20·mAb internalization, raising the question of whether ITIM phosphorylation plays any role in this process. We have assessed the molecular requirements for the internalization process and demonstrate that in contrast to internalization of IgG immune complexes, FcγRIIb-augmented internalization of rituximab-ligated CD20 occurs independently of the FcγRIIb ITIM, indicating that signaling downstream of FcγRIIb is not required. In transfected cells, activatory FcγRI, FcγRIIa, and FcγRIIIa augmented internalization of rituximab-ligated CD20 in a similar manner. However, FcγRIIa mediated a slower rate of internalization than cells expressing equivalent levels of the highly homologous FcγRIIb. The difference was maintained in cells expressing FcγRIIa and FcγRIIb lacking cytoplasmic domains and in which the transmembrane domains had been exchanged. This difference may be due to increased degradation of FcγRIIa, which traffics to lysosomes independently of rituximab. We conclude that the cytoplasmic domain of FcγR is not required for promoting internalization of rituximab-ligated CD20. Instead, we propose that FcγR provides a structural role in augmenting endocytosis that differs from that employed during the endocytosis of immune complexes. PMID:25568316

  6. High-yield production of a human monoclonal IgG by rhizosecretion in hydroponic tobacco cultures

    NARCIS (Netherlands)

    Madeira, L.M.; Szeto, T.H.; Henquet, Maurice; Raven, Nicole; Runions, John; Huddleston, Jon; Garrard, Ian; Drake, P.M.W.; Ma, Julian K.C.

    2016-01-01

    Rhizosecretion of recombinant pharmaceuticals from in vitro hydroponic transgenic plant cultures is a simple, low cost, reproducible and controllable production method. Here, we demonstrate the application and adaptation of this manufacturing platform to a human antivitronectin IgG1

  7. Multivalent Fcγ-receptor engagement by a hexameric Fc-fusion protein triggers Fcγ-receptor internalisation and modulation of Fcγ-receptor functions.

    Science.gov (United States)

    Qureshi, O S; Rowley, T F; Junker, F; Peters, S J; Crilly, S; Compson, J; Eddleston, A; Björkelund, H; Greenslade, K; Parkinson, M; Davies, N L; Griffin, R; Pither, T L; Cain, K; Christodoulou, L; Staelens, L; Ward, E; Tibbitts, J; Kiessling, A; Smith, B; Brennan, F R; Malmqvist, M; Fallah-Arani, F; Humphreys, D P

    2017-12-06

    Engagement of Fcγ-receptors triggers a range of downstream signalling events resulting in a diverse array of immune functions. As a result, blockade of Fc-mediated function is an important strategy for the control of several autoimmune and inflammatory conditions. We have generated a hexameric-Fc fusion protein (hexameric-Fc) and tested the consequences of multi-valent Fcγ-receptor engagement in in vitro and in vivo systems. In vitro engagement of hexameric-Fc with FcγRs showed complex binding interactions that altered with receptor density and triggered the internalisation and degradation of Fcγ-receptors. This caused a disruption of Fc-binding and phagocytosis. In vivo, in a mouse ITP model we observed a short half-life of hexameric-Fc but were nevertheless able to observe inhibition of platelet phagocytosis several days after hexameric-Fc dosing. In cynomolgus monkeys, we again observed a short half-life, but were able to demonstrate effective FcγR blockade. These findings demonstrate the ability of multi-valent Fc-based therapeutics to interfere with FcγR function and a potential mechanism through which they could have a sustained effect; the internalisation and degradation of FcγRs.

  8. Human tonsillar IgE biosynthesis in vitro. I. Enhancement of IgE and IgG synthesis in the presence of pokeweed mitogen by T-cell irradiation

    International Nuclear Information System (INIS)

    Ohta, K.; Manzara, T.; Harbeck, R.J.; Kirkpatrick, C.H.

    1982-01-01

    A study of the events regulating human IgE biosynthesis in vitro was undertaken with tonsillar lymphocytes. IgG synthesis was also studied to evaluate the specificity of our observations. T-cell irradiation significantly enhanced synthesis of IgE by pokeweed mitogen (PWM)-stimulated B cells from 12 of 18 donors and IgG in all 18 donors. This enhancement was the result of de novo immunoglobulin synthesis, since the amount of IgE and IgG spontaneously released from lysed and lysed-and-cultured mononuclear cells was significantly less than that detected in the cell cultures, and the augmentation was completely ablated by the treatment of the cells with cycloheximide or mitomycin C. Enhancement was also dependent on the presence of PWM; T-cell irradiation did not enhance IgE synthesis in unstimulated cultures. Moreover, this enhancement was also observed in the co-cultures of B cells and allogeneic irradiated T cells. These observations suggest that radiosensitive T cells exert a suppressive activity that contributes to regulation of human IgE and IgG synthesis and that the suppressor function as well as the helper function can overcome allogeneic disparities

  9. Discovery of Human IgGs against α-Cobratoxin for Development of Recombinant Antibody-based Antivenom

    DEFF Research Database (Denmark)

    Laustsen, Andreas Hougaard; Engmark, Mikael; Redsted Rasmussen, Arne

    , in which large mammals (typically horses) are immunized with snake venom and antiserum is derived from the animals blood. The incompatibility with the human immune system of these animal derived antivenoms leads to a range of side effects,such as serum sickness, anaphylaxis, and sometimes even death......More than 5.5 million people are bitten by venomous snakes per year on a global basis. This leads to approx. 125,000 deaths and 3 times as many amputations. Particularly Sub-Saharan Africa is affected by the problem. Current antivenoms are still being produced by a method developed in the 1890’s...

  10. 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

  11. Kinetics of N-Glycan Release from Human Immunoglobulin G (IgG) by PNGase F: All Glycans Are Not Created Equal.

    Science.gov (United States)

    Huang, Yining; Orlando, Ron

    2017-12-01

    The biologic activity of IgG molecules is modulated by its crystallizable fragment N-glycosylation, and thus, the analysis of IgG glycosylation is critical. A standard approach to analyze glycosylation of IgGs involves the release of the N-glycans by the enzyme peptide N-glycosidase F, which cleaves the linkage between the asparagine residue and innermost N-acetylglucosamine (GlcNAc) of all N-glycans except those containing a 3-linked fucose attached to the reducing terminal GlcNAc residue. The importance of obtaining complete glycan release for accurate quantitation led us to investigate the kinetics of this de-glycosylation reaction for IgG glycopeptides and to determine the effect of glycan structure and amino acid sequence on the rate of glycan release from glycopeptides of IgGs. This study revealed that the slight differences in amino acid sequences did not lead to a statistically different deglycosylation rate. However, statistically significant differences in the deglycosylation rate constants were observed between glycopeptides differing only in glycan structure ( i.e. , nonfucosylated, fucosylated, bisecting-GlcNAc, sialylated, etc .). For example, a single sialic acid residue was found to decrease the rate by a factor of 3. Similar reductions in rate were associated with the presence of a bisecting-GlcNAc. We predict the differences in release kinetics can lead to significant quantitative variations of the glycosylation study of IgGs.

  12. Altered polymorphonuclear leukocyte Fc gamma R expression contributes to decreased candicidal activity during intraabdominal sepsis

    International Nuclear Information System (INIS)

    Simms, H.H.; D'Amico, R.; Monfils, P.; Burchard, K.W.

    1991-01-01

    We investigated the effects of untreated intraabdominal sepsis on polymorphonuclear leukocyte (PMN) candicidal activity. Two groups of swine were studied. Group I (n=6) underwent sham laparotomy, group II (n=7) underwent cecal ligation and incision. Untreated intraabdominal sepsis resulted in a progressive decrease in PMN candicidal activity. Concomitant rosetting and phagocytosis assays demonstrated a decrease in both the attachment and phagocytosis of Candida albicans opsonized with both normal and septic swine serum by PMNs in group II. Iodine 125-labeled swine immunoglobulin G (IgG) and fluorescein isothioalanate (FITC)-labeled swine IgG were used to investigate Fc gamma receptor ligand interactions. Scatchard analyses demonstrated a progressive decline in both the binding affinity constant and number of IgG molecules bound per PMN. Stimulation of the oxidative burst markedly reduced 125I-labeled IgG binding in both group I and group II, with a greater decrement being seen in animals with intraabdominal sepsis. Further, in group II, PMN recycling of the Fc gamma receptor to the cell surface after generation of the oxidative burst was reduced by postoperative day 4. Binding of monoclonal antibodies to Fc gamma receptor II, but not Fc gamma receptor I/III markedly reduced intracellular candicidal activity. Immunofluorescence studies revealed a homogeneous pattern of FITC-IgG uptake by nearly all group I PMNs, whereas by postoperative day 8 a substantial number of PMNs from group II failed to internalize the FITC-IgG. These studies suggest that untreated intraabdominal sepsis reduces PMN candicidal activity and that this is due, in part, to altered PMN Fc gamma receptor ligand interactions

  13. Increase of lymphocytes with Fc receptors for IgE in patients with allergic rhinitis during the grass pollen season.

    OpenAIRE

    Spiegelberg, H L; Simon, R A

    1981-01-01

    Peripheral blood lymphocytes from 10 nonallergic donors and 7 patients suffering from seasonal allergic rhinitis and receiving desensitization therapy were analyzed by rosette assays for Fc receptors for IgE (Fc epsilon R) and IgG (Fc gamma R) before, during and after the grass pollen season. Six of seven patients had moderately elevated IgE levels (330 +/- 268 IU/ml), all had high titers of skin sensitizing antibodies to grass pollens and serum IgE antibodies as measured by radio-allergosorb...

  14. Generation of CMAHKO/GTKO/shTNFRI-Fc/HO-1 quadruple gene modified pigs.

    Science.gov (United States)

    Kim, Geon A; Lee, Eun Mi; Jin, Jun-Xue; Lee, Sanghoon; Taweechaipaisankul, Anukul; Hwang, Jong Ik; Alam, Zahid; Ahn, Curie; Lee, Byeong Chun

    2017-08-01

    As an alternative source of organs for transplantation into humans, attention has been directed to pigs due to their similarities in biological features and organ size. However, severe immune rejection has prevented successful xenotransplantation using pig organs and tissues. To overcome immune rejection, recently developed genetic engineering systems such as TALEN coupled with somatic cell nuclear transfer (SCNT) to make embryos could be used to produce pigs compatible with xenotransplantation. We used the TALEN system to target the non-Gal antigen cytidine monophosphate-N-acetylneuraminic acid hydroxylase (CMAH) gene in pigs that is naturally deleted in humans. Gal-deleted cells expressing both soluble human tumor necrosis factor receptor I IgG 1 -Fc (shTNFRI-Fc) and human hemagglutinin -tagged-human heme oxygenase-1 (hHO-1) were transfected with a TALEN target for CMAH. Cells lacking CMAH were negatively selected using N-glyconeuraminic acid (Neu5Gc)/magnetic beads and the level of Neu5Gc expression of isolated cells were analyzed by FACS and DNA sequencing. Cloned embryos using 3 different genetically modified cell clones were respectively transferred into 3 recipients, with 55.6% (5/9) becoming pregnant and three cloned pigs were produced. Successful genetic disruption of the CMAH gene was confirmed by sequencing, showing lack of expression of CMAH in tail-derived fibroblasts of the cloned piglets. Besides decreased expression of Neu5Gc in piglets produced by SCNT, antibody-mediated complement-dependent cytotoxicity assays and natural antibody binding for examining immuno-reactivity of the quadruple gene modified pigs derived from endothelial cells and fibroblasts were reduced significantly compared to those of wild type animals. We conclude that by combining the TALEN system and transgenic cells, targeting of multiple genes could be useful for generating organs for xenotransplantation. We produced miniature pigs with quadruple modified genes CMAHKO/GTKO/shTNFRI-Fc

  15. An integrated practical implementation of continuous aqueous two-phase systems for the recovery of human IgG: From the microdevice to a multistage bench-scale mixer-settler device.

    Science.gov (United States)

    Espitia-Saloma, Edith; Vâzquez-Villegas, Patricia; Rito-Palomares, Marco; Aguilar, Oscar

    2016-05-01

    Aqueous two-phase systems (ATPS) are a liquid-liquid extraction technology with clear process benefits; however, its lack of industrial embracement is still a challenge to overcome. Antibodies are a potential product to be recovered by ATPS in a commercial context. The objective of this work is to present a more integral approach of the different isolated strategies that have arisen in order to enable a practical, generic implementation of ATPS, using human immunoglobulin G (IgG) as experimental model. A microfluidic device is used for ATPS parameters preselection for product recovery. ATPS were continuously operated in a mixer-settler device in one stage, multistage and multistage with recirculation configuration. Single-stage pure IgG extraction with a polyethylene glycol (PEG) 3350-phophates ATPS within continuous operation allowed a 65% recovery. Further implementation of a multistage platform promoted a higher particle partitioning reaching a 90% recovery. The processing of IgG from a cell supernatant culture harvest in a multistage system with top phase recirculation resulted in 78% IgG recovery in bottom phase. This work conjugates three not widely spread methodologies for ATPS: microfluidics, continuous and multistage operation. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. The action of NIR (808nm) laser radiation and gold nanorods labeled with IgA and IgG human antibodies on methicillin-resistant and methicillin sensitive strains of Staphylococcus aureus

    Science.gov (United States)

    Tuchina, Elena S.; Petrov, Pavel O.; Ratto, Fulvio; Centi, Sonia; Pini, Roberto; Tuchin, Valery V.

    2015-03-01

    The effect of NIR laser radiation (808 nm) on methicillin-sensitive and methicillin resistant strains of Staphylococcus aureus incubated with gold nanorods is studied. Nanorods having length of 44 (± 4) nm and diameter of 10 (± 3) nm with the absorption maximum in the NIR (800 nm), functionalized with human immunoglobulins IgA and IgG, were synthesized and used in the studies. The killing ability up to 97% of the microorganism populations by using this nanotechnology was shown.

  17. Serologic aspects of IgG4 antibodies. II. IgG4 antibodies form small, nonprecipitating immune complexes due to functional monovalency

    NARCIS (Netherlands)

    van der Zee, J. S.; van Swieten, P.; Aalberse, R. C.

    1986-01-01

    Human IgG4 antibodies directed against phospholipase A, the P1 antigen from Dermatophagoïdes pteronyssinus extracts, and cat albumin were found unable to cross-link antigen. Previously, it was demonstrated that IgG4 antibodies, in contrast to IgG1 antibodies, did not cross-link Sepharose-bound

  18. Shared IgG Infection Signatures vs. Hemorrhage-Restricted IgA Clusters in Human Dengue: A Phenotype of Differential Class-Switch via TGFβ1

    Directory of Open Access Journals (Sweden)

    Chung-Hao Huang

    2017-12-01

    Full Text Available Phenotypic manifestations of infectious diseases are closely related to individual immune responses. Methods to extract information from patients’ own immune reactions would be of great use for both diagnosis and treatment. Dengue fever is one of the diseases that clinical aggravations could occur paradoxically after humoral immunity appears. This property makes dengue fever an excellent disease model to explore. A principal component analyses (PCAs-based framework derived from a prior vaccination study was developed. The framework was verified by successful demonstrations of known IgG signatures from a Mexico Dengue data set. Afterward the pipeline was tested upon de novo IgG and IgA libraries of Dengue patients from southern Taiwan. We discovered four infection signatures within IgG repertoires, two of which were identical to previous reports. However, it was IgA but not IgG that could differentiate hemorrhagic from non-hemorrhagic patients. IgA repertoires were found more diversified among bleeders, from whom seven signature clusters were characterized. The expressions of transforming growth factor beta 1 (TGFβ1 and accordingly mediated class-switch activity of IgA were distinct only among the PCA-segregated bleeding group. In sum, intercontinental sharing of IgG signatures in dengue fever was demonstrated via a unified working flow. Differential regulation of IgA class-switch with associated diversity expansion plus existences of hemorrhage-restricted clusters were shown. The ability of the framework to find common IgG signatures would implicate applications to infections even from unknown pathogens. The clusters within IgA repertoires could offer perspectives to other IgA-related bleeding disorders such as Henoch-Schönlein purpura or IgA nephropathy. Substantiated grounds for IgA-specific effector function via TGFβ1-mediated class-switch would be a new factor to consider for infectious diseases.

  19. Prevaccination Rotavirus Serum IgG and IgA Are Associated With Lower Immunogenicity of Live, Oral Human Rotavirus Vaccine in South African Infants.

    Science.gov (United States)

    Moon, Sung-Sil; Groome, Michelle J; Velasquez, Daniel E; Parashar, Umesh D; Jones, Stephanie; Koen, Antoinette; van Niekerk, Nadia; Jiang, Baoming; Madhi, Shabir A

    2016-01-15

    Live oral rotavirus (RV) vaccines have shown modest efficacy among children in African countries for reasons that are not completely understood. We examined the possible inhibitory effect of preexisting antirotavirus antibodies on immunogenicity of monovalent RV vaccine (RV1). Mother-infant pairs were enrolled at presentation for their routine immunization visit in Soweto, South Africa, when infants were aged 5-8 weeks. Infant serum samples were obtained before the first and second doses of RV1 and 1 month after the second dose. Maternal serum and breast milk samples were obtained prior to administration of each dose of RV1 to infants. RV-specific immunoglobulin G (IgG), IgA, and neutralizing activity in sera of infants and serum or breast milk samples of mothers were measured using enzyme-linked immunosorbent assays or a microneutralization test. Of the 107 serum pairs from infants who were seronegative for RV IgA at enrollment, we observed a strong positive association between IgG titers in pre-dose 1 sera of infants and mothers and significant negative associations between IgG titers in pre-dose 1 sera of infants and seroconversion to RV1 post-dose 1. Similarly, mothers whose infants' IgA seroconverted after RV1 had significantly lower pre-dose 1 IgG titers in sera than those whose infants did not seroconvert. High levels of preexisting serum IgG, including transplacentally acquired maternal IgG, appeared to have an inhibitory effect on the immunogenicity of RV1 among infants and may, in part, contribute to lower efficacy of RV vaccines in this and other low-income settings. Published by Oxford University Press for the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  20. Fully human IgG and IgM antibodies directed against the carcinoembryonic antigen (CEA Gold 4 epitope and designed for radioimmunotherapy (RIT of colorectal cancers

    Directory of Open Access Journals (Sweden)

    Pugnière Martine

    2004-10-01

    VG-IgM biodistribution was not possible in this mouse model in which IgM displays a very short half-life due to poly-Ig receptor expression in the liver. Conclusion Our human anti-CEA IgG2κ is a promising candidate for radioimmunotherapy in intact form, as F(ab'2 fragments, or as a bispecific antibody.

  1. Construction and expression of an anti-VEGFR2 Nanobody-Fc fusionbody in NS0 host cell.

    Science.gov (United States)

    Qasemi, Maryam; Behdani, Mahdi; Shokrgozar, Mohammad Ali; Molla-Kazemiha, Vahid; Mohseni-Kuchesfahani, Homa; Habibi-Anbouhi, Mahdi

    2016-07-01

    Angiogenesis is the formation of new blood vessels which is involved in migration, growth and differentiation of endothelial cells. This process regularly occurs during growth and development in children however, in adults is usually part of a disease process such as cancer. The vascular endothelial growth factor (VEGF) is a vital player in the vascular development and angiogenesis in physiological and pathological processes. Camelid's immune system has unique antibodies which are composed of only a heavy chain homodimer and the variable domain (VHH, Nanobody). Nanobodies are small, around 15 kDa and stable. In this study, we engineered and constructed a new Nanobody-Fc fusion protein (fusionbody) composed of an anti-VEGFR2 Nanobody and an Fc fragment of human IgG1 antibody. The recombinant vector was transfected into NS0 host cells. Stable producer clones were developed and the recombinant fusionbody was expressed and purified. Functional assay showed the anti-VEGFR2 fusionbody could bind to VEGFR2 on cell surface via VHH part and could mediate killing the targeted cells through direct cell death and complement-dependent cytotoxicity (CDC). Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Pattern of pre-existing IgG subclass responses to a panel of asexual stage malaria antigens reported during the lengthy dry season in Daraweesh, Sudan

    DEFF Research Database (Denmark)

    Nasr, A; Iriemenam, N C; Troye-Blomberg, M

    2011-01-01

    The anti-malarial IgG immune response during the lengthy and dry season in areas of low malaria transmission as in Eastern Sudan is largely unknown. In this study, ELISA was used for the measurement of pre-existing total IgG and IgG subclasses to a panel of malaria antigens, MSP2-3D7, MSP2-FC27, ...

  3. Synthesis of protected peptides from the human IgG1 hinge region on PEG support using disulfide bond synthons and alkaline or enzymatic detachment

    Czech Academy of Sciences Publication Activity Database

    Niederhafner, Petr; Šafařík, Martin; Šebestík, Jaroslav; Gut, Vladimír; Maloň, Petr; Hlaváček, Jan

    2006-01-01

    Roč. 47, č. 6 (2006), s. 1023-1025 ISSN 0040-4039 R&D Projects: GA ČR(CZ) GA203/03/1362 Institutional research plan: CEZ:AV0Z40550506 Keywords : peptide synthesis * IgG1 hinge peptide * PEG carrier Subject RIV: CC - Organic Chemistry Impact factor: 2.509, year: 2006

  4. Enhancement of retroviral infection in vitro by anti-Le(y) IgG: reversal by humanization of monoclonal mouse antibody

    DEFF Research Database (Denmark)

    Hansen, J E; Sørensen, A M; Arendrup, M

    1993-01-01

    Monoclonal mouse IgG3 antibody (ABL 364) against the carbohydrate Le(y) antigen enhanced infection in vitro with HTLV-1 and with HIV-1 when propagated in both transformed and normal lymphocytes. Enhancement was independent of complement, occurred with both lymphocytes and monocytes as target cells...

  5. Use of the Brucella IgM and IgG flow assays in the serodiagnosis of human brucellosis in an area endemic for brucellosis

    NARCIS (Netherlands)

    Irmak, Hasan; Buzgan, Turan; Evirgen, Omer; Akdeniz, Hayrettin; Demiroz, A. Pekcan; Abdoel, Theresia H.; Smits, Henk L.

    2004-01-01

    The clinical utility of two complementary tests for brucellosis, the Brucella IgM and IgG flow assays, was evaluated in a hospital in eastern Turkey. The results show that the flow assays are convenient diagnostic tests for use in endemic areas. A positive result in the flow assays was obtained in

  6. Bispecific engineered antibody domains (nanoantibodies that interact noncompetitively with an HIV-1 neutralizing epitope and FcRn.

    Directory of Open Access Journals (Sweden)

    Rui Gong

    Full Text Available Libraries based on an isolated human immunoglobulin G1 (IgG1 constant domain 2 (CH2 have been previously diversified by random mutagenesis. However, native isolated CH2 is not very stable and the generation of many mutations could lead to an increase in immunogenicity. Recently, we demonstrated that engineering an additional disulfide bond and removing seven N-terminal residues results in an engineered antibody domain (eAd (m01s with highly increased stability and enhanced binding to human neonatal Fc receptor (FcRn (Gong et al, JBC, 2009 and 2011. We and others have also previously shown that grafting of the heavy chain complementarity region 3 (CDR-H3 (H3 onto cognate positions of the variable domain leads to highly diversified libraries from which a number of binders to various antigens have been selected. However, grafting of H3s to non-cognate positions in constant domains results in additional residues at the junctions of H3s and the CH2 framework. Here we describe a new method based on multi-step PCR that allows the precise replacement of loop FG (no changes in its flanking sequences by human H3s from another library. Using this method and limited mutagenesis of loops BC and DE we generated an eAd phage-displayed library. Panning of this library against an HIV-1 gp41 MPER peptide resulted in selection of a binder, m2a1, which neutralized HIV-1 isolates from different clades with modest activity and retained the m01s capability of binding to FcRn. This result provides a proof of concept that CH2-based antigen binders that also mimic to certain extent other functions of full-size antibodies (binding to FcRn can be generated; we have previously hypothesized that such binders can be made and coined the term nanoantibodies (nAbs. Further studies in animal models and in humans will show how useful nAbs could be as therapeutics and diagnostics.

  7. DETECTION OF HUMAN ANTI-ZIKA VIRUS IgG BY ELISA USING AN ANTIGEN FROM in vitro INFECTED VERO CELLS: PRELIMINARY RESULTS

    Directory of Open Access Journals (Sweden)

    Laura Masami SUMITA

    Full Text Available SUMMARY Zika virus (ZKV infection is a huge public health problem in Brazil because of the increased incidence of microcephaly in neonates from infected mothers. Detection of specific IgG antibodies in maternal serum samples constitutes an important approach for diagnosing ZKV infection and evaluating its relationship with neonatal microcephaly. However, as there is no serological test produced in Brazil to detect IgM and IgG antibodies against ZKV, we sought to examine specific IgG in serum samples from patients or suspected mothers to detect previous infection and to test for specificity with regard to flaviviral infections occurring in the same area. Brazilian Zika virus native antigens were obtained from infected Vero cell layers or free virions in the culture medium and then used in ELISA. We tested sera from eight ZKV RNA-diagnosed infected patients (ZKVR, seven neonates with microcephaly and their mothers after delivery (MM, 140 dengue virus IgM-positive (DM and IgG (DG-positive patients, and 100 yellow fever (YF-vaccinated patients. According to the ELISA, ZKVR samples were mostly positive (7/8, and all the MM serum samples were positive for ZKV IgG (7/7. In contrast, cross-reactions for dengue or yellow fever-vaccinated patients were observed, including DM (48/95, DG (10/45 or YF (3/100 serum samples; however, these cross-reactions exhibited low antigen avidity so that 6 M urea largely removed this cross-reactivity, with only a few cross-reacting samples remaining (8/140. ELISA based on extracted virions was much more specific, with all ZKVR (8/8 and MM sera being positive for ZKV IgG (7/7 and only borderline cross-reactivity found for DM (6/95, DG (3/45 or YF (4/100-vaccinated serum samples. This technique (ELISA can identify specific IgG in ZKV-infected patients and may be helpful in diagnosing congenital infetions after maternal RNA virus clearance or in epidemiological studies.

  8. Correlation between CD16a binding and immuno effector functionality of an antigen specific immunoglobulin Fc fragment (Fcab).

    Science.gov (United States)

    Kainer, Manuela; Antes, Bernhard; Wiederkum, Susanne; Wozniak-Knopp, Gordana; Bauer, Anton; Rüker, Florian; Woisetschläger, Max

    2012-10-15

    Antigen binding immunoglobulin Fc fragments (Fcab) are generated by engineering loop regions in the CH3 domain of human IgG1 Fc. Variants of an Fcab specific for Her-2 were designed to display either enhanced (S239D:A330L:I332E) or diminished (L234A:L235A) binding affinities to the Fc receptor CD16a based on mutations described previously. The two mutant Fcab proteins demonstrated the expected modulation of CD16a binding. Interaction with recombinant or cell surface expressed Her-2 was unaffected in both mutants compared to the parental Fcab. Binding affinities for CD16a correlated with the ADCC-potencies of the Fcab variants. Additional studies indicated that the L234A:L235A variant Fcab had equivalent structural features as the unmodified Fcab since their DSC profiles were similar and antigen binding after re-folding upon partial heat denaturation had not changed. Introduction of the S239D:A330L:I332E mutations resulted in a significant reduction of the CH2 domain melting temperature, a moderate decrease of the thermal transition of the CH3 domain and lower antigen binding after thermal stress compared to the parental Fcab. We conclude that the known correlation between CD16a binding affinity and ADCC potency is also valid in Fcab proteins and that antigen specific Fcab molecules can be further engineered for fine tuning of immuno effector functions. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Chicken IgY Fc linked to Bordetella avium ompA and Taishan Pinus massoniana pollen polysaccharide adjuvant enhances macrophage function and specific immune responses

    Directory of Open Access Journals (Sweden)

    Zhu Ruiliang

    2016-11-01

    Full Text Available Fc-fusion technologies, in which immunoglobulin Fc is genetically fused to an antigenic protein, have been developed to confer antibody-like properties to proteins and peptides. Mammalian IgG Fc fusion exhibits improved antigen-induced immune responses by providing aggregates with high avidity for the IgG Fc receptor and salvaging the antigenic portion from endosomal degradation. However, whether the linked chicken IgY Fc fragment shares similar characteristics to mammalian IgG Fc remains unclear. In this study, we linked the chicken IgY Fc gene to the outer membrane protein A (ompA of Borderella avium through overlapping PCR. The fusion gene was cloned into the pPIC9 plasmid to construct the recombinant Pichia pastoris transformant expressing the ompA–Fc fusion protein. The effects of the linked Fc on macrophage vitality, activity, efficiency of antigen processing, and immune responses induced by the fused ompA were investigated. Furthermore, the effect of Taishan Pinus massoniana pollen polysaccharide (TPPPS, an immunomodulator, on chicken macrophage activation was evaluated. TPPPS was also used as an adjuvant to investigate its immunomodulatory effect on immunoresponses induced by the fused ompA–Fc in chickens. The pinocytosis, phagocytosis, secretion of nitric oxide and TNF-α, and MHC-II molecular expression of the macrophages treated with the fused ompA–Fc were significantly higher than those of the macrophages treated with ompA alone. The addition of TPPPS to the fused ompA–Fc further enhanced macrophage functions. The fused ompA–Fc elicited higher antigen-specific immune responses and protective efficacy compared with ompA alone. Moreover, the fused ompA–Fc conferred higher serum antibody titers, serum IL-2 and IL-4 concentrations, CD4+ and CD8+ T-lymphocyte counts, lymphocyte transformation rate, and protection rate compared with ompA alone. Notably, the prepared TPPPS adjuvant ompA–Fc vaccines induced high immune

  10. Mycoplasma infection of cell lines can simulate the expression of Fc receptors by binding of the carbohydrate moiety of antibodies.

    Science.gov (United States)

    Lemke, H; Krausse, R; Lorenzen, J; Havsteen, B

    1985-05-01

    During the production of Fc receptor (FcR)-bearing hybridomas it was observed with a particular monoclonal anti-sheep red blood cell antibody (anti-SRBC 1/5, IgG1) that the contamination with Mycoplasma arginini of in vitro cultured cell lines leads to an apparent FcR activity. This property did not correspond with the serological typing since other antibodies of the same isotype could not support FcR rosette formation. Another mycoplasma strain M. orale lacked this property. Analysis of the binding reaction revealed that M. arginini contains a lectin which binds the carbohydrate moiety of the anti-SRBC 1/5 antibody, i.e. anti-SRBC 1/5 synthesized under the influence of tunicamycin or deglycosylated by NaIO4 oxidation did not support rosette formation. These data suggest that binding of antibodies to certain mycoplasma strains may be a pathogenic factor during mycoplasma infections by masking the microorganisms with the host's own defense molecules. The experiments with M. arginini-infected cell lines gain immunological importance since we obtained identical results with staphylococcal protein A, as another bacteriological FcR, and cell lines expressing intrinsic membrane FcR. Although it is an open question whether the glycoconjugates are directly bound by the FcR or else by influencing the three-dimensional structure of the antibodies, it seems possible that FcR in general may be lectins.

  11. Macrophage colony stimulating factor (M-CSF) induces Fc receptor expression on macrophages

    International Nuclear Information System (INIS)

    Magee, D.M.; Wing, E.J.; Waheed, A.; Shadduck, R.K.

    1986-01-01

    M-CSF is a glycoprotein that stimulates bone marrow progenitor cells to proliferate and differentiate into macrophages (M theta). In addition, M-CSF can modulate the function of mature M theta. In this study, the authors determined the effect of M-CSF on expression of receptors for IgG (Fc receptors). Murine resident peritoneal M theta monolayers were incubated with either M-CSF, recombinant gamma interferon (IFN), or left untreated for 48 hrs. Expression of Fc receptors was assessed by microscopy using an antibody coated sheet erythrocytes (EA) rosette assay. The results indicated that M-CSF treated M theta had significantly higher numbers of bound EA (7.1 erythrocytes/M theta), than IFN M theta (4.4), or untreated M theta (2.5) (p 51 Cr labelled EA assay, CSF M theta (16,411 cpm), IFN M theta (10,887), untreated M theta (6897) (p < 0.001). Additionally, the maximal response was noted between 10 and 500 units M-CSF. Purified anti-M-CSF IgG, when included in the cultures, ablated the enhancement of EA binding, whereas normal rabbit IgG did not. These findings indicate that M-CSF is a potent inducer of Fc receptor expression on M theta and supports other data concerning the role of M-CSF as a biological response modifier

  12. Fcγ receptor expression on splenic macrophages in adult immune thrombocytopenia

    NARCIS (Netherlands)

    Audia, S; Santegoets, K; Laarhoven, A G; Vidarsson, G; Facy, O; Ortega-Deballon, P; Samson, M; Janikashvili, N; Saas, P; Bonnotte, B; Radstake, T R

    2017-01-01

    Splenic macrophages play a key role in immune thrombocytopenia (ITP) pathogenesis by clearing opsonized platelets. Fcγ receptors (FcγR) participate in this phenomenon, but their expression on splenic macrophages and their modulation by treatment have scarcely been studied in human ITP. We aimed to

  13. Rabbit IgG directed to a synthetic C-terminal peptide of the major grass pollen allergen Lol p I inhibits human basophil histamine release induced by natural Lol p I.

    Science.gov (United States)

    van Ree, R; Aalberse, R C

    1995-03-01

    The potential role of allergen-specific IgG antibodies as 'blocking' antibodies in allergen-induced human basophil histamine release was investigated. This was studied in a model with the major grass pollen allergen Lol p I and polyclonal rabbit antisera directed against this allergen and against a synthetic peptide of its C terminus. When allergen and antibodies were allowed to preincubate, Lol p I induced histamine release was inhibited up to 85% by the antiserum against Lol p I. By omitting preincubation, and thereby more closely mimicking an in vivo situation, up to 55% inhibition was realized. This indicates that allergen-specific IgG can act as 'blocking' antibody without preincubation. Immunization of rabbits with a synthetic C-terminal peptide of Lol p I resulted in antibodies reactive with natural Lol p I. Despite their 100-fold lower avidity for Lol p I (as compared with antinatural Lol p I), these antibodies had the capacity to inhibit Lol p I induced histamine release for > 90% (up to 50% without preincubation). This indicates that it is possible to block histamine release induced by a major allergen with low-avidity IgG antibodies directed against a minor proportion of the allergen (25 amino acids). IgE antibodies from the donors studied were unreactive with this synthetic peptide, indicating that for blocking activity identical epitope specificity of IgE and IgG is not essential. This opens interesting perspectives for application of synthetic peptides in immunotherapy, distinct from their effects on T cell reactivity.

  14. Immunoglobulin Fc receptors in clinical strains of Staphylococcus aureus do not confer resistance to Phagocytosis in an in vitro assay Los receptores Fc para inmunoglobulinas en cepas clínicas de Staphylococcus aureus no confieren resistencia a la fagocitosis in vitro

    Directory of Open Access Journals (Sweden)

    Benito VEGA

    1999-05-01

    Full Text Available Staphylococcus aureus binds Immunoglobulin G (IgG on its external surface due to the presence of specific receptors for the Fc domain of this immunoglobulin. This mechanism represents a kind of camouflage against phagocytic cells. In order to confirm that possibility an in vitro evaluation of the phagocytic activity of leukocytes polymorpho-nuclear (PMN against strains of Staphylococcus aureus was done, comparing 18 strains isolated from clinical samples and 16 from healthy individuals. The presence of Fc receptors was evaluated by haemagglutination (HA with erythrocytes group A after incubation of the strains with IgG anti blood group A. Phagocytosis of S. aureus was carried out by mixing live bacteria with a suspension of human PMN and incubating at 37 °C for 1 h; survivors were counted as colony forming units by plating. The strains from clinical specimens showed higher HA than those from healthy individuals (p = 0.01; but the former were killed more efficiently than the latter (80-90% and 40%, respectively. It is may be possible that S. aureus showed different behavior in vivo, where could express other virulence factors to prevent the action of phagocytes.Staphylococcus aureus liga inmunoglobulinas G (IgG a su superficie externa debido a la presencia de receptores para el dominio Fc de esas inmunoglobulinas. Este mecanismo representa una clase de camuflage contra células fagocíticas. Para confirmar tal posibilidad se realizó una evaluación in vitro de la actividad fagocítica de leucocitos polimorfonucleares (PMN contra cepas de Staphylococcus aureus, comparando 18 cepas aisladas de casos clínicos y 16 de individuos sanos. La presencia de receptores fue evaluada por hemaglutinación (HA con eritrocitos grupo A luego que las cepas fueron incubadas con IgG anti grupo sanguíneo A. La fagocitosis de S. aureus fue realizada mezclando células vivas con una suspensión de PMN e incubada a 37 °C por una hora; las bacterias sobrevivientes

  15. In vitro evaluation of the monoclonal antibody Cu-64-IgG M75 against human carbonic anhydrase IX and its in vivo imaging

    Czech Academy of Sciences Publication Activity Database

    Čepa, Adam; Ráliš, Jan; Král, Vlastimil; Paurová, M.; Kučka, Jan; Humajová, J.; Lázníček, M.; Lebeda, Ondřej

    2018-01-01

    Roč. 133, č. March (2018), s. 9-13 ISSN 0969-8043 Institutional support: RVO:61389005 ; RVO:68378050 ; RVO:61389013 Keywords : IgG M75 * immunoaffinity * imaging * monoclonal atibody * Cu-64 Subject RIV: FP - Other Medical Disciplines; CD - Macromolecular Chemistry (UMCH-V); EB - Genetics ; Molecular Biology (UMG-J) OBOR OECD: Radiology, nuclear medicine and medical imaging; Polymer science (UMCH-V); Biochemical research methods (UMG-J) Impact factor: 1.128, year: 2016

  16. Prevalence of Anti Human Herpes Virus-6 IgG and its Receptor in Acute Leukemia (Membrane Cofactor Protein: MCP, CD46)

    International Nuclear Information System (INIS)

    Assem, M.M; El-Sharkawy, N.M.; Tarek, H.; Kamel, A.M.; Gad, W.H.; El-Rouby, M.N.; Ghaleb, F.M.

    2005-01-01

    CD46 is a membrane cofactor protein, which acts as a cofactor for factor I proteolytic cleavage of C3, so it protects the cells expressing it on their surface from autologous complement attack. It has been recently described as a receptor for HHV-6. Also, it has been shown to be highly expressed on malignant cells as compared to normal cells, thus playing a major role by which these cells, either cells of haematological malignancy or cells of other body cancers, can protect themselves against complement attack so they can survive and metastasize. Patients and methods: This study has been done to detect the sero prevalence of HHV-6 among 47 Egyptian adult cases of acute leukemia using the anti-HHV-6 IgG ELISA serological technique. CD46 receptor expression and immuno phenotyping technique were performed using FCM. Twenty nine of the cases were ANLL, while 18 were ALL cases. Sixteen age- and sex-matched control cases were also studied for both anti-HHV-6 IgG and CD46 receptor expression. HHV-6 IgG antibodies were encountered in 29 (100%), 14 (77.8%) and 12 (75%) of the ANLL, ALL and the control group, cases, respectively. CD46 expression was encountered in 21 (72.4%) of the ANLL cases and in 10 (55.6%) of the ALL cases. Concordance between HHV6 sero positivity and CD46 expression was encountered in 31 cases (29 positive and 2 negative). Dis concordance was encountered in 16 cases with 14 showing HHV-6 IgG sero positivity with no CD46 expression and 2 showing the reverse. The lack of significant correlation between CD46 expression and sero positivity would exclude CD46 expression as a cause of contracting HHV-6 infection in leukemic patients

  17. The role of IgG antibodies in allergy and immunotherapy

    NARCIS (Netherlands)

    Aalberse, R.

    2011-01-01

    In specific immunotherapy (SIT), a beneficial response is associated with an increase in allergen-specific IgG(4) . This does not indicate that IgE-producing B cells have switched to IgG(4) production, because in human DNA, IgE is downstream from IgG(4) . Thus, by conventional switching, B cells

  18. Large scale purification and characterization of recombinant human autotaxin/lysophospholipase D from mammalian cells

    OpenAIRE

    Song, Yuanda; Dilger, Emily; Bell, Jessica; Barton, William A; Fang, Xianjun

    2010-01-01

    We utilized a mammalian expression system to purify and characterize autotaxin (ATX)/lysophospholipase D, an enzyme present in the blood responsible for biosynthesis of lysophosphatidic acid. The human ATX cDNA encoding amino acids 29–915 was cloned downstream of a secretion signal of CD5. At the carboxyl terminus was a thrombin cleavage site followed by the constant domain (Fc) of IgG to facilitate protein purification. The ATX-Fc fusion protein was expressed in HEK293 cells and isolated fro...

  19. HAL/S-FC compiler system specifications

    Science.gov (United States)

    1976-01-01

    This document specifies the informational interfaces within the HAL/S-FC compiler, and between the compiler and the external environment. This Compiler System Specification is for the HAL/S-FC compiler and its associated run time facilities which implement the full HAL/S language. The HAL/S-FC compiler is designed to operate stand-alone on any compatible IBM 360/370 computer and within the Software Development Laboratory (SDL) at NASA/JSC, Houston, Texas.

  20. IgG4 Cholangiopathy

    Directory of Open Access Journals (Sweden)

    Yoh Zen

    2012-01-01

    Full Text Available IgG4 cholangiopathy can involve any level of the biliary tree which exhibits sclerosing cholangitis or pseudotumorous hilar lesions. Most cases are associated with autoimmune pancreatitis, an important diagnostic clue. Without autoimmune pancreatitis, however, the diagnosis of IgG4-cholangiopathy is challenging. Indeed such cases have been treated surgically. IgG4-cholangiopathy should be diagnosed based on serological examinations including serum IgG4 concentrations, radiological features, and histological evidence of IgG4+ plasma cell infiltration. Steroid therapy is very effective even at disease relapse. A Th2-dominant immune response or the activation of regulatory T cells seems to be involved in the underlying immune reaction. It is still unknown why IgG4 levels are specifically elevated in patients with this disease. IgG4 might be secondarily overexpressed by Th2 or regulatory cytokines given the lack of evidence that IgG4 is an autoantibody.

  1. In Vitro Proliferation and Production of Cytokine and IgG by Human PBMCs Stimulated with Polysaccharide Extract from Plants Endemic to Gabon

    Directory of Open Access Journals (Sweden)

    Line Edwige Mengome

    2014-11-01

    Full Text Available Polysaccharides were extracted from seven plants endemic to Gabon to study their potential immunological activities. Peripheral blood mononuclear cell (PBMC (5 × 105 cells/mL proliferation, cytokine and immunoglobulin G (IgG assays were performed after stimulation with different concentrations of polysaccharide fractions compared with lipopolysaccharides (LPS and concanavalin A (ConA from healthy volunteers. The culture supernatants were used for cytokine and IgG detection by enzyme-linked immunosorbent assay (ELISA. The results show that pectin and hemicellulose extracts from Uvaria klainei, Petersianthus macrocarpus, Trichoscypha addonii, Aphanocalyx microphyllus, Librevillea klaineana, Neochevalierodendron stephanii and Scorodophloeus zenkeri induced production levels that were variable from one individual to another for IL-12 (3–40 pg/mL, IL-10 (6–443 pg/mL, IL-6 (7–370 pg/mL, GM-CSF (3–170 pg/mL and IFN-γ (5–80 pg/mL. Only hemicelluloses from Aphanocalyx microphyllus produce a small amount of IgG (OD = 0.034, while the proliferation of cells stimulated with these polysaccharides increased up to 318% above the proliferation of unstimulated cells. However, this proliferation of PBMCs was abolished when the pectin of some of these plants was treated with endopolygalacturonase (p < 0.05, but the trend of cytokine synthesis remained the same, both before and after enzymatic treatment or saponification. This study suggests that these polysaccharides stimulate cells in a structure-dependent manner. The rhamnogalacturonan-I (RGI fragment alone was not able to induce the proliferation of PBMC.

  2. Enhancement of retroviral infection in vitro by anti-Le(y) IgG: reversal by humanization of monoclonal mouse antibody

    DEFF Research Database (Denmark)

    Hansen, J E; Sørensen, A M; Arendrup, M

    1993-01-01

    Monoclonal mouse IgG3 antibody (ABL 364) against the carbohydrate Le(y) antigen enhanced infection in vitro with HTLV-1 and with HIV-1 when propagated in both transformed and normal lymphocytes. Enhancement was independent of complement, occurred with both lymphocytes and monocytes as target cells...... with no indication of any alternative pathway of infection, as evidenced by abrogation of enhancement by anti-CD4 MAb or soluble recombinant CD4, and also the inability of anti-Le(y) MAb to mediate HIV infection of HSB-2 cells in which HTLV-1/HIV pseudovirus infection was enhanced. While F(ab)2 fragments of ABL 364...

  3. Site-selective conjugation of an anticoagulant aptamer to recombinant albumins and maintenance of neonatal Fc receptor binding

    DEFF Research Database (Denmark)

    Schmøkel, Julie; Voldum, Anders; Tsakiridou, Georgia

    2017-01-01

    -linked aptamer to that of aptamer alone was found using an anticoagulant activity assay measuring temporal levels of activated partial thrombin. Covalent albumin-aptamer conjugation, however, substantially compromized binding to hFcRn, to 10% affinity of that of non-conjugated WT, determined by biolayer......-life, predominately facilitated by engagement with the cellular recycling neonatal Fc receptor (FcRn), and ligand transport properties of albumin promote it as an attractive candidate to improve the pharmacokinetic profile of aptamers. This study investigates the effect of Cys34 site-selective covalent attachment...... of a factor IXa anticoagulant aptamer on aptamer functionality and human FcRn (hFcRn) engagement using recombinant human albumin (rHA) of either a wild type (WT) or an engineered human FcRn high binding variant (HB). Albumin-aptamer conjugates, connected covalently through a heterobifunctional succinimidyl 4...

  4. IgG4-related disease of the biliary tract and pancreas: clinical and experimental advances.

    Science.gov (United States)

    Hubers, Lowiek M; Beuers, Ulrich

    2017-07-01

    IgG4-related disease (IgG4-RD) is an immune-mediated disease of unknown cause. It predominantly affects the biliary tract [IgG4-associated cholangitis (IAC)] and pancreas [autoimmune pancreatitis (AIP)] of mostly elderly men. Accurate diagnostic tests are lacking. Patients benefit from predniso(lo)ne treatment. However, disease relapse is often seen. This review will address pathophysiological aspects and advances in diagnostic and therapeutic strategies. The role of IgG1 and IgG4 in the pathophysiology of IgG4-RD was studied in mice which showed more intense organ damage of pancreas and salivary glands when IgG1 rather than IgG4 of patients with IgG4-RD was injected. Coadministration of IgG1+IgG4 led to dampening of IgG1-mediated injury supporting the view that IgG4 exerts immune-dampening effects. IgG4+ B-cell receptor clones identified by next-generation sequencing and the IgG4/IgG RNA ratio in human blood assessed by quantitative PCR were able to accurately distinguish IAC/AIP from primary sclerosing cholangitis or pancreatobiliary malignancies. Long-term treatment with low-dose prednisolone was safe and reduced the number of flare-ups in patients with AIP. Early diagnosis by a novel accurate and easy-to-use qPCR test may prevent life-threatening complications, unnecessary interventions and fatal course because of misdiagnosis. Prednisolone treatment remains the standard of care in patients with IgG4-RD.

  5. Immunoradiometric assay for cytomegalovirus-specific IgG antibodies

    International Nuclear Information System (INIS)

    Klapper, P.E.; Cleator, G.M.; Prinja-Wolks, D.; Morris, D.J.

    1990-01-01

    An immunoradiometric assay (radio-immunosorbent test; RIST) for the detection of IgG antibodies to human herpesvirus 4 [human cytomegalovirus (CMV)] has been developed. The technique utilizes CMV antigen passively adsorbed to a polyvinyl microtitration plate and a radiolabelled murine monoclonal anti-human IgG antibody to detect binding of human antibody to the 'solid phase' reagent. The assay was optimized, and its specifity confirmed by testing paired acute and convalescent sera from patients with acute CMV or other human herpesvirus infections. To determine the assay's sensitivity 1433 blood donor sera were examined. The RIST was more sensitive than a standard complement fixation (CFT). Use of a monoclonal anti-human IgG antibody in the RIST reduced non-specific binding to the control uninfected cell antigen such that blood donor sera could be tested in the assay using only a CMV antigen without generating an unacceptable false positive rate. (author). 23 refs.; 1 tab

  6. Engineering of Immunoglobulin Fc Heterodimers Using Yeast Surface-Displayed Combinatorial Fc Library Screening.

    Directory of Open Access Journals (Sweden)

    Hye-Ji Choi

    Full Text Available Immunoglobulin Fc heterodimers, which are useful scaffolds for the generation of bispecific antibodies, have been mostly generated through structure-based rational design methods that introduce asymmetric mutations into the CH3 homodimeric interface to favor heterodimeric Fc formation. Here, we report an approach to generate heterodimeric Fc variants through directed evolution combined with yeast surface display. We developed a combinatorial heterodimeric Fc library display system by mating two haploid yeast cell lines, one haploid cell line displayed an Fc chain library (displayed FcCH3A with mutations in one CH3 domain (CH3A on the yeast cell surface, and the other cell line secreted an Fc chain library (secreted FcCH3B with mutations in the other CH3 domain (CH3B. In the mated cells, secreted FcCH3B is displayed on the cell surface through heterodimerization with the displayed FcCH3A, the detection of which enabled us to screen the library for heterodimeric Fc variants. We constructed combinatorial heterodimeric Fc libraries with simultaneous mutations in the homodimer-favoring electrostatic interaction pairs K370-E357/S364 or D399-K392/K409 at the CH3 domain interface. High-throughput screening of the libraries using flow cytometry yielded heterodimeric Fc variants with heterodimer-favoring CH3 domain interface mutation pairs, some of them showed high heterodimerization yields (~80-90% with previously unidentified CH3 domain interface mutation pairs, such as hydrogen bonds and cation-π interactions. Our study provides a new approach for engineering Fc heterodimers that could be used to engineer other heterodimeric protein-protein interactions through directed evolution combined with yeast surface display.

  7. Fc-specific biotinylation of antibody using an engineered photoactivatable Z–Biotin and its biosensing application

    International Nuclear Information System (INIS)

    Yang, Hong-Ming; Bao, Ru-Meng; Yu, Chang-Mei; Lv, Yan-Na; Zhang, Wei-Fen; Tang, Jin-Bao

    2017-01-01

    The development of a site-specific and covalent attachment methodology is crucial for antibody–biotin conjugates to preserve the antigen-binding ability of antibodies and yield homogeneous products. In this study, an engineered photoactivatable Z-domain variant [an UV-active amino acid benzoylphenylalanine (Bpa) was genetically incorporated into the Z-domain] carrying one biotin molecule (Z_B_p_a–Biotin) was prepared by employing aminoacyl-tRNA synthetase/suppressor tRNA and Avitag/BirA techniques. The site-specific and covalent attachment of IgG–biotin conjugates, viz. photo-biotinylated IgG, was successfully achieved after UV exposure by combining the inherent Fc-binding capability of the Z-domain with the formation of covalent bond by the photo-crosslinker. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis assay showed that more than 90% of IgGs conjugated with Z_B_p_a–Biotin molecules suffered 3 h UV irradiation. Further pepsin digestion analysis confirmed that the Z_B_p_a–Biotin was conjugated to the Fc fragment of IgG without interference. We took the tumor biomarker carcinoembryoic antigen (CEA) as model to evaluate the detection efficiency of the site-specific photo-biotinylated IgG in biosensing application using surface plasmon resonance (SPR) technology. The photo-biotinylated IgG coated surface gave a limit of detection (LOD) of 2 ng mL"-"1, is 5-fold lower than that of the randomly NHS-biotinylated IgG (10 ng mL"-"1). Given that the (strept)avidin–biotin complex is extensively used in immunoassays, the proposed method for biotinylated IgG provides a powerful approach to further expand related applications. - Highlights: • A photoactivable Z_B_p_a–Biotin was fabricated by aaRS/tRNA and Avitag/BirA techniques. • A approach for Fc-specific photo-biotinylated IgG via Z_B_p_a–Biotin was proposed. • The photo-biotinylated IgG was used to fabricate an immunosensor for detecting CEA. • It gave a LOD of 2 ng mL"-"1 CEA

  8. Fc-specific biotinylation of antibody using an engineered photoactivatable Z–Biotin and its biosensing application

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hong-Ming; Bao, Ru-Meng; Yu, Chang-Mei; Lv, Yan-Na; Zhang, Wei-Fen; Tang, Jin-Bao, E-mail: tangjb@wfmc.edu.cn

    2017-01-01

    The development of a site-specific and covalent attachment methodology is crucial for antibody–biotin conjugates to preserve the antigen-binding ability of antibodies and yield homogeneous products. In this study, an engineered photoactivatable Z-domain variant [an UV-active amino acid benzoylphenylalanine (Bpa) was genetically incorporated into the Z-domain] carrying one biotin molecule (Z{sub Bpa}–Biotin) was prepared by employing aminoacyl-tRNA synthetase/suppressor tRNA and Avitag/BirA techniques. The site-specific and covalent attachment of IgG–biotin conjugates, viz. photo-biotinylated IgG, was successfully achieved after UV exposure by combining the inherent Fc-binding capability of the Z-domain with the formation of covalent bond by the photo-crosslinker. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis assay showed that more than 90% of IgGs conjugated with Z{sub Bpa}–Biotin molecules suffered 3 h UV irradiation. Further pepsin digestion analysis confirmed that the Z{sub Bpa}–Biotin was conjugated to the Fc fragment of IgG without interference. We took the tumor biomarker carcinoembryoic antigen (CEA) as model to evaluate the detection efficiency of the site-specific photo-biotinylated IgG in biosensing application using surface plasmon resonance (SPR) technology. The photo-biotinylated IgG coated surface gave a limit of detection (LOD) of 2 ng mL{sup -1}, is 5-fold lower than that of the randomly NHS-biotinylated IgG (10 ng mL{sup -1}). Given that the (strept)avidin–biotin complex is extensively used in immunoassays, the proposed method for biotinylated IgG provides a powerful approach to further expand related applications. - Highlights: • A photoactivable Z{sub Bpa}–Biotin was fabricated by aaRS/tRNA and Avitag/BirA techniques. • A approach for Fc-specific photo-biotinylated IgG via Z{sub Bpa}–Biotin was proposed. • The photo-biotinylated IgG was used to fabricate an immunosensor for detecting CEA. • It gave a LOD

  9. Increase in neutrophil Fc gamma receptor I expression following interferon gamma treatment in rheumatoid arthritis.

    Science.gov (United States)

    Goulding, N J; Knight, S M; Godolphin, J L; Guyre, P M

    1992-04-01

    The therapeutic potential of interferon gamma (IFN gamma) in a number of disease states is still being explored, but progress is hampered by the lack of a suitable measure of in vivo biological activity. To assess the in vivo biological effects of recombinant human IFN gamma (rhIFN gamma), 14 patients were studied in a randomised, prospective, double blind, placebo controlled trial of this cytokine for the treatment of rheumatoid arthritis. The levels of Fc gamma receptors on peripheral blood neutrophils were measured at baseline and after 21 days of once daily, subcutaneous injections of rhIFN gamma or placebo. An induction of neutrophil Fc gamma receptor type I (Fc gamma RI) was seen in the group of patients receiving recombinant human rhIFN gamma but not in those receiving placebo. No change in the expression of Fc gamma RII or Fc gamma RIII was detected. The amount of induction of Fc gamma RI detected on the neutrophils of patients receiving rhIFN gamma did not correlate with clinical measures of response at either 21 days or at the end of the study (24 weeks). No significant clinical responses were observed in the rhIFN gamma group at these times. These data confirm that the reported in vitro effect of IFN gamma on human neutrophil Fc receptor expression can be reproduced in vivo.

  10. Activatory and inhibitory Fcγ receptors augment rituximab-mediated internalization of CD20 independent of signaling via the cytoplasmic domain.

    Science.gov (United States)

    Vaughan, Andrew T; Chan, Claude H T; Klein, Christian; Glennie, Martin J; Beers, Stephen A; Cragg, Mark S

    2015-02-27

    Type I anti-CD20 mAb such as rituximab and ofatumumab engage with the inhibitory FcγR, FcγRIIb on the surface of B cells, resulting in immunoreceptor tyrosine-based inhibitory motif (ITIM) phosphorylation. Internalization of the CD20·mAb·FcγRIIb complex follows, the rate of which correlates with FcγRIIb expression. In contrast, although type II anti-CD20 mAb such as tositumomab and obinutuzumab also interact with and activate FcγRIIb, this interaction fails to augment the rate of CD20·mAb internalization, raising the question of whether ITIM phosphorylation plays any role in this process. We have assessed the molecular requirements for the internalization process and demonstrate that in contrast to internalization of IgG immune complexes, FcγRIIb-augmented internalization of rituximab-ligated CD20 occurs independently of the FcγRIIb ITIM, indicating that signaling downstream of FcγRIIb is not required. In transfected cells, activatory FcγRI, FcγRIIa, and FcγRIIIa augmented internalization of rituximab-ligated CD20 in a similar manner. However, FcγRIIa mediated a slower rate of internalization than cells expressing equivalent levels of the highly homologous FcγRIIb. The difference was maintained in cells expressing FcγRIIa and FcγRIIb lacking cytoplasmic domains and in which the transmembrane domains had been exchanged. This difference may be due to increased degradation of FcγRIIa, which traffics to lysosomes independently of rituximab. We conclude that the cytoplasmic domain of FcγR is not required for promoting internalization of rituximab-ligated CD20. Instead, we propose that FcγR provides a structural role in augmenting endocytosis that differs from that employed during the endocytosis of immune complexes. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Dicty_cDB: FC-AI04 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI04 (Link to dictyBase) - - - Contig-U15121-1 FC-AI04E (Li...nk to Original site) - - - - - - FC-AI04E 772 Show FC-AI04 Library FC (Link to library) Clone ID FC-AI04 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI04Q.Seq.d/ Representative seq. ID FC-AI...04E (Link to Original site) Representative DNA sequence >FC-AI04 (FC-AI04Q) /CSM/FC/FC-AI/FC-AI04Q.Seq....qvnkhqqvvtktvsd vlvphqvhnqvfphipqqmtlvnkhqpvvtktvsdvlvphqvhnqvfphtpqlkiqvylq vfqvvvvtiisai

  12. Dicty_cDB: FC-AI10 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI10 (Link to dictyBase) - - - Contig-U16270-1 FC-AI10F (Li...nk to Original site) FC-AI10F 405 - - - - - - Show FC-AI10 Library FC (Link to library) Clone ID FC-AI10 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI10Q.Seq.d/ Representative seq. ID FC-AI...10F (Link to Original site) Representative DNA sequence >FC-AI10 (FC-AI10Q) /CSM/FC/FC-AI/FC-AI10Q.Seq.... sequence RKKRKSDYTSFSTYIHKLLKQITPPTNAKSNEKGDRKFTISSKAMSVMNSFVHDIFDRIA TEASGLAKKKKRQTLHSRDIQVAVRIILTGELAXHAI

  13. Dicty_cDB: FC-AI23 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI23 (Link to dictyBase) - - - Contig-U15308-1 FC-AI23Z (Li...nk to Original site) - - FC-AI23Z 603 - - - - Show FC-AI23 Library FC (Link to library) Clone ID FC-AI23 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI23Q.Seq.d/ Representative seq. ID FC-AI...23Z (Link to Original site) Representative DNA sequence >FC-AI23 (FC-AI23Q) /CSM/FC/FC-AI/FC-AI23Q.Seq....LNTLAKKNEQVVEGEILAKQLTGVTAEELSEFKACFSHFDKDN DNKLNRLEFSSCLKSIGDELTEEQLNQVISKIDTDGNGTISFEEFIDYMVSSRKGTDSVE STKAAFKVMAEDKDFITEAQIRAAI

  14. Dicty_cDB: FC-AI05 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI05 (Link to dictyBase) - - - Contig-U15516-1 FC-AI05E (Li...nk to Original site) - - - - - - FC-AI05E 1189 Show FC-AI05 Library FC (Link to library) Clone ID FC-AI05 (L...//dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI05Q.Seq.d/ Representative seq. ID FC-AI...05E (Link to Original site) Representative DNA sequence >FC-AI05 (FC-AI05Q) /CSM/FC/FC-AI/FC-AI05Q.Seq...KIVGEASLKNKGKMSRVLAAKAALSARFD ALCEVSDTSYGIAYKGAVDRRAAAIEGREVRKSLNAVKPEKSGNVAKYDHTKSATTNTTR DVATKSSKESSIKQEKQ

  15. Dicty_cDB: FC-AI21 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI21 (Link to dictyBase) - - - Contig-U16254-1 FC-AI21Z (Li...nk to Original site) - - FC-AI21Z 696 - - - - Show FC-AI21 Library FC (Link to library) Clone ID FC-AI21 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI21Q.Seq.d/ Representative seq. ID FC-AI...21Z (Link to Original site) Representative DNA sequence >FC-AI21 (FC-AI21Q) /CSM/FC/FC-AI/FC-AI21Q.Seq....YPGYMYTDLSTIYERAGRIQGRNGSITQI PILTMPNDDITHPIPDLTGYITEGQIFIDRQINNRQIYPPINVLPSLSRLMKSAI

  16. FcγRIIb on myeloid cells rather than on B cells protects from collagen-induced arthritis.

    Science.gov (United States)

    Yilmaz-Elis, A Seda; Ramirez, Javier Martin; Asmawidjaja, Patrick; van der Kaa, Jos; Mus, Anne-Marie; Brem, Maarten D; Claassens, Jill W C; Breukel, Cor; Brouwers, Conny; Mangsbo, Sara M; Boross, Peter; Lubberts, Erik; Verbeek, J Sjef

    2014-06-15

    Extensive analysis of a variety of arthritis models in germline KO mice has revealed that all four receptors for the Fc part of IgG (FcγR) play a role in the disease process. However, their precise cell type-specific contribution is still unclear. In this study, we analyzed the specific role of the inhibiting FcγRIIb on B lymphocytes (using CD19Cre mice) and in the myeloid cell compartment (using C/EBPαCre mice) in the development of arthritis induced by immunization with either bovine or chicken collagen type II. Despite their comparable anti-mouse collagen autoantibody titers, full FcγRIIb knockout (KO), but not B cell-specific FcγRIIb KO, mice showed a significantly increased incidence and severity of disease compared with wild-type control mice when immunized with bovine collagen. When immunized with chicken collagen, disease incidence was significantly increased in pan-myeloid and full FcγRIIb KO mice, but not in B cell-specific KO mice, whereas disease severity was only significantly increased in full FcγRIIb KO mice compared with incidence and severity in wild-type control mice. We conclude that, although anti-mouse collagen autoantibodies are a prerequisite for the development of collagen-induced arthritis, their presence is insufficient for disease development. FcγRIIb on myeloid effector cells, as a modulator of the threshold for downstream Ab effector pathways, plays a dominant role in the susceptibility to collagen-induced arthritis, whereas FcγRIIb on B cells, as a regulator of Ab production, has a minor effect on disease susceptibility. Copyright © 2014 by The American Association of Immunologists, Inc.

  17. Development of a new high-affinity human antibody with antitumor activity against solid and blood malignancies.

    Science.gov (United States)

    Sioud, Mouldy; Westby, Phuong; Vasovic, Vlada; Fløisand, Yngvar; Peng, Qian

    2018-04-16

    mAbs have emerged as a promising strategy for the treatment of cancer. However, in several malignancies, no effective antitumor mAbs are yet available. Identifying therapeutic mAbs that recognize common tumor antigens could render the treatment widely applicable. Here, a human single-chain variable fragment (scFv) antibody library was sequentially affinity selected against a panel of human cancer cell lines and an antibody fragment (named MS5) that bound to solid and blood cancer cells was identified. The MS5 scFv was fused to the human IgG1 Fc domain to generate an antibody (MS5-Fc fusion) that induced antibody-dependent cellular cytotoxicity and phagocytosis of cancer cells by macrophages. In addition, the MS5-Fc antibody bound to primary leukemia cells and induced antibody-dependent cellular cytotoxicity. In the majority of analyzed cancer cells, the MS5-Fc antibody induced cell surface redistribution of the receptor complexes, but not internalization, thus maximizing the accessibility of the IgG1 Fc domain to immune effector cells. In vitro stability studies showed that the MS5-Fc antibody was stable after 6 d of incubation in human serum, retaining ∼60% of its initial intact form. After intravenous injections, the antibody localized into tumor tissues and inhibited the growth of 3 different human tumor xenografts (breast, lymphoma, and leukemia). These antitumor effects were associated with tumor infiltration by macrophages and NK cells. In the Ramos B-cell lymphoma xenograft model, the MS5-Fc antibody exhibited a comparable antitumor effect as rituximab, a chimeric anti-CD20 IgG1 mAb. These results indicate that human antibodies with pan-cancer abilities can be generated from phage display libraries, and that the engineered MS5-Fc antibody could be an attractive agent for further clinical investigation.-Sioud, M., Westby, P., Vasovic, V., Fløisand, Y., Peng, Q. Development of a new high-affinity human antibody with antitumor activity against solid and

  18. Anticomplementary Activity of Horse IgG and F(ab')2 Antivenoms

    OpenAIRE

    Squaiella-Baptistão, Carla Cristina; Marcelino, José Roberto; Ribeiro da Cunha, Luiz Eduardo; Gutiérrez, José María; Tambourgi, Denise V.

    2014-01-01

    2094-01 Embargo por política editorial Envenomation by poisonous animals is a neglected condition according to the World Health Organization (WHO). Antivenoms are included in the WHO Essential Medicines List. It has been assumed that immunoglobulin G (IgG) antivenoms could activate the complement system through Fc and induce early adverse reactions (EARs). However, data in the literature indicate that F(ab')2 fragments can also activate the complement system. Herein, we show that several b...

  19. Histopathologie der IgG4-RD

    DEFF Research Database (Denmark)

    Detlefsen, S; Klöppel, G

    2016-01-01

    infiltrate, 2) storiform fibrosis and 3) obliterative phlebitis. The diagnosis is further supported by immunohistochemical demonstration of an increased infiltration of IgG4-positive plasma cells and an elevated IgG4/IgG ratio. The morphological criteria of IgG4-RD are in most cases detectable in biopsies...

  20. Fc-specific biotinylation of antibody using an engineered photoactivatable Z-Biotin and its biosensing application.

    Science.gov (United States)

    Yang, Hong-Ming; Bao, Ru-Meng; Yu, Chang-Mei; Lv, Yan-Na; Zhang, Wei-Fen; Tang, Jin-Bao

    2017-01-01

    The development of a site-specific and covalent attachment methodology is crucial for antibody-biotin conjugates to preserve the antigen-binding ability of antibodies and yield homogeneous products. In this study, an engineered photoactivatable Z-domain variant [an UV-active amino acid benzoylphenylalanine (Bpa) was genetically incorporated into the Z-domain] carrying one biotin molecule (Z Bpa -Biotin) was prepared by employing aminoacyl-tRNA synthetase/suppressor tRNA and Avitag/BirA techniques. The site-specific and covalent attachment of IgG-biotin conjugates, viz. photo-biotinylated IgG, was successfully achieved after UV exposure by combining the inherent Fc-binding capability of the Z-domain with the formation of covalent bond by the photo-crosslinker. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis assay showed that more than 90% of IgGs conjugated with Z Bpa -Biotin molecules suffered 3 h UV irradiation. Further pepsin digestion analysis confirmed that the Z Bpa -Biotin was conjugated to the Fc fragment of IgG without interference. We took the tumor biomarker carcinoembryoic antigen (CEA) as model to evaluate the detection efficiency of the site-specific photo-biotinylated IgG in biosensing application using surface plasmon resonance (SPR) technology. The photo-biotinylated IgG coated surface gave a limit of detection (LOD) of 2 ng mL -1 , is 5-fold lower than that of the randomly NHS-biotinylated IgG (10 ng mL -1 ). Given that the (strept)avidin-biotin complex is extensively used in immunoassays, the proposed method for biotinylated IgG provides a powerful approach to further expand related applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. IgG4 autoantibodies are inhibitory in the autoimmune disease bullous pemphigoid.

    Science.gov (United States)

    Zuo, Yagang; Evangelista, Flor; Culton, Donna; Guilabert, Antonio; Lin, Lin; Li, Ning; Diaz, Luis; Liu, Zhi

    2016-09-01

    The IgG4 subclass of antibodies exhibits unique characteristics that suggest it may function in an immunoregulatory capacity. The inhibitory function of IgG4 has been well documented in allergic disease by the demonstration of IgG4 blocking antibodies, but similar functions have not been explored in autoimmune disease. Bullous pemphigoid (BP) is a subepidermal autoimmune blistering disease characterized by autoantibodies directed against BP180 and an inflammatory infiltrate including eosinophils and neutrophils. Animal models have revealed that the NC16A region within BP180 harbors the critical epitopes necessary for autoantibody mediated disease induction. BP180 NC16A-specific IgG belong to the IgG1, IgG3, and IgG4 subclasses. The purpose of this study was to determine effector functions of different IgG subclasses of NC16A-specific autoantibodies in BP. We find that IgG4 anti-NC16A autoantibodies inhibit the binding of IgG1 and IgG3 autoantibodies to the NC16A region. Moreover, IgG4 anti-NC16A blocks IgG1 and IgG3 induced complement fixation, neutrophil infiltration, and blister formation clinically and histologically in a dose-dependent manner following passive transfer to humanized BP180-NC16A mice. These findings highlight the inhibitory role of IgG4 in autoimmune disease and have important implications for the treatment of BP as well as other antibody mediated inflammatory and autoimmune diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. IgG4-Related Tubulointerstitial Nephritis.

    Science.gov (United States)

    Zhang, Pingchuan; Cornell, Lynn D

    2017-03-01

    Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a fibroinflammatory disorder that can involve nearly any organ. The disorder has increasingly become known as a distinct clinical entity during the last decade. IgG4-related tubulointerstitial nephritis (IgG4-TIN) is the most common manifestation of IgG4-RD in the kidney. Many patients with IgG4-TIN are diagnosed after IgG4-RD has been recognized in other organ systems, but the kidney may also be the first or only site involved. The presenting clinical features of IgG4-TIN are most commonly kidney insufficiency, kidney mass lesion(s), or both. On biopsy, IgG4-TIN shows a dense lymphoplasmacytic infiltrate, increased IgG4+ plasma cells, storiform fibrosis, and often tubular basement membrane immune complex deposits. Elevation of serum IgG4 often accompanies IgG4-RD; however, it is not specific in reaching the diagnosis. Like IgG4-RD in other organs, IgG4-TIN characteristically responds promptly to steroids, although there is a high relapse rate on discontinuation of immunosuppression. The pathogenesis of IgG4-RD is not understood. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  3. Fc-receptors and surface immunoglobulins in cells of the hairy cell leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Rieber, E P; Linke, R P; Riethmueller, G [Tuebingen Univ. (Germany, F.R.). Abt. fuer Experimentelle Chirurgie und Immunologie; Heyden, H.W. von; Waller, H D [Tuebingen Univ. (Germany, F.R.). Abt. Innere Medizin 2

    1976-01-01

    Using /sup 125/I-labelled aggregated IgG in a quantitative assay a strong expression of Fc-receptors was found on the leukemic cells of a patient with hairy cell leukemia. The Fc-receptor activity on these cells was much higher than that on monocytes and B-lymphocytes from normal blood. Surface immunoglobulins were detected by radioautography using radioactively labelled (Fab')/sub 2/-fragments of monospecific antibodies directed against immunoglobulin heavy chains. Prior to radioautography the cells were stained for the tartrate resistant acid phosphatase. It is found that all cells containing this enzyme bore delta-chains on their surface. On more than 90% of these cells a simultaneous expression of ..mu..-chains was detected. ..gamma..-chains could only be demonstrated on cells which were negative for the tartrate resistant acid phosphatase; part of these cells, however, were hairy cells by morphological criteria.

  4. Fc-receptors and surface immunoglobulins in cells of the hairy cell leukemia

    International Nuclear Information System (INIS)

    Rieber, E.P.; Linke, R.P.; Riethmueller, G.; Heyden, H.W. von; Waller, H.D.

    1976-01-01

    Using 125 I-labelled aggregated IgG in a quantitative assay a strong expression of Fc-receptors was found on the leukemic cells of a patient with hairy cell leukemia. The Fc-receptor activity on these cells was much higher than that on monocytes and B-lymphocytes from normal blood. Surface immunoglobulins were detected by radioautography using radioactively labelled (Fab') 2 -fragments of monospecific antibodies directed against immunoglobulin heavy chains. Prior to radioautography the cells were stained for the tartrate resistant acid phosphatase. It is found that all cells containing this enzyme bore delta-chains on their surface. On more than 90% of these cells a simultaneous expression of μ-chains was detected. γ-chains could only be demonstrated on cells which were negative for the tartrate resistant acid phosphatase; part of these cells, however, were hairy cells by morphological criteria. (orig.) [de

  5. Pathogenicity of IgG in patients with IgG4-related disease.

    Science.gov (United States)

    Shiokawa, Masahiro; Kodama, Yuzo; Kuriyama, Katsutoshi; Yoshimura, Kenichi; Tomono, Teruko; Morita, Toshihiro; Kakiuchi, Nobuyuki; Matsumori, Tomoaki; Mima, Atsushi; Nishikawa, Yoshihiro; Ueda, Tatsuki; Tsuda, Motoyuki; Yamauchi, Yuki; Minami, Ryuki; Sakuma, Yojiro; Ota, Yuji; Maruno, Takahisa; Kurita, Akira; Sawai, Yugo; Tsuji, Yoshihisa; Uza, Norimitsu; Matsumura, Kazuyoshi; Watanabe, Tomohiro; Notohara, Kenji; Tsuruyama, Tatsuaki; Seno, Hiroshi; Chiba, Tsutomu

    2016-08-01

    IgG4-related disease (IgG4-RD) is a systemic disease characterised by elevated serum IgG4 and IgG4-positive lymphoplasmacytic infiltration in the affected tissues. The pathogenic role of IgGs, including IgG4, in patients with IgG4-RD, however, is unknown. We examined the pathogenic activity of circulating IgGs in patients with IgG4-RD by injecting their IgGs into neonatal male Balb/c mice. Binding of patient IgGs to pancreatic tissue was also analysed in an ex vivo mouse organ culture model and in tissue samples from patients with autoimmune pancreatitis (AIP). Subcutaneous injection of patient IgG, but not control IgG, resulted in pancreatic and salivary gland injuries. Pancreatic injury was also induced by injecting patient IgG1 or IgG4, with more destructive changes induced by IgG1 than by IgG4. The potent pathogenic activity of patient IgG1 was significantly inhibited by simultaneous injection of patient IgG4. Binding of patient IgG, especially IgG1 and IgG4, to pancreatic tissue was confirmed in both the mouse model and AIP tissue samples. IgG1 and IgG4 from patients with IgG4-RD have pathogenic activities through binding affected tissues in neonatal mice. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  6. Association of FcγRIIa R131H polymorphism with idiopathic pulmonary fibrosis severity and progression

    Directory of Open Access Journals (Sweden)

    Hirani Nikhil

    2010-10-01

    Full Text Available Abstract Background A significant genetic component has been described for idiopathic pulmonary fibrosis (IPF. The R131H (rs1801274 polymorphism of the IgG receptor FcγRIIa determines receptor affinity for IgG subclasses and is associated with several chronic inflammatory diseases. We investigated whether this polymorphism is associated with IPF susceptibility or progression. Methods In a case-control study, we compared the distribution of FcγRIIa R131H genotypes in 142 patients with IPF and in 218 controls using allele-specific PCR amplification. Results No differences in the frequency of FcγRIIa genotypes were evident between IPF patients and control subjects. However, significantly impaired pulmonary function at diagnosis was observed in HH compared to RR homozygotes, with evidence of more severe restriction (reduced forced vital capacity (FVC and lower diffusing capacity for carbon monoxide (DLCO. Similarly, increased frequency of the H131 allele was observed in patients with severe disease (DLCO 10% drop in FVC and/or > 15% fall in DLCO at 12 months after baseline (0.48 vs. 0.33; p = 0.023. Conclusions These findings support an association between the FcγRIIa R131H polymorphism and IPF severity and progression, supporting the involvement of immunological mechanisms in IPF pathogenesis.

  7. 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.

  8. Dicty_cDB: FC-BR23 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-BR23 (Link to dictyBase) - - - Contig-U15008-1 FC-BR23Z (Li...nk to Original site) - - FC-BR23Z 641 - - - - Show FC-BR23 Library FC (Link to library) Clone ID FC-BR23 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-BR/FC-BR23Q.Seq.d/ Representative seq. ID FC-BR2...3Z (Link to Original site) Representative DNA sequence >FC-BR23 (FC-BR23Q) /CSM/FC/FC-BR/FC-BR23Q.Seq....9 0.0 SLA211 (SLA211Q) /CSM/SL/SLA2-A/SLA211Q.Seq.d/ 1029 0.0 FC-BR23 (FC-BR23Q) /CSM/FC/FC-BR/FC-BR2

  9. Dicty_cDB: FC-BS11 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-BS11 (Link to dictyBase) - - - Contig-U16517-1 FC-BS11Z (Li...nk to Original site) - - FC-BS11Z 683 - - - - Show FC-BS11 Library FC (Link to library) Clone ID FC-BS11 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-BS/FC-BS11Q.Seq.d/ Representative seq. ID FC-BS...11Z (Link to Original site) Representative DNA sequence >FC-BS11 (FC-BS11Q) /CSM/FC/FC-BS/FC-BS11Q.Seq....s producing significant alignments: (bits) Value FC-BS11 (FC-BS11Q) /CSM/FC/FC-BS/FC-BS

  10. Dicty_cDB: FC-BS09 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-BS09 (Link to dictyBase) - - - Contig-U16215-1 FC-BS09Z (Li...nk to Original site) - - FC-BS09Z 626 - - - - Show FC-BS09 Library FC (Link to library) Clone ID FC-BS09 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-BS/FC-BS09Q.Seq.d/ Representative seq. ID FC-BS...09Z (Link to Original site) Representative DNA sequence >FC-BS09 (FC-BS09Q) /CSM/FC/FC-BS/FC-BS09Q.Seq....ignments: (bits) Value SSF360 (SSF360Q) /CSM/SS/SSF3-C/SSF360Q.Seq.d/ 854 0.0 FC-BS09 (FC-BS09Q) /CSM/FC/FC-BS/FC-BS

  11. Dicty_cDB: FC-BS10 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-BS10 (Link to dictyBase) - - - Contig-U16283-1 FC-BS10Z (Li...nk to Original site) - - FC-BS10Z 720 - - - - Show FC-BS10 Library FC (Link to library) Clone ID FC-BS10 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-BS/FC-BS10Q.Seq.d/ Representative seq. ID FC-BS...10Z (Link to Original site) Representative DNA sequence >FC-BS10 (FC-BS10Q) /CSM/FC/FC-BS/FC-BS10Q.Seq....E Sequences producing significant alignments: (bits) Value FC-BS10 (FC-BS10Q) /CSM/FC/FC-BS/FC-BS10Q.Seq.d/

  12. Dicty_cDB: FC-BS21 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-BS21 (Link to dictyBase) - - - Contig-U15764-1 FC-BS21Z (Li...nk to Original site) - - FC-BS21Z 723 - - - - Show FC-BS21 Library FC (Link to library) Clone ID FC-BS21 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-BS/FC-BS21Q.Seq.d/ Representative seq. ID FC-BS...21Z (Link to Original site) Representative DNA sequence >FC-BS21 (FC-BS21Q) /CSM/FC/FC-BS/FC-BS21Q.Seq.... Score E Sequences producing significant alignments: (bits) Value FC-BS21 (FC-BS21Q) /CSM/FC/FC-BS/FC-BS21Q.

  13. Dicty_cDB: FC-BS19 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-BS19 (Link to dictyBase) - - - Contig-U16583-1 FC-BS19E (Li...nk to Original site) - - - - - - FC-BS19E 604 Show FC-BS19 Library FC (Link to library) Clone ID FC-BS19 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-BS/FC-BS19Q.Seq.d/ Representative seq. ID FC-BS...19E (Link to Original site) Representative DNA sequence >FC-BS19 (FC-BS19Q) /CSM/FC/FC-BS/FC-BS19Q.Seq....E Sequences producing significant alignments: (bits) Value FC-BS19 (FC-BS19Q) /CSM/FC/FC-BS/FC-BS19Q.Seq.d/

  14. Dicty_cDB: FC-AI01 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI01 (Link to dictyBase) - - - Contig-U15592-1 FC-AI01E (Li...nk to Original site) - - - - - - FC-AI01E 307 Show FC-AI01 Library FC (Link to library) Clone ID FC-AI01 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI01Q.Seq.d/ Representative seq. ID FC-AI...01E (Link to Original site) Representative DNA sequence >FC-AI01 (FC-AI01Q) /CSM/FC/FC-AI/FC-AI01Q.Seq....uences producing significant alignments: (bits) Value FC-AI01 (FC-AI01Q) /CSM/FC/FC-AI/FC-AI01Q.Seq.d/ 68 8e

  15. Dicty_cDB: FC-AI13 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI13 (Link to dictyBase) - - - Contig-U16263-1 FC-AI13F (Li...nk to Original site) FC-AI13F 507 - - - - - - Show FC-AI13 Library FC (Link to library) Clone ID FC-AI13 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI13Q.Seq.d/ Representative seq. ID FC-AI...13F (Link to Original site) Representative DNA sequence >FC-AI13 (FC-AI13Q) /CSM/FC/FC-AI/FC-AI13Q.Seq....nificant alignments: (bits) Value FC-AI13 (FC-AI13Q) /CSM/FC/FC-AI/FC-AI13Q.Seq.d/ 963 0.0 VSA730 (VSA730Q)

  16. Downmodulation of Vaccine-Induced Immunity and Protection against the Intracellular Bacterium Francisella tularensis by the Inhibitory Receptor FcγRIIB

    Directory of Open Access Journals (Sweden)

    Brian J. Franz

    2015-01-01

    Full Text Available Fc gamma receptor IIB (FcγRIIB is the only Fc gamma receptor (FcγR which negatively regulates the immune response, when engaged by antigen- (Ag- antibody (Ab complexes. Thus, the generation of Ag-specific IgG in response to infection or immunization has the potential to downmodulate immune protection against infection. Therefore, we sought to determine the impact of FcγRIIB on immune protection against Francisella tularensis (Ft, a Category A biothreat agent. We utilized inactivated Ft (iFt as an immunogen. Naïve and iFt-immunized FcγRIIB knockout (KO or wildtype (WT mice were challenged with Ft-live vaccine strain (LVS. While no significant difference in survival between naïve FcγRIIB KO versus WT mice was observed, iFt-immunized FcγRIIB KO mice were significantly better protected than iFt-immunized WT mice. Ft-specific IgA in serum and bronchial alveolar lavage, as well as IFN-γ, IL-10, and TNF-α production by splenocytes harvested from iFt-immunized FcγRIIB KO, were also significantly elevated. In addition, iFt-immunized FcγRIIB KO mice exhibited a reduction in proinflammatory cytokine levels in vivo at 5 days after challenge, which correlates with increased survival following Ft-LVS challenge in published studies. Thus, these studies demonstrate for the first time the ability of FcγRIIB to regulate vaccine-induced IgA production and downmodulate immunity and protection. The immune mechanisms behind the above observations and their potential impact on vaccine development are discussed.

  17. IgG and IgG subclasses antibody responses to rK39 in Leishmania donovani infections

    International Nuclear Information System (INIS)

    Daifalla, N.S.; El Hassan, A.M.

    1998-01-01

    Leishmania donovani infection cause a wide spectrum of human diseases ranging from self-healing subclinical infections to severe visceral leishmaniasis, post kal-azar dermal leishmaiasis, and mucosal leishmaiasis. The infection associated with high levels of anti-leishmania antibodies which offer a potential parameter for the serological diagnosis of L. donovani infection replacing the invasive parasitological methods. rK39, a cloned antigen of L. chagasis was reported to have high levels of anti-leishmania antibodies in Sudanese and American visceral leishmaniasis patients. In an assessment of rK39-ELISA in detecting L. donovani infection we found that the antigen detected visceral leishmaniasis, post kala-azar dermal leishmaniasis, and mucosal leismaniasis with the sensitives of 96.6%, 95.91% and 90.91% respectively. The test has the specificity of 96.7%. Further investigation of 25 visceral leishmaniasis patients showed elevated anti-rK39 antibody responses of IgG subclasses with IgG1 and IgG3 significantly higher than IgG4. igG3 showed the highest sensitivity (84.00%) whereas IgG1 showed the highest sensitivity (100%). The dynamics of the serological reactivity to rK39 in l.donovani infections will be discussed in relation to exposure, infection, cure and relapse.(Author)

  18. Close-up of the alpha-1,3-Gal epitope as defined by a monoclonal chimeric IgE and human serum using saturation transfer difference (STD) NMR

    DEFF Research Database (Denmark)

    Plum, Melanie; Michel, Yvonne; Wallach, Katharina

    2011-01-01

    of an alpha-Gal-specific murine IgM antibody was employed to construct chimeric IgE and IgG antibodies. Reactivity and specificity of the resulting antibodies were assessed by means of ELISA and receptor binding studies. Using defined carbohydrates, interaction of the IgE and human serum was assessed...... by mediator release assays, surface plasmon resonance (SPR) and STD NMR analyses. The alpha-Gal-specific chimeric IgE and IgG antibodies were proven functional regarding interaction with antigen and Fc receptors. SPR measurements demonstrated affinities in the micromolar range. In contrast to a reference...

  19. Reproduction of the FC/DFC units in nucleoli.

    Science.gov (United States)

    Smirnov, Evgeny; Hornáček, Matúš; Kováčik, Lubomír; Mazel, Tomáš; Schröfel, Adam; Svidenská, Silvie; Skalníková, Magdalena; Bartová, Eva; Cmarko, Dušan; Raška, Ivan

    2016-04-25

    The essential structural components of the nucleoli, Fibrillar Centers (FC) and Dense Fibrillar Components (DFC), together compose FC/DFC units, loci of rDNA transcription and early RNA processing. In the present study we followed cell cycle related changes of these units in 2 human sarcoma derived cell lines with stable expression of RFP-PCNA (the sliding clamp protein) and GFP-RPA43 (a subunit of RNA polymerase I, pol I) or GFP-fibrillarin. Correlative light and electron microscopy analysis showed that the pol I and fibrillarin positive nucleolar beads correspond to individual FC/DFC units. In vivo observations showed that at early S phase, when transcriptionally active ribosomal genes were replicated, the number of the units in each cell increased by 60-80%. During that period the units transiently lost pol I, but not fibrillarin. Then, until the end of interphase, number of the units did not change, and their duplication was completed only after the cell division, by mid G1 phase. This peculiar mode of reproduction suggests that a considerable subset of ribosomal genes remain transcriptionally silent from mid S phase to mitosis, but become again active in the postmitotic daughter cells.

  20. IgG4-related disease

    DEFF Research Database (Denmark)

    Detlefsen, Sönke; Klöppel, Günter

    2018-01-01

    disease (IgG4-RD). The histologic key findings are lymphoplasmacytic infiltration rich in IgG4-positive plasma cells combined with storiform fibrosis and obliterative phlebitis. Among the organs mainly affected by IgG4-RD are the pancreas and the extrahepatic bile ducts. The pancreatic and biliary...... alterations have been described under the terms autoimmune pancreatitis (AIP) and sclerosing cholangitis, respectively. These diseases are currently more precisely called IgG4-related pancreatitis (or type 1 AIP to distinguish it from type 2 AIP that is unrelated to IgG4-RD) and IgG4-related sclerosing...... cholangitis (IgG4-related SC). Clinically and grossly, both diseases commonly imitate pancreatic and biliary adenocarcinoma, tumors that are well known for their dismal prognosis. As IgG4-RD responds to steroid treatment, making a resection of a suspected tumor unnecessary, a biopsy is often required...

  1. Role of activatory Fc gamma RI and Fc gamma RIII and inhibitory Fc gamma RII in inflammation and cartilage destruction during experimental antigen-induced arthritis.

    NARCIS (Netherlands)

    Lent, P.L.E.M. van; Nabbe, K.C.A.M.; Blom, A.B.; Holthuysen, A.E.M.; Sloetjes, A.W.; Putte, L.B.A. van de; Verbeek, S.; Berg, W.B. van den

    2001-01-01

    IgG-containing immune complexes, which are found in most RA joints, communicate with hematopoietic cells using three classes of Fc receptors(Fc gamma RI, -II, -III). In a previous study we found that if a chronic T-cell-mediated antigen-induced arthritis (AIA) was elicited in knee joints of FcR

  2. IgG4 breaking the rules

    NARCIS (Netherlands)

    Aalberse, Rob C.; Schuurman, Janine

    2002-01-01

    Immunoglobulin G4 (IgG4) antibodies have been known for some time to be functionally monovalent. Recently, the structural basis for this monovalency has been elucidated: the in vivo exchange of IgG half-molecules (one H-plus one L-chain) among IgG4. This process results in bispecific antibodies that

  3. Hematopoietic properties of granulocyte colony-stimulating factor/immunoglobulin (G-CSF/IgG-Fc fusion proteins in normal and neutropenic rodents.

    Directory of Open Access Journals (Sweden)

    George N Cox

    Full Text Available Previously we showed that granulocyte colony-stimulating factor (G-CSF in vitro bioactivity is preserved when the protein is joined via a flexible 7 amino acid linker to an immunoglobulin-1 (IgG1-Fc domain and that the G-CSF/IgG1-Fc fusion protein possessed a longer circulating half-life and improved hematopoietic properties compared to G-CSF in normal rats. We have extended this analysis by comparing the relative hematopoietic potencies of G-CSF/IgG1-Fc to G-CSF in normal mice and to G-CSF and polyethylene glycol (PEG -modified G-CSF in neutropenic rats. Mice were treated for 5 days using different doses and dosing regimens of G-CSF/IgG1-Fc or G-CSF and circulating neutrophil levels in the animals measured on Day 6. G-CSF/IgG1-Fc stimulated greater increases in blood neutrophils than comparable doses of G-CSF when administered using daily, every other day or every third day dosing regimens. In rats made neutropenic with cyclophosphamide, G-CSF/IgG1-Fc accelerated recovery of blood neutrophils to normal levels (from Day 9 to Day 5 when administered as 5 daily injections or as a single injection on Day 1. By contrast, G-CSF accelerated neutrophil recovery when administered as 5 daily injections, but not when administered as a single injection. G-CSF/IgG1-Fc was as effective as PEG-G-CSF at accelerating neutrophil recovery following a single injection in neutropenic rats. G-CSF/IgG1-Fc and G-CSF/IgG4-Fc fusion proteins in which the 7 amino acid linker was deleted also were effective at accelerating neutrophil recovery following a single injection in neutropenic rats. These studies confirm the enhanced in vivo hematopoietic properties of G-CSF/IgG-Fc fusion proteins.

  4. Revisiting Field Capacity (FC: variation of definition of FC and its estimation from pedotransfer functions

    Directory of Open Access Journals (Sweden)

    Theophilo Benedicto Ottoni Filho

    2014-12-01

    Full Text Available Taking into account the nature of the hydrological processes involved in in situ measurement of Field Capacity (FC, this study proposes a variation of the definition of FC aiming not only at minimizing the inadequacies of its determination, but also at maintaining its original, practical meaning. Analysis of FC data for 22 Brazilian soils and additional FC data from the literature, all measured according to the proposed definition, which is based on a 48-h drainage time after infiltration by shallow ponding, indicates a weak dependency on the amount of infiltrated water, antecedent moisture level, soil morphology, and the level of the groundwater table, but a strong dependency on basic soil properties. The dependence on basic soil properties allowed determination of FC of the 22 soil profiles by pedotransfer functions (PTFs using the input variables usually adopted in prediction of soil water retention. Among the input variables, soil moisture content θ (6 kPa had the greatest impact. Indeed, a linear PTF based only on it resulted in an FC with a root mean squared residue less than 0.04 m³ m-3 for most soils individually. Such a PTF proved to be a better FC predictor than the traditional method of using moisture content at an arbitrary suction. Our FC data were compatible with an equivalent and broader USA database found in the literature, mainly for medium-texture soil samples. One reason for differences between FCs of the two data sets of fine-textured soils is due to their different drainage times. Thus, a standardized procedure for in situ determination of FC is recommended.

  5. Anti-pituitary antibodies against corticotrophs in IgG4-related hypophysitis.

    Science.gov (United States)

    Iwata, Naoko; Iwama, Shintaro; Sugimura, Yoshihisa; Yasuda, Yoshinori; Nakashima, Kohtaro; Takeuchi, Seiji; Hagiwara, Daisuke; Ito, Yoshihiro; Suga, Hidetaka; Goto, Motomitsu; Banno, Ryoichi; Caturegli, Patrizio; Koike, Teruhiko; Oshida, Yoshiharu; Arima, Hiroshi

    2017-06-01

    IgG4-related disease is a systemic inflammatory disease characterized by infiltration of IgG4-positive plasma cells into multiple organs, including the pituitary gland. Autoimmunity is thought to be involved in the pathogenesis of IgG4-related disease. The diagnosis of IgG4-related hypophysitis (IgG4-RH) is difficult because its clinical features, such as pituitary swelling and hypopituitarism, are similar to those of other pituitary diseases, including lymphocytic hypophysitis and sellar/suprasellar tumors. The presence and significance of anti-pituitary antibodies (APA) in IgG4-RH is unclear. In this case-control study, we used single indirect immunofluorescence on human pituitary substrates to assess the prevalence of serum APA in 17 patients with IgG4-RH, 8 control patients with other pituitary diseases (lymphocytic infundibulo-neurohypophysitis, 3; craniopharyngioma, 2; germinoma, 3), and 9 healthy subjects. We further analyzed the endocrine cells targeted by the antibodies using double indirect immunofluorescence. APA were found in 5 of 17 patients with IgG4-RH (29%), and in none of the pituitary controls or healthy subjects. The endocrine cells targeted by the antibodies in the 5 IgG4-RH cases were exclusively corticotrophs. Antibodies were of the IgG1 subclass, rather than IgG4, in all 5 cases, suggesting that IgG4 is not directly involved in the pathogenesis. Finally, antibodies recognized pro-opiomelanocortin in 2 of the cases. Our study suggests that autoimmunity is involved in the pathogenesis of IgG4-RH and that corticotrophs are the main antigenic target, highlighting a possible new diagnostic marker for this condition.

  6. Prevalence of IgG antibodies to human parvovirus B19 in haemophilia children treated with recombinant factor (F)VIII only or with at least one plasma-derived FVIII or FIX concentrate: results from the French haemophilia cohort.

    Science.gov (United States)

    Gaboulaud, Valérie; Parquet, Armelle; Tahiri, Cedric; Claeyssens, Ségolène; Potard, Valérie; Faradji, Albert; Peynet, Jocelyne; Costagliola, Dominique

    2002-02-01

    Human parvovirus B19 (B19) has been transmitted by some brands of virally attenuated plasma-derived factor VIII (FVIII) or IX (FIX) concentrates. To quantify the differences of human parvovirus B19 risk transmission between albumin-stabilized recombinant factor and plasma-derived factor, we studied the prevalence of IgG antibodies to B19 (anti-B19) in 193 haemophiliac children between 1 and 6-years of age who had previously been treated with albumin-stabilized recombinant FVIII only (n = 104), and in children previously treated with solvent/detergent high-purity non-immunopurified and non-nanofiltered FVIII or IX concentrates (n = 89). Association between the prevalence of anti-B19 and the treatment group was analysed using multivariate logistic regression. Age, severity and type of haemophilia, number of cumulative days of exposure to factor VIII or IX, previous history of red blood cells or plasma transfusion were considered as potential confounding variables. A higher prevalence of anti-B19 was found in children previously treated with solvent/detergent high-purity non-immunopurified and non-nanofiltered FVIII or IX concentrates than in children treated with albumin- stabilized recombinant FVIII only (OR: 22.3; CI: 7.9-62.8), independently of the other factors studied.

  7. APC targeting enhances immunogenicity of a novel multistage Fc-fusion tuberculosis vaccine in mice.

    Science.gov (United States)

    Soleimanpour, Saman; Farsiani, Hadi; Mosavat, Arman; Ghazvini, Kiarash; Eydgahi, Mohammad Reza Akbari; Sankian, Mojtaba; Sadeghian, Hamid; Meshkat, Zahra; Rezaee, Seyed Abdolrahim

    2015-12-01

    Numerous studies have demonstrated that targeting immunogens to FcγR on antigen-presenting cells (APCs) can selectively uptake and increase cellular immunity in vitro and in vivo. Therefore, the present study was conducted to evaluate immunogenicity of a novel multistage tuberculosis vaccine, a combination of an early and a dormant immunogenic protein, ESAT6 and HspX, fused to Fcγ2a fragment of mouse IgG2a to target all forms of tuberculosis. Codon-optimized genes consisting of ESAT6, a linker, and HspX fused either to mouse Fcγ2a (ESAT6:HspX:mFcγ2a) or 6× His-tag (ESAT6:HspX:His) were synthesized. The resulting proteins were then produced in Pichia pastoris. The fusion proteins were separately emulsified in dimethyldioctadecylammonium bromide(DDA)-trehalose-6,6-dibehenate(TDB) adjuvant, and their immunogenicity with and without bacille Calmette-Guérin (BCG) was assessed in C57BL/6 mice. Th1, Th2, Th17, and T-reg cytokine patterns were evaluated using the ELISA method. Both multistage vaccines induced very strong IL-12 and IFN-γ secretion from splenic cells; the Fc-tagged subunit vaccine induced a more effective Th1 immune response (IFN-γ, 910 pg/mL, and IL-12, 854 pg/mL) with a very low increase in IL-17 (∼0.1 pg/mL) and IL-4 (37 pg/mL) and a mild increase in TGF-β (543 pg/mL) compared to the BCG or ESAT6:HspX:His primed and boosted groups. The production of IFN-γ to ESAT6:HspX:Fcγ2a was very consistent and showed an increasing trend for IL-12 compared to the BCG or ESAT6:HspX:His primed and boosted groups. Fcγ2a used as a delivery vehicle supported the idea of selective uptake, inducing cross-presentation and forming a proper anti-tuberculosis response in context of Th1/Th2 and Th17/T-reg balances, which is important for protection and prevention of damage.

  8. Sensitive and specific detection of Crimean-Congo Hemorrhagic Fever Virus (CCHFV)—Specific IgM and IgG antibodies in human sera using recombinant CCHFV nucleoprotein as antigen in μ-capture and IgG immune complex (IC) ELISA tests

    Science.gov (United States)

    Emmerich, Petra; Mika, Angela; von Possel, Ronald; Rackow, Anne; Liu, Yang; Schmitz, Herbert; Sherifi, Kurtesh; Halili, Barie; Jakupi, Xhevat; Berisha, Lindita; Ahmeti, Salih

    2018-01-01

    As the most widespread tick-borne arbovirus causing infections in numerous countries in Asia, Africa and Europe, Crimean-Congo Hemorrhagic Fever Virus (CCHFV, family Nairoviridae) was included in the WHO priority list of emerging pathogens needing urgent Research & Development attention. To ensure preparedness for potential future outbreak scenarios, reliable diagnostic tools for identification of acute cases as well as for performance of seroprevalence studies are necessary. Here, the CCHFV ortholog of the major bunyavirus antigen, the nucleoprotein (NP), was recombinantly expressed in E.coli, purified and directly labeled with horseradish peroxidase (HRP). Employing this antigen, two serological tests, a μ-capture ELISA for the detection of CCHFV-specific IgM antibodies (BLACKBOX CCHFV IgM) and an IgG immune complex (IC) ELISA for the detection of CCHFV-specific IgG antibodies (BLACKBOX CCHFV IgG), were developed. Test performance was evaluated and compared with both in-house gold standard testing by IgM/IgG indirect immunofluorescence (IIF) and commercially available ELISA tests (VectoCrimean-CHF-IgM/IgG, Vector-Best, Russia) using a serum panel comprising paired samples collected in Kosovo during the years 2013–2016 from 15 patients with an acute, RT-PCR-confirmed CCHFV infection, and 12 follow-up sera of the same patients collected approximately one year after having overcome the infection. Reliably detecting IgM antibodies in all acute phase sera collected later than day 4 after onset of symptoms, both IgM ELISAs displayed excellent diagnostic and analytical sensitivity (100%, 95% confidence interval (CI): 85.2%–100.0%). While both IgG ELISAs readily detected the high IgG titers present in convalescent patients approximately one year after having overcome the infection (sensitivity 100%, 95% CI: 73.5%–100.0%), the newly developed BLACKBOX CCHFV IgG ELISA was superior to the commercial IgG ELISA in detecting the rising IgG titers during the acute phase

  9. Dicty_cDB: FC-BS14 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-BS14 (Link to dictyBase) - - - Contig-U16399-1 FC-BS14E (Li...nk to Original site) - - - - - - FC-BS14E 534 Show FC-BS14 Library FC (Link to library) Clone ID FC-BS14 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-BS/FC-BS14Q.Seq.d/ Representative seq. ID FC-BS...14E (Link to Original site) Representative DNA sequence >FC-BS14 (FC-BS14Q) /CSM/FC/FC-BS/FC-BS14Q.Seq.... vs CSM-cDNA Score E Sequences producing significant alignments: (bits) Value FC-BS14 (FC-BS

  10. Dicty_cDB: FC-AI17 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI17 (Link to dictyBase) - - - Contig-U15690-1 FC-AI17P (Li...nk to Original site) FC-AI17F 587 FC-AI17Z 626 FC-AI17P 1212 - - Show FC-AI17 Library FC (Link to library) Clone ID FC-AI...nal site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI17Q.Seq.d/ Representative seq. ID FC-AI...17P (Link to Original site) Representative DNA sequence >FC-AI17 (FC-AI17Q) /CSM/FC/FC-AI/FC-AI...slated Amino Acid sequence ANIATVGDFLKADTVVPKMIITYNKRKQGTDYLKAVIGPILSNVIKQELNLELKPNLVYA AIISEQEIRTGEKSTLDRNV

  11. Dicty_cDB: FC-AI18 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI18 (Link to dictyBase) - - - Contig-U15590-1 FC-AI18P (Li...nk to Original site) FC-AI18F 621 FC-AI18Z 703 FC-AI18P 1324 - - Show FC-AI18 Library FC (Link to library) Clone ID FC-AI...nal site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI18Q.Seq.d/ Representative seq. ID FC-AI...18P (Link to Original site) Representative DNA sequence >FC-AI18 (FC-AI18Q) /CSM/FC/FC-AI/FC-AI...AVWPLIPGYERA DGEKQYPVAAMLCNFTKPTPTTPSLLTHDEVVTFFHEFGHVMHNMSTKVHYSMFSGTSVE RDFVECPSQLFEFWCWNKDVLVNKLSGHXKDHSKKLPTDLVERMIAAKNLNVAI

  12. Dicty_cDB: FC-AI03 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI03 (Link to dictyBase) - - - Contig-U15833-1 FC-AI03P (Li...nk to Original site) FC-AI03F 690 FC-AI03Z 651 FC-AI03P 1341 - - Show FC-AI03 Library FC (Link to library) Clone ID FC-AI...nal site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI03Q.Seq.d/ Representative seq. ID FC-AI...03P (Link to Original site) Representative DNA sequence >FC-AI03 (FC-AI03Q) /CSM/FC/FC-AI/FC-AI...li*l*ivtlskv*qswyqvfcslmrftcwi*nv fht*ivhwsqhwhql*flqpivaiv*skapitifnlhmaslwif*ivl*sfvpfhiitmk sfkfspfvpqlki

  13. Evaluation of FcεRl-binding serum IgE in patients with ocular allergic diseases

    Directory of Open Access Journals (Sweden)

    Satoru Matsumoto

    1999-01-01

    Full Text Available We evaluated high-affinity receptor for IgE (FcεRI- binding serum IgE in patients with atopic keratoconjunctivitis (AKC; n=31 and with seasonal allergic conjunctivitis (SAC; n=13 by enzyme-linked immunosorbent assay (ELISA using a recombinant soluble form of the human FcεRIα ectodomain (soluble α. The quantities of FcεRI-binding IgE are compared with those of total IgE measured by a conventional sandwich ELISA. Both of the quantities of FcεRI-binding and total IgE in AKC were significantly larger than those in SAC (P<0.001. In contrast, the proportion of FcεRI- binding IgE (FcεRI-binding IgE/total IgE; % in SAC was significantly larger than that in AKC (P <0.001, although significant reverse correlation was observed between the proportion of FcεRI-binding IgE and total IgE in both AKC and SAC. Significantly, a higher proportion of FcεRI-binding IgE in SAC than that in AKC may reflect the differences in pathologic states of AKC and SAC that are caused by a disparity in immune responses in these diseases.

  14. Prolonged activity of a recombinant factor VIII-Fc fusion protein in hemophilia A mice and dogs

    Science.gov (United States)

    Dumont, Jennifer A.; Liu, Tongyao; Low, Susan C.; Zhang, Xin; Kamphaus, George; Sakorafas, Paul; Fraley, Cara; Drager, Douglas; Reidy, Thomas; McCue, Justin; Franck, Helen W. G.; Merricks, Elizabeth P.; Nichols, Timothy C.; Bitonti, Alan J.; Pierce, Glenn F.

    2012-01-01

    Despite proven benefits, prophylactic treatment for hemophilia A is hampered by the short half-life of factor VIII. A recombinant factor VIII-Fc fusion protein (rFVIIIFc) was constructed to determine the potential for reduced frequency of dosing. rFVIIIFc has an ∼ 2-fold longer half-life than rFVIII in hemophilia A (HemA) mice and dogs. The extension of rFVIIIFc half-life requires interaction of Fc with the neonatal Fc receptor (FcRn). In FcRn knockout mice, the extension of rFVIIIFc half-life is abrogated, and is restored in human FcRn transgenic mice. The Fc fusion has no impact on FVIII-specific activity. rFVIIIFc has comparable acute efficacy as rFVIII in treating tail clip injury in HemA mice, and fully corrects whole blood clotting time (WBCT) in HemA dogs immediately after dosing. Furthermore, consistent with prolonged half-life, rFVIIIFc shows 2-fold longer prophylactic efficacy in protecting HemA mice from tail vein transection bleeding induced 24-48 hours after dosing. In HemA dogs, rFVIIIFc also sustains partial correction of WBCT 1.5- to 2-fold longer than rFVIII. rFVIIIFc was well tolerated in both species. Thus, the rescue of FVIII by Fc fusion to provide prolonged protection presents a novel pathway for FVIII catabolism, and warrants further investigation. PMID:22246033

  15. Experimental investigation of small diameter two-phase closed thermosyphons charged with water, FC-84, FC-77 and FC-3283

    International Nuclear Information System (INIS)

    Jouhara, Hussam; Robinson, Anthony J.

    2010-01-01

    An experimental investigation of the performance of thermosyphons charged with water as well as the dielectric heat transfer liquids FC-84, FC-77 and FC-3283 has been carried out. The copper thermosyphon was 200 mm long with an inner diameter of 6 mm, which can be considered quite small compared with the vast majority of thermosyphons reported in the open literature. The evaporator length was 40 mm and the condenser length was 60 mm which corresponds with what might be expected in compact heat exchangers. With water as the working fluid two fluid loadings were investigated, that being 0.6 ml and 1.8 ml, corresponding to approximately half filled and overfilled evaporator section in order to ensure combined pool boiling and thin film evaporation/boiling and pool boiling only conditions, respectively. For the Fluorinert TM liquids, only the higher fill volume was tested as the aim was to investigate pool boiling opposed to thin film evaporation. Generally, the water-charged thermosyphon evaporator and condenser heat transfer characteristics compared well with available predictive correlations and theories. The thermal performance of the water-charged thermosyphon also outperformed the other three working fluids in both the effective thermal resistance as well as maximum heat transport capabilities. Even so, FC-84, the lowest saturation temperature fluid tested, shows marginal improvement in the heat transfer at low operating temperatures. All of the tested Fluorinert TM liquids offer the advantage of being dielectric fluids, which may be better suited for sensitive electronics cooling applications and were all found to provide adequate thermal performance up to approximately 30-50 W after which liquid entrainment compromised their performance.

  16. Rapid polyclonal desensitization with antibodies to IgE and FcεRIα.

    Science.gov (United States)

    Khodoun, Marat V; Kucuk, Zeynep Yesim; Strait, Richard T; Krishnamurthy, Durga; Janek, Kevin; Lewkowich, Ian; Morris, Suzanne C; Finkelman, Fred D

    2013-06-01

    Rapid desensitization, a procedure in which persons allergic to an antigen are treated at short intervals with increasing doses of that antigen until they tolerate a large dose, is an effective, but risky, way to induce temporary tolerance. We wanted to determine whether this approach can be adapted to suppress all IgE-mediated allergies in mice by injecting serially increasing doses of monoclonal antibodies (mAbs) to IgE or FcεRIα. Active and passive models of antigen- and anti-IgE mAb-induced IgE-mediated anaphylaxis were used. Mice were desensitized with serially increasing doses of anti-IgE mAb, anti-FcεRIα mAb, or antigen. Development of shock (hypothermia), histamine and mast cell protease release, cytokine secretion, calcium flux, and changes in cell number and FcεRI and IgE expression were evaluated. Rapid desensitization with anti-IgE mAb suppressed IgE-mediated immediate hypersensitivity; however, some mice developed mild anaphylaxis during desensitization. Rapid desensitization with anti-FcεRIα mAb that only binds FcεRI that is not occupied by IgE suppressed both active and passive IgE-mediated anaphylaxis without inducing disease. It quickly, but temporarily, suppressed IgE-mediated anaphylaxis by decreasing mast cell signaling through FcεRI, then slowly induced longer lasting mast cell unresponsiveness by removing membrane FcεRI. Rapid desensitization with anti-FcεRIα mAb was safer and longer lasting than rapid desensitization with antigen. A rapid desensitization approach with anti-FcεRIα mAb safely desensitizes mice to IgE-mediated anaphylaxis by inducing mast cell anergy and later removing all mast cell IgE. Rapid desensitization with an anti-human FcεRIα mAb may be able to prevent human IgE-mediated anaphylaxis. Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

  17. Discussion on the tropospheric concentrations of FC21

    Energy Technology Data Exchange (ETDEWEB)

    Crescentini, G.; Mangani, F.; Mastrogiamcomo, A.R.; Cappiello, A.; Bruner, F.

    1986-01-01

    FC21 tropospheric mixing ratios measured in air samples collected at different locations in the world are presented. Results of a campaign carried out at two locations in the Sahara desert where FC21 and FC11 mixing ratios were simultaneously determined in 180 samples are also shown. Though scattered high values have been found, the average background concentration of FC21 ranged between 0 and 1 pptv. 9 references, 1 figure, 2 tables.

  18. A benzenediamine derivate FC-99 attenuates lupus nephritis in MRL/lpr mice via inhibiting myeloid dendritic cell-secreted BAFF.

    Science.gov (United States)

    Ji, Jianjian; Xu, Jingjing; Li, Fanlin; Li, Xiaojing; Gong, Wei; Song, Yuxian; Dou, Huan; Hou, Yayi

    2016-05-01

    Myeloid dendritic cells (DCs) can produce B-cell-activating factor (BAFF) that modulates survival and differentiation of B cells and plays a pivotal role in the pathogenesis of systemic lupus erythematosus (SLE). Toll-like receptor 4 (TLR4) signaling has important functions in the process of BAFF production. Our previous study showed that a benzenediamine derivate FC-99 possesses anti-inflammation activity and directly interacts with interleukin-1 receptor-associated kinase 4 (IRAK4), which was a pivotal molecule in TLR4 signaling. In this study, we demonstrated that FC-99 attenuated lupus nephritis in the MRL/lpr mice. FC-99 also decreased the levels of total immunoglobulin G (IgG), total IgG2a and IgM in sera, as well as the activation of B cells in the spleens of MRL/lpr mice. Moreover, FC-99 inhibited abnormal activation of myeloid DCs in spleens and reduced the levels of BAFF in sera, spleens, and kidneys of MRL/lpr mice. Furthermore, upon TLR4 stimulation with lipopolysaccharide in vitro, FC-99 inhibited IRAK4 phosphorylation, as well as the activation and BAFF production in murine bone marrow-derived DCs. These data indicate that FC-99 attenuates lupus nephritis in MRL/lpr mice via inhibiting DC-secreted BAFF, suggesting that FC-99 may be a potential therapeutic candidate for the treatment of SLE. © The Author 2016. Published by ABBS Editorial Office in association with Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.

  19. Serum total IgG and IgG4 levels in thyroid eye disease

    Directory of Open Access Journals (Sweden)

    Sy A

    2016-10-01

    Full Text Available Aileen Sy, Rona Z Silkiss Department of Ophthalmology, California Pacific Medical Center, San Francisco, CA, USA Purpose: To investigate the relationship between immunoglobulin G (IgG4-related disease (IgG4-RD and thyroid eye disease (TED with respect to IgG levels. Patients and methods: A retrospective review of total IgG, IgG subclass, and thyroid stimulating immunoglobulin (TSI levels in 24 patients with TED. Results: Five patients (20.8% demonstrated serum IgG4 levels consistent with IgG4-RD without any additional systemic disease. Total IgG and IgG subclass levels were found to be an inadequate proxy for TSI elevation. Conclusion: There may be a subtype of TED patients with elevated IgG4 in the absence of IgG4-RD systemic findings. Keywords: thyroid eye disease, IgG subclass, IgG4, Graves’ disease, Graves’ ophthalmopathy, IgG4-RD

  20. Treatment with a human recombinant monoclonal IgG antibody against oxidized LDL in atherosclerosis-prone pigs reduces cathepsin S in coronary lesions

    DEFF Research Database (Denmark)

    Poulsen, Christian Bo; Al-Mashhadi, Ahmed Ludvigsen; von Wachenfeldt, Karin

    2016-01-01

    and results Thirty-eight hypercholesterolemic minipigs with defective LDL receptors were injected with an oxLDL antibody or placebo weekly for 12 weeks. An 18F-fluorodeoxyglucose positron emission tomography (FDG PET) scan (n = 9) was performed before inclusion and after 3 months of treatment. Blood samples....... There was no effect of treatment on plasma lipid profile, vascular FDG-PET signal or the amount of atherosclerosis in any of the examined arteries. However, immunostaining of coronary lesions revealed reduced cathepsin S positivity in the treated group compared with placebo (4.8% versus 8.2% of intima area, p = 0.......03) with no difference in CD68 or CD163 positivity. Conclusions In hypercholesterolemic minipigs, treatment with a human recombinant monoclonal antibody against oxLDL reduced cathepsin S in coronary lesions without any effect on the burden of atherosclerosis or aortic FDG-PET signal....

  1. Serum IgG2 and tissue IgG2 plasma cell elevation in orbital IgG4-related disease (IgG4-RD): Potential use in IgG4-RD assessment.

    Science.gov (United States)

    Chan, Anita S Y; Mudhar, Hardeep; Shen, Sunny Yu; Lang, Stephanie S; Fernando, Malee; Hilmy, Maryam Hazly; Guppy, Naomi Jayne; Rennie, Ian; Dunkley, Lisa; Al Jajeh, Issam

    2017-11-01

    To determine the role of serum and tissue IgG2 in orbital biopsies with the histological features of IgG4-related disease (IgG4-RD) in comparison with non-IgG4-related orbital inflammatory disorders (OID), including autoimmune disorders. This is an international (Sheffield, UK, and Singapore) collaborative, retrospective case review of 69 patients (38 from Singapore National Eye Centre and 31 from Royal Hallamshire Hospital, Sheffield) with orbital inflammatory biopsies between 2002 and 2016. Clinical information and histology were reviewed and cases were classified into three groups: Group 1: IgG4-RD orbital inflammation (n=43); Group 2: idiopathic OID (n=12) and Group 3: autoimmune OID (n=14). Serum IgG1, IgG2, IgG3 and IgG4 levels were collated where available and immunohistochemistry (IHC) for tissue IgG2 plasma cells was performed. Dual IHC showed IgG2 plasma cells as a distinct population from IgG4 plasma cells. Significant (twofold) serum IgG2 elevation was noted among IgG4-RD (group 1), idiopathic (group 2) and autoimmune OID (group 3). Similarly, significant elevation of tissue IgG2 plasma cells was also seen among IgG4-RD (group 1), idiopathic and autoimmune OID (groups 2 and 3). Significant elevations of serum IgG2 and tissue IgG2 plasma cells are present in orbital IgG4-RD in comparison with non-IgG4 orbital inflammation (idiopathic and autoimmune OID), suggesting that IgG2 may play a role in IgG4-RD. A serum IgG2 cut-off >5.3 g/L was found to be 80% sensitive and 91.7% specific for orbital IgG4-RD, with an accuracy of 0.90. Tissue IgG2 and IgG4 subclass reporting may provide additional insight regarding the 'IgG4-RD' pathogenesis. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  2. Targeting IgG in Arthritis: Disease Pathways and Therapeutic Avenues

    Directory of Open Access Journals (Sweden)

    Kutty Selva Nandakumar

    2018-02-01

    Full Text Available Rheumatoid arthritis (RA is a polygenic and multifactorial syndrome. Many complex immunological and genetic interactions are involved in the final outcome of the clinical disease. Autoantibodies (rheumatoid factors, anti-citrullinated peptide/protein antibodies are present in RA patients’ sera for a long time before the onset of clinical disease. Prior to arthritis onset, in the autoantibody response, epitope spreading, avidity maturation, and changes towards a pro-inflammatory Fc glycosylation phenotype occurs. Genetic association of epitope specific autoantibody responses and the induction of inflammation dependent and independent changes in the cartilage by pathogenic autoantibodies emphasize the crucial contribution of antibody-initiated inflammation in RA development. Targeting IgG by glyco-engineering, bacterial enzymes to specifically cleave IgG/alter N-linked Fc-glycans at Asn 297 or blocking the downstream effector pathways offers new avenues to develop novel therapeutics for arthritis treatment.

  3. High Affinity IgE-Fc Receptor alpha and gamma Subunit Interactions

    International Nuclear Information System (INIS)

    Rashid, A.; Housden, J. E. M.; Sabban, S.; Helm, B.

    2014-01-01

    Objective: To explore the relationships between the subunits (alpha, beta and gamma) of the high affinity IgE receptor (Fc and RI) and its ability to mediate transmembrane signaling. Study Design: Experimental study. Place and Duration of Study: Department of Molecular Biology and Biotechnology, University of Sheffield, UK, from 2008 to 2009. Methodology: The approach employed was to create a chimera (human alpha-gamma-gamma) using the extracellular (EC) domain of the human high affinity IgE receptor. The alpha subunit (huFc and RIalpha) of IgE receptor was spliced onto the rodent gamma TM and cytoplasmic domain (CD). This was transfected into the Rat Basophilic Leukemia cell line in order to assess the possibility of selectively activating cells transfected with this single pass construct for antigen induced mediator release. Results: The RBLs cell lines transfected with the huFc and RIalpha/gamma/gamma cDNA constructs were assessed for the cell surface expression of the huFc and RIalpha subunit and the response to the antigenic stimulus by looking for degranulation and intracellular Ca2+ mobilisation. The results obtained showed the absence of huFc and RIalpha subunit expression on the surface of transfected cells as seen by flowcytometric studies, beta-hexosaminidase assays and intracellular calcium mobilisation studies. Conclusion: In the present study the grounds for non-expression of huFc and RIalpha/gamma/gamma cDNA remains elusive but may be due to the fact that the human-rodent chimeric receptors are assembled differently than the endogenous rodent receptors as seen in study in which COS 7 cells were transfected with human/rat chimeric complexes. (author)

  4. Serum levels of IgG and IgG4 in Hashimoto thyroiditis.

    Science.gov (United States)

    Kawashima, Sachiko-Tsukamoto; Tagami, Tetsuya; Nakao, Kanako; Nanba, Kazutaka; Tamanaha, Tamiko; Usui, Takeshi; Naruse, Mitsuhide; Minamiguchi, Sachiko; Mori, Yusuke; Tsuji, Jun; Tanaka, Issei; Shimatsu, Akira

    2014-03-01

    Although IgG4-related disease is characterized by extensive infiltration of IgG4-positive plasma cells and lymphocytes of various organs, the details of this systemic disease are still unclear. We screened serum total IgG levels in the patients with Hashimoto thyroiditis (HT) to illustrate the prevalence of IgG4-related thyroiditis in HT. Twenty-four of 94 patients with HT (25.5%) had elevated serum IgG levels and their serum IgG4 was measured. Five of the 24 cases had more than 135 mg/dL of IgG4, which is the serum criterion of IgG4-related disease. One was a female patient who was initially treated as Graves' disease and rapidly developed a firm goiter and hypothyroidism. The biopsy of her thyroid gland revealed that follicular cells were atrophic with squamous metaplasia, replaced with fibrosis, which was compatible with the fibrous variant of HT. Immunohistochemical examination revealed diffuse infiltration of IgG4-positive plasma cells, and the serum IgG4 level was 179 mg/dL. The levels of IgG and IgG4 were positively correlated with the titers of anti-thyroglobulin antibody or anti-thyroid peroxidase antibody. In conclusion, at least a small portion of patients with HT with high titers of anti-thyroid antibodies may overlap the IgG4-related thyroiditis.

  5. IgG4-related nephropathy.

    Science.gov (United States)

    Quattrocchio, Giacomo; Roccatello, Dario

    2016-08-01

    IgG4-related disease (IgG4-RD) is a recently recognized disorder, often with multiple organ involvement, characterized by dense tissue infiltration of IgG4-positive plasma cells, storiform fibrosis, obliterative phlebitis and frequently elevated serum IgG4 concentration. The kidney can be involved either directly or indirectly. The most frequent direct renal manifestations of IgG4-RD are IgG4-related tubulointerstitial nephritis (TIN) and membranous glomerulonephropathy. Retroperitoneal fibrosis (RPF) is another condition that is frequently IgG4-related and that can indirectly affect the kidney causing ureteral obstruction and hydronephrosis. Contrast-enhanced computerized tomography, magnetic resonance imaging and (18)F-fluorodeoxyglucose positron emission tomography/computed tomography show different imaging findings and are useful tools for monitoring therapeutic response. Steroid treatment is the first line of therapy, but relapsing or refractory forms of the disease are frequently observed and require more aggressive therapeutic approaches. At our centre, we treated three cases of aggressive IgG4-related TIN and two cases of IgG4-related RPF with an intensified, immune suppressive protocol, obtaining good results without severe adverse effects.

  6. IgG4-Related Sclerosing Cholangitis.

    Science.gov (United States)

    Nakazawa, Takahiro; Shimizu, Shuya; Naitoh, Itaru

    2016-08-01

    More men than women develop immunoglobulin G4-related sclerosing cholangitis (IgG4-SC). Age at clinical onset is significantly older in patients with IgG4-SC. Patients with IgG4-SC appear similar to those with cholangiocarcinoma and primary sclerosing cholangitis (PSC). The association between IgG4-SC and autoimmune pancreatitis (AIP) is useful for the diagnosis of IgG4-SC. However, some IgG4-SC cases are isolated from AIP and are difficult to diagnose. The authors focus on three distinct features of IgG4-SC. First, diffuse inflammation induces a longer stenosis on cholangiography in contrast to the short stenosis of patients with PSC. Second, fibroinflammatory involvement is observed mainly in the stroma of the bile duct wall, whereas the bile duct epithelium is intact. Third, steroid therapy results in remarkable improvement. Although the prognosis of patients with IgG4-SC is good, some cases have developed portal hypertension and liver cirrhosis during their clinical course. Further study is needed to elucidate the long-term outcomes and mechanism of IgG4-SC. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  7. Conjugation of hydroxyapatite nanocrystals with human immunoglobulin G for nanomedical applications.

    Science.gov (United States)

    Iafisco, Michele; Varoni, Elena; Di Foggia, Michele; Pietronave, Stefano; Fini, Milena; Roveri, Norberto; Rimondini, Lia; Prat, Maria

    2012-02-01

    Inorganic nanosized drug carriers are a promising field in nanomedicine applied to cancer. Their conjugation with antibodies combines the properties of the nanoparticles themselves with the specific and selective recognition ability of the antibodies to antigens. Biomimetic carbonate-hydroxyapatite (HA) nanoparticles were synthesized and fully characterized; human IgGs, used as model antibodies, were coupled to these nanocrystals. The maximum loading amount, the interaction modelling, the preferential orientation and the secondary structure modifications were evaluated using theoretical models (Langmuir, Freundlich and Langmuir-Freundlich) spectroscopic (UV-Vis, Raman), calorimetric (TGA), and immunochemical techniques (ELISA, Western Blot). HA nanoparticles of about 30 nm adsorbed human IgGs, in a dose-dependent, saturable and stable manner with micromolar affinity and adsorption capability around 2.3 mg/m(2). Adsorption isotherm could be described by Langmuir-Freundlich model, and was due to both energetically homogeneous and heterogeneous binding sites on HA surface, mainly of electrostatic nature. Binding did not induce secondary structure modification of IgGs. A preferential IgG end-on orientation with the involvement of IgG Fc moiety in the adsorption seems most probable due to the steric hindrance of their Fab domains. Biomimetic HA nanocrystals are suitable substrates to produce nanoparticles which can be functionalized with antibodies for efficient targeted drug delivery to tumours. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Dicty_cDB: FC-AI12 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI12 (Link to dictyBase) - - - Contig-U15484-1 FC-AI12Z (Li...nk to Original site) - - FC-AI12Z 614 - - - - Show FC-AI12 Library FC (Link to library) Clone ID FC-AI12 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI12Q.Seq.d/ Representative seq. ID FC-AI...12Z (Link to Original site) Representative DNA sequence >FC-AI12 (FC-AI12Q) /CSM/FC/FC-AI/FC-AI12Q.Seq....EKIVRRI ELLDGITCYRNEKAKDEIVLTGNSLELLSQSCATIQLRSAIKYKDVRKFLDGIYVSERNV LESN*in*riys

  9. Dicty_cDB: FC-AI19 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI19 (Link to dictyBase) - - - Contig-U15115-1 FC-AI19Z (Li...nk to Original site) - - FC-AI19Z 661 - - - - Show FC-AI19 Library FC (Link to library) Clone ID FC-AI19 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI19Q.Seq.d/ Representative seq. ID FC-AI...19Z (Link to Original site) Representative DNA sequence >FC-AI19 (FC-AI19Q) /CSM/FC/FC-AI/FC-AI19Q.Seq....lmrqswvkkiesi*lvl krrkkkknnkkkkkkkkkkklfn*lvnkkn*ik*kkllcnqkk Frame B: ---*ekaieilsklfsin*kfn**ysiiigkkstkyq

  10. Dicty_cDB: FC-AI14 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI14 (Link to dictyBase) - - - Contig-U16280-1 FC-AI14Z (Li...nk to Original site) - - FC-AI14Z 671 - - - - Show FC-AI14 Library FC (Link to library) Clone ID FC-AI14 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI14Q.Seq.d/ Representative seq. ID FC-AI...14Z (Link to Original site) Representative DNA sequence >FC-AI14 (FC-AI14Q) /CSM/FC/FC-AI/FC-AI14Q.Seq....nqrllv*lvvlskklqllnsnqsfkfkkvq rmkknsvkntkn*rfvllt*nlkslkrmpksknsptkliifilkly Frame B: ---lkdl*krtphl*stcfhhptlcssrrfclwslnai

  11. Dicty_cDB: FC-AI15 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI15 (Link to dictyBase) - G01730 DDB0214993 Contig-U15123-1 FC-AI...15E (Link to Original site) - - - - - - FC-AI15E 856 Show FC-AI15 Library FC (Link to library) Clone ID FC-AI...3-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI15Q.Se...q.d/ Representative seq. ID FC-AI15E (Link to Original site) Representative DNA sequence >FC-AI15 (FC-AI15Q) /CSM/FC/FC-AI/FC-AI...AAAAAAAATA sequence update 1996.12.24 Translated Amino Acid sequence kt*riyi*KMMIKYITIAILFIASLVKADLQFSLCPTCV

  12. Dicty_cDB: FC-AI24 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI24 (Link to dictyBase) - - - - FC-AI24Z (Link to Original site) - - FC-AI...24Z 693 - - - - Show FC-AI24 Library FC (Link to library) Clone ID FC-AI24 (Link to dictyBas...e) Atlas ID - NBRP ID - dictyBase ID - Link to Contig - Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI...24Q.Seq.d/ Representative seq. ID FC-AI24Z (Link to Original s...ite) Representative DNA sequence >FC-AI24 (FC-AI24Q) /CSM/FC/FC-AI/FC-AI24Q.Seq.d/ XXXXXXXXXXAAATTAGAAAACAAA

  13. Dicty_cDB: FC-AI06 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI06 (Link to dictyBase) - - - Contig-U16465-1 FC-AI06E (Li...nk to Original site) - - - - - - FC-AI06E 1138 Show FC-AI06 Library FC (Link to library) Clone ID FC-AI06 (L...//dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI06Q.Seq.d/ Representative seq. ID FC-AI...06E (Link to Original site) Representative DNA sequence >FC-AI06 (FC-AI06Q) /CSM/FC/FC-AI/FC-AI06Q.Seq...FGRGIDIERVNVVINYDMAESADTYLHRVGRAGRFGTK GLAISFVPSKEDPVLEQVQSKFVVSIKELVATPDPSTYMSG*kkkkkkkknlfvlksikk k*kkk*in

  14. Dicty_cDB: FC-AI09 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI09 (Link to dictyBase) - - - Contig-U16149-1 FC-AI09Z (Li...nk to Original site) - - FC-AI09Z 591 - - - - Show FC-AI09 Library FC (Link to library) Clone ID FC-AI09 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI09Q.Seq.d/ Representative seq. ID FC-AI...09Z (Link to Original site) Representative DNA sequence >FC-AI09 (FC-AI09Q) /CSM/FC/FC-AI/FC-AI09Q.Seq....*tkl ik*ilifykiknnkkkkkk Frame B: ---gt*kvpeflailfkrmasrsvlwy*rcltkakkglkapqtltik

  15. Preclinical evaluation of VIS513, a therapeutic antibody against dengue virus, in non-human primates.

    Science.gov (United States)

    Ong, Eugenia Z; Budigi, Yadunanda; Tan, Hwee Cheng; Robinson, Luke N; Rowley, Kirk J; Winnett, Alexander; Hobbie, Sven; Shriver, Zachary; Babcock, Gregory J; Ooi, Eng Eong

    2017-08-01

    Despite useful in vivo activity, no therapeutic against dengue virus (DENV) has demonstrated efficacy in clinical trials. Herein, we explored dosing and virological endpoints to guide the design of human trials of VIS513, a pan-serotype anti-DENV IgG1 antibody, in non-human primates (NHPs). Dosing VIS513 pre- or post-peak viremia in NHPs neutralized infectious DENV although RNAemia remained detectable post-treatment; differential interaction of human IgGs with macaque Fc-gamma receptors may delay clearance of neutralized DENV. Our findings suggest useful antiviral utility of VIS513 and highlight an important consideration when evaluating virological endpoints of trials for anti-DENV biologics. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  16. Cutoff Values of Serum IgG4 and Histopathological IgG4+ Plasma Cells for Diagnosis of Patients with IgG4-Related Disease

    Directory of Open Access Journals (Sweden)

    Yasufumi Masaki

    2012-01-01

    Full Text Available IgG4-related disease is a new disease classification established in Japan in the 21st century. Patients with IgG4-related disease display hyper-IgG4-gammaglobulinemia, massive infiltration of IgG4+ plasma cells into tissue, and good response to glucocorticoids. Since IgG4 overexpression is also observed in other disorders, it is necessary to diagnose IgG4-related disease carefully and correctly. We therefore sought to determine cutoff values for serum IgG4 and IgG4/IgG and for IgG4+/IgG+ plasma cells in tissue diagnostic of IgG4-related disease. Patients and Methods. We retrospectively analyzed serum IgG4 concentrations and IgG4/IgG ratio and IgG4+/IgG+ plasma cell ratio in tissues of 132 patients with IgG4-related disease and 48 patients with other disorders. Result. Serum IgG4 >135  mg/dl demonstrated a sensitivity of 97.0% and a specificity of 79.6% in diagnosing IgG4-related disease, and serum IgG4/IgG ratios >8% had a sensitivity and specificity of 95.5% and 87.5%, respectively. IgG4+cell/IgG+ cell ratio in tissues >40% had a sensitivity and specificity of 94.4% and 85.7%, respectively. However, the number of IgG4+ cells was reduced in severely fibrotic parts of tissues. Conclusion. Although a recent unanimous consensus of all relevant researchers in Japan recently established the diagnostic criteria for IgG4-related disease, findings such as ours indicate that further discussion is needed.

  17. At least two Fc Neu5Gc residues of monoclonal antibodies are required for binding to anti-Neu5Gc antibody

    OpenAIRE

    Yu, Chuanfei; Gao, Kai; Zhu, Lei; Wang, Wenbo; Wang, Lan; Zhang, Feng; Liu, Chunyu; Li, Meng; Wormald, Mark R.; Rudd, Pauline M.; Wang, Junzhi

    2016-01-01

    Two non-human glycan epitopes, galactose-Į-1,3-galactose (Į-gal) and Neu5Gc-Į-2-6-galactose (Neu5Gc) have been shown to be antigenic when attached to Fab oligosaccharides of monoclonal antibodies (mAbs) , while Į-gal attached to Fc glycans were not. However, the antigenicity of Neu5Gc on the Fc glycans remains unclear in the context that most mAbs carry only Fc glycans. After studying two clinical mAbs carrying significant amounts of Fc Neu5Gc, we show that their binding activity with anti-Ne...

  18. Genetic association of multiple sclerosis with the marker rs391745 near the endogenous retroviral locus HERV-Fc1: analysis of disease subtypes

    DEFF Research Database (Denmark)

    Hansen, Bettina; Oturai, Annette Bang; Harbo, Hanne F

    2011-01-01

    We have previously described the occurrence of multiple sclerosis (MS) to be associated with human endogenous retroviruses, specifically the X-linked viral locus HERV-Fc1. The aim of this study was to investigate a possible association of the HERV-Fc1 locus with subtypes of MS. MS patients......-Fc1 locus (p = 0.003), while primary progressive disease was not. The ability to see genetic differences between subtypes of MS near this gene speaks for the involvement of the virus HERV-Fc1 locus in modifying the disease course of MS....

  19. Clearance of red cells by monoclonal IgG3 anti-D in vivo is affected by the VF polymorphism of Fcgamma RIIIa (CD16)

    NARCIS (Netherlands)

    Kumpel, B. M.; de Haas, M.; Koene, H. R.; van de Winkel, J. G. J.; Goodrick, M. J.

    2003-01-01

    Human red cells (RBC) coated with IgG anti-D are cleared from the circulation to the spleen by macrophages which express IgG receptors (Fcgamma R). Polymorphisms of Fcgamma RIIa and Fcgamma RIIIa affect IgG binding in vitro, and may alter the efficiency of clearance of immune complexes in vivo. In a

  20. Stabilization and augmentation of circulating AIM in mice by synthesized IgM-Fc.

    Directory of Open Access Journals (Sweden)

    Toshihiro Kai

    Full Text Available Owing to rapid and drastic changes in lifestyle and eating habits in modern society, obesity and obesity-associated diseases are among the most important public health problems. Hence, the development of therapeutic approaches to regulate obesity is strongly desired. In view of previous work showing that apoptosis inhibitor of macrophage (AIM blocks lipid storage in adipocytes, thereby preventing obesity caused by a high-fat diet, we here explored a strategy to augment circulating AIM levels. We synthesized the Fc portion of the soluble human immunoglobulin (IgM heavy chain and found that it formed a pentamer containing IgJ as natural IgM does, and effectively associated with AIM in vitro. When we injected the synthesized Fc intravenously into mice lacking circulating IgM, it associated with endogenous mouse AIM, protecting AIM from renal excretion and preserving the circulating AIM levels. As the synthesized Fc lacked the antigen-recognizing variable region, it provoked no undesired immune response. In addition, a challenge with the Fc-human AIM complex in wild-type mice, which exhibited normal levels of circulating IgM and AIM, successfully maintained the levels of the human AIM in mouse blood. We also observed that the human AIM was effectively incorporated into adipocytes in visceral fat tissue, suggesting its functionality against obesity. Thus, our findings reveal potent strategies to safely increase AIM levels, which could form the basis for developing novel therapies for obesity.

  1. CERTIFICATION REPORT The certification of the mass concentration of immunoglobulin G proteinase 3 anti-neutrophil cytoplasmic autoantibodies (IgG PR3 ANCA) in human serum: ERM® - DA483/IFCC

    OpenAIRE

    MONOGIOUDI EVANTHIA; HUTU DANA PETRONELA; CHAROUD-GOT JEAN; SHELDON JOANNA; SCHIMMEL HEINZ; TRAPMANN STEFANIE; MERONI PIERLUIGI; EMONS HENDRIK; ZEGERS INGRID

    2017-01-01

    This report describes the production and certification of ERM-DA483/IFCC, a serum protein reference material intended for the standardisation of measurements of immunoglobulin G proteinase 3 anti-neutrophil cytoplasmic autoantibodies (IgG PR3 ANCA). The material was produced according to ISO Guide 34:2009 [ ] and is certified in accordance with ISO Guide 35:2006. The raw material used to prepare ERM-DA483/IFCC was a plasmapheresis material containing a high concentration of IgG PR3 ANCA. A...

  2. A methodological approach for production and purification of polyclonal antibody against dog IgG.

    Science.gov (United States)

    Sadeghi, Somayeh; Aghebati-Maleki, Leili; Nozari, Samira; Majidi, Jafar

    2018-01-01

    Antibodies are a class of biomolecules that has an important role in the immune system and lots of applications in biotechnological methods and in pharmaceutics. Production and purification of antibodies in laboratory animals is one of the first ways to manufacture of these prominent tools. The obtained antibodies from these process could be used in various types of bioassay techniques such as enzyme linked immunosorbent assay (ELISA), radioimmunoassay, etc. Also, antibodies employed in diagnostics applications in humans and other animals in order to detect specific antigens. In this study, we aimed to produce and purify anti-dog IgG via immunizing rabbits with dog IgG in combination with Freund's adjuvant. Polyclonal IgG were purified by ion exchange chromatography and then the purified antibody was labeled with horse radish peroxidase (HPR). Direct ELISA was used to determine the optimum titer and cross-reactivity of HRP conjugated IgG. The purity of various IgG preparations and the optimum dilution of prepared HRP conjugated IgG, respectively, was about 95.00% and 1:8000. This study showed that efficiency ion-exchange chromatography could be an appropriate method for purification of IgG antibodies. This antibody could be a useful tool for future dog immune diagnosis tests. This product characterization shown here sets the foundations for future work on dog IgGs.

  3. IgG4-gerelateerde ziekte

    NARCIS (Netherlands)

    Maillette de Buy Wenniger, Lucas J.; Doorenspleet, Marieke E.; Verheij, Joanne; de Vries, Niek; Beuers, Ulrich

    2013-01-01

    The diagnosis IgG4-related disease (IgG4-RD) is often difficult to make. The clinical spectrum is diverse, with a variety of organ systems that may be affected simultaneously or sequentially. Patients often present with symptoms that mimic a malignant disease, for example, symptoms compatible with a

  4. IgG4-related disease.

    Science.gov (United States)

    Bozzalla Cassione, Emanuele; Stone, John H

    2017-05-01

    Remarkable insights have been gleaned recently with regard to the pathophysiology of IgG4-related disease (IgG4-RD). These findings have direct implications for the development of targeted strategies for the treatment of this condition. Oligoclonal expansions of cells of both the B and T lymphocyte lineages are present in the blood of patients with IgG4-RD. Oligoclonal expansions of plasmablasts are a good biomarker for disease activity. An oligoclonally expanded population of CD4+ cytotoxic T lymphocytes is found not only in the peripheral blood but also at tissue sites of active disease. This cell elaborates cytokines that may drive the fibrosis characteristic of IgG4-RD. T follicular helper cells (Tfhc), particularly the Tfhc2 subset, appear to play a major role in driving the class switch to IgG4 that typifies this disease. The relationship between malignancy and IgG4-RD remains an area of interest. Advances in understanding the pathophysiology of IgG4-RD have proceeded swiftly, leading to the identification of a number of potential targeted treatment strategies. The completion of classification criteria for IgG4-RD, an effort supported jointly by the American College of Rheumatology and the European League Against Rheumatism, will further facilitate studies on this disease.

  5. IgG4 antibodies in Egyptian patients with schistosomiasis

    NARCIS (Netherlands)

    Iskander, R.; Das, P. K.; Aalberse, R. C.

    1981-01-01

    Serum immunoglobulins were determined in 40 Egyptian patients with schistosomiasis. In addition to the well-established elevation in total IgE, a striking imbalance in the IgG subclass levels was found: IgG3 and IgG4 levels were markedly elevated, whereas IgG2 levels were normal. The IgG4 level did

  6. Syk-dependent tyrosine phosphorylation of 3BP2 is required for optimal FcRγ-mediated phagocytosis and chemokine expression in U937 cells.

    Science.gov (United States)

    Chihara, Kazuyasu; Kato, Yuji; Yoshiki, Hatsumi; Takeuchi, Kenji; Fujieda, Shigeharu; Sada, Kiyonao

    2017-09-13

    The adaptor protein c-Abl SH3 domain binding protein-2 (3BP2) is tyrosine phosphorylated by Syk in response to cross-linking of antigen receptors, which in turn activates various immune responses. Recently, a study using the mouse model of cherubism, a dominant inherited disorder caused by mutations in the gene encoding 3BP2, showed that 3BP2 is involved in the regulation of phagocytosis mediated by Fc receptor for IgG (FcγR) in macrophages. However, the molecular mechanisms underlying 3BP2-mediated regulation of phagocytosis and the physiological relevance of 3BP2 tyrosine phosphorylation remains elusive. In this study, we established various gene knockout U937 cell lines using the CRISPR/Cas9 system and found that 3BP2 is rapidly tyrosine phosphorylated by Syk in response to cross-linking of FcγRI. Depletion of 3BP2 caused significant reduction in the Fc receptor γ chain (FcRγ)-mediated phagocytosis in addition to the FcγRI-mediated induction of chemokine mRNA for IL-8, CCL3L3 and CCL4L2. Syk-dependent tyrosine phosphorylation of 3BP2 was required for overcoming these defects. Finally, we found that the PH and SH2 domains play important roles on FcγRI-mediated tyrosine phosphorylation of 3BP2 in HL-60 cells. Taken together, these results indicate that Syk-dependent tyrosine phosphorylation of 3BP2 is required for optimal FcRγ-mediated phagocytosis and chemokine expression.

  7. Dicty_cDB: FC-BR21 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-BR21 (Link to dictyBase) - - - Contig-U15384-1 | Contig-U16443-1 FC-BR2...1P (Link to Original site) FC-BR21F 551 FC-BR21Z 122 FC-BR21P 673 - - Show FC-BR21 Library FC (L...ink to library) Clone ID FC-BR21 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Cont...ig-U15384-1 | Contig-U16443-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-BR/FC-BR2...1Q.Seq.d/ Representative seq. ID FC-BR21P (Link to Original site) Representative DNA sequence >FC-BR21 (FC-BR2

  8. Dicty_cDB: FC-AI07 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI07 (Link to dictyBase) - - - Contig-U15296-1 | Contig-U15756-1 FC-AI...07P (Link to Original site) FC-AI07F 580 FC-AI07Z 723 FC-AI07P 1303 - - Show FC-AI07 Library FC (...Link to library) Clone ID FC-AI07 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Con...tig-U15296-1 | Contig-U15756-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI...07Q.Seq.d/ Representative seq. ID FC-AI07P (Link to Original site) Representative DNA sequence >FC-AI07 (FC-AI

  9. Dicty_cDB: FC-AI22 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI22 (Link to dictyBase) - - - Contig-U15369-1 | Contig-U15732-1 FC-AI...22P (Link to Original site) FC-AI22F 583 FC-AI22Z 683 FC-AI22P 1266 - - Show FC-AI22 Library FC (...Link to library) Clone ID FC-AI22 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Con...tig-U15369-1 | Contig-U15732-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI...22Q.Seq.d/ Representative seq. ID FC-AI22P (Link to Original site) Representative DNA sequence >FC-AI22 (FC-AI

  10. Dicty_cDB: FC-AI08 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AI08 (Link to dictyBase) - G01729 DDB0233148 Contig-U14939-1 FC-AI...08P (Link to Original site) FC-AI08F 654 FC-AI08Z 563 FC-AI08P 1217 - - Show FC-AI08 Library FC (Link... to library) Clone ID FC-AI08 (Link to dictyBase) Atlas ID - NBRP ID G01729 dictyBase ID DDB0233148 Link to ...Contig Contig-U14939-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-AI/FC-AI...08Q.Seq.d/ Representative seq. ID FC-AI08P (Link to Original site) Representative DNA sequence >FC-AI08 (FC-AI

  11. IgG4-related spinal pachymeningitis.

    Science.gov (United States)

    Lu, Zhang; Tongxi, Liu; Jie, Luo; Yujuan, Jiao; Wei, Jiang; Xia, Liu; Yumin, Zheng; Xin, Lu

    2016-06-01

    The aim of this study is to study the clinical, laboratory, imaging pathology, and prognosis features of IgG4-related spinal pachymeningitis. We worked with a 55-year-old man suffering from IgG4-related spinal pachymeningitis who had the most widespread lesion in his dura mater. We also review previous related studies and discuss the clinical characteristics of this rare disease. In total, eight IgG4-related spinal pachymeningitis patients have been reported in the literature since 2009. They were mostly male patients, 51.7 ± 11.9 years old on average. Cervical and thoracic vertebrae were the most common sites for lesions. The most prominent symptom was varying numbness and weakness of the limbs and/or body associated with spinal cord compression. There was one patient (1/5) with elevated serum IgG4 levels and three patients (3/3) with increased cerebrospinal fluid (CSF) IgG4 index. Positive histopathologic findings are the strongest basis for a diagnosis. All the patients with IgG4-related spinal pachymeningitis responded well to glucocorticoid therapy. IgG4-related spinal pachymeningitis is an orphan disease that mainly occurs in cervical and thoracic vertebrae. Older males are the most susceptible group. Serum IgG4 levels were consistently normal in these cases, so analysis of CSF for IgG4 production (IgG4 index) could become a useful tool. Pathological findings remain the gold standard for diagnosis. Most patients responded favorably to glucocorticoid treatment.

  12. Rac1 switching at the right time and location is essential for Fcγ receptor-mediated phagosome formation.

    Science.gov (United States)

    Ikeda, Yuka; Kawai, Katsuhisa; Ikawa, Akira; Kawamoto, Kyoko; Egami, Youhei; Araki, Nobukazu

    2017-08-01

    Lamellipodia are sheet-like cell protrusions driven by actin polymerization mainly through Rac1, a GTPase molecular switch. In Fcγ receptor-mediated phagocytosis of IgG-opsonized erythrocytes (IgG-Es), Rac1 activation is required for lamellipodial extension along the surface of IgG-Es. However, the significance of Rac1 deactivation in phagosome formation is poorly understood. Our live-cell imaging and electron microscopy revealed that RAW264 macrophages expressing a constitutively active Rac1 mutant showed defects in phagocytic cup formation, while lamellipodia were formed around IgG-Es. Because activated Rac1 reduced the phosphorylation levels of myosin light chains, failure of the cup formation is probably due to inhibition of actin/myosin II contractility. Reversible photo-manipulation of the Rac1 switch in macrophages fed with IgG-Es could phenocopy two lamellipodial motilities: outward-extension and cup-constriction by Rac1 ON and OFF, respectively. In conjunction with fluorescence resonance energy transfer imaging of Rac1 activity, we provide a novel mechanistic model of phagosome formation spatiotemporally controlled by Rac1 switching within a phagocytic cup. © 2017. Published by The Company of Biologists Ltd.

  13. Site-selective conjugation of an anticoagulant aptamer to recombinant albumins and maintenance of neonatal Fc receptor binding

    Science.gov (United States)

    Schmøkel, Julie; Voldum, Anders; Tsakiridou, Georgia; Kuhlmann, Matthias; Cameron, Jason; Sørensen, Esben S.; Wengel, Jesper; Howard, Kenneth A.

    2017-05-01

    Aptamers are an attractive molecular medicine that offers high target specificity. Nucleic acid-based aptamers, however, are prone to nuclease degradation and rapid renal excretion that require blood circulatory half-life extension enabling technologies. The long circulatory half-life, predominately facilitated by engagement with the cellular recycling neonatal Fc receptor (FcRn), and ligand transport properties of albumin promote it as an attractive candidate to improve the pharmacokinetic profile of aptamers. This study investigates the effect of Cys34 site-selective covalent attachment of a factor IXa anticoagulant aptamer on aptamer functionality and human FcRn (hFcRn) engagement using recombinant human albumin (rHA) of either a wild type (WT) or an engineered human FcRn high binding variant (HB). Albumin-aptamer conjugates, connected covalently through a heterobifunctional succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate linker, were successfully prepared and purified by high performance liquid chromatography as confirmed by gel electrophoresis band-shift analysis and matrix-assisted laser desorption/ionization time of flight. Minimal reduction (∼25%) in activity of WT-linked aptamer to that of aptamer alone was found using an anticoagulant activity assay measuring temporal levels of activated partial thrombin. Covalent albumin-aptamer conjugation, however, substantially compromized binding to hFcRn, to 10% affinity of that of non-conjugated WT, determined by biolayer interferometry. Binding could be rescued by aptamer conjugation to recombinant albumin engineered for higher FcRn affinity (HB) that exhibited an 8-fold affinity compared to WT alone. This work describes a novel albumin-based aptamer delivery system whose hFcRn binding can be increased using a HB engineered albumin.

  14. Therapeutic Fc-fusion proteins and peptides as successful alternatives to antibodies.

    Science.gov (United States)

    Beck, Alain; Reichert, Janice M

    2011-01-01

    Therapeutic antibodies have captured substantial attention due to the relatively high rate at which these products reach marketing approval, and the subsequent commercial success they frequently achieve. In the 2000s, a total of 20 antibodies (18 full-length IgG and 2 Fab) were approved by the Food and Drug Administration (FDA) or European Medicines Agency (EMA). In the 2010s to date, an additional 3 antibodies (denosumab, belimumab, ipilimumab) have been approved and one antibody-drug conjugate (brentuximab vedotin) is undergoing regulatory review and may be approved in the US by August 30, 2011. However, a less heralded group of antibody-based therapeutics comprising proteins or peptides fused with an Fc is following the success of classical antibodies.

  15. Targeting human prostate cancer with In-111-labeled D2B IgG, F(ab ')(2) and Fab fragments in nude mice with PSMA-expressing xenografts

    NARCIS (Netherlands)

    Lutje, Susanne; van Rij, Catharina M.; Franssen, Gerben M.; Fracasso, Giulio; Helfrich, Wijnand; Eek, Annemarie; Oyen, Wim J.; Colombatti, Marco; Boerman, Otto C.

    2014-01-01

    D2B is a new monoclonal antibody directed against an extracellular domain of prostate-specific membrane antigen (PSMA), which is overexpressed in prostate cancer. The potential of D2B IgG, and F(ab)(2) and Fab fragments of this antibody for targeting prostate cancer was determined in mice bearing

  16. Targeting human prostate cancer with (111) In-labeled D2B IgG, F(ab')2 and Fab fragments in nude mice with PSMA-expressing xenografts

    NARCIS (Netherlands)

    Lutje, S.; Rij, C.M. van; Franssen, G.M.; Fracasso, G.; Helfrich, W.; Eek, A.; Oyen, W.J.G.; Colombatti, M.; Boerman, O.C.

    2015-01-01

    D2B is a new monoclonal antibody directed against an extracellular domain of prostate-specific membrane antigen (PSMA), which is overexpressed in prostate cancer. The potential of D2B IgG, and F(ab')2 and Fab fragments of this antibody for targeting prostate cancer was determined in mice bearing

  17. Oxidation of M252 but not M428 in hu-IgG1 is responsible for decreased binding to and activation of hu-FcγRIIa (His131).

    Science.gov (United States)

    Cymer, Florian; Thomann, Marco; Wegele, Harald; Avenal, Cecile; Schlothauer, Tilman; Gygax, Daniel; Beck, Hermann

    2017-11-01

    Oxidation of monoclonal therapeutic antibodies (mAbs) can affect binding to Fc-receptors and potentially influence pharmacokinetics or effector functions like e.g. antibody dependent cellular phagocytosis (ADCP). Recently, it has been demonstrated that binding to FcγRIIa (H131) is affected by methionine oxidation of the Fc-portion but it is currently unknown which methionine is responsible for decreased binding. We separated an oxidized IgG1 monoclonal antibody based on the oxidation state of methionine 252 and analyzed fractionated material in receptor binding experiments as well as in functional (cell-based) assays. Although the unfractionated mixture demonstrated weaker interaction/activation of the receptor, differently oxidized isolated subspecies can lead both to stronger as well as weaker binding and activation of the histidine variant of FcγRIIa. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Optimal football strategies: AC Milan versus FC Barcelona

    OpenAIRE

    Papahristodoulou, Christos

    2012-01-01

    In a recent UEFA Champions League game between AC Milan and FC Barcelona, played in Italy (final score 2-3), the collected match statistics, classified into four offensive and two defensive strategies, were in favour of FC Barcelona (by 13 versus 8 points). The aim of this paper is to examine to what extent the optimal game strategies derived from some deterministic, possibilistic, stochastic and fuzzy LP models would improve the payoff of AC Milan at the cost of FC Barcelona.

  19. Herpes simplex virus immunoglobulin G Fc receptor activity depends on a complex of two viral glycoproteins, gE and gI

    International Nuclear Information System (INIS)

    Johnson, D.C.; Ligas, M.W.; Frame, M.C.; Cross, A.M.; Stow, N.D.

    1988-01-01

    Evidence was recently presented that herpes simplex virus type 1 (HSV-1) immunoglobulin G (IgG) Fc receptors are composed of a complex containing a previously described glycoprotein, gE, and a novel virus-induced polypeptide, provisionally named g70. Using a monoclonal antibody designated 3104, which recognizes g70, in conjunction with antipeptide sera and virus mutants unable to express g70 or gE, the authors have mapped the gene encoding g70 to the US7 open reading frame of HSV-1 adjacent to the gE gene. Therefore, g70 appears to be identical to a recently described polypeptide which was named gI. Under mildly denaturing conditions, monoclonal antibody 3104 precipitated both gI and gE from extracts of HSV-1-infected cells. In addition, rabbit IgG precipitated the gE-gI complex from extracts of cells transfected with a fragment of HSV-1 DNA containing the gI, gE, and US9 genes. Cells infected with mutant viruses which were unable to express gE or gI did not bind radiolabeled IgG; however, cells coinfected with two viruses, one unable to express gE and the other unable to express gI, bound levels of IgG approaching those observed with wild-type viruses. These results further support the hypothesis that gE and gI form a complex which binds IgG by the Fc domain and that neither polypeptide alone can bind IgG

  20. Selective localization of IgG from cerebrospinal fluid to brain parenchyma

    DEFF Research Database (Denmark)

    Mørch, Marlene Thorsen; Forsberg Sørensen, Sofie; Khorooshi, Reza M. H.

    2018-01-01

    the cerebrospinal fluid and induce subpial and periventricular NMO-like lesions and blood-brain barrier breakdown, in a complement-dependent manner. To investigate how IgG trafficking from cerebrospinal fluid to brain parenchyma can be influenced by injury. IgG from healthy donors was intrathecally injected...... into the cerebrospinal fluid via cisterna magna at 1, 2, 4, or 7 days after a distal stereotactic sterile needle insertion to the striatum. Antibody deposition, detected by staining for human IgG, peaked 1 day after the intrathecal injection and was selectively seen close to the needle insertion. When NMO...

  1. IgG4-related prostatitis progressed from localized IgG4-related lymphadenopathy.

    Science.gov (United States)

    Li, Dujuan; Kan, Yunzhen; Fu, Fangfang; Wang, Shuhuan; Shi, Ligang; Liu, Jie; Kong, Lingfei

    2015-01-01

    Immunoglobulin G4-related disease (IgG4-RD) is a recently described inflammatory disease involving multiple organs. Prostate involvement with IgG4-RD is very rare. In this report, we describe a case of IgG4-related prostatitis progressed from localized IgG4-related lymphadenopathy. This patient was present with urine retention symptoms. MRI and CT examination revealed the prostatic enlargement and the multiple lymphadenopathy. Serum IgG4 levels were elevated. Prostatic tissue samples resected both this time and less than 1 year earlier showed the same histological type of prostatitis with histopathologic and immunohistochemical findings characteristic of IgG4-RD. The right submandibular lymph nodes excised 2 years earlier were eventually proven to be follicular hyperplasia-type IgG4-related lymphadenopathy. This is the first case of IgG4-RD that began as localized IgG4-related lymphadenopathy and progressed into a systemic disease involving prostate and multiple lymph nodes. This patient showed a good response to steroid therapy. This leads us to advocate a novel pathogenesis of prostatitis, and a novel therapeutic approach against prostatitis. Pathologists and urologists should consider this disease entity in the patients with elevated serum IgG4 levels and the symptoms of prostatic hyperplasia to avoid ineffective medical or unnecessary surgical treatment.

  2. Rab20 regulates phagosome maturation in RAW264 macrophages during Fc gamma receptor-mediated phagocytosis.

    Directory of Open Access Journals (Sweden)

    Youhei Egami

    Full Text Available Rab20, a member of the Rab GTPase family, is known to be involved in membrane trafficking, however its implication in FcγR-mediated phagocytosis is unclear. We examined the spatiotemporal localization of Rab20 during phagocytosis of IgG-opsonized erythrocytes (IgG-Es in RAW264 macrophages. By the live-cell imaging of fluorescent protein-fused Rab20, it was shown that Rab20 was transiently associated with the phagosomal membranes. During the early stage of phagosome formation, Rab20 was not localized on the membranes of phagocytic cups, but was gradually recruited to the newly formed phagosomes. Although Rab20 was colocalized with Rab5 to some extent, the association of Rab20 with the phagosomes persisted even after the loss of Rab5 from the phagosomal membranes. Then, Rab20 was colocalized with Rab7 and Lamp1, late endosomal/lysosomal markers, on the internalized phagosomes. Moreover, our analysis of Rab20 mutant expression revealed that the maturation of phagosomes was significantly delayed in cells expressing the GDP-bound mutant Rab20-T19N. These data suggest that Rab20 is an important component of phagosome and regulates the phagosome maturation during FcγR-mediated phagocytosis.

  3. Hubungan Polimorfisme Gen FcγRIIA dengan Densitas P. falciparum dan Efikasi Dihidroartemisinin-Piperakuin

    Directory of Open Access Journals (Sweden)

    Sylvia Sance Marantina

    2016-06-01

    Full Text Available Dimorfisme FcγRlla memiliki keterkaitan dengan kemampuan inang dalam mengeliminasi parasit malaria sehingga perlu dilakukan penelitian untuk mengetahui polimorfisme alel FcγRlla dari populasi di daerah endemis malaria di Indonesia agar dapat diketahui peran imunitas dalam mengeliminasi parasit malaria. Sebanyak 120 sampel dried blood spot (DBS malaria falsifarum yang diperoleh dari studi efikasi obat DHP di lima wilayah di Indonesia dianalisis dengan polymerase chain reaction (PCR dan sekuensing untuk melihat varian alel FcγRIIa-131 serta hubungannya dengan densitas parasit dan efikasi dihidroartemisinin-piperakuin. Analisis gen FcγRIIa menunjukkan bahwa genotip RH memiliki frekuensi paling tinggi (50,8% dibandingkan RR (17,5% dan HH (31,7%. Alel R131 gen FcγRIIa menunjukkan efek protektif terhadap high density parasitemia/HDP (>5000 parasit/μL; odds ratio [OR]= 0,133, 95% confidence interval [CI]= 0,053–0,334, p< 0,001 dan berhubungan dengan keberadaan gametosit yang lebih lama pada inang (>72 jam; relative risk [RR]= 1,571, 95% confidence interval [CI]= 1,005–2,456, p= 0,090. Kata Kunci: malaria falsiparum, dihidroartemisinin-piperakuin, K13, FcγRIIa, efikasi obat Polymorphism of Human FcγRIIa and Its Association with P. falciparum Density and Efficacy of Dihydroartemisinin- Piperaquine Abstract FcγRlla dimorphism has been related to the ability of the host to eliminate malaria parasite so it is necessary to investigate the allele polymorphism FcγRlla of population in malaria-endemic areas in Indonesia in order to know the role of immunity in eliminating malaria parasite. A total of 120 samples of Dried Blood Spot (DBS falciparum malaria acquired from DHP drug efficacy studies in 5 regions in Indonesia were analyzed by Polymerase Chain Reaction (PCR and sequencing, to look at variants of FcγRIIa-131 allele and its Association with Parasite DensityandEfficacy ofDihydroartemisinin- Piperaquine. The FcγRIIa gene analysis indicated

  4. A freeze dried kit formulation for the preparation of {sup 99m} Tc labelled human polyclonal IgG for the detection of infection and inflammation; Desarrollo del nucleo equipo {sup 99m} Tc-IgG humana para la deteccion `In vivo` de procesos inflamatorios

    Energy Technology Data Exchange (ETDEWEB)

    Pedraza L, M

    1996-11-01

    A freeze dried kit formulation for the preparation of {sup 99m}Tc-labelled human polyclonal IgG for the detection of infection and inflammation employing direct methods for protein labeling was developed. The method comprises reduction of intrinsic disulphide bridges within the antibody molecule by the use of the reductant 2-mercaptoethanol. Following a subsequent purification, the resulting reduced antibody is labeled via Sn{sup 2+} reduction of pertechnetate in the presence of a weak competing ligand ethane-1-hydroxy-1,1-diphosphonate (EHDP). High labeling efficiencies (>90%) were obtained with high in vitro stability and without effect upon antibody immunoreactivity. Methods of analysis were also established permitting identification of radiochemical impurities which may be present in radiopharmaceutical solution. {sup 99m} Tc-polyclonal IgG prepared by the kit method was evaluated for scintigraphic localization of inflammatory lesions and abscesses in rabbits. Data demonstrated that the {sup 99m} Tc-polyclonal IgG after kit-reconstitution shows excellent stability and is an effective imaging agent of infection and/or inflammation. (Author).

  5. Optimization on Fc for Improvement of Stability and Aggregation Resistance.

    Science.gov (United States)

    Chen, Xiaobo; Zeng, Fang; Huang, Tao; Cheng, Liang; Liu, Huan; Gong, Rui

    2016-01-01

    Fc-based therapeutics including therapeutic full-size monoclonal antibodies (mAbs) and Fcfusion proteins represent fastest-growing market in biopharmaceutical industrial. However, one major challenge during development of Fc-based therapeutics is how to maintain their efficacy in clinic use. Many factors may lead to failure in final marketing. For example, the stability and aggregation resistance might not be high enough for bearing the disadvantages during fermentation, purification, formulation, storage, shipment and other steps in manufacture and sale. Low stability and high aggregation tendency lead to decreased bioactivity and increased risk of immunogenicity resulting in serious side effect. Because Fc is one of the major parts in monoclonal antibodies and Fc-fusion proteins, engineering of Fc to increase its stability and reduce or eliminate aggregation due to incorrect association are of great importance and could further extend the potential of Fc-based therapeutics. Lots of studies focus on Fc optimization for better physical and chemical characteristics and function by structured-based computer-aid rational design, high-throughput screening expression system selection and other methods. The identification of optimized Fc mutants increases the clinic potential of currently existed therapeutics mAbs and Fc-fusion proteins, and accelerates the development of new Fc-based therapeutics. Here we provide an overview of the related field, and discuss recent advances and future directions in optimization of Fc-based therapeutics with modified stability and aggregation resistance. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  6. Humoral immunity provides resident intestinal eosinophils access to luminal antigen via eosinophil-expressed low affinity Fc gamma receptors

    Science.gov (United States)

    Smith, Kalmia M.; Rahman, Raiann S.; Spencer, Lisa A.

    2016-01-01

    Eosinophils are native to the healthy gastrointestinal tract, and are associated with inflammatory diseases likely triggered by exposure to food allergens (e.g. food allergies and eosinophilic gastrointestinal disorders). In models of allergic respiratory diseases and in vitro studies, direct antigen engagement elicits eosinophil effector functions including degranulation and antigen presentation. However, it was not known whether intestinal tissue eosinophils that are separated from luminal food antigens by a columnar epithelium might similarly engage food antigens. Using an intestinal ligated loop model in mice, here we determined that resident intestinal eosinophils acquire antigen from the lumen of antigen-sensitized but not naïve mice in vivo. Antigen acquisition was immunoglobulin-dependent; intestinal eosinophils were unable to acquire antigen in sensitized immunoglobulin-deficient mice, and passive immunization with immune serum or antigen-specific IgG was sufficient to enable intestinal eosinophils in otherwise naïve mice to acquire antigen in vivo. Intestinal eosinophils expressed low affinity IgG receptors, and the activating receptor FcγRIII was necessary for immunoglobulin-mediated acquisition of antigens by isolated intestinal eosinophils in vitro. Our combined data suggest that intestinal eosinophils acquire lumen-derived food antigens in sensitized mice via FcγRIII antigen focusing, and may therefore participate in antigen-driven secondary immune responses to oral antigens. PMID:27683752

  7. Thermal decomposition of FC(O)OCH3 and FC(O)OCH2CH3.

    Science.gov (United States)

    Berasategui, M; Argüello, G A; Burgos Paci, M A

    2018-05-09

    The thermal decomposition of methyl and ethyl formates has been extensively studied due to their importance in the oxidation of several fuels, pesticidal properties and their presence in interstellar space. We hitherto present the study of the thermal decomposition of methyl and ethyl fluoroformates, which could help in the elucidation of the reaction mechanisms. The reaction mechanisms were studied using FTIR spectroscopy in the temperature range of 453-733 K in the presence of different pressures of N2 as bath gas. For FC(O)OCH3 two different channels were observed; the unimolecular decomposition which is favored at higher temperatures and has a rate constant kFC(O)OCH3 = (5.3 ± 0.5) × 1015 exp[-(246 ± 10 kJ mol-1/RT)] (in units of s-1) and a bimolecular channel with a rate constant kFC(O)OCH3 = (1.6 ± 0.5) × 1011 exp[-(148 ± 10 kJ mol-1/RT)] (in units of s-1 (mol L)-1). However for ethyl formate, only direct elimination of CO2, HF and ethylene operates. The rate constants of the homogeneous first-order process fit the Arrhenius equation kFC(O)OCH2CH3 = (2.06 ± 0.09) × 1013 exp[-(169 ± 6 kJ mol-1/RT)] (in units of s-1). The difference between the mechanisms of the two fluoroformates relies on the stabilization of a six-centered transition state that only exists for ethyl formate. First principles calculations for the different channels were carried out to understand the dynamics of the decomposition.

  8. AlphaScreen-based homogeneous assay using a pair of 25-residue artificial proteins for high-throughput analysis of non-native IgG.

    Science.gov (United States)

    Senga, Yukako; Imamura, Hiroshi; Miyafusa, Takamitsu; Watanabe, Hideki; Honda, Shinya

    2017-09-29

    Therapeutic IgG becomes unstable under various stresses in the manufacturing process. The resulting non-native IgG molecules tend to associate with each other and form aggregates. Because such aggregates not only decrease the pharmacological effect but also become a potential risk factor for immunogenicity, rapid analysis of aggregation is required for quality control of therapeutic IgG. In this study, we developed a homogeneous assay using AlphaScreen and AF.2A1. AF.2A1 is a 25-residue artificial protein that binds specifically to non-native IgG generated under chemical and physical stresses. This assay is performed in a short period of time. Our results show that AF.2A1-AlphaScreen may be used to evaluate the various types of IgG, as AF.2A1 recognizes the non-native structure in the constant region (Fc region) of IgG. The assay was effective for detection of non-native IgG, with particle size up to ca. 500 nm, generated under acid, heat, and stirring conditions. In addition, this technique is suitable for analyzing non-native IgG in CHO cell culture supernatant and mixed with large amounts of native IgG. These results indicate the potential of AF.2A1-AlphaScreen to be used as a high-throughput evaluation method for process monitoring as well as quality testing in the manufacturing of therapeutic IgG.

  9. Development of a polyclonal anti-dugong immunoglobulin G (IgG) antibody with evaluation of total plasma IgG in a living dugong (Dugong dugon) population.

    Science.gov (United States)

    Wong, Arthur; Lanyon, Janet M; McKee, Sara J; Linedale, Richard; Woolford, Lucy; Long, Trevor; Leggatt, Graham R

    2018-06-01

    Species-specific antibodies (Ab) for the measurement of immunoglobulins (Ig) are valuable tools for determining the humoral immune status of threatened and endangered wildlife species such as dugongs. However, no studies have reported antibody reagents against dugong immunoglobulin. The object of this study was to develop an Ab with specificity for dugong IgG and apply this tool to survey total IgG levels in plasma samples from a live wild population of dugongs in southern Queensland, Australia. Dugong IgG was isolated from plasma by protein A/G column chromatography and a polyclonal antiserum was successfully raised against the dugong IgG through immunization of mice. The anti-dugong antiserum was reactive with dugong serum but not immunoglobulin from other species such as rats and humans. When tested against a panel of dugong plasma samples, relative IgG levels from dugongs (n = 116) showed biologically relevant relationships with pregnancy status and a principal component of Body Mass Index (BMI)/globulin/fecal glucocorticosteroid (chronic stress) levels combined, which together accounted for 9.2% of the variation in total Ig levels. Together these data suggest that dugongs show variation in total IgG and that this correlates with some physiological parameters of dugong health. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Igg Subclasses Targeting the Flagella of Salmonella enterica Serovar Typhimurium Can Mediate Phagocytosis and Bacterial Killing

    Science.gov (United States)

    Goh, Yun Shan; Armour, Kathryn L; Clark, Michael R; Grant, Andrew J; Mastroeni, Pietro

    2016-01-01

    Invasive non-typhoidal Salmonella are a common cause of invasive disease in immuno-compromised individuals and in children. Multi-drug resistance poses challenges to disease control, with a critical need for effective vaccines. Flagellin is an attractive vaccine candidate due to surface exposure and high epitope copy number, but its potential as a target for opsonophacytic antibodies is unclear. We examined the effect of targeting flagella with different classes of IgG on the interaction between Salmonella Typhimurium and a human phagocyte-like cell line, THP-1. We tagged the FliC flagellar protein with a foreign CD52 mimotope (TSSPSAD) and bacteria were opsonized with a panel of humanised CD52 antibodies with the same antigen-binding V-region, but different constant regions. We found that IgG binding to flagella increases bacterial phagocytosis and reduces viable intracellular bacterial numbers. Opsonisation with IgG3, followed by IgG1, IgG4, and IgG2, resulted in the highest level of bacterial uptake and in the highest reduction in the intracellular load of viable bacteria. Taken together, our data provide proof-of-principle evidence that targeting flagella with antibodies can increase the antibacterial function of host cells, with IgG3 being the most potent subclass. These data will assist the rational design of urgently needed, optimised vaccines against iNTS disease. PMID:27366588

  11. Fc-based delivery system enhances immunogenicity of a tuberculosis subunit vaccine candidate consisting of the ESAT-6:CFP-10 complex.

    Science.gov (United States)

    Farsiani, Hadi; Mosavat, Arman; Soleimanpour, Saman; Sadeghian, Hamid; Akbari Eydgahi, Mohammad Reza; Ghazvini, Kiarash; Sankian, Mojtaba; Aryan, Ehsan; Jamehdar, Saeid Amel; Rezaee, Seyed Abdolrahim

    2016-06-21

    Tuberculosis (TB) remains a major global health threat despite chemotherapy and Bacilli Calmette-Guérin (BCG) vaccination. Therefore, a safer and more effective vaccine against TB is urgently needed. This study evaluated the immunogenicity of a recombinant fusion protein consisting of early secreted antigenic target protein 6 kDa (ESAT-6), culture filtrate protein 10 kDa (CFP-10) and the Fc-domain of mouse IgG2a as a novel subunit vaccine. The recombinant expression vectors (pPICZαA-ESAT-6:CFP-10:Fcγ2a and pPICZαA-ESAT-6:CFP-10:His) were transferred into Pichia pastoris. After SDS-PAGE and immunoblotting, the immunogenicity of the recombinant proteins was evaluated in mice. When both recombinant proteins (ESAT-6:CFP-10:Fcγ2a and ESAT-6:CFP-10:His) were used for vaccination, Th1-type cellular responses were induced producing high levels of IFN-γ and IL-12. However, the Fc-tagged recombinant protein induced more effective Th1-type cellular responses with a small increase in IL-4 as compared to the BCG and ESAT-6:CFP-10:His groups. Moreover, mice primed with BCG and then supplemented with ESAT-6:CFP-10:Fcγ2a produced the highest levels of IFN-γ and IL-12 in immunized groups. The findings indicate that when Fcγ2a is fused to the ESAT-6:CFP-10 complex, as a delivery vehicle, there could be an increase in the immunogenicity of this type of subunit vaccine. Therefore, additional investigations are necessary for the development of appropriate Fc-based tuberculosis vaccines.

  12. Maternal immunization with ovalbumin prevents neonatal allergy development and up-regulates inhibitory receptor FcγRIIB expression on B cells

    Directory of Open Access Journals (Sweden)

    Duarte Alberto JS

    2010-03-01

    Full Text Available Abstract Background Preconception allergen immunization prevents neonatal allergen sensitization in mice by a complex interaction between regulatory cells/factors and antibodies. The present study assessed the influence of maternal immunization with ovalbumin (OVA on the immune response of 3 day-old and 3 week-old offspring immunized or non-immunized with OVA and evaluated the effect of IgG treatment during fetal development or neonatal period. Results Maternal immunization with OVA showed increased levels of FcγRIIb expression in splenic B cells of neonates, which were maintained for up to 3 weeks and not affected by additional postnatal OVA immunization. Maternal immunization also exerted a down-modulatory effect on both IL-4 and IFN-γ-secreting T cells and IL-4 and IL-12- secreting B cells. Furthermore, immunized neonates from immunized mothers showed a marked inhibition of antigen-specifc IgE Ab production and lowered Th2/Th1 cytokine levels, whereas displaying enhanced FcγRIIb expression on B cells. These offspring also showed reduced antigen-specific proliferative response and lowered B cell responsiveness. Moreover, in vitro evaluation revealed an impairment of B cell activation upon engagement of B cell antigen receptor by IgG from OVA-immunized mice. Finally, in vivo IgG transference during pregnancy or breastfeeding revealed that maternal Ab transference was able to increase regulatory cytokines, such as IL-10, in the prenatal stage; yet only the postnatal treatment prevented neonatal sensitization. None of the IgG treatments induced immunological changes in the offspring, as it was observed for those from OVA-immunized mothers. Conclusion Maternal immunization upregulates the inhibitory FcγRIIb expression on offspring B cells, avoiding skewed Th2 response and development of allergy. These findings contribute to the advancement of prophylactic strategies to prevent allergic diseases in early life.

  13. Construction of a bimolecular fluorescence complementation (BiFC ...

    African Journals Online (AJOL)

    Protein–protein interactions are essential for signal transduction in cells. Bimolecular fluorescence complementation (BiFC) is a novel technology that utilises green fluorescent proteins to visualize protein–protein interactions and subcellular protein localisation. BiFC based on pSATN vectors are a good system for ...

  14. Facile method for the site-specific, covalent attachment of full-length IgG onto nanoparticles.

    Science.gov (United States)

    Hui, James Zhe; Al Zaki, Ajlan; Cheng, Zhiliang; Popik, Vladimir; Zhang, Hongtao; Luning Prak, Eline T; Tsourkas, Andrew

    2014-08-27

    Antibodies, most commonly IgGs, have been widely used as targeting ligands in research and therapeutic applications due to their wide array of targets, high specificity and proven efficacy. Many of these applications require antibodies to be conjugated onto surfaces (e.g. nanoparticles and microplates); however, most conventional bioconjugation techniques exhibit low crosslinking efficiencies, reduced functionality due to non-site-specific labeling and random surface orientation, and/or require protein engineering (e.g. cysteine handles), which can be technically challenging. To overcome these limitations, we have recombinantly expressed Protein Z, which binds the Fc region of IgG, with an UV active non-natural amino acid benzoylphenyalanine (BPA) within its binding domain. Upon exposure to long wavelength UV light, the BPA is activated and forms a covalent link between the Protein Z and the bound Fc region of IgG. This technology was combined with expressed protein ligation (EPL), which allowed for the introduction of a fluorophore and click chemistry-compatible azide group onto the C-terminus of Protein Z during the recombinant protein purification step. This enabled the crosslinked-Protein Z-IgG complexes to be efficiently and site-specifically attached to aza-dibenzocyclooctyne-modified nanoparticles, via copper-free click chemistry. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Targeting human prostate cancer with 111In-labeled D2B IgG, F(ab')2 and Fab fragments in nude mice with PSMA-expressing xenografts.

    Science.gov (United States)

    Lütje, Susanne; van Rij, Catharina M; Franssen, Gerben M; Fracasso, Giulio; Helfrich, Wijnand; Eek, Annemarie; Oyen, Wim J; Colombatti, Marco; Boerman, Otto C

    2015-01-01

    D2B is a new monoclonal antibody directed against an extracellular domain of prostate-specific membrane antigen (PSMA), which is overexpressed in prostate cancer. The potential of D2B IgG, and F(ab')2 and Fab fragments of this antibody for targeting prostate cancer was determined in mice bearing subcutaneous prostate cancer xenografts. The optimal time point for imaging was determined in biodistribution and microSPECT imaging studies with (111)In-D2B IgG, (111)In-capromab pendetide, (111)In-D2B F(ab')2 and (111)In-D2B Fab fragments in mice with PSMA-expressing LNCaP and PSMA-negative PC3 tumors at several time points after injection. All (111)In-labeled antibody formats specifically accumulated in the LNCaP tumors, with highest uptake of (111)In-D2B IgG and (111)In-capromab pendetide at 168 h p.i. (94.8 ± 19.2% injected dose per gram (ID/g) and 16.7 ± 2.2% ID/g, respectively), whereas uptake of (111)In-D2B F(ab')2 and (111)In-D2B Fab fragments peaked at 24 h p.i. (12.1 ± 3.0% ID/g and 15.1 ± 2.9% ID/g, respectively). Maximum LNCaP tumor-to-blood ratios were 13.0 ± 2.3 (168 h p.i.), 6.2 ± 0.7 (24 h p.i.), 23.0 ± 4.0 (24 h p.i.) and 4.5 ± 0.6 (168 h p.i.) for (111)In-D2B IgG, (111)In-F(ab')2, (111)In-Fab and (111)In-capromab pendetide, respectively. LNCaP tumors were clearly visualized with microSPECT with all antibody formats. This study demonstrates the feasibility of D2B IgG, F(ab')2 and Fab fragments for targeting PSMA-expressing prostate cancer xenografts. Copyright © 2014 John Wiley & Sons, Ltd.

  16. The production of KIR-Fc fusion proteins and their use in a multiplex HLA class I binding assay.

    Science.gov (United States)

    Hilton, Hugo G; Moesta, Achim K; Guethlein, Lisbeth A; Blokhuis, Jeroen; Parham, Peter; Norman, Paul J

    2015-10-01

    Soluble recombinant proteins that comprise the extracellular part of a surface expressed receptor attached to the Fc region of an IgG antibody have facilitated the determination of ligand specificity for an array of immune system receptors. Among such receptors is the family of killer cell immunoglobulin-like receptors (KIR) that recognize HLA class I ligands. These receptors, expressed on natural killer (NK) cells and T cells, play important roles in both immune defense and placental development in early pregnancy. Here we describe a method for the production of two domain KIR-Fc fusion proteins using baculovirus infected insect cells. This method is more scalable than traditional mammalian cell expression systems and produces efficiently folded proteins that carry posttranslational modifications found in native KIR. We also describe a multiplex binding assay using the Luminex platform that determines the avidity and specificity of two domain KIR-Fc for a panel of microbeads, each coated with one of 97 HLA class I allotypes. This assay is simple to perform, and represents a major improvement over the assays used previously, which were limited in the number of KIR and HLA class I combinations that could be assayed at any one time. The results obtained from this assay can be used to predict the response of NK cell and T cells when their KIR recognize HLA class I. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Immunochemical characteristics of IgG4 antibodies

    NARCIS (Netherlands)

    van der Zee, J. S.; Aalberse, R. C.

    1988-01-01

    Although a small part of the IgG4 subclass probably can bind to basophils (and mast cells), IgG4 antibodies usually do not behave as anaphylactic antibodies. Therefore, detection of IgG4 antibodies in serum is not a suitable in vitro assay for IgG-S-TS activity. Furthermore, differences between IgG4

  18. Neuromyelitis optica IgG in the cerebrospinal fluid induces astrocytopathy in optic nerve

    DEFF Research Database (Denmark)

    Soelberg, Kerstin; Lillevang, Søren Thue; Mørch, Marlene

    (anti-CD59a). A total of five mice received AQP4-IgG + C + anti-CD59a, four mice received normal-IgG + C + anti-CD59a, four mice received AQP4-IgG+ C and one normal-IgG + C. Mice were killed four days later. The optic nerves were isolated and fixed in paraformaldehyde. Paraffin embedded optic nerves...... was coincident with deposition of complement. Histopathological lesions were markedly enhanced with extensive/long-segment astrocytopathy of optic nerve and optic chiasm involvement in AQP4- IgG+ C + anti-CD59a treated mice. Such pathology was not seen in mice receiving normal human IgG, C and anti-CD59a...

  19. 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

  20. On the role of IgG4 in inflammatory conditions: lessons for IgG4-related disease

    NARCIS (Netherlands)

    Trampert, David C.; Hubers, Lowiek M.; van de Graaf, Stan F. J.; Beuers, Ulrich

    2017-01-01

    The pathophysiology of immunoglobulin G4-related disease (IgG4-RD) and its most common manifestations, IgG4-associated (sclerosing) cholangitis and autoimmune pancreatitis, remains largely unknown, but IgG4 is presumably involved. IgG4 is a promiscuous antibody, which could be directly pathogenic,

  1. IgG4 related sclerosing mastitis: expanding the morphological spectrum of IgG4 related diseases.

    Science.gov (United States)

    Chougule, Abhijit; Bal, Amanjit; Das, Ashim; Singh, Gurpreet

    2015-01-01

    IgG4 related disease (IgG4RD) is a recently recognised condition characterised by mass forming lesions associated with storiform fibrosis, obliterative phlebitis, lymphoplasmacytic infiltrate rich in IgG4 positive plasma cells and elevated serum IgG4 levels. Although rare, mammary involvement has been reported as IgG4 related sclerosing mastitis, the morphological counterpart of a growing family of IgG4 related diseases. A total of 17 cases belonging to mass forming benign inflammatory breast lesions such as plasma cell mastitis, granulomatous lobular mastitis, non-specific mastitis and inflammatory pseudotumour were investigated as a possible member of IgG4 related sclerosing mastitis. Clinical, radiological, histopathological and immunohistochemistry findings were noted in all cases. Cases diagnosed as inflammatory pseudotumour showed all the histopathological features of IgG4RD along with increased number of IgG4 positive plasma cells and IgG4/IgG ratio >40%. However, only a few IgG4 positive cells were seen in plasma cell mastitis, granulomatous lobular mastitis and non-specific mastitis cases. These cases also did not fulfill the morphological criteria for the diagnosis of IgG4 related diseases. IgG4RD should be excluded in plasma cell rich lesions diagnosed on core biopsies by IgG4 immunostaining. This can avoid unnecessary surgery as IgG4 related diseases respond to simple and effective steroid treatment.

  2. Generation and characterization of a human-mouse chimeric high-affinity antibody that detects the DYKDDDDK FLAG peptide.

    Science.gov (United States)

    Ikeda, Koki; Koga, Tomoaki; Sasaki, Fumiyuki; Ueno, Ayumi; Saeki, Kazuko; Okuno, Toshiaki; Yokomizo, Takehiko

    2017-05-13

    DYKDDDDK peptide (FLAG) is a useful tool for investigating the function and localization of proteins whose antibodies (Abs) are not available. We recently established a high-affinity monoclonal antibody (mAb) for FLAG (clone 2H8). The 2H8 Ab is highly sensitive for detecting FLAG-tagged proteins by flowcytometry and immunoprecipitation, but it can yield nonspecific signals in immunohistochemistry of mouse tissues because it is of mouse origin. In this study, we reduced nonspecific signals by generating a chimeric 2H8 Ab with Fc fragments derived from human immunoglobulin. We fused a 5' terminal cDNA fragments for the Fab region of 2H8 mAb with 3' terminal cDNA fragments for Fc region of human IgG1. We transfected both chimeric plasmids and purified the resulting human-mouse chimeric 2H8. The chimeric 2H8 Ab successfully detected FLAG-tagged proteins in flowcytometry with anti-human IgG secondary Ab with comparable sensitivity to 2H8 mAb. Importantly, chimeric 2H8 detected specific FLAG peptide signals without nonspecific signals in immunohistochemical analysis with mouse tissues. This human-mouse chimeric high-affinity anti-FLAG Ab will prove useful for future immunohistochemical analysis of mouse tissues. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Altered glycosylation of complexed native IgG molecules is associated with disease activity of systemic lupus erythematosus.

    Science.gov (United States)

    Sjöwall, C; Zapf, J; von Löhneysen, S; Magorivska, I; Biermann, M; Janko, C; Winkler, S; Bilyy, R; Schett, G; Herrmann, M; Muñoz, L E

    2015-05-01

    In addition to the redundancy of the receptors for the Fc portion of immunoglobulins, glycans result in potential ligands for a plethora of lectin receptors found in immune effector cells. Here we analysed the exposure of glycans containing fucosyl residues and the fucosylated tri-mannose N-type core by complexed native IgG in longitudinal serum samples of well-characterized patients with systemic lupus erythematosus. Consecutive serum samples of a cohort of 15 patients with systemic lupus erythematosus during periods of increased disease activity and remission were analysed. All patients fulfilled the 1982 American College of Rheumatology classification criteria. Sera of 15 sex- and age-matched normal healthy blood donors served as controls. The levels and type of glycosylation of complexed random IgG was measured with lectin enzyme-immunosorbent assays. After specifically gathering IgG complexes from sera, biotinylated lectins Aleuria aurantia lectin and Lens culinaris agglutinin were employed to detect IgG-associated fucosyl residues and the fucosylated tri-mannose N-glycan core, respectively. In sandwich-ELISAs, IgG-associated IgM, IgA, C1q, C3c and C-reactive protein (CRP) were detected as candidates for IgG immune complex constituents. We studied associations of the glycan of complexed IgG and disease activity according to the physician's global assessment of disease activity and the systemic lupus erythematosus disease activity index 2000 documented at the moment of blood taking. Our results showed significantly higher levels of Aleuria aurantia lectin and Lens culinaris agglutinin binding sites exposed on IgG complexes of patients with systemic lupus erythematosus than on those of normal healthy blood donors. Disease activity in systemic lupus erythematosus correlated with higher exposure of Aleuria aurantia lectin-reactive fucosyl residues by immobilized IgG complexes. Top levels of Aleuria aurantia lectin-reactivity were found in samples taken during the

  4. The antigen-binding fragment of human gamma immunoglobulin prevents amyloid β-peptide folding into β-sheet to form oligomers

    Science.gov (United States)

    Valls-Comamala, Victòria; Guivernau, Biuse; Bonet, Jaume; Puig, Marta; Perálvarez-Marín, Alex; Palomer, Ernest; Fernàndez-Busquets, Xavier; Altafaj, Xavier; Tajes, Marta; Puig-Pijoan, Albert; Vicente, Rubén; Oliva, Baldomero; Muñoz, Francisco J.

    2017-01-01

    The amyloid beta-peptide (Aβ) plays a leading role in Alzheimer's disease (AD) physiopathology. Even though monomeric forms of Aβ are harmless to cells, Aβ can aggregate into β-sheet oligomers and fibrils, which are both neurotoxic. Therefore, one of the main therapeutic approaches to cure or delay AD onset and progression is targeting Aβ aggregation. In the present study, we show that a pool of human gamma immunoglobulins (IgG) protected cortical neurons from the challenge with Aβ oligomers, as assayed by MTT reduction, caspase-3 activation and cytoskeleton integrity. In addition, we report the inhibitory effect of IgG on Aβ aggregation, as shown by Thioflavin T assay, size exclusion chromatography and atomic force microscopy. Similar results were obtained with Palivizumab, a human anti-sincitial virus antibody. In order to dissect the important domains, we cleaved the pool of human IgG with papain to obtain Fab and Fc fragments. Using these cleaved fragments, we functionally identified Fab as the immunoglobulin fragment inhibiting Aβ aggregation, a result that was further confirmed by an in silico structural model. Interestingly, bioinformatic tools show a highly conserved structure able to bind amyloid in the Fab region. Overall, our data strongly support the inhibitory effect of human IgG on Aβ aggregation and its neuroprotective role. PMID:28467807

  5. IgG4 autoantibodies against muscle-specific kinase undergo Fab-arm exchange in myasthenia gravis patients.

    Science.gov (United States)

    Koneczny, Inga; Stevens, Jo A A; De Rosa, Anna; Huda, Saif; Huijbers, Maartje G; Saxena, Abhishek; Maestri, Michelangelo; Lazaridis, Konstantinos; Zisimopoulou, Paraskevi; Tzartos, Socrates; Verschuuren, Jan; van der Maarel, Silvère M; van Damme, Philip; De Baets, Marc H; Molenaar, Peter C; Vincent, Angela; Ricciardi, Roberta; Martinez-Martinez, Pilar; Losen, Mario

    2017-02-01

    Autoimmunity mediated by IgG4 subclass autoantibodies is an expanding field of research. Due to their structural characteristics a key feature of IgG4 antibodies is the ability to exchange Fab-arms with other, unrelated, IgG4 molecules, making the IgG4 molecule potentially monovalent for the specific antigen. However, whether those disease-associated antigen-specific IgG4 are mono- or divalent for their antigens is unknown. Myasthenia gravis (MG) with antibodies to muscle specific kinase (MuSK-MG) is a well-recognized disease in which the predominant pathogenic IgG4 antibody binds to extracellular epitopes on MuSK at the neuromuscular junction; this inhibits a pathway that clusters the acetylcholine (neurotransmitter) receptors and leads to failure of neuromuscular transmission. In vitro Fab-arm exchange-inducing conditions were applied to MuSK antibodies in sera, purified IgG4 and IgG1-3 sub-fractions. Solid-phase cross-linking assays were established to determine the extent of pre-existing and inducible Fab-arm exchange. Functional effects of the resulting populations of IgG4 antibodies were determined by measuring inhibition of agrin-induced AChR clustering in C2C12 cells. To confirm the results, κ/κ, λ/λ and hybrid κ/λ IgG4s were isolated and tested for MuSK antibodies. At least fifty percent of patients had IgG4, but not IgG1-3, MuSK antibodies that could undergo Fab-arm exchange in vitro under reducing conditions. Also MuSK antibodies were found in vivo that were divalent (monospecific for MuSK). Fab-arm exchange with normal human IgG4 did not prevent the inhibitory effect of serum derived MuSK antibodies on AChR clustering in C2C12 mouse myotubes. The results suggest that a considerable proportion of MuSK IgG4 could already be Fab-arm exchanged in vivo. This was confirmed by isolating endogenous IgG4 MuSK antibodies containing both κ and λ light chains, i.e. hybrid IgG4 molecules. These new findings demonstrate that Fab-arm exchanged antibodies

  6. Cholangiocarcinoma with respect to IgG4 Reaction

    Directory of Open Access Journals (Sweden)

    Kenichi Harada

    2014-01-01

    Full Text Available IgG4 reactions marked by infiltration of IgG4-positive plasma cells in affected organs occur in cancer patients and in patients with IgG4-related diseases. Extrahepatic cholangiocarcinomas including gall bladder cancer are often accompanied by significant IgG4 reactions; these reactions show a negative correlation with CD8-positive cytotoxic T cells, suggesting that the evasion of immune surveillance is associated with cytotoxic T cells. The regulatory cytokine IL-10 may induce IgG4-positive plasma cell differentiation or promote B cell switching to IgG4 in the presence of IL-4. Cholangiocarcinoma cells may function as nonprofessional antigen presenting cells that indirectly induce IgG4 reactions via the IL-10-producing cells and/or these may act as Foxp3-positive and IL-10-producing cells that directly induce IgG4 reactions. Moreover, IgG4-related disease is a high-risk factor for cancer development; IgG4-related sclerosing cholangitis (IgG4-SC cases associated with cholangiocarcinoma or its precursor lesion biliary intraepithelial neoplasia (BilIN have been reported. IgG4-positive cell infiltration is an important finding of IgG4-SC but is not a histological hallmark of IgG4-SC. For the diagnosis of IgG4-SC, its differentiation from cholangiocarcinoma remains important.

  7. Fc gamma receptor IIIB (Fc gamma RIIIB) polymorphisms are associated with clinical malaria in Ghanaian children

    DEFF Research Database (Denmark)

    Adu, Bright; Dodoo, Daniel; Adukpo, Selorme

    2012-01-01

    Plasmodium falciparum malaria kills nearly a million people annually. Over 90% of these deaths occur in children under five years of age in sub-Saharan Africa. A neutrophil mediated mechanism, the antibody dependent respiratory burst (ADRB), was recently shown to correlate with protection from...... by allele specific restriction enzyme digestion. FCGR3B-exon 3 was sequenced in 585 children, aged 1 to 12 years living in a malaria endemic region of Ghana. Multivariate logistic regression analysis found no association between Fc¿RIIA-166H/R polymorphism and clinical malaria. The A-allele of FCGR3B-c.233C...... malaria vaccines....

  8. Histopathology of IgG4-Related Autoimmune Hepatitis and IgG4-Related Hepatopathy in IgG4-Related Disease.

    Science.gov (United States)

    Nakanuma, Yasuni; Ishizu, Yoji; Zen, Yoh; Harada, Kenichi; Umemura, Takeji

    2016-08-01

    Immunoglobulin G4-related disease (IgG4-RD) is a systemic disease involving many organs; it includes IgG4-related sclerosing cholangitis and inflammatory pseudotumor in the hepatobiliary system. Two types of hepatic parenchymal involvement have been reported in IgG4-RD: IgG4-related autoimmune hepatitis (AIH) and IgG4-hepatopathy. Moreover, only three cases of IgG4-related AIH have been reported. Immunoglobulin G4-related AIH is clinicopathologically similar to AIH, except for an elevated serum IgG4 level and heavy infiltration of IgG4-positive plasma cells in the liver tissue. Interestingly, IgG4-related AIH can be complicated by well-known IgG4-RD(s). Immunoglobulin G4-hepatopathy, which includes various histopathological lesions encountered in the liver of patients with type I autoimmune pancreatitis, is classified into five histological categories: portal inflammation, large bile duct damage, portal sclerosis, lobular hepatitis, and cholestasis. Immunoglobulin G4-hepatopathy is currently a collective term covering hepatic lesions primarily or secondarily related to IgG4-related sclerosing cholangitis and type 1 autoimmune pancreatitis. In conclusion, the liver is not immune to IgG4-RD, and at least two types of hepatic involvement in IgG4-RD have been reported: IgG4-related AIH and IgG4-hepatopathy. Additional studies are required to clarify their precise clinical significance with respect to IgG4-RD and inherent liver diseases. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  9. Anti-proteinase 3 anti-neutrophil cytoplasm autoantibodies recapitulate systemic vasculitis in mice with a humanized immune system.

    Directory of Open Access Journals (Sweden)

    Mark A Little

    Full Text Available Evidence is lacking for direct pathogenicity of human anti-proteinase-3 (PR3 antibodies in development of systemic vasculitis and granulomatosis with polyangiitis (GPA, Wegener's granulomatosis. Progress in study of these antibodies in rodents has been hampered by lack of PR3 expression on murine neutrophils, and by different Fc-receptor affinities for IgG across species. Therefore, we tested whether human anti-PR3 antibodies can induce acute vasculitis in mice with a human immune system. Chimeric mice were generated by injecting human haematopoietic stem cells into irradiated NOD-scid-IL2Rγ⁻/⁻ mice. Matched chimera mice were treated with human IgG from patients with: anti-PR3 positive renal and lung vasculitis; patients with non-vasculitic renal disease; or healthy controls. Six-days later, 39% of anti-PR3 treated mice had haematuria, compared with none of controls. There was punctate bleeding on the surface of lungs of anti-PR3 treated animals, with histological evidence of vasculitis and haemorrhage. Anti-PR3 treated mice had mild pauci-immune proliferative glomerulonephritis, with infiltration of human and mouse leukocytes. In 3 mice (17% more severe glomerular injury was present. There were no glomerular changes in controls. Human IgG from patients with anti-PR3 autoantibodies is therefore pathogenic. This model of anti-PR3 antibody-mediated vasculitis may be useful in dissecting mechanisms of microvascular injury.

  10. Anti-proteinase 3 anti-neutrophil cytoplasm autoantibodies recapitulate systemic vasculitis in mice with a humanized immune system.

    LENUS (Irish Health Repository)

    Little, Mark A

    2012-01-01

    Evidence is lacking for direct pathogenicity of human anti-proteinase-3 (PR3) antibodies in development of systemic vasculitis and granulomatosis with polyangiitis (GPA, Wegener\\'s granulomatosis). Progress in study of these antibodies in rodents has been hampered by lack of PR3 expression on murine neutrophils, and by different Fc-receptor affinities for IgG across species. Therefore, we tested whether human anti-PR3 antibodies can induce acute vasculitis in mice with a human immune system. Chimeric mice were generated by injecting human haematopoietic stem cells into irradiated NOD-scid-IL2Rγ⁻\\/⁻ mice. Matched chimera mice were treated with human IgG from patients with: anti-PR3 positive renal and lung vasculitis; patients with non-vasculitic renal disease; or healthy controls. Six-days later, 39% of anti-PR3 treated mice had haematuria, compared with none of controls. There was punctate bleeding on the surface of lungs of anti-PR3 treated animals, with histological evidence of vasculitis and haemorrhage. Anti-PR3 treated mice had mild pauci-immune proliferative glomerulonephritis, with infiltration of human and mouse leukocytes. In 3 mice (17%) more severe glomerular injury was present. There were no glomerular changes in controls. Human IgG from patients with anti-PR3 autoantibodies is therefore pathogenic. This model of anti-PR3 antibody-mediated vasculitis may be useful in dissecting mechanisms of microvascular injury.

  11. Construction of a bimolecular fluorescence complementation (BiFC ...

    African Journals Online (AJOL)

    DR. NJ TONUKARI

    2012-08-02

    Aug 2, 2012 ... Accepted 8 June, 2012. Protein–protein interactions are essential for signal transduction in cells. ... BiFC is a novel technology that is used for identifying .... occasional fluorescence was observed, it was very weak ... Light field.

  12. Catalase activity of IgG antibodies from the sera of healthy donors and patients with schizophrenia.

    Science.gov (United States)

    Ermakov, Evgeny A; Smirnova, Ludmila P; Bokhan, Nikolay A; Semke, Arkadiy V; Ivanova, Svetlana A; Buneva, Valentina N; Nevinsky, Georgy A

    2017-01-01

    We present first evidence showing that some electrophoretically homogeneous IgGs from the sera of patients with schizophrenia (36.4%) and their Fab and F(ab)2 fragments as well as from healthy donors (33.3%) possess catalase activity. The relative catalase activity of IgGs from the sera of individual schizophrenia patients (and healthy donors) significantly varied from patient to patient, but the activity of IgGs from healthy donors is on average 15.8-fold lower than that for schizophrenia patients. After extensive dialysis of purified IgGs against EDTA chelating metal ions, the relative catalase activity of IgGs decreases on average approximately 2.5-3.7-fold; all IgGs possess metal-dependent and independent catalase activity. The addition of external Me2+ ions to dialyzed and non-dialyzed IgGs leads to a significant increase in their activity. The best activator of dialyzed and non-dialyzed IgGs is Co2+, the activation by Cu2+, Mn2+, and Ni2+ ions were rare and always lower than by Co2+. Every IgG preparation demonstrates several individual sets of very well expressed pH optima in the pH range from 4.0 to 9.5. These data speak for the individual repertoire of catalase IgGs in every person and an extreme diversity of abzymes in their pH optima and activation by different metal ions. It is known that antioxidant enzymes such as superoxide dismutases, catalases, and glutathione peroxidases represent critical defense mechanisms preventing oxidative modifications of DNA, proteins, and lipids. Catalase activity of human IgGs could probably also play a major role in the protection of organisms from oxidative stress and toxic compounds.

  13. IgG4-related kidney disease – an update

    Science.gov (United States)

    Kawano, Mitsuhiro; Saeki, Takako

    2015-01-01

    Purpose of review IgG4-related disease (IgG4-RD) is a recently recognized systemic inflammatory disorder that can affect most organs/tissues such as sarcoidosis. The kidney is a frequently affected organ with tubulointerstitial nephritis (TIN), the representative lesion of IgG4-RD. This review focuses on the latest knowledge of IgG4-related kidney disease (IgG4-RKD). Recent findings A wide range of renal manifestations of IgG4-RD, that is TIN, membranous glomerulonephritis (MGN) and other glomerular lesions, and pyelitis, are collectively referred to as IgG4-RKD. Clinically, decreased renal function, or characteristic imaging findings such as multiple low-density lesions on contrast-enhanced computed tomography or diffuse thickening of the renal pelvic wall, are typical presenting features. Although a rapid response to corticosteroid therapy is a very important feature of IgG4-TIN, in cases in which renal function is moderately to severely decreased before therapy, only partial recovery of renal function is obtained. Summary TIN with characteristic imaging findings is a typical manifestation of IgG4-RKD in the interstitium, while MGN is a representative manifestation of the glomerular lesions. Although IgG4 is a central feature of IgG4-RD, the recent discovery of IgG4-negative IgG4-RD raises questions about the causative role of the IgG4 molecule in this context. PMID:25594543

  14. Copy number variation of Fc gamma receptor genes in HIV-infected and HIV-tuberculosis co-infected individuals in sub-Saharan Africa.

    Directory of Open Access Journals (Sweden)

    Lee R Machado

    Full Text Available AIDS, caused by the retrovirus HIV, remains the largest cause of morbidity in sub-Saharan Africa yet almost all genetic studies have focused on cohorts from Western countries. HIV shows high co-morbidity with tuberculosis (TB, as HIV stimulates the reactivation of latent tuberculosis (TB. Recent clinical trials suggest that an effective anti-HIV response correlates with non-neutralising antibodies. Given that Fcγ receptors are critical in mediating the non-neutralising effects of antibodies, analysis of the extensive variation at Fcγ receptor genes is important. Single nucleotide variation and copy number variation (CNV of Fcγ receptor genes affects the expression profile, activatory/inhibitory balance, and IgG affinity of the Fcγ receptor repertoire of each individual. In this study we investigated whether CNV of FCGR2C, FCGR3A and FCGR3B as well as the HNA1 allotype of FCGR3B is associated with HIV load, response to highly-active antiretroviral therapy (HAART and co-infection with TB. We confirmed an effect of TB-co-infection status on HIV load and response to HAART, but no conclusive effect of the genetic variants we tested. We observed a small effect, in Ethiopians, of FCGR3B copy number, where deletion was more frequent in HIV-TB co-infected patients than those infected with HIV alone.

  15. IgG4-Related Perineural Disease

    Directory of Open Access Journals (Sweden)

    Dai Inoue

    2012-01-01

    Full Text Available Aims. To elucidate characteristics of IgG4-related disease involving the peripheral nervous system. Methods. Retrospective review of 106 patients with IgG4-related disease identified 21 peripheral nerve lesions in 7 patients. Clinicopathological and radiological features were examined. Results. Peripheral nerve lesions were commonly identified in orbital or paravertebral area, involving orbital (=9, optic (=4, spinal (=7, and great auricular nerves (=1. The predominant radiological feature was a distinct perineural soft tissue mass, ranging 8 to 30 mm in diameter. Histologically, the epineurium was preferentially involved by massive lymphoplasmacytic infiltration rich in IgG4+ plasma cells. All lesions were neurologically asymptomatic and steroid-responsive at the first presentation, but one recurrent lesion around the optic nerve caused failing vision. Conclusion. IgG4-related disease of the peripheral nervous system is characterized by orbital or paravertebral localization, perineural mass formation, and rare neurologic symptoms. The term “IgG4-related perineural disease” seems appropriate to describe this entity.

  16. Validation of high throughput screening of human sera for detection of anti-PA IgG by Enzyme-Linked Immunosorbent Assay (ELISA) as an emergency response to an anthrax incident

    Science.gov (United States)

    Semenova, Vera A.; Steward-Clark, Evelene; Maniatis, Panagiotis; Epperson, Monica; Sabnis, Amit; Schiffer, Jarad

    2017-01-01

    To improve surge testing capability for a response to a release of Bacillus anthracis, the CDC anti-Protective Antigen (PA) IgG Enzyme-Linked Immunosorbent Assay (ELISA) was re-designed into a high throughput screening format. The following assay performance parameters were evaluated: goodness of fit (measured as the mean reference standard r2), accuracy (measured as percent error), precision (measured as coefficient of variance (CV)), lower limit of detection (LLOD), lower limit of quantification (LLOQ), dilutional linearity, diagnostic sensitivity (DSN) and diagnostic specificity (DSP). The paired sets of data for each sample were evaluated by Concordance Correlation Coefficient (CCC) analysis. The goodness of fit was 0.999; percent error between the expected and observed concentration for each sample ranged from −4.6% to 14.4%. The coefficient of variance ranged from 9.0% to 21.2%. The assay LLOQ was 2.6 μg/mL. The regression analysis results for dilutional linearity data were r2 = 0.952, slope = 1.02 and intercept = −0.03. CCC between assays was 0.974 for the median concentration of serum samples. The accuracy and precision components of CCC were 0.997 and 0.977, respectively. This high throughput screening assay is precise, accurate, sensitive and specific. Anti-PA IgG concentrations determined using two different assays proved high levels of agreement. The method will improve surge testing capability 18-fold from 4 to 72 sera per assay plate. PMID:27814939

  17. Validation of high throughput screening of human sera for detection of anti-PA IgG by Enzyme-Linked Immunosorbent Assay (ELISA) as an emergency response to an anthrax incident.

    Science.gov (United States)

    Semenova, Vera A; Steward-Clark, Evelene; Maniatis, Panagiotis; Epperson, Monica; Sabnis, Amit; Schiffer, Jarad

    2017-01-01

    To improve surge testing capability for a response to a release of Bacillus anthracis, the CDC anti-Protective Antigen (PA) IgG Enzyme-Linked Immunosorbent Assay (ELISA) was re-designed into a high throughput screening format. The following assay performance parameters were evaluated: goodness of fit (measured as the mean reference standard r 2 ), accuracy (measured as percent error), precision (measured as coefficient of variance (CV)), lower limit of detection (LLOD), lower limit of quantification (LLOQ), dilutional linearity, diagnostic sensitivity (DSN) and diagnostic specificity (DSP). The paired sets of data for each sample were evaluated by Concordance Correlation Coefficient (CCC) analysis. The goodness of fit was 0.999; percent error between the expected and observed concentration for each sample ranged from -4.6% to 14.4%. The coefficient of variance ranged from 9.0% to 21.2%. The assay LLOQ was 2.6 μg/mL. The regression analysis results for dilutional linearity data were r 2  = 0.952, slope = 1.02 and intercept = -0.03. CCC between assays was 0.974 for the median concentration of serum samples. The accuracy and precision components of CCC were 0.997 and 0.977, respectively. This high throughput screening assay is precise, accurate, sensitive and specific. Anti-PA IgG concentrations determined using two different assays proved high levels of agreement. The method will improve surge testing capability 18-fold from 4 to 72 sera per assay plate. Published by Elsevier Ltd.

  18. At least two Fc Neu5Gc residues of monoclonal antibodies are required for binding to anti-Neu5Gc antibody.

    Science.gov (United States)

    Yu, Chuanfei; Gao, Kai; Zhu, Lei; Wang, Wenbo; Wang, Lan; Zhang, Feng; Liu, Chunyu; Li, Meng; Wormald, Mark R; Rudd, Pauline M; Wang, Junzhi

    2016-01-29

    Two non-human glycan epitopes, galactose-α-1,3-galactose (α-gal) and Neu5Gc-α-2-6-galactose (Neu5Gc) have been shown to be antigenic when attached to Fab oligosaccharides of monoclonal antibodies (mAbs) , while α-gal attached to Fc glycans was not. However, the antigenicity of Neu5Gc on the Fc glycans remains unclear in the context that most mAbs carry only Fc glycans. After studying two clinical mAbs carrying significant amounts of Fc Neu5Gc, we show that their binding activity with anti-Neu5Gc antibody resided in a small subset of mAbs carrying two or more Fc Neu5Gc, while mAbs harboring only one Neu5Gc showed no reactivity. Since most Neu5Gc epitopes were distributed singly on the Fc of mAbs, our results suggest that the potential antigenicity of Fc Neu5Gc is low. Our study could be referenced in the process design and optimization of mAb production in murine myeloma cells and in the quality control of mAbs for industries and regulatory authorities.

  19. A new approach for generating bispecific antibodies based on a common light chain format and the stable architecture of human immunoglobulin G1.

    Science.gov (United States)

    De Nardis, Camilla; Hendriks, Linda J A; Poirier, Emilie; Arvinte, Tudor; Gros, Piet; Bakker, Alexander B H; de Kruif, John

    2017-09-01

    Bispecific antibodies combine two different antigen-binding sites in a single molecule, enabling more specific targeting, novel mechanisms of action, and higher clinical efficacies. Although they have the potential to outperform conventional monoclonal antibodies, many bispecific antibodies have issues regarding production, stability, and pharmacokinetic properties. Here, we describe a new approach for generating bispecific antibodies using a common light chain format and exploiting the stable architecture of human immunoglobulin G 1 We used iterative experimental validation and computational modeling to identify multiple Fc variant pairs that drive efficient heterodimerization of the antibody heavy chains. Accelerated stability studies enabled selection of one Fc variant pair dubbed "DEKK" consisting of substitutions L351D and L368E in one heavy chain combined with L351K and T366K in the other. Solving the crystal structure of the DEKK Fc region at a resolution of 2.3 Å enabled detailed analysis of the interactions inducing CH3 interface heterodimerization. Local shifts in the IgG backbone accommodate the introduction of lysine side chains that form stabilizing salt-bridge interactions with substituted and native residues in the opposite chain. Overall, the CH3 domain adapted to these shifts at the interface, yielding a stable Fc conformation very similar to that in wild-type IgG. Using the DEKK format, we generated the bispecific antibody MCLA-128, targeting human EGF receptors 2 and 3. MCLA-128 could be readily produced and purified at industrial scale with a standard mammalian cell culture platform and a routine purification protocol. Long-term accelerated stability assays confirmed that MCLA-128 is highly stable and has excellent biophysical characteristics. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Dicty_cDB: FC-AC21 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-AC21 (Link to dictyBase) - - - Contig-U15104-1 FC-AC21E (Li...nk to Original site) - - - - - - FC-AC21E 527 Show FC-AC21 Library FC (Link to library) Clone ID FC-AC21 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U15104-1 Original site URL http://dict...ce KDSLDVIIFPEMVKLVGLTPNTMEKVLTYFQDNDTIDLSTFPMEIQVEQLSGKYIFICTH KQKDQRCGYCGPILVDQLRDQIKERSLEKEIQVFGTSHVGGHKY... Frames) Frame A: KDSLDVIIFPEMVKLVGLTPNTMEKVLTYFQDNDTIDLSTFPMEIQVEQLSGKYIFICTH KQ

  1. Circulating plasmablasts/plasma cells: a potential biomarker for IgG4-related disease.

    Science.gov (United States)

    Lin, Wei; Zhang, Panpan; Chen, Hua; Chen, Yu; Yang, Hongxian; Zheng, Wenjie; Zhang, Xuan; Zhang, Fengxiao; Zhang, Wen; Lipsky, Peter E

    2017-02-10

    Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a multisystem fibroinflammatory disease. We previously reported that a circulating cell population expressing CD19 + CD24 - CD38 hi was increased in patients with IgG4-RD. In this study, we aimed to document that this cell population represented circulating plasmablasts/plasma cells, to identify the detailed phenotype and gene expression profile of these IgG4-secreting plasmablasts/plasma cells, and to determine whether this B-cell lineage subset could be a biomarker in IgG4-related disease (IgG4-RD). A total of 42 untreated patients with IgG4-RD were evaluated. Peripheral B-cell subsets, including CD19 + CD24 - CD38 hi plasmablasts/plasma cells, CD19 + CD24 + CD38 - memory B cells, CD19 + CD24 int CD38 int naïve B cells, and CD19 + CD24 hi CD38 hi regulatory B cells, were assessed and sorted by flow cytometry. Microarray analysis was used to measure gene expression of circulating B-cell lineage subsets. Further characterization of CD19 + CD24 - CD38 hi plasmablasts/plasma cells was carried out by evaluating additional surface markers, including CD27, CD95, and human leukocyte antigen (HLA)-DR, by flow cytometric assay. In addition, various B-cell lineage subsets were cultured in vitro and IgG4 concentrations were measured by cytometric bead array. In untreated patients with IgG4-RD, the peripheral CD19 + CD24 - CD38 hi plasmablast/plasma cell subset was increased and positively correlated with serum IgG4 levels, the number of involved organs, and the IgG4-related Disease Responder Index. It decreased after treatment with glucocorticoids. Characterization of the plasmablast/plasma cell population by gene expression profiling documented a typical plasmablast/plasma cell signature with higher expression of X-box binding protein 1 and IFN regulatory factor 4, but lower expression of paired box gene 5 and B-cell lymphoma 6 protein. In addition, CD27, CD95, and HLA-DR were highly expressed on CD19 + CD24 - CD38 hi

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

    Science.gov (United States)

    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

  3. IgG4-related Disease of the Genitourinary Tract

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    Mukul K. Divatia

    2014-02-01

    Full Text Available IgG4-related disease (IgG4-RD is a recently established albeit well recognized fibro-inflammatory condition with distinctive features including a characteristic histopathological appearance; a propensity to develop tumefactive lesions in multiple body sites; and oft elevated serum IgG4 levels. The consensus statement on IgG-4 RD equips practicing pathologists with a set of working guidelines for the diagnosis of pathologic lesions identified in a host of different organ system affected with this disease. The diagnosis of IgG4-RD requires the combined presence of the characteristic histopathological appearance and increased numbers of IgG4-positive plasma cells. The essential histopathological features include a dense lymphoplasmacytic infiltrate, a storiform pattern of fibrosis, and obliterative phlebitis. Tissue IgG4-positive plasma cell counts and IgG4: IgG ratios are significant ancillary aids in establishing the diagnosis. The spectrum of IgG4-RD continues to expand and involve multiple body sites. The genitourinary system comprising of the kidneys, ureters, urinary bladder, urethra, prostate gland, testes and penis is one of the multiple organ systems to be affected by IgG4-RD. This review describes the clinical and histopathologic patterns of involvement of the genitourinary system by IgG4-RD, in association with serologic and radiological features. [J Interdiscipl Histopathol 2014; 2(1.000: 3-18

  4. Inhibition of complement activation by IgG4 antibodies

    NARCIS (Netherlands)

    van der Zee, J. S.; van Swieten, P.; Aalberse, R. C.

    1986-01-01

    Prolonged exposure to antigens may result in high IgG4 antibody titres as was shown in a previous paper (Aalberse et al., 1983b). In novice bee keepers, a shift in the IgG1/IgG4 ratio of the response against phospholipase-A (PLA; a major component of bee venom) occurred. This resulted in an

  5. Effects of microparticle size and Fc density on macrophage phagocytosis.

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    Patricia Pacheco

    Full Text Available Controlled induction of phagocytosis in macrophages offers the ability to therapeutically regulate the immune system as well as improve delivery of chemicals or biologicals for immune processing. Maximizing particle uptake by macrophages through Fc receptor-mediated phagocytosis could lead to new delivery mechanisms in drug or vaccine development. Fc ligand density and particle size were examined independently and in combination in order to optimize and tune the phagocytosis of opsonized microparticles. We show the internalization efficiency of small polystyrene particles (0.5 µm to 2 µm is significantly affected by changes in Fc ligand density, while particles greater than 2 µm show little correlation between internalization and Fc density. We found that while macrophages can efficiently phagocytose a large number of smaller particles, the total volume of phagocytosed particles is maximized through the non-specific uptake of larger microparticles. Therefore, larger microparticles may be more efficient at delivering a greater therapeutic payload to macrophages, but smaller opsonized microparticles can deliver bio-active substances to a greater percentage of the macrophage population. This study is the first to treat as independent variables the physical and biological properties of Fc density and microparticle size that initiate macrophage phagocytosis. Defining the physical and biological parameters that affect phagocytosis efficiency will lead to improved methods of microparticle delivery to macrophages.

  6. Clonal expansion of CD4+ Cytotoxic T Lymphocytes in IgG4-related disease

    Science.gov (United States)

    Mattoo, Hamid; Mahajan, Vinay S.; Maehara, Takashi; Deshpande, Vikram; Della-Torre, Emanuel; Wallace, Zachary S.; Kulikova, Maria; Drijvers, Jefte M.; Daccache, Joe; Carruthers, Mollie N.; Castellino, Flavia; Stone, James R.; Stone, John H.; Pillai, Shiv

    2016-01-01

    Background IgG4-related disease (IgG4-RD) is a systemic condition of unknown etiology, characterized by highly fibrotic lesions with dense lymphoplasmacytic infiltrates. CD4+ T cells constitute the major inflammatory cell population in IgG4-RD lesions. Objective We used an unbiased approach to characterize CD4+ T cell subsets in IgG4-RD subjects based on their clonal expansion and their ability to infiltrate affected tissue sites. Methods We used flow cytometry to identify CD4+ effector/memory T cells (TEM) in a cohort of 101 IgG4-related disease (IgG4-RD) patients. These expanded cells were characterized by gene expression analysis and flow cytometry. Next-generation sequencing of the T cell receptor β chain gene was performed on CD4+SLAMF7+ CTLs and CD4+GATA3+ TH2 cells in a subset of patients to identify their clonality. Tissue infiltration by specific T cells was examined using quantitative multi-color imaging. Results CD4+ effector/memory T cells with a cytolytic phenotype were expanded in IgG4-RD patients. Next-generation sequencing revealed prominent clonal expansions of these CD4+CTLs but not CD4+GATA3+ memory TH2 cells in subjects with IgG4-RD. The dominant T cells infiltrating a range of inflamed IgG4-RD tissue sites were clonally-expanded CD4+CTLs that expressed SLAMF7, granzyme A, IL-1β, and TGF-β1. Clinical remission induced by rituximab-mediated B cell depletion was associated with a reduction in disease-associated CD4+ CTLs Conclusions IgG4-RD is prominently linked to clonally-expanded, IL-1β, and TGF- β1 secreting, CD4+ CTLs in peripheral blood as well as in inflammatory tissue lesions. These active, terminally-differentiated, cytokine-secreting effector CD4+ T cells are now linked to a human disease characterized by chronic inflammation and fibrosis. PMID:26971690

  7. Emerging functions of natural IgM and its Fc receptor FCMR in immune homeostasis

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    Hongsheng eWang

    2016-03-01

    Full Text Available Most natural IgM antibodies are encoded by germline Ig sequences and are produced in large quantities by both mice and humans in the absence of intentional immunization. Natural IgM are reactive with many conserved epitopes, including those shared by microorganisms and autoantigens. As a result, these antibodies play important roles in clearing intruding pathogens, as well as apoptotic/necrotic cells and otherwise damaged tissues. While natural IgM binds to target structures with low affinity due to a lack of significant selection by somatic hypermutation, its pentameric structure with 10 antigen binding sites enables these antibodies to bind multivalent target antigens with high avidity. Opsonization of antigen complexed with IgM is mediated by cell surface Fc receptors. While the existence of Fc alpha/mu receptor has been known for some time, only recently has the Fc receptor specific for IgM (FCMR been identified. In this review, we focus on our current understandings of how natural IgM and FCMR regulate the immune system and maintain homeostasis under physiological and pathological conditions.

  8. [Diagnosis of human brucellosis. Role of pH in the seroagglutination test and influence of pH on the agglutinating activity of IgM, IgG and IgA antibodies].

    Science.gov (United States)

    Rubio Vallejo, Manuel; del Pozo, José L; Del Pozo León, José Luis; Hernández-Molina, Juan Manuel; Dorronsoro Ibero, Inés; Marrodán Ciordia, Teresa; Díaz García, Ramón

    2002-04-01

    To evaluate the role of pH in the seroagglutination test (SAT)and Rose Bengal (RB) test, and to determine the influence of pH on the agglutinating activity of IgM, IgG and IgA antibodies. The SAT was performed at pH 7.2 or pH 5.0 in standard microtiter-type polystyrene plates using Ring Test antigen or the Brucella suspension (BRUCAPT) provided in the Brucellacapt kits. Specific antibodies against native hapten were determined by radial immunodiffusion. Additionally, IgG, IgA and IgM fractions were separated from 8 sera by absorption chromatography and their agglutinating capacity was studied at pH 7.2 and 5.0. We studied 72 sera from patients with clinical brucellosis taken at the time of hospitalization, 16 from persons in contact with infected animals, and 16 from healthy donors. SAT results at pH 5.0 correlated with those obtained with the Rose Bengal test. Four Rose Bengal-positive sera were found to be SAT-negative at pH 7.2 and SAT-positive at pH 5.0. SAT performed at pH 5.0 with BRUCAPT antigen yielded higher titers than tests performed at pH 7.2 or 5.0 with Ring Test antigen (p IgA fractions were SAT-negative at pH 7.2 and SAT-positive at pH 5.0; the other 5 agglutinated at both pH conditions and were DTT-sensitive. All IgA fractions but one were positive by Rose Bengal. Agglutinating activity of the IgM fraction was not affected by pH. The SAT performed with the buffer and antigen suspension included in the Brucellacapt kit (pH 5.0) is highly useful for detecting agglutinating and non-agglutinating antibodies at pH 7.2.

  9. Asma y deficiencia de subclases de IgG Asthma and IgG subclases deficiency

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    Lucía Santamaría Ortiz

    1995-04-01

    Full Text Available

    Se estudiaron 45 pacientes asmáticos adultos de difícil manejo, de más de 5 años de evolución, 37 de ellos esteroide dependientes y 8 no dependientes, con asma alérgica o intrínseca y algunos con Infecciones respiratorias recurrentes de predominio viral. Por nefelometría se midieron los niveles séricos de las IgsG, M y A, y por ELISA se determinó la IgE total. Se encontraron 4 pacientes con deficiencia de IgG total, en el grupo de los esteroide dependientes. Mediante ELISA tipo sandwich y con anticuerpos monoclonales específicos para las sub clases de IgG se investigaron los niveles sé ricos de IgG1, 2, 3 y 4. En el 55.6% de los enfermos se encontraron una O más deficiencias de sub clases. No hubo diferencias significativas entre los grupos esteroide y no esteroide dependientes, ni entre los asmáticos alérgicos e intrínsecos, ni entre los con infección recurrente o sin ella. predominó la deficiencia de IgG1; en total el 46.7% de los pacientes tenían deficiencia aislada o combinada de IgG1, el 31.1% de IgG2, el 24.4% de IgG3 y el 17.8% de Igd4. La alta incidencia de deficiencia de sub clases podría deberse a la acción de los esteroides o a una alteración en la regulación de la síntesis de Igs producida por un defecto Inmune primario. Esta deficiencia sería la responsable del comportamiento agresivo de la enfermedad.

    We studied 45 adult asthmatic patients with difficult to care disease and who had more than five years of evolution; they suffered from elther allergic or intrinsic asthma and some had experienced recurrent respiratory tract infections. predominantly of viral etiology. Serum levels of IgA, IgG and IgM were measured by nephelometry and total lgE was determined by an Enzyme-Linked immunosorbent Assay (ELISA. Total lg

  10. Measuring and manipulating brain connectivity with resting state functional connectivity magnetic resonance imaging (fcMRI) and transcranial magnetic stimulation (TMS).

    Science.gov (United States)

    Fox, Michael D; Halko, Mark A; Eldaief, Mark C; Pascual-Leone, Alvaro

    2012-10-01

    Both resting state functional magnetic resonance imaging (fcMRI) and transcranial magnetic stimulation (TMS) are increasingly popular techniques that can be used to non-invasively measure brain connectivity in human subjects. TMS shows additional promise as a method to manipulate brain connectivity. In this review we discuss how these two complimentary tools can be combined to optimally study brain connectivity and manipulate distributed brain networks. Important clinical applications include using resting state fcMRI to guide target selection for TMS and using TMS to modulate pathological network interactions identified with resting state fcMRI. The combination of TMS and resting state fcMRI has the potential to accelerate the translation of both techniques into the clinical realm and promises a new approach to the diagnosis and treatment of neurological and psychiatric diseases that demonstrate network pathology. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Live visualization of genomic loci with BiFC-TALE.

    Science.gov (United States)

    Hu, Huan; Zhang, Hongmin; Wang, Sheng; Ding, Miao; An, Hui; Hou, Yingping; Yang, Xiaojing; Wei, Wensheng; Sun, Yujie; Tang, Chao

    2017-01-11

    Tracking the dynamics of genomic loci is important for understanding the mechanisms of fundamental intracellular processes. However, fluorescent labeling and imaging of such loci in live cells have been challenging. One of the major reasons is the low signal-to-background ratio (SBR) of images mainly caused by the background fluorescence from diffuse full-length fluorescent proteins (FPs) in the living nucleus, hampering the application of live cell genomic labeling methods. Here, combining bimolecular fluorescence complementation (BiFC) and transcription activator-like effector (TALE) technologies, we developed a novel method for labeling genomic loci (BiFC-TALE), which largely reduces the background fluorescence level. Using BiFC-TALE, we demonstrated a significantly improved SBR by imaging telomeres and centromeres in living cells in comparison with the methods using full-length FP.

  12. Glycation of polyclonal IgGs: Effect of sugar excipients during stability studies.

    Science.gov (United States)

    Leblanc, Y; Bihoreau, N; Jube, M; Andre, M-H; Tellier, Z; Chevreux, G

    2016-05-01

    A number of intravenous immunoglobulin preparations are stabilized with sugar additives that may lead over time to undesirable glycation reactions especially in liquid formulation. This study aimed to evaluate the reactivity of sugar excipients on such preparations in condition of temperature, formulation and concentration commonly used for pharmaceutical products. Through an innovative LC-MS method reported to characterize post-translational modifications of IgGs Fc/2 fragments, a stability study of IVIg formulated with reducing and non-reducing sugars has been undertaken. The rate of polyclonal IgGs glycation was investigated during 6months at 5, 25, 30 and 40°C. High levels of glycation were observed with reducing sugars such as glucose and maltose in the first months of the stability study from 25°C. Non-reducing sugars presented a low reactivity even at the highest tested temperature (40°C). Furthermore, a site by site analysis was performed by MS/MS to determine the glycation sites which were mainly identified at Lys246, Lys248 and Lys324. This work points out the high probability of glycation reactions in some commercialized products and describes a useful method to characterize IVIg glycated products issued from reducing sugar excipients. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  13. Detection of Serum IgG4 Levels in Patients with IgG4-Related Disease and Other Disorders

    Science.gov (United States)

    Wang, Chenqiong; Wu, Xuefen; Miao, Ye; Xiong, Hui; Bai, Lin; Dong, Lingli

    2015-01-01

    Objective Elevated serum IgG4 levels are an important hallmark for diagnosing IgG4-related disease (IgG4-RD), but can also be observed in other diseases. This study aimed to compare two different testing methods for IgG4: ELISA and nephelometric assay. Both assays were used to measure serum IgG4 concentrations, and to assess the prevalence of high serum IgG4 levels in both IgG4-RD and non-IgG4-RD diseases. Methods A total of 80 serum samples were tested using the nephelometric assay and ELISA method that we established. Serum IgG4 concentrations were determined by ELISA for 957 patients with distinct diseases, including 12 cases of IgG4-RD and 945 cases of non-IgG4-RD. Results IgG4 levels from 80 selected serum samples examined by ELISA were in agreement with those detected using the nephelometry assay. Meanwhile, the serum IgG4 concentrations measured by ELISA were also consistent with the clinical diagnoses of patients with IgG4-RD during the course of disease. The Elevated levels of serum IgG4 (>1.35 g/L) were detected in all IgG4-RD (12/12) patients, and the prevalence of high IgG4 serum levels was 3.39% in non-IgG4-RD cases. Among them, the positive rates of serum IgG4 were 2.06% in patients with carcinoma and 6.3% in patients with other non-IgG4 autoimmune diseases. Conclusion Our established ELISA method is a reliable and convenient technique, which could be extensively used in the clinic to measure serum IgG4 levels. High levels of IgG4 were observed in IgG4-RD. However, this phenomenon could also be observed in other diseases, such as carcinomas and other autoimmune diseases. Thus, a diagnosis of IgG4 disease cannot only be dependent on the detection of elevated serum IgG4 levels. PMID:25885536

  14. IgG4-Related Disease of Bilateral Temporal Bones.

    Science.gov (United States)

    Li, Lilun; Ward, Bryan; Cocks, Margaret; Kheradmand, Amir; Francis, Howard W

    2017-03-01

    IgG4-related disease (IgG4-RD) is an idiopathic inflammatory condition that causes pseudotumor formation in single or multiple organs, including those of the head and neck. Temporal bone involvement is rare, with only 3 cases of unilateral temporal bone IgG4-RD described in the literature. We report the first known case of IgG4-RD of bilateral temporal bones and describe its clinical presentation, diagnosis, and treatment. The patient was a 52-year-old man with latent tuberculosis (TB) who presented with a 10-year history of bilateral profound hearing loss and vestibular dysfunction. Computed tomography and magnetic resonance imaging demonstrated bilateral labyrinthine destruction with invasion of the posterior fossa. Immunoglobulin level testing showed elevated total serum IgG levels with normal IgG4 levels. Bilateral mastoidectomies were performed, with biopsy samples demonstrating IgG4 staining with IgG4-positive plasma cells up to 40/HPF (high power field) on the right and 20/HPF on the left, consistent with bilateral IgG4-RD. IgG4-RD of bilateral temporal bones presents with chronic and progressive bilateral hearing loss and vestibular dysfunction. Clinical presentation and radiologic findings are nonspecific, and definitive diagnosis must be made with histopathology and immunostaining. Corticosteroids are therapeutic, but surgical resection may be necessary for temporal bone IgG4-RD to improve long-term remission.

  15. IgG4 Aortitis: A Case Report.

    Science.gov (United States)

    Marketkar, Shivali; LeGolvan, Mark

    2017-04-03

    IgG4 aortitis is one of the entities seen in the spectrum of IgG4-related disease (IgG4-RD). It is characterized by serologic (elevated serum IgG4) and histologic features including a lymphoplasmacytic infiltrate with increased numbers of IgG4-positive plasma cells, storiform fibrosis and obliterative phlebitis. Some studies have described a correlation between infections and IgG4 aortitis. We describe a patient with an aneurysm of the infrarenal descending abdominal aorta with features of IgG4-RD, as well as culture evidence of Streptococcus sanguis. [Full article available at http://rimed.org/rimedicaljournal-2017-04.asp].

  16. IgG4-related disease in autoimmune lymphoproliferative syndrome.

    Science.gov (United States)

    van de Ven, Annick A J M; Seidl, Maximilian; Drendel, Vanessa; Schmitt-Graeff, Annette; Voll, Reinhard E; Rensing-Ehl, Anne; Speckmann, Carsten; Ehl, Stephan; Warnatz, Klaus; Kollert, Florian

    2017-07-01

    A patient with autoimmune lymphoproliferative disorder (ALPS) developed IgG4-related disease. In retrospect, he had high levels of serum IgG4 for several years prior to presenting with IgG4-related pancreatitis. These high IgG4 levels were masked by hypergammaglobulinemia, a common feature of ALPS. We next screened 18 ALPS patients; four of them displayed increased levels of IgG4. Hence, IgG4-related disease should be considered in ALPS patients, especially in those manifesting lymphocytic organ infiltration or excessive hypergammaglobulinaemia. Screening of IgG4-related disease patients for ALPS-associated mutations would provide further information on whether this disease could be a late-onset atypical presentation of ALPS. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Natural Mosquito-Pathogen Hybrid IgG4 Antibodies in Vector Borne Diseases: A Hypothesis

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    Berlin L. Londono-Renteria

    2016-09-01

    Full Text Available Chronic exposure to antigens may favor the production of IgG4 antibodies over other antibody types. Recent studies have shown that up to a 30% of normal human IgG4 is bi-specific and is able to recognize two antigens of different nature. A requirement for this specificity is the presence of both eliciting antigens in the same time and at the same place where the immune response is induced. During transmission of most vector-borne diseases, the pathogen is delivered to the vertebrate host along with the arthropod saliva during blood feeding and previous studies have shown the existence of IgG4 antibodies against mosquito salivary allergens. However, there is very little ongoing research or information available regarding IgG4 bi-specificity with regards to infectious disease, particularly during immune responses to vector-borne diseases such as malaria, filariasis or dengue virus infection. Here, we provide background information and present our hypothesis that IgG4 may not only be a useful tool to measure exposure to infected mosquito bites, but that these bi-specific antibodies may also play an important role in modulation of the immune response against malaria and other vector-borne diseases in endemic settings.

  18. Proteolytic activity of IgGs from blood serum of wistar rats at experimental rheumatoid arthritis

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    Yu. Ya. Kit

    2014-10-01

    Full Text Available The aim of this work was to study the proteolytic activity of IgGs purified from blood serum of Wistar rats at experimental rheumatoid arthritis (ERA induced by an injection of bovine collagen of type II. Twenty rats were immunized with a preparation of bovine collagen II (Sigma-Aldrich, USA in the presence of complete Freund’s adjuvant. ERA development was determined by inflammation in limbs of treated animals. IgG preparations were isolated from blood serum of immunized and non-immunized animals by precipitation of antibodies with 33% ammonium sulfate followed by chromatography on the Protein G-Sepharose column. Human histone H1, bovine collagen II, calf thymus histones, myelin basic protein (MBP, bovine serum albumin (BSA, and bovine casein were used as substrates of the proteolytic activity of IgGs. It was found that IgG preparations from blood serum of rats with ERA were capable of cleaving histone H1 and MBP, however, they were catalytically inactive towards collagen II, casein, BSA, and core histones. IgGs from blood serum of non-immunized rats were proteolytically inactive towards all used protein substrates. Thus, we demonstrated that immunization of rats with bovine collagen II induced IgG-antibodies possessing the proteolytic activity towards histone H1 and MBP. This activity might be associated with the development of inflammatory processes in the immunized rats.

  19. [IgG4 immunohistochemistry in Riedle thyroiditis].

    Science.gov (United States)

    Wang, S; Luo, Y F; Cao, J L; Zhang, H; Shi, X H; Liang, Z Y; Feng, R E

    2017-03-08

    Objective: To observe the histopathological changes and immunohistochemical expression of IgG4 in Riedle thyroiditis (RT) and to study the relationship between RT and IgG4-related diseases (IgG4-RD). Methods: A total of 5 RT patients were collected from the Department of Pathology, Peking Union Medical College Hospital during April 2012 to August 2014. The clinical and immunohistochemical features were analyzed in the 5 patients. Histopathologic analysis was performed on hematoxylin and eosin-stained sections. Results: There were one male and four female patients, aged 52 to 78 years (median 59 years). Five cases were characterized by multiple nodules of thyroid, which increased year by year. All patients were found to have surrounding tissue compression symptoms and signs. Two female patients were found to have hypothyroidism. The serum concentration of IgG was elevated in 2 cases, and the serum concentration of IgG was not tested before operation in the remaining patients. By ultrasound, all presented as low echo or medium low echo. Strong echo occasionally appeared in hypoechoic nodules. Microscopically, fibrous tissue hyperplasia was infiltrated with varying numbers of lymphocytes and plasma cells. The occlusion of phlebitis was found in 4 cases and eosinophils were found in 3 cases. IgG4 counts and IgG4/IgG ratios in 5 cases were 20/HPF, 16%; 60/HPF, 82%; 22/HPF, 28%; 400/HPF, 266% and 33/HPF, 71%, respectively. Conclusions: With the similar pathological manifestations between RT and IgG4-RD, immunohistochemical staining shows that the number of IgG4 positive plasma cells and IgG4/IgG ratio of RT are increased in varying degrees. Some cases meet the diagnostic criteria of IgG4-RD, and speculate that some cases of RT belong to IgG4-RD.

  20. Pathological manifestations in lymphatic filariasis correlate with lack of inhibitory properties of IgG4 antibodies on IgE-activated granulocytes.

    Science.gov (United States)

    Prodjinotho, Ulrich F; von Horn, Charlotte; Debrah, Alex Y; Batsa Debrah, Linda; Albers, Anna; Layland, Laura E; Hoerauf, Achim; Adjobimey, Tomabu

    2017-07-01

    Helminth parasites are known to be efficient modulators of their host's immune system. To guarantee their own survival, they induce alongside the classical Th2 a strong regulatory response with high levels of anti-inflammatory cytokines and elevated plasma levels of IgG4. This particular antibody was shown in different models to exhibit immunosuppressive properties. How IgG4 affects the etiopathology of lymphatic filariasis (LF) is however not well characterized. Here we investigate the impact of plasma and affinity-purified IgG/IgG4 fractions from endemic normals (EN) and LF infected pathology patients (CP), asymptomatic microfilaraemic (Mf+) and amicrofilaraemic (Mf-) individuals on IgE/IL3 activated granulocytes. The activation and degranulation states were investigated by monitoring the expression of CD63/HLADR and the release of granule contents (neutrophil elastase (NE), eosinophil cationic protein (ECP) and histamine) respectively by flow cytometry and ELISA. We could show that the activation of granulocytes was inhibited in the presence of plasma from EN and Mf+ individuals whereas those of Mf- and CP presented no effect. This inhibitory capacity was impaired upon depletion of IgG in Mf+ individuals but persisted in IgG-depleted plasma from EN, where it strongly correlated with the expression of IgA. In addition, IgA-depleted fractions failed to suppress granulocyte activation. Strikingly, affinity-purified IgG4 antibodies from EN, Mf+ and Mf- individuals bound granulocytes and inhibited activation and the release of ECP, NE and histamine. In contrast, IgG4 from CP could not bind granulocytes and presented no suppressive capacity. Reduction of both the affinity to, and the suppressive properties of anti-inflammatory IgG4 on granulocytes was reached only when FcγRI and II were blocked simultaneously. These data indicate that IgG4 antibodies from Mf+, Mf- and EN, in contrast to those of CP, natively exhibit FcγRI/II-dependent suppressive properties on

  1. Production of double antibody for radioimmunoassay (sheep anti-rabbit IgG antiserum)

    International Nuclear Information System (INIS)

    Silva, S.R. da.

    1993-01-01

    A second antibody (sheep anti-rabbit IgG antiserum) to be used in RIAs in which the first antibody is raised in rabbits was produced. For this production, initially the IgG was isolated from rabbit serum and purified by sodium sulphate precipitation followed by ion exchange chromatography on DEAE-cellulose. Four sheep were immunized with 500 u g of purified rabbit IgG, emulsified in Freund Complete Adjuvant and administered by multisite subcutaneous injections. These injections were repeated at 20-days intervals and blood samples (40 ml) were taken from the jugular vein 10 days after the boosts for the evaluation of the antisera title. After each four boosts a great bleeding was done by the same route. Approximately 500 ml of serum were obtained in each bleeding per animal. The antisera were evaluated by the human thyrotropin RIA developed at IPEN laboratories employing reagents provided by NIDDKD, USA. These evaluations referred to the determination of the antisera title and of the ideal concentration of carrier IgG, to the study of the kinetic of precipitation and to the confirmation of the inexistent cross-reactivity with human IgG, in comparison with a reference antiserum of know precipitation characteristics supplied by the Radioassay System Laboratories. Approximately 3,6 l of antiserum (sheep anti-rabbit IgG serum) were produced from the four sheep, which presented title and precipitation characteristics very similar to those exhibited by the imported commercial product, even presenting higher titles. The results obtained in this work indicated that it was created enough experience for the production of this biological reagent for RIA, that could be done integrally in the country in greater scale, and at a very reduced cost. (author). 81 refs, 36 figs, 33 tabs

  2. Dynamics evaluation of total IgG, IgG1 and IgG2a in the serum of mice immunized with radioattenuated paracoccidioides brasiliensis yeast cells