WorldWideScience

Sample records for b-cell regulatory molecule

  1. Influence of drug molecules on regulatory B cells.

    Science.gov (United States)

    Amrouche, Kahina; Jamin, Christophe

    2017-11-01

    By their suppressive functions, regulatory B (Breg) cells are considered as key elements in the control and development of various disease states. Many signals can induce Bregs in vivo and in vitro and often from heterogeneous populations. Several specific signals delivered in a timely immunological context contribute to the establishment of Bregs. These are endogenous and physiological signals or stimuli, widely discussed in the literature participating in the establishment of an effective immune response. However, exogenous signals, much less clearly identified can also be considered as Bregs inducers. These extrinsic signals are capable of directly or indirectly influencing the suppressive capacity of Bregs, but also their expansion and functional restoration in its absence. Faced with the excitement generated by the development of processes favoring the expansion of Bregs in mice for therapeutic purposes, the challenge today is to extrapolate such approaches in humans. This perspective may already be in effect. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. APS, an adaptor molecule containing PH and SH2 domains, has a negative regulatory role in B cell proliferation

    International Nuclear Information System (INIS)

    Iseki, Masanori; Kubo-Akashi, Chiyomi; Kwon, Sang-Mo; Yamaguchi, Akiko; Takatsu, Kiyoshi; Takaki, Satoshi

    2005-01-01

    Adaptor molecule containing PH and SH2 domains (APS) is an intracellular adaptor protein that forms part of an adaptor family along with Lnk and SH2-B. APS transcripts are expressed in various tissues including brain, kidney, and muscle, as well as in splenic B cells but not in T cells. We investigated the functions of APS in B cell development and activation by generating APS-transgenic (APS-Tg) mice that overexpressed APS in lymphocytes. The number of B-1 cells in the peritoneal cavity was reduced in APS-Tg mice, as were B-2 cells in the spleen. B cell development in the bone marrow was partially impaired at the transition stage from proliferating large pre-B to small pre-B cells. B cell proliferation induced by B cell receptor (BCR) crosslinking but not by other B cell mitogens was also impaired in APS-Tg mice. APS co-localized with BCR complexes and filamentous actin in activated APS-Tg B cells. Thus, APS appears to play novel negative regulatory roles in BCR signaling, actin reorganization pathways, and control of compartment sizes of B-lineage cells

  3. Various domains of the B-cell regulatory molecule CD72 has diverged at different rates in mammals

    DEFF Research Database (Denmark)

    Petersen, Cathrine Bie; Hillig, Ann-Britt Nygaard; Fredholm, Merete

    2007-01-01

    72 has been shown to be a negatively regulating BCR co-receptor. We isolated and sequenced three porcine CD72 transcript variants. Using a pig radiation hybrid panel we found the porcien CD72 gene to be located on chromosome 1q21-28 in a region syntenic to human chromosome 9. The porcine CD72 gene......We report the cloning of the porcine B-cell co-receptor CD72, as well as genomic mapping and examination of transcription. The B-cell receptor (BCR) complex mediates signalling upon antigen recognition by the membrane bound BCR. Several co-receptors modulate this signal positively or negatively. CD...

  4. Human regulatory B cells control the TFH cell response.

    Science.gov (United States)

    Achour, Achouak; Simon, Quentin; Mohr, Audrey; Séité, Jean-François; Youinou, Pierre; Bendaoud, Boutahar; Ghedira, Ibtissem; Pers, Jacques-Olivier; Jamin, Christophe

    2017-07-01

    Follicular helper T (T FH ) cells support terminal B-cell differentiation. Human regulatory B (Breg) cells modulate cellular responses, but their control of T FH cell-dependent humoral immune responses is unknown. We sought to assess the role of Breg cells on T FH cell development and function. Human T cells were polyclonally stimulated in the presence of IL-12 and IL-21 to generate T FH cells. They were cocultured with B cells to induce their terminal differentiation. Breg cells were included in these cultures, and their effects were evaluated by using flow cytometry and ELISA. B-cell lymphoma 6, IL-21, inducible costimulator, CXCR5, and programmed cell death protein 1 (PD-1) expressions increased on stimulated human T cells, characterizing T FH cell maturation. In cocultures they differentiated B cells into CD138 + plasma and IgD - CD27 + memory cells and triggered immunoglobulin secretions. Breg cells obtained by Toll-like receptor 9 and CD40 activation of B cells prevented T FH cell development. Added to T FH cell and B-cell cocultures, they inhibited B-cell differentiation, impeded immunoglobulin secretions, and expanded Foxp3 + CXCR5 + PD-1 + follicular regulatory T cells. Breg cells modulated IL-21 receptor expressions on T FH cells and B cells, and their suppressive activities involved CD40, CD80, CD86, and intercellular adhesion molecule interactions and required production of IL-10 and TGF-β. Human Breg cells control T FH cell maturation, expand follicular regulatory T cells, and inhibit the T FH cell-mediated antibody secretion. These novel observations demonstrate a role for the Breg cell in germinal center reactions and suggest that deficient activities might impair the T FH cell-dependent control of humoral immunity and might lead to the development of aberrant autoimmune responses. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  5. Galectin-1 is required for the regulatory function of B cells.

    Science.gov (United States)

    Alhabbab, R; Blair, P; Smyth, L A; Ratnasothy, K; Peng, Q; Moreau, A; Lechler, R; Elgueta, R; Lombardi, G

    2018-02-09

    Galectin-1 (Gal-1) is required for the development of B cells in the bone marrow (BM), however very little is known about the contribution of Gal-1 to the development of B cell regulatory function. Here, we report an important role for Gal-1 in the induction of B cells regulatory function. Mice deficient of Gal-1 (Gal-1 -/- ) showed significant loss of Transitional-2 (T2) B cells, previously reported to include IL-10 + regulatory B cells. Gal-1 -/- B cells stimulated in vitro via CD40 molecules have impaired IL-10 and Tim-1 expression, the latter reported to be required for IL-10 production in regulatory B cells, and increased TNF-α expression compared to wild type (WT) B cells. Unlike their WT counterparts, T2 and T1 Gal-1 -/- B cells did not suppress TNF-α expression by CD4 + T cells activated in vitro with allogenic DCs (allo-DCs), nor were they suppressive in vivo, being unable to delay MHC-class I mismatched skin allograft rejection following adoptive transfer. Moreover, T cells stimulated with allo-DCs show an increase in their survival when co-cultured with Gal-1 -/- T2 and MZ B cells compared to WT T2 and MZ B cells. Collectively, these data suggest that Gal-1 contributes to the induction of B cells regulatory function.

  6. The regulatory roles of B cell subsets in transplantation.

    Science.gov (United States)

    Chu, Zhulang; Zou, Weilong; Xu, Yanan; Sun, Qiquan; Zhao, Yong

    2018-02-01

    B cells mediate allograft rejection through antigen presentation, and production of cytokines and antibodies. More and more immunosuppressive agents specifically targeting B cells and plasma cells have been applied in clinical transplantation. However, recent studies have indicated the regulatory roles of B cells. Therefore, it is vital to clarify the different effects of B cell subsets in organ transplantation so that we can completely understand the diverse functions of B cells in transplantation. Areas covered: This review focuses on the regulatory roles of B cells in transplantation. B cell subsets with immune modulation and factors mediating immunosuppressive functions of regulatory B (Breg) cells were analyzed. Therapies targeting B cells and the application of B cells for transplant tolerance induction were discussed. Expert commentary: Besides involving rejection, B cells could also play regulatory roles in transplantation. Breg cells and the related markers may be used to predict the immune tolerant state in transplant recipients. New therapeutic strategies targeting B cells should be explored to promote tolerance induction with less impact on the host's protective immunity in organ transplanted patients.

  7. Regulatory T cells and B cells: implication on autoimmune diseases

    OpenAIRE

    Wang, Ping; Zheng, Song Guo

    2013-01-01

    The regulatory T (Treg) cells play an important role in the maintenance of homeostasis and the prevention of autoimmune diseases. Although most studies are focusing on the role of Treg cells in T cells and T cells-mediated diseases, these cells also directly affect B cells and other non-T cells. This manuscript updates the role of Treg cells on the B cells and B cell-mediated diseases. In addition, the mechanisms whereby Treg cells suppress B cell responses have been discussed.

  8. B cell subsets and dysfunction of regulatory B cells in IgG4-related diseases and primary Sjögren’s syndrome: the similarities and differences

    Science.gov (United States)

    2014-01-01

    Introduction IgG4-related disease (IgG4-RD) is a multisystem-involved autoimmune disease. Abnormally activated and differentiated B cells may play important roles. Regulatory B cells (Breg) are newly defined B cell subgroups with immunosuppressive functions. In this study, we investigated the differences of B cell subsets, the expressions of co-stimulatory molecules on B cells, and the function of Breg cells in patients with IgG4-RD, primary Sjögren’s syndrome (pSS) as well as in healthy controls (HC). Methods Newly diagnosed IgG4-RD patients (n = 48) were enrolled, 38 untreated pSS patients and 30 healthy volunteers were recruited as disease and healthy controls. To analyze B cell subsets and B cell activity, PBMCs were surface stained and detected by flow cytometry. The function of Breg cells was tested by coculturing isolated CD19 + CD24hiCD38hi Breg cells with purified CD4 + CD25- T cells. Serum cytokines were measured by ELISA and cytometric bead array. Relationship between clinical data and laboratory findings were analyzed as well. Results Compared with pSS patients and HC, IgG4-RD patients had a lower frequency of peripheral Breg cells. Interestingly, CD19 + CD24-CD38hi B cell subsets were significantly higher in peripheral B cells from IgG4-RD patients than in pSS patients and HC, which correlated with serum IgG4 levels. The expression of BAFF-R and CD40 on B cells was significantly lower in IgG4-RD patients compared with those in pSS patients and HC. Unlike HC, Breg cells from pSS patients lacked suppressive functions. Conclusions B cells in patients with IgG4-RD and pSS display a variety of abnormalities, including disturbed B cell subpopulations, abnormal expression of key signaling molecules, co-stimulatory molecules, and inflammatory cytokines. In addition, a significantly increased B cell subset, CD19 + CD24-CD38hi B cells, may play an important role in the pathogenesis of IgG4-RD. PMID:24887143

  9. Defective Circulating Regulatory B Cells in Patients with Dilated Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Jiao Jiao

    2018-03-01

    Full Text Available Background/Aims: Newly identified IL-10-producing regulatory B cells (Bregs have been shown to play an important role in the suppression of immune responses. Chronic immune activation participates in the pathogenesis of dilated cardiomyopathy (DCM but whether Bregs are involved in its development remains unclear. We aimed to investigate the circulating frequency and function of Bregs in DCM. Methods: In total, 35 DCM patients (20 men and 15 women and 44 healthy controls (23 men and 21 women were included in the experiment, and the frequency of Bregs was detected using flow cytometry. Results: According to our results, the frequency of circulating IL-10-producing Bregs was significantly lower in DCM patients compared with healthy controls. Furthermore, the CD24hiCD27+ B cell subset in which IL-10-producing Bregs were mainly enriched from DCM patients showed impaired IL-10 expression and a decreased ability to suppress the TNF-α production of CD4+CD25- Tconv cells and to maintain Tregs differentiation. Correlation analysis showed that the frequency of IL-10-producing Bregs and the suppressive function of CD24hiCD27+ B cells were positively correlated with left ventricular ejection fraction and negatively correlated with NT-proBNP in DCM patients. Conclusions: In conclusion, the reduced frequency and impaired functions suggest a potential role of Bregs in the development of DCM.

  10. Cloning of B cell-specific membrane tetraspanning molecule BTS possessing B cell proliferation-inhibitory function.

    Science.gov (United States)

    Suenaga, Tadahiro; Arase, Hisashi; Yamasaki, Sho; Kohno, Masayuki; Yokosuka, Tadashi; Takeuchi, Arata; Hattori, Takamichi; Saito, Takashi

    2007-11-01

    Lymphocyte proliferation is regulated by signals through antigen receptors, co-stimulatory receptors, and other positive and negative modulators. Several membrane tetraspanning molecules are also involved in the regulation of lymphocyte growth and death. We cloned a new B cell-specific tetraspanning (BTS) membrane molecule, which is similar to CD20 in terms of expression, structure and function. BTS is specifically expressed in the B cell line and its expression is increased after the pre-B cell stage. BTS is expressed in intracellular granules and on the cell surface. Overexpression of BTS in immature B cell lines induces growth retardation through inhibition of cell cycle progression and cell size increase without inducing apoptosis. This inhibitory function is mediated predominantly by the N terminus of BTS. The development of mature B cells is inhibited in transgenic mice expressing BTS, suggesting that BTS is involved in the in vivo regulation of B cells. These results indicate that BTS plays a role in the regulation of cell division and B cell growth.

  11. A role for adhesion molecules in contact-dependent T help for B cells

    DEFF Research Database (Denmark)

    Owens, T

    1991-01-01

    The role of cell contact in T-dependent B cell activation was examined. Small resting B cells from C57BL/6 mice were cultured with CBA-derived, non-alloreactive cloned T helper cells in anti-T cell receptor V beta 8-coated microwells. This induced polyclonal B cell activation to enter cell cycle...... that continued cell contact involving adhesion/accessory molecules induces B cells to proliferate and to respond to T cell lymphokines. A signaling role for cell interaction molecules on B cells is proposed, similar to the role of these and analogous molecules on T cells....

  12. B cell lymphomas express CX3CR1 a non-B cell lineage adhesion molecule

    DEFF Research Database (Denmark)

    Andreasson, U.; Ek, S.; Merz, H.

    2008-01-01

    normally is not expressed on B cells, is expressed both at the mRNA and protein level in several subtypes of lymphoma. CX3CR1 has also shown to be involved in the homing to specific tissues that express the ligand, CX3CL1, in breast and prostate cancer and may thus be involved in dissemination of lymphoma......To study the differential expression of cell membrane-bound receptors and their potential role in growth and/or survival of the tumor cells, highly purified follicular lymphoma cells were analyzed, using gene expression analysis, and compared to non-malignant B cell populations. Filtering...... the genome for overexpressed genes coding for cell membrane-bound proteins/receptors resulted in a hit list of 27 identified genes. Among these, we have focused on the aberrant over expression of CX3CR1, in different types of B cell lymphoma, as compared to non-malignant B cells. We show that CX3CR1, which...

  13. BIP induces mice CD19(hi) regulatory B cells producing IL-10 and highly expressing PD-L1, FasL.

    Science.gov (United States)

    Tang, Youfa; Jiang, Qing; Ou, Yanghui; Zhang, Fan; Qing, Kai; Sun, Yuanli; Lu, Wenjie; Zhu, Huifen; Gong, Feili; Lei, Ping; Shen, Guanxin

    2016-01-01

    Many studies have shown that B cells possess a regulatory function in mouse models of autoimmune diseases. Regulatory B cells can modulate immune response through many types of molecular mechanisms, including the production of IL-10 and the expression of PD-1 Ligand and Fas Ligand, but the microenvironmental factors and mechanisms that induce regulatory B cells have not been fully identified. BIP (binding immunoglobulin protein), a member of the heat shock protein 70 family, is a type of evolutionarily highly conserved protein. In this article, we have found that IL-10(+), PD-L1(hi) and FasL(hi) B cells are discrete cell populations, but enriched in CD19(hi) cells. BIP can induce IL-10-producing splenic B cells, IL-10 secretion and B cells highly expressing PD-L1 and FasL. CD40 signaling acts in synergy with BIP to induce regulatory B cells. BIP increased surface CD19 molecule expression intensity and IL-10(+), PD-L1(hi) and FasL(hi) B cells induced by BIP share the CD19(hi) phenotype. Furthermore, B cells treated with BIP and anti-CD40 can lead to suppression of T cell proliferation and the effect is partially IL-10-dependent and mainly BIP-induced. Taken together, our findings identify a novel function of BIP in the induction of regulatory B cells and add a new reason for the therapy of autoimmune disorders or other inflammatory conditions. Copyright © 2015. Published by Elsevier Ltd.

  14. Transitional-2 B cells acquire regulatory function during tolerance induction and contribute to allograft survival.

    Science.gov (United States)

    Moreau, Aurélie; Blair, Paul A; Chai, Jian-Guo; Ratnasothy, Kulachelvy; Stolarczyk, Emilie; Alhabbab, Rowa; Rackham, Chloe L; Jones, Peter M; Smyth, Lesley; Elgueta, Raul; Howard, Jane K; Lechler, Robert I; Lombardi, Giovanna

    2015-03-01

    In humans, tolerance to renal transplants has been associated with alterations in B-cell gene transcription and maintenance of the numbers of circulating transitional B cells. Here, we use a mouse model of transplantation tolerance to investigate the contribution of B cells to allograft survival. We demonstrate that transfer of B cells from mice rendered tolerant to MHC class I mismatched skin grafts can prolong graft survival in a dose-dependent and antigen-specific manner to a degree similar to that afforded by graft-specific regulatory T (Treg) cells. Tolerance in this model was associated with an increase in transitional-2 (T2) B cells. Only T2 B cells from tolerized mice, not naïve T2 nor alloantigen experienced T2, were capable of prolonging skin allograft survival, and suppressing T-cell activation. Tolerized T2 B cells expressed lower levels of CD86, increased TIM-1, and demonstrated a preferential survival in vivo. Furthermore, we demonstrate a synergistic effect between tolerized B cells and graft-specific Treg cells. IL-10 production by T2 B cells did not contribute to tolerance, as shown by transfer of B cells from IL-10(-/-) mice. These results suggest that T2 B cells in tolerant patients may include a population of regulatory B cells that directly inhibit graft rejection. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Characterization of Regulatory B Cells in Graves' Disease and Hashimoto's Thyroiditis

    DEFF Research Database (Denmark)

    Kristensen, Birte; Hegedüs, Laszlo; Lundy, Steven K

    2015-01-01

    A hallmark of regulatory B cells is IL-10 production, hence their designation as IL-10+ B cells. Little is known about the ability of self-antigens to induce IL-10+ B cells in Graves' disease (GD), Hashimoto's thyroiditis (HT), or other autoimmune disease. Here we pulsed purified B cells from 12 HT...... patients, 12 GD patients, and 12 healthy donors with the thyroid self-antigen, thyroglobulin (TG) and added the B cells back to the remaining peripheral blood mononuclear cells (PBMCs). This procedure induced IL-10+ B-cell differentiation in GD. A similar tendency was observed in healthy donors...... and correlated with free T3 levels in GD patients. IL-10+ B cells from both patient groups displayed CD25 or TIM-1 more frequently than did those from healthy donors. B-cell expression of two surface marker combinations previously associated with regulatory B-cell functions, CD24hiCD38hi and CD27+CD43+, did...

  16. Adhesion molecule profiles of B-cell non-Hodgkin's lymphomas in the leukemic phase

    Directory of Open Access Journals (Sweden)

    D.M. Matos

    2006-10-01

    Full Text Available We evaluated the expression of 10 adhesion molecules on peripheral blood tumor cells of 17 patients with chronic lymphocytic leukemia, 17 with mantle-cell lymphoma, and 13 with nodal or splenic marginal B-cell lymphoma, all in the leukemic phase and before the beginning of any therapy. The diagnosis of B-cell non-Hodgkin's lymphomas was based on cytological, histological, immunophenotypic, and molecular biology methods. The mean fluorescence intensity of the adhesion molecules in tumor cells was measured by flow cytometry of CD19-positive cells and differed amongst the types of lymphomas. Comparison of chronic lymphocytic leukemia and mantle-cell lymphoma showed that the former presented a higher expression of CD11c and CD49c, and a lower expression of CD11b and CD49d adhesion molecules. Comparison of chronic lymphocytic leukemia and marginal B-cell lymphoma showed that the former presented a higher expression of CD49c and a lower expression of CD11a, CD11b, CD18, CD49d, CD29, and CD54. Finally, comparison of mantle-cell lymphoma and marginal B-cell lymphoma showed that marginal B-cell lymphoma had a higher expression of CD11a, CD11c, CD18, CD29, and CD54. Thus, the CD49c/CD49d pair consistently demonstrated a distinct pattern of expression in chronic lymphocytic leukemia compared with mantle-cell lymphoma and marginal B-cell lymphoma, which could be helpful for the differential diagnosis. Moreover, the distinct profiles of adhesion molecules in these diseases may be responsible for their different capacities to invade the blood stream.

  17. Regulatory B cells: an exciting target for future therapeutics in transplantation

    Directory of Open Access Journals (Sweden)

    Alexandre eNouël

    2014-01-01

    Full Text Available Transplantation is the preferred treatment for most end-stage solid organ diseases. Despite potent immunosuppressive agents, chronic rejection remains a real problem in transplantation. For many years, the predominant immunological focus of research into transplant rejection has been T cells. The pillar of immunotherapy in clinical practice is T cell-directed, which efficiently prevents acute T cell-mediated allograft rejection. However, the root of late allograft failure is chronic rejection and the humoral arm of the immune response now emerges as an important factor in transplantation. Thus, the potential effects of Abs and B cell infiltrates on transplants have cast B cells as major actors in late graft rejection. Consequently, a number of recent drugs target either B cells or plasma cells. However, immunotherapies, such as the anti-CD20 B cell-depleting Ab, can generate deleterious effects on the transplant, likely due to the deletion of beneficial population. The positive contribution of regulatory B (Breg cells -or B10 cells- has been reported in the case of transplantation, mainly in mice models and highlights the primordial role that some populations of B cells can play in graft tolerance. Yet, this regulatory aspect remains poorly characterized in clinical transplantation. Thus, total B cell depletion treatments should be avoided and novel approaches should be considered that manipulate the different B cell subsets. This article provides an overview of the current knowledge on the link between Breg cells and grafts, and reports a number of data advising Breg cells as a new target for future therapeutic approaches.

  18. Diversity of gut microflora is required for the generation of B cell with regulatory properties in a skin graft model.

    Science.gov (United States)

    Alhabbab, R; Blair, P; Elgueta, R; Stolarczyk, E; Marks, E; Becker, P D; Ratnasothy, K; Smyth, L; Safinia, N; Sharif-Paghaleh, E; O'Connell, S; Noelle, R J; Lord, G M; Howard, J K; Spencer, J; Lechler, R I; Lombardi, G

    2015-06-25

    B cells have been reported to promote graft rejection through alloantibody production. However, there is growing evidence that B cells can contribute to the maintenance of tolerance. Here, we used a mouse model of MHC-class I mismatched skin transplantation to investigate the contribution of B cells to graft survival. We demonstrate that adoptive transfer of B cells prolongs skin graft survival but only when the B cells were isolated from mice housed in low sterility "conventional" (CV) facilities and not from mice housed in pathogen free facilities (SPF). However, prolongation of skin graft survival was lost when B cells were isolated from IL-10 deficient mice housed in CV facilities. The suppressive function of B cells isolated from mice housed in CV facilities correlated with an anti-inflammatory environment and with the presence of a different gut microflora compared to mice maintained in SPF facilities. Treatment of mice in the CV facility with antibiotics abrogated the regulatory capacity of B cells. Finally, we identified transitional B cells isolated from CV facilities as possessing the regulatory function. These findings demonstrate that B cells, and in particular transitional B cells, can promote prolongation of graft survival, a function dependent on licensing by gut microflora.

  19. Diversity of gut microflora is required for the generation of B cell with regulatory properties in a skin graft model

    Science.gov (United States)

    Alhabbab, R.; Blair, P.; Elgueta, R.; Stolarczyk, E.; Marks, E.; Becker, P. D.; Ratnasothy, K.; Smyth, L.; Safinia, N.; Sharif-Paghaleh, E.; O’Connell, S.; Noelle, R. J.; Lord, G. M.; Howard, J. K.; Spencer, J.; Lechler, R. I.; Lombardi, G.

    2015-01-01

    B cells have been reported to promote graft rejection through alloantibody production. However, there is growing evidence that B cells can contribute to the maintenance of tolerance. Here, we used a mouse model of MHC-class I mismatched skin transplantation to investigate the contribution of B cells to graft survival. We demonstrate that adoptive transfer of B cells prolongs skin graft survival but only when the B cells were isolated from mice housed in low sterility “conventional” (CV) facilities and not from mice housed in pathogen free facilities (SPF). However, prolongation of skin graft survival was lost when B cells were isolated from IL-10 deficient mice housed in CV facilities. The suppressive function of B cells isolated from mice housed in CV facilities correlated with an anti-inflammatory environment and with the presence of a different gut microflora compared to mice maintained in SPF facilities. Treatment of mice in the CV facility with antibiotics abrogated the regulatory capacity of B cells. Finally, we identified transitional B cells isolated from CV facilities as possessing the regulatory function. These findings demonstrate that B cells, and in particular transitional B cells, can promote prolongation of graft survival, a function dependent on licensing by gut microflora. PMID:26109230

  20. Signaling through intercellular adhesion molecule 1 (ICAM-1) in a B cell lymphoma line

    DEFF Research Database (Denmark)

    Holland, J; Owens, T

    1997-01-01

    Intercellular adhesion molecule 1 (ICAM-1) (CD54) is an adhesion molecule of the immunoglobulin superfamily. The interaction between ICAM-1 on B lymphocytes and leukocyte function-associated antigen 1 on T cells plays a major role in several aspects of the immune response, including T-dependent B...... cell activation. While it was originally believed that ICAM-1 played a purely adhesive role, recent evidence suggests that it can itself transduce biochemical signals. We demonstrate that cross-linking of ICAM-1 results in the up-regulation of class II major histocompatibility complex, and we...... investigate the biochemical mechanism for the signaling role of ICAM-1. We show that cross-linking of ICAM-1 on the B lymphoma line A20 induces an increase in tyrosine phosphorylation of several cellular proteins, including the Src family kinase p53/p56(lyn). In vitro kinase assays showed that Lyn kinase...

  1. Distinct cytokines balance the development of regulatory T cells and interleukin-10-producing regulatory B cells

    Czech Academy of Sciences Publication Activity Database

    Holáň, Vladimír; Zajícová, Alena; Javorková, Eliška; Trošan, Peter; Chudíčková, Milada; Pavlíková, M.; Krulová, Magdaléna

    2014-01-01

    Roč. 141, č. 4 (2014), s. 577-586 ISSN 0019-2805 R&D Projects: GA MZd(CZ) NT14102; GA ČR(CZ) GAP301/11/1568; GA ČR GAP304/11/0653 Institutional support: RVO:68378041 Keywords : Autoregulation * B cells * Cytokines Subject RIV: FF - HEENT, Dentistry Impact factor: 3.795, year: 2014

  2. Regulatory role for the memory B cell as suppressor-inducer of feedback control

    International Nuclear Information System (INIS)

    Kennedy, M.W.; Thomas, D.B.

    1983-01-01

    A regulatory role is proposed for the antigen-responsive B cell, as suppressor-inducer of feedback control during the secondary response in vivo. In a double adoptive transfer of memory cells primed to a thymus-dependent antigen from one irradiated host to another, antigen-specific suppressors are generated after a critical time in the primary recipient, able to entirely ablate a secondary anti-hapten response. Positive cell selection in the fluorescence-activated cell sorter confirmed that suppression was mediated by an Lyt-2+ T cell; however, positively selected B cells were also inhibitory and able to induce suppressors in a carrier-specific manner: B hapten induced suppressors in a carrier-primed population, and B carrier induced suppressors in a hapten-carrier population. At the peak of the antibody response in the primary host, memory B cells and their progeny were unable to differentiate further to plasma cells due to their intrinsic suppressor-inducer activity, but this autoregulatory circuit could be severed by adoptive transfer to carrier-primed, X-irradiated recipients

  3. Cis-regulatory somatic mutations and gene-expression alteration in B-cell lymphomas.

    Science.gov (United States)

    Mathelier, Anthony; Lefebvre, Calvin; Zhang, Allen W; Arenillas, David J; Ding, Jiarui; Wasserman, Wyeth W; Shah, Sohrab P

    2015-04-23

    With the rapid increase of whole-genome sequencing of human cancers, an important opportunity to analyze and characterize somatic mutations lying within cis-regulatory regions has emerged. A focus on protein-coding regions to identify nonsense or missense mutations disruptive to protein structure and/or function has led to important insights; however, the impact on gene expression of mutations lying within cis-regulatory regions remains under-explored. We analyzed somatic mutations from 84 matched tumor-normal whole genomes from B-cell lymphomas with accompanying gene expression measurements to elucidate the extent to which these cancers are disrupted by cis-regulatory mutations. We characterize mutations overlapping a high quality set of well-annotated transcription factor binding sites (TFBSs), covering a similar portion of the genome as protein-coding exons. Our results indicate that cis-regulatory mutations overlapping predicted TFBSs are enriched in promoter regions of genes involved in apoptosis or growth/proliferation. By integrating gene expression data with mutation data, our computational approach culminates with identification of cis-regulatory mutations most likely to participate in dysregulation of the gene expression program. The impact can be measured along with protein-coding mutations to highlight key mutations disrupting gene expression and pathways in cancer. Our study yields specific genes with disrupted expression triggered by genomic mutations in either the coding or the regulatory space. It implies that mutated regulatory components of the genome contribute substantially to cancer pathways. Our analyses demonstrate that identifying genomically altered cis-regulatory elements coupled with analysis of gene expression data will augment biological interpretation of mutational landscapes of cancers.

  4. Perioperative dynamic alterations in peripheral regulatory T and B cells in patients with hepatocellular carcinoma

    Directory of Open Access Journals (Sweden)

    Chen Tianxiang

    2012-01-01

    Full Text Available Abstract Background Intratumoral and circulating regulatory T cells (Tregs have been shown to be critical in the pathogenesis of hepatocellular carcinoma (HCC. However there is limited knowledge on the alterations of regulatory B cells (Bregs. We here investigated perioperative dynamic alterations of peripheral circulating Tregs and Bregs in HCC patients to reveal the relationship between regulatory lymphocytes and its clinical implications. Methods 36 patients with HCC, 6 with chronic hepatitis B infection and 10 healthy donors were enrolled for this study. Frequencies of peripheral Tregs and Bregs were measured by flow cytometry with antibodies against CD4, CD25, CD127, CD19 and IL-10 before, and after radical surgery. Then, clinical informatics of HCC patients was achieved through Digital Evaluation Score System (DESS for the assessment of disease severity. Finally, we analysed correlations between digitalized clinical features and kinetics of circulating regulatory lymphocytes. Results Level of circulating CD4+CD25+CD127- Tregs in HCC patients was significantly lower than that in healthy donors and patients with chronic hepatitis B infection before surgery, but was increased after surgery. Preoperative level of CD19+ IL-10+ Bregs in HCC patients was also significantly lower than the other groups. However it dramatically was elevated right after surgery and remained elevated compared to controls (about 7 days after surgery, P = 0.04. Frequency of circulating Tregs was correlated with circulating leukocytes, ferritin, and clinical features suggesting tumor aggressiveness including portal vein thrombosis, hepatic vein involvement and advanced clinical stages. Frequency of circulating Bregs was associated with Hepatitis B e Antigen (HBeAg and Hepatitis B virus (HBV DNA copy number. In addition, DESS was significantly and positively correlated with other staging systems. Conclusion Frequencies of peripheral Tregs and Bregs in HCC patients

  5. Human CD40 ligand-expressing type 3 innate lymphoid cells induce IL-10-producing immature transitional regulatory B cells.

    Science.gov (United States)

    Komlósi, Zsolt I; Kovács, Nóra; van de Veen, Willem; Kirsch, Anna Isabella; Fahrner, Heinz Benedikt; Wawrzyniak, Marcin; Rebane, Ana; Stanic, Barbara; Palomares, Oscar; Rückert, Beate; Menz, Günter; Akdis, Mübeccel; Losonczy, György; Akdis, Cezmi A

    2017-09-20

    Type 3 innate lymphoid cells (ILC3s) are involved in maintenance of mucosal homeostasis; however, their role in immunoregulation has been unknown. Immature transitional regulatory B (itBreg) cells are innate-like B cells with immunosuppressive properties, and the in vivo mechanisms by which they are induced have not been fully clarified. We aimed to investigate the ILC3-B-cell interaction that probably takes place in human tonsils. ILC3s were isolated from peripheral blood and palatine tonsils, expanded, and cocultured with naive B cells. Tonsillar ILC3s and regulatory B cells were visualized with immunofluorescence histology. ILC3 frequencies were measured in tonsil tissue of allergic and nonallergic patients and in peripheral blood of allergic asthmatic patients and healthy control subjects. A mutually beneficial relationship was revealed between ILC3s and B cells: ILC3s induced IL-15 production in B cells through B cell-activating factor receptor, whereas IL-15, a potent growth factor for ILC3s, induced CD40 ligand (CD40L) expression on circulating and tonsillar ILC3s. IL-15-activated CD40L + ILC3s helped B-cell survival, proliferation, and differentiation of IL-10-secreting, PD-L1-expressing functional itBreg cells in a CD40L- and B cell-activating factor receptor-dependent manner. ILC3s and regulatory B cells were in close connection with each other in palatine tonsils. ILC3 frequency was reduced in tonsil tissue of allergic patients and in peripheral blood of allergic asthmatic patients. Human CD40L + ILC3s provide innate B-cell help and are involved in an innate immunoregulatory mechanism through induction of itBreg cell differentiation, which takes place in palatine tonsils in vivo. This mechanism, which can contribute to maintenance of immune tolerance, becomes insufficient in allergic diseases. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  6. BAFF promotes regulatory T-cell apoptosis and blocks cytokine production by activating B cells in primary biliary cirrhosis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bo; Hu, Mintao [Department of Hepatology, Wuxi Infectious Diseases Hospital, Wuxi, Jiangsu (China); Zhang, Peng [Nanjing Medical University, Nanjing, Jiangsu (China); Cao, Hong [Department of Hepatology, Wuxi Infectious Diseases Hospital, Wuxi, Jiangsu (China); Wang, Yongzhen [The Second Hospital of Nanjing, Nanjing, Jiangsu (China); Wang, Zheng; Su, Tingting [Department of Hepatology, Wuxi Infectious Diseases Hospital, Wuxi, Jiangsu (China)

    2013-05-10

    Primary biliary cirrhosis (PBC) is a chronic and slowly progressive cholestatic liver disease of autoimmune etiology. A number of questions regarding its etiology are unclear. CD4+CD25+ regulatory T cells (Tregs) play a critical role in self-tolerance and, for unknown reasons, their relative number is reduced in PBC patients. B-cell-activating factor (BAFF) is a key survival factor during B-cell maturation and its concentration is increased in peripheral blood of PBC patients. It has been reported that activated B cells inhibit Treg cell proliferation and there are no BAFF receptors on Tregs. Therefore, we speculated that excessive BAFF may result in Treg reduction via B cells. To prove our hypothesis, we isolated Tregs and B cells from PBC and healthy donors. BAFF and IgM concentrations were then analyzed by ELISA and CD40, CD80, CD86, IL-10, and TGF-β expression in B cells and Tregs were measured by flow cytometry. BAFF up-regulated CD40, CD80, CD86, and IgM expression in B cells. However, BAFF had no direct effect on Treg cell apoptosis and cytokine secretion. Nonetheless, we observed that BAFF-activated B cells could induce Treg cell apoptosis and reduce IL-10 and TGF-β expression. We also showed that BAFF-activated CD4+ T cells had no effect on Treg apoptosis. Furthermore, we verified that bezafibrate, a hypolipidemic drug, can inhibit BAFF-induced Treg cell apoptosis. In conclusion, BAFF promotes Treg cell apoptosis and inhibits cytokine production by activating B cells in PBC patients. The results of this study suggest that inhibition of BAFF activation is a strategy for PBC treatment.

  7. Quantitative and qualitative analysis of regulatory T cells in B cell chronic lymphocytic leukemia.

    Science.gov (United States)

    Mpakou, Vassiliki E; Ioannidou, Heleni-Dikaia; Konsta, Eugene; Vikentiou, Myrofora; Spathis, Aris; Kontsioti, Frieda; Kontos, Christos K; Velentzas, Athanassios D; Papageorgiou, Sotiris; Vasilatou, Diamantina; Gkontopoulos, Konstantinos; Glezou, Irene; Stavroulaki, Georgia; Mpazani, Efthimia; Kokkori, Stella; Kyriakou, Elias; Karakitsos, Petros; Dimitriadis, George; Pappa, Vasiliki

    2017-09-01

    Accumulated data indicate a significant role of T cell dysfunction in the pathogenesis of chronic lymphocytic leukemia. In CLL, regulatory T cells are significantly higher and show lower apoptotic levels compared to healthy donors. We demonstrate that CLL derived CD4 + CD25 - CD127 - and CD4 + CD25 low CD127 - subpopulations share a common immunophenotypic profile with conventional Tregs and are associated with advanced stage disease. We further provide evidence that the increased number of Tregs contributes indirectly to the proliferation of the CLL clone, by suppressing the proliferation of Teffs which in turn suppress CLL cells. These data are further supported by our observations that CLL derived Tregs appear rather incapable of inducing apoptosis of both normal B cells and CLL cells, in contrast to normal Tregs, suggesting an immunoediting effect of CLL cells on Tregs which negatively affects the functionality of the latter and contributes to the failure of Tregs in CLL to efficiently eliminate the abnormal clone. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Circulating regulatory B cell subsets in patients with neuromyelitis optica spectrum disorders.

    Science.gov (United States)

    Han, Jinming; Sun, Li; Wang, Zhongkun; Fan, Xueli; Wang, Lifang; Song, Yang-Yang; Zhu, Jie; Jin, Tao

    2017-07-01

    This study analyzed the populations of three different subsets of regulatory B cells (Bregs) in the peripheral blood mononuclear cells (PBMCs) of patients with neuromyelitis optica spectrum disorders (NMOSDs) and explored the relationship between the changes in these subsets of Bregs and the severity of NMOSD. A total of 22 patients with relapsed NMOSDs before treatment were recruited in our study, along with 20 age and gender-matched healthy controls, from May 2015 to March 2016. The percentages and numbers for three different subsets of Bregs including the CD19 + CD24 hi CD38 hi , CD19 + CD24 hi CD27 + , and CD19 + CD5 + CD1d hi populations were evaluated in parallel by flow cytometry. Afterwards, correlations between the change of three different subsets of Bregs and disease severity were analyzed. We found significantly lower percentages of CD19 + CD24 hi CD38 hi and CD19 + CD5 + CD1d hi Bregs in NMOSDs patients than in healthy individuals. In contrast, the CD19 + CD24 hi CD27 + Bregs population was significantly higher in NMOSDs patients than in healthy individuals. However, the three different Bregs subsets showed no significant correlation with expanded disability status scale (EDSS) or annualized relapse rate (ARR). Our findings suggest that the subsets of Bregs may play complex roles in the pathogenesis of NMOSDs and are not correlated with clinical disease severity. Further insights into the potential role of subsets of Bregs could increase our basic knowledge of NMOSDs pathogenesis.

  9. CD38 is a signaling molecule in B-cell chronic lymphocytic leukemia cells.

    Science.gov (United States)

    Deaglio, Silvia; Capobianco, Andrea; Bergui, Luciana; Dürig, Jan; Morabito, Fortunato; Dührsen, Ulrich; Malavasi, Fabio

    2003-09-15

    The prognosis for patients with B-cell chronic lymphocytic leukemia (B-CLL) is generally less favorable for those expressing CD38. Our working hypothesis is that CD38 is not merely a marker in B-CLL, but that it plays a receptor role with pathogenetic potential ruling the proliferation of the malignant clone. CD38 levels were generally low in the patients examined and monoclonal antibody (mAb) ligation was inefficient in signaling. Other cellular models indicated that molecular density and surface organization are critical for CD38 functionality. Interleukin 2 (IL-2) induced a marked up-modulation and surface rearrangement of CD38 in all the patients studied. On reaching a specific expression threshold, CD38 becomes an efficient receptor in purified B-CLL cells. Indeed, mAb ligation is followed by Ca2+ fluxes and by a markedly increased proliferation. The unsuitability of CD38 to perform as a receptor is obviated through close interaction with the B-cell-receptor (BCR) complex and CD19. On mAb binding, CD38 translocates to the membrane lipid microdomains, as shown by a colocalization with the GM1 ganglioside and with CD81, a raft-resident protein. Finally, CD38 signaling in IL-2-treated B-CLL cells prolonged survival and induced the appearance of plasmablasts, providing a pathogenetic hypothesis for the occurrence of Richter syndrome.

  10. Critical role for thymic CD19+CD5+CD1dhiIL-10+ regulatory B cells in immune homeostasis.

    Science.gov (United States)

    Xing, Chen; Ma, Ning; Xiao, He; Wang, Xiaoqian; Zheng, Mingke; Han, Gencheng; Chen, Guojiang; Hou, Chunmei; Shen, Beifen; Li, Yan; Wang, Renxi

    2015-03-01

    This study tested the hypothesis that besides the spleen, LNs, peripheral blood, and thymus contain a regulatory IL-10-producing CD19(+)CD5(+)CD1d(high) B cell subset that may play a critical role in the maintenance of immune homeostasis. Indeed, this population was identified in the murine thymus, and furthermore, when cocultured with CD4(+) T cells, this population of B cells supported the maintenance of CD4(+)Foxp3(+) Tregs in vitro, in part, via the CD5-CD72 interaction. Mice homozygous for Cd19(Cre) (CD19(-/-)) express B cells with impaired signaling and humoral responses. Strikingly, CD19(-/-) mice produce fewer CD4(+)Foxp3(+) Tregs and a greater percentage of CD4(+)CD8(-) and CD4(-)CD8(+) T cells. Consistent with these results, transfer of thymic CD19(+)CD5(+)CD1d(hi) B cells into CD19(-/-) mice resulted in significantly up-regulated numbers of CD4(+)Foxp3(+) Tregs with a concomitant reduction in CD4(+)CD8(-) and CD4(-)CD8(+) T cell populations in the thymus, spleen, and LNs but not in the BM of recipient mice. In addition, thymic CD19(+)CD5(+)CD1d(hi) B cells significantly suppressed autoimmune responses in lupus-like mice via up-regulation of CD4(+)Foxp3(+) Tregs and IL-10-producing Bregs. This study suggests that thymic CD19(+)CD5(+)CD1d(hi)IL-10(+) Bregs play a critical role in the maintenance of immune homeostasis. © Society for Leukocyte Biology.

  11. Characterization and expression analysis of B Cell receptor accessory molecule CD79 gene in humphead snapper ( Lutjanus sanguineus)

    Science.gov (United States)

    Huang, Yucong; Yan, Xiuying; Cai, Shuanghu; Cai, Jia; Jian, Jichang; Lu, Yishan; Tang, Jufen; Wu, Zaohe

    2016-04-01

    CD79, a key component of the B cell antigen receptor complex, is composed of CD79α(Igα) and CD79β(Igβ) encoded by mb-1 and B29 respectively, and plays an important role in B cell signaling. In this study, we isolated and characterized mb-1 and B29 from humphead snapper ( Lutjanus sanguineus). Their tissue distribution and expression profiles after stimulations in vitro and in vivo were also investigated. The humphead snapper mb-1 and B29 contain open reading frames of 684 bp and 606 bp, encoding 227 amino acids and 201 amino acids, respectively. Both CD79α and CD79β possess signal peptide, extracellular Ig domain, transmembrane region and immunoreceptor tyrosine kinase activation motif (ITAM). Mb-1 is highly expressed in lymphoid organs (thymus, posterior kidney and spleen) and mucosal-associated lymphoid tissues (gill and intestine), while B29 is mainly detected in posterior kidney, spleen, gill and skin. Furthermore, transcription of mb-1 and B29 in head kidney leucocytes was up-regulated following lipopolysaccharide (LPS), pokeweed mitogen (PWM), and polyinosinic-polycytidylic acid (PolyI:C) stimulation, respectively, and their expression level in anterior kidney and spleen was also increased after challenged with formalin-inactived Vibrio harveyi. These results indicated that humphead snapper CD79 molecule might play an important role in immune response to pathogen infection.

  12. Chronic lymphocytic leukemia cells acquire regulatory B-cell properties in response to TLR9 and CD40 activation.

    Science.gov (United States)

    Ringelstein-Harlev, Shimrit; Avivi, Irit; Fanadka, Mona; Horowitz, Netanel A; Katz, Tami

    2018-02-15

    Circulating chronic lymphocytic leukemia (CLL) cells share phenotypic features with certain subsets of regulatory B-cells (Bregs). The latter cells have been reported to negatively regulate immune cell responses, mostly by provision of IL-10. The purpose of the current study was to identify and delineate Breg properties of CLL cells. B-cells and T-cells were obtained from the peripheral blood of untreated CLL patients diagnosed according to the 2008 Guidelines of the International Workshop on Chronic Lymphocytic Leukemia. Co-culture assays were used to examine the ability of CLL cells to suppress autologous T-cell immune responses. IL-10 potency of CLL cells was assessed following stimulation with activators of the toll-like receptor 9 (TLR9) or CD40 and was correlated with the inhibitory activity of the cells. TLR9-activated CLL cells were found to increase the frequency of CD4 + CD25 hi FOXp3 + regulatory T-cells (Tregs) and to inhibit autologous CD4 + T-cell proliferation. This signaling cascade proved to control IL-10 generation in CLL cells, which in turn promoted the inhibition of T-cell proliferation by CLL cells. However, CD40 activation of CLL cells, while exhibiting a similar ability to augment Treg frequency, did not either affect IL-10 generation or T-cell proliferation. In conclusion, CLL cells demonstrate a unique clonal quality of adopting Breg properties which promote modulation of T-cell characteristics. TLR9 appears to be a potent activator of regulatory abilities in CLL cells, possibly contributing to preferential immune escape of TLR9-responsive cells.

  13. Circulating regulatory Tfh cells are enriched in patients with chronic hepatitis B infection and induce the differentiation of regulatory B cells.

    Science.gov (United States)

    Wang, Rongxin; Xie, Ruiling; Song, Zongchang

    2018-04-15

    Chronic hepatitis B virus (HBV) infection is a complex disease with dysregulations in the immune system. Follicular helper T (Tfh) cells are professional B helper cells that are crucial to the development of antibody responses and are involved in a variety of diseases. In this study, we examined the circulating Tfh cells in patients with chronic HBV infection. We observed that CD3 + CD4 + CXCR5 + circulating Tfh cells contained a CD25 + Foxp3 + Treg-like subset that was significantly enriched in patients with chronic HBV infections. The CD25 + Tfh subset presented distinctive cytokine secretion profile, such as lower interferon (IFN)-γ and interleukin (IL)-17, and higher transforming growth factor (TGF)-β secretion, compared to the CD25 - Tfh subset. When incubated with autologous naive CD10 - CD27 - CD19 + B cells, the CD25 + Tfh subset was less capable of mediating CD20 -/lo CD38 + plasmablast differentiation than the CD25 - Tfh subset. In terms of Ig production, CD25 + Tfh cells were more potent at inducing IgM but less potent at inducing IgG and IgA than CD25 - Tfh cells. Interestingly, B cells following incubation with CD25 + Tfh cells presented elevated regulatory function, with higher production of IL-10 and enhanced capacity of suppressing autologous CD8 + T cell inflammation. In the chronic HBV-infected patients, the frequency of IL-10 + B cells and the HBV viral load were positively correlated with the frequency of CD25 + Foxp3 + CD4 + CXCR5 + Tfh cells. Together, this study presented that CD25 + Foxp3 + Treg-like Tfh cells were enriched in chronic HBV-infected patients and could promote regulatory B cell functions. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. CD24(hi)CD27⁺ and plasmablast-like regulatory B cells in human chronic graft-versus-host disease.

    Science.gov (United States)

    de Masson, Adèle; Bouaziz, Jean-David; Le Buanec, Hélène; Robin, Marie; O'Meara, Alix; Parquet, Nathalie; Rybojad, Michel; Hau, Estelle; Monfort, Jean-Benoît; Branchtein, Mylène; Michonneau, David; Dessirier, Valérie; Sicre de Fontbrune, Flore; Bergeron, Anne; Itzykson, Raphaël; Dhédin, Nathalie; Bengoufa, Djaouida; Peffault de Latour, Régis; Xhaard, Aliénor; Bagot, Martine; Bensussan, Armand; Socié, Gérard

    2015-03-12

    Interleukin 10 (IL-10)-producing B cells (regulatory B cells [Bregs]) regulate autoimmunity in mice and humans, and a regulatory role of IL-10-producing plasma cells has been described in mice. Dysfunction of B cells that maintain homeostasis may play a role in the pathogenesis of chronic graft-versus-host disease (cGVHD) after allogeneic stem cell transplantation. Here, we found a relation between decreased Breg frequencies and cGVHD severity. An impaired ability of B cells to produce IL-10, possibly linked to poor signal transducer and activator of transcription 3 and extracellular signal-regulated kinase phosphorylation, was found in patients with active cGVHD. IL-10 production was not confined to a single B-cell subset, but enriched in both the CD24(hi)CD27(+) and CD27(hi)CD38(hi) plasmablast B-cell compartments. In vitro plasmablast differentiation increased the frequency of IL-10-producing B cells. We confirmed that allogeneic transplant recipients had an impaired reconstitution of the memory B-cell pool. cGVHD patients had less CD24(hi)CD27(+) B cells and IL-10-producing CD24(hi)CD27(+) B cells. Patients with cGVHD had increased plasmablast frequencies but decreased IL-10-producing plasmablasts. These results suggest a role of CD24(hi)CD27(+) B-cell and plasmablast-derived IL-10 in the regulation of human cGVHD. © 2015 by The American Society of Hematology.

  15. [Regulatory B cells activated by CpG-ODN combined with anti-CD40 monoclonal antibody inhibit CD4(+)T cell proliferation].

    Science.gov (United States)

    Wang, Keng; Tao, Lei; Su, Jianbing; Zhang, Yueyang; Zou, Binhua; Wang, Yiyuan; Li, Xiaojuan

    2016-09-01

    Objective To observe the immunosuppressive function of regulatory B cells (Bregs) in vitro after activated by CpG oligodeoxynucleotide (CpG-ODN) and anti-CD40 mAb. Methods Mice splenic CD5(+)CD1d(high)B cells and CD5(-)CD1d(low)B cells were sorted by flow cytometry. These B cells were first stimulated with CpG-ODN combined with anti-CD40 mAb for 24 hours, and then co-cultured with purified CD4(+)T cells. The interleukin 10 (IL-10) expression in the activated Bregs and other B cell subset, as well as the proliferation and interferon γ (IFN-γ) expression in the CD4(+) T cells activated by anti-CD3 mAb plus anti-CD28 mAb were determined by flow cytometry. Results CD5(+)CD1d(high) B cells activated by CpG-ODN plus anti-CD40 mAb blocked the up-regulated CD4(+)T proliferation and significantly reduced the IFN-γ level. At the same time, activated CD5(-)CD1d(low)B cells showed no inhibitory effect on CD4(+)T cells. Further study revealed that IL-10 expression in the CD5(+)CD1d(high) B cells were much higher than that in the CD5(-)CD1d(low)B cells after stimulated with CpG-ODN combined with anti-CD40 mAb for 24 hours. Conclusion CD5(+)CD1d(high) B cells activated by CpG-ODN combined with anti-CD40 mAb have immune inhibitory effects on CD4(+)T cell activation in vitro , which possibly due to IL-10 secretion.

  16. Identification of a new gene regulatory circuit involving B cell receptor activated signaling using a combined analysis of experimental, clinical and global gene expression data

    Science.gov (United States)

    Schrader, Alexandra; Meyer, Katharina; Walther, Neele; Stolz, Ailine; Feist, Maren; Hand, Elisabeth; von Bonin, Frederike; Evers, Maurits; Kohler, Christian; Shirneshan, Katayoon; Vockerodt, Martina; Klapper, Wolfram; Szczepanowski, Monika; Murray, Paul G.; Bastians, Holger; Trümper, Lorenz; Spang, Rainer; Kube, Dieter

    2016-01-01

    To discover new regulatory pathways in B lymphoma cells, we performed a combined analysis of experimental, clinical and global gene expression data. We identified a specific cluster of genes that was coherently expressed in primary lymphoma samples and suppressed by activation of the B cell receptor (BCR) through αIgM treatment of lymphoma cells in vitro. This gene cluster, which we called BCR.1, includes numerous cell cycle regulators. A reduced expression of BCR.1 genes after BCR activation was observed in different cell lines and also in CD10+ germinal center B cells. We found that BCR activation led to a delayed entry to and progression of mitosis and defects in metaphase. Cytogenetic changes were detected upon long-term αIgM treatment. Furthermore, an inverse correlation of BCR.1 genes with c-Myc co-regulated genes in distinct groups of lymphoma patients was observed. Finally, we showed that the BCR.1 index discriminates activated B cell-like and germinal centre B cell-like diffuse large B cell lymphoma supporting the functional relevance of this new regulatory circuit and the power of guided clustering for biomarker discovery. PMID:27166259

  17. Quantitation of multiple myeloma oncogene 1/interferon-regulatory factor 4 gene expression in malignant B-cell proliferations and normal leukocytes.

    Science.gov (United States)

    Yamada, M; Asanuma, K; Kobayashi, D; Moriai, R; Yajima, T; Yagihashi, A; Yamamori, S; Watanabe, N

    2001-01-01

    We studied multiple myeloma oncogene 1/interferon-regulatory factor 4 (MUM1/IRF4) mRNA expression in various malignant human hematopoietic cell lines and normal leukocyte fractions. A quantitative reverse transcription-polymerase chain reaction was used to assess expression and chromosomes were examined for anomalies by fluorescent in situ hybridization. Among 12 cell lines examined, mRNA transcripts were expressed only in B-lymphoblastic and myeloma cell lines. Myeloma cells and malignant cell lines derived from mature B cells expressed more transcript than cell lines derived from immature B cells. Transcript levels, however, showed no association with chromosomal translocations. Expression in B-cell fractions from healthy donors was much less than in the malignant cells. In addition, MUM1/IRF4 mRNA expressed in samples from patients with acute lymphoblastic leukemia derived from B cells but not T cells. Our results suggested that MUM1/IRF4 gene expression is related to stage of differentiation of malignant B cells and they indicated the possibility that the quantitative analysis of MUM1/IRF4 gene is a useful tool for detection of malignant B-cell proliferations in clinical laboratory tests.

  18. TLR5 signaling enhances the proliferation of human allogeneic CD40-activated B cell induced CD4hiCD25+ regulatory T cells.

    Directory of Open Access Journals (Sweden)

    Ping-Lung Chan

    Full Text Available Although diverse functions of different toll-like receptors (TLR on human natural regulatory T cells have been demonstrated recently, the role of TLR-related signals on human induced regulatory T cells remain elusive. Previously our group developed an ex vivo high-efficient system in generating human alloantigen-specific CD4(hiCD25(+ regulatory T cells from naïve CD4(+CD25(- T cells using allogeneic CD40-activated B cells as stimulators. In this study, we investigated the role of TLR5-related signals on the generation and function of these novel CD4(hiCD25(+ regulatory T cells. It was found that induced CD4(hiCD25(+ regulatory T cells expressed an up-regulated level of TLR5 compared to their precursors. The blockade of TLR5 using anti-TLR5 antibodies during the co-culture decreased CD4(hiCD25(+ regulatory T cells proliferation by induction of S phase arrest. The S phase arrest was associated with reduced ERK1/2 phosphorylation. However, TLR5 blockade did not decrease the CTLA-4, GITR and FOXP3 expressions, and the suppressive function of CD4(hiCD25(+ regulatory T cells. In conclusion, we discovered a novel function of TLR5-related signaling in enhancing the proliferation of CD4(hiCD25(+ regulatory T cells by promoting S phase progress but not involved in the suppressive function of human CD40-activated B cell-induced CD4(hiCD25(+ regulatory T cells, suggesting a novel role of TLR5-related signals in the generation of induced regulatory T cells.

  19. CD54/intercellular adhesion molecule 1 and major histocompatibility complex II signaling induces B cells to express interleukin 2 receptors and complements help provided through CD40 ligation

    DEFF Research Database (Denmark)

    Poudrier, J; Owens, T

    1994-01-01

    We have examined signaling roles for CD54 intercellular adhesion molecule 1 and major histocompatibility complex (MHC) II as contact ligands during T help for B cell activation. We used a T helper 1 (Th1)-dependent helper system that was previously shown to be contact as well as interleukin 2 (IL-2......) dependent to demonstrate the relative roles of CD54, MHC II, and CD40 signaling in the events leading to the induction of B cell proliferation and responsiveness to IL-2. Paraformaldehyde-fixed activated Th1-induced expression of IL-2R alpha, IL-2R beta, and B7, and upregulated MHC II and CD54 on B cells...... resulted in the upregulated expression of MHC II and of CD54 and B7, respectively, analogous to the effect of fixed activated Th1 cells. B7 expression was further enhanced by co-cross-linking CD54 and MHC II. Cross-linking of CD40 achieved comparable effects. Strikingly, cross-linking ligation of CD54...

  20. Reduced CD5(+) CD24(hi) CD38(hi) and interleukin-10(+) regulatory B cells in active anti-neutrophil cytoplasmic autoantibody-associated vasculitis permit increased circulating autoantibodies.

    Science.gov (United States)

    Aybar, L T; McGregor, J G; Hogan, S L; Hu, Y; Mendoza, C E; Brant, E J; Poulton, C J; Henderson, C D; Falk, R J; Bunch, D O

    2015-05-01

    Pathogenesis of anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis is B cell-dependent, although how particular B cell subsets modulate immunopathogenesis remains unknown. Although their phenotype remains controversial, regulatory B cells (Bregs ), play a role in immunological tolerance via interleukin (IL)-10. Putative CD19(+) CD24(hi) CD38(hi) and CD19(+) CD24(hi) CD27(+) Bregs were evaluated in addition to their CD5(+) subsets in 69 patients with ANCA-associated vasculitis (AAV). B cell IL-10 was verified by flow cytometry following culture with CD40 ligand and cytosine-phosphate-guanosine (CpG) DNA. Patients with active disease had decreased levels of CD5(+) CD24(hi) CD38(hi) B cells and IL-10(+) B cells compared to patients in remission and healthy controls (HCs). As IL-10(+) and CD5(+) CD24(hi) CD38(hi) B cells normalized in remission within an individual, ANCA titres decreased. The CD5(+) subset of CD24(hi) CD38(hi) B cells decreases in active disease and rebounds during remission similarly to IL-10-producing B cells. Moreover, CD5(+) B cells are enriched in the ability to produce IL-10 compared to CD5(neg) B cells. Together these results suggest that CD5 may identify functional IL-10-producing Bregs . The malfunction of Bregs during active disease due to reduced IL-10 expression may thus permit ANCA production. © 2014 British Society for Immunology.

  1. Similar disturbances in B cell activity and regulatory T cell function in Henoch-Schonlein purpura and systemic lupus erythematosus

    International Nuclear Information System (INIS)

    Beale, M.G.; Nash, G.S.; Bertovich, M.J.; MacDermott, R.P.

    1982-01-01

    The immunoglobulin synthesizing activities of peripheral mononuclear cells (MNC) from five patients with Henoch-Schonlein purpura (HSP) and eight patients with active systemic lupus erythematosus (SLE) were compared. Cumulative amounts of IgM, IgG, and IgA synthesized and secreted by unstimulated and PWM-stimulated patient cells over a 12-day period were determied in a solid-phase radioimmunoassay. In unstimulated control cultures mean rates of IgM, IgG, and IgA synthesis were less than 250 ng/ml. The synthetic activities of patient MNC were markedly increased. In HSP cultures IgA was the major immunoglobulin class produced (2810 x/divide 1.33 ng/ml) followed by IgG (1754 x/divide 1.32 ng/ml) and IgM (404 x/divide 1.16 ng/ml). In SLE cultures IgA and IgG syntheses were equally elevated (4427 x/divide 1.20 and 4438 x/divide 1.49 ng/ml, respectively) whereas IgM synthesis averaged 967 x/divide 1.66 ng/ml. PWM stimulation of pateient MNC caused a sharp decline in the synthesis of all three immunoglobulin classes. After T cell depletion B cell-enriched fractions from HSP and SLE patients maintained high levels of IgA and IgG synthesis that were inhibited by PWM and by normal allogeneic but not autologous T cells. In PWM-stimulted co-cultures, patient T cells nonspecifically suppressed the synthetic activities of autologous and control B cells. in contrast patient B cells achieved normal levels of immunoglobulin synthesis when cultured with control T cells plus PWM. In longitudinal studies patient B and T cell disturbances persisted despite clinical improvement

  2. An in silico approach reveals associations between genetic and epigenetic factors within regulatory elements in B cells from primary Sjögren’s syndrome patients

    Directory of Open Access Journals (Sweden)

    Orsia D. Konsta

    2015-08-01

    Full Text Available Recent advances in genetics have highlighted several regions and candidate genes associated with primary Sjögren's syndrome (SS, a systemic autoimmune epithelitis that combines exocrine gland dysfunctions, and focal lymphocytic infiltrations. In addition to genetic factors, it is now clear that epigenetic deregulations are present during SS and restricted to specific cell type subsets such as lymphocytes and salivary gland epithelial cells. In this study, 72 single nucleotide polymorphisms (SNPs associated with 43 SS gene risk factors were selected from publicly available and peer reviewed literature for further in silico analysis. SS risk variant location was tested revealing a broad distribution in coding sequences (5.6%, intronic sequences (55.6%, upstream/downstream genic regions (30.5%, and intergenic regions (8.3%. Moreover, a significant enrichment of regulatory motifs (promoter, enhancer, insulator, DNAse peak and eQTL characterizes SS risk variants (94.4%. Next, screening SNPs in high linkage disequilibrium (r2 ≥ 0.8 in Caucasians revealed 645 new variants including 5 SNPs with missense mutations, and indicated an enrichment of transcriptionally active motifs according to the cell type (B cells > monocytes > T cells >> A549. Finally, we looked at SS risk variants for histone markers in B cells (GM12878, monocytes (CD14+ and epithelial cells (A548. Active histone markers were associated with SS risk variants at both promoters and enhancers in B cells, and within enhancers in monocytes. In conclusion and based on the obtained in silico results, that need further confirmation, associations were observed between SS genetic risk factors and epigenetic factors and these associations predominate in B cells such as those observed at the FAM167A-BLK locus.

  3. Protective Effects of Total Glucosides of Paeony on N-nitrosodiethylamine-induced Hepatocellular Carcinoma in Rats via Down-regulation of Regulatory B Cells.

    Science.gov (United States)

    Song, S S; Yuan, P F; Li, P P; Wu, H X; Ni, W J; Lu, J T; Wei, W

    2015-01-01

    Total glucoside of paeony (TGP), extracted from the root of Paeonia Lactiflora, has been known to show anti-inflammatory, anti-oxidative, hepato-protective and immuno-regulatory activities. The aim of this present study was to determine the anti-tumor effect of TGP against N-nitrosodiethylamine (DEN)-induced hepatocellular carcinoma (HCC) in rats, and to find the related mechanisms. Rat HCC model was established by intragastrically administrating with DEN (8 mg/kg). We found the number of tumor nodules and the index of liver and spleen were increased in the model group compared with the normal group, and was significantly decreased by TGP. Additionally, TGP obviously improved the hepatic pathological lesions induced by DEN, and decreased the elevated levels of serum alanine aminotransferase (ALT), glutamic oxalacetic transaminase (AST), alkaline phosphatase (ALP) and alpha fetoprotein (AFP) by DEN. Moreover, TGP decreased the level of B cell-activating factor (BAFF) and the proportion of IL-10-producing regulatory B cells (Bregs), and the decrease of BAFF by TGP is positively correlated to the decrease of IL-10-producing Bregs by TGP. These results suggest that TGP had a good therapeutic action on DEN-induced HCC rats, which might be due to its down-regulation of Bregs through reducing the level of BAFF.

  4. B-cell-mediated strategies to fight chronic allograft rejection

    Directory of Open Access Journals (Sweden)

    Ali H Dalloul

    2013-12-01

    Full Text Available Solid organs have been transplanted for decades. Since the improvement in graft selection and in medical and surgical procedures, the likelihood of graft function after one year is now close to 90%. Nonetheless even well-matched recipients continue to need medications for the rest of their lives hence adverse side effects and enhanced morbidity. Understanding Immune rejection mechanisms, is of increasing importance since the greater use of living-unrelated donors and genetically unmatched individuals. Chronic rejection is devoted to T-cells, however the role of B-cells in rejection has been appreciated recently by the observation that B-cell depletion improve graft survival. By contrast however, B-cells can be beneficial to the grafted tissue. This protective effect is secondary to either the secretion of protective antibodies or the induction of B-cells that restrain excessive inflammatory responses, chiefly by local provision of IL-10, or inhibit effector T-cells by direct cellular interactions. As a proof of concept B-cell-mediated infectious transplantation tolerance could be achieved in animal models, and evidence emerged that the presence of such B-cells in transplanted patients correlate with a favorable outcome. Among these populations, regulatory B-cells constitute a recently described population. These cells may develop as a feedback mechanism to prevent uncontrolled reactivity to antigens and inflammatory stimuli. The difficult task for the clinician, is to quantify the respective ratios and functions of tolerant vs effector B-cells within a transplanted organ, at a given time point in order to modulate B-cell-directed therapy. Several receptors at the B-cell membrane as well as signaling molecules, can now be targeted for this purpose. Understanding the temporal expansion of regulatory B-cells in grafted patients and the stimuli that activate them will help in the future to implement specific strategies aimed at fighting chronic

  5. Exacerbation of spontaneous autoimmune nephritis following regulatory T cell depletion in B cell lymphoma 2-interacting mediator knock-out mice.

    Science.gov (United States)

    Wang, Y M; Zhang, G Y; Wang, Y; Hu, M; Zhou, J J; Sawyer, A; Cao, Q; Wang, Y; Zheng, G; Lee, V W S; Harris, D C H; Alexander, S I

    2017-05-01

    Regulatory T cells (T regs ) have been recognized as central mediators for maintaining peripheral tolerance and limiting autoimmune diseases. The loss of T regs or their function has been associated with exacerbation of autoimmune disease. However, the temporary loss of T regs in the chronic spontaneous disease model has not been investigated. In this study, we evaluated the role of T regs in a novel chronic spontaneous glomerulonephritis model of B cell lymphoma 2-interacting mediator (Bim) knock-out mice by transient depleting T regs . Bim is a pro-apoptotic member of the B cell lymphoma 2 (Bcl-2) family. Bim knock-out (Bim -/- ) mice fail to delete autoreactive T cells in thymus, leading to chronic spontaneous autoimmune kidney disease. We found that T reg depletion in Bim -/- mice exacerbated the kidney injury with increased proteinuria, impaired kidney function, weight loss and greater histological injury compared with wild-type mice. There was a significant increase in interstitial infiltrate of inflammatory cells, antibody deposition and tubular damage. Furthermore, the serum levels of cytokines interleukin (IL)-2, IL-4, IL-6, IL-10, IL-17α, interferon (IFN)-γ and tumour necrosis factor (TNF)-α were increased significantly after T reg depletion in Bim -/- mice. This study demonstrates that transient depletion of T regs leads to enhanced self-reactive T effector cell function followed by exacerbation of kidney disease in the chronic spontaneous kidney disease model of Bim-deficient mice. © 2017 British Society for Immunology.

  6. Ligation of TLR7 on CD19(+) CD1d(hi) B cells suppresses allergic lung inflammation via regulatory T cells.

    Science.gov (United States)

    Khan, Adnan R; Amu, Sylvie; Saunders, Sean P; Hams, Emily; Blackshields, Gordon; Leonard, Martin O; Weaver, Casey T; Sparwasser, Tim; Sheils, Orla; Fallon, Padraic G

    2015-06-01

    B cells have been described as having the capacity to regulate cellular immune responses and suppress inflammatory processes. One such regulatory B-cell population is defined as IL-10-producing CD19(+) CD1d(hi) cells. Previous work has identified an expansion of these cells in mice infected with the helminth, Schistosoma mansoni. Here, microarray analysis of CD19(+) CD1d(hi) B cells from mice infected with S. mansoni demonstrated significantly increased Tlr7 expression, while CD19(+) CD1d(hi) B cells from uninfected mice also demonstrated elevated Tlr7 expression. Using IL-10 reporter, Il10(-/-) and Tlr7(-/-) mice, we formally demonstrate that TLR7 ligation of CD19(+) CD1d(hi) B cells increases their capacity to produce IL-10. In a mouse model of allergic lung inflammation, the adoptive transfer of TLR7-elicited CD19(+) CD1d(hi) B cells reduced airway inflammation and associated airway hyperresponsiveness. Using DEREG mice to deplete FoxP3(+) T regulatory cells in allergen-sensitized mice, we show that that TLR7-elicited CD19(+) CD1d(hi) B cells suppress airway hyperresponsiveness via a T regulatory cell dependent mechanism. These studies identify that TLR7 stimulation leads to the expansion of IL-10-producing CD19(+) CD1d(hi) B cells, which can suppress allergic lung inflammation via T regulatory cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Regulatory T-cells in B-cell chronic lymphocytic leukemia: their role in disease progression and autoimmune cytopenias.

    Science.gov (United States)

    Lad, Deepesh P; Varma, Subhash; Varma, Neelam; Sachdeva, Man Updesh Singh; Bose, Parveen; Malhotra, Pankaj

    2013-05-01

    Regulatory T-cells (Tregs) have been shown to be important for the balance of autoimmunity and oncogenesis. Tregs have a protective role in autoimmune diseases and conversely promote oncogenesis. Chronic lymphocytic leukemia (CLL) is unique in being at the cross-roads of oncogenesis and autoimmunity. We studied Tregs, defined as CD4+CD25(high)CD127(low)FOXP3+, in 32 treatment-naive patients with CLL. Our study shows that patients with CLL had a higher absolute Treg count than the control group (p < 0.001). A progressive increase of Tregs was noted in advanced stages of the disease (p < 0.001). The increase in absolute Treg count is more significant than the increase in percentage Tregs. The absolute Treg count appears to be more important in disease pathogenesis. The absolute Treg count was significantly higher in those patients having autoimmune cytopenias. There was an inverse correlation between lymphocyte doubling time and absolute Treg count (p = 0.03). The absolute Treg count may be used as a prognostic marker in CLL.

  8. Regulatory B cells (CD19(+)CD38(hi)CD24(hi)) in alloimmunized and non-alloimmunized children with β-thalassemia major.

    Science.gov (United States)

    Zahran, Asmaa M; Elsayh, Khalid I; Saad, Khaled; Embaby, Mostafa; Ali, Ahmed M

    2016-03-01

    β-Thalassemia major (BTM) is considered the most common hemoglobinopathy in Egypt and is one of the major health problems in our locality. We investigated the frequency of B-regulatory cells (CD19(+)CD38(hi)CD24(hi)); (Bregs) among polytransfused alloimmunized and non-alloimmunized children with BTM. The study included 110 polytransfused pediatric patients with β-thalassemia major. Clinical and transfusion records of all studied patients were reviewed. Indirect antiglobulin test was performed to detect the presence of alloantibodies. We used flow cytometry for detection of CD19(+)CD38(hi)CD24(hi) regulatory B cells. Alloimmunization was detected in 35.5% of thalassemic patients (39/110). The analysis of our data showed a significantly higher frequency of Bregs (CD19(+)CD38(hi)CD24(hi)) in the peripheral blood of both alloimmunized and non-alloimmunized patients as compared to healthy controls. Our data showed that the frequencies of CD19(+)CD24(hi)CD38(hi) Bregs cells were significantly increased in children with BTM. Our data suggested that Bregs cells could play a role in the clinical course of BTM. The relationship of Bregs to immune disorders in BTM children remains to be determined. Further longitudinal study with a larger sample size is warranted to explore the mechanisms of Breg cells in the disease process in BTM patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. B-cell activating factor detected on both naïve and memory B cells in bullous pemphigoid.

    Science.gov (United States)

    Qian, Hua; Kusuhara, Masahiro; Li, Xiaoguang; Tsuruta, Daisuke; Tsuchisaka, Atsunari; Ishii, Norito; Koga, Hiroshi; Hayakawa, Taihei; Ohara, Koji; Karashima, Tadashi; Ohyama, Bungo; Ohata, Chika; Furumura, Minao; Hashimoto, Takashi

    2014-08-01

    B-cell activating factor (BAFF), an important immune regulatory cytokine, is involved in development of autoimmune diseases. Although BAFF is expressed in various cells, including dendritic cells (DCs) and monocytes, BAFF expression on B cells has not been well documented. In the present study, BAFF molecules on DCs and naïve and memory B cells in autoimmune bullous diseases, including pemphigus vulgaris, pemphigus foliaceus and bullous pemphigoid (BP), were analysed by flow cytometry. Compared with healthy controls (HC), BAFF expression on naïve and memory B cells increased significantly in BP. No difference in BAFF receptor expression in naïve and memory B cells was shown among all study groups. Furthermore, BAFF expression in both naïve and memory B cells of BP, but not HC, was detected by confocal microscopic analysis. These results implied that BAFF expressed by B cells may play a pathogenic role in autoimmune bullous diseases, particularly BP. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Antidiabetic effects of glucokinase regulatory protein small-molecule disruptors

    Science.gov (United States)

    Lloyd, David J.; St Jean, David J.; Kurzeja, Robert J. M.; Wahl, Robert C.; Michelsen, Klaus; Cupples, Rod; Chen, Michelle; Wu, John; Sivits, Glenn; Helmering, Joan; Komorowski, Renée; Ashton, Kate S.; Pennington, Lewis D.; Fotsch, Christopher; Vazir, Mukta; Chen, Kui; Chmait, Samer; Zhang, Jiandong; Liu, Longbin; Norman, Mark H.; Andrews, Kristin L.; Bartberger, Michael D.; van, Gwyneth; Galbreath, Elizabeth J.; Vonderfecht, Steven L.; Wang, Minghan; Jordan, Steven R.; Véniant, Murielle M.; Hale, Clarence

    2013-12-01

    Glucose homeostasis is a vital and complex process, and its disruption can cause hyperglycaemia and type II diabetes mellitus. Glucokinase (GK), a key enzyme that regulates glucose homeostasis, converts glucose to glucose-6-phosphate in pancreatic β-cells, liver hepatocytes, specific hypothalamic neurons, and gut enterocytes. In hepatocytes, GK regulates glucose uptake and glycogen synthesis, suppresses glucose production, and is subject to the endogenous inhibitor GK regulatory protein (GKRP). During fasting, GKRP binds, inactivates and sequesters GK in the nucleus, which removes GK from the gluconeogenic process and prevents a futile cycle of glucose phosphorylation. Compounds that directly hyperactivate GK (GK activators) lower blood glucose levels and are being evaluated clinically as potential therapeutics for the treatment of type II diabetes mellitus. However, initial reports indicate that an increased risk of hypoglycaemia is associated with some GK activators. To mitigate the risk of hypoglycaemia, we sought to increase GK activity by blocking GKRP. Here we describe the identification of two potent small-molecule GK-GKRP disruptors (AMG-1694 and AMG-3969) that normalized blood glucose levels in several rodent models of diabetes. These compounds potently reversed the inhibitory effect of GKRP on GK activity and promoted GK translocation both in vitro (isolated hepatocytes) and in vivo (liver). A co-crystal structure of full-length human GKRP in complex with AMG-1694 revealed a previously unknown binding pocket in GKRP distinct from that of the phosphofructose-binding site. Furthermore, with AMG-1694 and AMG-3969 (but not GK activators), blood glucose lowering was restricted to diabetic and not normoglycaemic animals. These findings exploit a new cellular mechanism for lowering blood glucose levels with reduced potential for hypoglycaemic risk in patients with type II diabetes mellitus.

  11. A systems biology approach identified different regulatory networks targeted by KSHV miR-K12-11 in B cells and endothelial cells.

    Science.gov (United States)

    Yang, Yajie; Boss, Isaac W; McIntyre, Lauren M; Renne, Rolf

    2014-08-08

    Kaposi's sarcoma associated herpes virus (KSHV) is associated with tumors of endothelial and lymphoid origin. During latent infection, KSHV expresses miR-K12-11, an ortholog of the human tumor gene hsa-miR-155. Both gene products are microRNAs (miRNAs), which are important post-transcriptional regulators that contribute to tissue specific gene expression. Advances in target identification technologies and molecular interaction databases have allowed a systems biology approach to unravel the gene regulatory networks (GRNs) triggered by miR-K12-11 in endothelial and lymphoid cells. Understanding the tissue specific function of miR-K12-11 will help to elucidate underlying mechanisms of KSHV pathogenesis. Ectopic expression of miR-K12-11 differentially affected gene expression in BJAB cells of lymphoid origin and TIVE cells of endothelial origin. Direct miRNA targeting accounted for a small fraction of the observed transcriptome changes: only 29 genes were identified as putative direct targets of miR-K12-11 in both cell types. However, a number of commonly affected biological pathways, such as carbohydrate metabolism and interferon response related signaling, were revealed by gene ontology analysis. Integration of transcriptome profiling, bioinformatic algorithms, and databases of protein-protein interactome from the ENCODE project identified different nodes of GRNs utilized by miR-K12-11 in a tissue-specific fashion. These effector genes, including cancer associated transcription factors and signaling proteins, amplified the regulatory potential of a single miRNA, from a small set of putative direct targets to a larger set of genes. This is the first comparative analysis of miRNA-K12-11's effects in endothelial and B cells, from tissues infected with KSHV in vivo. MiR-K12-11 was able to broadly modulate gene expression in both cell types. Using a systems biology approach, we inferred that miR-K12-11 establishes its GRN by both repressing master TFs and influencing

  12. Thymic B cell development is controlled by the B potential of progenitors via both hematopoietic-intrinsic and thymic microenvironment-intrinsic regulatory mechanisms.

    Directory of Open Access Journals (Sweden)

    Shiyun Xiao

    Full Text Available Hematopoietic stem cells (HSCs derived from birth through adult possess differing differentiation potential for T or B cell fate in the thymus; neonatal bone marrow (BM cells also have a higher potential for B cell production in BM compared to adult HSCs. We hypothesized that this hematopoietic-intrinsic B potential might also regulate B cell development in the thymus during ontogeny.Foxn1lacZ mutant mice are a model in which down regulation of a thymic epithelial cell (TEC specific transcription factor beginning one week postnatal causes a dramatic reduction of thymocytes production. In this study, we found that while T cells were decreased, the frequency of thymic B cells was greatly increased in these mutants in the perinatal period. We used this model to characterize the mechanisms in the thymus controlling B cell development.Foxn1lacZ mutants, T cell committed intrathymic progenitors (DN1a,b were progressively reduced beginning one week after birth, while thymic B cells peaked at 3-4 weeks with pre-B-II progenitor phenotype, and originated in the thymus. Heterochronic chimeras showed that the capacity for thymic B cell production was due to a combination of higher B potential of neonatal HSCs, combined with a thymic microenvironment deficiency including reduction of DL4 and increase of IL-7 that promoted B cell fate.Our findings indicate that the capacity and time course for thymic B-cell production are primarily controlled by the hematopoietic-intrinsic potential for B cells themselves during ontogeny, but that signals from TECs microenvironment also influence the frequency and differentiation potential of B cell development in the thymus.

  13. B cell receptor accessory molecule CD79α: characterisation and expression analysis in a cartilaginous fish, the spiny dogfish (Squalus acanthias).

    Science.gov (United States)

    Li, Ronggai; Wang, Tiehui; Bird, Steve; Zou, Jun; Dooley, Helen; Secombes, Christopher J

    2013-06-01

    CD79α (also known as Igα) is a component of the B cell antigen receptor complex and plays an important role in B cell signalling. The CD79α protein is present on the surface of B cells throughout their life cycle, and is absent on all other healthy cells, making it a highly reliable marker for B cells in mammals. In this study the spiny dogfish (Squalus acanthias) CD79α (SaCD79α) is described and its expression studied under constitutive and stimulated conditions. The spiny dogfish CD79α cDNA contains an open reading frame of 618 bp, encoding a protein of 205 amino acids. Comparison of the SaCD79α gene with that of other species shows that the gross structure (number of exons, exon/intron boundaries, etc.) is highly conserved across phylogeny. Additionally, analysis of the 5' flanking region shows SaCD79α lacks a TATA box and possesses binding sites for multiple transcription factors implicated in its B cell-specific gene transcription in other species. Spiny dogfish CD79α is most highly expressed in immune tissues, such as spleen, epigonal and Leydig organ, and its transcript level significantly correlates with those of spiny dogfish immunoglobulin heavy chains. Additionally, CD79α transcription is up-regulated, to a small but significant degree, in peripheral blood cells following stimulation with pokeweed mitogen. These results strongly indicate that, as in mammals, spiny dogfish CD79α is expressed by shark B cells where it associates with surface-bound immunoglobulin to form a fully functional BCR, and thus may serve as a pan-B cell marker in future shark immunological studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Production of recombinant Ig molecules from antigen-selected single B cells and restricted usage of Ig-gene segments by anti-D antibodies

    NARCIS (Netherlands)

    Dohmen, Serge E.; Mulder, Arend; Verhagen, Onno J. H. M.; Eijsink, Chantal; Franke-van Dijk, Marry E. I.; van der Schoot, C. Ellen

    2005-01-01

    The Ig-genes of the heavy chains in anti-D-specific hybridomas and Fab/scFv-fragments selected from phage-display libraries are restricted to a group of closely related genes (IGHV3s genes). We analyzed the Ig-gene repertoire in anti-D-specific B cells of two hyperimmunized donors using a completely

  15. Upregulation of CD19⁺CD24(hi)CD38(hi) regulatory B cells is associated with a reduced risk of acute lung injury in elderly pneumonia patients.

    Science.gov (United States)

    Song, Haihan; Xi, Jianjun; Li, Guang-Gang; Xu, Shumin; Wang, Chunmei; Cheng, Tingting; Li, Hongqiang; Zhang, Ying; Liu, Xiandong; Bai, Jianwen

    2016-04-01

    Acute lung injury (ALI) is a common complication in elderly pneumonia patients who have a rapid progression, and is accompanied by a high mortality rate. Because the treatment options of ALI are limited to supportive care, identifying pneumonia patients who are at higher risk of ALI development is the emphasis of many studies. Here, we approach this problem from an immunological perspective by examining CD19(+)CD24(hi)CD38(hi) B cells, an important participant in acute and chronic inflammation. We find that elderly pneumonia patients have elevated CD19(+)CD24(hi)CD38(hi) B cell frequency compared to healthy individuals. This B cell population may express a higher level of IL-10, which has been was shown to suppress CD4(+) T cell-mediated proinflammatory cytokine interferon gamma (IFNg) and tumor necrosis factor alpha (TNFa) production, through an IL-10-dependent mechanism. We also observe that the frequency of CD19(+)CD24(hi)CD38(hi) B cell is positively correlated with the frequency of CD4(+)CD25(+)Foxp3(+)Tregs in peripheral blood. Moreover, consistent with CD19(+)CD24(hi)CD38(hi) B cell's anti-inflammatory role, we find that pneumonia patients who later developed ALI have reduced level of CD19(+)CD24(hi)CD38(hi) B cells. Together, our results demonstrated that CD19(+)CD24(hi)CD38(hi) B cells in pneumonia patients possess regulatory function in vivo, and are associated with a reduced ALI risk.

  16. HCV Infection and B-Cell Lymphomagenesis

    Directory of Open Access Journals (Sweden)

    Masahiko Ito

    2011-01-01

    Full Text Available Hepatitis C virus (HCV has been recognized as a major cause of chronic liver diseases worldwide. It has been suggested that HCV infects not only hepatocytes but also mononuclear lymphocytes including B cells that express the CD81 molecule, a putative HCV receptor. HCV infection of B cells is the likely cause of B-cell dysregulation disorders such as mixed cryoglobulinemia, rheumatoid factor production, and B-cell lymphoproliferative disorders that may evolve into non-Hodgkin's lymphoma (NHL. Epidemiological data indicate an association between HCV chronic infection and the occurrence of B-cell NHL, suggesting that chronic HCV infection is associated at least in part with B-cell lymphomagenesis. In this paper, we aim to provide an overview of recent literature, including our own, to elucidate a possible role of HCV chronic infection in B-cell lymphomagenesis.

  17. B cell depletion reduces T cell activation in pancreatic islets in a murine autoimmune diabetes model.

    Science.gov (United States)

    Da Rosa, Larissa C; Boldison, Joanne; De Leenheer, Evy; Davies, Joanne; Wen, Li; Wong, F Susan

    2018-06-01

    Type 1 diabetes is a T cell-mediated autoimmune disease characterised by the destruction of beta cells in the islets of Langerhans, resulting in deficient insulin production. B cell depletion therapy has proved successful in preventing diabetes and restoring euglycaemia in animal models of diabetes, as well as in preserving beta cell function in clinical trials in the short term. We aimed to report a full characterisation of B cell kinetics post B cell depletion, with a focus on pancreatic islets. Transgenic NOD mice with a human CD20 transgene expressed on B cells were injected with an anti-CD20 depleting antibody. B cells were analysed using multivariable flow cytometry. There was a 10 week delay in the onset of diabetes when comparing control and experimental groups, although the final difference in the diabetes incidence, following prolonged observation, was not statistically significant (p = 0.07). The co-stimulatory molecules CD80 and CD86 were reduced on stimulation of B cells during B cell depletion and repopulation. IL-10-producing regulatory B cells were not induced in repopulated B cells in the periphery, post anti-CD20 depletion. However, the early depletion of B cells had a marked effect on T cells in the local islet infiltrate. We demonstrated a lack of T cell activation, specifically with reduced CD44 expression and effector function, including IFN-γ production from both CD4 + and CD8 + T cells. These CD8 + T cells remained altered in the pancreatic islets long after B cell depletion and repopulation. Our findings suggest that B cell depletion can have an impact on T cell regulation, inducing a durable effect that is present long after repopulation. We suggest that this local effect of reducing autoimmune T cell activity contributes to delay in the onset of autoimmune diabetes.

  18. Human Adipose Tissue-Derived Mesenchymal Stem Cells Abrogate Plasmablast Formation and Induce Regulatory B Cells Independently of T Helper Cells

    NARCIS (Netherlands)

    Franquesa, M.; Mensah, F. K.; Huizinga, R.; Strini, T.; Boon, L.; Lombardo, E.; DelaRosa, O.; Laman, J. D.; Grinyo, J. M.; Weimar, W.; Betjes, M. G. H.; Baan, C. C.; Hoogduijn, M. J.

    Mesenchymal or stromal stem cells (MSC) interact with cells of the immune system in multiple ways. Modulation of the immune system by MSC is believed to be a therapeutic option for autoimmune disease and transplant rejection. In recent years, B cells have moved into the focus of the attention as

  19. Src Family Kinases Regulate Interferon Regulatory Factor 1 K63 Ubiquitination following Activation by TLR7/8 Vaccine Adjuvant in Human Monocytes and B Cells

    Directory of Open Access Journals (Sweden)

    Lorenza Tulli

    2018-03-01

    Full Text Available Toll-like receptors (TLRs play a key role in the activation of innate immune cells, in which their engagement leads to production of cytokines and co-stimulatory molecules. TLRs signaling requires recruitment of toll/IL-1R (TIR domain-containing adaptors, such as MyD88 and/or TRIF, and leads to activation of several transcription factors, such as NF-κB, the AP1 complex, and various members of the interferon regulatory factor (IRF family, which in turn results in triggering of several cellular functions associated with these receptors. A role for Src family kinases (SFKs in this signaling pathway has also been established. Our work and that of others have shown that this type of kinases is activated following engagement of several TLRs, and that this event is essential for the initiation of specific downstream cellular response. In particular, we have previously demonstrated that activation of SFKs is required for balanced production of pro-inflammatory cytokines by monocyte-derived dendritic cells after stimulation with R848, an agonist of human TLRs 7/8. We also showed that TLR7/8 triggering leads to an increase in interferon regulatory factor 1 (IRF-1 protein levels and that this effect is abolished by inhibition of SFKs, suggesting a critical role of these kinases in IRF-1 regulation. In this study, we first confirmed the key role of SFKs in TLR7/8 signaling for cytokine production and accumulation of IRF-1 protein in monocytes and in B lymphocytes, two other type of antigen-presenting cells. Then, we demonstrate that TLR7 triggering leads to an increase of K63-linked ubiquitination of IRF-1, which is prevented by SFKs inhibition, suggesting a key role of these kinases in posttranslational regulation of IRF-1 in the immune cells. In order to understand the mechanism that links SFKs activation to IRF-1 K63-linked ubiquitination, we examined SFKs and IRF-1 possible interactors and proved that activation of SFKs is necessary for their

  20. Impaired B cell development in the absence of Krüppel-like factor 3.

    Science.gov (United States)

    Vu, Thi Thanh; Gatto, Dominique; Turner, Vivian; Funnell, Alister P W; Mak, Ka Sin; Norton, Laura J; Kaplan, Warren; Cowley, Mark J; Agenès, Fabien; Kirberg, Jörg; Brink, Robert; Pearson, Richard C M; Crossley, Merlin

    2011-11-15

    Krüppel-like factor 3 (Klf3) is a member of the Klf family of transcription factors. Klfs are widely expressed and have diverse roles in development and differentiation. In this study, we examine the function of Klf3 in B cell development by studying B lymphopoiesis in a Klf3 knockout mouse model. We show that B cell differentiation is significantly impaired in the bone marrow, spleen, and peritoneal cavity of Klf3 null mice and confirm that the defects are cell autonomous. In the bone marrow, there is a reduction in immature B cells, whereas recirculating mature cells are noticeably increased. Immunohistology of the spleen reveals a poorly structured marginal zone (MZ) that may in part be caused by deregulation of adhesion molecules on MZ B cells. In the peritoneal cavity, there are significant defects in B1 B cell development. We also report that the loss of Klf3 in MZ B cells is associated with reduced BCR signaling strength and an impaired ability to respond to LPS stimulation. Finally, we show increased expression of a number of Klf genes in Klf3 null B cells, suggesting that a Klf regulatory network may exist in B cells.

  1. Human B cells induce dendritic cell maturation and favour Th2 polarization by inducing OX-40 ligand

    Science.gov (United States)

    Maddur, Mohan S.; Sharma, Meenu; Hegde, Pushpa; Stephen-Victor, Emmanuel; Pulendran, Bali; Kaveri, Srini V.; Bayry, Jagadeesh

    2015-01-01

    Dendritic cells (DCs) play a critical role in immune homeostasis by regulating the functions of various immune cells, including T and B cells. Notably, DCs also undergo education on reciprocal signalling by these immune cells and environmental factors. Various reports demonstrated that B cells have profound regulatory functions, although only few reports have explored the regulation of human DCs by B cells. Here we demonstrate that activated but not resting B cells induce maturation of DCs with distinct features to polarize Th2 cells that secrete interleukin (IL)-5, IL-4 and IL-13. B-cell-induced maturation of DCs is contact dependent and implicates signalling of B-cell activation molecules CD69, B-cell-activating factor receptor, and transmembrane activator and calcium-modulating cyclophilin ligand interactor. Mechanistically, differentiation of Th2 cells by B-cell-matured DCs is dependent on OX-40 ligand. Collectively, our results suggest that B cells have the ability to control their own effector functions by enhancing the ability of human DCs to mediate Th2 differentiation. PMID:24910129

  2. Anti-CD20 B-cell depletion enhances monocyte reactivity in neuroimmunological disorders

    Directory of Open Access Journals (Sweden)

    Hohlfeld Reinhard

    2011-10-01

    Full Text Available Abstract Background Clinical trials evaluating anti-CD20-mediated B-cell depletion in multiple sclerosis (MS and neuromyelitis optica (NMO generated encouraging results. Our recent studies in the MS model experimental autoimmune encephalomyelitis (EAE attributed clinical benefit to extinction of activated B-cells, but cautioned that depletion of naïve B-cells may be undesirable. We elucidated the regulatory role of un-activated B-cells in EAE and investigated whether anti-CD20 may collaterally diminish regulatory B-cell properties in treatment of neuroimmunological disorders. Methods Myelin oligodendrocyte glycoprotein (MOG peptide-immunized C57Bl/6 mice were depleted of B-cells. Functional consequences for regulatory T-cells (Treg and cytokine production of CD11b+ antigen presenting cells (APC were assessed. Peripheral blood mononuclear cells from 22 patients receiving anti-CD20 and 23 untreated neuroimmunological patients were evaluated for frequencies of B-cells, T-cells and monocytes; monocytic reactivity was determined by TNF-production and expression of signalling lymphocytic activation molecule (SLAM. Results We observed that EAE-exacerbation upon depletion of un-activated B-cells closely correlated with an enhanced production of pro-inflammatory TNF by CD11b+ APC. Paralleling this pre-clinical finding, anti-CD20 treatment of human neuroimmunological disorders increased the relative frequency of monocytes and accentuated pro-inflammatory monocyte function; when reactivated ex vivo, a higher frequency of monocytes from B-cell depleted patients produced TNF and expressed the activation marker SLAM. Conclusions These data suggest that in neuroimmunological disorders, pro-inflammatory APC activity is controlled by a subset of B-cells which is eliminated concomitantly upon anti-CD20 treatment. While this observation does not conflict with the general concept of B-cell depletion in human autoimmunity, it implies that its safety and

  3. Lipid rafts and B cell signaling.

    Science.gov (United States)

    Gupta, Neetu; DeFranco, Anthony L

    2007-10-01

    B cells comprise an essential component of the humoral immune system. They are equipped with the unique ability to synthesize and secrete pathogen-neutralizing antibodies, and share with professional antigen presenting cells the ability to internalize foreign antigens, and process them for presentation to helper T cells. Recent evidence indicates that specialized cholesterol- and glycosphingolipid-rich microdomains in the plasma membrane commonly referred to as lipid rafts, serve to compartmentalize key signaling molecules during the different stages of B cell activation including B cell antigen receptor (BCR)-initiated signal transduction, endocytosis of BCR-antigen complexes, loading of antigenic peptides onto MHC class II molecules, MHC-II associated antigen presentation to helper T cells, and receipt of helper signals via the CD40 receptor. Here we review the recent literature arguing for a role of lipid rafts in the spatial organization of B cell function.

  4. B Cells and B Cell Blasts Withstand Cryopreservation While Retaining Their Functionality for Producing Antibody

    Directory of Open Access Journals (Sweden)

    Philipp Fecher

    2018-05-01

    Full Text Available In individuals who have once developed humoral immunity to an infectious/foreign antigen, the antibodies present in their body can mediate instant protection when the antigen re-enters. Such antigen-specific antibodies can be readily detected in the serum. Long term humoral immunity is, however, also critically dependent on the ability of memory B cells to engage in a secondary antibody response upon re-exposure to the antigen. Antibody molecules in the body are short lived, having a half-life of weeks, while memory B cells have a life span of decades. Therefore, the presence of serum antibodies is not always a reliable indicator of B cell memory and comprehensive monitoring of humoral immunity requires that both serum antibodies and memory B cells be assessed. The prevailing view is that resting memory B cells and B cell blasts in peripheral blood mononuclear cells (PBMC cannot be cryopreserved without losing their antibody secreting function, and regulated high throughput immune monitoring of B cell immunity is therefore confined to—and largely limited by—the need to test freshly isolated PBMC. Using optimized protocols for freezing and thawing of PBMC, and four color ImmunoSpot® analysis for the simultaneous detection of all immunoglobulin classes/subclasses we show here that both resting memory B cells and B cell blasts retain their ability to secrete antibody after thawing, and thus demonstrate the feasibility of B cell immune monitoring using cryopreserved PBMC.

  5. B Cells and B Cell Blasts Withstand Cryopreservation While Retaining Their Functionality for Producing Antibody.

    Science.gov (United States)

    Fecher, Philipp; Caspell, Richard; Naeem, Villian; Karulin, Alexey Y; Kuerten, Stefanie; Lehmann, Paul V

    2018-05-31

    In individuals who have once developed humoral immunity to an infectious/foreign antigen, the antibodies present in their body can mediate instant protection when the antigen re-enters. Such antigen-specific antibodies can be readily detected in the serum. Long term humoral immunity is, however, also critically dependent on the ability of memory B cells to engage in a secondary antibody response upon re-exposure to the antigen. Antibody molecules in the body are short lived, having a half-life of weeks, while memory B cells have a life span of decades. Therefore, the presence of serum antibodies is not always a reliable indicator of B cell memory and comprehensive monitoring of humoral immunity requires that both serum antibodies and memory B cells be assessed. The prevailing view is that resting memory B cells and B cell blasts in peripheral blood mononuclear cells (PBMC) cannot be cryopreserved without losing their antibody secreting function, and regulated high throughput immune monitoring of B cell immunity is therefore confined to-and largely limited by-the need to test freshly isolated PBMC. Using optimized protocols for freezing and thawing of PBMC, and four color ImmunoSpot ® analysis for the simultaneous detection of all immunoglobulin classes/subclasses we show here that both resting memory B cells and B cell blasts retain their ability to secrete antibody after thawing, and thus demonstrate the feasibility of B cell immune monitoring using cryopreserved PBMC.

  6. [Proportion and significance of CD1d(hi)CD5⁺CD19⁺ regulatory B cell in peripheral blood of patients with neuromyelitis optica].

    Science.gov (United States)

    Yang, Fen; Huang, Dehui; Cheng, Chen; Wu, Weiping

    2015-03-01

    To detect the proportion of CD1d(hi)CD5⁺CD19⁺ regulatory B cells (Bregs) in peripheral blood of the patients with neuromyelitis optica (NMO), and explore whether CD1d(hi)CD5⁺CD19⁺ Bregs can play a role as a biomarker in the diagnosis of NMO versus multiple sclerosis (MS). Flow cytometry was performed to detect the proportion of CD1d(hi)CD5⁺CD19⁺ Bregs in peripheral blood from 44 cases of NMO, 38 cases of MS, and 30 healthy controls. The serum level of aquaporin-4 antibody (AQP4-Ab) of patients with NMO was detected by indirect immunofluorescence assay. The proportion of CD1d(hi)CD5⁺CD19⁺ Bregs in CD19⁺ B cells and lymphocytes was significantly lower in NMO group than in MS and control groups; however, there was no significant difference between MS group and control group. The proportion of CD1d(hi)CD5⁺CD19⁺ Bregs in CD19⁺ B cells and lymphocytes was lower in AQP4-Ab-positive NMO patients than in AQP4-Ab-negative NMO patients, and the difference was statistically significant. CD1d(hi)CD5⁺CD19⁺ Bregs may be a biomarker in the differential diagnosis of NMO versus MS.

  7. CD1d knockout mice exhibit aggravated contact hypersensitivity responses due to reduced interleukin-10 production predominantly by regulatory B cells

    DEFF Research Database (Denmark)

    Fjelbye, Jonas; Antvorskov, Julie C; Buschard, Karsten

    2015-01-01

    .05) and peritoneal cavity (80.8% decrease; P challenge, which suggests an important regulatory and protective role of CD1d-dependent NKT cells in CHS in our model, at least in part via regulation of IL-10 producing B(regs) ....... knockout (CD1d KO) and wild-type (Wt) mice after contact allergen exposure. For induction of CHS, C57BL/6 CD1d KO mice (n = 6) and C57BL/6 Wt mice (n = 6) were sensitised with 1% (w/v) dinitrochlorobenzene (DNCB) or vehicle for three consecutive days and subsequently challenged with a single dose of 0...

  8. Mansonella perstans microfilaremic individuals are characterized by enhanced type 2 helper T and regulatory T and B cell subsets and dampened systemic innate and adaptive immune responses.

    Directory of Open Access Journals (Sweden)

    Manuel Ritter

    2018-01-01

    Full Text Available The filarial nematode Mansonella perstans is endemic throughout Africa, northern South America and the Caribbean. Interestingly, M. perstans-infected individuals present no distinct clinical picture associated with certain pathology. Due to its relatively silent nature, research on this tropical disease has been neglected, especially M. perstans-driven immune responses. A hindrance in obtaining data on M. perstans-specific responses has been the inability to obtain adult worms since their habitats in serous cavities are difficult to access. Thus, in this study, for the first time, we used Mansonella perstans worm antigen extract as stimulant to obtain filarial-specific recall and immunoglobulin responses from M. perstans microfilaremic individuals (Mp MF+ from Cameroon. Moreover, systemic immune profiles in sera and immune cell composition in peripheral blood from Mp MF+ and amicrofilaremic individuals (Mp MF- were obtained. Our data reveal that Mp MF+ individuals showed significantly reduced cytokine (IL-4, IL-6 and IL-12p70 and chemokine levels (IL-8 and RANTES, but significantly higher MIP-1β as well as increased M. perstans-specific IgG4 levels compared to Mp MF- individuals. In contrast, upon re-stimulation with worm antigen extract, IFN-γ, IL-13, IL-10 and IL-17A secretion was enhanced in cell cultures from Mp MF+ individuals when compared to those from cultures of healthy European individuals. Moreover, analysis of immune cell composition in peripheral blood from Mp MF+ individuals revealed increased type 2 helper T (Th2, natural killer (NK, regulatory B and T cell (Breg and Treg subsets but decreased type 1 regulatory T (Tr1 cells. In summary, this study deciphers for the first time, M. perstans-specific immune responses using worm antigen extract and shows that patent M. perstans infections have distinct Th2, Breg and Treg subsets accompanied with reduced systemic innate and adaptive immune responses and dominant filarial-specific Ig

  9. Nitrogen modulation of legume root architecture signaling pathways involves phytohormones and small regulatory molecules.

    Science.gov (United States)

    Mohd-Radzman, Nadiatul A; Djordjevic, Michael A; Imin, Nijat

    2013-10-01

    Nitrogen, particularly nitrate is an important yield determinant for crops. However, current agricultural practice with excessive fertilizer usage has detrimental effects on the environment. Therefore, legumes have been suggested as a sustainable alternative for replenishing soil nitrogen. Legumes can uniquely form nitrogen-fixing nodules through symbiotic interaction with specialized soil bacteria. Legumes possess a highly plastic root system which modulates its architecture according to the nitrogen availability in the soil. Understanding how legumes regulate root development in response to nitrogen availability is an important step to improving root architecture. The nitrogen-mediated root development pathway starts with sensing soil nitrogen level followed by subsequent signal transduction pathways involving phytohormones, microRNAs and regulatory peptides that collectively modulate the growth and shape of the root system. This review focuses on the current understanding of nitrogen-mediated legume root architecture including local and systemic regulations by different N-sources and the modulations by phytohormones and small regulatory molecules.

  10. Dissecting the regulatory microenvironment of a large animal model of non-Hodgkin lymphoma: evidence of a negative prognostic impact of FOXP3+ T cells in canine B cell lymphoma.

    Directory of Open Access Journals (Sweden)

    Dammy Pinheiro

    Full Text Available The cancer microenvironment plays a pivotal role in oncogenesis, containing a number of regulatory cells that attenuate the anti-neoplastic immune response. While the negative prognostic impact of regulatory T cells (Tregs in the context of most solid tissue tumors is well established, their role in lymphoid malignancies remains unclear. T cells expressing FOXP3 and Helios were documented in the fine needle aspirates of affected lymph nodes of dogs with spontaneous multicentric B cell lymphoma (BCL, proposed to be a model for human non-Hodgkin lymphoma. Multivariable analysis revealed that the frequency of lymph node FOXP3(+ T cells was an independent negative prognostic factor, impacting both progression-free survival (hazard ratio 1.10; p = 0.01 and overall survival (hazard ratio 1.61; p = 0.01 when comparing dogs showing higher than the median FOXP3 expression with those showing the median value of FOXP3 expression or less. Taken together, these data suggest the existence of a population of Tregs operational in canine multicentric BCL that resembles thymic Tregs, which we speculate are co-opted by the tumor from the periphery. We suggest that canine multicentric BCL represents a robust large animal model of human diffuse large BCL, showing clinical, cytological and immunophenotypic similarities with the disease in man, allowing comparative studies of immunoregulatory mechanisms.

  11. What Are the Molecules Involved in Regulatory T-Cells Induction by Dendritic Cells in Cancer?

    Directory of Open Access Journals (Sweden)

    Rodrigo Nalio Ramos

    2013-01-01

    Full Text Available Dendritic cells (DCs are essential for the maintenance of homeostasis in the organism, and they do that by modulating lymphocyte priming, expansion, and response patterns according to signals they receive from the environment. The induction of suppressive lymphocytes by DCs is essential to hinder the development of autoimmune diseases but can be reverted against homeostasis when in the context of neoplasia. In this setting, the induction of suppressive or regulatory T cells contributes to the establishment of a state of tolerance towards the tumor, allowing it to grow unchecked by an otherwise functional immune system. Besides affecting its local environment, tumor also has been described as potent sources of anti-inflammatory/suppressive factors, which may act systemically, generating defects in the differentiation and maturation of immune cells, far beyond the immediate vicinity of the tumor mass. Cytokines, as IL-10 and TGF-beta, as well as cell surface molecules like PD-L1 and ICOS seem to be significantly involved in the redirection of DCs towards tolerance induction, and recent data suggest that tumor cells may, indeed, modulate distinct DCs subpopulations through the involvement of these molecules. It is to be expected that the identification of such molecules should provide molecular targets for more effective immunotherapeutic approaches to cancer.

  12. B cell biology: implications for treatment of systemic lupus erythematosus.

    Science.gov (United States)

    Anolik, J H

    2013-04-01

    utilization of B cell depletion therapy in autoimmune diseases and the need for new therapeutic approaches in SLE, a better understanding of human B cell subsets and the balance of pathogenic and regulatory functions is of the essence.

  13. Foxp1 controls mature B cell survival and the development of follicular and B-1 B cells

    Science.gov (United States)

    Patzelt, Thomas; Keppler, Selina J.; Gorka, Oliver; Thoene, Silvia; Wartewig, Tim; Reth, Michael; Förster, Irmgard; Lang, Roland; Buchner, Maike; Ruland, Jürgen

    2018-01-01

    The transcription factor Foxp1 is critical for early B cell development. Despite frequent deregulation of Foxp1 in B cell lymphoma, the physiological functions of Foxp1 in mature B cells remain unknown. Here, we used conditional gene targeting in the B cell lineage and report that Foxp1 disruption in developing and mature B cells results in reduced numbers and frequencies of follicular and B-1 B cells and in impaired antibody production upon T cell-independent immunization in vivo. Moreover, Foxp1-deficient B cells are impaired in survival even though they exhibit an increased capacity to proliferate. Transcriptional analysis identified defective expression of the prosurvival Bcl-2 family gene Bcl2l1 encoding Bcl-xl in Foxp1-deficient B cells, and we identified Foxp1 binding in the regulatory region of Bcl2l1. Transgenic overexpression of Bcl2 rescued the survival defect in Foxp1-deficient mature B cells in vivo and restored peripheral B cell numbers. Thus, our results identify Foxp1 as a physiological regulator of mature B cell survival mediated in part via the control of Bcl-xl expression and imply that this pathway might contribute to the pathogenic function of aberrant Foxp1 expression in lymphoma. PMID:29507226

  14. Changes in regulatory molecules for lymphangiogenesis in intestinal lymphangiectasia with enteric protein loss.

    Science.gov (United States)

    Hokari, Ryota; Kitagawa, Noritake; Watanabe, Chikako; Komoto, Shunsuke; Kurihara, Chie; Okada, Yoshikiyo; Kawaguchi, Atsushi; Nagao, Shigeaki; Hibi, Toshifumi; Miura, Soichiro

    2008-07-01

    Vascular endothelial growth factor receptor 3 (VEGFR3) and LYVE-1 are specifically expressed in the endothelium of the lymphatic systems. VEGF-C, D, FOXC2, Prox 1, and SOX18 are known to play central roles in lymphatic development. We investigated the expression of regulatory molecules for lymphangiogenesis in the duodenal mucosa of idiopathic intestinal lymphangiectasia. Biopsy samples were obtained from duodenal biopsies in patients with intestinal lymphangiectasia complicated with protein-losing from white spot lesions in which lymphangiectasia was histologically confirmed. Immunohistochemical analysis for VEGFR3 and LYVE-1 was performed. mRNA expression of VEGF-C, VEGF-D, VEGFR3, and transcription factors was determined by the quantitative reverse transcription-polymerase chain reaction method. In the control mucosa, VEGFR3 was weakly expressed on the central lymphatic vessels in the lamina propria and LYVE-1 was expressed mainly on the lymphatic vessels in the submucosa. In intestinal lymphangiectasia, VEGFR3 and LYVE-1 expression levels were increased on the mucosal surface corresponding to widely dilated lymphatic vessels, while they were decreased in the deeper mucosa. mRNA expression study showed a significant increase in the expression level of VEGFR3 in lymphangiectasia, but the expression of VEGF-C and -D mRNA was significantly suppressed compared with that in controls despite the presence of lymphangiectasia. The mRNA expression levels of FOXC2 and SOX18 were also decreased, whereas Prox 1 was not altered. There is an altered expression of regulatory molecules for lymphangiogenesis in the duodenal mucosa in these patients.

  15. Human B cells fail to secrete type I interferons upon cytoplasmic DNA exposure.

    Science.gov (United States)

    Gram, Anna M; Sun, Chenglong; Landman, Sanne L; Oosenbrug, Timo; Koppejan, Hester J; Kwakkenbos, Mark J; Hoeben, Rob C; Paludan, Søren R; Ressing, Maaike E

    2017-11-01

    Most cells are believed to be capable of producing type I interferons (IFN I) as part of an innate immune response against, for instance, viral infections. In macrophages, IFN I is potently induced upon cytoplasmic exposure to foreign nucleic acids. Infection of these cells with herpesviruses leads to triggering of the DNA sensors interferon-inducible protein 16 (IFI16) and cyclic GMP-AMP (cGAMP) synthase (cGAS). Thereby, the stimulator of interferon genes (STING) and the downstream molecules TANK-binding kinase 1 (TBK1) and interferon regulatory factor 3 (IRF3) are sequentially activated culminating in IFN I secretion. Human gamma-herpesviruses, such as Epstein-Barr virus (EBV), exploit B cells as a reservoir for persistent infection. In this study, we investigated whether human B cells, similar to macrophages, engage the cytoplasmic DNA sensing pathway to induce an innate immune response. We found that the B cells fail to secrete IFN I upon cytoplasmic DNA exposure, although they express the DNA sensors cGAS and IFI16 and the signaling components TBK1 and IRF3. In primary human B lymphocytes and EBV-negative B cell lines, this deficiency is explained by a lack of detectable levels of the central adaptor protein STING. In contrast, EBV-transformed B cell lines did express STING, yet both these lines as well as STING-reconstituted EBV-negative B cells did not produce IFN I upon dsDNA or cGAMP stimulation. Our combined data show that the cytoplasmic DNA sensing pathway is dysfunctional in human B cells. This exemplifies that certain cell types cannot induce IFN I in response to cytoplasmic DNA exposure providing a potential niche for viral persistence. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. Nitrogen modulation of legume root architecture signalling pathways involves phytohormones and small regulatory molecules

    Directory of Open Access Journals (Sweden)

    Nadiatul Akmal Mohd-Radzman

    2013-10-01

    Full Text Available Nitrogen, particularly nitrate is an important yield determinant for crops. However, current agricultural practice with excessive fertilizer usage has detrimental effects on the environment. Therefore, legumes have been suggested as a sustainable alternative for replenishing soil nitrogen. Legumes can uniquely form nitrogen-fixing nodules through symbiotic interaction with specialized soil bacteria. Legumes possess a highly plastic root system which modulates its architecture according to the nitrogen availability in the soil. Understanding how legumes regulate root development in response to nitrogen availability is an important step to improving root architecture. The nitrogen-mediated root development pathway starts with sensing soil nitrogen level followed by subsequent signal transduction pathways involving phytohormones, microRNAs and regulatory peptides that collectively modulate the growth and shape of the root system. This review focuses on the current understanding of nitrogen-mediated legume root architecture including local and systemic regulations by different N-sources and the modulations by phytohormones and small regulatory molecules.

  17. Interaction of Staphylococci with Human B cells.

    Directory of Open Access Journals (Sweden)

    Tyler K Nygaard

    Full Text Available Staphylococcus aureus is a leading cause of human infections worldwide. The pathogen produces numerous molecules that can interfere with recognition and binding by host innate immune cells, an initial step required for the ingestion and subsequent destruction of microbes by phagocytes. To better understand the interaction of this pathogen with human immune cells, we compared the association of S. aureus and S. epidermidis with leukocytes in human blood. We found that a significantly greater proportion of B cells associated with S. epidermidis relative to S. aureus. Complement components and complement receptors were important for the binding of B cells with S. epidermidis. Experiments using staphylococci inactivated by ultraviolet radiation and S. aureus isogenic deletion mutants indicated that S. aureus secretes molecules regulated by the SaeR/S two-component system that interfere with the ability of human B cells to bind this bacterium. We hypothesize that the relative inability of B cells to bind S. aureus contributes to the microbe's success as a human pathogen.

  18. The Transcriptional Coactivator Bob1 Is Associated With Pathologic B Cell Responses in Autoimmune Tissue Inflammation

    NARCIS (Netherlands)

    Levels, Maria J.; Van Tok, Melissa N.; Cantaert, Tineke; Canete, Juan D.; Kroese, Frans G. M.; Germar, Kristine; Spits, Hergen; Baeten, Dominique L. P.; Yeremenko, Nataliya G.

    Objective. The molecular mechanisms steering abnormal B cell responses in autoimmune diseases remain poorly understood. We undertook this study to identify molecular switches controlling pathologic B cell responses in rheumatoid arthritis (RA). Methods. Candidate molecules were identified by gene

  19. Increased frequency of circulating CD19+CD24hiCD38hi B cells with regulatory capacity in patients with Ankylosing spondylitis (AS naïve for biological agents.

    Directory of Open Access Journals (Sweden)

    María-Belén Bautista-Caro

    Full Text Available Our objective was to study the frequency of circulating CD19+CD24hiCD38hi B cells (Breg in AS patients. To this end, peripheral blood was drawn from AS patients naïve for TNF blockers (AS/nb (n = 42 and healthy controls (HC (n = 42. Six patients donated blood for a second time, 6 months after initiating treatment with anti-TNFα drugs. After isolation by Ficoll-Hypaque, PBMCs were stained with antibodies to CD3, CD4, CD19, CD24, and CD38, and examined by cytometry. For functional studies, total CD19+ B cells were isolated from PBMCs of 3 HC by magnetical sorting. Breg-depleted CD19+ B cells were obtained after CD19+CD24hiCD38hi B cells were removed from total CD19+ cells by cytometry. Total CD19+ B cells or Breg-depleted CD19+ B cells were established in culture and stimulated through their BCR. Secretion of IFNγ was determined by ELISA in culture supernatants. When compared with HC, AS/nb patients demonstrated a significantly increased frequency of Breg cells, which was independent of disease activity. Anti-TNFα drugs induced a significant reduction of circulating Breg numbers, which were no longer elevated after six months of treatment. Functional in vitro studies showed that the secretion of IFNγ was significantly higher in Breg-depleted as compared with total CD19+ B cells, indicating that Breg can downmodulate B cell pro-inflammatory cytokine secretion. In summary, an increased frequency of circulating CD19+CD24hiCD38hi B cells is observed in AS/nb patients, that is not related with disease activity; anti-TNFα drugs are able to downmodulate circulating Breg numbers in AS.

  20. Imbalanced expression of functional surface molecules in regulatory and effector T cells in systemic lupus erythematosus

    Energy Technology Data Exchange (ETDEWEB)

    Mesquita Júnior, D. [Disciplina de Reumatologia, Departamento de Medicina, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP (Brazil); Cruvinel, W.M. [Disciplina de Reumatologia, Departamento de Medicina, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP (Brazil); Departamento de Biomedicina, Universidade Católica de Goiás, Goiânia, GO (Brazil); Araujo, J.A.P. [Disciplina de Reumatologia, Departamento de Medicina, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP (Brazil); Salmazi, K.C.; Kallas, E.G. [Disciplina de Imunologia Clínica e Alergia, Departamento de Clínica Médica, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Andrade, L.E.C. [Disciplina de Reumatologia, Departamento de Medicina, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP (Brazil)

    2014-08-22

    Regulatory T (TREG) cells play an important role in maintaining immune tolerance and avoiding autoimmunity. We analyzed the expression of membrane molecules in TREG and effector T cells in systemic lupus erythematosus (SLE). TREG and effector T cells were analyzed for the expression of CTLA-4, PD1, CD28, CD95, GITR, HLA-DR, OX40, CD40L, and CD45RO in 26 patients with active disease, 31 with inactive disease, and 26 healthy controls. TREG cells were defined as CD25{sup +/high}CD127{sup Ø/low}FoxP3{sup +}, and effector T cells were defined as CD25{sup +}CD127{sup +}FoxP3{sup Ø}. The ratio of TREG to effector T cells expressing GITR, PD1, HLA-DR, OX40, CD40L, and CD45RO was determined in the three groups. The frequency of TREG cells was similar in patients with SLE and controls. However, SLE patients had a decreased frequency of CTLA-4{sup +}TREG and CD28{sup +}TREG cells and an increased frequency of CD40L{sup +}TREG cells. There was a decrease in the TREG/effector-T ratio for GITR{sup +}, HLA-DR{sup +}, OX40{sup +}, and CD45RO{sup +} cells, and an increased ratio of TREG/effector-T CD40L{sup +} cells in patients with SLE. In addition, CD40L{sup +}TREG cell frequency correlated with the SLE disease activity index (P=0.0163). In conclusion, our findings showed several abnormalities in the expression of functionally critical surface molecules in TREG and effector T cells in SLE that may be relevant to the pathogenesis of this disease.

  1. Imbalanced expression of functional surface molecules in regulatory and effector T cells in systemic lupus erythematosus

    International Nuclear Information System (INIS)

    Mesquita Júnior, D.; Cruvinel, W.M.; Araujo, J.A.P.; Salmazi, K.C.; Kallas, E.G.; Andrade, L.E.C.

    2014-01-01

    Regulatory T (TREG) cells play an important role in maintaining immune tolerance and avoiding autoimmunity. We analyzed the expression of membrane molecules in TREG and effector T cells in systemic lupus erythematosus (SLE). TREG and effector T cells were analyzed for the expression of CTLA-4, PD1, CD28, CD95, GITR, HLA-DR, OX40, CD40L, and CD45RO in 26 patients with active disease, 31 with inactive disease, and 26 healthy controls. TREG cells were defined as CD25 +/high CD127 Ø/low FoxP3 + , and effector T cells were defined as CD25 + CD127 + FoxP3 Ø . The ratio of TREG to effector T cells expressing GITR, PD1, HLA-DR, OX40, CD40L, and CD45RO was determined in the three groups. The frequency of TREG cells was similar in patients with SLE and controls. However, SLE patients had a decreased frequency of CTLA-4 + TREG and CD28 + TREG cells and an increased frequency of CD40L + TREG cells. There was a decrease in the TREG/effector-T ratio for GITR + , HLA-DR + , OX40 + , and CD45RO + cells, and an increased ratio of TREG/effector-T CD40L + cells in patients with SLE. In addition, CD40L + TREG cell frequency correlated with the SLE disease activity index (P=0.0163). In conclusion, our findings showed several abnormalities in the expression of functionally critical surface molecules in TREG and effector T cells in SLE that may be relevant to the pathogenesis of this disease

  2. MicroRNA expression in nodal and extranodal Diffuse Large B-cell Lymphoma

    DEFF Research Database (Denmark)

    Mandrup, Charlotte; Petersen, Anders; Højfeldt, Anne Dirks

    MicroRNA expression in nodal and extranodal Diffuse Large B-cell Lymphoma   C. Mandrup1, A. Petersen1, A. D. Hoejfeldt1, H. F. Thomsen1, J. Madsen1, J. Dahlgaard1, P. Johansen2, A. Bukh1, K. Dybkaer1 and H. E Johnsen1. 1Department of Hematology, 2Pathological Institute, Aalborg Hospital, Aarhus...... University Hospital, Aalborg, Denmark Introduction: The aim of this project was to analyse microRNA (miRNA) expression in nodal and extranodal diffuse large B-cell lymphoma (DLBCL). Manifestation at diagnosis may be nodal and/or extranodal. At present, there are no known determinants for none...... of the manifestations, and no way to predict the potential progression from nodal to extranodal disease. miRNA are small regulatory RNA molecules with core function to repress/cleave sequence complementary mRNA targets. Abnormalities in miRNA genetics and expression are known to affect initiation and development...

  3. How B cells influence bone biology in health and disease.

    Science.gov (United States)

    Horowitz, Mark C; Fretz, Jackie A; Lorenzo, Joseph A

    2010-09-01

    It is now well established that important regulatory interactions occur between the cells in the hematopoietic, immune and skeletal systems (osteoimmunology). B lymphocytes (B cells) are responsible for the generation and production of antibodies or immunoglobulins in the body. Together with T cells these lymphocytes comprise the adaptive immune system, which allows an individual to develop specific responses to an infection and retain memory of that infection, allowing for a faster and more robust response if that same infection occurs again. In addition to this immune function, B cells have a close and multifaceted relationship with bone cells. B cells differentiate from hematopoietic stem cells (HSCs) in supportive niches found on endosteal bone surfaces. Cells in the osteoblast lineage support HSC and B cell differentiation in these niches. B cell differentiation is regulated, at least in part, by a series of transcription factors that function in a temporal manner. While these transcription factors are required for B cell differentiation, their loss causes profound changes in the bone phenotype. This is due, in part, to the close relationship between macrophage/osteoclast and B cell differentiation. Cross talk between B cells and bone cells is reciprocal with defects in the RANKL-RANK, OPG signaling axis resulting in altered bone phenotypes. While the role of B cells during normal bone remodeling appears minimal, activated B cells play an important role in many inflammatory diseases with associated bony changes. This review examines the relationship between B cells and bone cells and how that relationship affects the skeleton and hematopoiesis during health and disease. Copyright 2010 Elsevier Inc. All rights reserved.

  4. The B-Cell Follicle in HIV Infection: Barrier to a Cure.

    Science.gov (United States)

    Bronnimann, Matthew P; Skinner, Pamela J; Connick, Elizabeth

    2018-01-01

    The majority of HIV replication occurs in secondary lymphoid organs (SLOs) such as the spleen, lymph nodes, and gut-associated lymphoid tissue. Within SLOs, HIV RNA + cells are concentrated in the B-cell follicle during chronic untreated infection, and emerging data suggest that they are a major source of replication in treated disease as well. The concentration of HIV RNA + cells in the B-cell follicle is mediated by several factors. Follicular CD4 + T-cell subsets including T-follicular helper cells and T-follicular regulatory cells are significantly more permissive to HIV than extrafollicular subsets. The B cell follicle also contains a large reservoir of extracellular HIV virions, which accumulate on the surface of follicular dendritic cells (FDCs) in germinal centers. FDC-bound HIV virions remain infectious even in the presence of neutralizing antibodies and can persist for months or even years. Moreover, the B-cell follicle is semi-immune privileged from CTL control. Frequencies of HIV- and SIV-specific CTL are lower in B-cell follicles compared to extrafollicular regions as the majority of CTL do not express the follicular homing receptor CXCR5. Additionally, CTL in the B-cell follicle may be less functional than extrafollicular CTL as many exhibit the recently described CD8 T follicular regulatory phenotype. Other factors may also contribute to the follicular concentration of HIV RNA + cells. Notably, the contribution of NK cells and γδ T cells to control and/or persistence of HIV RNA + cells in secondary lymphoid tissue remains poorly characterized. As HIV research moves increasingly toward the development of cure strategies, a greater understanding of the barriers to control of HIV infection in B-cell follicles is critical. Although no strategy has as of yet proven to be effective, a range of novel therapies to address these barriers are currently being investigated including genetically engineered CTL or chimeric antigen receptor T cells that express

  5. The B-Cell Follicle in HIV Infection: Barrier to a Cure

    Directory of Open Access Journals (Sweden)

    Matthew P. Bronnimann

    2018-01-01

    Full Text Available The majority of HIV replication occurs in secondary lymphoid organs (SLOs such as the spleen, lymph nodes, and gut-associated lymphoid tissue. Within SLOs, HIV RNA+ cells are concentrated in the B-cell follicle during chronic untreated infection, and emerging data suggest that they are a major source of replication in treated disease as well. The concentration of HIV RNA+ cells in the B-cell follicle is mediated by several factors. Follicular CD4+ T-cell subsets including T-follicular helper cells and T-follicular regulatory cells are significantly more permissive to HIV than extrafollicular subsets. The B cell follicle also contains a large reservoir of extracellular HIV virions, which accumulate on the surface of follicular dendritic cells (FDCs in germinal centers. FDC-bound HIV virions remain infectious even in the presence of neutralizing antibodies and can persist for months or even years. Moreover, the B-cell follicle is semi-immune privileged from CTL control. Frequencies of HIV- and SIV-specific CTL are lower in B-cell follicles compared to extrafollicular regions as the majority of CTL do not express the follicular homing receptor CXCR5. Additionally, CTL in the B-cell follicle may be less functional than extrafollicular CTL as many exhibit the recently described CD8 T follicular regulatory phenotype. Other factors may also contribute to the follicular concentration of HIV RNA+ cells. Notably, the contribution of NK cells and γδ T cells to control and/or persistence of HIV RNA+ cells in secondary lymphoid tissue remains poorly characterized. As HIV research moves increasingly toward the development of cure strategies, a greater understanding of the barriers to control of HIV infection in B-cell follicles is critical. Although no strategy has as of yet proven to be effective, a range of novel therapies to address these barriers are currently being investigated including genetically engineered CTL or chimeric antigen receptor T cells

  6. Spatial and functional restriction of regulatory molecules during mammalian myoblast fusion

    International Nuclear Information System (INIS)

    Pavlath, Grace K.

    2010-01-01

    Myoblast fusion is a highly regulated process that is key for forming skeletal muscle during development and regeneration in mammals. Much remains to be understood about the molecular regulation of myoblast fusion. Some molecules that influence mammalian muscle fusion display specific cellular localization during myogenesis. Such molecules can be localized to the contact region between two fusing cells either in both cells or only in one of the cells. How distinct localization of molecules contributes to fusion is not clear. Further complexity exists as other molecules are functionally restricted to myoblasts at later stages of myogenesis to regulate their fusion with multinucleated myotubes. This review examines these three categories of molecules and discusses how spatial and functional restriction may contribute to the formation of a multinucleated cell. Understanding how and why molecules become restricted in location or function is likely to provide further insights into the mechanisms regulating mammalian muscle fusion.

  7. Dataset of transcriptional landscape of B cell early activation

    Directory of Open Access Journals (Sweden)

    Alexander S. Garruss

    2015-09-01

    Full Text Available Signaling via B cell receptors (BCR and Toll-like receptors (TLRs result in activation of B cells with distinct physiological outcomes, but transcriptional regulatory mechanisms that drive activation and distinguish these pathways remain unknown. At early time points after BCR and TLR ligand exposure, 0.5 and 2 h, RNA-seq was performed allowing observations on rapid transcriptional changes. At 2 h, ChIP-seq was performed to allow observations on important regulatory mechanisms potentially driving transcriptional change. The dataset includes RNA-seq, ChIP-seq of control (Input, RNA Pol II, H3K4me3, H3K27me3, and a separate RNA-seq for miRNA expression, which can be found at Gene Expression Omnibus Dataset GSE61608. Here, we provide details on the experimental and analysis methods used to obtain and analyze this dataset and to examine the transcriptional landscape of B cell early activation.

  8. Apoptosis following interleukin-2 withdrawal from T cells: evidence for a regulatory role of CD18 (beta 2-integrin) molecules

    DEFF Research Database (Denmark)

    Röpke, C; Gladstone, P; Nielsen, M

    1996-01-01

    , these findings suggest that CD18 molecules (beta 2-integrins) play a regulatory role in the apoptotic response following cytokine withdrawal, and that the regulation is mediated, at least partly, through T-T cell interactions. Thus, apoptotic death following IL-2 deprivation appears to be under "social" control...... activated T cells. Thus, removal of IL-2 from proliferating T cells not only induces growth arrest, but triggers a massive cell death due to apoptosis. While the apoptotic response involves a series of well-described events, it remains less clear how apoptosis is regulated following IL-2 withdrawal. Here...... molecules (CD28, CD29, CD49d, CD80, CD86) did not. Secondly, IL-2 withdrawal resulted in a retarded apoptotic response in LFA-1 (CD11a/CD18) negative T cells obtained from a leukocyte adhesion deficiency (LAD) patient, as compared to LFA-1 positive T cell lines. Thirdly, co-culture of LFA-1 positive...

  9. B-Cell-Specific Diversion of Glucose Carbon Utilization Reveals a Unique Vulnerability in B Cell Malignancies.

    Science.gov (United States)

    Xiao, Gang; Chan, Lai N; Klemm, Lars; Braas, Daniel; Chen, Zhengshan; Geng, Huimin; Zhang, Qiuyi Chen; Aghajanirefah, Ali; Cosgun, Kadriye Nehir; Sadras, Teresa; Lee, Jaewoong; Mirzapoiazova, Tamara; Salgia, Ravi; Ernst, Thomas; Hochhaus, Andreas; Jumaa, Hassan; Jiang, Xiaoyan; Weinstock, David M; Graeber, Thomas G; Müschen, Markus

    2018-04-05

    B cell activation during normal immune responses and oncogenic transformation impose increased metabolic demands on B cells and their ability to retain redox homeostasis. While the serine/threonine-protein phosphatase 2A (PP2A) was identified as a tumor suppressor in multiple types of cancer, our genetic studies revealed an essential role of PP2A in B cell tumors. Thereby, PP2A redirects glucose carbon utilization from glycolysis to the pentose phosphate pathway (PPP) to salvage oxidative stress. This unique vulnerability reflects constitutively low PPP activity in B cells and transcriptional repression of G6PD and other key PPP enzymes by the B cell transcription factors PAX5 and IKZF1. Reflecting B-cell-specific transcriptional PPP-repression, glucose carbon utilization in B cells is heavily skewed in favor of glycolysis resulting in lack of PPP-dependent antioxidant protection. These findings reveal a gatekeeper function of the PPP in a broad range of B cell malignancies that can be efficiently targeted by small molecule inhibition of PP2A and G6PD. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Suppression of complement regulatory protein C1 inhibitor in vascular endothelial activation by inhibiting vascular cell adhesion molecule-1 action

    International Nuclear Information System (INIS)

    Zhang, Haimou; Qin, Gangjian; Liang, Gang; Li, Jinan; Chiu, Isaac; Barrington, Robert A.; Liu, Dongxu

    2007-01-01

    Increased expression of adhesion molecules by activated endothelium is a critical feature of vascular inflammation associated with the several diseases such as endotoxin shock and sepsis/septic shock. Our data demonstrated complement regulatory protein C1 inhibitor (C1INH) prevents endothelial cell injury. We hypothesized that C1INH has the ability of an anti-endothelial activation associated with suppression of expression of adhesion molecule(s). C1INH blocked leukocyte adhesion to endothelial cell monolayer in both static assay and flow conditions. In inflammatory condition, C1INH reduced vascular cell adhesion molecule (VCAM-1) expression associated with its cytoplasmic mRNA destabilization and nuclear transcription level. Studies exploring the underlying mechanism of C1INH-mediated suppression in VCAM-1 expression were related to reduction of NF-κB activation and nuclear translocation in an IκBα-dependent manner. The inhibitory effects were associated with reduction of inhibitor IκB kinase activity and stabilization of the NF-κB inhibitor IκB. These findings indicate a novel role for C1INH in inhibition of vascular endothelial activation. These observations could provide the basis for new therapeutic application of C1INH to target inflammatory processes in different pathologic situations

  11. A method for selecting cis-acting regulatory sequences that respond to small molecule effectors

    Directory of Open Access Journals (Sweden)

    Allas Ülar

    2010-08-01

    Full Text Available Abstract Background Several cis-acting regulatory sequences functioning at the level of mRNA or nascent peptide and specifically influencing transcription or translation have been described. These regulatory elements often respond to specific chemicals. Results We have developed a method that allows us to select cis-acting regulatory sequences that respond to diverse chemicals. The method is based on the β-lactamase gene containing a random sequence inserted into the beginning of the ORF. Several rounds of selection are used to isolate sequences that suppress β-lactamase expression in response to the compound under study. We have isolated sequences that respond to erythromycin, troleandomycin, chloramphenicol, meta-toluate and homoserine lactone. By introducing synonymous and non-synonymous mutations we have shown that at least in the case of erythromycin the sequences act at the peptide level. We have also tested the cross-activities of the constructs and found that in most cases the sequences respond most strongly to the compound on which they were isolated. Conclusions Several selected peptides showed ligand-specific changes in amino acid frequencies, but no consensus motif could be identified. This is consistent with previous observations on natural cis-acting peptides, showing that it is often impossible to demonstrate a consensus. Applying the currently developed method on a larger scale, by selecting and comparing an extended set of sequences, might allow the sequence rules underlying the activity of cis-acting regulatory peptides to be identified.

  12. Human Memory B Cells in Healthy Gingiva, Gingivitis, and Periodontitis.

    Science.gov (United States)

    Mahanonda, Rangsini; Champaiboon, Chantrakorn; Subbalekha, Keskanya; Sa-Ard-Iam, Noppadol; Rattanathammatada, Warattaya; Thawanaphong, Saranya; Rerkyen, Pimprapa; Yoshimura, Fuminobu; Nagano, Keiji; Lang, Niklaus P; Pichyangkul, Sathit

    2016-08-01

    The presence of inflammatory infiltrates with B cells, specifically plasma cells, is the hallmark of periodontitis lesions. The composition of these infiltrates in various stages of homeostasis and disease development is not well documented. Human tissue biopsies from sites with gingival health (n = 29), gingivitis (n = 8), and periodontitis (n = 21) as well as gingival tissue after treated periodontitis (n = 6) were obtained and analyzed for their composition of B cell subsets. Ag specificity, Ig secretion, and expression of receptor activator of NF-κB ligand and granzyme B were performed. Although most of the B cell subsets in healthy gingiva and gingivitis tissues were CD19(+)CD27(+)CD38(-) memory B cells, the major B cell component in periodontitis was CD19(+)CD27(+)CD38(+)CD138(+)HLA-DR(low) plasma cells, not plasmablasts. Plasma cell aggregates were observed at the base of the periodontal pocket and scattered throughout the gingiva, especially apically toward the advancing front of the lesion. High expression of CXCL12, a proliferation-inducing ligand, B cell-activating factor, IL-10, IL-6, and IL-21 molecules involved in local B cell responses was detected in both gingivitis and periodontitis tissues. Periodontitis tissue plasma cells mainly secreted IgG specific to periodontal pathogens and also expressed receptor activator of NF-κB ligand, a bone resorption cytokine. Memory B cells resided in the connective tissue subjacent to the junctional epithelium in healthy gingiva. This suggested a role of memory B cells in maintaining periodontal homeostasis. Copyright © 2016 by The American Association of Immunologists, Inc.

  13. The cell biology of T-dependent B cell activation

    DEFF Research Database (Denmark)

    Owens, T; Zeine, R

    1989-01-01

    The requirement that CD4+ helper T cells recognize antigen in association with class II Major Histocompatibility Complex (MHC) encoded molecules constrains T cells to activation through intercellular interaction. The cell biology of the interactions between CD4+ T cells and antigen-presenting cells...... includes multipoint intermolecular interactions that probably involve aggregation of both polymorphic and monomorphic T cell surface molecules. Such aggregations have been shown in vitro to markedly enhance and, in some cases, induce T cell activation. The production of T-derived lymphokines that have been...... implicated in B cell activation is dependent on the T cell receptor for antigen and its associated CD3 signalling complex. T-dependent help for B cell activation is therefore similarly MHC-restricted and involves T-B intercellular interaction. Recent reports that describe antigen-independent B cell...

  14. Identification of a regulatory T cell specific cell surface molecule that mediates suppressive signals and induces Foxp3 expression.

    Science.gov (United States)

    Wang, Rui; Wan, Qi; Kozhaya, Lina; Fujii, Hodaka; Unutmaz, Derya

    2008-07-16

    Regulatory T (T(reg)) cells control immune activation and maintain tolerance. How T(regs) mediate their suppressive function is unclear. Here we identified a cell surface molecule, called GARP, (or LRRC32), which within T cells is specifically expressed in T(regs) activated through the T cell receptor (TCR). Ectopic expression of GARP in human naïve T (T(N)) cells inhibited their proliferation and cytokine secretion upon TCR activation. Remarkably, GARP over-expression in T(N) cells induced expression of T(reg) master transcription factor Foxp3 and endowed them with a partial suppressive function. The extracellular but not the cytoplasmic region of GARP, was necessary for these functions. Silencing Foxp3 in human T(reg) cells reduced expression of GARP and attenuated their suppressive function. However, GARP function was not affected when Foxp3 was downregulated in GARP-overexpressing cells, while silencing GARP in Foxp3-overexpressing cells reduced their suppressive activity. These findings reveal a novel cell surface molecule-mediated regulatory mechanism, with implications for modulating aberrant immune responses.

  15. Identification of a regulatory T cell specific cell surface molecule that mediates suppressive signals and induces Foxp3 expression.

    Directory of Open Access Journals (Sweden)

    Rui Wang

    2008-07-01

    Full Text Available Regulatory T (T(reg cells control immune activation and maintain tolerance. How T(regs mediate their suppressive function is unclear. Here we identified a cell surface molecule, called GARP, (or LRRC32, which within T cells is specifically expressed in T(regs activated through the T cell receptor (TCR. Ectopic expression of GARP in human naïve T (T(N cells inhibited their proliferation and cytokine secretion upon TCR activation. Remarkably, GARP over-expression in T(N cells induced expression of T(reg master transcription factor Foxp3 and endowed them with a partial suppressive function. The extracellular but not the cytoplasmic region of GARP, was necessary for these functions. Silencing Foxp3 in human T(reg cells reduced expression of GARP and attenuated their suppressive function. However, GARP function was not affected when Foxp3 was downregulated in GARP-overexpressing cells, while silencing GARP in Foxp3-overexpressing cells reduced their suppressive activity. These findings reveal a novel cell surface molecule-mediated regulatory mechanism, with implications for modulating aberrant immune responses.

  16. Altered B cell homeostasis and Toll-like receptor 9-driven response in patients affected by autoimmune polyglandular syndrome Type 1: Altered B cell phenotype and dysregulation of the B cell function in APECED patients.

    Science.gov (United States)

    Perri, Valentina; Gianchecchi, Elena; Scarpa, Riccardo; Valenzise, Mariella; Rosado, Maria Manuela; Giorda, Ezio; Crinò, Antonino; Cappa, Marco; Barollo, Susi; Garelli, Silvia; Betterle, Corrado; Fierabracci, Alessandra

    2017-02-01

    APECED is a T-cell mediated disease with increased frequencies of CD8+ effector and reduction of FoxP3+ T regulatory cells. Antibodies against affected organs and neutralizing to cytokines are found in the peripheral blood. The contribution of B cells to multiorgan autoimmunity in Aire-/- mice was reported opening perspectives on the utility of anti-B cell therapy. We aimed to analyse the B cell phenotype of APECED patients compared to age-matched controls. FACS analysis was conducted on PBMC in basal conditions and following CpG stimulation. Total B and switched memory (SM) B cells were reduced while IgM memory were increased in patients. In those having more than 15 years from the first clinical manifestation the defect included also mature and transitional B cells; total memory B cells were increased, while SM were unaffected. In patients with shorter disease duration, total B cells were unaltered while SM and IgM memory behaved as in the total group. A defective B cell proliferation was detected after 4day-stimulation. In conclusion APECED patients show, in addition to a significant alteration of the B cell phenotype, a dysregulation of the B cell function involving peripheral innate immune mechanisms particularly those with longer disease duration. Copyright © 2016 Elsevier GmbH. All rights reserved.

  17. NKT Cell Responses to B Cell Lymphoma.

    Science.gov (United States)

    Li, Junxin; Sun, Wenji; Subrahmanyam, Priyanka B; Page, Carly; Younger, Kenisha M; Tiper, Irina V; Frieman, Matthew; Kimball, Amy S; Webb, Tonya J

    2014-06-01

    Natural killer T (NKT) cells are a unique subset of CD1d-restricted T lymphocytes that express characteristics of both T cells and natural killer cells. NKT cells mediate tumor immune-surveillance; however, NKT cells are numerically reduced and functionally impaired in lymphoma patients. Many hematologic malignancies express CD1d molecules and co-stimulatory proteins needed to induce anti-tumor immunity by NKT cells, yet most tumors are poorly immunogenic. In this study, we sought to investigate NKT cell responses to B cell lymphoma. In the presence of exogenous antigen, both mouse and human NKT cell lines produce cytokines following stimulation by B cell lymphoma lines. NKT cell populations were examined ex vivo in mouse models of spontaneous B cell lymphoma, and it was found that during early stages, NKT cell responses were enhanced in lymphoma-bearing animals compared to disease-free animals. In contrast, in lymphoma-bearing animals with splenomegaly and lymphadenopathy, NKT cells were functionally impaired. In a mouse model of blastoid variant mantle cell lymphoma, treatment of tumor-bearing mice with a potent NKT cell agonist, α-galactosylceramide (α-GalCer), resulted in a significant decrease in disease pathology. Ex vivo studies demonstrated that NKT cells from α-GalCer treated mice produced IFN-γ following α-GalCer restimulation, unlike NKT cells from vehicle-control treated mice. These data demonstrate an important role for NKT cells in the immune response to an aggressive hematologic malignancy like mantle cell lymphoma.

  18. B cells in operational tolerance.

    Science.gov (United States)

    Chesneau, M; Danger, R; Soulillou, J-P; Brouard, S

    2018-02-16

    Transplantation is currently the therapy of choice for endstage organ failure even though it requires long-term immunosuppresive therapy, with its numerous side effects, for acceptance of the transplanted organ. In rare cases however, patients develop operational tolerance, that is, graft survival without immunosuppression. Studies conducted on these patients reveal genetic, phenotypic, and functional signatures. They provide a better understanding of the immunological mechanisms involved in operational tolerance and define biomarkers that could be used to adapt immunosuppressive treatment to the individual, safely reduce immunosuppression doses, and ideally and safely guide immunosuppression withdrawal. This review summarizes studies that suggest a role for B cells as biomarkers of operational tolerance and discusses the use of B cells as a predictive tool for immunologic risk. Copyright © 2018. Published by Elsevier Inc.

  19. A versatile method to design stem-loop primer-based quantitative PCR assays for detecting small regulatory RNA molecules.

    Directory of Open Access Journals (Sweden)

    Zsolt Czimmerer

    Full Text Available Short regulatory RNA-s have been identified as key regulators of gene expression in eukaryotes. They have been involved in the regulation of both physiological and pathological processes such as embryonal development, immunoregulation and cancer. One of their relevant characteristics is their high stability, which makes them excellent candidates for use as biomarkers. Their number is constantly increasing as next generation sequencing methods reveal more and more details of their synthesis. These novel findings aim for new detection methods for the individual short regulatory RNA-s in order to be able to confirm the primary data and characterize newly identified subtypes in different biological conditions. We have developed a flexible method to design RT-qPCR assays that are very sensitive and robust. The newly designed assays were tested extensively in samples from plant, mouse and even human formalin fixed paraffin embedded tissues. Moreover, we have shown that these assays are able to quantify endogenously generated shRNA molecules. The assay design method is freely available for anyone who wishes to use a robust and flexible system for the quantitative analysis of matured regulatory RNA-s.

  20. B cells exposed to enterobacterial components suppress development of experimental colitis

    DEFF Research Database (Denmark)

    Schmidt, Esben Gjerløff Wedebye; Larsen, Hjalte List; Kristensen, Nanna Ny

    2012-01-01

    ). RESULTS: We demonstrate that splenic B cells exposed to ebx produce large amounts of IL-10 in vitro and express CD1d and CD5 previously known to be associated with regulatory B cells. In SCID mice transplanted with colitogenic CD4(+) CD25(-) T cells, co-transfer of ebx-B cells significantly suppressed...... development of colitis. Suppression was dependent on B cell-derived IL-10, as co-transfer of IL-10 knockout ebx-B cells failed to suppress colitis. Ebx-B cell-mediated suppression of colitis was associated with a decrease in interferon gamma (IFN-¿)-producing T(H) 1 cells and increased frequencies of Foxp3......-expressing T cells. CONCLUSIONS: These data demonstrate that splenic B cells exposed to enterobacterial components acquire immunosuppressive functions by which they can suppress development of experimental T cell-mediated colitis in an IL-10-dependent way. (Inflamm Bowel Dis 2011;)....

  1. Ia-restricted B-B cell interaction. I. The MHC haplotype of bone marrow cells present during B cell ontogeny dictates the self-recognition specificity of B cells in the polyclonal B cell activation by a B cell differentiation factor, B151-TRF2

    International Nuclear Information System (INIS)

    Ono, S.; Takahama, Y.; Hamaoka, T.

    1987-01-01

    We have demonstrated that B cell recognition of Ia molecules is involved in polyclonal B cell differentiation by B151-TRF2. The present study was undertaken to examine the Ia recognition specificity of B151-TRF2-responsive B cells in fully major histocompatibility complex (MHC)-allogeneic P1----P2, semiallogeneic P1----(P1 x P2)F1, and double donor (P1 + P2)----(P1 x P2)F1 and (P1 + P2)----P1 radiation bone marrow chimeras. The B cells from both P1----P2 and P1----(P1 x P2)F1 chimeras could give rise to in vitro immunoglobulin M-producing cells upon stimulation with B151-TRF2 comparable in magnitude to that of normal P1 B cells, and their responses were inhibited by anti-I-AP1 but not by anti-I-AP2 monoclonal antibody even in the presence of mitomycin C-treated T cell-depleted P2 spleen cells as auxiliary cells. In contrast, the B151-TRF2 responses of P1 B cells isolated from both (P1 + P2)----(P1 x P2)F1 and (P1 + P2)----P1 double bone marrow chimeras became sensitive to the inhibition of not only anti-I-AP1 but also anti-I-AP2 monoclonal antibody only when the culture was conducted in the presence of P2 auxiliary cells, demonstrating that they adaptively differentiate to recognize as self-structures allogeneic as well as syngeneic Ia molecules. Moreover, the experiments utilizing B cells from H-2-congenic mice and B cell hybridoma clones as auxiliary cells revealed that B151-TRF2-responsive B cells recognize Ia molecules expressed on B cells. Taken together, these results demonstrate that B151-TRF2-responsive B cells recognize Ia molecules expressed by B cells as self-structures and that their self-recognition specificity is dictated by the MHC haplotype of bone marrow cells present during the B cell ontogeny but not by the MHC haplotype of a radiation-resistant host environment

  2. Immunomodulatory effect of Mesenchymal Stem Cells on B cells

    Directory of Open Access Journals (Sweden)

    Marcella eFranquesa

    2012-07-01

    Full Text Available The research on T cell immunosuppression therapies has attracted most of the attention in clinical transplantation. However, B cells and humoral immune responses are increasingly acknowledged as crucial mediators of chronic allograft rejection. Indeed, humoral immune responses can lead to renal allograft rejection even in patients whose cell-mediated immune responses are well controlled. On the other hand, newly studied B cell subsets with regulatory effects have been linked to tolerance achievement in transplantation. Better understanding of the regulatory and effector B cell responses may therefore lead to new therapeutic approaches.Mesenchymal Stem Cells (MSC are arising as a potent therapeutic tool in transplantation due to their regenerative and immunomodulatory properties. The research on MSCs has mainly focused on their effects on T cells and although data regarding the modulatory effects of MSCs on alloantigen-specific humoral response in humans is scarce, it has been demonstrated that MSCs significantly affect B cell functioning. In the present review we will analyze and discuss the results in this field.

  3. Expression of the Grb2-related protein of the lymphoid system in B cell subsets enhances B cell antigen receptor signaling through mitogen-activated protein kinase pathways.

    Science.gov (United States)

    Yankee, Thomas M; Solow, Sasha A; Draves, Kevin D; Clark, Edward A

    2003-01-01

    Adapter proteins play a critical role in regulating signals triggered by Ag receptor cross-linking. These small molecules link receptor proximal events with downstream signaling pathways. In this study, we explore the expression and function of the Grb2-related protein of the lymphoid system (GrpL)/Grb2-related adaptor downstream of Shc adapter protein in human B cells. GrpL is expressed in naive B cells and is down-regulated following B cell Ag receptor ligation. By contrast, germinal center and memory B cells express little or no GrpL. Using human B cell lines, we detected constitutive interactions between GrpL and B cell linker protein, Src homology (SH)2 domain-containing leukocyte protein of 76 kDa, hemopoietic progenitor kinase 1, and c-Cbl. The N-terminal SH3 domain of GrpL binds c-Cbl while the C-terminal SH3 domain binds B cell linker protein and SH2 domain-containing leukocyte protein of 76 kDa. Exogenous expression of GrpL in a GrpL-negative B cell line leads to enhanced Ag receptor-induced extracellular signal-related kinase and p38 mitogen-activated protein kinase phosphorylation. Thus, GrpL expression in human B cell subsets appears to regulate Ag receptor-mediated signaling events.

  4. Differential radiosensitivity among B cell subpopulations

    International Nuclear Information System (INIS)

    Riggs, J.E.

    1988-01-01

    The selective radiosensitivity of sIgM >> sIgD marginal zone B cells is associated with the selective loss of B cell function. The simultaneous restoration of impaired function and recovery of these cells with time supports this premise. B cell recovery, delayed one week after irradiation, is in progress at two weeks, and virtually complete by three weeks. XID mice reveal similar recovery kinetics although there are fewer recovering cells and these bear reduced levels of Ia. This observation represents additional evidence that xid B cells are distinct from those of normal mice. The simultaneous loss, and concurrent recovery, of sIgM >> sIgD B cells and TI-2 responsiveness in irradiated mice suggests the existence of a unique B cell subpopulation possessing both phenotypes. Additional support for this hypothesis is provided by demonstrating that splenocytes, depleted of IgD + cells adoptively reconstitute this response in XID mice. The peritoneal B cell pool, which, compared to the spleen, consist of increased numbers of sIgM >> sIgD B cells, is shown to be a source of radiosensitive B cells that are TI-2 responsive. These observations represent additional evidence for an association between sIgM >> sIgD B cells and TI-2 responsiveness

  5. B-Cell Hematologic Malignancy Vaccination Registry

    Science.gov (United States)

    2017-12-29

    Monoclonal Gammopathy of Undetermined Significance; Multiple Myeloma; Waldenstrom Macroglobulinemia; Lymphocytosis; Lymphoma, Non-Hodgkin; B-Cell Chronic Lymphocytic Leukemia; Hematological Malignancies

  6. Surface receptor Toso controls B cell-mediated regulation of T cell immunity.

    Science.gov (United States)

    Yu, Jinbo; Duong, Vu Huy Hoang; Westphal, Katrin; Westphal, Andreas; Suwandi, Abdulhadi; Grassl, Guntram A; Brand, Korbinian; Chan, Andrew C; Föger, Niko; Lee, Kyeong-Hee

    2018-05-01

    The immune system is tightly controlled by regulatory processes that allow for the elimination of invading pathogens, while limiting immunopathological damage to the host. In the present study, we found that conditional deletion of the cell surface receptor Toso on B cells unexpectedly resulted in impaired proinflammatory T cell responses, which led to impaired immune protection in an acute viral infection model and was associated with reduced immunopathological tissue damage in a chronic inflammatory context. Toso exhibited its B cell-inherent immunoregulatory function by negatively controlling the pool of IL-10-competent B1 and B2 B cells, which were characterized by a high degree of self-reactivity and were shown to mediate immunosuppressive activity on inflammatory T cell responses in vivo. Our results indicate that Toso is involved in the differentiation/maintenance of regulatory B cells by fine-tuning B cell receptor activation thresholds. Furthermore, we showed that during influenza A-induced pulmonary inflammation, the application of Toso-specific antibodies selectively induced IL-10-competent B cells at the site of inflammation and resulted in decreased proinflammatory cytokine production by lung T cells. These findings suggest that Toso may serve as a novel therapeutic target to dampen pathogenic T cell responses via the modulation of IL-10-competent regulatory B cells.

  7. B-cell stimulating factor

    Energy Technology Data Exchange (ETDEWEB)

    Clevenger, W R; Conlon, P J; Eisenman, J R; Gillis, S; Grabstein, K H; Hopp, T P; March, C J; Mochizuki, D Y; Price, V L; Shanebeck, K D

    1987-10-05

    BSF-1 was derived from malignant cells and purified by use of various techniques, including adsorption, ion exchange chromatography and reverse phase high performance liquid chromatography. By these techniques, the BSF-1 was purified to homogenity. The high purification of the BSF-1 has made possible the sequencing of the amino acid residues at the N-terminal portion of its protein molecules. From the amino acid sequencing information, a radiolabelled oligonucleotide probe corresponding to portion of the amino acid sequence of the BSF-1 molecule was synthesized and then used to probe a cDNA library prepared from polyadenylated mRNA extracted from cell lines known to produce BSF-1. Through this procedure, a cDNA clone containing the BSF-1 gene was isolated, sequenced and mature BSF-1 expressed. The isolated cDNA clone was then radiolabelled and used as a large probe for screening cDNA libraries of other species of animals for homologous BSF-1 clones.

  8. B cells and B cell products-helping to restore cellular immunity?

    OpenAIRE

    Cascalho, Marilia; Platt, Jeffrey L.

    2006-01-01

    T cells that provide vital protection against tumors, viruses and intracellular bacteria are thought to develop independently of B cells. However, recent discoveries suggest that development of T cells depends on B cells. One way B cells promote T cell development is by providing diverse peptides that may promote positive selection of thymocytes. Diverse peptides and B cells help in diversification of the T cell receptor repertoire and may decrease cross-reactivity in the mature T cell compar...

  9. TGFβ activated kinase 1 (TAK1 at the crossroad of B cell receptor and Toll-like receptor 9 signaling pathways in human B cells.

    Directory of Open Access Journals (Sweden)

    Dániel Szili

    Full Text Available B cell development and activation are regulated by combined signals mediated by the B cell receptor (BCR, receptors for the B-cell activating factor of the tumor necrosis factor family (BAFF-R and the innate receptor, Toll-like receptor 9 (TLR9. However, the underlying mechanisms by which these signals cooperate in human B cells remain unclear. Our aim was to elucidate the key signaling molecules at the crossroads of BCR, BAFF-R and TLR9 mediated pathways and to follow the functional consequences of costimulation.Therefore we stimulated purified human B cells by combinations of anti-Ig, B-cell activating factor of the tumor necrosis factor family (BAFF and the TLR9 agonist, CpG oligodeoxynucleotide. Phosphorylation status of various signaling molecules, B cell proliferation, cytokine secretion, plasma blast generation and the frequency of IgG producing cells were investigated. We have found that BCR induced signals cooperate with BAFF-R- and TLR9-mediated signals at different levels of cell activation. BCR and BAFF- as well as TLR9 and BAFF-mediated signals cooperate at NFκB activation, while BCR and TLR9 synergistically costimulate mitogen activated protein kinases (MAPKs, ERK, JNK and p38. We show here for the first time that the MAP3K7 (TGF beta activated kinase, TAK1 is responsible for the synergistic costimulation of B cells by BCR and TLR9, resulting in an enhanced cell proliferation, plasma blast generation, cytokine and antibody production. Specific inhibitor of TAK1 as well as knocking down TAK1 by siRNA abrogates the synergistic signals. We conclude that TAK1 is a key regulator of receptor crosstalk between BCR and TLR9, thus plays a critical role in B cell development and activation.

  10. Technical Advance: New in vitro method for assaying the migration of primary B cells using an endothelial monolayer as substrate.

    Science.gov (United States)

    Stewart-Hutchinson, Phillip J; Szasz, Taylor P; Jaeger, Emily R; Onken, Michael D; Cooper, John A; Morley, Sharon Celeste

    2017-09-01

    Migration of B cells supports their development and recruitment into functional niches. Therefore, defining factors that control B cell migration will lead to a better understanding of adaptive immunity. In vitro cell migration assays with B cells have been limited by poor adhesion of cells to glass coated with adhesion molecules. We have developed a technique using monolayers of endothelial cells as the substrate for B cell migration and used this technique to establish a robust in vitro assay for B cell migration. We use TNF-α to up-regulate surface expression of the adhesion molecule VCAM-1 on endothelial cells. The ligand VLA-4 is expressed on B cells, allowing them to interact with the endothelial monolayer and migrate on its surface. We tested our new method by examining the role of L-plastin (LPL), an F-actin-bundling protein, in B cell migration. LPL-deficient (LPL -/- ) B cells displayed decreased speed and increased arrest coefficient compared with wild-type (WT) B cells, following chemokine stimulation. However, the confinement ratios for WT and LPL -/- B cells were similar. Thus, we demonstrate how the use of endothelial monolayers as a substrate will support future interrogation of molecular pathways essential to B cell migration. © Society for Leukocyte Biology.

  11. B Cell Tolerance in Health and Disease

    Directory of Open Access Journals (Sweden)

    Murali Gururajan

    2014-02-01

    Full Text Available B lymphocyte receptors are generated randomly during the bone marrow developmental phase of B cells. Hence, the B cell repertoire consists of both self and foreign antigen specificities necessitating specific tolerance mechanisms to eliminate self-reactive B cells. This review summarizes the major mechanisms of B cell tolerance, which include clonal deletion, anergy and receptor editing. In the bone marrow presentation of antigen in membrane bound form is more effective than soluble form and the role of dendritic cells in this process is discussed. Toll like receptor derived signals affect activation of B cells by certain ligands such as nucleic acids and have been shown to play crucial roles in the development of autoimmunity in several animal models. In the periphery availability of BAFF, a B cell survival factor plays a critical role in the survival of self-reactive B cells. Antibodies against BAFF have been found to be effective therapeutic agents in lupus like autoimmune diseases. Recent developments are targeting anergy to control the growth of chronic lymphocytic leukemia cells.

  12. B Cells and Autoantibodies in Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Anne-Katrin Pröbstel

    2015-07-01

    Full Text Available While over the past decades T cells have been considered key players in the pathogenesis of multiple sclerosis (MS, it has only recently become evident that B cells have a major contributing role. Our understanding of the role of B cells has evolved substantially following the clinical success of B cell-targeting therapies and increasing experimental evidence for significant B cell involvement. Rather than mere antibody-producing cells, it is becoming clear that they are team players with the capacity to prime and regulate T cells, and function both as pro- and anti-inflammatory mediators. However, despite tremendous efforts, the target antigen(s of B cells in MS have yet to be identified. The first part of this review summarizes the clinical evidence and results from animal studies pointing to the relevance of B cells in the pathogenesis of MS. The second part gives an overview of the currently known potential autoantigen targets. The third part recapitulates and critically appraises the currently available B cell-directed therapies.

  13. Splenic B cells and antigen-specific B cells process anti-Ig in a similar manner

    International Nuclear Information System (INIS)

    Myers, C.D.; Vitetta, E.S.

    1989-01-01

    B lymphocytes can process and present antigen to T cells. However, the fate of native antigen after its binding to specific B cells, i.e., the intracellular events involved in the processing and recycling of the antigenic fragments to the cell surface for antigen presentation, are not well understood. In the present study, we demonstrate that murine B cells degrade anti-Ig molecules bound to their surface and release acid soluble fragments into the supernatant. We also demonstrate that the kinetics of this process are identical for anti-mu, anti-delta, and anti-light chain antibodies, indicating that both surface IgM and surface IgD are equally effective in binding antigen and directing its processing. We also describe the effects of azide, chloroquine, and irradiation on this process. To extend these studies to the processing of specifically bound antigen, we demonstrate that highly purified trinitrophenyl antigen-binding cells degrade anti-Ig molecules with the same kinetics as unpurified splenic B cells. Thus, this purified population provides a suitable model system for the analysis of antigen degradation by antigen-specific cells

  14. Ikaros limits follicular B cell activation by regulating B cell receptor signaling pathways

    International Nuclear Information System (INIS)

    Heizmann, Beate; Sellars, MacLean; Macias-Garcia, Alejandra; Chan, Susan; Kastner, Philippe

    2016-01-01

    The Ikaros transcription factor is essential for early B cell development, but its effect on mature B cells is debated. We show that Ikaros is required to limit the response of naive splenic B cells to B cell receptor signals. Ikaros deficient follicular B cells grow larger and enter cell cycle faster after anti-IgM stimulation. Unstimulated mutant B cells show deregulation of positive and negative regulators of signal transduction at the mRNA level, and constitutive phosphorylation of ERK, p38, SYK, BTK, AKT and LYN. Stimulation results in enhanced and prolonged ERK and p38 phosphorylation, followed by hyper-proliferation. Pharmacological inhibition of ERK and p38 abrogates the increased proliferative response of Ikaros deficient cells. These results suggest that Ikaros functions as a negative regulator of follicular B cell activation.

  15. Ikaros limits follicular B cell activation by regulating B cell receptor signaling pathways

    Energy Technology Data Exchange (ETDEWEB)

    Heizmann, Beate [Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch (France); Sellars, MacLean [Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch (France); David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Macias-Garcia, Alejandra [Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch (France); Institute for Medical Engineering and Science at MIT, Cambridge, MA 02139 (United States); Chan, Susan, E-mail: scpk@igbmc.fr [Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch (France); Kastner, Philippe, E-mail: scpk@igbmc.fr [Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch (France); Faculté de Médecine, Université de Strasbourg, Strasbourg (France)

    2016-02-12

    The Ikaros transcription factor is essential for early B cell development, but its effect on mature B cells is debated. We show that Ikaros is required to limit the response of naive splenic B cells to B cell receptor signals. Ikaros deficient follicular B cells grow larger and enter cell cycle faster after anti-IgM stimulation. Unstimulated mutant B cells show deregulation of positive and negative regulators of signal transduction at the mRNA level, and constitutive phosphorylation of ERK, p38, SYK, BTK, AKT and LYN. Stimulation results in enhanced and prolonged ERK and p38 phosphorylation, followed by hyper-proliferation. Pharmacological inhibition of ERK and p38 abrogates the increased proliferative response of Ikaros deficient cells. These results suggest that Ikaros functions as a negative regulator of follicular B cell activation.

  16. The nanoscale spatial organization of B-cell receptors on immunoglobulin M- and G-expressing human B-cells.

    Science.gov (United States)

    Lee, Jinmin; Sengupta, Prabuddha; Brzostowski, Joseph; Lippincott-Schwartz, Jennifer; Pierce, Susan K

    2017-02-15

    B-cell activation is initiated by the binding of antigen to the B-cell receptor (BCR). Here we used dSTORM superresolution imaging to characterize the nanoscale spatial organization of immunoglobulin M (IgM) and IgG BCRs on the surfaces of resting and antigen--activated human peripheral blood B-cells. We provide insights into both the fundamental process of antigen-driven BCR clustering and differences in the spatial organization of IgM and IgG BCRs that may contribute to the characteristic differences in the responses of naive and memory B-cells to antigen. We provide evidence that although both IgM and IgG BCRs reside in highly heterogeneous protein islands that vary in size and number of BCR single-molecule localizations, both resting and activated B-cells intrinsically maintain a high -frequency of single isolated BCR localizations, which likely represent BCR monomers. IgG BCRs are more clustered than IgM BCRs on resting cells and form larger protein islands after antigen activation. Small, dense BCR clusters likely formed via protein-protein interactions are present on the surface of resting cells, and antigen activation induces these to come together to form less dense, larger islands, a process likely governed, at least in part, by protein-lipid interactions. © 2017 Lee, Sengupta, et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  17. B cell subset distribution is altered in patients with severe periodontitis.

    Science.gov (United States)

    Demoersman, Julien; Pochard, Pierre; Framery, Camille; Simon, Quentin; Boisramé, Sylvie; Soueidan, Assem; Pers, Jacques-Olivier

    2018-01-01

    Several studies have recently highlighted the implication of B cells in physiopathogenesis of periodontal disease by showing that a B cell deficiency leads to improved periodontal parameters. However, the detailed profiles of circulating B cell subsets have not yet been investigated in patients with severe periodontitis (SP). We hypothesised that an abnormal distribution of B cell subsets could be detected in the blood of patients with severe periodontal lesions, as already reported for patients with chronic inflammatory diseases as systemic autoimmune diseases. Fifteen subjects with SP and 13 subjects without periodontitis, according to the definition proposed by the CDC periodontal disease surveillance work group, were enrolled in this pilot observational study. Two flow cytometry panels were designed to analyse the circulating B and B1 cell subset distribution in association with the RANKL expression. A significantly higher percentage of CD27+ memory B cells was observed in patients with SP. Among these CD27+ B cells, the proportion of the switched memory subset was significantly higher. At the same time, human B1 cells, which were previously associated with a regulatory function (CD20+CD69-CD43+CD27+CD11b+), decreased in SP patients. The RANKL expression increased in every B cell subset from the SP patients and was significantly greater in activated B cells than in the subjects without periodontitis. These preliminary results demonstrate the altered distribution of B cells in the context of severe periodontitis. Further investigations with a larger cohort of patients can elucidate if the analysis of the B cell compartment distribution can reflect the periodontal disease activity and be a reliable marker for its prognosis (clinical trial registration number: NCT02833285, B cell functions in periodontitis).

  18. B cell subset distribution is altered in patients with severe periodontitis

    Science.gov (United States)

    Demoersman, Julien; Pochard, Pierre; Framery, Camille; Simon, Quentin; Boisramé, Sylvie; Soueidan, Assem

    2018-01-01

    Several studies have recently highlighted the implication of B cells in physiopathogenesis of periodontal disease by showing that a B cell deficiency leads to improved periodontal parameters. However, the detailed profiles of circulating B cell subsets have not yet been investigated in patients with severe periodontitis (SP). We hypothesised that an abnormal distribution of B cell subsets could be detected in the blood of patients with severe periodontal lesions, as already reported for patients with chronic inflammatory diseases as systemic autoimmune diseases. Fifteen subjects with SP and 13 subjects without periodontitis, according to the definition proposed by the CDC periodontal disease surveillance work group, were enrolled in this pilot observational study. Two flow cytometry panels were designed to analyse the circulating B and B1 cell subset distribution in association with the RANKL expression. A significantly higher percentage of CD27+ memory B cells was observed in patients with SP. Among these CD27+ B cells, the proportion of the switched memory subset was significantly higher. At the same time, human B1 cells, which were previously associated with a regulatory function (CD20+CD69-CD43+CD27+CD11b+), decreased in SP patients. The RANKL expression increased in every B cell subset from the SP patients and was significantly greater in activated B cells than in the subjects without periodontitis. These preliminary results demonstrate the altered distribution of B cells in the context of severe periodontitis. Further investigations with a larger cohort of patients can elucidate if the analysis of the B cell compartment distribution can reflect the periodontal disease activity and be a reliable marker for its prognosis (clinical trial registration number: NCT02833285, B cell functions in periodontitis). PMID:29447240

  19. B-cell waste classification sampling plan

    International Nuclear Information System (INIS)

    HOBART, R.L.

    1999-01-01

    This report documents the methods used to collect samples and analyze data necessary to verify and/or determine the radionuclide content of the 324 Facility B-Cell decontamination and decommissioning waste stream

  20. B cell remote-handled waste shipment cask alternatives study

    International Nuclear Information System (INIS)

    RIDDELLE, J.G.

    1999-01-01

    The decommissioning of the 324 Facility B Cell includes the onsite transport of grouted remote-handled radioactive waste from the 324 Facility to the 200 Areas for disposal. The grouted waste has been transported in the leased ATG Nuclear Services 3-82B Radioactive Waste Shipping Cask (3-82B cask). Because the 3-82B cask is a U.S. Nuclear Regulatory Commission (NRC)-certified Type B shipping cask, the lease cost is high, and the cask operations in the onsite environment may not be optimal. An alternatives study has been performed to develop cost and schedule information on alternative waste transportation systems to assist in determining which system should be used in the future. Five alternatives were identified for evaluation. These included continued lease of the 3-82B cask, fabrication of a new 3-82B cask, development and fabrication of an onsite cask, modification of the existing U.S. Department of Energy-owned cask (OH-142), and the lease of a different commercially available cask. Each alternative was compared to acceptance criteria for use in the B Cell as an initial screening. Only continued leasing of the 3-82B cask, fabrication of a new 3-82B cask, and the development and fabrication of an onsite cask were found to meet all of the B Cell acceptance criteria

  1. Metabolic activity is necessary for activation of T suppressor cells by B cells

    International Nuclear Information System (INIS)

    Elkins, K.L.; Stashak, P.W.; Baker, P.J.

    1990-01-01

    Ag-primed B cells must express cell-surface IgM, but not IgD or Ia Ag, and must remain metabolically active, in order to activate suppressor T cells (Ts) specific for type III pneumococcal polysaccharide. Ag-primed B cells that were gamma-irradiated with 1000r, or less, retained the ability to activate Ts; however, Ag-primed B cells exposed to UV light were not able to do so. gamma-Irradiated and UV-treated Ag-primed B cells both expressed comparable levels of cell-surface IgM, and both localized to the spleen after in vivo transfer; neither could proliferate in vitro in response to mitogens. By contrast, gamma-irradiated primed B cells were still able to synthesize proteins, whereas UV-treated primed B cells could not. These findings suggest that in order for Ag-primed B cells to activate Ts, they must (a) express cell-associated IgM (sIgM) antibody bearing the idiotypic determinants of antibody specific for type III pneumococcal polysaccharide, and (b) be able to synthesize protein for either the continued expression of sIgM after cell transfer, or for the elaboration of another protein molecule that is also required for the activation of Ts; this molecule does not appear to be Ia Ag

  2. Memory control by the B cell antigen receptor.

    Science.gov (United States)

    Engels, Niklas; Wienands, Jürgen

    2018-05-01

    The generation of memory B cells (MBCs) that have undergone immunoglobulin class switching from IgM, which dominates primary antibody responses, to other immunoglobulin isoforms is a hallmark of immune memory. Hence, humoral immunological memory is characterized by the presence of serum immunoglobulins of IgG subtypes known as the γ-globulin fraction of blood plasma proteins. These antibodies reflect the antigen experience of B lymphocytes and their repeated triggering. In fact, efficient protection against a previously encountered pathogen is critically linked to the production of pathogen-specific IgG molecules even in those cases where the primary immune response required cellular immunity, for example, T cell-mediated clearance of intracellular pathogens such as viruses. Besides IgG, also IgA and IgE can provide humoral immunity depending on the microbe's nature and infection route. The molecular mechanisms underlying the preponderance of switched immunoglobulin isotypes during memory antibody responses are a matter of active and controversial debate. Here, we summarize the phenotypic characteristics of distinct MBC subpopulations and discuss the decisive roles of different B cell antigen receptor isotypes for the functional traits of class-switched B cell populations. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Dynamic EBF1 occupancy directs sequential epigenetic and transcriptional events in B-cell programming.

    Science.gov (United States)

    Li, Rui; Cauchy, Pierre; Ramamoorthy, Senthilkumar; Boller, Sören; Chavez, Lukas; Grosschedl, Rudolf

    2018-01-15

    B-cell fate determination requires the action of transcription factors that operate in a regulatory network to activate B-lineage genes and repress lineage-inappropriate genes. However, the dynamics and hierarchy of events in B-cell programming remain obscure. To uncouple the dynamics of transcription factor expression from functional consequences, we generated induction systems in developmentally arrested Ebf1 -/- pre-pro-B cells to allow precise experimental control of EBF1 expression in the genomic context of progenitor cells. Consistent with the described role of EBF1 as a pioneer transcription factor, we show in a time-resolved analysis that EBF1 occupancy coincides with EBF1 expression and precedes the formation of chromatin accessibility. We observed dynamic patterns of EBF1 target gene expression and sequential up-regulation of transcription factors that expand the regulatory network at the pro-B-cell stage. A continuous EBF1 function was found to be required for Cd79a promoter activity and for the maintenance of an accessible chromatin domain that is permissive for binding of other transcription factors. Notably, transient EBF1 occupancy was detected at lineage-inappropriate genes prior to their silencing in pro-B cells. Thus, persistent and transient functions of EBF1 allow for an ordered sequence of epigenetic and transcriptional events in B-cell programming. © 2018 Li et al.; Published by Cold Spring Harbor Laboratory Press.

  4. Bone marrow pre-B cells and the clonal anergy theory of immunologic tolerance.

    Science.gov (United States)

    Nossal, G J

    1987-03-01

    This review begins with a summary of a decade's research from the author's own laboratory which documents the fact that B lymphocytes can receive and store negative, down-regulatory signals from an encounter with antigen, and that the sensitivity to such negative signalling depends critically on maturational status, the most immature B cells being the most susceptible. The review then examines the relationship between these experimentally-induced models of immunologic tolerance, with the pre-B to B cell transition as the critical stage for examination, and the real-life phenomenon of self-tolerance. It makes the point that no repertoire-purging mechanism to ensure self-tolerance can afford to be too effective, for fear of purging too many useful cells, given the number and variability of self-antigens. The review then examines certain dilemmas posed by recent findings in cellular and molecular immunology. These include: 1) the preferential use of particular VH gene families by B cells at different stages of the differentiation process; 2) the apparent frequency of B lymphocytes with the potential for antiself-reactivity in the B cell repertoire; and 3) the existence of a new type of B cell, the Ly-1-positive B cell, with peculiar characteristics. These findings are considered within the particular contexts of pre-B-to-B cell transition and tolerance induction through clonal anergy mechanisms.

  5. PU.1 cooperates with IRF4 and IRF8 to suppress pre-B cell leukemia

    Science.gov (United States)

    Pang, Swee Heng Milon; Minnich, Martina; Gangatirkar, Pradnya; Zheng, Zhiqiang; Ebert, Anja; Song, Guangchun; Dickins, Ross A; Corcoran, Lynn M; Mullighan, Charles G.; Busslinger, Meinrad; Huntington, Nicholas D; Nutt, Stephen L; Carotta, Sebastian

    2016-01-01

    The Ets family transcription factor PU.1 and the interferon regulatory factor (IRF)4 and IRF8 regulate gene expression by binding to composite DNA sequences known as Ets/interferon consensus elements (EICE). Although all three factors are expressed from the onset of B cell development, single deficiency of these factors in B cell progenitors only mildly impacts on bone marrow B-lymphopoiesis. Here we tested whether PU.1 cooperates with IRF factors in regulating early B cell development. Lack of PU.1 and IRF4 resulted in a partial block in development the pre-B cell stage. The combined deletion of PU.1 and IRF8 reduced recirculating B cell numbers. Strikingly, all PU.1/IRF4 and approximately 50% of PU.1/IRF8 double deficient mice developed pre-B cell acute lymphoblastic leukemia (B-ALL) associated with reduced expression of the established B-lineage tumor suppressor genes, Ikaros and Spi-B. These genes are directly regulated by PU.1/IRF4/IRF8, and restoration of Ikaros or Spi-B expression inhibited leukemic cell growth. In summary, we demonstrate that PU.1, IRF4 and IRF8 cooperate to regulate early B cell development and to prevent pre-B-ALL formation. PMID:26932576

  6. Unconventional Pro-inflammatory CD4+ T Cell Response in B Cell-Deficient Mice Infected with Trypanosoma cruzi

    Directory of Open Access Journals (Sweden)

    Melisa Gorosito Serrán

    2017-11-01

    Full Text Available Chagas disease, caused by the parasite Trypanosoma cruzi, is endemic in Latin America but has become a global public health concern by migration of infected people. It has been reported that parasite persistence as well as the intensity of the inflammatory immune response are determinants of the clinical manifestations of the disease. Even though inflammation is indispensable for host defense, when deregulated, it can contribute to tissue injury and organ dysfunction. Here, we report the importance of B cells in conditioning T cell response in T. cruzi infection. Mice deficient in mature B cells (muMT mice infected with T. cruzi exhibited an increase in plasma TNF concentration, TNF-producing CD4+ T cells, and mortality. The increase in TNF-producing CD4+ T cells was accompanied by a reduction in IFNγ+CD4+ T cells and a decrease of the frequency of regulatory Foxp3+, IL-10+, and IL17+CD4+ T cells populations. The CD4+ T cell population activated by T. cruzi infection, in absence of mature B cells, had a high frequency of Ly6C+ cells and showed a lower expression of inhibitory molecules such as CTLA-4, PD-1, and LAG3. CD4+ T cells from infected muMT mice presented a high frequency of CD62LhiCD44− cells, which is commonly associated with a naïve phenotype. Through transfer experiments we demonstrated that CD4+ T cells from infected muMT mice were able to condition the CD4+ T cells response from infected wild-type mice. Interestingly, using Blimp-flox/flox-CD23icre mice we observed that in absence of plasmablast/plasma cell T. cruzi-infected mice exhibited a higher number of TNF-producing CD4+ T cells. Our results showed that the absence of B cells during T. cruzi infection affected the T cell response at different levels and generated a favorable scenario for unconventional activation of CD4+ T cell leading to an uncontrolled effector response and inflammation. The product of B cell differentiation, the plasmablast/plasma cells, could be able

  7. Double-hit B-cell lymphomas

    NARCIS (Netherlands)

    Aukema, Sietse M.; Siebert, Reiner; Schuuring, Ed; van Imhoff, Gustaaf W.; Kluin-Nelemans, Hanneke C.; Boerma, Evert-Jan; Kluin, Philip M.

    2011-01-01

    In many B-cell lymphomas, chromosomal translocations are biologic and diagnostic hallmarks of disease. An intriguing subset is formed by the so-called double-hit (DH) lymphomas that are defined by a chromosomal breakpoint affecting the MYC/8q24 locus in combination with another recurrent breakpoint,

  8. A Versatile Method to Design Stem-Loop Primer-Based Quantitative PCR Assays for Detecting Small Regulatory RNA Molecules

    OpenAIRE

    Czimmerer, Zsolt; Hulvely, Julianna; Simandi, Zoltan; Varallyay, Eva; Havelda, Zoltan; Szabo, Erzsebet; Varga, Attila; Dezso, Balazs; Balogh, Maria; Horvath, Attila; Domokos, Balint; Torok, Zsolt; Nagy, Laszlo; Balint, Balint L.

    2013-01-01

    Short regulatory RNA-s have been identified as key regulators of gene expression in eukaryotes. They have been involved in the regulation of both physiological and pathological processes such as embryonal development, immunoregulation and cancer. One of their relevant characteristics is their high stability, which makes them excellent candidates for use as biomarkers. Their number is constantly increasing as next generation sequencing methods reveal more and more details of their synthesis. T...

  9. Altered Distribution of Peripheral Blood Maturation-Associated B-Cell Subsets in Chronic Alcoholism.

    Science.gov (United States)

    Almeida, Julia; Polvorosa, Maria Angeles; Gonzalez-Quintela, Arturo; Madruga, Ignacio; Marcos, Miguel; Pérez-Nieto, Maria Angeles; Hernandez-Cerceño, Maria Luisa; Orfao, Alberto; Laso, Francisco Javier

    2015-08-01

    Although decreased counts of peripheral blood (PB) B cells-associated with an apparently contradictory polyclonal hypergammaglobulinemia-have been reported in chronic alcoholism, no information exists about the specific subsets of circulating B cells altered and their relationship with antibody production. Here, we analyzed for the first time the distribution of multiple maturation-associated subpopulations of PB B cells in alcoholism and its potential relationship with the onset of liver disease. PB samples from 35 male patients-20 had alcoholic hepatitis (AH) and 15 chronic alcoholism without liver disease (AWLD)-were studied, in parallel to 19 male healthy donors (controls). The distribution of PB B-cell subsets (immature/regulatory, naïve, CD27(-) and CD27(+) memory B lymphocytes, and circulating plasmablasts of distinct immunoglobulin-Ig-isotypes) was analyzed by flow cytometry. Patients with AH showed significantly decreased numbers of total PB B lymphocytes (vs. controls and AWLD), at the expense of immature, memory, and, to a lesser extent, also naïve B cells. AWLD showed reduced numbers of immature and naïve B cells (vs. controls), but higher PB counts of plasmablasts (vs. the other 2 groups). Although PB memory B cells were reduced among the patients, the percentage of surface (s)IgA(+) cells (particularly CD27(-) /sIgA(+) cells) was increased in AH, whereas both sIgG(+) and sIgA(+) memory B cells were significantly overrepresented in AWLD versus healthy donors. Regarding circulating plasmablasts, patients with AH only showed significantly reduced counts of sIgG(+) cells versus controls. In contrast, the proportion of both sIgA(+) and sIgG(+) plasmablasts-from all plasmablasts-was reduced in AH and increased in AWLD (vs. the other 2 groups). AH and AWLD patients display a significantly reduced PB B-cell count, at the expense of decreased numbers of recently produced immature/regulatory B cells and naïve B cells, together with an increase in Ig

  10. IL-10-produced by human transitional B-cells down-regulates CD86 expression on B-cells leading to inhibition of CD4+T-cell responses.

    Science.gov (United States)

    Nova-Lamperti, Estefania; Fanelli, Giorgia; Becker, Pablo D; Chana, Prabhjoat; Elgueta, Raul; Dodd, Philippa C; Lord, Graham M; Lombardi, Giovanna; Hernandez-Fuentes, Maria P

    2016-01-22

    A novel subset of human regulatory B-cells has recently been described. They arise from within the transitional B-cell subpopulation and are characterised by the production of IL-10. They appear to be of significant importance in regulating T-cell immunity in vivo. Despite this important function, the molecular mechanisms by which they control T-cell activation are incompletely defined. Here we show that transitional B-cells produced more IL-10 and expressed higher levels of IL-10 receptor after CD40 engagement compared to other B-cell subsets. Furthermore, under this stimulatory condition, CD86 expressed by transitional B-cells was down regulated and T-cell proliferation was reduced. We provide evidence to demonstrate that the down-regulation of CD86 expression by transitional B-cells was due to the autocrine effect of IL-10, which in turn leads to decreased T-cell proliferation and TNF-α production. This analysis was further extended to peripheral B-cells in kidney transplant recipients. We observed that B-cells from patients tolerant to the graft maintained higher IL-10 production after CD40 ligation, which correlates with lower CD86 expression compared to patients with chronic rejection. Hence, the results obtained in this study shed light on a new alternative mechanism by which transitional B-cells inhibit T-cell proliferation and cytokine production.

  11. IL-10-produced by human transitional B-cells down-regulates CD86 expression on B-cells leading to inhibition of CD4+T-cell responses

    Science.gov (United States)

    Nova-Lamperti, Estefania; Fanelli, Giorgia; Becker, Pablo D.; Chana, Prabhjoat; Elgueta, Raul; Dodd, Philippa C.; Lord, Graham M.; Lombardi, Giovanna; Hernandez-Fuentes, Maria P.

    2016-01-01

    A novel subset of human regulatory B-cells has recently been described. They arise from within the transitional B-cell subpopulation and are characterised by the production of IL-10. They appear to be of significant importance in regulating T-cell immunity in vivo. Despite this important function, the molecular mechanisms by which they control T-cell activation are incompletely defined. Here we show that transitional B-cells produced more IL-10 and expressed higher levels of IL-10 receptor after CD40 engagement compared to other B-cell subsets. Furthermore, under this stimulatory condition, CD86 expressed by transitional B-cells was down regulated and T-cell proliferation was reduced. We provide evidence to demonstrate that the down-regulation of CD86 expression by transitional B-cells was due to the autocrine effect of IL-10, which in turn leads to decreased T-cell proliferation and TNF-α production. This analysis was further extended to peripheral B-cells in kidney transplant recipients. We observed that B-cells from patients tolerant to the graft maintained higher IL-10 production after CD40 ligation, which correlates with lower CD86 expression compared to patients with chronic rejection. Hence, the results obtained in this study shed light on a new alternative mechanism by which transitional B-cells inhibit T-cell proliferation and cytokine production. PMID:26795594

  12. Analysis of Peripheral B Cell Subsets in Patients With Allergic Rhinitis.

    Science.gov (United States)

    Luo, Jing; Guo, Huanhuan; Liu, Zhuofu; Peng, Tao; Hu, Xianting; Han, Miaomiao; Yang, Xiangping; Zhou, Xuhong; Li, Huabin

    2018-05-01

    Recent evidence suggests that B cells can both promote and inhibit the development and progression of allergic disease. However, the characteristics of B cell subsets in patients with allergic rhinitis (AR) have not been well documented. This study aimed to analyze the characteristics of B cell subsets in the peripheral blood of AR patients. Forty-seven AR patients and 54 healthy controls were enrolled in this study, and the B cell subsets in peripheral blood of all subjects were analyzed by flow cytometry. Moreover, the serum total immunoglobulin E (IgE) and IgE concentrations secreted into the cultured peripheral blood mononuclear cells (PBMCs) were measured by using enzyme-linked immunosorbent assay. We found the peripheral blood of AR patients contained higher percentages of memory B cells, plasma cells, and CD19⁺CD24(hi)CD27⁺ regulatory B cells (Bregs) than those of age-matched healthy controls (PB cells and CD19⁺CD24(hi)CD38(hi) Bregs were significantly lower in AR patients than in healthy individuals (PB cells or plasma cells and decreases in CD19⁺CD24(hi)CD38(hi) Breg cells in the peripheral blood. Copyright © 2018 The Korean Academy of Asthma, Allergy and Clinical Immunology · The Korean Academy of Pediatric Allergy and Respiratory Disease.

  13. Rituximab does not reset defective early B cell tolerance checkpoints

    Science.gov (United States)

    Chamberlain, Nicolas; Massad, Christopher; Oe, Tyler; Cantaert, Tineke; Herold, Kevan C.; Meffre, Eric

    2015-01-01

    Type 1 diabetes (T1D) patients show abnormalities in early B cell tolerance checkpoints, resulting in the accumulation of large numbers of autoreactive B cells in their blood. Treatment with rituximab, an anti-CD20 mAb that depletes B cells, has been shown to preserve β cell function in T1D patients and improve other autoimmune diseases, including rheumatoid arthritis and multiple sclerosis. However, it remains largely unknown how anti–B cell therapy thwarts autoimmunity in these pathologies. Here, we analyzed the reactivity of Abs expressed by single, mature naive B cells from 4 patients with T1D before and 52 weeks after treatment to determine whether rituximab resets early B cell tolerance checkpoints. We found that anti–B cell therapy did not alter the frequencies of autoreactive and polyreactive B cells, which remained elevated in the blood of all patients after rituximab treatment. Moreover, the limited proliferative history of autoreactive B cells after treatment revealed that these clones were newly generated B cells and not self-reactive B cells that had escaped depletion and repopulated the periphery through homeostatic expansion. We conclude that anti–B cell therapy may provide a temporary dampening of autoimmune processes through B cell depletion. However, repletion with autoreactive B cells may explain the relapse that occurs in many autoimmune patients after anti–B cell therapy. PMID:26642366

  14. High-dose bee venom exposure induces similar tolerogenic B-cell responses in allergic patients and healthy beekeepers.

    Science.gov (United States)

    Boonpiyathad, T; Meyer, N; Moniuszko, M; Sokolowska, M; Eljaszewicz, A; Wirz, O F; Tomasiak-Lozowska, M M; Bodzenta-Lukaszyk, A; Ruxrungtham, K; van de Veen, W

    2017-03-01

    The involvement of B cells in allergen tolerance induction remains largely unexplored. This study investigates the role of B cells in this process, by comparing B-cell responses in allergic patients before and during allergen immunotherapy (AIT) and naturally exposed healthy beekeepers before and during the beekeeping season. Circulating B cells were characterized by flow cytometry. Phospholipase A2 (PLA)-specific B cells were identified using dual-color staining with fluorescently labeled PLA. Expression of regulatory B-cell-associated surface markers, interleukin-10, chemokine receptors, and immunoglobulin heavy-chain isotypes, was measured. Specific and total IgG1, IgG4, IgA, and IgE from plasma as well as culture supernatants of PLA-specific cells were measured by ELISA. Strikingly, similar responses were observed in allergic patients and beekeepers after venom exposure. Both groups showed increased frequencies of plasmablasts, PLA-specific memory B cells, and IL-10-secreting CD73 - CD25 + CD71 + B R 1 cells. Phospholipase A2-specific IgG4-switched memory B cells expanded after bee venom exposure. Interestingly, PLA-specific B cells showed increased CCR5 expression after high-dose allergen exposure while CXCR4, CXCR5, CCR6, and CCR7 expression remained unaffected. This study provides the first detailed characterization of allergen-specific B cells before and after bee venom tolerance induction. The observed B-cell responses in both venom immunotherapy-treated patients and naturally exposed beekeepers suggest a similar functional immunoregulatory role for B cells in allergen tolerance in both groups. These findings can be investigated in other AIT models to determine their potential as biomarkers of early and successful AIT responses. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Interaction of the B cell-specific transcriptional coactivator OCA-B and galectin-1 and a possible role in regulating BCR-mediated B cell proliferation.

    Science.gov (United States)

    Yu, Xin; Siegel, Rachael; Roeder, Robert G

    2006-06-02

    OCA-B is a B cell-specific transcriptional coactivator for OCT factors during the activation of immunoglobulin genes. In addition, OCA-B is crucial for B cell activation and germinal center formation. However, the molecular mechanisms for OCA-B function in these processes are not clear. Our previous studies documented two OCA-B isoforms and suggested a novel mechanism for the function of the myristoylated, membrane-bound form of OCA-B/p35 as a signaling molecule. Here, we report the identification of galectin-1, and related galectins, as a novel OCA-B-interacting protein. The interaction of OCA-B and galectin-1 can be detected both in vivo and in vitro. The galectin-1 binding domain in OCA-B has been localized to the N terminus of OCA-B. In B cells lacking OCA-B expression, increased galectin-1 expression, secretion, and cell surface association are observed. Consistent with these observations, and a reported inhibitory interaction of galectin-1 with CD45, the phosphatase activity of CD45 is reduced modestly, but significantly, in OCA-B-deficient B cells. Finally, galectin-1 is shown to negatively regulate B cell proliferation and tyrosine phosphorylation upon BCR stimulation. Together, these results raise the possibility that OCA-B may regulate BCR signaling through an association with galectin-1.

  16. Primary Hepatosplenic Large B-Cell Lymphoma

    Directory of Open Access Journals (Sweden)

    M.R. Morales-Polanco

    2008-03-01

    Full Text Available Diffuse large B-cell lymphoma is the most common form of lymphoma. It usually begins in the lymph nodes; up to 40% may have an extranodal presentation. According to a definition of primary extranodal lymphoma with presentation only in extranodal sites, there are reports of large B-cell lymphomas limited to liver or spleen as separate entities, and to date there have been only three documented cases of primary hepatosplenic presentation. This paper reports a fourth case. Due to a review of the literature and the clinical course of the case reported, we conclude that primary hepatosplenic large B-cell lymphoma has been found predominantly in females older than 60 years. The patients reported had <2 months of evolution prior to diagnosis, prominent B symptoms, splenomegaly in three and hepatomegaly in two, none with lymph node involvement. All had thrombocytopenia and abnormal liver function tests; three had anemia and elevated serum lactic dehydrogenase levels, two with hemophagocytosis in bone marrow. Because of the previously mentioned data, it can be stated that primary hepatosplenic lymphoma is an uncommon and aggressive form of disease that requires immediate recognition and treatment.

  17. JSI-124 inhibits IgE production in an IgE B cell line

    International Nuclear Information System (INIS)

    Cui, Lulu; Bi, Jiacheng; Yan, Dehong; Ye, Xiufeng; Zheng, Mingxing; Yu, Guang; Wan, Xiaochun

    2017-01-01

    IgE is a key effector molecule in atopic diseases; however, the regulation mechanisms of IgE production in IgE B cells remain poorly understood. In the present study, we demonstrate that JSI-124 (cucurbitacin I), a selective STAT3 inhibitor, selectively inhibits production of IgE by a human IgE B cell line, CRL-8033 cells, while does not affect the IgG production by IgG B cell lines. In the aspect of molecular mechanism, we found that Igλ, but not Ighe, gene expression was suppressed by JSI-124. The above effects of JSI-124 were not mediated by affecting cellular proliferation or apoptosis. Furthermore, multiple B cell differentiation-related genes expression was not significantly affected by JSI-124. Taken together, we demonstrate a potential strategy of therapeutically suppressing IgE production without affecting IgG production in atopic patients. - Highlights: • JSI-124 inhibits IgE production in an IgE B cell line, CRL-8033 cells. • JSI-124 does not affect IgG production by IgG B cell lines. • JSI-124 inhibits IgE production mainly by suppressing transcription of Igλ.

  18. B cell receptor inhibition as a target for CLL therapy.

    Science.gov (United States)

    Jeyakumar, Deepa; O'Brien, Susan

    2016-03-01

    Inhibitors of the B cell receptor (BCR) represent an attractive therapeutic option for patients with chronic lymphocytic leukemia. Recently approved inhibitors of Bruton's tyrosine kinase (ibrutinib) and phosphatidylinositol 3-kinase (idelalisib), are promising agents because they are generally well tolerated and highly effective. These agents may be particularly important in the treatment of older patients who are less able to tolerate the myelosuppression (and infections) associated with chemoimmunotherapy. As a class of medications, BCR inhibitors have some unique side effects including redistribution lymphocytosis. Ibrutinib has specific toxicities including increased risk for bleeding and atrial fibrillation. Idelalisib also has some unique toxicities consisting of transaminitis, diarrhea and pneumonitis. Ongoing clinical trials are evaluating these agents in combination with antibodies, chemotherapy and other small molecules. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. In Silico Prediction Analysis of Idiotope-Driven T–B Cell Collaboration in Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Rune A. Høglund

    2017-10-01

    Full Text Available Memory B cells acting as antigen-presenting cells are believed to be important in multiple sclerosis (MS, but the antigen they present remains unknown. We hypothesized that B cells may activate CD4+ T cells in the central nervous system of MS patients by presenting idiotopes from their own immunoglobulin variable regions on human leukocyte antigen (HLA class II molecules. Here, we use bioinformatics prediction analysis of B cell immunoglobulin variable regions from 11 MS patients and 6 controls with other inflammatory neurological disorders (OINDs, to assess whether the prerequisites for such idiotope-driven T–B cell collaboration are present. Our findings indicate that idiotopes from the complementarity determining region (CDR 3 of MS patients on average have high predicted affinities for disease associated HLA-DRB1*15:01 molecules and are predicted to be endosomally processed by cathepsin S and L in positions that allows such HLA binding to occur. Additionally, complementarity determining region 3 sequences from cerebrospinal fluid (CSF B cells from MS patients contain on average more rare T cell-exposed motifs that could potentially escape tolerance and stimulate CD4+ T cells than CSF B cells from OIND patients. Many of these features were associated with preferential use of the IGHV4 gene family by CSF B cells from MS patients. This is the first study to combine high-throughput sequencing of patient immune repertoires with large-scale prediction analysis and provides key indicators for future in vitro and in vivo analyses.

  20. The double bromodomain protein Brd2 promotes B cell expansion and mitogenesis.

    Science.gov (United States)

    Belkina, Anna C; Blanton, Wanda P; Nikolajczyk, Barbara S; Denis, Gerald V

    2014-03-01

    Bromodomain-containing transcriptional regulators represent new epigenetic targets in different hematologic malignancies. However, bromodomain-mediated mechanisms that couple histone acetylation to transcription in lymphopoiesis and govern mature lymphocyte mitogenesis are poorly understood. Brd2, a transcriptional coregulator that contains dual bromodomains and an extraterminal domain (the BET family), couples chromatin to cell-cycle progression. We reported previously the first functional characterization of a BET protein as an effector of mammalian mitogenic signal transduction: Eμ-Brd2 Tg mice develop "activated B cell" diffuse large B cell lymphoma. No other animal models exist for genetic or lentiviral expression of BET proteins, hampering testing of novel anti-BET anticancer drugs, such as JQ1. We transduced HSCs with Brd2 lentivirus and reconstituted recipient mice to test the hypothesis that Brd2 regulates hematopoiesis in BM and mitogenesis in the periphery. Forced expression of Brd2 provides an expansion advantage to the donor-derived B cell compartment in BM and increases mature B cell mitogenic responsiveness in vitro. Brd2 binds the cyclin A promoter in B cells, shown by ChIP, and increases cyclin A mRNA and protein levels, and S-phase progression in vitro in mitogen-stimulated primary B cells, but not T cells, reinforcing results from Eμ-Brd2 mice. The small molecule BET inhibitor JQ1 reduces B cell mitogenesis, consistent with the interpretation that BET inhibitors are antiproliferative. Brd2-specific knockdown experiments show that Brd2 is also required for hematopoiesis. We conclude that Brd2 plays a critical, independent role in regulation of mitogenic response genes, particularly cyclin A, in B cells.

  1. Rictor positively regulates B cell receptor signaling by modulating actin reorganization via ezrin.

    Directory of Open Access Journals (Sweden)

    Lu Huang

    2017-08-01

    Full Text Available As the central hub of the metabolism machinery, the mammalian target of rapamycin complex 2 (mTORC2 has been well studied in lymphocytes. As an obligatory component of mTORC2, the role of Rictor in T cells is well established. However, the role of Rictor in B cells still remains elusive. Rictor is involved in B cell development, especially the peripheral development. However, the role of Rictor on B cell receptor (BCR signaling as well as the underlying cellular and molecular mechanism is still unknown. This study used B cell-specfic Rictor knockout (KO mice to investigate how Rictor regulates BCR signaling. We found that the key positive and negative BCR signaling molecules, phosphorylated Brutons tyrosine kinase (pBtk and phosphorylated SH2-containing inositol phosphatase (pSHIP, are reduced and enhanced, respectively, in Rictor KO B cells. This suggests that Rictor positively regulates the early events of BCR signaling. We found that the cellular filamentous actin (F-actin is drastically increased in Rictor KO B cells after BCR stimulation through dysregulating the dephosphorylation of ezrin. The high actin-ezrin intensity area restricts the lateral movement of BCRs upon stimulation, consequently reducing BCR clustering and BCR signaling. The reduction in the initiation of BCR signaling caused by actin alteration is associated with a decreased humoral immune response in Rictor KO mice. The inhibition of actin polymerization with latrunculin in Rictor KO B cells rescues the defects of BCR signaling and B cell differentiation. Overall, our study provides a new pathway linking cell metablism to BCR activation, in which Rictor regulates BCR signaling via actin reorganization.

  2. B cell-derived transforming growth factor-β1 expression limits the induction phase of autoimmune neuroinflammation.

    Science.gov (United States)

    Bjarnadóttir, Kristbjörg; Benkhoucha, Mahdia; Merkler, Doron; Weber, Martin S; Payne, Natalie L; Bernard, Claude C A; Molnarfi, Nicolas; Lalive, Patrice H

    2016-10-06

    Studies in experimental autoimmune encephalomyelitis (EAE), a murine model of multiple sclerosis (MS), have shown that regulatory B cells modulate the course of the disease via the production of suppressive cytokines. While data indicate a role for transforming growth factor (TGF)-β1 expression in regulatory B cell functions, this mechanism has not yet been tested in autoimmune neuroinflammation. Transgenic mice deficient for TGF-β1 expression in B cells (B-TGF-β1 -/- ) were tested in EAE induced by recombinant mouse myelin oligodendrocyte glycoprotein (rmMOG). In this model, B-TGF-β1 -/- mice showed an earlier onset of neurologic impairment compared to their littermate controls. Exacerbated EAE susceptibility in B-TGF-β1 -/- mice was associated with augmented CNS T helper (Th)1/17 responses. Moreover, selective B cell TGF-β1-deficiency increased the frequencies and activation of myeloid dendritic cells, potent professional antigen-presenting cells (APCs), suggesting that B cell-derived TGF-β1 can constrain Th1/17 responses through inhibition of APC activity. Collectively our data suggest that B cells can down-regulate the function of APCs, and in turn encephalitogenic Th1/17 responses, via TGF-β1, findings that may be relevant to B cell-targeted therapies.

  3. Co-stimulation by anti-immunoglobulin is required for B cell activation by CD40Llow T cells

    DEFF Research Database (Denmark)

    Poudrier, J; Owens, T

    1994-01-01

    cell Ag specificity by using anti-CD3/T cell receptor (TcR) monoclonal antibodies (mAb) to activate T cells. To study the role of sIg engagement in the responsiveness of B cells to T help, we pre-treated small resting B cells with soluble anti-kappa mAb prior to contact with an activated Th1 clone...... strongly. Low buoyant density B cells also responded to CD40Llow Th cells. There was no B cell response to resting Th cells. mAb against CD54/intercellular adhesion molecule-1 or major histocompatibility complex (MHC) class II completely inhibited B cell responses to CD40Llow Th1 cells, equivalent...

  4. Scientific and Regulatory Policy Committee Points-to-consider Paper*: Drug-induced Vascular Injury Associated with Nonsmall Molecule Therapeutics in Preclinical Development: Part 2. Antisense Oligonucleotides.

    Science.gov (United States)

    Engelhardt, Jeffery A; Fant, Pierluigi; Guionaud, Silvia; Henry, Scott P; Leach, Michael W; Louden, Calvert; Scicchitano, Marshall S; Weaver, James L; Zabka, Tanja S; Frazier, Kendall S

    2015-10-01

    Drug-induced vascular injury (DIVI) is a recurrent challenge in the development of novel pharmaceutical agents. In recent years, DIVI has been occasionally observed in nonhuman primates given RNA-targeting therapeutics such as antisense oligonucleotide therapies (ASOs) during chronic toxicity studies. While DIVI in laboratory animal species has been well characterized for vasoactive small molecules, and immune-mediated responses against large molecule biotherapeutics have been well described, there is little published information regarding DIVI induced by ASOs to date. Preclinical DIVI findings in monkeys have caused considerable delays in development of promising new ASO therapies, because of the uncertainty about whether DIVI in preclinical studies is predictive of effects in humans, and the lack of robust biomarkers of DIVI. This review of DIVI discusses clinical and microscopic features of vasculitis in monkeys, their pathogenic mechanisms, and points to consider for the toxicologist and pathologist when confronted with ASO-related DIVI. Relevant examples of regulatory feedback are included to provide insight into risk assessment of ASO therapies. © 2015 by The Author(s).

  5. Potential importance of B cells in aging and aging-associated neurodegenerative diseases.

    Science.gov (United States)

    Biragyn, Arya; Aliseychik, Maria; Rogaev, Evgeny

    2017-04-01

    Our understanding of B cells as merely antibody producers is slowly changing. Alone or in concert with antibody, they control outcomes of seemingly different diseases such as cancer, rheumatoid arthritis, diabetes, and multiple sclerosis. While their role in activation of effector immune cells is beneficial in cancer but bad in autoimmune diseases, their immunosuppressive and regulatory subsets (Bregs) inhibit autoimmune and anticancer responses. These pathogenic and suppressive functions are not static and appear to be regulated by the nature and strength of inflammation. Although aging increases inflammation and changes the composition and function of B cells, surprisingly, little is known whether the change affects aging-associated neurodegenerative disease, such as Alzheimer's disease (AD). Here, by analyzing B cells in cancer and autoimmune and neuroinflammatory diseases, we elucidate their potential importance in AD and other aging-associated neuroinflammatory diseases.

  6. Follicular B Cells Promote Atherosclerosis via T Cell-Mediated Differentiation Into Plasma Cells and Secreting Pathogenic Immunoglobulin G.

    Science.gov (United States)

    Tay, Christopher; Liu, Yu-Han; Kanellakis, Peter; Kallies, Axel; Li, Yi; Cao, Anh; Hosseini, Hamid; Tipping, Peter; Toh, Ban-Hock; Bobik, Alex; Kyaw, Tin

    2018-05-01

    B cells promote or protect development of atherosclerosis. In this study, we examined the role of MHCII (major histocompatibility II), CD40 (cluster of differentiation 40), and Blimp-1 (B-lymphocyte-induced maturation protein) expression by follicular B (FO B) cells in development of atherosclerosis together with the effects of IgG purified from atherosclerotic mice. Using mixed chimeric Ldlr -/- mice whose B cells are deficient in MHCII or CD40, we demonstrate that these molecules are critical for the proatherogenic actions of FO B cells. During development of atherosclerosis, these deficiencies affected T-B cell interactions, germinal center B cells, plasma cells, and IgG. As FO B cells differentiating into plasma cells require Blimp-1, we also assessed its role in the development of atherosclerosis. Blimp-1-deficient B cells greatly attenuated atherosclerosis and immunoglobulin-including IgG production, preventing IgG accumulation in atherosclerotic lesions; Blimp-1 deletion also attenuated lesion proinflammatory cytokines, apoptotic cell numbers, and necrotic core. To determine the importance of IgG for atherosclerosis, we purified IgG from atherosclerotic mice. Their transfer but not IgG from nonatherosclerotic mice into Ldlr -/- mice whose B cells are Blimp-1-deficient increased atherosclerosis; transfer was associated with IgG accumulating in atherosclerotic lesions, increased lesion inflammatory cytokines, apoptotic cell numbers, and necrotic core size. The mechanism by which FO B cells promote atherosclerosis is highly dependent on their expression of MHCII, CD40, and Blimp-1. FO B cell differentiation into IgG-producing plasma cells also is critical for their proatherogenic actions. Targeting B-T cell interactions and pathogenic IgG may provide novel therapeutic strategies to prevent atherosclerosis and its adverse cardiovascular complications. © 2018 American Heart Association, Inc.

  7. B cell lymphoma and myeloma in murine Gaucher's disease

    NARCIS (Netherlands)

    Pavlova, E. V.; Wang, S. Z.; Archer, J.; Dekker, N. [=Nick; Aerts, J. M. F. G.; Karlsson, S.; Cox, T. M.

    2013-01-01

    Multiple myeloma and B cell lymphoma are leading causes of death in Gaucher's disease but the nature of the stimulus driving the often noted clonal expansion of immunoglobulin-secreting B cells and cognate lymphoid malignancy is unknown. We investigated the long-term development of B cell

  8. Unique B cell differentiation profile in tolerant kidney transplant patients.

    Science.gov (United States)

    Chesneau, M; Pallier, A; Braza, F; Lacombe, G; Le Gallou, S; Baron, D; Giral, M; Danger, R; Guerif, P; Aubert-Wastiaux, H; Néel, A; Michel, L; Laplaud, D-A; Degauque, N; Soulillou, J-P; Tarte, K; Brouard, S

    2014-01-01

    Operationally tolerant patients (TOL) display a higher number of blood B cells and transcriptional B cell signature. As they rarely develop an allo-immune response, they could display an abnormal B cell differentiation. We used an in vitro culture system to explore T-dependent differentiation of B cells into plasma cells. B cell phenotype, apoptosis, proliferation, cytokine, immunoglobulin production and markers of differentiation were followed in blood of these patients. Tolerant recipients show a higher frequency of CD20(+) CD24(hi) CD38(hi) transitional and CD20(+) CD38(lo) CD24(lo) naïve B cells compared to patients with stable graft function, correlating with a decreased frequency of CD20(-) CD38(+) CD138(+) differentiated plasma cells, suggestive of abnormal B cell differentiation. B cells from TOL proliferate normally but produce more IL-10. In addition, B cells from tolerant recipients exhibit a defective expression of factors of the end step of differentiation into plasma cells and show a higher propensity for cell death apoptosis compared to patients with stable graft function. This in vitro profile is consistent with down-regulation of B cell differentiation genes and anti-apoptotic B cell genes in these patients in vivo. These data suggest that a balance between B cells producing IL-10 and a deficiency in plasma cells may encourage an environment favorable to the tolerance maintenance. © Copyright 2013 The American Society of Transplantation and the American Society of Transplant Surgeons.

  9. Expression of Tumor Necrosis Factor Receptor 2 Characterizes TLR9-Driven Formation of Interleukin-10-Producing B Cells

    Directory of Open Access Journals (Sweden)

    Olga Ticha

    2018-01-01

    Full Text Available B cell-derived interleukin-10 (IL-10 production has been described as a hallmark for regulatory function in B lymphocytes. However, there is an ongoing debate on the origin of IL-10-secreting B cells and lack of specific surface markers has turned into an important obstacle for studying human B regulatory cells. In this study, we propose that tumor necrosis factor receptor 2 (TNFR2 expression can be used for enrichment of IL-10-secreting B cells. Our data confirm that IL-10 production can be induced by TLR9 stimulation with CpG ODN and that IL-10 secretion accompanies differentiation of peripheral blood B cells into plasma blasts. We further show that CpG ODN stimulation induces TNFR2 expression, which correlates with IL-10 secretion and terminal differentiation. Indeed, flow cytometric sorting of TNFR2+ B cells revealed that TNFR2+ and TNFR2− fractions correspond to IL-10+ and IL-10− fractions, respectively. Furthermore, CpG-induced TNFR2+ B cells were predominantly found in the IgM+ CD27+ B cell subset and spontaneously released immunoglobulin. Finally, our data corroborate the functional impact of TNFR2 by demonstrating that stimulation with a TNFR2 agonist significantly augments IL-10 and IL-6 production in B cells. Altogether, our data highlight a new role for TNFR2 in IL-10-secreting human B lymphocytes along with the potential to exploit this finding for sorting and isolation of this currently ill-defined B cell subset.

  10. Intravascular Large B-Cell Lymphoma

    Directory of Open Access Journals (Sweden)

    Maria S. Khan MD, FACP

    2014-03-01

    Full Text Available Case Presentation . A 69-year-old Hispanic male, with a past history of diabetes and coronary disease, was admitted for fever, diarrhea, and confusion of 4 weeks duration. Physical examination showed a disoriented patient with multiple ecchymoses, possible ascites, and bilateral scrotal swelling. Hemoglobin was 6.7, prothrombin time (PT 21.4 seconds with international normalized ratio 2.1, partial thromboplastin time (PTT 55.6 seconds, fibrin split 10 µg/L, and lactate dehydrogenase (LDH 1231 IU/L. Except for a positive DNA test for Epstein–Barr virus (EBV infection, extensive diagnostic workup for infections, malignancy, or a neurological cause was negative. Mixing studies revealed a nonspecific inhibitor of PT and PTT but Factor VIII levels were normal. The patient was empirically treated with antibiotics but developed hypotension and died on day 27 of admission. At autopsy, patient was found to have intravascular diffuse large B-cell lymphoma involving skin, testes, lung, and muscles. The malignant cells were positive for CD20, CD791, Mum-1, and Pax-5 and negative for CD3, CD5, CD10, CD30, and Bcl-6. The malignant cells were 100% positive for Ki-67. Discussion . Intravascular large cell B-cell lymphoma (IVLBCL is rare form of diffuse large B-cell lymphoma and tends to proliferate within small blood vessels, particularly capillaries and postcapillary venules. The cause of its affinity for vascular bed remains unknown. In many reports, IVLBCL was associated with HIV, HHV8, and EBV infections. The fact that our case showed evidence of EBV infection lends support to the association of this diagnosis to viral illness. The available literature on this subject is scant, and in many cases, the diagnosis was made only at autopsy. The typical presentation of this disorder is with B symptoms, progressive neurologic deficits, and skin findings. Bone marrow, spleen, and liver are involved in a minority of patients. Nearly all patients have elevated LDH

  11. B-CELL EPITOPE ON THE U1 SNRNP-C AUTOANTIGEN CONTAINS A SEQUENCE SIMILAR TO THAT OF THE HERPES-SIMPLEX VIRUS PROTEIN

    NARCIS (Netherlands)

    MISAKI, Y; YAMAMOTO, K; YANAGI, K; MIURA, H; ICHIJO, H; KATO, T; MATO, T; WELLINGWESTER, S; NISHIOKA, K; ITO, K

    The mechanism of autoantibody production in autoimmune diseases is not well understood. In the present study we performed the B cell epitope mapping of the U1 small nuclear ribonucleoprotein (snRNP)-C, one of the target molecules of anti-nRNP autoantibody to investigate how B cells respond to the

  12. Cell of origin associated classification of B-cell malignancies by gene signatures of the normal B-cell hierarchy.

    Science.gov (United States)

    Johnsen, Hans Erik; Bergkvist, Kim Steve; Schmitz, Alexander; Kjeldsen, Malene Krag; Hansen, Steen Møller; Gaihede, Michael; Nørgaard, Martin Agge; Bæch, John; Grønholdt, Marie-Louise; Jensen, Frank Svendsen; Johansen, Preben; Bødker, Julie Støve; Bøgsted, Martin; Dybkær, Karen

    2014-06-01

    Recent findings have suggested biological classification of B-cell malignancies as exemplified by the "activated B-cell-like" (ABC), the "germinal-center B-cell-like" (GCB) and primary mediastinal B-cell lymphoma (PMBL) subtypes of diffuse large B-cell lymphoma and "recurrent translocation and cyclin D" (TC) classification of multiple myeloma. Biological classification of B-cell derived cancers may be refined by a direct and systematic strategy where identification and characterization of normal B-cell differentiation subsets are used to define the cancer cell of origin phenotype. Here we propose a strategy combining multiparametric flow cytometry, global gene expression profiling and biostatistical modeling to generate B-cell subset specific gene signatures from sorted normal human immature, naive, germinal centrocytes and centroblasts, post-germinal memory B-cells, plasmablasts and plasma cells from available lymphoid tissues including lymph nodes, tonsils, thymus, peripheral blood and bone marrow. This strategy will provide an accurate image of the stage of differentiation, which prospectively can be used to classify any B-cell malignancy and eventually purify tumor cells. This report briefly describes the current models of the normal B-cell subset differentiation in multiple tissues and the pathogenesis of malignancies originating from the normal germinal B-cell hierarchy.

  13. B Cell Receptor-Mediated Internalization of Salmonella: A Novel Pathway for Autonomous B Cell Activation and Antibody Production

    NARCIS (Netherlands)

    Souwer, Yuri; Griekspoor, Alexander; Jorritsma, Tineke; de Wit, Jelle; Janssen, Hans; Neefjes, Jacques; van Ham, S. Marieke

    2009-01-01

    The present paradigm is that primary B cells are nonphagocytosing cells. In this study, we demonstrate that human primary B cells are able to internalize bacteria when the bacteria are recognized by the BCR. BCR-mediated internalization of Salmonella typhimurium results in B cell differentiation and

  14. Regulation of normal B-cell differentiation and malignant B-cell survival by OCT2.

    Science.gov (United States)

    Hodson, Daniel J; Shaffer, Arthur L; Xiao, Wenming; Wright, George W; Schmitz, Roland; Phelan, James D; Yang, Yandan; Webster, Daniel E; Rui, Lixin; Kohlhammer, Holger; Nakagawa, Masao; Waldmann, Thomas A; Staudt, Louis M

    2016-04-05

    The requirement for the B-cell transcription factor OCT2 (octamer-binding protein 2, encoded by Pou2f2) in germinal center B cells has proved controversial. Here, we report that germinal center B cells are formed normally after depletion of OCT2 in a conditional knockout mouse, but their proliferation is reduced and in vivo differentiation to antibody-secreting plasma cells is blocked. This finding led us to examine the role of OCT2 in germinal center-derived lymphomas. shRNA knockdown showed that almost all diffuse large B-cell lymphoma (DLBCL) cell lines are addicted to the expression of OCT2 and its coactivator OCA-B. Genome-wide chromatin immunoprecipitation (ChIP) analysis and gene-expression profiling revealed the broad transcriptional program regulated by OCT2 that includes the expression of STAT3, IL-10, ELL2, XBP1, MYC, TERT, and ADA. Importantly, genetic alteration of OCT2 is not a requirement for cellular addiction in DLBCL. However, we detected amplifications of the POU2F2 locus in DLBCL tumor biopsies and a recurrent mutation of threonine 223 in the DNA-binding domain of OCT2. This neomorphic mutation subtly alters the DNA-binding preference of OCT2, leading to the transactivation of noncanonical target genes including HIF1a and FCRL3 Finally, by introducing mutations designed to disrupt the OCT2-OCA-B interface, we reveal a requirement for this protein-protein interface that ultimately might be exploited therapeutically. Our findings, combined with the predominantly B-cell-restricted expression of OCT2 and the absence of a systemic phenotype in our knockout mice, suggest that an OCT2-targeted therapeutic strategy would be efficacious in both major subtypes of DLBCL while avoiding systemic toxicity.

  15. CD40 signaling synergizes with TLR-2 in the BCR independent activation of resting B cells.

    Directory of Open Access Journals (Sweden)

    Shweta Jain

    Full Text Available Conventionally, signaling through BCR initiates sequence of events necessary for activation and differentiation of B cells. We report an alternative approach, independent of BCR, for stimulating resting B (RB cells, by involving TLR-2 and CD40--molecules crucial for innate and adaptive immunity. CD40 triggering of TLR-2 stimulated RB cells significantly augments their activation, proliferation and differentiation. It also substantially ameliorates the calcium flux, antigen uptake capacity and ability of B cells to activate T cells. The survival of RB cells was improved and it increases the number of cells expressing activation induced deaminase (AID, signifying class switch recombination (CSR. Further, we also observed increased activation rate and decreased threshold period required for optimum stimulation of RB cells. These results corroborate well with microarray gene expression data. This study provides novel insights into coordination between the molecules of innate and adaptive immunity in activating B cells, in a BCR independent manner. This strategy can be exploited to design vaccines to bolster B cell activation and antigen presenting efficiency, leading to faster and better immune response.

  16. CD40 signaling synergizes with TLR-2 in the BCR independent activation of resting B cells.

    Science.gov (United States)

    Jain, Shweta; Chodisetti, Sathi Babu; Agrewala, Javed N

    2011-01-01

    Conventionally, signaling through BCR initiates sequence of events necessary for activation and differentiation of B cells. We report an alternative approach, independent of BCR, for stimulating resting B (RB) cells, by involving TLR-2 and CD40--molecules crucial for innate and adaptive immunity. CD40 triggering of TLR-2 stimulated RB cells significantly augments their activation, proliferation and differentiation. It also substantially ameliorates the calcium flux, antigen uptake capacity and ability of B cells to activate T cells. The survival of RB cells was improved and it increases the number of cells expressing activation induced deaminase (AID), signifying class switch recombination (CSR). Further, we also observed increased activation rate and decreased threshold period required for optimum stimulation of RB cells. These results corroborate well with microarray gene expression data. This study provides novel insights into coordination between the molecules of innate and adaptive immunity in activating B cells, in a BCR independent manner. This strategy can be exploited to design vaccines to bolster B cell activation and antigen presenting efficiency, leading to faster and better immune response.

  17. Semaphorin 4C Protects against Allergic Inflammation: Requirement of Regulatory CD138+ Plasma Cells.

    Science.gov (United States)

    Xue, Di; Kaufman, Gabriel N; Dembele, Marieme; Beland, Marianne; Massoud, Amir H; Mindt, Barbara C; Fiter, Ryan; Fixman, Elizabeth D; Martin, James G; Friedel, Roland H; Divangahi, Maziar; Fritz, Jörg H; Mazer, Bruce D

    2017-01-01

    The regulatory properties of B cells have been studied in autoimmune diseases; however, their role in allergic diseases is poorly understood. We demonstrate that Semaphorin 4C (Sema4C), an axonal guidance molecule, plays a crucial role in B cell regulatory function. Mice deficient in Sema4C exhibited increased airway inflammation after allergen exposure, with massive eosinophilic lung infiltrates and increased Th2 cytokines. This phenotype was reproduced by mixed bone marrow chimeric mice with Sema4C deficient only in B cells, indicating that B lymphocytes were the key cells affected by the absence of Sema4C expression in allergic inflammation. We determined that Sema4C-deficient CD19 + CD138 + cells exhibited decreased IL-10 and increased IL-4 expression in vivo and in vitro. Adoptive transfer of Sema4c -/- CD19 + CD138 + cells induced marked pulmonary inflammation, eosinophilia, and increased bronchoalveolar lavage fluid IL-4 and IL-5, whereas adoptive transfer of wild-type CD19 + CD138 + IL-10 + cells dramatically decreased allergic airway inflammation in wild-type and Sema4c -/- mice. This study identifies a novel pathway by which Th2-mediated immune responses are regulated. It highlights the importance of plasma cells as regulatory cells in allergic inflammation and suggests that CD138 + B cells contribute to cytokine balance and are important for maintenance of immune homeostasis in allergic airways disease. Furthermore, we demonstrate that Sema4C is critical for optimal regulatory cytokine production in CD138 + B cells. Copyright © 2016 by The American Association of Immunologists, Inc.

  18. Eμ/miR-125b transgenic mice develop lethal B-cell malignancies.

    Science.gov (United States)

    Enomoto, Y; Kitaura, J; Hatakeyama, K; Watanuki, J; Akasaka, T; Kato, N; Shimanuki, M; Nishimura, K; Takahashi, M; Taniwaki, M; Haferlach, C; Siebert, R; Dyer, M J S; Asou, N; Aburatani, H; Nakakuma, H; Kitamura, T; Sonoki, T

    2011-12-01

    MicroRNA-125b-1 (miR-125b-1) is a target of a chromosomal translocation t(11;14)(q24;q32) recurrently found in human B-cell precursor acute lymphoblastic leukemia (BCP-ALL). This translocation results in overexpression of miR-125b controlled by immunoglobulin heavy chain gene (IGH) regulatory elements. In addition, we found that six out of twenty-one BCP-ALL patients without t(11;14)(q24;q32) showed overexpression of miR-125b. Interestingly, four out of nine patients with BCR/ABL-positive BCP-ALL and one patient with B-cell lymphoid crisis that had progressed from chronic myelogenous leukemia overexpressed miR-125b. To examine the role of the deregulated expression of miR-125b in the development of B-cell tumor in vivo, we generated transgenic mice mimicking the t(11;14)(q24;q32) (Eμ/miR-125b-TG mice). Eμ/miR-125b-TG mice overexpressed miR-125b driven by IGH enhancer and promoter and developed IgM-negative or IgM-positive lethal B-cell malignancies with clonal proliferation. B cells obtained from the Eμ/miR-125b-TG mice were resistant to apoptosis induced by serum starvation. We identified Trp53inp1, a pro-apoptotic gene induced by cell stress, as a novel target gene of miR-125b in hematopoietic cells in vitro and in vivo. Our results provide direct evidence that miR-125b has important roles in the tumorigenesis of precursor B cells.

  19. Adipose Tissue Inflammation Induces B Cell Inflammation and Decreases B Cell Function in Aging

    Directory of Open Access Journals (Sweden)

    Daniela Frasca

    2017-08-01

    Full Text Available Aging is the greatest risk factor for developing chronic diseases. Inflamm-aging, the age-related increase in low-grade chronic inflammation, may be a common link in age-related diseases. This review summarizes recent published data on potential cellular and molecular mechanisms of the age-related increase in inflammation, and how these contribute to decreased humoral immune responses in aged mice and humans. Briefly, we cover how aging and related inflammation decrease antibody responses in mice and humans, and how obesity contributes to the mechanisms for aging through increased inflammation. We also report data in the literature showing adipose tissue infiltration with immune cells and how these cells are recruited and contribute to local and systemic inflammation. We show that several types of immune cells infiltrate the adipose tissue and these include macrophages, neutrophils, NK cells, innate lymphoid cells, eosinophils, T cells, B1, and B2 cells. Our main focus is how the adipose tissue affects immune responses, in particular B cell responses and antibody production. The role of leptin in generating inflammation and decreased B cell responses is also discussed. We report data published by us and by other groups showing that the adipose tissue generates pro-inflammatory B cell subsets which induce pro-inflammatory T cells, promote insulin resistance, and secrete pathogenic autoimmune antibodies.

  20. Brucella abortus-infected B cells induce osteoclastogenesis.

    Science.gov (United States)

    Pesce Viglietti, Ayelén Ivana; Arriola Benitez, Paula Constanza; Giambartolomei, Guillermo Hernán; Delpino, María Victoria

    2016-09-01

    Brucella abortus is an intracellular bacterium that establishes lifelong infections in livestock and humans although the mechanisms of its chronicity are poorly understood. Activated B cells have long lifespan and B. abortus infection activates B cells. Our results indicate that the direct infection of B cells with B. abortus induced matrix metalloproteinase-9 (MMP-9), receptor activator for NF κB ligand (RANKL), tumor necrosis factor (TNF)-α and interleukin (IL)-6 secretion. In addition, supernatants from B. abortus-infected B cells induced bone marrow-derived monocytes to undergo osteoclastogenesis. Using osteoprotegerin, RANKL's decoy receptor, we determined that RANKL is involved in osteoclastogenesis induced by supernatants from B. abortus-infected B cells. The results presented here shed light on how the interactions of B. abortus with B cells may have a role in the pathogenesis of brucellar osteoarticular disease. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  1. Differential programming of B cells in AID deficient mice.

    Directory of Open Access Journals (Sweden)

    Marc A Hogenbirk

    Full Text Available The Aicda locus encodes the activation induced cytidine deaminase (AID and is highly expressed in germinal center (GC B cells to initiate somatic hypermutation (SHM and class switch recombination (CSR of immunoglobulin (Ig genes. Besides these Ig specific activities in B cells, AID has been implicated in active DNA demethylation in non-B cell systems. We here determined a potential role of AID as an epigenetic eraser and transcriptional regulator in B cells. RNA-Seq on different B cell subsets revealed that Aicda(-/- B cells are developmentally affected. However as shown by RNA-Seq, MethylCap-Seq, and SNP analysis these transcriptome alterations may not relate to AID, but alternatively to a CBA mouse strain derived region around the targeted Aicda locus. These unexpected confounding parameters provide alternative, AID-independent interpretations on genotype-phenotype correlations previously reported in numerous studies on AID using the Aicda(-/- mouse strain.

  2. Restoring balance to B cells in ADA deficiency.

    Science.gov (United States)

    Luning Prak, Eline T

    2012-06-01

    It is paradoxical that immunodeficiency disorders are associated with autoimmunity. Adenosine deaminase (ADA) deficiency, a cause of X-linked severe combined immunodeficiency (SCID), is a case in point. In this issue of the JCI, Sauer and colleagues investigate the B cell defects in ADA-deficient patients. They demonstrate that ADA patients receiving enzyme replacement therapy had B cell tolerance checkpoint defects. Remarkably, gene therapy with a retrovirus that expresses ADA resulted in the apparent correction of these defects, with normalization of peripheral B cell autoantibody frequencies. In vitro, agents that either block ADA or overexpress adenosine resulted in altered B cell receptor and TLR signaling. Collectively, these data implicate a B cell-intrinsic mechanism for alterations in B cell tolerance in the setting of partial ADA deficiency that is corrected by gene therapy.

  3. Tolerance without clonal expansion: self-antigen-expressing B cells program self-reactive T cells for future deletion.

    Science.gov (United States)

    Frommer, Friederike; Heinen, Tobias J A J; Wunderlich, F Thomas; Yogev, Nir; Buch, Thorsten; Roers, Axel; Bettelli, Estelle; Müller, Werner; Anderton, Stephen M; Waisman, Ari

    2008-10-15

    B cells have been shown in various animal models to induce immunological tolerance leading to reduced immune responses and protection from autoimmunity. We show that interaction of B cells with naive T cells results in T cell triggering accompanied by the expression of negative costimulatory molecules such as PD-1, CTLA-4, B and T lymphocyte attenuator, and CD5. Following interaction with B cells, T cells were not induced to proliferate, in a process that was dependent on their expression of PD-1 and CTLA-4, but not CD5. In contrast, the T cells became sensitive to Ag-induced cell death. Our results demonstrate that B cells participate in the homeostasis of the immune system by ablation of conventional self-reactive T cells.

  4. Entry of Francisella tularensis into Murine B Cells: The Role of B Cell Receptors and Complement Receptors.

    Directory of Open Access Journals (Sweden)

    Lenka Plzakova

    Full Text Available Francisella tularensis, the etiological agent of tularemia, is an intracellular pathogen that dominantly infects and proliferates inside phagocytic cells but can be seen also in non-phagocytic cells, including B cells. Although protective immunity is known to be almost exclusively associated with the type 1 pathway of cellular immunity, a significant role of B cells in immune responses already has been demonstrated. Whether their role is associated with antibody-dependent or antibody-independent B cell functions is not yet fully understood. The character of early events during B cell-pathogen interaction may determine the type of B cell response regulating the induction of adaptive immunity. We used fluorescence microscopy and flow cytometry to identify the basic requirements for the entry of F. tularensis into B cells within in vivo and in vitro infection models. Here, we present data showing that Francisella tularensis subsp. holarctica strain LVS significantly infects individual subsets of murine peritoneal B cells early after infection. Depending on a given B cell subset, uptake of Francisella into B cells is mediated by B cell receptors (BCRs with or without complement receptor CR1/2. However, F. tularensis strain FSC200 ΔiglC and ΔftdsbA deletion mutants are defective in the ability to enter B cells. Once internalized into B cells, F. tularensis LVS intracellular trafficking occurs along the endosomal pathway, albeit without significant multiplication. The results strongly suggest that BCRs alone within the B-1a subset can ensure the internalization process while the BCRs on B-1b and B-2 cells need co-signaling from the co receptor containing CR1/2 to initiate F. tularensis engulfment. In this case, fluidity of the surface cell membrane is a prerequisite for the bacteria's internalization. The results substantially underline the functional heterogeneity of B cell subsets in relation to F. tularensis.

  5. Ups and Downs of Poised RNA Polymerase II in B-Cells.

    Directory of Open Access Journals (Sweden)

    Phuong Dao

    2016-04-01

    Full Text Available Recent genome-wide analyses have uncovered a high accumulation of RNA polymerase II (Pol II at the 5' end of genes. This elevated Pol II presence at promoters, referred to here as Poll II poising, is mainly (but not exclusively attributed to temporal pausing of transcription during early elongation which, in turn, has been proposed to be a regulatory step for processes that need to be activated "on demand". Yet, the full genome-wide regulatory role of Pol II poising is yet to be delineated. To elucidate the role of Pol II poising in B cell activation, we compared Pol II profiles in resting and activated B cells. We found that while Pol II poised genes generally overlap functionally among different B cell states and correspond to the functional groups previously identified for other cell types, non-poised genes are B cell state specific. Focusing on the changes in transcription activity upon B cell activation, we found that the majority of such changes were from poised to non-poised state. The genes showing this type of transition were functionally enriched in translation, RNA processing and mRNA metabolic process. Interestingly, we also observed a transition from non-poised to poised state. Within this set of genes we identified several Immediate Early Genes (IEG, which were highly expressed in resting B cell and shifted from non-poised to poised state after B cell activation. Thus Pol II poising does not only mark genes for rapid expression in the future, but it is also associated with genes that are silenced after a burst of their expression. Finally, we performed comparative analysis of the presence of G4 motifs in the context of poised versus non-poised but active genes. Interestingly we observed a differential enrichment of these motifs upstream versus downstream of TSS depending on poising status. The enrichment of G4 sequence motifs upstream of TSS of non-poised active genes suggests a potential role of quadruplexes in expression

  6. Anti-B cell antibody therapies for inflammatory rheumatic diseases

    DEFF Research Database (Denmark)

    Faurschou, Mikkel; Jayne, David R W

    2014-01-01

    Several monoclonal antibodies targeting B cells have been tested as therapeutics for inflammatory rheumatic diseases. We review important observations from randomized clinical trials regarding the efficacy and safety of anti-B cell antibody-based therapies for rheumatoid arthritis, systemic lupus...... and functions in rheumatic disorders. Future studies should also evaluate how to maintain disease control by means of conventional and/or biologic immunosuppressants after remission-induction with anti-B cell antibodies....

  7. Leukemia - B-Cell Prolymphocytic Leukemia and Hairy Cell Leukemia

    Science.gov (United States)

    ... Leukemia - B-cell Prolymphocytic Leukemia and Hairy Cell Leukemia Introduction Statistics Risk Factors Symptoms and Signs Diagnosis Stages Treatment Options About Clinical Trials Latest Research ...

  8. B cells as a target of immune modulation

    Directory of Open Access Journals (Sweden)

    Hawker Kathleen

    2009-01-01

    Full Text Available B cells have recently been identified as an integral component of the immune system; they play a part in autoimmunity through antigen presentation, antibody secretion, and complement activation. Animal models of multiple sclerosis (MS suggest that myelin destruction is partly mediated through B cell activation (and plasmablasts. MS patients with evidence of B cell involvement, as compared to those without, tend to have a worse prognosis. Finally, the significant decrease in new gadolinium-enhancing lesions, new T2 lesions, and relapses in MS patients treated with rituximab (a monoclonal antibody against CD20 on B cells leads us to the conclusion that B cells play an important role in MS and that immune modulation of these cells may ameliorate the disease. This article will explore the role of B cells in MS and the rationale for the development of B cell-targeted therapeutics. MS is an immune-mediated disease that affects over 2 million people worldwide and is the number one cause of disability in young patients. Most therapeutic targets have focused on T cells; however, recently, the focus has shifted to the role of B cells in the pathogenesis of MS and the potential of B cells as a therapeutic target.

  9. CD8 Follicular T Cells Promote B Cell Antibody Class Switch in Autoimmune Disease.

    Science.gov (United States)

    Valentine, Kristen M; Davini, Dan; Lawrence, Travis J; Mullins, Genevieve N; Manansala, Miguel; Al-Kuhlani, Mufadhal; Pinney, James M; Davis, Jason K; Beaudin, Anna E; Sindi, Suzanne S; Gravano, David M; Hoyer, Katrina K

    2018-05-09

    CD8 T cells can play both a protective and pathogenic role in inflammation and autoimmune development. Recent studies have highlighted the ability of CD8 T cells to function as T follicular helper (Tfh) cells in the germinal center in the context of infection. However, whether this phenomenon occurs in autoimmunity and contributes to autoimmune pathogenesis is largely unexplored. In this study, we show that CD8 T cells acquire a CD4 Tfh profile in the absence of functional regulatory T cells in both the IL-2-deficient and scurfy mouse models. Depletion of CD8 T cells mitigates autoimmune pathogenesis in IL-2-deficient mice. CD8 T cells express the B cell follicle-localizing chemokine receptor CXCR5, a principal Tfh transcription factor Bcl6, and the Tfh effector cytokine IL-21. CD8 T cells localize to the B cell follicle, express B cell costimulatory proteins, and promote B cell differentiation and Ab isotype class switching. These data reveal a novel contribution of autoreactive CD8 T cells to autoimmune disease, in part, through CD4 follicular-like differentiation and functionality. Copyright © 2018 by The American Association of Immunologists, Inc.

  10. EVALUATION OF CYTOKINE GENE POLYMORPHISM IN B CELL LYMPHOID MALIGNANCIES

    Directory of Open Access Journals (Sweden)

    E. L. Nazarova

    2014-01-01

    Full Text Available Previous studies with some solid tumors has shown that polymorphisms of certain cytokine genes may be used as predictors of clinical outcome in the patients. It seemed important to evaluate potential correlations between production of certain pro- and anti-inflammatory cytokines and co-receptor molecules, and promoter polymorphism of the cytokine genes involved into regulation of cell proliferation, differentiation, apoptosis, lipid metabolism and blood clotting in the patients with hematological malignancies. The article contains our results concerning associations between of IL-1β, -2, -4, -10, -17, TNFα, and allelic polymorphisms of their genes in 62 patients with B cell lymphoid malignancies in an ethnically homogenous group (self-identified as Russians. We have shown that the GА and AA genotypes of the G-308A polymorphism in TNFα gene are significantly associated with increased production of this cytokine, being more common in aggressive non-Hodgkin lymphomas, more rare in multiple myeloma and in indolent non-Hodgkin lymphomas.

  11. Trib1 Is Overexpressed in Systemic Lupus Erythematosus, While It Regulates Immunoglobulin Production in Murine B Cells

    Directory of Open Access Journals (Sweden)

    Léa Simoni

    2018-03-01

    Full Text Available Systemic lupus erythematosus (SLE is a severe and heterogeneous autoimmune disease with a complex genetic etiology, characterized by the production of various pathogenic autoantibodies, which participate in end-organ damages. The majority of human SLE occurs in adults as a polygenic disease, and clinical flares interspersed with silent phases of various lengths characterize the usual evolution of the disease in time. Trying to understand the mechanism of the different phenotypic traits of the disease, and considering the central role of B cells in SLE, we previously performed a detailed wide analysis of gene expression variation in B cells from quiescent SLE patients. This analysis pointed out an overexpression of TRIB1. TRIB1 is a pseudokinase that has been implicated in the development of leukemia and also metabolic disorders. It is hypothesized that Trib1 plays an adapter or scaffold function in signaling pathways, notably in MAPK pathways. Therefore, we planned to understand the functional significance of TRIB1 overexpression in B cells in SLE. We produced a new knock-in model with B-cell-specific overexpression of Trib1. We showed that overexpression of Trib1 specifically in B cells does not impact B cell development nor induce any development of SLE symptoms in the mice. By contrast, Trib1 has a negative regulatory function on the production of immunoglobulins, notably IgG1, but also on the production of autoantibodies in an induced model. We observed a decrease of Erk activation in BCR-stimulated Trib1 overexpressing B cells. Finally, we searched for Trib1 partners in B cells by proteomic analysis in order to explore the regulatory function of Trib1 in B cells. Interestingly, we find an interaction between Trib1 and CD72, a negative regulator of B cells whose deficiency in mice leads to the development of autoimmunity. In conclusion, the overexpression of Trib1 could be one of the molecular pathways implicated in the negative regulation

  12. Identification of a sub-population of B cells that proliferates after infection with epstein-barr virus

    Directory of Open Access Journals (Sweden)

    Ye Jianjiang

    2011-02-01

    Full Text Available Abstract Background Epstein-Barr virus (EBV-driven B cell proliferation is critical to its subsequent persistence in the host and is a key event in the development of EBV-associated B cell diseases. Thus, inquiry into early cellular events that precede EBV-driven proliferation of B cells is essential for understanding the processes that can lead to EBV-associated B cell diseases. Methods Infection with high titers of EBV of mixed, primary B cells in different stages of differentiation occurs during primary EBV infection and in the setting of T cell-immunocompromise that predisposes to development of EBV-lymphoproliferative diseases. Using an ex vivo system that recapitulates these conditions of infection, we correlated expression of selected B cell-surface markers and intracellular cytokines with expression of EBV latency genes and cell proliferation. Results We identified CD23, CD58, and IL6, as molecules expressed at early times after EBV-infection. EBV differentially infected B cells into two distinct sub-populations of latently infected CD23+ cells: one fraction, marked as CD23hiCD58+IL6- by day 3, subsequently proliferated; another fraction, marked as CD23loCD58+, expressed IL6, a B cell growth factor, but failed to proliferate. High levels of LMP1, a critical viral oncoprotein, were expressed in individual CD23hiCD58+ and CD23loCD58+ cells, demonstrating that reduced levels of LMP1 did not explain the lack of proliferation of CD23loCD58+ cells. Differentiation stage of B cells did not appear to govern this dichotomy in outcome either. Memory or naïve B cells did not exclusively give rise to either CD23hi or IL6-expressing cells; rather memory B cells gave rise to both sub-populations of cells. Conclusions B cells are differentially susceptible to EBV-mediated proliferation despite expression of viral gene products known to be critical for continuous B cell growth. Cellular events, in addition to viral gene expression, likely play a

  13. Overexpression of Fc receptor-like 1 associated with B-cell activation during hepatitis B virus infection

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ke [Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu Province (China); Pei, Hao [Wuxi Hospital of Infectious Disease, Wuxi, Jiangsu Province (China); Huang, Biao; Yang, Run-Lin [Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu Province (China); Wu, Hang-Yuan [Wuxi Hospital of Infectious Disease, Wuxi, Jiangsu Province (China); Zhu, Xue; Zhu, Lan [Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu Province (China)

    2012-08-17

    The role of B cells in the pathogenesis of hepatitis B virus (HBV) infection has not been explored in depth. In the present study, the activation status of B cells from peripheral blood of healthy controls (N = 20) and patients with acute hepatitis B (AHB, N = 15) or chronic hepatitis B (CHB, N = 30) was evaluated by measuring the expression levels of B-cell activation markers CD69 and CD86, using quantitative real-time PCR and flow cytometry. Moreover, the potential mechanism underlying B-cell activation during HBV infection was further investigated by analyzing the expression profile of FCRL1, an intrinsic activation molecule of B cells. An elevation in the levels of B-cell activation markers including CD69 and CD86 was observed in the AHB patients (44.31 ± 9.27, 27.64 ± 9.26%) compared to CHB patients (30.35 ± 11.27, 18.41 ± 6.56%, P < 0.05), which was still higher than healthy controls (12.23 ± 7.84, 8.22 ± 3.43%, P < 0.05). Furthermore, the expression of FCRL1 was found to be similar to B-cell activation markers, which was highest in AHB patients (70.15 ± 17.11%), lowest in healthy donors (36.32 ± 9.98%, P < 0.05) and half-way between these levels in patients with CHB (55.17 ± 12.03%, P < 0.05). The results were positively associated with aberrant B-cell activation. These data suggest that B cells can play a role in HBV infection, and therefore more effort should be devoted to exploring their functions.

  14. Tissue-specific B-cell dysfunction and generalized memory B-cell loss during acute SIV infection.

    Directory of Open Access Journals (Sweden)

    Sandrine Peruchon

    Full Text Available BACKGROUND: Primary HIV-infected patients display severe and irreversible damage to different blood B-cell subsets which is not restored by highly efficient anti-retroviral therapy (HAART. Because longitudinal investigations of primary HIV-infection is limited by the availability of lymphoid organs, we studied the tissue-specific B-cell dysfunctions in acutely simian immunodeficiency virus (SIV mac251-infected Cynomolgus macaques. METHODS AND FINDINGS: Experiments were performed on three groups of macaques infected for 14, 21 or 28 days and on three groups of animals treated with HAART for two-weeks either initiated at 4 h, 7 or 14 days post-infection (p.i.. We have simultaneously compared changes in B-cell phenotypes and functions and tissue organization of B-cell areas in various lymphoid organs. We showed that SIV induced a steady decline in SIgG-expressing memory (SIgD(-CD27(+ B-cells in spleen and lymph nodes during the first 4 weeks of infection, concomitant to selective homing/sequestration of B-cells to the small intestine and spleen. SIV non-specific Ig production was transiently increased before D14p.i., whereas SIV-specific Ig production was only detectable after D14p.i., coinciding with the presence of CD8(+ T-cells and IgG-expressing plasma cells within germinal centres. Transient B-cell apoptosis on D14p.i. and commitment to terminal differentiation contributed to memory B-cell loss. HAART abrogated B-cell apoptosis, homing to the small intestine and SIV-specific Ig production but had minimal effect on early Ig production, increased B-cell proportions in spleen and loss of memory B-cells. Therefore, virus-B-cell interactions and SIV-induced inflammatory cytokines may differently contribute to early B-cell dysfunction and impaired SIV/HIV-specific antibody response. CONCLUSIONS: These data establish tissue-specific impairments in B-cell trafficking and functions and a generalized and steady memory B-cell loss in secondary lymphoid

  15. B cells promote inflammation in obesity and type 2 diabetes through regulation of T-cell function and an inflammatory cytokine profile.

    Science.gov (United States)

    DeFuria, Jason; Belkina, Anna C; Jagannathan-Bogdan, Madhumita; Snyder-Cappione, Jennifer; Carr, Jordan David; Nersesova, Yanina R; Markham, Douglas; Strissel, Katherine J; Watkins, Amanda A; Zhu, Min; Allen, Jessica; Bouchard, Jacqueline; Toraldo, Gianluca; Jasuja, Ravi; Obin, Martin S; McDonnell, Marie E; Apovian, Caroline; Denis, Gerald V; Nikolajczyk, Barbara S

    2013-03-26

    Patients with type 2 diabetes (T2D) have disease-associated changes in B-cell function, but the role these changes play in disease pathogenesis is not well established. Data herein show B cells from obese mice produce a proinflammatory cytokine profile compared with B cells from lean mice. Complementary in vivo studies show that obese B cell-null mice have decreased systemic inflammation, inflammatory B- and T-cell cytokines, adipose tissue inflammation, and insulin resistance (IR) compared with obese WT mice. Reduced inflammation in obese/insulin resistant B cell-null mice associates with an increased percentage of anti-inflammatory regulatory T cells (Tregs). This increase contrasts with the sharply decreased percentage of Tregs in obese compared with lean WT mice and suggests that B cells may be critical regulators of T-cell functions previously shown to play important roles in IR. We demonstrate that B cells from T2D (but not non-T2D) subjects support proinflammatory T-cell function in obesity/T2D through contact-dependent mechanisms. In contrast, human monocytes increase proinflammatory T-cell cytokines in both T2D and non-T2D analyses. These data support the conclusion that B cells are critical regulators of inflammation in T2D due to their direct ability to promote proinflammatory T-cell function and secrete a proinflammatory cytokine profile. Thus, B cells are potential therapeutic targets for T2D.

  16. DNA breaks early in replication in B cell cancers

    Science.gov (United States)

    Research by scientists at the NCI has identified a new class of DNA sites in cells that break early in the replication process. They found that these break sites correlate with damage often seen in B cell cancers, such as diffuse large B cell lymphoma.

  17. Relative Contributions of B Cells and Dendritic Cells from Lupus-Prone Mice to CD4+ T Cell Polarization.

    Science.gov (United States)

    Choi, Seung-Chul; Xu, Zhiwei; Li, Wei; Yang, Hong; Roopenian, Derry C; Morse, Herbert C; Morel, Laurence

    2018-05-01

    Mouse models of lupus have shown that multiple immune cell types contribute to autoimmune disease. This study sought to investigate the involvement of B cells and dendritic cells in supporting the expansion of inflammatory and regulatory CD4 + T cells that are critical for lupus pathogenesis. We used lupus-prone B6.NZM2410.Sle1.Sle2.Sle3 (TC) and congenic C57BL/6J (B6) control mice to investigate how the genetic predisposition of these two cell types controls the activity of normal B6 T cells. Using an allogeneic in vitro assay, we showed that TC B1-a and conventional B cells expanded Th17 cells significantly more than their B6 counterparts. This expansion was dependent on CD86 and IL-6 expression and mapped to the Sle1 lupus-susceptibility locus. In vivo, TC B cells promoted greater differentiation of CD4 + T cells into Th1 and follicular helper T cells than did B6 B cells, but they limited the expansion of Foxp3 regulatory CD4 + T cells to a greater extent than did B6 B cells. Finally, when normal B6 CD4 + T cells were introduced into Rag1 -/- mice, TC myeloid/stromal cells caused their heightened activation, decreased Foxp3 regulatory CD4 + T cell differentiation, and increased renal infiltration of Th1 and Th17 cells in comparison with B6 myeloid/stromal cells. The results show that B cells from lupus mice amplify inflammatory CD4 + T cells in a nonredundant manner with myeloid/stromal cells. Copyright © 2018 by The American Association of Immunologists, Inc.

  18. Murid herpesvirus-4 exploits dendritic cells to infect B cells.

    Directory of Open Access Journals (Sweden)

    Miguel Gaspar

    2011-11-01

    Full Text Available Dendritic cells (DCs play a central role in initiating immune responses. Some persistent viruses infect DCs and can disrupt their functions in vitro. However, these viruses remain strongly immunogenic in vivo. Thus what role DC infection plays in the pathogenesis of persistent infections is unclear. Here we show that a persistent, B cell-tropic gamma-herpesvirus, Murid Herpesvirus-4 (MuHV-4, infects DCs early after host entry, before it establishes a substantial infection of B cells. DC-specific virus marking by cre-lox recombination revealed that a significant fraction of the virus latent in B cells had passed through a DC, and a virus attenuated for replication in DCs was impaired in B cell colonization. In vitro MuHV-4 dramatically altered the DC cytoskeleton, suggesting that it manipulates DC migration and shape in order to spread. MuHV-4 therefore uses DCs to colonize B cells.

  19. Both cladribine and alemtuzumab may effect MS via B-cell depletion.

    Science.gov (United States)

    Baker, David; Herrod, Samuel S; Alvarez-Gonzalez, Cesar; Zalewski, Lukasz; Albor, Christo; Schmierer, Klaus

    2017-07-01

    To understand the efficacy of cladribine (CLAD) treatment in MS through analysis of lymphocyte subsets collected, but not reported, in the pivotal phase III trials of cladribine and alemtuzumab induction therapies. The regulatory submissions of the CLAD Tablets Treating Multiple Sclerosis Orally (CLARITY) (NCT00213135) cladribine and Comparison of Alemtuzumab and Rebif Efficacy in Multiple Sclerosis, study one (CARE-MS I) (NCT00530348) alemtuzumab trials were obtained from the European Medicine Agency through Freedom of Information requests. Data were extracted and statistically analyzed. Either dose of cladribine (3.5 mg/kg; 5.25 mg/kg) tested in CLARITY reduced the annualized relapse rate to 0.16-0.18 over 96 weeks, and both doses were similarly effective in reducing the risk of MRI lesions and disability. Surprisingly, however, T-cell depletion was rather modest. Cladribine 3.5 mg/kg depleted CD4 + cells by 40%-45% and CD8 + cells by 15%-30%, whereas alemtuzumab suppressed CD4 + cells by 70%-95% and CD8 + cells by 47%-55%. However, either dose of cladribine induced 70%-90% CD19 + B-cell depletion, similar to alemtuzumab (90%). CD19 + cells slowly repopulated to 15%-25% of baseline before cladribine redosing. However, alemtuzumab induced hyperrepopulation of CD19 + B cells 6-12 months after infusion, which probably forms the substrate for B-cell autoimmunities associated with alemtuzumab. Cladribine induced only modest depletion of T cells, which may not be consistent with a marked influence on MS, based on previous CD4 + T-cell depletion studies. The therapeutic drug-response relationship with cladribine is more consistent with lasting B-cell depletion and, coupled with the success seen with monoclonal CD20 + depletion, suggests that B-cell suppression could be the major direct mechanism of action.

  20. Can resting B cells present antigen to T cells

    International Nuclear Information System (INIS)

    Ashwell, J.D.; DeFranco, A.L.; Paul, W.E.; Schwartz, R.H.

    1985-01-01

    Antigen stimulation of T lymphocytes can occur only in the presence of an antigen-presenting cell (APC). An ever-increasing number of cell types have been found to act as APCs; these include macrophages, splenic and lymph node dendritic cells, and Langerhans cells of the skin. Although activated B lymphocytes and B cell lymphomas are known to serve as APCs, it has been generally believed that resting B cells cannot perform this function. However, in recent studies the authors have found that resting B cells can indeed present soluble antigen to T cell clones as well as to antigen-primed T cells. The previous difficulty in demonstrating this activity can be explained by the finding that, in contrast to macrophages and dendritic cells, the antigen-presenting ability of resting B cells is very radiosensitive. Macrophages are usually irradiated with 2000-3300 rads to prevent them from incorporating [ 3 H]thymidine in the T cell proliferation assay. Resting B cells, however, begin to lose presenting function at 1500 rads and have completely lost this activity at 3300 rads. It was also possible to distinguish two distinct T cell clonal phenotypes when resting B cells were used as APCs on the basis of two different assays (T cell proliferation, and B cell proliferation resulting from T cell activation). The majority of T cell clones tested were capable of both proliferating themselves and inducing the proliferation of B cells. Some T cells clones, however, could not proliferate in the presence of antigen and B cell APCs, although they were very good at inducing the proliferation of B cells

  1. A New Immunosuppressive Molecule Emodin Induces both CD4+FoxP3+ and CD8+CD122+ Regulatory T Cells and Suppresses Murine Allograft Rejection

    Directory of Open Access Journals (Sweden)

    Feifei Qiu

    2017-11-01

    Full Text Available Due to vigorous alloimmunity, an allograft is usually rejected without any conventional immunosuppressive treatment. However, continuous global immunosuppression may cause severe side effects, including tumors and infections. Mounting evidence has shown that cyclosporine (CsA, a common immunosuppressant used in clinic, impedes allograft tolerance by dampening regulatory T cells (Tregs, although it inhibits allograft rejection at the same time. Therefore, it is necessary to seek an alternative immunosuppressive drug that spares Tregs with high efficiency in suppression but low toxicity. In this study, we investigated the capacity of emodin, an anthraquinone molecule originally extracted from certain natural plants, to prolong transplant survival in a mouse model and explored the cellular and molecular mechanisms underlying its action. We found that emodin significantly extended skin allograft survival and hindered CD3+ T cell infiltration in the allograft, accompanied by an increase in CD4+Foxp3+ and CD8+CD122+ Treg frequencies and numbers but a reduction in effector CD8+CD44highCD62Llow T cells in recipient mice. Emodin also inhibited effector CD8+ T cells proliferation in vivo. However, CD4+CD25+, but not CD8+CD122+, Tregs derived from emodin-treated recipients were more potent in suppression of allograft rejection than those isolated from control recipients, suggesting that emodin also enhances the suppressive function of CD4+CD25+ Tregs. Interestingly, depleting CD25+ Tregs largely reversed skin allograft survival prolonged by emodin while depleting CD122+ Tregs only partially abrogated the same allograft survival. Furthermore, we found that emodin hindered dendritic cell (DC maturation and reduced alloantibody production posttransplantation. Finally, we demonstrated that emodin inhibited in vitro proliferation of T cells and blocked their mTOR signaling as well. Therefore, emodin may be a novel mTOR inhibitor that suppresses alloimmunity by

  2. Phenotypic characterization of autoreactive B cells--checkpoints of B cell tolerance in patients with systemic lupus erythematosus.

    Directory of Open Access Journals (Sweden)

    Annett M Jacobi

    Full Text Available DNA-reactive B cells play a central role in systemic lupus erythematosus (SLE; DNA antibodies precede clinical disease and in established disease correlate with renal inflammation and contribute to dendritic cell activation and high levels of type 1 interferon. A number of central and peripheral B cell tolerance mechanisms designed to control the survival, differentiation and activation of autoreactive B cells are thought to be disturbed in patients with SLE. The characterization of DNA-reactive B cells has, however, been limited by their low frequency in peripheral blood. Using a tetrameric configuration of a peptide mimetope of DNA bound by pathogenic anti-DNA antibodies, we can identify B cells producing potentially pathogenic DNA-reactive antibodies. We, therefore, characterized the maturation and differentiation states of peptide, (ds double stranded DNA cross-reactive B cells in the peripheral blood of lupus patients and correlated these with clinical disease activity. Flow cytometric analysis demonstrated a significantly higher frequency of tetramer-binding B cells in SLE patients compared to healthy controls. We demonstrated the existence of a novel tolerance checkpoint at the transition of antigen-naïve to antigen-experienced. We further demonstrate that patients with moderately active disease have more autoreactive B cells in both the antigen-naïve and antigen-experienced compartments consistent with greater impairment in B cell tolerance in both early and late checkpoints in these patients than in patients with quiescent disease. This methodology enables us to gain insight into the development and fate of DNA-reactive B cells in individual patients with SLE and paves the way ultimately to permit better and more customized therapies.

  3. Comparison of EBV DNA viral load in whole blood, plasma, B-cells and B-cell culture supernatant.

    Science.gov (United States)

    Ouedraogo, David Eric; Bollore, Karine; Viljoen, Johannes; Foulongne, Vincent; Reynes, Jacques; Cartron, Guillaume; Vendrell, Jean-Pierre; Van de Perre, Philippe; Tuaillon, Edouard

    2014-05-01

    Epstein-Barr virus (EBV) genome quantitation in whole blood is used widely for therapeutic monitoring of EBV-associated disorders in immunosuppressed individuals and in patients with EBV-associated lymphoma. However, the most appropriate biological material to be used for EBV DNA quantitation remains a subject of debate. This study compare the detection rate and levels of EBV DNA from whole blood, plasma, enriched B-cells, and B-cell short-term culture supernatant using quantitative real-time PCR. Samples were collected from 33 subjects with either HIV infection or B-cell lymphoma. Overall, EBV DNA was detected in 100% of enriched B-cell samples, in 82% of B-cell culture supernatants, in 57% of plasma, and 42% of whole blood samples. A significant correlation for EBV viral load was found between enriched B-cell and B-cell culture supernatant material (ρ = 0.92; P cells (ρ = -0.02; P = 0.89), whole blood and plasma (ρ = 0.24; P = 0.24), or enriched B-cells and plasma (ρ = 0.08; P = 0.77). Testing of enriched B-cells appeared to be the most sensitive method for detection of EBV DNA as well as for exploration of the cellular reservoir. Quantitation of EBV DNA in plasma and B-cell culture supernatant may be of interest to assess EBV reactivation dynamics and response to treatment as well as to decipher EBV host-pathogen interactions in various clinical scenarios. © 2013 Wiley Periodicals, Inc.

  4. Assembly and architecture of the EBV B cell entry triggering complex.

    Directory of Open Access Journals (Sweden)

    Karthik Sathiyamoorthy

    2014-08-01

    Full Text Available Epstein-Barr Virus (EBV is an enveloped double-stranded DNA virus of the gammaherpesvirinae sub-family that predominantly infects humans through epithelial cells and B cells. Three EBV glycoproteins, gH, gL and gp42, form a complex that targets EBV infection of B cells. Human leukocyte antigen (HLA class II molecules expressed on B cells serve as the receptor for gp42, triggering membrane fusion and virus entry. The mechanistic role of gHgL in herpesvirus entry has been largely unresolved, but it is thought to regulate the activation of the virally-encoded gB protein, which acts as the primary fusogen. Here we study the assembly and function of the reconstituted B cell entry complex comprised of gHgL, gp42 and HLA class II. The structure from negative-stain electron microscopy provides a detailed snapshot of an intermediate state in EBV entry and highlights the potential for the triggering complex to bring the two membrane bilayers into proximity. Furthermore, gHgL interacts with a previously identified, functionally important hydrophobic pocket on gp42, defining the overall architecture of the complex and playing a critical role in membrane fusion activation. We propose a macroscopic model of the initiating events in EBV B cell fusion centered on the formation of the triggering complex in the context of both viral and host membranes. This model suggests how the triggering complex may bridge the two membrane bilayers, orienting critical regions of the N- and C- terminal ends of gHgL to promote the activation of gB and efficient membrane fusion.

  5. B cell antigen receptor signaling and internalization are mutually exclusive events.

    Directory of Open Access Journals (Sweden)

    Ping Hou

    2006-07-01

    Full Text Available Engagement of the B cell antigen receptor initiates two concurrent processes, signaling and receptor internalization. While both are required for normal humoral immune responses, the relationship between these two processes is unknown. Herein, we demonstrate that following receptor ligation, a small subpopulation of B cell antigen receptors are inductively phosphorylated and selectively retained at the cell surface where they can serve as scaffolds for the assembly of signaling molecules. In contrast, the larger population of non-phosphorylated receptors is rapidly endocytosed. Each receptor can undergo only one of two mutually exclusive fates because the tyrosine-based motifs that mediate signaling when phosphorylated mediate internalization when not phosphorylated. Mathematical modeling indicates that the observed competition between receptor phosphorylation and internalization enhances signaling responses to low avidity ligands.

  6. Hapten-specific naïve B cells are biomarkers of vaccine efficacy against drugs of abuse.

    Science.gov (United States)

    Taylor, J J; Laudenbach, M; Tucker, A M; Jenkins, M K; Pravetoni, M

    2014-03-01

    Vaccination against drugs of abuse shows efficacy in animal models, yet few subjects achieve effective serum antibody titers in clinical studies. A barrier to translation is the lack of pre-vaccination screening assays that predict the most effective conjugate vaccines or subjects amenable to vaccination. To address this obstacle, we developed a fluorescent antigen-based enrichment method paired with flow cytometry to characterize hapten-specific B cells. Using this approach, we studied naïve and activated B cells specific for structurally-related model haptens based on derivatization of the morphinan structure at the C6 position on oxycodone or at the C8 position on hydrocodone, and showing different pre-clinical efficacy against the prescription opioid oxycodone. Prior to vaccination, naïve B cells exhibited relatively higher affinity for the more effective C6-derivatized oxycodone-based hapten (6OXY) and the 6OXY-specific naïve B cell population contained a higher number of B cells with greater affinity for free oxycodone. Higher affinity of naïve B cells for hapten or oxycodone reflected greater efficacy of vaccination in blocking oxycodone distribution to brain in mice. Shortly after immunization, activated hapten-specific B cells were detected prior to oxycodone-specific serum antibodies and provided earlier evidence of vaccine failure or success. Analysis of hapten-specific naïve and activated B cells may aid rational vaccine design and provide screening tools to predict vaccine clinical efficacy against drugs of abuse or other small molecules. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Differential and site specific impact of B cells in the protective immune response to Mycobacterium tuberculosis in the mouse.

    Directory of Open Access Journals (Sweden)

    Egídio Torrado

    Full Text Available Cell-mediated immune responses are known to be critical for control of mycobacterial infections whereas the role of B cells and humoral immunity is unclear. B cells can modulate immune responses by secretion of immunoglobulin, production of cytokines and antigen-presentation. To define the impact of B cells in the absence of secreted immunoglobulin, we analyzed the progression of Mycobacterium tuberculosis (Mtb infection in mice that have B cells but which lack secretory immunoglobulin (AID(-/-µS(-/-mice. AID(-/-µS(-/- mice accumulated a population of activated B cells in the lungs when infected and were more susceptible to aerosol Mtb when compared to wild type (C57BL/6 mice or indeed mice that totally lack B cells. The enhanced susceptibility of AID(-/-µS(-/- mice was not associated with defective T cell activation or expression of a type 1 immune response. While delivery of normal serum to AID(-/-µS(-/- mice did not reverse susceptibility, susceptibility in the spleen was dependent upon the presence of B cells and susceptibility in the lungs of AID(-/-µS(-/-mice was associated with elevated expression of the cytokines IL-6, GM-CSF, IL-10 and molecules made by alternatively activated macrophages. Blocking of IL-10 signaling resulted in reversal of susceptibility in the spleens and lungs of AID(-/-µS(-/- mice. These data support the hypothesis that B cells can modulate immunity to Mtb in an organ specific manner via the modulation of cytokine production and macrophage activation.

  8. Invasin of Yersinia pseudotuberculosis activates human peripheral B cells.

    OpenAIRE

    Lundgren, E; Carballeira, N; Vazquez, R; Dubinina, E; Bränden, H; Persson, H; Wolf-Watz, H

    1996-01-01

    The Yersinia pseudotuberculosis cell surface-located protein invasin was found to promote binding between the pathogen and resting peripheral B cells via beta 1 integrin receptors (CD29). B cells responded by expressing several activation markers and by growing, In contrast, T cells did not react, although these cells express CD29. An isogenic invA mutant failed to activate B cells. The mutation could be complemented by providing the invA+ gene in trans. Purified invasin alone did not activat...

  9. CCR 20th anniversary commentary: Radioactive Drones for B-cell lymphoma.

    Science.gov (United States)

    Knox, Susan J; Levy, Ronald

    2015-02-01

    In a study published in the March 1, 1996, issue of Clinical Cancer Research, Knox and colleagues (1) demonstrated the safety and efficacy of Yttirium-90 ((90)Y)-anti-CD20 monoclonal antibody therapy, as well as the benefit of preinfusion of unlabeled antibody on radiolabeled antibody biodistribution. Subsequent clinical trials with this radiolabeled antibody led to regulatory approval of this treatment for B-cell lymphoma. See related article by Knox et al., Clin Cancer Res 1996;2(3) Mar 1996; 457-70. ©2015 American Association for Cancer Research.

  10. Despite disorganized synapse structure, Th2 cells maintain directional delivery of CD40L to antigen-presenting B cells.

    Science.gov (United States)

    Gardell, Jennifer L; Parker, David C

    2017-01-01

    Upon recognition of peptide displayed on MHC molecules, Th1 and Th2 cells form distinct immunological synapse structures. Th1 cells have a bull's eye synapse structure with TCR/ MHC-peptide interactions occurring central to a ring of adhesion molecules, while Th2 cells have a multifocal synapse with small clusters of TCR/MHC interactions throughout the area of T cell/antigen-presenting cell interaction. In this study, we investigated whether this structural difference in the immunological synapse affects delivery of T cell help. The immunological synapse is thought to ensure antigen-specific delivery of cytolytic granules and killing of target cells by NK cells and cytolytic T cells. In helper T cells, it has been proposed that the immunological synapse may direct delivery of other effector molecules including cytokines. CD40 ligand (CD40L) is a membrane-bound cytokine essential for antigen-specific T cell help for B cells in the antibody response. We incubated Th1 and Th2 cells overnight with a mixture of antigen-presenting and bystander B cells, and the delivery of CD40L to B cells and subsequent B cell responses were compared. Despite distinct immunological synapse structures, Th1 and Th2 cell do not differ in their ability to deliver CD40L and T cell help in an antigen-specific fashion, or in their susceptibility to inhibition of help by a blocking anti-CD40L antibody.

  11. B-Cell waste classification sampling and analysis plan

    International Nuclear Information System (INIS)

    HOBART, R.L.

    1999-01-01

    This report documents the methods used to collect and analyze samples to obtain data necessary to verify and/or determine the radionuclide content of the 324 Facility B-Cell decontamination and decommissioning waste stream

  12. IL-21: an executor of B cell fate.

    Science.gov (United States)

    Konforte, Danijela; Simard, Nathalie; Paige, Christopher J

    2009-02-15

    IL-21 is a type I cytokine that shares the common receptor gamma-chain with IL-2, IL-4, IL-7, IL-9, and IL-15. B cells are one of the lymphoid cell types whose development and function are regulated by IL-21. Depending on the interplay with costimulatory signals and on the developmental stage of a B cell, IL-21 can induce proliferation, differentiation into Ig-producing plasma cells, or apoptosis in both mice and humans. Alone and in combination with Th cell-derived cytokines IL-21 can regulate class switch recombination to IgG, IgA, or IgE isotypes, indicating its important role in shaping the effector function of B cells. This review highlights the role of IL-21 in B cell development, function, and disease and provides some perspectives on the future studies in this area.

  13. Lymphoma and the control of B cell growth and differentiation.

    Science.gov (United States)

    Rui, Lixin; Goodnow, Christopher C

    2006-05-01

    It is now widely accepted that lymphomagenesis is a multistep transformation process. A number of genetic changes and environmental and infectious factors contributing to the development and malignant progression of B-cell lymphoproliferative disorders are well documented. Reciprocal chromosomal translocations involving the immunoglobulin loci are a hallmark of most mature B cell lymphomas and lead to dysregulated expression of proto-oncogenes (c-myc) important for cell proliferation or genes involved in cell cycle progression (cyclin D1), differentiation block (bcl-6, PAX5) and cell survival (bcl-2, NF-kappaB). In addition, genetic alterations that inactivate tumor suppressor genes (p53, p16) have been frequently detected in some lymphoma tissues. Many of these genes are normally regulated by signals from the B cell antigen receptor. The high prevalence of bacterial and viral infection in lymphoma patients supports the hypothesis that infectious agents may play a contributory role in the development and evolution of B cell lymphoproliferative disorders by either directly inducing polyclonal B cell hyperactivation (EBV, HCV), or providing a chronic antigenic stimulus (EBV, HCV, HBV, H. pylori), or mimicking B cell antigen receptor signaling (EBV, HCV, HHV8), although whether these are causative factors or they are secondary to genetic changes in lymphomagenesis remains to be defined. Stimulatory signals from reactive T cells, local cytokines and growth factors can also contribute, to some extent, to the progression of transformation. Modulation of B cell antigen receptor signaling therefore emerges as a potentially powerful strategy for controlling the growth of certain B cell lymphomas.

  14. 'Big bang' of B-cell development revealed.

    Science.gov (United States)

    Murre, Cornelis

    2018-01-15

    Earlier studies have identified transcription factors that specify B-cell fate, but the underlying mechanisms remain to be revealed. Two new studies by Miyai and colleagues (pp. 112-126) and Li and colleagues (pp. 96-111) in this issue of Genes & Development provide new and unprecedented insights into the genetic and epigenetic mechanisms that establish B-cell identity. © 2018 Murre; Published by Cold Spring Harbor Laboratory Press.

  15. 324 Facility B-Cell quality process plan

    International Nuclear Information System (INIS)

    Carlson, J.L.

    1998-01-01

    This report documents the quality process plan for the restart of a hot cell in the B Plant, originally a bismuth phosphate processing facility, but later converted to a waste fractionation plant. B-Cell is currently being cleaned out and deactivated. TPA Milestone M-89-02 dictates that all mixed waste and equipment be removed from B-Cell by 5/31/1999. This report describes the major activities that remain for completion of the TPA milestone

  16. Biology and clinical application of CAR T cells for B cell malignancies.

    Science.gov (United States)

    Davila, Marco L; Sadelain, Michel

    2016-07-01

    Chimeric antigen receptor (CAR)-modified T cells have generated broad interest in oncology following a series of dramatic clinical successes in patients with chemorefractory B cell malignancies. CAR therapy now appears to be on the cusp of regulatory approval as a cell-based immunotherapy. We review here the T cell biology and cell engineering research that led to the development of second generation CARs, the selection of CD19 as a CAR target, and the preclinical studies in animal models that laid the foundation for clinical trials targeting CD19+ malignancies. We further summarize the status of CD19 CAR clinical therapy for non-Hodgkin lymphoma and B cell acute lymphoblastic leukemia, including their efficacy, toxicities (cytokine release syndrome, neurotoxicity and B cell aplasia) and current management in humans. We conclude with an overview of recent pre-clinical advances in CAR design that argues favorably for the advancement of CAR therapy to tackle other hematological malignancies as well as solid tumors.

  17. Inhibition of Ubc13-mediated Ubiquitination by GPS2 Regulates Multiple Stages of B Cell Development.

    Science.gov (United States)

    Lentucci, Claudia; Belkina, Anna C; Cederquist, Carly T; Chan, Michelle; Johnson, Holly E; Prasad, Sherry; Lopacinski, Amanda; Nikolajczyk, Barbara S; Monti, Stefano; Snyder-Cappione, Jennifer; Tanasa, Bogdan; Cardamone, M Dafne; Perissi, Valentina

    2017-02-17

    Non-proteolytic ubiquitin signaling mediated by Lys 63 ubiquitin chains plays a critical role in multiple pathways that are key to the development and activation of immune cells. Our previous work indicates that GPS2 (G-protein Pathway Suppressor 2) is a multifunctional protein regulating TNFα signaling and lipid metabolism in the adipose tissue through modulation of Lys 63 ubiquitination events. However, the full extent of GPS2-mediated regulation of ubiquitination and the underlying molecular mechanisms are unknown. Here, we report that GPS2 is required for restricting the activation of TLR and BCR signaling pathways and the AKT/FOXO1 pathway in immune cells based on direct inhibition of Ubc13 enzymatic activity. Relevance of this regulatory strategy is confirmed in vivo by B cell-targeted deletion of GPS2, resulting in developmental defects at multiple stages of B cell differentiation. Together, these findings reveal that GPS2 genomic and non-genomic functions are critical for the development and cellular homeostasis of B cells. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. B cell remote-handled waste shipment cask alternatives study; TOPICAL

    International Nuclear Information System (INIS)

    RIDDELLE, J.G.

    1999-01-01

    The decommissioning of the 324 Facility B Cell includes the onsite transport of grouted remote-handled radioactive waste from the 324 Facility to the 200 Areas for disposal. The grouted waste has been transported in the leased ATG Nuclear Services 3-82B Radioactive Waste Shipping Cask (3-82B cask). Because the 3-82B cask is a U.S. Nuclear Regulatory Commission (NRC)-certified Type B shipping cask, the lease cost is high, and the cask operations in the onsite environment may not be optimal. An alternatives study has been performed to develop cost and schedule information on alternative waste transportation systems to assist in determining which system should be used in the future. Five alternatives were identified for evaluation. These included continued lease of the 3-82B cask, fabrication of a new 3-82B cask, development and fabrication of an onsite cask, modification of the existing U.S. Department of Energy-owned cask (OH-142), and the lease of a different commercially available cask. Each alternative was compared to acceptance criteria for use in the B Cell as an initial screening. Only continued leasing of the 3-82B cask, fabrication of a new 3-82B cask, and the development and fabrication of an onsite cask were found to meet all of the B Cell acceptance criteria

  19. Origin of B-Cell Neoplasms in Autoimmune Disease.

    Directory of Open Access Journals (Sweden)

    Kari Hemminki

    Full Text Available Autoimmune diseases (ADs are associated with a number of B-cell neoplasms but the associations are selective in regard to the type of neoplasm and the conferred risks are variable. So far no mechanistic bases for these differential associations have been demonstrated. We speculate that developmental origin of B-cells might propose a mechanistic rationale for their carcinogenic response to autoimmune stimuli and tested the hypothesis on our previous studies on the risks of B-cell neoplasms after any of 33 ADs. We found that predominantly germinal center (GC-derived B-cells showed multiple associations with ADs: diffuse large B cell lymphoma associated with 15 ADs, follicular lymphoma with 7 ADs and Hodgkin lymphoma with 11 ADs. Notably, these neoplasms shared significant associations with 5 ADs (immune thrombocytopenic purpura, polymyositis/dermatomyositis, rheumatoid arthritis, Sjogren syndrome and systemic lupus erythematosis. By contrast, primarily non-GC neoplasms, acute lymphocytic leukemia, chronic lymphocytic leukemia and myeloma associated with 2 ADs only and mantle cell lymphoma with 1 AD. None of the neoplasms shared associated ADs. These data may suggest that autoimmune stimulation critically interferes with the rapid cell division, somatic hypermutation, class switch recombination and immunological selection of maturing B-cell in the GC and delivers damage contributing to transformation.

  20. Macrophage colony-stimulating factor receptor marks and regulates a fetal myeloid-primed B-cell progenitor in mice.

    Science.gov (United States)

    Zriwil, Alya; Böiers, Charlotta; Wittmann, Lilian; Green, Joanna C A; Woll, Petter S; Jacobsen, Sten Eirik W; Sitnicka, Ewa

    2016-07-14

    Although it is well established that unique B-cell lineages develop through distinct regulatory mechanisms during embryonic development, much less is understood about the differences between embryonic and adult B-cell progenitor cells, likely to underpin the genetics and biology of infant and childhood PreB acute lymphoblastic leukemia (PreB-ALL), initiated by distinct leukemia-initiating translocations during embryonic development. Herein, we establish that a distinct subset of the earliest CD19(+) B-cell progenitors emerging in the E13.5 mouse fetal liver express the colony-stimulating factor-1 receptor (CSF1R), previously thought to be expressed, and play a lineage-restricted role in development of myeloid lineages, and macrophages in particular. These early embryonic CSF1R(+)CD19(+) ProB cells also express multiple other myeloid genes and, in line with this, possess residual myeloid as well as B-cell, but not T-cell lineage potential. Notably, these CSF1R(+) myeloid-primed ProB cells are uniquely present in a narrow window of embryonic fetal liver hematopoiesis and do not persist in adult bone marrow. Moreover, analysis of CSF1R-deficient mice establishes a distinct role of CSF1R in fetal B-lymphopoiesis. CSF1R(+) myeloid-primed embryonic ProB cells are relevant for infant and childhood PreB-ALLs, which frequently have a bi-phenotypic B-myeloid phenotype, and in which CSF1R-rearrangements have recently been reported. © 2016 by The American Society of Hematology.

  1. Exposure of a distinct PDCA-1+ (CD317 B cell population to agonistic anti-4-1BB (CD137 inhibits T and B cell responses both in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Dass S Vinay

    Full Text Available 4-1BB (CD137 is an important T cell activating molecule. Here we report that it also promotes development of a distinct B cell subpopulation co-expressing PDCA-1. 4-1BB is expressed constitutively, and its expression is increased when PDCA-1(+ B cells are activated. We found that despite a high level of surface expression of 4-1BB on PDCA-1(+ B cells, treatment of these cells with agonistic anti-4-1BB mAb stimulated the expression of only a few activation markers (B7-2, MHC II, PD-L2, cytokines (IL-12p40/p70, and chemokines (MCP-1, RANTES, as well as sTNFR1, and the immunosuppressive enzyme, IDO. Although the PDCA-1(+ B cells stimulated by anti-4-1BB expressed MHC II at high levels and took up antigens efficiently, Ig class switching was inhibited when they were pulsed with T-independent (TI or T-dependent (TD Ags and adoptively transferred into syngeneic recipients. Furthermore, when anti-4-1BB-treated PDCA-1(+ B cells were pulsed with OVA peptide and combined with Vα2(+CD4(+ T cells, Ag-specific cell division was inhibited both in vitro and in vivo. Our findings suggest that the 4-1BB signal transforms PDCA-1(+ B cells into propagators of negative immune regulation, and establish an important role for 4-1BB in PDCA-1(+ B cell development and function.

  2. Endothelial Plasmalemma Vesicle Associated Protein regulates the homeostasis of splenic immature B cell and B1 B cells

    Science.gov (United States)

    Elgueta, Raul; Tse, Dan; Deharvengt, Sophie J.; Luciano, Marcus R.; Carriere, Catherine; Noelle, Randolph J.; Stan, Radu V.

    2016-01-01

    Plasmalemma vesicle associated protein (Plvap) is an endothelial protein with roles in endothelial diaphragm formation and maintenance of basal vascular permeability. At the same time Plvap has roles in immunity by facilitating leukocyte diapedesis at inflammatory sites and controlling peripheral lymph node morphogenesis and the entry of soluble antigens into lymph node conduits. Based on its postulated role in diapedesis, we have investigated the role of Plvap in hematopoiesis and show that deletion of Plvap results in a dramatic decrease of IgM+IgDlo B cells in both the spleen and peritoneal cavity. Tissue specific deletion of Plvap demonstrates that the defect is B cell extrinsic, as B cell and pan hematopoietic Plvap deletion has no effect on IgM+IgDlo B cell numbers. Endothelial specific deletion of Plvap in the embryo or at adult stage recapitulates the full Plvap knockout phenotype whereas endothelial specific reconstitution of Plvap under the Chd5 promoter rescues the IgM+IgDlo B cell phenotype. Taken together, these results show that Plvap expression in endothelial cells is important in the maintenance of IgM+ B cells in the spleen and peritoneal cavity. PMID:27742829

  3. Endothelial Plasmalemma Vesicle-Associated Protein Regulates the Homeostasis of Splenic Immature B Cells and B-1 B Cells.

    Science.gov (United States)

    Elgueta, Raul; Tse, Dan; Deharvengt, Sophie J; Luciano, Marcus R; Carriere, Catherine; Noelle, Randolph J; Stan, Radu V

    2016-11-15

    Plasmalemma vesicle-associated protein (Plvap) is an endothelial protein with roles in endothelial diaphragm formation and maintenance of basal vascular permeability. At the same time, Plvap has roles in immunity by facilitating leukocyte diapedesis at inflammatory sites and controlling peripheral lymph node morphogenesis and the entry of soluble Ags into lymph node conduits. Based on its postulated role in diapedesis, we have investigated the role of Plvap in hematopoiesis and show that deletion of Plvap results in a dramatic decrease of IgM + IgD lo B cells in both the spleen and the peritoneal cavity. Tissue-specific deletion of Plvap demonstrates that the defect is B cell extrinsic, because B cell and pan-hematopoietic Plvap deletion has no effect on IgM + IgD lo B cell numbers. Endothelial-specific deletion of Plvap in the embryo or at adult stage recapitulates the full Plvap knockout phenotype, whereas endothelial-specific reconstitution of Plvap under the Chd5 promoter rescues the IgM + IgD lo B cell phenotype. Taken together, these results show that Plvap expression in endothelial cells is important in the maintenance of IgM + B cells in the spleen and peritoneal cavity. Copyright © 2016 by The American Association of Immunologists, Inc.

  4. The role of the interleukin-10 subfamily members in immunoglobulin production by human B cells

    DEFF Research Database (Denmark)

    Hummelshoj, L; Ryder, L P; Poulsen, Lars K.

    2006-01-01

    Interleukin (IL)-10 has been shown to have various effects on B cells, including positively affecting the production of immunoglobulin A (IgA) and IgG. Several human IL-10-related molecules have been identified. These include IL-19, IL-20, IL-22, IL-24, IL-26, IL-28 and IL-29. To determine...... the effects of the IL-10 analogues on the class switch recombination in B cells, we analysed Ig production from naïve B cells stimulated with these cytokines in the presence of anti-CD40. None of the cytokines were found to induce Ig production by themselves in the presence of anti-CD40 Ab. However, all...... cytokines inhibited the production of IgA and IgG induced by anti-CD40 Ab alone. In combination with anti-CD40 Ab and IL-4, IgG4 were inhibited in cultures stimulated with IL-20, IL-22, IL-26, IL-28 and IL-29 compared with IL-4 and anti-CD40 Ab alone, whereas all IL-10 analogues increased the production...

  5. Tolerogenic CX3CR1+ B cells suppress food allergy-induced intestinal inflammation in mice.

    Science.gov (United States)

    Liu, Z Q; Wu, Y; Song, J P; Liu, X; Liu, Z; Zheng, P Y; Yang, P C

    2013-10-01

    B lymphocytes are an important cell population of the immune regulation; their role in the regulation of food allergy has not been fully understood yet. This study aims to investigate the role of a subpopulation of tolerogenic B cells (TolBC) in the generation of regulatory T cells (Treg) and in the suppression of food allergy-induced intestinal inflammation in mice. The intestinal mucosa-derived CD5+ CD19+ CX3CR1+ TolBCs were characterized by flow cytometry; a mouse model of intestinal T helper (Th)2 inflammation was established to assess the immune regulatory role of this subpopulation of TolBCs. A subpopulation of CD5+ CD19+ CX3CR1+ B cells was detected in the mouse intestinal mucosa. The cells also expressed transforming growth factor (TGF)-β and carried integrin alpha v beta 6 (αvβ6). Exposure to recombinant αvβ6 and anti-IgM antibody induced naive B cells to differentiate into the TGF-β-producing TolBCs. Coculturing this subpopulation of TolBCs with Th0 cells generated CD4+ CD25+ Foxp3+ Tregs. Adoptive transfer with the TolBCs markedly suppressed the food allergy-induced intestinal Th2 pattern inflammation in mice. CD5+ CD19+ CX3CR1+ TolBCs are capable of inducing Tregs in the intestine and suppress food allergy-related Th2 pattern inflammation in mice. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. TIM-1 signaling in B cells regulates antibody production

    International Nuclear Information System (INIS)

    Ma, Juan; Usui, Yoshihiko; Takeda, Kazuyoshi; Harada, Norihiro; Yagita, Hideo; Okumura, Ko; Akiba, Hisaya

    2011-01-01

    Highlights: → TIM-1 is highly expressed on anti-IgM + anti-CD40-stimulated B cells. → Anti-TIM-1 mAb enhanced proliferation and Ig production on activated B cell in vitro. → TIM-1 signaling regulates Ab production by response to TI-2 and TD antigens in vivo. -- Abstract: Members of the T cell Ig and mucin (TIM) family have recently been implicated in the control of T cell-mediated immune responses. In this study, we found TIM-1 expression on anti-IgM- or anti-CD40-stimulated splenic B cells, which was further up-regulated by the combination of anti-IgM and anti-CD40 Abs. On the other hand, TIM-1 ligand was constitutively expressed on B cells and inducible on anti-CD3 + anti-CD28-stimulated CD4 + T cells. In vitro stimulation of activated B cells by anti-TIM-1 mAb enhanced proliferation and expression of a plasma cell marker syndecan-1 (CD138). We further examined the effect of TIM-1 signaling on antibody production in vitro and in vivo. Higher levels of IgG2b and IgG3 secretion were detected in the culture supernatants of the anti-TIM-1-stimulated B cells as compared with the control IgG-stimulated B cells. When immunized with T-independent antigen TNP-Ficoll, TNP-specific IgG1, IgG2b, and IgG3 Abs were slightly increased in the anti-TIM-1-treated mice. When immunized with T-dependent antigen OVA, serum levels of OVA-specific IgG2b, IgG3, and IgE Abs were significantly increased in the anti-TIM-1-treated mice as compared with the control IgG-treated mice. These results suggest that TIM-1 signaling in B cells augments antibody production by enhancing B cell proliferation and differentiation.

  7. TIM-1 signaling in B cells regulates antibody production

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Juan [Department of Immunology, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421 (Japan); Usui, Yoshihiko [Department of Immunology, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421 (Japan); Department of Ophthalmology, Tokyo Medical University, 6-7-1 Nishi-shinjuku-ku, Tokyo 160-0023 (Japan); Takeda, Kazuyoshi [Department of Immunology, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421 (Japan); Harada, Norihiro [Department of Immunology, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421 (Japan); Department of Respiratory Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421 (Japan); Research Institute for Diseases of Old Ages, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421 (Japan); Yagita, Hideo; Okumura, Ko [Department of Immunology, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421 (Japan); Akiba, Hisaya, E-mail: hisaya@juntendo.ac.jp [Department of Immunology, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421 (Japan)

    2011-03-11

    Highlights: {yields} TIM-1 is highly expressed on anti-IgM + anti-CD40-stimulated B cells. {yields} Anti-TIM-1 mAb enhanced proliferation and Ig production on activated B cell in vitro. {yields} TIM-1 signaling regulates Ab production by response to TI-2 and TD antigens in vivo. -- Abstract: Members of the T cell Ig and mucin (TIM) family have recently been implicated in the control of T cell-mediated immune responses. In this study, we found TIM-1 expression on anti-IgM- or anti-CD40-stimulated splenic B cells, which was further up-regulated by the combination of anti-IgM and anti-CD40 Abs. On the other hand, TIM-1 ligand was constitutively expressed on B cells and inducible on anti-CD3{sup +} anti-CD28-stimulated CD4{sup +} T cells. In vitro stimulation of activated B cells by anti-TIM-1 mAb enhanced proliferation and expression of a plasma cell marker syndecan-1 (CD138). We further examined the effect of TIM-1 signaling on antibody production in vitro and in vivo. Higher levels of IgG2b and IgG3 secretion were detected in the culture supernatants of the anti-TIM-1-stimulated B cells as compared with the control IgG-stimulated B cells. When immunized with T-independent antigen TNP-Ficoll, TNP-specific IgG1, IgG2b, and IgG3 Abs were slightly increased in the anti-TIM-1-treated mice. When immunized with T-dependent antigen OVA, serum levels of OVA-specific IgG2b, IgG3, and IgE Abs were significantly increased in the anti-TIM-1-treated mice as compared with the control IgG-treated mice. These results suggest that TIM-1 signaling in B cells augments antibody production by enhancing B cell proliferation and differentiation.

  8. Altered distribution of peripheral blood memory B cells in humans chronically infected with Trypanosoma cruzi.

    Science.gov (United States)

    Fernández, Esteban R; Olivera, Gabriela C; Quebrada Palacio, Luz P; González, Mariela N; Hernandez-Vasquez, Yolanda; Sirena, Natalia María; Morán, María L; Ledesma Patiño, Oscar S; Postan, Miriam

    2014-01-01

    Numerous abnormalities of the peripheral blood T cell compartment have been reported in human chronic Trypanosoma cruzi infection and related to prolonged antigenic stimulation by persisting parasites. Herein, we measured circulating lymphocytes of various phenotypes based on the differential expression of CD19, CD4, CD27, CD10, IgD, IgM, IgG and CD138 in a total of 48 T. cruzi-infected individuals and 24 healthy controls. Infected individuals had decreased frequencies of CD19+CD27+ cells, which positively correlated with the frequencies of CD4+CD27+ cells. The contraction of CD19+CD27+ cells was comprised of IgG+IgD-, IgM+IgD- and isotype switched IgM-IgD- memory B cells, CD19+CD10+CD27+ B cell precursors and terminally differentiated CD19+CD27+CD138+ plasma cells. Conversely, infected individuals had increased proportions of CD19+IgG+CD27-IgD- memory and CD19+IgM+CD27-IgD+ transitional/naïve B cells. These observations prompted us to assess soluble CD27, a molecule generated by the cleavage of membrane-bound CD27 and used to monitor systemic immune activation. Elevated levels of serum soluble CD27 were observed in infected individuals with Chagas cardiomyopathy, indicating its potentiality as an immunological marker for disease progression in endemic areas. In conclusion, our results demonstrate that chronic T. cruzi infection alters the distribution of various peripheral blood B cell subsets, probably related to the CD4+ T cell deregulation process provoked by the parasite in humans.

  9. Altered distribution of peripheral blood memory B cells in humans chronically infected with Trypanosoma cruzi.

    Directory of Open Access Journals (Sweden)

    Esteban R Fernández

    Full Text Available Numerous abnormalities of the peripheral blood T cell compartment have been reported in human chronic Trypanosoma cruzi infection and related to prolonged antigenic stimulation by persisting parasites. Herein, we measured circulating lymphocytes of various phenotypes based on the differential expression of CD19, CD4, CD27, CD10, IgD, IgM, IgG and CD138 in a total of 48 T. cruzi-infected individuals and 24 healthy controls. Infected individuals had decreased frequencies of CD19+CD27+ cells, which positively correlated with the frequencies of CD4+CD27+ cells. The contraction of CD19+CD27+ cells was comprised of IgG+IgD-, IgM+IgD- and isotype switched IgM-IgD- memory B cells, CD19+CD10+CD27+ B cell precursors and terminally differentiated CD19+CD27+CD138+ plasma cells. Conversely, infected individuals had increased proportions of CD19+IgG+CD27-IgD- memory and CD19+IgM+CD27-IgD+ transitional/naïve B cells. These observations prompted us to assess soluble CD27, a molecule generated by the cleavage of membrane-bound CD27 and used to monitor systemic immune activation. Elevated levels of serum soluble CD27 were observed in infected individuals with Chagas cardiomyopathy, indicating its potentiality as an immunological marker for disease progression in endemic areas. In conclusion, our results demonstrate that chronic T. cruzi infection alters the distribution of various peripheral blood B cell subsets, probably related to the CD4+ T cell deregulation process provoked by the parasite in humans.

  10. Susceptibility of Hep3B cells in different phases of cell cycle to tBid.

    Science.gov (United States)

    Ma, Shi-Hong; Chen, George G; Ye, Caiguo; Leung, Billy C S; Ho, Rocky L K; Lai, Paul B S

    2011-01-01

    tBid is a pro-apoptotic molecule. Apoptosis inducers usually act in a cell cycle-specific fashion. The aim of this study was to elucidate whether effect of tBid on hepatocellular carcinoma (HCC) Hep3B cells was cell cycle phase specific. We synchronized Hep3B cells at G0/G1, S or G2/M phases by chemicals or flow sorting and tested the susceptibility of the cells to recombinant tBid. Cell viability was measured by MTT assay and apoptosis by TUNEL. The results revealed that tBid primarily targeted the cells at G0/G1 phase of cell cycle, and it also increased the cells at the G2/M phase. 5-Fluorouracil (5-FU), on the other hand, arrested Hep3B cells at the G0/G1 phase, but significantly reduced cells at G2/M phase. The levels of cell cycle-related proteins and caspases were altered in line with the change in the cell cycle. The combination of tBid with 5-FU caused more cells to be apoptotic than either agent alone. Therefore, the complementary effect of tBid and 5-FU on different phases of the cell cycle may explain their synergistric effect on Hep3B cells. The elucidation of the phase-specific effect of tBid points to a possible therapeutic option that combines different phase specific agents to overcome resistance of HCC. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Myeloid-derived suppressor cells in murine AIDS inhibit B-cell responses in part via soluble mediators including reactive oxygen and nitrogen species, and TGF-β

    Energy Technology Data Exchange (ETDEWEB)

    Rastad, Jessica L. [Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756 (United States); Green, William R., E-mail: William.R.Green@dartmouth.edu [Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756 (United States); Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756 (United States)

    2016-12-15

    Monocytic myeloid-derived suppressor cells (M-MDSCs) were increased during LP-BM5 retroviral infection, and were capable of suppressing not only T-cell, but also B-cell responses. In addition to previously demonstrating iNOS- and VISTA-dependent M-MDSC mechanisms, in this paper, we detail how M-MDSCs utilized soluble mediators, including the reactive oxygen and nitrogen species superoxide, peroxynitrite, and nitric oxide, and TGF-β, to suppress B cells in a predominantly contact-independent manner. Suppression was independent of cysteine-depletion and hydrogen peroxide production. When two major mechanisms of suppression (iNOS and VISTA) were eliminated in double knockout mice, M-MDSCs from LP-BM5-infected mice were able to compensate using other, soluble mechanisms in order to maintain suppression of B cells. The IL-10 producing regulatory B-cell compartment was among the targets of M-MDSC-mediated suppression. -- Highlights: •LP-BM5-expanded M-MDSCs utilized soluble mediators nitric oxide, superoxide, peroxynitrite, and TGF-β to suppress B cells. •When two major mechanisms of suppression were eliminated through knockouts, M-MDSCs maintained suppression. •M-MDSCs from LP-BM5-infected mice decreased proliferation of IL-10 producing regulatory B cells.

  12. Myeloid-derived suppressor cells in murine AIDS inhibit B-cell responses in part via soluble mediators including reactive oxygen and nitrogen species, and TGF-β

    International Nuclear Information System (INIS)

    Rastad, Jessica L.; Green, William R.

    2016-01-01

    Monocytic myeloid-derived suppressor cells (M-MDSCs) were increased during LP-BM5 retroviral infection, and were capable of suppressing not only T-cell, but also B-cell responses. In addition to previously demonstrating iNOS- and VISTA-dependent M-MDSC mechanisms, in this paper, we detail how M-MDSCs utilized soluble mediators, including the reactive oxygen and nitrogen species superoxide, peroxynitrite, and nitric oxide, and TGF-β, to suppress B cells in a predominantly contact-independent manner. Suppression was independent of cysteine-depletion and hydrogen peroxide production. When two major mechanisms of suppression (iNOS and VISTA) were eliminated in double knockout mice, M-MDSCs from LP-BM5-infected mice were able to compensate using other, soluble mechanisms in order to maintain suppression of B cells. The IL-10 producing regulatory B-cell compartment was among the targets of M-MDSC-mediated suppression. -- Highlights: •LP-BM5-expanded M-MDSCs utilized soluble mediators nitric oxide, superoxide, peroxynitrite, and TGF-β to suppress B cells. •When two major mechanisms of suppression were eliminated through knockouts, M-MDSCs maintained suppression. •M-MDSCs from LP-BM5-infected mice decreased proliferation of IL-10 producing regulatory B cells.

  13. Microenvironment-Centred Dynamics in Aggressive B-Cell Lymphomas

    Directory of Open Access Journals (Sweden)

    Matilde Cacciatore

    2012-01-01

    Full Text Available Aggressive B-cell lymphomas share high proliferative and invasive attitudes and dismal prognosis despite heterogeneous biological features. In the interchained sequence of events leading to cancer progression, neoplastic clone-intrinsic molecular events play a major role. Nevertheless, microenvironment-related cues have progressively come into focus as true determinants for this process. The cancer-associated microenvironment is a complex network of nonneoplastic immune and stromal cells embedded in extracellular components, giving rise to a multifarious crosstalk with neoplastic cells towards the induction of a supportive milieu. The immunological and stromal microenvironments have been classically regarded as essential partners of indolent lymphomas, while considered mainly negligible in the setting of aggressive B-cell lymphomas that, by their nature, are less reliant on external stimuli. By this paper we try to delineate the cardinal microenvironment-centred dynamics exerting an influence over lymphoid clone progression in aggressive B-cell lymphomas.

  14. The acquisition of cytokine responsiveness by murine B cells

    DEFF Research Database (Denmark)

    Poudrier, J; Owens, T

    1994-01-01

    chains and mRNA to levels comparable to those seen in activated T cells. Anti-mu-stimulated B cells responded to IL-2 by incorporation of [3H]thymidine and high rate immunoglobulin (Ig) secretion. Both IL-5 (at optimal concentration) and suboptimal lipopolysaccharide (LPS; 20 ng/ml) induced surface...... expression of IL-2R alpha. The level of expression induced by IL-5 was equivalent to that on anti-Ig-activated B cells. Neither stimulus induced detectable expression of IL-2R beta, and neither induced B cells to respond to IL-2. IL-2R alpha expression was strongly enhanced, and low levels of IL-2R beta...

  15. Effect of antigen on localization of immunologically specific B cells

    International Nuclear Information System (INIS)

    Ponzio, N.M.; Chapman, J.M.; Thorbecke, G.J.

    1976-01-01

    Studies were conducted to demonstrate homing of memory B cells to sites of antigen localization in lymph nodes, using functional criteria to detect local presence of memory cells at varying intervals after intravenous injection. Cell suspensions were prepared from spleens of donor mice injected with complete Freund's adjuvant. Recipient mice were injected with Escherichia coli endotoxin and immune or normal spleen cells and were gamma-irradiated. Results indicated that passively transferred unilateral B cell memory was established. The development over a period of several days of this difference between left and right lymph nodes suggests that recirculating memory B cells are being progressively selected by antigen in the lymph node, rather than that this difference is due to a specific exit of cells from the circulation towards the antigen

  16. A rare cause of ischemic stroke: Intravasculer B cell lymphoma

    Directory of Open Access Journals (Sweden)

    Şeyma Çiftçi

    2014-08-01

    Full Text Available Intravascular B cell lymphoma is rare and an agressive form of large B cell lymphoma which can affect central nervous system. Because of its varied clinical symptoms and the absence of lymphadenopathy, it is generally diagnosed postmortem. Cerebral infarction due to occlusion of arteries can be seen as a rare clinical form of central nervous system involvement. Large artery atherosclerosis, cardiyoembolism and small artery occlusion are the important causes of ischemic stroke but no any cause is detected in %15-40 of all cases. In this report, with the discussion of a case with ischemia like encephalopathy and multiple cerebral ischemic lesions at different stages in cranial MRI which was diagnosed by the help of brain biopsy as a intravascular B cell lymphoma, it is aimed to take attention intravascular lymphoma as a rare cause of ischemic stroke.

  17. IgM and IgD B cell receptors differentially respond to endogenous antigens and control B cell fate

    Science.gov (United States)

    Noviski, Mark; Mueller, James L; Satterthwaite, Anne; Garrett-Sinha, Lee Ann; Brombacher, Frank

    2018-01-01

    Naive B cells co-express two BCR isotypes, IgM and IgD, with identical antigen-binding domains but distinct constant regions. IgM but not IgD is downregulated on autoreactive B cells. Because these isotypes are presumed to be redundant, it is unknown how this could impose tolerance. We introduced the Nur77-eGFP reporter of BCR signaling into mice that express each BCR isotype alone. Despite signaling strongly in vitro, IgD is less sensitive than IgM to endogenous antigen in vivo and developmental fate decisions are skewed accordingly. IgD-only Lyn−/− B cells cannot generate autoantibodies and short-lived plasma cells (SLPCs) in vivo, a fate thought to be driven by intense BCR signaling induced by endogenous antigens. Similarly, IgD-only B cells generate normal germinal center, but impaired IgG1+ SLPC responses to T-dependent immunization. We propose a role for IgD in maintaining the quiescence of autoreactive B cells and restricting their differentiation into autoantibody secreting cells. PMID:29521626

  18. Understanding B-cell activation and autoantibody repertoire selection in systemic lupus erythematosus: A B-cell immunomics approach.

    Science.gov (United States)

    Tipton, Christopher M; Hom, Jennifer R; Fucile, Christopher F; Rosenberg, Alexander F; Sanz, Inaki

    2018-07-01

    Understanding antibody repertoires and in particular, the properties and fates of B cells expressing potentially pathogenic antibodies is critical to define the mechanisms underlying multiple immunological diseases including autoimmune and allergic conditions as well as transplant rejection. Moreover, an integrated knowledge of the antibody repertoires expressed by B cells and plasma cells (PC) of different functional properties and longevity is essential to develop new therapeutic strategies, better biomarkers for disease segmentation, and new assays to measure restoration of B-cell tolerance or, at least, of normal B-cell homeostasis. Reaching these goals, however, will require a more precise phenotypic, functional and molecular definition of B-cell and PC populations, and a comprehensive analysis of the antigenic reactivity of the antibodies they express. While traditionally hampered by technical and ethical limitations in human experimentation, new technological advances currently enable investigators to address these questions in a comprehensive fashion. In this review, we shall discuss these concepts as they apply to the study of Systemic Lupus Erythematosus. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Reprogramming of B cells into macrophages: mechanistic insights

    OpenAIRE

    Di Tullio, Alessandro, 1982-

    2012-01-01

    Our earlier work has shown that pre-B cells can be converted into macrophages by the transcription factor C/EBPα at very high frequencies and also that a clonal pre-B cell line with an inducible form of C/EBPα can be converted into macrophage-like cells. Using these systems we have performed a systematic analysis of the questions whether during transdifferentiation the cells retrodifferentiate to a precursor cell state and whether cell cycle is required for reprogramming. As for the first ...

  20. Epigenetics of peripheral B cell differentiation and the antibody response

    Directory of Open Access Journals (Sweden)

    Hong eZan

    2015-12-01

    Full Text Available Epigenetic modifications, such as histone post-translational modifications, DNA methylation, and alteration of gene expression by non-coding RNAs, including microRNAs (miRNAs and long non-coding RNAs (lncRNAs, are heritable changes that are independent from the genomic DNA sequence. These regulate gene activities and, therefore, cellular functions. Epigenetic modifications act in concert with transcription factors and play critical roles in B cell development and differentiation, thereby modulating antibody responses to foreign- and self-antigens. Upon antigen encounter by mature B cells in the periphery, alterations of these lymphocytes epigenetic landscape are induced by the same stimuli that drive the antibody response. Such alterations instruct B cells to undergo immunoglobulin class switch DNA recombination (CSR and somatic hypermutation (SHM, as well as differentiation to memory B cells or long-lived plasma cells for the immune memory. Inducible histone modifications, together with DNA methylation and miRNAs modulate the transcriptome, particularly the expression of activation-induced cytidine deaminase (AID, which is essential for CSR and SHM, and factors central to plasma cell differentiation, such as B lymphocyte-induced maturation protein-1 (Blimp-1. These inducible B cell-intrinsic epigenetic marks guide the maturation of antibody responses. Combinatorial histone modifications also function as histone codes to target CSR and, possibly, SHM machinery to the Ig loci by recruiting specific adaptors that can stabilize CSR/SHM factors. In addition, lncRNAs, such as recently reported lncRNA-CSR and an lncRNA generated through transcription of the S region that form G-quadruplex structures, are also important for CSR targeting. Epigenetic dysregulation in B cells, including the aberrant expression of non-coding RNAs and alterations of histone modifications and DNA methylation, can result in aberrant antibody responses to foreign antigens

  1. Immunomodulating effects of heparin on human B cell proliferation

    International Nuclear Information System (INIS)

    Wasik, Maria; Stepien-Sopniewska, Barbara; Gorski, Andrzej

    1993-01-01

    Recent data indicate that heparin may act as an immunomodulator. In this paper we have analyzed the effect of this agent on human B cell proliferation ''in vitro'' induced by ''S. aureus'' Cowan. The action of heparin is complex, but there was a trend for inhibition of B cell responses obtained from defibrinated but not heparinized blood samples. This suggest that heparin interacts with platelet products (growth factors, cytokines) and the results of such interactions determine the final effect. (author). 6 refs, 4 figs

  2. CD4+ T cell-mediated cytotoxicity is associated with MHC class II expression on malignant CD19+ B cells in diffuse large B cell lymphoma.

    Science.gov (United States)

    Zhou, Yong; Zha, Jie; Lin, Zhijuan; Fang, Zhihong; Zeng, Hanyan; Zhao, Jintao; Luo, Yiming; Li, Zhifeng; Xu, Bing

    2018-01-15

    Diffuse large B cell lymphoma (DLBCL) is a common B cell malignancy with approximately 30% of patients present relapsed or refractory disease after first-line therapy. Research of further treatment options is needed. Cytotoxic CD4 + T cells express cytolytic molecules and have potential antitumor function. Here, we showed that the CD19 + cells from DLBCL patients presented significantly reduced expression of MHC II molecules than those from healthy controls. Three years after the first-line treatment, patients that presented relapsed disease had significantly lower MHC II expression on their CD19 + cells than patients who did not show recurrence. Examining cytotoxic CD4 + T cells show that DLBCL patients presented significantly elevated frequencies of granzyme A-, granzyme B-, and/or perforin-expressing cytotoxic CD4 + T cells. Also, frequency of cytotoxic CD4 + T cells in DLBCL patients was positively correlated with the MHC II expression level. Subsequently, the cytotoxic potential of CD4 + T cells against autologous CD19 + cells was investigated. We found that the cytotoxic potential of CD4 + T cells was highest in MHC II-high, intermediate in MHC II-mid, and lowest in MHC II-low patients. The percentage of MHC II-expressing viable CD19 + cells presented a significant reduction after longer incubation with cytotoxic CD4 + T cells, suggesting that cytotoxic CD4 + T cells preferentially eliminated MHC II-expressing CD19 + cells. Blocking MHC II on CD19 + cells significantly reduced the cytolytic capacity of CD4 + T cells. Despite these discoveries, the frequency of cytotoxic CD4 + T cells did not predict the clinical outcome of DLBCL patients. Together, these results demonstrated that cytotoxic CD4 + T cells presented an MHC II-dependent cytotoxic potential against autologous CD19 + cells and could potentially represent a future treatment option for DLBCL. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Homeobox NKX2-3 promotes marginal-zone lymphomagenesis by activating B-cell receptor signalling and shaping lymphocyte dynamics

    Science.gov (United States)

    Robles, Eloy F.; Mena-Varas, Maria; Barrio, Laura; Merino-Cortes, Sara V.; Balogh, Péter; Du, Ming-Qing; Akasaka, Takashi; Parker, Anton; Roa, Sergio; Panizo, Carlos; Martin-Guerrero, Idoia; Siebert, Reiner; Segura, Victor; Agirre, Xabier; Macri-Pellizeri, Laura; Aldaz, Beatriz; Vilas-Zornoza, Amaia; Zhang, Shaowei; Moody, Sarah; Calasanz, Maria Jose; Tousseyn, Thomas; Broccardo, Cyril; Brousset, Pierre; Campos-Sanchez, Elena; Cobaleda, Cesar; Sanchez-Garcia, Isidro; Fernandez-Luna, Jose Luis; Garcia-Muñoz, Ricardo; Pena, Esther; Bellosillo, Beatriz; Salar, Antonio; Baptista, Maria Joao; Hernandez-Rivas, Jesús Maria; Gonzalez, Marcos; Terol, Maria Jose; Climent, Joan; Ferrandez, Antonio; Sagaert, Xavier; Melnick, Ari M.; Prosper, Felipe; Oscier, David G.; Carrasco, Yolanda R.; Dyer, Martin J. S.; Martinez-Climent, Jose A.

    2016-01-01

    NKX2 homeobox family proteins have a role in cancer development. Here we show that NKX2-3 is overexpressed in tumour cells from a subset of patients with marginal-zone lymphomas, but not with other B-cell malignancies. While Nkx2-3-deficient mice exhibit the absence of marginal-zone B cells, transgenic mice with expression of NKX2-3 in B cells show marginal-zone expansion that leads to the development of tumours, faithfully recapitulating the principal clinical and biological features of human marginal-zone lymphomas. NKX2-3 induces B-cell receptor signalling by phosphorylating Lyn/Syk kinases, which in turn activate multiple integrins (LFA-1, VLA-4), adhesion molecules (ICAM-1, MadCAM-1) and the chemokine receptor CXCR4. These molecules enhance migration, polarization and homing of B cells to splenic and extranodal tissues, eventually driving malignant transformation through triggering NF-κB and PI3K-AKT pathways. This study implicates oncogenic NKX2-3 in lymphomagenesis, and provides a valid experimental mouse model for studying the biology and therapy of human marginal-zone B-cell lymphomas. PMID:27297662

  4. Anti-HIV-1 B cell responses are dependent on B cell precursor frequency and antigen-binding affinity.

    Science.gov (United States)

    Dosenovic, Pia; Kara, Ervin E; Pettersson, Anna-Klara; McGuire, Andrew T; Gray, Matthew; Hartweger, Harald; Thientosapol, Eddy S; Stamatatos, Leonidas; Nussenzweig, Michel C

    2018-04-16

    The discovery that humans can produce potent broadly neutralizing antibodies (bNAbs) to several different epitopes on the HIV-1 spike has reinvigorated efforts to develop an antibody-based HIV-1 vaccine. Antibody cloning from single cells revealed that nearly all bNAbs show unusual features that could help explain why it has not been possible to elicit them by traditional vaccination and instead would require a sequence of different immunogens. This idea is supported by experiments with genetically modified immunoglobulin (Ig) knock-in mice. Sequential immunization with a series of specifically designed immunogens was required to shepherd the development of bNAbs. However, knock-in mice contain superphysiologic numbers of bNAb precursor-expressing B cells, and therefore how these results can be translated to a more physiologic setting remains to be determined. Here we make use of adoptive transfer experiments using knock-in B cells that carry a synthetic intermediate in the pathway to anti-HIV-1 bNAb development to examine how the relationship between B cell receptor affinity and precursor frequency affects germinal center (GC) B cell recruitment and clonal expansion. Immunization with soluble HIV-1 antigens can recruit bNAb precursor B cells to the GC when there are as few as 10 such cells per mouse. However, at low precursor frequencies, the extent of clonal expansion is directly proportional to the affinity of the antigen for the B cell receptor, and recruitment to GCs is variable and dependent on recirculation.

  5. 324 Facility B-Cell quality process plan

    International Nuclear Information System (INIS)

    Carlson, J.L.

    1998-01-01

    B-Cell is currently being cleaned out (i.e., removal of equipment, fixtures and residual radioactive materials) and deactivated. TPA Milestone M-89-02 dictates that all mixed waste and equipment be removed from B-Cell by 5/31/99. The following sections describe the major activities that remain for completion of the TPA milestone. This includes: (1) Size Reduce Tank 119 and Miscellaneous Equipment. This activity is the restart of hotwork in B-Cell to size reduce the remainder of Tank 119 and other miscellaneous pieces of equipment into sizes that can be loaded into a grout container. This activity also includes the process of preparing the containers for shipment from the cell. The specific activities and procedures used are detailed in a table. (2) Load and Ship Low-Level Waste. This activity covers the process of taking a grouted LLW container from B-Cell and loading it into the cask in the REC airlock and Cask Handling Area (CHA) for shipment to the LLBG. The detailed activities and procedures for this part of cell cleanout are included in second table

  6. Targeting the BCR signalosome in B cell malignancies

    NARCIS (Netherlands)

    de Rooij, M.F.M.

    2017-01-01

    Chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), and Waldenström macroglobulinemia (WM) are B-cell malignancies which are still incurable. In these lymphomas, the cells proliferate in specialized niches in lymph nodes and bone marrow, in which they are provided by stromal-derived

  7. [Ibrutinib: A new drug of B-cell malignancies].

    Science.gov (United States)

    Thieblemont, Catherine

    2015-06-01

    Ibrutinib (Imbruvica®) is a first-in-class, orally administered once-daily, that inhibits B-cell antigen receptor signaling downstream of Bruton's tyrosine kinase (BTK). Ibrutinib has been approved in USA in February 2014 and in France in October 2014 for the treatment of patients with relapsed/refractory mantle cell lymphoma (MCL) or chronic lymphocytic leukaemia (CLL) and for the treatment of patients with CLL and a chromosome 17 deletion (del 17p) or TP53 mutation. In clinical studies, ibrutinib induced an impressive overall response rate (68%) in patients with relapsed/refractory MCL (phase II study). In CLL, ibrutinib has shown to significantly improve progression-free survival, response rate and overall survival in patients with relapsed/refractory CLL, including in those with del 17p. Ibrutinib had an acceptable tolerability profile. Less than 10% of patients discontinued their treatment because of adverse events. Results are pending in other B-cell lymphomas subtypes such as in diffuse large B-cell lymphoma and in follicular lymphoma. An approval extension has already been enregistered for Waldenström disease in USA in January 2015. Given its efficacy and tolerability, ibrutinib is an emerging treatment option for patients with B-cell malignancies. Copyright © 2015 Société Françise du Cancer. Publié par Elsevier Masson SAS. Tous droits réservés. Published by Elsevier Masson SAS. All rights reserved.

  8. Role of Bruton's tyrosine kinase in B cells and malignancies

    NARCIS (Netherlands)

    Pal Singh, S. (Simar); F. Dammeijer (Floris); R.W. Hendriks (Rudi)

    2018-01-01

    textabstractBruton's tyrosine kinase (BTK) is a non-receptor kinase that plays a crucial role in oncogenic signaling that is critical for proliferation and survival of leukemic cells in many B cell malignancies. BTK was initially shown to be defective in the primary immunodeficiency X-linked

  9. Profiling of diffuse large B-cell lymphoma by immunohistochemistry

    DEFF Research Database (Denmark)

    Sjö, Lene Dissing; Poulsen, Christian Bjørn; Hansen, Mads

    2007-01-01

    Diffuse large B-cell lymphoma (DLBCL) is a frequent lymphoma subtype with a heterogeneous behavior and a variable response to conventional chemotherapy. This clinical diversity is believed to reflect differences in the molecular pathways leading to lymphomagenesis. In this study, we have analyzed...

  10. Likelihood-Based Inference of B Cell Clonal Families.

    Directory of Open Access Journals (Sweden)

    Duncan K Ralph

    2016-10-01

    Full Text Available The human immune system depends on a highly diverse collection of antibody-making B cells. B cell receptor sequence diversity is generated by a random recombination process called "rearrangement" forming progenitor B cells, then a Darwinian process of lineage diversification and selection called "affinity maturation." The resulting receptors can be sequenced in high throughput for research and diagnostics. Such a collection of sequences contains a mixture of various lineages, each of which may be quite numerous, or may consist of only a single member. As a step to understanding the process and result of this diversification, one may wish to reconstruct lineage membership, i.e. to cluster sampled sequences according to which came from the same rearrangement events. We call this clustering problem "clonal family inference." In this paper we describe and validate a likelihood-based framework for clonal family inference based on a multi-hidden Markov Model (multi-HMM framework for B cell receptor sequences. We describe an agglomerative algorithm to find a maximum likelihood clustering, two approximate algorithms with various trade-offs of speed versus accuracy, and a third, fast algorithm for finding specific lineages. We show that under simulation these algorithms greatly improve upon existing clonal family inference methods, and that they also give significantly different clusters than previous methods when applied to two real data sets.

  11. Prognostic significance of metallothionein in B-cell lymphomas

    DEFF Research Database (Denmark)

    Poulsen, Christian Bjørn; Borup, Rehannah; Borregaard, Niels

    2006-01-01

    -cell (ABC) and 3 of 9 type-3 lesions. In contrast, MT mRNA was low to undetectable in 16 germinal center B-cell (GCB)-type DLBCLs. Only 1 of 15 patients with up-regulated MT mRNA achieved a sustained remission, suggesting that up-regulated MT mRNA constitutes a significant risk factor for treatment failure...

  12. Engaging the lysosomal compartment to combat B cell malignancies

    DEFF Research Database (Denmark)

    Gronbaek, K.; Jaattela, M.

    2009-01-01

    The combination of rituximab, a type I anti-CD20 mAb, with conventional chemotherapy has significantly improved the outcome of patients with B cell malignancies. Regardless of this success, many patients still relapse with therapy-resistant disease, highlighting the need for the development of m...

  13. Lymphoma classification update: B-cell non-Hodgkin lymphomas.

    Science.gov (United States)

    Jiang, Manli; Bennani, N Nora; Feldman, Andrew L

    2017-05-01

    Lymphomas are classified based on the normal counterpart, or cell of origin, from which they arise. Because lymphocytes have physiologic immune functions that vary both by lineage and by stage of differentiation, the classification of lymphomas arising from these normal lymphoid populations is complex. Recent genomic data have contributed additional complexity. Areas covered: Lymphoma classification follows the World Health Organization (WHO) system, which reflects international consensus and is based on pathological, genetic, and clinical factors. A 2016 revision to the WHO classification of lymphoid neoplasms recently was reported. The present review focuses on B-cell non-Hodgkin lymphomas, the most common group of lymphomas, and summarizes recent changes most relevant to hematologists and other clinicians who care for lymphoma patients. Expert commentary: Lymphoma classification is a continually evolving field that needs to be responsive to new clinical, pathological, and molecular understanding of lymphoid neoplasia. Among the entities covered in this review, the 2016 revision of the WHO classification particularly impact the subclassification and genetic stratification of diffuse large B-cell lymphoma and high-grade B-cell lymphomas, and reflect evolving criteria and nomenclature for indolent B-cell lymphomas and lymphoproliferative disorders.

  14. CD1d(hi)CD5+ B cells expanded by GM-CSF in vivo suppress experimental autoimmune myasthenia gravis.

    Science.gov (United States)

    Sheng, Jian Rong; Quan, Songhua; Soliven, Betty

    2014-09-15

    IL-10-competent subset within CD1d(hi)CD5(+) B cells, also known as B10 cells, has been shown to regulate autoimmune diseases. Whether B10 cells can prevent or suppress the development of experimental autoimmune myasthenia gravis (EAMG) has not been studied. In this study, we investigated whether low-dose GM-CSF, which suppresses EAMG, can expand B10 cells in vivo, and whether adoptive transfer of CD1d(hi)CD5(+) B cells would prevent or suppress EAMG. We found that treatment of EAMG mice with low-dose GM-CSF increased the proportion of CD1d(hi)CD5(+) B cells and B10 cells. In vitro coculture studies revealed that CD1d(hi)CD5(+) B cells altered T cell cytokine profile but did not directly inhibit T cell proliferation. In contrast, CD1d(hi)CD5(+) B cells inhibited B cell proliferation and its autoantibody production in an IL-10-dependent manner. Adoptive transfer of CD1d(hi)CD5(+) B cells to mice could prevent disease, as well as suppress EAMG after disease onset. This was associated with downregulation of mature dendritic cell markers and expansion of regulatory T cells resulting in the suppression of acetylcholine receptor-specific T cell and B cell responses. Thus, our data have provided significant insight into the mechanisms underlying the tolerogenic effects of B10 cells in EAMG. These observations suggest that in vivo or in vitro expansion of CD1d(hi)CD5(+) B cells or B10 cells may represent an effective strategy in the treatment of human myasthenia gravis. Copyright © 2014 by The American Association of Immunologists, Inc.

  15. CD83 Antibody Inhibits Human B Cell Responses to Antigen as well as Dendritic Cell-Mediated CD4 T Cell Responses.

    Science.gov (United States)

    Wong, Kuan Y; Baron, Rebecca; Seldon, Therese A; Jones, Martina L; Rice, Alison M; Munster, David J

    2018-05-15

    Anti-CD83 Ab capable of Ab-dependent cellular cytotoxicity can deplete activated CD83 + human dendritic cells, thereby inhibiting CD4 T cell-mediated acute graft-versus-host disease. As CD83 is also expressed on the surface of activated B lymphocytes, we hypothesized that anti-CD83 would also inhibit B cell responses to stimulation. We found that anti-CD83 inhibited total IgM and IgG production in vitro by allostimulated human PBMC. Also, Ag-specific Ab responses to immunization of SCID mice xenografted with human PBMC were inhibited by anti-CD83 treatment. This inhibition occurred without depletion of all human B cells because anti-CD83 lysed activated CD83 + B cells by Ab-dependent cellular cytotoxicity and spared resting (CD83 - ) B cells. In cultured human PBMC, anti-CD83 inhibited tetanus toxoid-stimulated B cell proliferation and concomitant dendritic cell-mediated CD4 T cell proliferation and expression of IFN-γ and IL-17A, with minimal losses of B cells (80% of B cells but had no effect on CD4 T cell proliferation and cytokine expression. By virtue of the ability of anti-CD83 to selectively deplete activated, but not resting, B cells and dendritic cells, with the latter reducing CD4 T cell responses, anti-CD83 may be clinically useful in autoimmunity and transplantation. Advantages might include inhibited expansion of autoantigen- or alloantigen-specific B cells and CD4 T cells, thus preventing further production of pathogenic Abs and inflammatory cytokines while preserving protective memory and regulatory cells. Copyright © 2018 by The American Association of Immunologists, Inc.

  16. Bruton tyrosine kinase inhibitor ibrutinib (PCI-32765) has significant activity in patients with relapsed/refractory B-cell malignancies.

    Science.gov (United States)

    Advani, Ranjana H; Buggy, Joseph J; Sharman, Jeff P; Smith, Sonali M; Boyd, Thomas E; Grant, Barbara; Kolibaba, Kathryn S; Furman, Richard R; Rodriguez, Sara; Chang, Betty Y; Sukbuntherng, Juthamas; Izumi, Raquel; Hamdy, Ahmed; Hedrick, Eric; Fowler, Nathan H

    2013-01-01

    Survival and progression of mature B-cell malignancies depend on signals from the B-cell antigen receptor, and Bruton tyrosine kinase (BTK) is a critical signaling kinase in this pathway. We evaluated ibrutinib (PCI-32765), a small-molecule irreversible inhibitor of BTK, in patients with B-cell malignancies. Patients with relapsed or refractory B-cell lymphoma and chronic lymphocytic leukemia received escalating oral doses of ibrutinib. Two schedules were evaluated: one, 28 days on, 7 days off; and two, once-daily continuous dosing. Occupancy of BTK by ibrutinib in peripheral blood was monitored using a fluorescent affinity probe. Dose escalation proceeded until either the maximum-tolerated dose (MTD) was achieved or, in the absence of MTD, until three dose levels above full BTK occupancy by ibrutinib. Response was evaluated every two cycles. Fifty-six patients with a variety of B-cell malignancies were treated over seven cohorts. Most adverse events were grade 1 and 2 in severity and self-limited. Dose-limiting events were not observed, even with prolonged dosing. Full occupancy of the BTK active site occurred at 2.5 mg/kg per day, and dose escalation continued to 12.5 mg/kg per day without reaching MTD. Pharmacokinetic data indicated rapid absorption and elimination, yet BTK occupancy was maintained for at least 24 hours, consistent with the irreversible mechanism. Objective response rate in 50 evaluable patients was 60%, including complete response of 16%. Median progression-free survival in all patients was 13.6 months. Ibrutinib, a novel BTK-targeting inhibitor, is well tolerated, with substantial activity across B-cell histologies.

  17. CD70 reverse signaling enhances NK cell function and immunosurveillance in CD27-expressing B-cell malignancies.

    Science.gov (United States)

    Al Sayed, Mohamad F; Ruckstuhl, Carla A; Hilmenyuk, Tamara; Claus, Christina; Bourquin, Jean-Pierre; Bornhauser, Beat C; Radpour, Ramin; Riether, Carsten; Ochsenbein, Adrian F

    2017-07-20

    The interaction of the tumor necrosis factor receptor (TNFR) CD27 with its ligand CD70 is an emerging target to treat cancer. CD27 signaling provides costimulatory signals to cytotoxic T cells but also increases the frequency of regulatory T cells. Similar to other TNFR ligands, CD70 has been shown to initiate intracellular signaling pathways (CD70 reverse signaling). CD27 is expressed on a majority of B-cell non-Hodgkin lymphoma, but its role in the immune control of lymphoma and leukemia is unknown. We therefore generated a cytoplasmic deletion mutant of CD27 (CD27-trunc) to study the role of CD70 reverse signaling in the immunosurveillance of B-cell malignancies in vivo. Expression of CD27-trunc on malignant cells increased the number of tumor-infiltrating interferon γ-producing natural killer (NK) cells. In contrast, the antitumoral T-cell response remained largely unchanged. CD70 reverse signaling in NK cells was mediated via the AKT signaling pathway and increased NK cell survival and effector function. The improved immune control by activated NK cells prolonged survival of CD27-trunc-expressing lymphoma-bearing mice. Finally, CD70 reverse signaling enhanced survival and effector function of human NK cells in a B-cell acute lymphoblastic leukemia xenotransplants model. Therefore, CD70 reverse signaling in NK cells contributes to the immune control of CD27-expressing B-cell lymphoma and leukemia. © 2017 by The American Society of Hematology.

  18. Type I CD20 Antibodies Recruit the B Cell Receptor for Complement-Dependent Lysis of Malignant B Cells

    NARCIS (Netherlands)

    Engelberts, Patrick J.; Voorhorst, Marleen; Schuurman, Janine; van Meerten, Tom; Bakker, Joost M.; Vink, Tom; Mackus, Wendy J. M.; Breij, Esther C. W.; Derer, Stefanie; Valerius, Thomas; van de Winkel, Jan G. J.; Parren, Paul W. H. I.; Beurskens, Frank J.

    2016-01-01

    Human IgG1 type I CD20 Abs, such as rituximab and ofatumumab (OFA), efficiently induce complement-dependent cytotoxicity (CDC) of CD20(+) B cells by binding of C1 to hexamerized Fc domains. Unexpectedly, we found that type I CD20 Ab F(ab ')2 fragments, as well as C1q-binding-deficient IgG mutants,

  19. Epigenetic inactivation of Notch-Hes pathway in human B-cell acute lymphoblastic leukemia.

    Directory of Open Access Journals (Sweden)

    Shao-Qing Kuang

    Full Text Available The Notch pathway can have both oncogenic and tumor suppressor roles, depending on cell context. For example, Notch signaling promotes T cell differentiation and is leukemogenic in T cells, whereas it inhibits early B cell differentiation and acts as a tumor suppressor in B cell leukemia where it induces growth arrest and apoptosis. The regulatory mechanisms that contribute to these opposing roles are not understood. Aberrant promoter DNA methylation and histone modifications are associated with silencing of tumor suppressor genes and have been implicated in leukemogenesis. Using methylated CpG island amplification (MCA/DNA promoter microarray, we identified Notch3 and Hes5 as hypermethylated in human B cell acute lymphoblastic leukemia (ALL. We investigated the methylation status of other Notch pathway genes by bisulfite pyrosequencing. Notch3, JAG1, Hes2, Hes4 and Hes5 were frequently hypermethylated in B leukemia cell lines and primary B-ALL, in contrast to T-ALL cell lines and patient samples. Aberrant methylation of Notch3 and Hes5 in B-ALL was associated with gene silencing and was accompanied by decrease of H3K4 trimethylation and H3K9 acetylation and gain of H3K9 trimethylation and H3K27 trimethylation. 5-aza-2'-deoxycytidine treatment restored Hes5 expression and decreased promoter hypermethylation in most leukemia cell lines and primary B-ALL samples. Restoration of Hes5 expression by lentiviral transduction resulted in growth arrest and apoptosis in Hes5 negative B-ALL cells but not in Hes5 expressing T-ALL cells. These data suggest that epigenetic modifications are implicated in silencing of tumor suppressor of Notch/Hes pathway in B-ALL.

  20. Epigenetic inactivation of Notch-Hes pathway in human B-cell acute lymphoblastic leukemia.

    Science.gov (United States)

    Kuang, Shao-Qing; Fang, Zhihong; Zweidler-McKay, Patrick A; Yang, Hui; Wei, Yue; Gonzalez-Cervantes, Emilio A; Boumber, Yanis; Garcia-Manero, Guillermo

    2013-01-01

    The Notch pathway can have both oncogenic and tumor suppressor roles, depending on cell context. For example, Notch signaling promotes T cell differentiation and is leukemogenic in T cells, whereas it inhibits early B cell differentiation and acts as a tumor suppressor in B cell leukemia where it induces growth arrest and apoptosis. The regulatory mechanisms that contribute to these opposing roles are not understood. Aberrant promoter DNA methylation and histone modifications are associated with silencing of tumor suppressor genes and have been implicated in leukemogenesis. Using methylated CpG island amplification (MCA)/DNA promoter microarray, we identified Notch3 and Hes5 as hypermethylated in human B cell acute lymphoblastic leukemia (ALL). We investigated the methylation status of other Notch pathway genes by bisulfite pyrosequencing. Notch3, JAG1, Hes2, Hes4 and Hes5 were frequently hypermethylated in B leukemia cell lines and primary B-ALL, in contrast to T-ALL cell lines and patient samples. Aberrant methylation of Notch3 and Hes5 in B-ALL was associated with gene silencing and was accompanied by decrease of H3K4 trimethylation and H3K9 acetylation and gain of H3K9 trimethylation and H3K27 trimethylation. 5-aza-2'-deoxycytidine treatment restored Hes5 expression and decreased promoter hypermethylation in most leukemia cell lines and primary B-ALL samples. Restoration of Hes5 expression by lentiviral transduction resulted in growth arrest and apoptosis in Hes5 negative B-ALL cells but not in Hes5 expressing T-ALL cells. These data suggest that epigenetic modifications are implicated in silencing of tumor suppressor of Notch/Hes pathway in B-ALL.

  1. Generation of Recombinant Monoclonal Antibodies from Immunised Mice and Rabbits via Flow Cytometry and Sorting of Antigen-Specific IgG+ Memory B Cells.

    Directory of Open Access Journals (Sweden)

    Dale O Starkie

    Full Text Available Single B cell screening strategies, which avoid both hybridoma fusion and combinatorial display, have emerged as important technologies for efficiently sampling the natural antibody repertoire of immunized animals and humans. Having access to a range of methods to interrogate different B cell subsets provides an attractive option to ensure large and diverse panels of high quality antibody are produced. The generation of multiple antibodies and having the ability to find rare B cell clones producing IgG with unique and desirable characteristics facilitates the identification of fit-for-purpose molecules that can be developed into therapeutic agents or research reagents. Here, we describe a multi-parameter flow cytometry single-cell sorting technique for the generation of antigen-specific recombinant monoclonal antibodies from single IgG+ memory B cells. Both mouse splenocytes and rabbit PBMC from immunised animals were used as a source of B cells. Reagents staining both B cells and other unwanted cell types enabled efficient identification of class-switched IgG+ memory B cells. Concurrent staining with antigen labelled separately with two spectrally-distinct fluorophores enabled antigen-specific B cells to be identified, i.e. those which bind to both antigen conjugates (double-positive. These cells were then typically sorted at one cell per well using FACS directly into a 96-well plate containing reverse transcriptase reaction mix. Following production of cDNA, PCR was performed to amplify cognate heavy and light chain variable region genes and generate transcriptionally-active PCR (TAP fragments. These linear expression cassettes were then used directly in a mammalian cell transfection to generate recombinant antibody for further testing. We were able to successfully generate antigen-specific recombinant antibodies from both the rabbit and mouse IgG+ memory B cell subset within one week. This included the generation of an anti-TNFR2 blocking

  2. Assessment of CD37 B-cell antigen and cell of origin significantly improves risk prediction in diffuse large B-cell lymphoma

    DEFF Research Database (Denmark)

    Xu-Monette, Zijun Y; Li, Ling; Byrd, John C

    2016-01-01

    CD37 (tetraspanin TSPAN26) is a B-cell surface antigen widely expressed on mature B cells. CD37 is involved in immune regulation and tumor suppression but its function has not been fully elucidated. We assessed CD37 expression in de novo diffuse large B-cell lymphoma (DLBCL), and investigated its...

  3. Effects of anti-CD40 mAb on inducing malignant B cells proliferation arrest and apoptosis and its mechanism

    International Nuclear Information System (INIS)

    Tang Lin; Zhuang Yumei; Zhou Zhaohua; Yu Gehua; Pan Jianzhong; Zhang Xueguang

    2002-01-01

    Objective: To study the expression of CD 40 molecule and the biological effects mediated by CD 40 molecules on malignant B cells. Methods: Agonistic anti-human CD 40 monoclonal antibody (clone 5C11) was added to cell culture system. Cell counting, PI staining, Annexin-V staining and flow cytometric analysis were used to study the behavior of malignant B cell lines after treatment with mAb clone 5C11. Results: 5C11 induced homotypic aggregation and proliferation arrest and mediated apoptosis in multiple myeloma cell line XG2 that expressed CD 40 strongly; 5C11 induced B lymphoma cell line Daudi homotypic aggregation and proliferation arrest and apoptosis, the apoptosis of XG2 and Daudi by CD40 activation was not mediated by TNF. Conclusion: Agonistic anti-CD 40 mAb 5C11 can inhibit the proliferation of malignant B cells by inducing them to die apoplectically

  4. Siglec-7 tetramers characterize B-cell subpopulations and leukemic blasts.

    Science.gov (United States)

    Gieseke, Friederike; Mang, Philippa; Viebahn, Susanne; Sonntag, Inga; Kruchen, Anne; Erbacher, Annika; Pfeiffer, Matthias; Handgretinger, Rupert; Müller, Ingo

    2012-08-01

    Cell surface glycosylation has important regulatory functions in the maturation, activation, and homeostasis of lymphocytes. The family of human sialic acid-binding immunoglobulin-like lectins (siglecs) comprises inhibitory as well as activating receptors intimately involved in the regulation of immune responses. Analyses of the interaction between siglecs and glycans are hampered by the low affinity of this interaction. Therefore, we expressed siglec-7 in eukaryotic cells, allowing for glycosylation, and oligomerized the protein in analogy to MHC tetramers. Using this tool, flow cytometric analysis of lymphocytes became possible. Sialic acid-dependent binding of siglec-7 tetramers was confirmed by glycan array analysis and loss of siglec tetramer binding after neuraminidase treatment of lymphocytes. In contrast to most lymphocyte subpopulations, which showed high siglec-7 ligand expression, B-cell subpopulations could be further subdivided according to different siglec-7 ligand expression levels. We also analyzed blasts from acute lymphoblastic leukemias of the B-cell lineage as well as the T-cell lineage, since malignant transformation is often associated with aberrant cell surface glycosylation. While pediatric T-ALL blasts highly expressed siglec-7 ligands, siglec-7 ligands were barely detectable on cALL blasts. Taken together, oligomerization of recombinant soluble siglec-7 enabled flow cytometric identification of physiologic lymphocyte subpopulations and malignant blasts. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Oncogenic Notch signaling in T-cell and B-cell lymphoproliferative disorders.

    Science.gov (United States)

    Chiang, Mark Y; Radojcic, Vedran; Maillard, Ivan

    2016-07-01

    This article highlights recent discoveries about Notch activation and its oncogenic functions in lymphoid malignancies, and discusses the therapeutic potential of Notch inhibition. NOTCH mutations arise in a broad spectrum of lymphoid malignancies and are increasingly scrutinized as putative therapeutic targets. In T-cell acute lymphoblastic leukemia (T-ALL), NOTCH1 mutations affect the extracellular negative regulatory region and lead to constitutive Notch activation, although mutated receptors remain sensitive to Notch ligands. Other NOTCH1 mutations in T-ALL and NOTCH1/2 mutations in multiple B-cell malignancies truncate the C-terminal proline (P), glutamic acid (E), serine (S), threonine (T)-rich (PEST) domain, leading to decreased Notch degradation after ligand-mediated activation. Thus, targeting Notch ligand-receptor interactions could provide therapeutic benefits. In addition, we discuss recent reports on clinical testing of Notch inhibitors in T-ALL that influenced contemporary thinking on the challenges of targeting Notch in cancer. We review advances in the laboratory to address these challenges in regards to drug targets, the Notch-driven metabolome, and the sophisticated protein-protein interactions at Notch-dependent superenhancers that underlie oncogenic Notch functions. Notch signaling is a recurrent oncogenic pathway in multiple T- and B-cell lymphoproliferative disorders. Understanding the complexity and consequences of Notch activation is critical to define optimal therapeutic strategies targeting the Notch pathway.

  6. Targeting Endothelial Adhesion Molecule Transcription for Treatment of Inflammatory Disease: A Proof-of-Concept Study

    Directory of Open Access Journals (Sweden)

    Liam M. Ashander

    2016-01-01

    Full Text Available Targeting the endothelial adhesion molecules that control leukocyte trafficking into a tissue has been explored as a biological therapy for inflammatory diseases. However, these molecules also participate in leukocyte migration for immune surveillance, and inhibiting the physiological level of an adhesion molecule might promote infection or malignancy. We explored the concept of targeting endothelial adhesion molecule transcription during inflammation in a human system. Intercellular adhesion molecule 1 (ICAM-1 mediates leukocyte migration across the retinal endothelium in noninfectious posterior uveitis. We observed an increase in the transcription factor, nuclear factor of kappa light polypeptide gene enhancer in B-cells 1 (NF-κB1, in parallel with ICAM-1, in human retinal endothelial cells treated with tumor necrosis factor-alpha (TNF-α, and identified putative binding sites for NF-κB1 within the ICAM-1 regulatory region. We targeted induced NF-κB1 expression in endothelial cells with small interfering (siRNA. Knockdown of NF-κB1 significantly decreased cell surface expression of ICAM-1 protein induced by TNF-α but did not reduce constitutive ICAM-1 expression. Consistently, NF-κB1 knockdown significantly reduced leukocyte binding to cell monolayers in the presence of TNF-α but did not impact baseline binding. Findings of this proof-of-concept study indicate that induced transcription of endothelial adhesion molecules might be targeted therapeutically for inflammatory disease in humans.

  7. Homeostatic 'bystander' proliferation of human peripheral blood B cells in response to polyclonal T-cell stimulation in vitro.

    Science.gov (United States)

    Jasiulewicz, Aleksandra; Lisowska, Katarzyna A; Pietruczuk, Krzysztof; Frąckowiak, Joanna; Fulop, Tamas; Witkowski, Jacek M

    2015-11-01

    The mechanisms of maintenance of adequate numbers of B lymphocytes and of protective levels of immunoglobulins in the absence of antigenic (re)stimulation remain not fully understood. Meanwhile, our results presented here show that both peripheral blood naive and memory B cells can be activated strongly and non-specifically (in a mitogen-like fashion) in 5-day in vitro cultures of anti-CD3- or concanavalin A (Con A)-stimulated peripheral blood mononuclear cells of healthy people. This polyclonal, bystander activation of the B cells includes multiple divisions of most of them (assessed here by the flow cytometric technique of dividing cell tracking) and significant antibody [immunoglobulin M (IgM) and IgG] secretion. Observed proliferation of the CD19(+) B cells depends on contact with stimulated T helper (Th) cells (via CD40-CD40L interaction) and on the response of B cells to secreted interleukins IL-5, IL-10 and IL-4, and is correlated with the levels of these Th-derived molecules, while it does not involve the ligation of the BCR/CD19 complex. We suggest that the effect might reflect the situation occurring in vivo as the homeostatic proliferation of otherwise non-stimulated, peripheral B lymphocytes, providing an always ready pool for efficient antibody production to any new (or cognate) antigen challenge. © The Japanese Society for Immunology. 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Nanoscale mapping and organization analysis of target proteins on cancer cells from B-cell lymphoma patients

    Energy Technology Data Exchange (ETDEWEB)

    Li, Mi [State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xiao, Xiubin [Department of Lymphoma, Affiliated Hospital of Military Medical Academy of Sciences, Beijing 100071 (China); Liu, Lianqing, E-mail: lqliu@sia.cn [State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016 (China); Xi, Ning, E-mail: xin@egr.msu.edu [State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016 (China); Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong (China); Wang, Yuechao; Dong, Zaili [State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016 (China); Zhang, Weijing, E-mail: zhangwj3072@163.com [Department of Lymphoma, Affiliated Hospital of Military Medical Academy of Sciences, Beijing 100071 (China)

    2013-11-01

    CD20, a membrane protein highly expressed on most B-cell lymphomas, is an effective target demonstrated in clinical practice for treating B-cell non-Hodgkin's lymphoma (NHL). Rituximab is a monoclonal antibody against CD20. In this work, we applied atomic force microscopy (AFM) to map the nanoscale distribution of CD20 molecules on the surface of cancer cells from clinical B-cell NHL patients under the assistance of ROR1 fluorescence recognition (ROR1 is a specific cell surface marker exclusively expressed on cancer cells). First, the ROR1 fluorescence labeling experiments showed that ROR1 was expressed on cancer cells from B-cell lymphoma patients, but not on normal cells from healthy volunteers. Next, under the guidance of ROR1 fluorescence, the rituximab-conjugated AFM tips were moved to cancer cells to image the cellular morphologies and detect the CD20-rituximab interactions on the cell surfaces. The distribution maps of CD20 on cancer cells were constructed by obtaining arrays of (16×16) force curves in local areas (500×500 nm{sup 2}) on the cell surfaces. The experimental results provide a new approach to directly investigate the nanoscale distribution of target protein on single clinical cancer cells. - Highlights: • Cancer cells were recognized from healthy cells by ROR1 fluorescence labeling. • The nanoscale distribution of CD20 on cancer cells was characterized. • The distribution of CD20 was non-uniform on the surface of cancer cells.

  9. Modulation of redox regulatory molecules and electron transport chain activity in muscle of air breathing fish Heteropneustes fossilis under air exposure stress.

    Science.gov (United States)

    Paital, Biswaranjan

    2014-01-01

    Responses of redox regulatory system to long-term survival (>18 h) of the catfish Heteropneustes fossilis in air are not yet understood. Lipid and protein oxidation level, oxidant (H2O2) generation, antioxidative status (levels of superoxide dismutase, catalase, glutathione peroxidase and reductase, ascorbic acid and non-protein sulfhydryl) and activities of respiratory complexes (I, II, III and IV) in mitochondria were investigated in muscle of H. fossilis under air exposure condition (0, 3, 6, 12 and 18 h at 25 °C). The increased levels of both H2O2 and tissue oxidation were observed due to the decreased activities of antioxidant enzymes in muscle under water deprivation condition. However, ascorbic acid and non-protein thiol groups were the highest at 18 h air exposure time. A linear increase in complex II activity with air exposure time and an increase up to 12 h followed by a decrease in activity of complex I at 18 h were observed. Negative correlation was observed for complex III and V activity with exposure time. Critical time to modulate the above parameters was found to be 3 h air exposure. Dehydration induced oxidative stress due to modulation of electron transport chain and redox metabolizing enzymes in muscle of H. fossilis was clearly observed. Possible contribution of redox regulatory system in muscle tissue of the fish for long-term survival in air is elucidated. Results of the present study may be useful to understand the redox metabolism in muscle of fishes those are exposed to air in general and air breathing fishes in particular.

  10. 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.

  11. 324 Facility B-cell quality process plan

    International Nuclear Information System (INIS)

    Carlson, J.L.

    1998-01-01

    B-Cell is currently being cleaned out (i.e., removal of equipment, fixtures and residual radioactive materials) and deactivated. TPA Milestone M-89-02 dictates that all mixed waste and equipment be removed from B-Cell by 5/31/99. The following sections describe the major activities that remain for completion of the TPA milestone. These include: Size Reduce Tank 119 and Miscellaneous Equipment; Load and Ship Low-Level Waste; Remove and Size Reduce the 1B Rack; Collect Dispersible Material from Cell Floor; Remove and Size Reduce the 2A Rack; Size Reduce the 1A Rack; Load and Ship Mixed Waste to PUREX Tunnels; and Move Spent Fuel to A-Cell;

  12. Rituximab and chemotherapy in diffuse large B-cell lymphoma.

    Science.gov (United States)

    Sonet, Anne; Bosly, André

    2009-06-01

    Rituximab is an anti-CD20 chimeric monoclonal antibody with activity in nearly all subtypes of B-cell lymphomas. Association of rituximab with chemotherapy (mostly the cyclophosphamide, doxorubicin, vincristine and prednisolone [CHOP] regimen) in diffuse large B-cell lymphoma (DLBCL) represents an extraordinary revolution in the prognosis of DLBCL, and is the new standard of therapy in elderly and young, low-risk patients. Despite the lack of randomized, clinical trials in younger patients with high risk, rituximab is also a standard of care in these patients in clinical practice, at least in North America. The practice is based on observational trials (e.g., the British Columbia Registry) and the missing logic in classifying patients as 'younger' or 'older': 60 years old or 65 years old. In Europe, trials are ongoing to establish the best treatment for young, high-risk patients. Association of rituximab and chemotherapy deeply modifies prognostic factors defined before the rituximab era.

  13. Th1 and Th2 help for B cells

    DEFF Research Database (Denmark)

    Poudrier, J; Owens, T

    1995-01-01

    that IL-5 (125 U/ml) synergizes with Th1 cells to induce B cell responses to IL-2, that are maintained following T-cell removal, e.g. autonomous. Th1 help in the absence of IL-5 resulted in weak or undetectable responses following T cell removal. The mechanism of IL-5 synergy involved persistence of IL-2R...... anti-Ig did not circumvent the need for IL-5 for autonomous IL-2 responses. Consistent with the above, interaction with an IL-5-producing Th2 clone induced strong autonomous B cell responses to IL-2. Qualitative differences of Th2 help over that of Th1 may thus be attributable to their differential...

  14. T. B-cell subpopulation in patients with malignant diseases

    International Nuclear Information System (INIS)

    Ogawa, Motoyoshi; Goto, Tatsuhiko; Naruto, Mamiko.

    1978-01-01

    T, B cells in the peripheural blood of patients with malignant diseases were investigated. The percentages of T cells in patients with malignant lymphomas correlated to the extent of disease determined by clinical stagings of Ann Arbor's classification, in stages III and IV T-cells decreased to compare with those in stages I and II, while B-cells did not show any changes. Absolute numbers of lymphocytes, blastogenesis induced by PHA or PWM decreased remarkably during combination chemotherapies and during radiotherapy whereas the percentages of T-cells measuring in the same patients did not influenced consistently by these treatments. The DNA pattern of lymphocytes during treatments was examined by Flow-Microphotometry and the result suggested that those lymphocytes were damaged by treatments and subsequently they were refractory to the action of mitogens. The results indicate that selective timing needs between chemotherapy and immunotherapy. (auth.)

  15. Epigenetic Impact on EBV Associated B-Cell Lymphomagenesis

    Directory of Open Access Journals (Sweden)

    Shatadru Ghosh Roy

    2016-11-01

    Full Text Available Epigenetic modifications leading to either transcriptional repression or activation, play an indispensable role in the development of human cancers. Epidemiological study revealed that approximately 20% of all human cancers are associated with tumor viruses. Epstein-Barr virus (EBV, the first human tumor virus, demonstrates frequent epigenetic alterations on both viral and host genomes in associated cancers—both of epithelial and lymphoid origin. The cell type-dependent different EBV latent gene expression patterns appear to be determined by the cellular epigenetic machinery and similarly viral oncoproteins recruit epigenetic regulators in order to deregulate the cellular gene expression profile resulting in several human cancers. This review elucidates the epigenetic consequences of EBV–host interactions during development of multiple EBV-induced B-cell lymphomas, which may lead to the discovery of novel therapeutic interventions against EBV-associated B-cell lymphomas by alteration of reversible patho-epigenetic markings.

  16. Bilateral proliferative retinopathy in B-cell acute lymphoblastic leukemia

    Directory of Open Access Journals (Sweden)

    Devesh Kumawat

    2018-01-01

    Full Text Available A 4-year-old child with B-cell acute lymphoblastic leukemia presented with vitreous hemorrhage due to proliferative retinopathy in both eyes. Pars plana vitrectomy was performed in both eyes to clear nonresolving vitreous hemorrhage after systemic stabilization. Visual recovery was limited by the disc drag in the right eye and subfoveal exudation in the left eye. Etiopathogenesis and management of proliferative retinopathy in acute leukemias are discussed.

  17. Genetics and Pathogenesis of Diffuse Large B-Cell Lymphoma.

    Science.gov (United States)

    Schmitz, Roland; Wright, George W; Huang, Da Wei; Johnson, Calvin A; Phelan, James D; Wang, James Q; Roulland, Sandrine; Kasbekar, Monica; Young, Ryan M; Shaffer, Arthur L; Hodson, Daniel J; Xiao, Wenming; Yu, Xin; Yang, Yandan; Zhao, Hong; Xu, Weihong; Liu, Xuelu; Zhou, Bin; Du, Wei; Chan, Wing C; Jaffe, Elaine S; Gascoyne, Randy D; Connors, Joseph M; Campo, Elias; Lopez-Guillermo, Armando; Rosenwald, Andreas; Ott, German; Delabie, Jan; Rimsza, Lisa M; Tay Kuang Wei, Kevin; Zelenetz, Andrew D; Leonard, John P; Bartlett, Nancy L; Tran, Bao; Shetty, Jyoti; Zhao, Yongmei; Soppet, Dan R; Pittaluga, Stefania; Wilson, Wyndham H; Staudt, Louis M

    2018-04-12

    Diffuse large B-cell lymphomas (DLBCLs) are phenotypically and genetically heterogeneous. Gene-expression profiling has identified subgroups of DLBCL (activated B-cell-like [ABC], germinal-center B-cell-like [GCB], and unclassified) according to cell of origin that are associated with a differential response to chemotherapy and targeted agents. We sought to extend these findings by identifying genetic subtypes of DLBCL based on shared genomic abnormalities and to uncover therapeutic vulnerabilities based on tumor genetics. We studied 574 DLBCL biopsy samples using exome and transcriptome sequencing, array-based DNA copy-number analysis, and targeted amplicon resequencing of 372 genes to identify genes with recurrent aberrations. We developed and implemented an algorithm to discover genetic subtypes based on the co-occurrence of genetic alterations. We identified four prominent genetic subtypes in DLBCL, termed MCD (based on the co-occurrence of MYD88 L265P and CD79B mutations), BN2 (based on BCL6 fusions and NOTCH2 mutations), N1 (based on NOTCH1 mutations), and EZB (based on EZH2 mutations and BCL2 translocations). Genetic aberrations in multiple genes distinguished each genetic subtype from other DLBCLs. These subtypes differed phenotypically, as judged by differences in gene-expression signatures and responses to immunochemotherapy, with favorable survival in the BN2 and EZB subtypes and inferior outcomes in the MCD and N1 subtypes. Analysis of genetic pathways suggested that MCD and BN2 DLBCLs rely on "chronic active" B-cell receptor signaling that is amenable to therapeutic inhibition. We uncovered genetic subtypes of DLBCL with distinct genotypic, epigenetic, and clinical characteristics, providing a potential nosology for precision-medicine strategies in DLBCL. (Funded by the Intramural Research Program of the National Institutes of Health and others.).

  18. Complement-dependent transport of antigen into B cell follicles

    DEFF Research Database (Denmark)

    Gonzalez, Santiago F.; Lukacs-Kornek, Veronika; Kuligowski, Michael P.

    2010-01-01

    an additional novel pathway in which complement C3 and its receptors enhance humoral immunity through delivery of Ag to the B cell compartment. In this review, we discuss this pathway and highlight several novel exceptions recently found with a model influenza vaccine, such as mannose-binding lectin...... opsonization of influenza and uptake by macrophages, and the capture of virus by dendritic cells residing in the medullary compartment of peripheral lymph nodes....

  19. The small FOXP1 isoform predominantly expressed in activated B cell-like diffuse large B-cell lymphoma and full-length FOXP1 exert similar oncogenic and transcriptional activity in human B cells.

    Science.gov (United States)

    van Keimpema, Martine; Grüneberg, Leonie J; Schilder-Tol, Esther J M; Oud, Monique E C M; Beuling, Esther A; Hensbergen, Paul J; de Jong, Johann; Pals, Steven T; Spaargaren, Marcel

    2017-03-01

    The forkhead transcription factor FOXP1 is generally regarded as an oncogene in activated B cell-like diffuse large B-cell lymphoma. Previous studies have suggested that a small isoform of FOXP1 rather than full-length FOXP1, may possess this oncogenic activity. Corroborating those studies, we herein show that activated B cell-like diffuse large B-cell lymphoma cell lines and primary activated B cell-like diffuse large B-cell lymphoma cells predominantly express a small FOXP1 isoform, and that the 5'-end of the Foxp1 gene is a common insertion site in murine lymphomas in leukemia virus- and transposon-mediated insertional mutagenesis screens. By combined mass spectrometry, (quantative) reverse transcription polymerase chain reaction/sequencing, and small interfering ribonucleic acid-mediated gene silencing, we determined that the small FOXP1 isoform predominantly expressed in activated B cell-like diffuse large B-cell lymphoma lacks the N-terminal 100 amino acids of full-length FOXP1. Aberrant overexpression of this FOXP1 isoform (ΔN100) in primary human B cells revealed its oncogenic capacity; it repressed apoptosis and plasma cell differentiation. However, no difference in potency was found between this small FOXP1 isoform and full-length FOXP1. Furthermore, overexpression of full-length FOXP1 or this small FOXP1 isoform in primary B cells and diffuse large B-cell lymphoma cell lines resulted in similar gene regulation. Taken together, our data indicate that this small FOXP1 isoform and full-length FOXP1 have comparable oncogenic and transcriptional activity in human B cells, suggesting that aberrant expression or overexpression of FOXP1, irrespective of the specific isoform, contributes to lymphomagenesis. These novel insights further enhance the value of FOXP1 for the diagnostics, prognostics, and treatment of diffuse large B-cell lymphoma patients. Copyright© Ferrata Storti Foundation.

  20. Quantitative regulation of B cell division destiny by signal strength.

    Science.gov (United States)

    Turner, Marian L; Hawkins, Edwin D; Hodgkin, Philip D

    2008-07-01

    Differentiation to Ab secreting and isotype-switched effector cells is tightly linked to cell division and therefore the degree of proliferation strongly influences the nature of the immune response. The maximum number of divisions reached, termed the population division destiny, is stochastically distributed in the population and is an important parameter in the quantitative outcome of lymphocyte responses. In this study, we further assessed the variables that regulate B cell division destiny in vitro in response to T cell- and TLR-dependent stimuli. Both the concentration and duration of stimulation were able to regulate the average maximum number of divisions undergone for each stimulus. Notably, a maximum division destiny was reached during provision of repeated saturating stimulation, revealing that an intrinsic limit to proliferation exists even under these conditions. This limit was linked directly to division number rather than time of exposure to stimulation and operated independently of the survival regulation of the cells. These results demonstrate that a B cell population's division destiny is regulable by the stimulatory conditions up to an inherent maximum value. Division destiny is a crucial parameter in regulating the extent of B cell responses and thereby also the nature of the immune response mounted.

  1. Generation of memory B cells and their reactivation.

    Science.gov (United States)

    Inoue, Takeshi; Moran, Imogen; Shinnakasu, Ryo; Phan, Tri Giang; Kurosaki, Tomohiro

    2018-05-01

    The successful establishment of humoral memory response depends on at least two layers of defense. Pre-existing protective antibodies secreted by long-lived plasma cells act as a first line of defense against reinfection ("constitutive humoral memory"). Previously, a second line of defense in which pathogen-experienced memory B cells are rapidly reactivated to produce antibodies ("reactive humoral memory"), was considered as simply a back-up system for the first line (particularly for re-infection with homologous viruses). However, in the case of re-infection with similar but different strains of viruses, or in response to viral escape mutants, the reactive humoral memory plays a crucial role. Here, we review recent progress in our understanding of how memory B cells are generated in the pre-GC stage and during the GC reaction, and how these memory B cells are robustly reactivated with the help of memory Tfh cells to generate the secondary antibody response. In addition, we discuss how these advances may be relevant to the quest for a vaccine that can induce broadly reactive antibodies against influenza and HIV. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. B-cell-depleting Therapy in Systemic Lupus Erythematosus

    Science.gov (United States)

    Ramos-Casals, Manuel; Sanz, Iñaki; Bosch, Xavier; Stone, John H.; Khamashta, Munther A.

    2014-01-01

    The emergence of a new class of agents (B-cell-depleting therapies) has opened a new era in the therapeutic approach to systemic lupus erythematosus, with belimumab being the first drug licensed for use in systemic lupus erythematosus in more than 50 years. Four agents deserve specific mention: rituximab, ocrelizumab, epratuzumab, and belimumab. Controlled trials have shown negative results for rituximab, promising results for epratuzumab, and positive results for belimumab. Despite these negative results, rituximab is the most-used agent in patients who do not respond or are intolerant to standard therapy and those with life-threatening presentations. B-cell-depleting agents should not be used in patients with mild disease and should be tailored according to individual patient characteristics, including ethnicity, organ involvement, and the immunological profile. Forthcoming studies of B-cell-directed strategies, particularly data from investigations of off-label rituximab use and postmarketing studies of belimumab, will provide new insights into the utility of these treatments in the routine management of patients with systemic lupus erythematosus. PMID:22444096

  3. CD3-positive B cells: a storage-dependent phenomenon.

    Directory of Open Access Journals (Sweden)

    Angela Nagel

    Full Text Available The majority of clinical studies requires extensive management of human specimen including e.g. overnight shipping of blood samples in order to convey the samples in a central laboratory or to simultaneously analyze large numbers of patients. Storage of blood samples for periods of time before in vitro/ex vivo testing is known to influence the antigen expression on the surface of lymphocytes. In this context, the present results show for the first time that the T cell antigen CD3 can be substantially detected on the surface of human B cells after ex vivo storage and that the degree of this phenomenon critically depends on temperature and duration after blood withdrawal. The appearance of CD3 on the B cell surface seems to be a result of contact-dependent antigen exchange between T and B lymphocytes and is not attributed to endogenous production by B cells. Since cellular subsets are often classified by phenotypic analyses, our results indicate that ex vivo cellular classification in peripheral blood might result in misleading interpretations. Therefore, in order to obtain results reflecting the in vivo situation, it is suggested to minimize times of ex vivo blood storage after isolation of PBMC. Moreover, to enable reproducibility of results between different research groups and multicenter studies, we would emphasize the necessity to specify and standardize the storage conditions, which might be the basis of particular findings.

  4. SHIP-1 Deficiency in AID+ B Cells Leads to the Impaired Function of B10 Cells with Spontaneous Autoimmunity.

    Science.gov (United States)

    Chen, Yingjia; Hu, Fanlei; Dong, Xuejiao; Zhao, Meng; Wang, Jing; Sun, Xiaolin; Kim, Tae Jin; Li, Zhanguo; Liu, Wanli

    2017-11-01

    Unlike conventional B cells, regulatory B cells exhibit immunosuppressive functions to downregulate inflammation via IL-10 production. However, the molecular mechanism regulating the production of IL-10 is not fully understood. In this study, we report the finding that activation-induced cytidine deaminase (AID) is highly upregulated in the IL-10-competent B cell (B10) cell from Innp5d fl/fl Aicda Cre/+ mice, whereas the 5' inositol phosphatase SHIP-1 is downregulated. Notably, SHIP-1 deficiency in AID + B cells leads to a reduction in cell count and impaired IL-10 production by B10 cells. Furthermore, the Innp5d fl/fl Aicda Cre/+ mouse model shows B cell-dependent autoimmune lupus-like phenotypes, such as elevated IgG serum Abs, formation of spontaneous germinal centers, production of anti-dsDNA and anti-nuclear Abs, and the obvious deposition of IgG immune complexes in the kidney with age. We observe that these lupus-like phenotypes can be reversed by the adoptive transfer of B10 cells from control Innp5d fl/fl mice, but not from the Innp5d fl/fl Aicda Cre/+ mice. This finding highlights the importance of defective B10 cells in Innp5d fl/fl Aicda Cre/+ mice. Whereas p-Akt is significantly upregulated, MAPK and AP-1 activation is impaired in B10 cells from Innp5d fl/fl Aicda Cre/+ mice, resulting in the reduced production of IL-10. These results show that SHIP-1 is required for the maintenance of B10 cells and production of IL-10, and collectively suggests that SHIP-1 could be a new potential therapeutic target for the treatment of autoimmune diseases. Copyright © 2017 by The American Association of Immunologists, Inc.

  5. Pathological Role of Tonsillar B Cells in IgA Nephropathy

    Directory of Open Access Journals (Sweden)

    Yusuke Suzuki

    2011-01-01

    Full Text Available Although impaired immune regulation along the mucosa-bone marrow axis has been postulated to play an important role, the pathogenesis of IgA nephropathy (IgAN is unknown; thus, no disease-specific therapy for this disease exists. The therapeutic efficacy of tonsillectomy or tonsillectomy in combination with steroid pulse therapy for IgAN has been discussed. Although randomized control trials for these therapies are ongoing in Japan, the scientific rationale for these therapies remains obscure. It is now widely accepted that abnormally glycosylated IgA1 and its related immune complex (IC are probably key molecules for the pathogenesis, and are thus considered possible noninvasive biomarkers for this disease. Emerging evidence indicates that B cells in mucosal infections, particularly in tonsillitis, may produce the nephritogenic IgA. In this paper, we briefly summarize characteristics of the nephritogenic IgA/IgA IC, responsible B cells, and underlying mechanisms. This clinical and experimental information may provide important clues for a therapeutic rationale.

  6. TRPM4 expression is associated with activated B cell subtype and poor survival in diffuse large B cell lymphoma

    DEFF Research Database (Denmark)

    Loo, Suet K; Ch'ng, Ewe S; Md Salleh, Md Salzihan

    2017-01-01

    to investigate TRPM4 protein expression pattern in non-malignant tissues and DLBCL cases, and its association with clinico-demographic parameters and survival in DLBCL. METHODS AND RESULTS: Analysis of publicly available DLBCL microarray data sets showed that TRPM4 transcripts were up-regulated in DLBCL compared...... to normal germinal centre B (GCB) cells, were expressed more highly in the activated B cell-like DLBCL (ABC-DLBCL) subtype and higher TRPM4 transcripts conferred worse overall survival (OS) in R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone)-treated DLBCL cases (P ... immunohistochemical analysis showed that TRPM4 was expressed in various human tissues but not in normal B cells within lymphoid tissues (reactive tonsil, lymph node and appendix). TRPM4 protein was present in 26% (n = 49 of 189) of our cohort of R-CHOP-treated DLBCL cases and this was associated significantly...

  7. The Scaffolding Protein Synapse-Associated Protein 97 is Required for Enhanced Signaling Through Isotype-Switched IgG Memory B Cell Receptors

    Science.gov (United States)

    Liu, Wanli; Chen, Elizabeth; Zhao, Xing Wang; Wan, Zheng Peng; Gao, Yi Ren; Davey, Angel; Huang, Eric; Zhang, Lijia; Crocetti, Jillian; Sandoval, Gabriel; Joyce, M. Gordon; Miceli, Carrie; Lukszo, Jan; Aravind, L.; Swat, Wojciech; Brzostowski, Joseph; Pierce, Susan K.

    2012-01-01

    Memory B cells are generated during an individual's first encounter with a foreign antigen and respond to re-encounter with the same antigen through cell surface immunoglobulin G (IgG) B cell receptors (BCRs) resulting in rapid, high-titered IgG antibody responses. Despite a central role for IgG BCRs in B cell memory, our understanding of the molecular mechanism by which IgG BCRs enhance antibody responses is incomplete. Here, we showed that the conserved cytoplasmic tail of the IgG BCR, which contains a putative PDZ-binding motif, associated with synapse-associated protein 97 (SAP97), a member of the PDZ domain–containing, membrane-associated guanylate-kinase family of scaffolding molecules that play key roles in controlling receptor density and signal strength at neuronal synapses. We showed that SAP97 accumulated and bound to IgG BCRs in the immune synapses that formed in response to engagement of the B cell with antigen. Knocking down SAP97 in IgG-expressing B cells or mutating the putative PDZ-binding motif in the tail impaired immune synapse formation, the initiation of IgG BCR signaling, and downstream activation of p38 mitogen-activated protein kinase. Thus, heightened B cell memory responses are encoded, in part, by a mechanism that involves SAP97 serving as a scaffolding protein in the IgG BCR immune synapse. PMID:22855505

  8. Type i CD20 antibodies recruit the B cell receptor for complement-dependent lysis of malignant B cells

    DEFF Research Database (Denmark)

    Engelberts, P. J.; Voorhorst, M.; Schuurman, J.

    2016-01-01

    . We hypothesized that CD20 Ab-induced clustering of the IgM or IgG BCR was involved in accessory CDC. Indeed, accessory CDC was consistently observed in B cell lines expressing an IgM BCR and in some cell lines expressing an IgG BCR, but it was absent in BCR- B cell lines. A direct relationship...... between BCR expression and accessory CDC was established by transfecting the BCR into CD20+ cells: OFA-F(ab')2 fragments were able to induce CDC in the CD20+BCR+ cell population, but not in the CD20+BCR- population. Importantly, OFA-F(ab')2 fragments were able to induce CDC ex vivo in malignant B cells...... isolated from patients with mantle cell lymphoma and Waldenström macroglobulinemia. In summary, accessory CDC represents a novel effector mechanism that is dependent on type I CD20 Ab-induced BCR clustering. Accessory CDC may contribute to the excellent capacity of type I CD20 Abs to induce CDC...

  9. Studies on Multifunctional Effect of All-Trans Retinoic Acid (ATRA on Matrix Metalloproteinase-2 (MMP-2 and Its Regulatory Molecules in Human Breast Cancer Cells (MCF-7

    Directory of Open Access Journals (Sweden)

    Anindita Dutta

    2009-01-01

    Full Text Available Background. Vitamin A derivative all-trans retinoic acid (ATRA is considered as a potent chemotherapeutic drug for its capability of regulating cell growth and differentiation. We studied the effect of ATRA on MMP-2 in MCF-7, human breast cancer cells, and the probable signaling pathways which are affected by ATRA on regulating pro-MMP-2 activity and expression. Methods. Gelatin zymography, RT-PCR, ELISA, Western blot, Immunoprecipitation, and Cell adhesion assay are used. Results. Gelatin zymography showed that ATRA caused a dose-dependent inhibition of pro-MMP-2 activity. ATRA treatment downregulates the expression of MT1-MMP, EMMPRIN, FAK, NF-kB, and p-ERK. However, expression of E-cadherin, RAR, and CRABP increased upon ATRA treatment. Binding of cells to extra cellular matrix (ECM protein fibronectin reduced significantly after ATRA treatment. Conclusions. The experimental findings clearly showed the inhibition of MMP-2 activity upon ATRA treatment. This inhibitory effect of ATRA on MMP-2 activity in human breast cancer cells (MCF-7 may result due to its inhibitory effect on MT1-MMP, EMMPRIN, and upregulation of TIMP-2. This study is focused on the effect of ATRA on MMP, MMP-integrin-E-cadherin interrelationship, and also the effect of the drug on different signaling molecules which may involve in the progression of malignant tumor development.

  10. Activin A and its regulatory molecules in placenta and fetal membranes of women with preterm premature rupture of the membranes associated with acute chorioamnionitis.

    Science.gov (United States)

    Torricelli, Michela; Voltolini, Chiara; Novembri, Romina; Bocchi, Caterina; Di Tommaso, Mariarosaria; Severi, Filiberto M; Petraglia, Felice

    2012-11-01

    LABELED PROBLEM: To investigate regulation of activin A and related molecules in placenta/fetal membranes from preterm premature rupture of membranes (pPROM) associated with acute chorioamnionitis (ACA). Tissues were obtained from women with spontaneous preterm deliveries (PTD), pPROM without ACA, pPROM with ACA. Activin A, follistatin, and nodal and cripto mRNA were measured by RT-PCR. Activin A mRNA was up-regulated in tissues from pPROM, in presence or absence of HCA, respect to PTD and in pPROM with ACA respect to pPROM without ACA. Follistatin mRNA expression did not differ between the groups. In placenta, nodal mRNA showed the same trend of activin A, while cripto was down-regulated in pPROM with ACA than other groups. Nodal and cripto were not expressed by fetal membranes. The study shows the involvement of activin A pathway in pPROM with ACA. Further studies will focus on its role in placental immune functions. © 2012 John Wiley & Sons A/S.

  11. Coupling of aggregation and immunogenicity in biotherapeutics: T- and B-cell immune epitopes may contain aggregation-prone regions.

    Science.gov (United States)

    Kumar, Sandeep; Singh, Satish K; Wang, Xiaoling; Rup, Bonita; Gill, Davinder

    2011-05-01

    Biotherapeutics, including recombinant or plasma-derived human proteins and antibody-based molecules, have emerged as an important class of pharmaceuticals. Aggregation and immunogenicity are among the major bottlenecks during discovery and development of biotherapeutics. Computational tools that can predict aggregation prone regions as well as T- and B-cell immune epitopes from protein sequence and structure have become available recently. Here, we describe a potential coupling between aggregation and immunogenicity: T-cell and B-cell immune epitopes in therapeutic proteins may contain aggregation-prone regions. The details of biological mechanisms behind this observation remain to be understood. However, our observation opens up an exciting potential for rational design of de-immunized novel, as well as follow on biotherapeutics with reduced aggregation propensity.

  12. 2B4-SAP signaling is required for the priming of naive CD8+ T cells by antigen-expressing B cells and B lymphoma cells

    Science.gov (United States)

    2017-01-01

    ABSTRACT Mutations in SH2D1A gene that encodes SAP (SLAM-associated protein) result in X-linked lymphoproliferative disease (XLP), a rare primary immunodeficiency disease defined by exquisite sensitivity to the B-lymphotropic Epstein–Barr virus (EBV) and B cell lymphomas. However, the precise mechanism of how the loss of SAP function contributes to extreme vulnerability to EBV and the development of B cell lymphomas remains unclear. Here, we investigate the hypothesis that SAP is critical for CD8+ T cell immune surveillance of antigen (Ag)-expressing B cells or B lymphoma cells under conditions of defined T cell receptor (TCR) signaling. Sh2d1a−/− CD8+ T cells exhibited greatly diminished proliferation relative to wild type when Ag-presenting-B cells or -B lymphoma cells served as the primary Ag-presenting cell (APC). By contrast, Sh2d1a−/− CD8+ T cells responded equivalently to wild-type CD8+ T cells when B cell-depleted splenocytes, melanoma cells or breast carcinoma cells performed Ag presentation. Through application of signaling lymphocyte activation molecule (SLAM) family receptor blocking antibodies or SLAM family receptor-deficient CD8+ T cells and APCs, we found that CD48 engagement on the B cell surface by 2B4 is crucial for initiating SAP-dependent signaling required for the Ag-driven CD8+ T cell proliferation and differentiation. Altogether, a pivotal role for SAP in promoting the expansion and differentiation of B cell-primed viral-specific naive CD8+ T cells may explain the selective immune deficiency of XLP patients to EBV and B cell lymphomas. PMID:28344876

  13. 2B4-SAP signaling is required for the priming of naive CD8+ T cells by antigen-expressing B cells and B lymphoma cells.

    Science.gov (United States)

    Huang, Yu-Hsuan; Tsai, Kevin; Tan, Sara Y; Kang, Sohyeong; Ford, Mandy L; Harder, Kenneth W; Priatel, John J

    2017-01-01

    Mutations in SH2D1A gene that encodes SAP (SLAM-associated protein) result in X-linked lymphoproliferative disease (XLP), a rare primary immunodeficiency disease defined by exquisite sensitivity to the B-lymphotropic Epstein-Barr virus (EBV) and B cell lymphomas. However, the precise mechanism of how the loss of SAP function contributes to extreme vulnerability to EBV and the development of B cell lymphomas remains unclear. Here, we investigate the hypothesis that SAP is critical for CD8 + T cell immune surveillance of antigen (Ag)-expressing B cells or B lymphoma cells under conditions of defined T cell receptor (TCR) signaling. Sh2d1a - / - CD8 + T cells exhibited greatly diminished proliferation relative to wild type when Ag-presenting-B cells or -B lymphoma cells served as the primary Ag-presenting cell (APC). By contrast, Sh2d1a - / - CD8 + T cells responded equivalently to wild-type CD8 + T cells when B cell-depleted splenocytes, melanoma cells or breast carcinoma cells performed Ag presentation. Through application of signaling lymphocyte activation molecule (SLAM) family receptor blocking antibodies or SLAM family receptor-deficient CD8 + T cells and APCs, we found that CD48 engagement on the B cell surface by 2B4 is crucial for initiating SAP-dependent signaling required for the Ag-driven CD8 + T cell proliferation and differentiation. Altogether, a pivotal role for SAP in promoting the expansion and differentiation of B cell-primed viral-specific naive CD8 + T cells may explain the selective immune deficiency of XLP patients to EBV and B cell lymphomas.

  14. B-cell activation with CD40L or CpG measures the function of B-cell subsets and identifies specific defects in immunodeficient patients.

    Science.gov (United States)

    Marasco, Emiliano; Farroni, Chiara; Cascioli, Simona; Marcellini, Valentina; Scarsella, Marco; Giorda, Ezio; Piano Mortari, Eva; Leonardi, Lucia; Scarselli, Alessia; Valentini, Diletta; Cancrini, Caterina; Duse, Marzia; Grimsholm, Ola; Carsetti, Rita

    2017-01-01

    Around 65% of primary immunodeficiencies are antibody deficiencies. Functional tests are useful tools to study B-cell functions in vitro. However, no accepted guidelines for performing and evaluating functional tests have been issued yet. Here, we report our experience on the study of B-cell functions in infancy and throughout childhood. We show that T-independent stimulation with CpG measures proliferation and differentiation potential of memory B cells. Switched memory B cells respond better than IgM memory B cells. On the other hand, CD40L, a T-dependent stimulus, does not induce plasma cell differentiation, but causes proliferation of naïve and memory B cells. During childhood, the production of plasmablasts in response to CpG increases with age mirroring the development of memory B cells. The response to CD40L does not change with age. In patients with selective IgA deficiency (SIgAD), we observed that switched memory B cells are reduced due to the absence of IgA memory B cells. In agreement, IgA plasma cells are not generated in response to CpG. Unexpectedly, B cells from SIgAD patients show a reduced proliferative response to CD40L. Our results demonstrate that functional tests are an important tool to assess the functions of the humoral immune system. © 2016 The Authors. European Journal of Immunology published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Intrinsic Plasma Cell Differentiation Defects in B Cell Expansion with NF-κB and T Cell Anergy Patient B Cells

    Directory of Open Access Journals (Sweden)

    Swadhinya Arjunaraja

    2017-08-01

    Full Text Available B cell Expansion with NF-κB and T cell Anergy (BENTA disease is a novel B cell lymphoproliferative disorder caused by germline, gain-of-function mutations in the lymphocyte scaffolding protein CARD11, which drives constitutive NF-κB signaling. Despite dramatic polyclonal expansion of naive and immature B cells, BENTA patients also present with signs of primary immunodeficiency, including markedly reduced percentages of class-switched/memory B cells and poor humoral responses to certain vaccines. Using purified naive B cells from our BENTA patient cohort, here we show that BENTA B cells exhibit intrinsic defects in B cell differentiation. Despite a profound in vitro survival advantage relative to normal donor B cells, BENTA patient B cells were severely impaired in their ability to differentiate into short-lived IgDloCD38hi plasmablasts or CD138+ long-lived plasma cells in response to various stimuli. These defects corresponded with diminished IgG antibody production and correlated with poor induction of specific genes required for plasma cell commitment. These findings provide important mechanistic clues that help explain both B cell lymphocytosis and humoral immunodeficiency in BENTA disease.

  16. Diffuse large B-cell lymphoma of the oral cavity

    International Nuclear Information System (INIS)

    Carlos Bortoluzzi, Marcelo

    2010-01-01

    The authors report a case of diffuse large B-cell lymphoma (DLBL) of the oral cavity. The patient was a 73-year-old white man who first presented at the Division of Stomatology with a large nodular mass in the hard palate and a nodular lesion in the upper lip, which were diagnosed as DLBL. The patient was treated with eight cycles of CHOP chemotherapy (cyclophosphamide, doxorubicin, vincristine and prednisone), but the disease recurred 22 months after the end of the therapy. Both primary sites hard palate and upper lip were involved again and the patient was resubmitted to chemotherapy. (author)

  17. B cell markers in Ph1-positive acute lymphoblastic leukemia.

    Science.gov (United States)

    Alimena, G; De Rossi, G; Gastaldi, R; Guglielmi, C; Mandelli, F

    1980-01-01

    A case of acute lymphoblastic leukemia (ALL) where the blast cells had B cell markers and displayed the presence of a typical Ph1 chromosome, originated by a standard t (9;22) translocation, is reported. Cytological and clinical aspects during the entire course of the disease were consistent with the diagnosis of ALL. Evidence of differentiation along a well-defined lymphoid cell line in a Ph1-positive cell confirms the presence of the Ph1 chromosome in conditions other than chronic granulocytic leukemia and shows that it possibly does not occur in an exclusively undifferentiated totipotent stem cell.

  18. MicroRNA-125b-1 and BLID upregulation resulting from a novel IGH translocation in childhood B-Cell precursor acute lymphoblastic leukemia.

    Science.gov (United States)

    Tassano, Elisa; Acquila, Maura; Tavella, Elisa; Micalizzi, Concetta; Panarello, Claudio; Morerio, Cristina

    2010-08-01

    Chromosomal translocations involving the immunoglobulin heavy chain (IGH) locus are common abnormalities in mature B-cell neoplasms. Recent findings have also revealed their significant role in B-cell precursor acute lymphoblastic leukemia. As a rule, IGH translocations generate transcriptional activation of the oncogene localized in the proximity of the breakpoint. In this study, we describe a pediatric case of B-cell precursor acute lymphoblastic leukemia showing microRNA-125b-1 (MIR125B1) and BLID gene overexpression, resulting from a novel t(11;14)(q24.1;q32) translocation involving IGH. This is the first report describing the upregulation of a microRNA due to its juxtaposition to protein-coding gene regulatory elements and the overexpression of two neighboring genes as a consequence of transcriptional enhancers localized in the vicinity of the IGH gene.

  19. CD47 limits antibody dependent phagocytosis against non-malignant B cells.

    Science.gov (United States)

    Gallagher, Sandra; Turman, Sean; Lekstrom, Kristen; Wilson, Susan; Herbst, Ronald; Wang, Yue

    2017-05-01

    Recent studies have demonstrated the importance of CD47 in protecting malignant B cells from antibody dependent cellular phagocytosis (ADCP). Combined treatment of anti-CD47 and -CD20 antibodies synergistically augment elimination of tumor B cells in xenograft mouse models. This has led to the development of novel reagents that can potentially enhance killing of malignant B cells in patients. B cell depleting therapy is also a promising treatment for autoimmune patients. In the current study, we aimed to investigate whether or not CD47 protects non-malignant B cells from ADCP. We show that CD47 is expressed on all B cells in mice, with the highest level on plasma cells in bone marrow and spleen. Although its expression is dispensable for B cell development in mice, CD47 on B cells limits antibody mediated phagocytosis. B cell depletion following in vivo anti-CD19 treatment is more efficient in CD47-/- mice than in wild type mice. In vitro, both naïve and activated B cells from CD47-/- mice are more sensitive to ADCP than wild type B cells. Lastly, we show in an ADCP assay that blocking CD47 can enhance anti-CD19 antibody mediated phagocytosis of wild type B cells. These results suggest that in addition to its already demonstrated benefit in cancer, targeting CD47 may be used as an adjunct in combination with B cell depletion antibodies for treatment of autoimmune diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Epstein-Barr nuclear antigen 1 induces expression of the cellular microRNA hsa-miR-127 and impairing B-cell differentiation in EBV-infected memory B cells. New insights into the pathogenesis of Burkitt lymphoma

    International Nuclear Information System (INIS)

    Onnis, A; Navari, M; Antonicelli, G; Morettini, F; Mannucci, S; De Falco, G; Vigorito, E; Leoncini, L

    2012-01-01

    Epstein-Barr Virus (EBV) is a γ-herpesvirus that infects >90% of the human population. Although EBV persists in its latent form in healthy carriers, the virus is also associated with several human cancers. EBV is strongly associated with Burkitt lymphoma (BL), even though there is still no satisfactory explanation of how EBV participates in BL pathogenesis. However, new insights into the interplay between viruses and microRNAs (miRNAs) have recently been proposed. In particular, it has been shown that B-cell differentiation in EBV-positive BL is impaired at the post-transcriptional level by altered expression of hsa-miR-127. Here, we show that the overexpression of hsa-miR-127 is due to the presence of the EBV-encoded nuclear antigen 1 (EBNA1) and give evidence of a novel mechanism of direct regulation of the human miRNA by this viral product. Finally, we show that the combinatorial expression of EBNA1 and hsa-miR-127 affects the expression of master B-cell regulators in human memory B cells, confirming the scenario previously observed in EBV-positive BL primary tumors and cell lines. A good understanding of these mechanisms will help to clarify the complex regulatory networks between host and pathogen, and favor the design of more specific treatments for EBV-associated malignancies

  1. B-Cell Activation and Tolerance Mediated by B-Cell Receptor, Toll-Like Receptor, and Survival Signal Crosstalk in SLE Pathogenesis

    Science.gov (United States)

    2017-09-01

    Dec, 2016 "Integrating innate , adaptive, & survival signals to control B cell selection, homeostasis and tolerance" Pasteur Institute of Shanghai...secondary lymphoid tissues. Aging Dis. 2: 361–373. 8. Goenka, R., J. L. Scholz, M. S. Naradikian, and M. P. Cancro. 2014. Memory B cells form in aged...Scholz, and M. P. Cancro. 2011. A B- cell subset uniquely responsive to innate stimuli accumulates in aged mice. Blood 118: 1294–1304. 10. Rubtsov, A

  2. Gaucher disease and comorbidities: B-cell malignancy and parkinsonism.

    Science.gov (United States)

    Cox, Timothy M; Rosenbloom, Barry E; Barker, Roger A

    2015-07-01

    Data emerging from the International Collaborative Gaucher Group (ICGG) Gaucher Registry together with other contemporary clinical surveys have revealed a close association between Gaucher disease and non-Hodgkin's B-cell lymphoma and myeloma and Gaucher disease and Parkinson's disease. Several possible explanations for increased B-cell proliferation and neoplasia in Gaucher disease have been proposed, including the possible influence of sphingosine (derived from the extra lysosomal metabolism of glucosylceramide), gene modifiers, splenectomy and immune system deregulation induced by cytokines, chemokines, and hydrolases released from Gaucher cells. Parkinson's disease is frequently seen in the otherwise-healthy relatives of Gaucher disease patients leading to the finding that GBA mutations represent a genetic risk factor for Parkinson's disease. The mechanism of the association between GBA mutations and Parkinson's disease has yet to be elucidated but the pathogenesis appears distinct from that of Gaucher disease. Several pathogenic pathways have been proposed including lysosomal and/or mitochondrial dysfunction. The effect of Gaucher disease specific therapies on the incidence of cancer or Parkinson's disease are not clear and will likely be evaluated in future ICGG Gaucher Registry studies. © 2015 Wiley Periodicals, Inc.

  3. Bcl-2 antisense therapy in B-cell malignancies.

    Science.gov (United States)

    Chanan-Khan, Asher

    2005-07-01

    Bcl-2 is an apoptosis regulating protein, overexpression of which is associated with chemotherapy resistant disease, aggressive clinical course, and poor survival in patients with B-cell lymphoproliferative disorders. Overexpression of Bcl-2 protein results in an aberrant intrinsic apoptotic pathway that confers a protective effect on malignant cells against a death signal (e.g., chemotherapy or radiotherapy). Downregulation of this oncoprotein, thus, represents a possible new way to target clinically aggressive disease. Preclinical studies have shown that this oncoprotein can be effectively decreased by Bcl-2 antisense in malignant lymphoid cells and can reverse chemotherapy resistance, as well as enhance the anti-apoptotic potential of both chemotherapeutic and biologic agents. Ongoing clinical trials are exploring the role of Bcl-2 downregulation with oblimersen (Bcl-2 antisense) in patients with non-Hodgkin's lymphoma, chronic lymphocytic leukemia and multiple myeloma. Early results from these studies are promising and support the proof of the principle. As these studies are completed and mature data emerges, the role of Bcl-2 antisense therapy in the treatment of B-cell malignancies will become clearer.

  4. Towards the generation of B-cell receptor retrogenic mice.

    Directory of Open Access Journals (Sweden)

    Jenny Freitag

    Full Text Available Transgenic expression of B- and T-cell receptors (BCRs and TCRs, respectively has been a standard tool to study lymphocyte development and function in vivo. The generation of transgenic mice is time-consuming and, therefore, a faster method to study the biology of defined lymphocyte receptors in vivo would be highly welcome. Using 2A peptide-linked multicistronic retroviral vectors to transduce stem cells, TCRs can be expressed rapidly in mice of any background. We aimed at adopting this retrogenic technology to the in vivo expression of BCRs. Using a well characterised BCR specific for hen egg lysozyme (HEL, we achieved surface expression of the retrogenically encoded BCR in a Rag-deficient pro B-cell line in vitro. In vivo, retrogenic BCRs were detectable only intracellularly but not on the surface of B cells from wild type or Rag2-deficient mice. This data, together with the fact that no BCR retrogenic mouse model has been published in the 7 years since the method was originally published for TCRs, strongly suggests that achieving BCR-expression in vivo with retrogenic technology is highly challenging if not impossible.

  5. Primary intravascular large B-cell lymphoma of pituitary

    Directory of Open Access Journals (Sweden)

    K R Anila

    2012-01-01

    Full Text Available A 68-year-old retired nurse, who was a known hypertensive on medication, presented with prolonged fever of 2-month duration without any clinical evidence of infection. On examination she had altered mental status. She also had other nonspecific complaints such as sleep disturbances, loss of weight, etc. On investigation, she was found to have anemia, thrombocytopenia, raised erythrocyte sedimentation rate (ESR, C-reactive protein (CRP, and lactate dehydrogenase (LDH values. She also had electrolyte imbalance. Radiological evaluation of brain showed mass lesion in the sella turcica, suggestive of pituitary adenoma. Biochemical evaluation showed hypopituitarism. Trans-sphenoidal biopsy was done. Based on histopathological and immunohistochemical findings a diagnosis of intravascular large B-cell lymphoma (IVLBCL of pituitary was made. Our patient′s condition deteriorated rapidly and she succumbed to her illness before therapy could be initiated. We are reporting this case because of the rare subtype of large B-cell lymphoma presenting at an extremely unusual primary site.

  6. Modulation of B-cell receptor and microenvironment signaling by a guanine exchange factor in B-cell malignancies

    International Nuclear Information System (INIS)

    Liao, Wei; Sharma, Sanjai

    2016-01-01

    Objective: Chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL) cells over-express a guanine exchange factor (GEF), Rasgrf-1. This GEF increases active Ras as it catalyzes the removal of GDP from Ras so that GTP can bind and activate Ras. This study aims to study the mechanism of action of Rasgrf-1 in B-cell malignancies. Methods: N-terminus truncated Rasgrf-1 variants have a higher GEF activity as compared to the full-length transcript therefore a MCL cell line with stable over-expression of truncated Rasgrf-1 was established. The B-cell receptor (BCR) and chemokine signaling pathways were compared in the Rasgrf-1 over-expressing and a control transfected cell line. Results: Cells over-expressing truncated form of Rasgrf-1 have a higher proliferative rate as compared to control transfected cells. BCR was activated by lower concentrations of anti-IgM antibody in Rasgrf-1 over-expressing cells as compared to control cells indicating that these cells are more sensitive to BCR signaling. BCR signaling also phosphorylates Rasgrf-1 that further increases its GEF function and amplifies BCR signaling. This activation of Rasgrf-1 in over-expressing cells resulted in a higher expression of phospho-ERK, AKT, BTK and PKC-alpha as compared to control cells. Besides BCR, Rasgrf-1 over-expressing cells were also more sensitive to microenvironment stimuli as determined by resistance to apoptosis, chemotaxis and ERK pathway activation. Conclusions: This GEF protein sensitizes B-cells to BCR and chemokine mediated signaling and also upregulates a number of other signaling pathways which promotes growth and survival of these cells

  7. Human Cytotoxic T Lymphocytes Form Dysfunctional Immune Synapses with B Cells Characterized by Non-Polarized Lytic Granule Release

    Directory of Open Access Journals (Sweden)

    Anna Kabanova

    2016-04-01

    Full Text Available Suppression of the cytotoxic T cell (CTL immune response has been proposed as one mechanism for immune evasion in cancer. In this study, we have explored the underlying basis for CTL suppression in the context of B cell malignancies. We document that human B cells have an intrinsic ability to resist killing by freshly isolated cytotoxic T cells (CTLs, but are susceptible to lysis by IL-2 activated CTL blasts and CTLs isolated from immunotherapy-treated patients with chronic lymphocytic leukemia (CLL. Impaired killing was associated with the formation of dysfunctional non-lytic immune synapses characterized by the presence of defective linker for activation of T cells (LAT signaling and non-polarized release of the lytic granules transported by ADP-ribosylation factor-like protein 8 (Arl8. We propose that non-lytic degranulation of CTLs are a key regulatory mechanism of evasion through which B cells may interfere with the formation of functional immune synapses by CTLs.

  8. Dual-reactive B cells are autoreactive and highly enriched in the plasmablast and memory B cell subsets of autoimmune mice

    Science.gov (United States)

    Fournier, Emilie M.; Velez, Maria-Gabriela; Leahy, Katelyn; Swanson, Cristina L.; Rubtsov, Anatoly V.; Torres, Raul M.

    2012-01-01

    Rare dual-reactive B cells expressing two types of Ig light or heavy chains have been shown to participate in immune responses and differentiate into IgG+ cells in healthy mice. These cells are generated more often in autoreactive mice, leading us to hypothesize they might be relevant in autoimmunity. Using mice bearing Igk allotypic markers and a wild-type Ig repertoire, we demonstrate that the generation of dual-κ B cells increases with age and disease progression in autoimmune-prone MRL and MRL/lpr mice. These dual-reactive cells express markers of activation and are more frequently autoreactive than single-reactive B cells. Moreover, dual-κ B cells represent up to half of plasmablasts and memory B cells in autoimmune mice, whereas they remain infrequent in healthy mice. Differentiation of dual-κ B cells into plasmablasts is driven by MRL genes, whereas the maintenance of IgG+ cells is partly dependent on Fas inactivation. Furthermore, dual-κ B cells that differentiate into plasmablasts retain the capacity to secrete autoantibodies. Overall, our study indicates that dual-reactive B cells significantly contribute to the plasmablast and memory B cell populations of autoimmune-prone mice suggesting a role in autoimmunity. PMID:22927551

  9. Pregnancy alters the circulating B cell compartment in atopic asthmatic women, and transitional B cells are positively associated with the development of allergy manifestations in their progeny.

    Science.gov (United States)

    Martins, Catarina; Lima, Jorge; Nunes, Glória; Borrego, Luís Miguel

    2016-12-01

    Maternal atopy is a risk factor for allergy. B cells are poorly studied in reproduction and atopy. We aimed to assess how pregnancy affects B cells in atopic women and whether B cells relate to allergic manifestations in offspring. Women with and without atopic asthma, pregnant and non-pregnant were enrolled for the study, and circulating B cells were evaluated by flow cytometry, using CD19, CD27, CD38, IgD, and IgM. Compared to healthy non-pregnant, atopic asthmatic non-pregnant (ANP) women presented increased B cell counts, enlarged memory subsets, less transitional cells, and plasmablasts. Atopic asthmatic pregnant (AP) and healthy pregnant (HP) women showed similarities: reduced B cell counts and percentages, fewer memory cells, especially switched, and higher plasmablast percentages. Transitional B cell percentages were increased in AP women with allergic manifestations in their progeny. Atopic asthmatic non-pregnant women have a distinctive B cell compartment. B cells change in pregnancy, similarly in AP and HP women. The recognition that AP women with allergy in their progeny have a typical immune profile may help, in the future, the adoption of preventive measures to avoid the manifestation of allergic diseases in their newborns. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. B-cell subset alterations and correlated factors in HIV-1 infection.

    Science.gov (United States)

    Pensieroso, Simone; Galli, Laura; Nozza, Silvia; Ruffin, Nicolas; Castagna, Antonella; Tambussi, Giuseppe; Hejdeman, Bo; Misciagna, Donatella; Riva, Agostino; Malnati, Mauro; Chiodi, Francesca; Scarlatti, Gabriella

    2013-05-15

    During HIV-1 infection, the development, phenotype, and functionality of B cells are impaired. Transitional B cells and aberrant B-cell populations arise in blood, whereas a declined percentage of resting memory B cells is detected. Our study aimed at pinpointing the demographic, immunological, and viral factors driving these pathological findings, and the role of antiretroviral therapy in reverting these alterations. B-cell phenotype and correlating factors were evaluated. Variations in B-cell subsets were evaluated by flow cytometry in HIV-1-infected individuals naive to therapy, elite controllers, and patients treated with antiretroviral drugs (virological control or failure). Multivariable analysis was performed to identify variables independently associated with the B-cell alterations. Significant differences were observed among patients' groups in relation to all B-cell subsets. Resting memory B cells were preserved in patients naive to therapy and elite controllers, but reduced in treated patients. Individuals naive to therapy and experiencing multidrug failure, as well as elite controllers, had significantly higher levels of activated memory B cells compared to healthy controls. In the multivariate analysis, plasma viral load and nadir CD4 T cells independently correlated with major B-cell alterations. Coinfection with hepatitis C but not hepatitis B virus also showed an impact on specific B-cell subsets. Successful protracted antiretroviral treatment led to normalization of all B-cell subsets with exception of resting memory B cells. Our results indicate that viremia and nadir CD4 T cells are important prognostic markers of B-cell perturbations and provide evidence that resting memory B-cell depletion during chronic infection is not reverted upon successful antiretroviral therapy.

  11. Molecule nanoweaver

    Science.gov (United States)

    Gerald, II; Rex, E [Brookfield, IL; Klingler, Robert J [Glenview, IL; Rathke, Jerome W [Homer Glen, IL; Diaz, Rocio [Chicago, IL; Vukovic, Lela [Westchester, IL

    2009-03-10

    A method, apparatus, and system for constructing uniform macroscopic films with tailored geometric assemblies of molecules on the nanometer scale. The method, apparatus, and system include providing starting molecules of selected character, applying one or more force fields to the molecules to cause them to order and condense with NMR spectra and images being used to monitor progress in creating the desired geometrical assembly and functionality of molecules that comprise the films.

  12. Cell- and stage-specific chromatin structure across the Complement receptor 2 (CR2/CD21) promoter coincide with CBF1 and C/EBP-beta binding in B cells.

    Science.gov (United States)

    Cruickshank, Mark N; Fenwick, Emily; Karimi, Mahdad; Abraham, Lawrence J; Ulgiati, Daniela

    2009-08-01

    Stringent developmental transcription requires multiple transcription factor (TF) binding sites, cell-specific expression of signaling molecules, TFs and co-regulators and appropriate chromatin structure. During B-lymphopoiesis, human Complement receptor 2 (CR2/CD21) is detected on immature and mature B cells but not on B cell precursors and plasma cells. We examined cell- and stage-specific human CR2 gene regulation using cell lines modeling B-lymphopoiesis. Chromatin accessibility assays revealed a region between -409 and -262 with enhanced accessibility in mature B cells and pre-B cells, compared to either non-lymphoid or plasma cell-types, however, accessibility near the transcription start site (TSS) was elevated only in CR2-expressing B cells. A correlation between histone acetylation and CR2 expression was observed, while histone H3K4 dimethylation was enriched near the TSS in both CR2-expressing B cells and non-expressing pre-B cells. Candidate sites within the CR2 promoter were identified which could regulate chromatin, including a matrix attachment region associated with CDP, SATB1/BRIGHT and CEBP-beta sites as well as two CBF1 sites. ChIP assays verified that both CBF1 and C/EBP-beta bind the CR2 promoter in B cells raising the possibility that these factors facilitate or respond to alterations in chromatin structure to control the timing and/or level of CR2 transcription.

  13. Cigarette smoke-induced emphysema : A role for the B cell?

    NARCIS (Netherlands)

    van der Strate, BWA; Postma, DS; Brandsma, CA; Melgert, BN; Luinge, MA; Geerlings, M; Hylkema, MN; van den Berg, Anke; Timens, W; Kerstjens, HAM

    2006-01-01

    Rationale: Little is known about what drives the inflammatory reaction in the development of chronic obstructive lung disease. B cells have been found. Objective: To study the involvement of B cells in the development of emphysema. Methods: The presence of B-cell follicles and their interaction with

  14. Monovalent engagement of the BCR activates ovalbumin-specific transnuclear B cells

    NARCIS (Netherlands)

    Avalos, Ana M.; Bilate, Angelina M.; Witte, Martin D.; Tai, Albert K.; He, Jiang; Frushicheva, Maria P.; Thill, Peter D.; Meyer-Wentrup, Friederike; Theile, Christopher S.; Chakraborty, Arup K.; Zhuang, Xiaowei; Ploegh, Hidde L.

    2014-01-01

    Valency requirements for B cell activation upon antigen encounter are poorly understood. OB1 transnuclear B cells express an IgG1 B cell receptor (BCR) specific for ovalbumin (OVA), the epitope of which can be mimicked using short synthetic peptides to allow antigen-specific engagement of the BCR.

  15. File list: ALL.Bld.05.AllAg.Lymphoma,_B-Cell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Bld.05.AllAg.Lymphoma,_B-Cell hg19 All antigens Blood Lymphoma, B-Cell SRX37034...351,SRX092415,SRX370350,SRX092417,SRX092414 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Bld.05.AllAg.Lymphoma,_B-Cell.bed ...

  16. File list: ALL.Bld.50.AllAg.Lymphoma,_B-Cell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Bld.50.AllAg.Lymphoma,_B-Cell hg19 All antigens Blood Lymphoma, B-Cell SRX37034...349,SRX370351,SRX370345,SRX092415,SRX092417 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Bld.50.AllAg.Lymphoma,_B-Cell.bed ...

  17. File list: His.Bld.10.AllAg.Lymphoma,_B-Cell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bld.10.AllAg.Lymphoma,_B-Cell hg19 Histone Blood Lymphoma, B-Cell SRX370346,SRX...370340,SRX370344,SRX370342,SRX370348,SRX370350 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Bld.10.AllAg.Lymphoma,_B-Cell.bed ...

  18. File list: His.Bld.50.AllAg.Lymphoma,_B-Cell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bld.50.AllAg.Lymphoma,_B-Cell hg19 Histone Blood Lymphoma, B-Cell SRX370346,SRX...370350,SRX370344,SRX370342,SRX370348,SRX370340 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Bld.50.AllAg.Lymphoma,_B-Cell.bed ...

  19. File list: Oth.Bld.50.AllAg.Lymphoma,_B-Cell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Bld.50.AllAg.Lymphoma,_B-Cell hg19 TFs and others Blood Lymphoma, B-Cell SRX092...416,SRX092414 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Bld.50.AllAg.Lymphoma,_B-Cell.bed ...

  20. File list: Oth.Bld.20.AllAg.Lymphoma,_B-Cell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Bld.20.AllAg.Lymphoma,_B-Cell hg19 TFs and others Blood Lymphoma, B-Cell SRX092...416,SRX092414 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Bld.20.AllAg.Lymphoma,_B-Cell.bed ...

  1. File list: Oth.Bld.05.AllAg.Lymphoma,_B-Cell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Bld.05.AllAg.Lymphoma,_B-Cell hg19 TFs and others Blood Lymphoma, B-Cell SRX092...416,SRX092414 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Bld.05.AllAg.Lymphoma,_B-Cell.bed ...

  2. File list: ALL.Bld.10.AllAg.Lymphoma,_B-Cell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Bld.10.AllAg.Lymphoma,_B-Cell hg19 All antigens Blood Lymphoma, B-Cell SRX37034...416,SRX092414,SRX370350,SRX092417,SRX092415 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Bld.10.AllAg.Lymphoma,_B-Cell.bed ...

  3. File list: His.Bld.05.AllAg.Lymphoma,_B-Cell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bld.05.AllAg.Lymphoma,_B-Cell hg19 Histone Blood Lymphoma, B-Cell SRX370346,SRX...370344,SRX370340,SRX370342,SRX370348,SRX370350 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Bld.05.AllAg.Lymphoma,_B-Cell.bed ...

  4. File list: Oth.Bld.10.AllAg.Lymphoma,_B-Cell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Bld.10.AllAg.Lymphoma,_B-Cell hg19 TFs and others Blood Lymphoma, B-Cell SRX092...416,SRX092414 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Bld.10.AllAg.Lymphoma,_B-Cell.bed ...

  5. File list: ALL.Bld.20.AllAg.Lymphoma,_B-Cell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Bld.20.AllAg.Lymphoma,_B-Cell hg19 All antigens Blood Lymphoma, B-Cell SRX37034...348,SRX370345,SRX092417,SRX370351,SRX092415 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Bld.20.AllAg.Lymphoma,_B-Cell.bed ...

  6. File list: His.Bld.20.AllAg.Lymphoma,_B-Cell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bld.20.AllAg.Lymphoma,_B-Cell hg19 Histone Blood Lymphoma, B-Cell SRX370346,SRX...370340,SRX370344,SRX370350,SRX370342,SRX370348 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Bld.20.AllAg.Lymphoma,_B-Cell.bed ...

  7. File list: ALL.Bld.20.AllAg.Pro-B_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Bld.20.AllAg.Pro-B_cells mm9 All antigens Blood Pro-B cells SRX1553109,SRX15531...3,SRX1143907 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Bld.20.AllAg.Pro-B_cells.bed ...

  8. File list: His.Bld.50.AllAg.Pro-B_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bld.50.AllAg.Pro-B_cells mm9 Histone Blood Pro-B cells SRX668836,SRX1184113,SRX...09,SRX759800,SRX1143916,SRX1143902 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Bld.50.AllAg.Pro-B_cells.bed ...

  9. File list: His.Bld.20.AllAg.Pro-B_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Bld.20.AllAg.Pro-B_cells mm9 Histone Blood Pro-B cells SRX668836,SRX1184113,SRX...9,SRX1143910,SRX1143916,SRX1143902 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Bld.20.AllAg.Pro-B_cells.bed ...

  10. Murine gammaherpesvirus M2 protein induction of IRF4 via the NFAT pathway leads to IL-10 expression in B cells.

    Directory of Open Access Journals (Sweden)

    Udaya S Rangaswamy

    2014-01-01

    Full Text Available Reactivation of the gammaherpesviruses Epstein-Barr virus (EBV, Kaposi's sarcoma-associated herpesvirus (KSHV and murine gammaherpesvirus 68 (MHV68 from latently infected B cells has been linked to plasma cell differentiation. We have previously shown that the MHV68 M2 protein is important for virus reactivation from B cells and, when expressed alone in primary murine B cells, can drive B cell differentiation towards a pre-plasma cell phenotype. In addition, expression of M2 in primary murine B cells leads to secretion of high levels of IL-10 along with enhanced proliferation and survival. Furthermore, the absence of M2 in vivo leads to a defect in the appearance of MHV68 infected plasma cells in the spleen at the peak of MHV68 latency. Here, employing an inducible B cell expression system, we have determined that M2 activates the NFAT pathway in a Src kinase-dependent manner--leading to induction of the plasma cell-associated transcription factor, Interferon Regulatory Factor-4 (IRF4. Furthermore, we show that expression of IRF4 alone in a B cell line up-regulates IL-10 expression in culture supernatants, revealing a novel role for IRF4 in B cell induced IL-10. Consistent with the latter observation, we show that IRF4 can regulate the IL-10 promoter in B cells. In primary murine B cells, addition of cyclosporine (CsA resulted in a significant decrease in M2-induced IL-10 levels as well as IRF4 expression, emphasizing the importance of the NFAT pathway in M2- -mediated induction of IL-10. Together, these studies argue in favor of a model wherein M2 activation of the NFAT pathway initiates events leading to increased levels of IRF4--a key player in plasma cell differentiation--which in turn triggers IL-10 expression. In the context of previous findings, the data presented here provides insights into how M2 facilitates plasma cell differentiation and subsequent virus reactivation.

  11. The A-myb transcription factor in neoplastic and normal B cells.

    Science.gov (United States)

    Golay, J; Facchinetti, V; Ying, G; Introna, M

    1997-07-01

    The myb family of transcription factors has been strongly implicated in the regulation of cell growth and differentiation in the haematopoietic system. The v-myb oncogene, carried by avian defective retroviruses, causes leukaemias in the chicken and transforms haematopoietic cells in vitro. Its normal cellular equivalent c-myb, has been shown to promote the proliferation and block the differentiation of haematopoietic cells in several experimental models and is required for fetal haematopoiesis. Two other members of the family have been cloned more recently, A-myb and B-myb, which show sequence homology with c-myb in several domains, of which the DNA binding domain as well as other regulatory domains. Both have been shown to be transcription factors. B-myb is also involved in the control of proliferation and differentiation, but, unlike c-myb, it is expressed in many cell types. The third member of the family, A-myb, shows the most restricted pattern of expression, suggesting a very specific role for this transcription factor. A-myb is expressed in a subpopulation of normal B lymphocytes activated in vivo and localised in the germinal center of peripheral lymphoid organs and is not detected at significant levels in all other mature or immature haematopoietic populations studied, including bone marrow cells, T lymphocytes, granulocytes, monocytes, either at rest or after in vitro activation. These studies indicate that A-myb plays a role during a narrow window of normal B cell differentiation. A-myb expression has also been studied in a wide range of neoplastic B cells, representing the whole spectrum of B cell differentiation. A-myb is strongly expressed in Burkitt's lymphomas (BL) and slg+ B-acute lymphoblastic leukaemias (B-ALL) and not in all other leukaemias/lymphomas tested, with the exception of a subset of CLL (about 25% of cases). It is intriguing that the A-myb genome has been localised relatively close to the c-myc gene on chromosome 8, suggesting that

  12. Specific blockade by CD54 and MHC II of CD40-mediated signaling for B cell proliferation and survival

    DEFF Research Database (Denmark)

    Doyle, I S; Hollmann, C A; Crispe, I N

    2001-01-01

    Regulation of B lymphocyte proliferation is critical to maintenance of self-tolerance, and intercellular interactions are likely to signal such regulation. Here, we show that coligation of either the adhesion molecule ICAM-1/CD54 or MHC II with CD40 inhibited cell cycle progression and promoted...... these effects. Addition of BCR or IL-4 signals did not overcome the effect of ICAM-1 or MHC II on CD40-induced proliferation. FasL expression was not detected in B cell populations. These results show that MHC II and ICAM-1 specifically modulate CD40-mediated signaling, so inhibiting proliferation...

  13. Maternal and fetal mechanisms of B cell regulation during pregnancy: human Chorionic Gonadotropin stimulates B cells to produce IL-10 while alpha-fetoprotein drives them into apoptosis

    Directory of Open Access Journals (Sweden)

    Franziska Fettke

    2016-12-01

    Full Text Available Maternal immune tolerance towards the fetus is an essential requisite for pregnancy. While T cell functions are well documented, little is known about the participation of B cells. We have previously suggested that IL-10 producing B cells are involved in pregnancy tolerance in mice and humans. By employing murine and human systems, we report now that fetal trophoblasts positively regulate the generation of IL-10 producing B cells. We next studied the participation of hormones produced by the placenta as well as the fetal protein alpha-fetoprotein (AFP in B cell modulation. Human Chorionic Gonadotropin (hCG, but not progesterone, estrogen or a combination of both, was able to promote changes in B cell phenotype and boost their IL-10 production, which was abolished after blocking hCG. The hCG-induced B cell phenotype was not associated with augmented galactosylation, sialylation or fucosylation of IgG subclasses in their Fc. In vitro, hCG induced the synthesis of asymmetrically glycosylated antibodies in their Fab region. Interestingly, AFP had dual effects depending on the concentration. At concentrations corresponding to maternal serum levels, it did not modify the phenotype or IL-10 secretion of B cells. At fetal concentrations, however, AFP was able to drive B cells into apoptosis, which may indicate a protective mechanism to avoid maternal B cells to reach the fetus.Our data suggests that the fetus secrete factors that promote a pregnancy-friendly B cell phenotype, unraveling interesting aspects of B cell function and modulation by pregnancy hormones and fetal proteins.

  14. SAP expression in invariant NKT cells is required for cognate help to support B-cell responses.

    Science.gov (United States)

    Detre, Cynthia; Keszei, Marton; Garrido-Mesa, Natividad; Kis-Toth, Katalin; Castro, Wilson; Agyemang, Amma F; Veerapen, Natacha; Besra, Gurdyal S; Carroll, Michael C; Tsokos, George C; Wang, Ninghai; Leadbetter, Elizabeth A; Terhorst, Cox

    2012-07-05

    One of the manifestations of X-linked lymphoproliferative disease (XLP) is progressive agammaglobulinemia, caused by the absence of a functional signaling lymphocyte activation molecule (SLAM)-associated protein (SAP) in T, invariant natural killer T (NKT) cells and NK cells. Here we report that α-galactosylceramide (αGalCer) activated NKT cells positively regulate antibody responses to haptenated protein antigens at multiple checkpoints, including germinal center formation and affinity maturation. Whereas NKT cell-dependent B cell responses were absent in SAP(-/-).B6 mice that completely lack NKT cells, the small number of SAP-deficient NKT cells in SAP(-/-).BALB/c mice adjuvated antibody production, but not the germinal center reaction. To test the hypothesis that SAP-deficient NKT cells can facilitate humoral immunity, SAP was deleted after development in SAP(fl/fl).tgCreERT2.B6 mice. We find that NKT cell intrinsic expression of SAP is dispensable for noncognate helper functions, but is critical for providing cognate help to antigen-specific B cells. These results demonstrate that SLAM-family receptor-regulated cell-cell interactions are not limited to T-B cell conjugates. We conclude that in the absence of SAP, several routes of NKT cell-mediated antibody production are still accessible. The latter suggests that residual NKT cells in XLP patients might contribute to variations in dysgammaglobulinemia.

  15. Chronic Lymphocytic Leukemia B-Cell Normal Cellular Counterpart: Clues From a Functional Perspective.

    Science.gov (United States)

    Darwiche, Walaa; Gubler, Brigitte; Marolleau, Jean-Pierre; Ghamlouch, Hussein

    2018-01-01

    Chronic lymphocytic leukemia (CLL) is characterized by the clonal expansion of small mature-looking CD19+ CD23+ CD5+ B-cells that accumulate in the blood, bone marrow, and lymphoid organs. To date, no consensus has been reached concerning the normal cellular counterpart of CLL B-cells and several B-cell types have been proposed. CLL B-cells have remarkable phenotypic and gene expression profile homogeneity. In recent years, the molecular and cellular biology of CLL has been enriched by seminal insights that are leading to a better understanding of the natural history of the disease. Immunophenotypic and molecular approaches (including immunoglobulin heavy-chain variable gene mutational status, transcriptional and epigenetic profiling) comparing the normal B-cell subset and CLL B-cells provide some new insights into the normal cellular counterpart. Functional characteristics (including activation requirements and propensity for plasma cell differentiation) of CLL B-cells have now been investigated for 50 years. B-cell subsets differ substantially in terms of their functional features. Analysis of shared functional characteristics may reveal similarities between normal B-cell subsets and CLL B-cells, allowing speculative assignment of a normal cellular counterpart for CLL B-cells. In this review, we summarize current data regarding peripheral B-cell differentiation and human B-cell subsets and suggest possibilities for a normal cellular counterpart based on the functional characteristics of CLL B-cells. However, a definitive normal cellular counterpart cannot be attributed on the basis of the available data. We discuss the functional characteristics required for a cell to be logically considered to be the normal counterpart of CLL B-cells.

  16. T cell-B cell interactions in primary immunodeficiencies.

    Science.gov (United States)

    Tangye, Stuart G; Deenick, Elissa K; Palendira, Umaimainthan; Ma, Cindy S

    2012-02-01

    Regulated interactions between cells of the immune system facilitate the generation of successful immune responses, thereby enabling efficient neutralization and clearance of pathogens and the establishment of both cell- and humoral-mediated immunological memory. The corollary of this is that impediments to efficient cell-cell interactions, normally necessary for differentiation and effector functions of immune cells, underly the clinical features and disease pathogenesis of primary immunodeficiencies. In affected individuals, these defects manifest as impaired long-term humoral immunity and susceptibility to infection by specific pathogens. In this review, we discuss the importance of, and requirements for, effective interactions between B cells and T cells during the formation of CD4(+) T follicular helper cells and the elicitation of cytotoxic function of virus-specific CD8(+) T cells, as well as how these processes are abrogated in primary immunodeficiencies due to loss-of-function mutations in defined genes. © 2012 New York Academy of Sciences.

  17. [Primary cutaneous B-cell lymphomas: study of 22 cases].

    Science.gov (United States)

    Martín Carrasco, Pablo; Morillo Andújar, Mercedes; Pérez Ruiz, Carmen; de Zulueta Dorado, Teresa; Cabrera Pérez, Rocío; Conejo-Mir, Julián

    2016-09-02

    Primary cutaneous B-cell lymphoma (CBCL) is a very low prevalence neoplasm and constitutes 25% of all primary cutaneous lymphomas. Our objective was to discover the epidemiological, clinic and histologic characteristics of CBCL in our area. Retrospective descriptive study with patients with histologic diagnosis of CBCL followed up in our department between 2004 and 2015. Twenty-two patients with CBCL were included; 65% were men and 35% were women. Follicle centre lymphoma was the most common subtype (41%). Only 3 cases presented with node involvement and one with bone marrow invasion. Five recurrences were detected and one patient died because of the CBCL. This is one of the first CBCL series in theSpanish population. The incidence, sex, age, subtype distribution, clinical features and immunohistochemical patterns are very similar to those of the other series. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  18. B Cell Depletion: Rituximab in Glomerular Disease and Transplantation

    Directory of Open Access Journals (Sweden)

    S. Marinaki

    2013-12-01

    Full Text Available B cells play a central role in the pathogenesis of many autoimmune diseases. Selective targeting can be achieved with the use of the monoclonal antibody rituximab. In addition to being a drug for non-Hodgkin's lymphoma, rituximab is also an FDA-approved treatment for refractory rheumatoid arthritis and, since recently, ANCA vasculitis. It has shown efficacy in many autoimmune diseases. This review will discuss current evidence and the rationale of the use of rituximab in glomerular diseases, including randomized controlled trials. The focus will be on the use of rituximab in idiopathic membranous nephropathy, systemic lupus erythematosus and ANCA-associated vasculitis. The emerging role of rituximab in renal transplantation, where it seems to be important for the desensitization protocols for highly sensitized patients as well as for the preconditioning of ABO-incompatible recipients and the treatment of antibody-mediated rejection, will also be addressed.

  19. Cerebral toxoplasmosis in a diffuse large B cell lymphoma patient

    International Nuclear Information System (INIS)

    Savsek, Lina; Opaskar, Tanja Ros

    2016-01-01

    Toxoplasmosis is an opportunistic protozoal infection that has, until now, probably been an underestimated cause of encephalitis in patients with hematological malignancies, independent of stem cell or bone marrow transplant. T and B cell depleting regimens are probably an important risk factor for reactivation of a latent toxoplasma infection in these patients. We describe a 62-year-old HIV-negative right-handed Caucasian female with systemic diffuse large B cell lymphoma who presented with sudden onset of high fever, headache, altered mental status, ataxia and findings of pancytopenia, a few days after receiving her final, 8 th cycle of rituximab, cyclophosphamide, vincristine, doxorubicin, prednisolone (R-CHOP) chemotherapy regimen. A progression of lymphoma to the central nervous system was suspected. MRI of the head revealed multiple on T2 and fluid attenuated inversion recovery (FLAIR) hyperintense parenchymal lesions with mild surrounding edema, located in both cerebral and cerebellar hemispheres that demonstrated moderate gadolinium enhancement. The polymerase chain reaction on cerebrospinal fluid (CSF PCR) was positive for Toxoplasma gondii. The patient was diagnosed with toxoplasmic encephalitis and successfully treated with sulfadiazine, pyrimethamine and folic acid. Due to the need for maintenance therapy with rituximab for lymphoma remission, the patient now continues with secondary prophylaxis of toxoplasmosis. With this case report, we wish to emphasize the need to consider cerebral toxoplasmosis in patients with hematological malignancies on immunosuppressive therapy when presenting with new neurologic deficits. In such patients, there are numerous differential diagnoses for cerebral toxoplasmosis, and the CNS lymphoma is the most difficult among all to distinguish it from. If left untreated, cerebral toxoplasmosis has a high mortality rate; therefore early recognition and treatment are of essential importance

  20. Compartmentalization of B-cell antigen receptor functions

    NARCIS (Netherlands)

    Lankester, A. C.; van Lier, R. A.

    1996-01-01

    Receptor tyrosine kinases (RTK), like the PDGF-receptor, translate information from the extracellular environment into cytoplasmic signals that regulate a spectrum of cellular functions. RTK molecules consist of ligand binding extracellular domains, cytoplasmic kinase domains and tyrosine

  1. B-cell exposure to self-antigen induces IL-10 producing B cells as well as IL-6- and TNF-α-producing B-cell subsets in healthy humans

    DEFF Research Database (Denmark)

    Langkjær, Anina; Kristensen, Birte; Hansen, Bjarke E

    2012-01-01

    Human B cells are able to secrete IL-10 after stimulation with mitogens, but their ability to produce IL-10 and regulate T-cell responses after stimulation with self-antigens is unclear. We co-cultured thyroglobulin-pulsed B cells from healthy donors with autologous T cells and observed production...... of IL-10 and TGF-β, in addition to TNF-α and IL-6. Pulsing with foreign antigen, tetanus toxoid (TT), induced a Th1-response with minimal IL-10 production. After thyroglobulin-pulsing, 1.10±0.50% of B cells and 1.00±0.20% of CD4(+) T cells produced IL-10, compared to 0.29±0.19% of B cells (P=0.01) and 0.......13±0.15% of CD4(+) T cells (P=0.006) following TT-pulsing. Thyroglobulin-stimulated, IL-10-secreting B cells were enriched within CD5(+) and CD24(high) cells. While thyroglobulin-pulsed B cells induced only modest proliferation of CD4(+) T cells, B cells pulsed with TT induced vigorous proliferation. Thus, B...

  2. CD137 is induced by the CD40 signal on chronic lymphocytic leukemia B cells and transduces the survival signal via NF-κB activation.

    Directory of Open Access Journals (Sweden)

    Yukana Nakaima

    Full Text Available CD137 is a member of the tumor necrosis factor receptor family that is expressed on activated T cells. This molecule provides a co-stimulatory signal that enhances the survival, and differentiation of cells, and has a crucial role in the development of CD8 cytotoxic T cells and anti-tumor immunity. Here we report that CD137 expression is also induced on normal or malignant human B cells by CD40 ligation by its ligand CD154. This CD137 induction was more prominent in chronic lymphocytic leukemia (CLL cells than in other types of B cells. CD137 stimulation on B cells by its ligand induced the nuclear translocation of p52 (a non-canonical NF-κB factor. In agreement with this finding, expression of the survival factor BCL-XL was upregulated. Consequently, the CD137 signal augmented the survival of CD154-stimulated CLL B cells in vitro. This unexpected induction of CD137 on B cells by CD40 signal may influence the clinical course of CLL.

  3. Loss of PRDM1/BLIMP-1 function contributes to poor prognosis of activated B-cell-like diffuse large B-cell lymphoma

    DEFF Research Database (Denmark)

    Xia, Yi; Xu-Monette, Z Y; Tzankov, A

    2017-01-01

    PRDM1/BLIMP-1, a master regulator of plasma-cell differentiation, is frequently inactivated in activated B-cell-like (ABC) diffuse large B-cell lymphoma (DLBCL) patients. Little is known about its genetic aberrations and relevant clinical implications. A large series of patients with de novo DLBC...

  4. EBI2 overexpression in mice leads to B1 B-cell expansion and chronic lymphocytic leukemia-like B-cell malignancies.

    Science.gov (United States)

    Niss Arfelt, Kristine; Barington, Line; Benned-Jensen, Tau; Kubale, Valentina; Kovalchuk, Alexander L; Daugvilaite, Viktorija; Christensen, Jan Pravsgaard; Thomsen, Allan Randrup; Egerod, Kristoffer L; Bassi, Maria R; Spiess, Katja; Schwartz, Thue W; Wang, Hongsheng; Morse, Herbert C; Holst, Peter J; Rosenkilde, Mette M

    2017-02-16

    Human and mouse chronic lymphocytic leukemia (CLL) develops from CD5 + B cells that in mice and macaques are known to define the distinct B1a B-cell lineage. B1a cells are characterized by lack of germinal center (GC) development, and the B1a cell population is increased in mice with reduced GC formation. As a major mediator of follicular B-cell migration, the G protein-coupled receptor Epstein-Barr virus-induced gene 2 ( EBI2 or GPR183 ) directs B-cell migration in the lymphoid follicles in response to its endogenous ligands, oxysterols. Thus, upregulation of EBI2 drives the B cells toward the extrafollicular area, whereas downregulation is essential for GC formation. We therefore speculated whether increased expression of EBI2 would lead to an expanded B1 cell subset and, ultimately, progression to CLL. Here, we demonstrate that B-cell-targeted expression of human EBI2 (hEBI2) in mice reduces GC-dependent immune responses, reduces total immunoglobulin M (IgM) and IgG levels, and leads to increased proliferation and upregulation of cellular oncogenes. Furthermore, hEBI2 overexpression leads to an abnormally expanded CD5 + B1a B-cell subset (present as early as 4 days after birth), late-onset lymphoid cancer development, and premature death. These findings are highly similar to those observed in CLL patients and identify EBI2 as a promoter of B-cell malignancies.

  5. Genetic modification of human B-cell development: B-cell development is inhibited by the dominant negative helix loop helix factor Id3

    NARCIS (Netherlands)

    Jaleco, A. C.; Stegmann, A. P.; Heemskerk, M. H.; Couwenberg, F.; Bakker, A. Q.; Weijer, K.; Spits, H.

    1999-01-01

    Transgenic and gene targeted mice have contributed greatly to our understanding of the mechanisms underlying B-cell development. We describe here a model system that allows us to apply molecular genetic techniques to the analysis of human B-cell development. We constructed a retroviral vector with a

  6. The progeny of a single virgin B cell predominates the human recall B cell response to the capsular polysaccharide of Haemophilus influenzae type b

    DEFF Research Database (Denmark)

    Barington, T; Hougs, L; Juul, L

    1996-01-01

    of the cells originated from a common virgin B cell. Kinetic considerations implied that an extremely selected population of hypermutated memory B cells must have existed in these individuals before the first systemic immunization with the Ag. A possible role for the mucosal immune system in the priming...

  7. CD20-based Immunotherapy of B-cell Derived Hematologic Malignancies.

    Science.gov (United States)

    Shanehbandi, Dariush; Majidi, Jafar; Kazemi, Tohid; Baradaran, Behzad; Aghebati-Maleki, Leili

    2017-01-01

    CD20 is a surface antigen, which is expressed at certain stages of B-cell differentiation. Targeting the CD20-positive B-cells with therapeutic monoclonal antibodies (MAbs) has been an effectual strategy in the treatment of hematologic malignancies such as non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL). Initial success with Rituximab (RTX) has encouraged the creation and development of more effective CD20 based therapeutics. However, treatment with conventional MAbs has not been adequate to overcome the problems such as refractory/ relapsed disease. In this regard, new generations of MAbs with enhanced affinity or improved anti-tumor properties have been developed. CD20 directed therapeutics have heterogeneous features and mechanisms of action. Hence, having sufficient knowledge on the immunological and molecular aspects of CD20 based cancer therapy is necessary for predicting the clinical outcomes and taking the necessary measures. An extensive search was performed in PubMed and similar databases for peer-reviewed articles concerning the biology, function and characteristics of CD20 molecule as well as the mechanisms of action and evolutionary process of CD20 targeting agents. This review provides information about the current situation of CD20 targeting immunotherapeutics including MAbs, bispecific antibodies (which exert multiple functions or involve Tcells in tumor elimination) and CAR T-cells (engineered T-cells armed with chimeric antigen receptors). Moreover, limitations, challenges and available solutions regarding the application of CD20 targeting treatments are addressed. Utilization of CD20-targeted therapeutics, due to their diverse properties, requires special considerations. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  8. Plant Hsp90 Proteins Interact with B-Cells and Stimulate Their Proliferation

    Science.gov (United States)

    Corigliano, Mariana G.; Maglioco, Andrea; Laguía Becher, Melina; Goldman, Alejandra; Martín, Valentina; Angel, Sergio O.; Clemente, Marina

    2011-01-01

    Background The molecular chaperone heat shock protein 90 (Hsp90) plays an important role in folding stabilization and activation of client proteins. Besides, Hsp90 of mammals and mammalian pathogens displays immunostimulatory properties. Here, we investigated the role of plant-derived Hsp90s as B-cell mitogens by measuring their proliferative responses in vitro. Methodology Plant cytosolic Hsp90 isoforms from Arabidopsis thaliana (AtHsp81.2) and Nicotiana benthamiana (NbHsp90.3) were expressed in E. coli. Over-expression of recombinant plant Hsp90s (rpHsp90s) was confirmed by SDS-PAGE and western blot using and anti-AtHsp81.2 polyclonal anti-body. Both recombinant proteins were purified by Ni-NTA affinity chromatography and their identity confirmed by MALDI-TOF-TOF. Recombinant AtHsp81.2 and NbHsp90.3 proteins induced prominent proliferative responses in spleen cells form BALB/c mice. Polymyxin-B, a potent inhibitor of lipopolysaccharide (LPS), did not eliminate the rpHsp90-induced proliferation. In addition, in vitro incubation of spleen cells with rpHsp90 led to the expansion of CD19-bearing populations, suggesting a direct effect of these proteins on B lymphocytes. This effect was confirmed by immunofluorescence analysis, where a direct binding of rpHsp90 to B- but not to T-cells was observed in cells from BALB/c and C3H/HeN mice. Finally, we examined the involvement of Toll Like Receptor 4 (TLR4) molecules in the rpHsp90s induction of B-cell proliferation. Spleen cells from C3H/HeJ mice, which carry a point mutation in the cytoplasmic region of TLR4, responded poorly to prAtHsp90. However, the interaction between rpHsp90 and B-cells from C3H/HeJ mice was not altered, suggesting that the mutation on TLR4 would be affecting the signal cascade but not the rpHsp90-TLR4 receptor interaction. Conclusions Our results show for the first time that spleen cell proliferation can be stimulated by a non-pathogen-derived Hsp90. Furthermore, our data provide a new example of

  9. B cell sub-types following acute malaria and associations with clinical immunity.

    Science.gov (United States)

    Sullivan, Richard T; Ssewanyana, Isaac; Wamala, Samuel; Nankya, Felistas; Jagannathan, Prasanna; Tappero, Jordan W; Mayanja-Kizza, Harriet; Muhindo, Mary K; Arinaitwe, Emmanuel; Kamya, Moses; Dorsey, Grant; Feeney, Margaret E; Riley, Eleanor M; Drakeley, Chris J; Greenhouse, Bryan; Sullivan, Richard

    2016-03-03

    Repeated exposure to Plasmodium falciparum is associated with perturbations in B cell sub-set homeostasis, including expansion atypical memory B cells. However, B cell perturbations immediately following acute malaria infection have been poorly characterized, especially with regard to their relationship with immunity to malaria. To better understand the kinetics of B cell sub-sets following malaria, the proportions of six B cell sub-sets were assessed at five time points following acute malaria in four to 5 years old children living in a high transmission region of Uganda. B cell sub-set kinetics were compared with measures of clinical immunity to malaria-lower parasite density at the time of malaria diagnosis and recent asymptomatic parasitaemia. Atypical memory B cell and transitional B cell proportions increased following malaria. In contrast, plasmablast proportions were highest at the time of malaria diagnosis and rapidly declined following treatment. Increased proportions of atypical memory B cells were associated with greater immunity to malaria, whereas increased proportions of transitional B cells were associated with evidence of less immunity to malaria. These findings highlight the dynamic changes in multiple B cell sub-sets following acute, uncomplicated malaria, and how these sub-sets are associated with developing immunity to malaria.

  10. A role for gut-associated lymphoid tissue in shaping the human B cell repertoire.

    Science.gov (United States)

    Vossenkämper, Anna; Blair, Paul A; Safinia, Niloufar; Fraser, Louise D; Das, Lisa; Sanders, Theodore J; Stagg, Andrew J; Sanderson, Jeremy D; Taylor, Kirstin; Chang, Fuju; Choong, Lee M; D'Cruz, David P; Macdonald, Thomas T; Lombardi, Giovanna; Spencer, Jo

    2013-08-26

    We have tracked the fate of immature human B cells at a critical stage in their development when the mature B cell repertoire is shaped. We show that a major subset of bone marrow emigrant immature human B cells, the transitional 2 (T2) B cells, homes to gut-associated lymphoid tissue (GALT) and that most T2 B cells isolated from human GALT are activated. Activation in GALT is a previously unknown potential fate for immature human B cells. The process of maturation from immature transitional B cell through to mature naive B cell includes the removal of autoreactive cells from the developing repertoire, a process which is known to fail in systemic lupus erythematosus (SLE). We observe that immature B cells in SLE are poorly equipped to access the gut and that gut immune compartments are depleted in SLE. Thus, activation of immature B cells in GALT may function as a checkpoint that protects against autoimmunity. In healthy individuals, this pathway may be involved in generating the vast population of IgA plasma cells and also the enigmatic marginal zone B cell subset that is poorly understood in humans.

  11. Identification of a B cell-dependent subpopulation of multiple sclerosis by measurements of brain-reactive B cells in the blood.

    Science.gov (United States)

    Kuerten, Stefanie; Pommerschein, Giovanna; Barth, Stefanie K; Hohmann, Christopher; Milles, Bianca; Sammer, Fabian W; Duffy, Cathrina E; Wunsch, Marie; Rovituso, Damiano M; Schroeter, Michael; Addicks, Klaus; Kaiser, Claudia C; Lehmann, Paul V

    2014-01-01

    B cells are increasingly coming into play in the pathogenesis of multiple sclerosis (MS). Here, we screened peripheral blood mononuclear cells (PBMC) from patients with clinically isolated syndrome (CIS), MS, other non-inflammatory neurological, inflammatory neurological or autoimmune diseases, and healthy donors for their B cell reactivity to CNS antigen using the enzyme-linked immunospot technique (ELISPOT) after 96 h of polyclonal stimulation. Our data show that nine of 15 patients with CIS (60.0%) and 53 of 67 patients with definite MS (79.1%) displayed CNS-reactive B cells, compared to none of the control donors. The presence of CNS-reactive B cells in the blood of the majority of patients with MS or at risk to develop MS along with their absence in control subjects suggests that they might be indicative of a B cell-dependent subpopulation of the disease. Copyright © 2014. Published by Elsevier Inc.

  12. B Cells Promote Th1- Skewed NKT Cell Response by CD1d-TCR Interaction.

    Science.gov (United States)

    Shin, Jung Hoon; Park, Se-Ho

    2013-10-01

    CD1d expressing dendritic cells (DCs) are good glyco-lipid antigen presenting cells for NKT cells. However, resting B cells are very weak stimulators for NKT cells. Although α-galactosylceramide (α-GalCer) loaded B cells can activate NKT cells, it is not well defined whether B cells interfere NKT cell stimulating activity of DCs. Unexpectedly, we found in this study that B cells can promote Th1-skewed NKT cell response, which means a increased level of IFN-γ by NKT cells, concomitant with a decreased level of IL-4, in the circumstance of co-culture of DCs and B Cells. Remarkably, the response promoted by B cells was dependent on CD1d expression of B cells.

  13. CEACAM1 induces B-cell survival and is essential for protective antiviral antibody production

    Science.gov (United States)

    Khairnar, Vishal; Duhan, Vikas; Maney, Sathish Kumar; Honke, Nadine; Shaabani, Namir; Pandyra, Aleksandra A.; Seifert, Marc; Pozdeev, Vitaly; Xu, Haifeng C.; Sharma, Piyush; Baldin, Fabian; Marquardsen, Florian; Merches, Katja; Lang, Elisabeth; Kirschning, Carsten; Westendorf, Astrid M.; Häussinger, Dieter; Lang, Florian; Dittmer, Ulf; Küppers, Ralf; Recher, Mike; Hardt, Cornelia; Scheffrahn, Inka; Beauchemin, Nicole; Göthert, Joachim R.; Singer, Bernhard B.; Lang, Philipp A.; Lang, Karl S.

    2015-01-01

    B cells are essential for antiviral immune defence because they produce neutralizing antibodies, present antigen and maintain the lymphoid architecture. Here we show that intrinsic signalling of CEACAM1 is essential for generating efficient B-cell responses. Although CEACAM1 exerts limited influence on the proliferation of B cells, expression of CEACAM1 induces survival of proliferating B cells via the BTK/Syk/NF-κB-axis. The absence of this signalling cascade in naive Ceacam1−/− mice limits the survival of B cells. During systemic infection with cytopathic vesicular stomatitis virus, Ceacam1−/− mice can barely induce neutralizing antibody responses and die early after infection. We find, therefore, that CEACAM1 is a crucial regulator of B-cell survival, influencing B-cell numbers and protective antiviral antibody responses. PMID:25692415

  14. Newly Identified TLR9 Stimulant, M6-395 Is a Potent Polyclonal Activator for Murine B Cells.

    Science.gov (United States)

    Park, Mi-Hee; Jung, Yu-Jin; Kim, Pyeung-Hyeun

    2012-02-01

    Toll-like receptors (TLRs) have been extensively studied in recent years. However, functions of these molecules in murine B cell biology are largely unknown. A TLR4 stimulant, LPS is well known as a powerful polyclonal activator for murine B cells. In this study, we explored the effect of a murine TLR9 stimulant, M6-395 (a synthetic CpG ODNs) on B cell proliferation and Ig production. First, M6-395 was much more potent than LPS in augmenting B cell proliferation. As for Ig expression, M6-395 facilitated the expression of both TGF-β1-induced germ line transcript α (GLTα) and IL-4-induced GLTγ1 as levels as those by LPS and Pam3CSK4 (TLR1/2 agonist) : a certain Ig GLT expression is regarded as an indicative of the corresponding isotype switching recombination. However, IgA and IgG1 secretion patterns were quite different--these Ig isotype secretions by M6-395 were much less than those by LPS and Pam3CSK4. Moreover, the increase of IgA and IgG1 production by LPS and Pam3CSK4 was virtually abrogated by M6-395. The same was true for the secretion of IgG3. We found that this unexpected phenomena provoked by M6-395 is attributed, at least in part, to its excessive mitogenic nature. Taken together, these results suggest that M6-395 can act as a murine polyclonal activator but its strong mitogenic activity is unfavorable to Ig isotype switching.

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

    Directory of Open Access Journals (Sweden)

    Mark T Winkler

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

  16. Generation mechanism of RANKL(+) effector memory B cells: relevance to the pathogenesis of rheumatoid arthritis.

    Science.gov (United States)

    Ota, Yuri; Niiro, Hiroaki; Ota, Shun-Ichiro; Ueki, Naoko; Tsuzuki, Hirofumi; Nakayama, Tsuyoshi; Mishima, Koji; Higashioka, Kazuhiko; Jabbarzadeh-Tabrizi, Siamak; Mitoma, Hiroki; Akahoshi, Mitsuteru; Arinobu, Yojiro; Kukita, Akiko; Yamada, Hisakata; Tsukamoto, Hiroshi; Akashi, Koichi

    2016-03-16

    The efficacy of B cell-depleting therapies for rheumatoid arthritis underscores antibody-independent functions of effector B cells such as cognate T-B interactions and production of pro-inflammatory cytokines. Receptor activator of nuclear factor κB ligand (RANKL) is a key cytokine involved in bone destruction and is highly expressed in synovial fluid B cells in patients with rheumatoid arthritis. In this study we sought to clarify the generation mechanism of RANKL(+) effector B cells and their impacts on osteoclast differentiation. Peripheral blood and synovial fluid B cells from healthy controls and patients with rheumatoid arthritis were isolated using cell sorter. mRNA expression of RANKL, osteoprotegerin, tumor necrosis factor (TNF)-α, and Blimp-1 was analyzed by quantitative real-time polymerase chain reaction. Levels of RANKL, CD80, CD86, and CXCR3 were analyzed using flow cytometry. Functional analysis of osteoclastogenesis was carried out in the co-culture system using macrophage RAW264 reporter cells. RANKL expression was accentuated in CD80(+)CD86(+) B cells, a highly activated B-cell subset more abundantly observed in patients with rheumatoid arthritis. Upon activation via B-cell receptor and CD40, switched-memory B cells predominantly expressed RANKL, which was further augmented by interferon-γ (IFN-γ) but suppressed by interleukin-21. Strikingly, IFN-γ also enhanced TNF-α expression, while it strongly suppressed osteoprotegerin expression in B cells. IFN-γ increased the generation of CXCR3(+)RANKL(+) effector B cells, mimicking the synovial B cell phenotype in patients with rheumatoid arthritis. Finally, RANKL(+) effector B cells in concert with TNF-α facilitated osteoclast differentiation in vitro. Our current findings have shed light on the generation mechanism of pathogenic RANKL(+) effector B cells that would be an ideal therapeutic target for rheumatoid arthritis in the future.

  17. B-Cell Dysregulation in Crohn's Disease Is Partially Restored with Infliximab Therapy.

    Directory of Open Access Journals (Sweden)

    Wilhelmina M C Timmermans

    Full Text Available B-cell depletion can improve a variety of chronic inflammatory diseases, but does not appear beneficial for patients with Crohn's disease.To elucidate the involvement of B cells in Crohn's disease, we here performed an 'in depth' analysis of intestinal and blood B-cells in this chronic inflammatory disease.Patients with Crohn's disease were recruited to study B-cell infiltrates in intestinal biopsies (n = 5, serum immunoglobulin levels and the phenotype and molecular characteristics of blood B-cell subsets (n = 21. The effects of infliximab treatment were studied in 9 patients.Granulomatous tissue showed infiltrates of B lymphocytes rather than Ig-secreting plasma cells. Circulating transitional B cells and CD21low B cells were elevated. IgM memory B cells were reduced and natural effector cells showed decreased replication histories and somatic hypermutation (SHM levels. In contrast, IgG and IgA memory B cells were normally present and their Ig gene transcripts carried increased SHM levels. The numbers of transitional and natural effector cells were normal in patients who responded clinically well to infliximab.B cells in patients with Crohn's disease showed signs of chronic stimulation with localization to granulomatous tissue and increased molecular maturation of IgA and IgG. Therapy with TNFα-blockers restored the defect in IgM memory B-cell generation and normalized transitional B-cell levels, making these subsets candidate markers for treatment monitoring. Together, these results suggest a chronic, aberrant B-cell response in patients with Crohn's disease, which could be targeted with new therapeutics that specifically regulate B-cell function.

  18. B cell follicle-like structures in multiple sclerosis-with focus on the role of B cell activating factor

    DEFF Research Database (Denmark)

    Morten, Haugen; Frederiksen, Jette L; Vinter, Matilda Degn

    2014-01-01

    B lymphocytes play an important role in the pathogenesis of multiple sclerosis (MS). Follicle-like structures (FLS) have recently been found in the subarachnoid space in the leptomeninges in some patients with secondary progressive MS (SPMS). They contain proliferating B lymphocytes, plasma cells......, helper T lymphocytes and a network of follicular dendritic cells. FLS have been shown to correlate with increased cortical demyelination, neuronal loss, meningeal infiltration and central nervous system inflammation, as well as lower age at disease onset and progression to severe disability and death....... In this review, we will discuss the role of FLS in MS pathogenesis and disease course and the possible influence by B cell activating factor (BAFF) and C-X-C motif chemokine 13 (CXCL13)....

  19. Plasma Cell Alloantigen 1 and IL-10 Secretion Define Two Distinct Peritoneal B1a B Cell Subsets With Opposite Functions, PC1high Cells Being Protective and PC1low Cells Harmful for the Growing Fetus

    Directory of Open Access Journals (Sweden)

    Anne Schumacher

    2018-05-01

    Full Text Available B cells possess various immuno regulatory functions. However, research about their participation in tolerance induction toward the fetus is just emerging. Accumulating evidence supports the idea that B cells can play seemingly conflicting roles during pregnancy, either protecting or harming the fetus. Previous findings indicated the presence of two different peritoneal B cell subsets, defined by the expression of the plasma cell alloantigen 1 (PC1 and with distinct immune modulatory functions. Here, we aimed to study the participation of these two B cell subsets, on pregnancy outcome in a murine model of disturbed fetal tolerance. The frequencies and cell numbers of peritoneal and splenic CD19+IL-10+ and CD19+CD5+IL-10+PC1+ cells were assessed in virgin as well as normal pregnant (NP and abortion-prone (AP females during the course of gestation. Peritoneal PC1low or PC1high B1a B cells were sorted, analyzed for their ability to secrete IL-10 and adoptively transferred into NP or AP females. On gestation day (gd 12, the abortion rate as well as the frequencies and cell numbers of regulatory T cells, TH1 and TH17 cells were determined in spleens and decidua. In addition, mRNA expression of IL-10, TGF-β, IFN-γ, and TNF-α was analyzed in decidual tissue. Peritoneal CD19+IL-10+ and CD19+CD5+IL-10+PC1+ frequencies fluctuated during the progression of normal pregnancies while no significant changes were observed in spleen. AP females showed significantly reduced frequencies of both B cell populations and exhibited an altered peritoneal PC1high/PC1low ratio at gd10. Adoptive transfers of PC1low B1a B cells into NP females increased the abortion rate in association with a reduced splenic regulatory T/TH17 ratio. By contrast, the transfer of PC1high B1a B cells into AP females significantly diminished the fetal rejection rate and significantly reduced the numbers of splenic TH17 cells. Our results suggest that the peritoneum harbors two distinct B1a B

  20. Spectratyping analysis of the islet-reactive T cell repertoire in diabetic NOD Igμnull mice after polyclonal B cell reconstitution

    Directory of Open Access Journals (Sweden)

    Sercarz Eli E

    2011-07-01

    Full Text Available Abstract Background Non Obese Diabetic mice lacking B cells (NOD.Igμnull mice do not develop diabetes despite their susceptible background. Upon reconstitution of B cells using a chimera approach, animals start developing diabetes at 20 weeks of age. Methods We have used the spectratyping technique to follow the T cell receptor (TCR V beta repertoire of NOD.Igμnull mice following B cell reconstitution. This technique provides an unbiased approach to understand the kinetics of TCR expansion. We have also analyzed the TCR repertoire of reconstituted animals receiving cyclophosphamide treatment and following tissue transplants to identify common aggressive clonotypes. Results We found that B cell reconstitution of NOD.Igμnull mice induces a polyclonal TCR repertoire in the pancreas 10 weeks later, gradually diversifying to encompass most BV families. Interestingly, these clonotypic BV expansions are mainly confined to the pancreas and are absent from pancreatic lymph nodes or spleens. Cyclophosphamide-induced diabetes at 10 weeks post-B cell reconstitution reorganized the predominant TCR repertoires by removing potential regulatory clonotypes (BV1, BV8 and BV11 and increasing the frequency of others (BV4, BV5S2, BV9, BV16-20. These same clonotypes are more frequently present in neonatal pancreatic transplants under the kidney capsule of B-cell reconstituted diabetic NOD.Igμnull mice, suggesting their higher invasiveness. Phenotypic analysis of the pancreas-infiltrating lymphocytes during diabetes onset in B cell reconstituted animals show a predominance of CD19+ B cells with a B:T lymphocyte ratio of 4:1. In contrast, in other lymphoid organs (pancreatic lymph nodes and spleens analyzed by FACS, the B:T ratio was 1:1. Lymphocytes infiltrating the pancreas secrete large amounts of IL-6 and are of Th1 phenotype after CD3-CD28 stimulation in vitro. Conclusions Diabetes in NOD.Igμnull mice appears to be caused by a polyclonal repertoire of T cell

  1. APECED: Is this a model for failure of T-cell and B-cell tolerance?

    Directory of Open Access Journals (Sweden)

    Nicolas eKluger

    2012-08-01

    Full Text Available APECED and IPEX syndromes show similarities in the clinical presentations and immunological alterations, mainly regarding regulatory T-cells function. T-cell defect may lead to tissue destruction chiefly in endocrine organs. Besides, APECED is characterized by high-titer antibodies against a wide variety of cytokines, that could partly be responsible for the clinical symptoms during APECED, mainly chronic mucocutaneous candidiasis, and linked to antibodies against Th17 cells effector molecules, IL-17 and IL-22. On the other hand, the same antibodies, together with antibodies against type I interferons may be prevent from other immunological diseases, such as psoriasis and systemic lupus erythematous. The same effector Th17 cells, present in the lymphocytic infiltrate of target organs of APECED, could be responsible for the tissue destruction. Here again, the antibodies against the corresponding effector molecules, anti-IL-17 and anti-IL-22 could be protective. The occurrence of several effector mechanisms (CD4+ Th17 cell and CD8+ CTL and the effector cytokines IL-17 and IL-22, and simultaneous existence of regulatory mechanisms (CD4+ and CD8+ Treg and antibodies neutralizing the effect of the effector cytokines may explain the polymorphism of APECED. Almost all the patients develop the characteristic manifestations of the complex, but temporal course and symptoms severity vary considerably, even among siblings. The autoantibody profile does not correlate with the clinical picture. One could speculate that a secondary homeostatic balance between the harmful effector mechanisms, and the favorable regulatory mechanisms, finally define both the extent and severity of the clinical condition in the AIRE defective individuals. The proposed hypothesis that in APECED, in addition to strong tissue destructive mechanisms, a controlling regulatory mechanism does exist, allow us to conclude that APECED could be treated, and even cured, with immunological

  2. Alterations on peripheral B cell subsets following an acute uncomplicated clinical malaria infection in children

    Directory of Open Access Journals (Sweden)

    Ng'ang'a Zipporah W

    2008-11-01

    Full Text Available Abstract Background The effects of Plasmodium falciparum on B-cell homeostasis have not been well characterized. This study investigated whether an episode of acute malaria in young children results in changes in the peripheral B cell phenotype. Methods Using flow-cytofluorimetric analysis, the B cell phenotypes found in the peripheral blood of children aged 2–5 years were characterized during an episode of acute uncomplicated clinical malaria and four weeks post-recovery and in healthy age-matched controls. Results There was a significant decrease in CD19+ B lymphocytes during acute malaria. Characterization of the CD19+ B cell subsets in the peripheral blood based on expression of IgD and CD38 revealed a significant decrease in the numbers of naive 1 CD38-IgD+ B cells while there was an increase in CD38+IgD- memory 3 B cells during acute malaria. Further analysis of the peripheral B cell phenotype also identified an expansion of transitional CD10+CD19+ B cells in children following an episode of acute malaria with up to 25% of total CD19+ B cell pool residing in this subset. Conclusion Children experiencing an episode of acute uncomplicated clinical malaria experienced profound disturbances in B cell homeostasis.

  3. SAP modulates B cell functions in a genetic background-dependent manner.

    Science.gov (United States)

    Detre, Cynthia; Yigit, Burcu; Keszei, Marton; Castro, Wilson; Magelky, Erica M; Terhorst, Cox

    2013-06-01

    Mutations affecting the SLAM-associated protein (SAP) are responsible for the X-linked lympho-proliferative syndrome (XLP), a severe primary immunodeficiency syndrome with disease manifestations that include fatal mononucleosis, B cell lymphoma and dysgammaglobulinemia. It is well accepted that insufficient help by SAP-/- CD4+ T cells, in particular during the germinal center reaction, is a component of dysgammaglobulinemia in XLP patients and SAP-/- animals. It is however not well understood whether in XLP patients and SAP-/- mice B cell functions are affected, even though B cells themselves do not express SAP. Here we report that B cell intrinsic responses to haptenated protein antigens are impaired in SAP-/- mice and in Rag-/- mice into which B cells derived from SAP-/- mice together with wt CD4+ T cells had been transferred. This impaired B cells functions are in part depending on the genetic background of the SAP-/- mouse, which affects B cell homeostasis. Surprisingly, stimulation with an agonistic anti-CD40 causes strong in vivo and in vitro B cell responses in SAP-/- mice. Taken together, the data demonstrate that genetic factors play an important role in the SAP-related B cell functions. The finding that anti-CD40 can in part restore impaired B cell responses in SAP-/- mice, suggests potentially novel therapeutic interventions in subsets of XLP patients. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. IL-4Rα-associated antigen processing by B cells promotes immunity in Nippostrongylus brasiliensis infection.

    Directory of Open Access Journals (Sweden)

    William G C Horsnell

    2013-10-01

    Full Text Available In this study, B cell function in protective T(H2 immunity against N. brasiliensis infection was investigated. Protection against secondary infection depended on IL-4Rα and IL-13; but not IL-4. Protection did not associate with parasite specific antibody responses. Re-infection of B cell-specific IL-4Rα⁻/⁻ mice resulted in increased worm burdens compared to control mice, despite their equivalent capacity to control primary infection. Impaired protection correlated with reduced lymphocyte IL-13 production and B cell MHC class II and CD86 surface expression. Adoptive transfer of in vivo N. brasiliensis primed IL-4Rα expressing B cells into naïve BALB/c mice, but not IL-4Rα or IL-13 deficient B cells, conferred protection against primary N. brasiliensis infection. This protection required MHC class II compatibility on B cells suggesting cognate interactions by B cells with CD4⁺ T cells were important to co-ordinate immunity. Furthermore, the rapid nature of these protective effects by B cells suggested non-BCR mediated mechanisms, such as via Toll Like Receptors, was involved, and this was supported by transfer experiments using antigen pulsed Myd88⁻/⁻ B cells. These data suggest TLR dependent antigen processing by IL-4Rα-responsive B cells producing IL-13 contribute significantly to CD4⁺ T cell-mediated protective immunity against N. brasiliensis infection.

  5. Selective induction of DNA repair pathways in human B cells activated by CD4+ T cells.

    Directory of Open Access Journals (Sweden)

    Xiaosheng Wu

    Full Text Available Greater than 75% of all hematologic malignancies derive from germinal center (GC or post-GC B cells, suggesting that the GC reaction predisposes B cells to tumorigenesis. Because GC B cells acquire expression of the highly mutagenic enzyme activation-induced cytidine deaminase (AID, GC B cells may require additional DNA repair capacity. The goal of this study was to investigate whether normal human B cells acquire enhanced expression of DNA repair factors upon AID induction. We first demonstrated that several DNA mismatch repair, homologous recombination, base excision repair, and ATR signaling genes were overexpressed in GC B cells relative to naïve and memory B cells, reflecting activation of a process we have termed somatic hyperrepair (SHR. Using an in vitro system, we next characterized activation signals required to induce AID expression and SHR. Although AID expression was induced by a variety of polyclonal activators, SHR induction strictly required signals provided by contact with activated CD4+ T cells, and B cells activated in this manner displayed reduced levels of DNA damage-induced apoptosis. We further show the induction of SHR is independent of AID expression, as GC B cells from AID-/-mice retained heightened expression of SHR proteins. In consideration of the critical role that CD4+ T cells play in inducing the SHR process, our data suggest a novel role for CD4+ T cells in the tumor suppression of GC/post-GC B cells.

  6. A two-scale model for correlation between B cell VDJ usage in zebrafish

    Science.gov (United States)

    Pan, Keyao; Deem, Michael

    2011-03-01

    The zebrafish (Danio rerio) is one of the model animals for study of immunology. The dynamics of the adaptive immune system in zebrafish is similar to that in higher animals. In this work, we built a two-scale model to simulate the dynamics of B cells in primary and secondary immune reactions in zebrafish and to explain the reported correlation between VDJ usage of B cell repertoires in distinct zebrafish. The first scale of the model consists of a generalized NK model to simulate the B cell maturation process in the 10-day primary immune response. The second scale uses a delay ordinary differential equation system to model the immune responses in the 6-month lifespan of zebrafish. The generalized NK model shows that mature B cells specific to one antigen mostly possess a single VDJ recombination. The probability that mature B cells in two zebrafish have the same VDJ recombination increases with the B cell population size or the B cell selection intensity and decreases with the B cell hypermutation rate. The ODE model shows a distribution of correlation in the VDJ usage of the B cell repertoires in two six-month-old zebrafish that is highly similar to that from experiment. This work presents a simple theory to explain the experimentally observed correlation in VDJ usage of distinct zebrafish B cell repertoires after an immune response.

  7. Induction of polyclonal B cell activation and differentiation by the AIDS retrovirus (HTLV-III/LAV)

    International Nuclear Information System (INIS)

    Higgins, S.E.; Schnittman, S.M.; Lane, H.C.; Folks, T.; Koenig, S.; Fauci, A.S.

    1986-01-01

    The immune systems of individuals infected with HTLV-III/LAV are characterized by a profound defect in cellular immunity together with paradoxical polyclonal B cell activation. The present study examined the direct effects of HTLV-III/LAV on B lymphocytes. Peripheral blood B cells from healthy donors were incubated with a variety of HTLV-III/LAV isolates for 1 h and 3 H-thymidine incorporation was measured at multiple time points. Responses ranged from 9000-28,000 cpm and peaked on day 4. This B cell activation was not enhanced by the addition of interleukin-2 to culture, was not synergistic with Staphylococcus aureus Cowan I, was not modulated by the addition of T lymphocytes to culture, and was not associated with B cell transformation. Supernatant Ig could first be detected in virus-activated cultures at day 4, plateaued by day 8, and yielded a mean of 12,500 ng IgG+IgM/ml/50,000 B cells. Thus, HTLV-III/LAV is a potent T cell independent B cell mitogen capable of inducing B cell activation, proliferation, and differentiation comparable in magnitude to that of the most potent B cell activators. This biological property of HTLV-III/LAV may help explain the profound polyclonal B cell activation observed in patients with AIDS and may provide investigators with another probe for investigating the mechanisms of B cell activation

  8. Molecule Matters

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 4. Molecule Matters – van der Waals Molecules - History and Some Perspectives on Intermolecular Forces. E Arunan. Feature Article Volume 14 Issue 4 April 2009 pp 346-356 ...

  9. CD19 CAR-targeted T cells induce long-term remission and B Cell Aplasia in an immunocompetent mouse model of B cell acute lymphoblastic leukemia.

    Directory of Open Access Journals (Sweden)

    Marco L Davila

    Full Text Available Although many adults with B cell acute lymphoblastic leukemia (B-ALL are induced into remission, most will relapse, underscoring the dire need for novel therapies for this disease. We developed murine CD19-specific chimeric antigen receptors (CARs and an immunocompetent mouse model of B-ALL that recapitulates the disease at genetic, cellular, and pathologic levels. Mouse T cells transduced with an all-murine CD3ζ/CD28-based CAR that is equivalent to the one being used in our clinical trials, eradicate B-ALL in mice and mediate long-term B cell aplasias. In this model, we find that increasing conditioning chemotherapy increases tumor eradication, B cell aplasia, and CAR-modified T cell persistence. Quantification of recipient B lineage cells allowed us to estimate an in vivo effector to endogenous target ratio for B cell aplasia maintenance. In mice exhibiting a dramatic B cell reduction we identified a small population of progenitor B cells in the bone marrow that may serve as a reservoir for long-term CAR-modified T cell stimulation. Lastly, we determine that infusion of CD8+ CAR-modified T cells alone is sufficient to maintain long-term B cell eradication. The mouse model we report here should prove valuable for investigating CAR-based and other therapies for adult B-ALL.

  10. Splenectomy associated changes in IgM memory B cells in an adult spleen registry cohort.

    Directory of Open Access Journals (Sweden)

    Paul U Cameron

    Full Text Available Asplenic patients have a lifelong risk of overwhelming post-splenectomy infection and have been reported to have low numbers of peripheral blood IgM memory B cells. The clinical value of quantitation of memory B cells as an indicator of splenic abnormality or risk of infection has been unclear. To assess changes in B cell sub-populations after splenectomy we studied patients recruited to a spleen registry (n = 591. A subset of 209 adult asplenic or hyposplenic subjects, and normal controls (n = 140 were tested for IgM memory B cells. We also determined a changes in IgM memory B cells with time after splenectomy using the cross-sectional data from patients on the registry and b the kinetics of changes in haematological markers associated with splenectomy(n = 45. Total B cells in splenectomy patients did not differ from controls, but memory B cells, IgM memory B cells and switched B cells were significantly (p<0.001 reduced. The reduction was similar for different indications for splenectomy. Changes of asplenia in routine blood films including presence of Howell-Jolly bodies (HJB, occurred early (median 25 days and splenectomy associated thrombocytosis and lymphocytosis peaked by 50 days. There was a more gradual decrease in IgM memory B cells reaching a stable level within 6 months after splenectomy. IgM memory B cells as proportion of B cells was the best discriminator between splenectomized patients and normal controls and at the optimal cut-off of 4.53, showed a true positive rate of 95% and false positive rate of 20%. In a survey of 152 registry patients stratified by IgM memory B cells around this cut-off there was no association with minor infections and no registry patients experienced OPSI during the study. Despite significant changes after splenectomy, conventional measures of IgM memory cells have limited clinical utility in this population.

  11. Prevalence of polyreactive innate clones among graft--infiltrating B cells in human cardiac allograft vasculopathy.

    Science.gov (United States)

    Chatterjee, Debanjana; Moore, Carolina; Gao, Baoshan; Clerkin, Kevin J; See, Sarah B; Shaked, David; Rogers, Kortney; Nunez, Sarah; Veras, Yokarla; Addonizio, Linda; Givertz, Michael M; Naka, Yoshifumi; Mancini, Donna; Vasilescu, Rodica; Marboe, Charles; Restaino, Susan; Madsen, Joren C; Zorn, Emmanuel

    2018-03-01

    Cardiac allograft vasculopathy (CAV) has been associated with graft-infiltrating B cells, although their characteristics are still unclear. In this study we examined the frequency, localization and reactivity profile of graft-infiltrating B cells to determine their contribution to the pathophysiology of CAV. B cells, plasma cells and macrophages were examined by immunohistochemistry in 56 allografts with CAV, 49 native failed hearts and 25 autopsy specimens. A total of 102 B-cell clones were immortalized directly from the infiltrates of 3 fresh cardiac samples with CAV. Their secreted antibodies were assessed using enzyme-linked immunoassay and flow cytometry. B-cell infiltration was observed around coronary arteries in 93% of allograft explants with CAV. Comparatively, intragraft B cells were less frequent and less dense in the intraventricular myocardium from where routine biopsies are obtained. Plasma cells and macrophages were also detected in 85% and 95% of explants, respectively. Remarkably, B-cell infiltrates were not associated with circulating donor-specific antibodies (DSA) or prior episodes of antibody-mediated rejection (AMR). Among all B-cell clones generated from 3 explants with CAV, a majority secreted natural antibodies reactive to multiple autoantigens and apoptotic cells, a characteristic of innate B cells. Our study reveals a high frequency of infiltrating B cells around the coronary arteries of allografts with CAV, independent of DSA or AMR. These cells are enriched for innate B cells with a polyreactive profile. The findings shift the focus from conventional DSA-producing B cells to the potentially pathogenic polyreactive B cells in the development of clinical CAV. Copyright © 2018 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  12. Splenectomy Associated Changes in IgM Memory B Cells in an Adult Spleen Registry Cohort

    Science.gov (United States)

    Cameron, Paul U.; Jones, Penelope; Gorniak, Malgorzata; Dunster, Kate; Paul, Eldho; Lewin, Sharon; Woolley, Ian; Spelman, Denis

    2011-01-01

    Asplenic patients have a lifelong risk of overwhelming post-splenectomy infection and have been reported to have low numbers of peripheral blood IgM memory B cells. The clinical value of quantitation of memory B cells as an indicator of splenic abnormality or risk of infection has been unclear. To assess changes in B cell sub-populations after splenectomy we studied patients recruited to a spleen registry (n = 591). A subset of 209 adult asplenic or hyposplenic subjects, and normal controls (n = 140) were tested for IgM memory B cells. We also determined a) changes in IgM memory B cells with time after splenectomy using the cross-sectional data from patients on the registry and b) the kinetics of changes in haematological markers associated with splenectomy(n = 45). Total B cells in splenectomy patients did not differ from controls, but memory B cells, IgM memory B cells and switched B cells were significantly (psplenectomy. Changes of asplenia in routine blood films including presence of Howell-Jolly bodies (HJB), occurred early (median 25 days) and splenectomy associated thrombocytosis and lymphocytosis peaked by 50 days. There was a more gradual decrease in IgM memory B cells reaching a stable level within 6 months after splenectomy. IgM memory B cells as proportion of B cells was the best discriminator between splenectomized patients and normal controls and at the optimal cut-off of 4.53, showed a true positive rate of 95% and false positive rate of 20%. In a survey of 152 registry patients stratified by IgM memory B cells around this cut-off there was no association with minor infections and no registry patients experienced OPSI during the study. Despite significant changes after splenectomy, conventional measures of IgM memory cells have limited clinical utility in this population. PMID:21829713

  13. Translocation of the B cell receptor to lipid rafts is inhibited in B cells from BLV-infected, persistent lymphocytosis cattle

    International Nuclear Information System (INIS)

    Hamilton, Valerie T.; Stone, Diana M.; Cantor, Glenn H.

    2003-01-01

    Bovine leukemia virus (BLV) infection causes a significant polyclonal expansion of CD5 + , IgM+ B lymphocytes known as persistent lymphocytosis (PL) in approximately 30% of infected cattle. There is evidence that this expanded B cell population has altered signaling, and resistance to apoptosis has been proposed as one mechanism of B cell expansion. In human and murine B cells, antigen binding initiates movement of the B cell receptor (BCR) into membrane microdomains enriched in sphingolipids and cholesterol, termed lipid rafts. Lipid rafts include members of the Src-family kinases and exclude certain phosphatases. Inclusion of the BCR into lipid rafts plays an important role in regulation of early signaling events and subsequent antigen internalization. Viral proteins may also influence signaling events in lipid rafts. Here we demonstrate that the largely CD5 + B cell population in PL cattle has different mobilization and internalization of the BCR when compared to the largely CD5-negative B cells in BLV-negative cattle. Unlike B cells from BLV-negative cattle, the BCR in B cells of BLV-infected, PL cattle resists movement into lipid rafts upon stimulation and is only weakly internalized. Expression of viral proteins as determined by detection of the BLV transmembrane (TM) envelope glycoprotein gp30 did not alter these events in cells from PL cattle. This exclusion of the BCR from lipid rafts may, in part, explain signaling differences seen between B cells of BLV-infected, PL, and BLV-negative cattle and the resistance to apoptosis speculated to contribute to persistent lymphocytosis

  14. Evaluation of CD307a expression patterns during normal B-cell maturation and in B-cell malignancies by flow cytometry.

    Science.gov (United States)

    Auat, Mariangeles; Cardoso, Chandra Chiappin; Santos-Pirath, Iris Mattos; Rudolf-Oliveira, Renata Cristina Messores; Matiollo, Camila; Lange, Bárbara Gil; da Silva, Jessica Pires; Dametto, Gisele Cristina; Pirolli, Mayara Marin; Colombo, Maria Daniela Holthausen Perico; Santos-Silva, Maria Claudia

    2018-02-24

    Flow cytometric immunophenotyping is deemed a fundamental tool for the diagnosis of B-cell neoplasms. Currently, the investigation of novel immunophenotypic markers has gained importance, as they can assist in the precise subclassification of B-cell malignancies by flow cytometry. Therefore, the purpose of the present study was to evaluate the expression of CD307a during normal B-cell maturation and in B-cell malignancies as well as to investigate its potential role in the differential diagnosis of these entities. CD307a expression was assessed by flow cytometry in normal precursor and mature B cells and in 115 samples collected from patients diagnosed with precursor and mature B-cell neoplasms. CD307a expression was compared between neoplastic and normal B cells. B-acute lymphoblastic leukemia cases exhibited minimal expression of CD307a, displaying a similar expression pattern to that of normal B-cell precursors. Mantle cell lymphoma (MCL) cases showed the lowest levels of CD307a among mature B-cell neoplasms. CD307a expression was statistically lower in MCL cases than in chronic B lymphocytic leukemia (CLL) and marginal zone lymphoma (MZL) cases. No statistical differences were observed between CD307a expression in neoplastic and normal plasma cells. These results indicate that the assessment of CD307a expression by flow cytometry could be helpful to distinguish CLL from MCL, and the latter from MZL. Although these results are not entirely conclusive, they provide a basis for further studies in a larger cohort of patients. © 2018 International Clinical Cytometry Society. © 2018 International Clinical Cytometry Society.

  15. Physiology of B cells in mice with X-linked immunodeficiency (xid). III. Disappearance of xid B cells in double bone marrow chimeras

    International Nuclear Information System (INIS)

    Sprent, J.; Bruce, J.

    1984-01-01

    Evidence is presented that B cells from mice with X-linked immunodeficiency (xid) differentiate at a slower rate than normal B cells. This conclusion stems from studies in which (B6 X CBA/J)F1 mice were heavily irradiated (1,000 rads) and reconstituted with a mixture of T-depleted marrow cells taken from (a) nondefective B6 mice (H-2b) and (b) xid CBA/N or nondefective CBA/Ca mice (both H-2k). With transfer of CBA/Ca plus B6 marrow cells, the irradiated recipients become repopulated with B cells derived from both parental marrow sources; except for an early imbalance (probably reflecting Hh resistance), the degree of chimerism remained relatively stable over a period of more than 6 months. Very different results occurred with transfer of a mixture of xid CBA/N and normal B6 marrow. Within the first 2 months after marrow reconstitution, a low but significant proportion of the B cells in both spleen and lymph nodes were of CBA/N origin. Thereafter the proportion of these cells fell progressively, and by 6-9 months virtually all of the B cells were of B6 origin. This gradual decline in CBA/N-derived cells did not apply to other cell types, i.e., T cells or pluripotential stem cells. Analogous results were obtained with transfer of CBA/N vs. CBA/Ca marrow cells into sublethally irradiated (750 rads) (CBA/N X DBA/2)F1 male vs. female mice. For example, CBA/N-marrow derived B cells differentiated effectively and survived for long periods in F1 male mice (xid----xid) but not in F1 female mice (xid----normal). The finding that xid B cells eventually disappear in the presence of normal B cells strengthens the view that xid B cells are an abnormal population not represented in normal mice

  16. Multifocal Extranodal Involvement of Diffuse Large B-Cell Lymphoma

    Directory of Open Access Journals (Sweden)

    Devrim Cabuk

    2013-01-01

    Full Text Available Endobronchial involvement of extrapulmonary malignant tumors is uncommon and mostly associated with breast, kidney, colon, and rectum carcinomas. A 68-year-old male with a prior diagnosis of colon non-Hodgkin lymphoma (NHL was admitted to the hospital with a complaint of cough, sputum, and dyspnea. The chest radiograph showed right hilar enlargement and opacity at the right middle zone suggestive of a mass lesion. Computed tomography of thorax revealed a right-sided mass lesion extending to thoracic wall with the destruction of the third and the fourth ribs and a right hilar mass lesion. Fiberoptic bronchoscopy was performed in order to evaluate endobronchial involvement and showed stenosis with mucosal tumor infiltration in right upper lobe bronchus. The pathological examination of bronchoscopic biopsy specimen reported diffuse large B-cell lymphoma and the patient was accepted as the endobronchial recurrence of sigmoid colon NHL. The patient is still under treatment of R-ICE (rituximab-ifosfamide-carboplatin-etoposide chemotherapy and partial regression of pulmonary lesions was noted after 3 courses of treatment.

  17. Prognostic Assessment in Patients with Indolent B-Cell Lymphomas

    Directory of Open Access Journals (Sweden)

    Luca Arcaini

    2012-01-01

    Full Text Available Follicular lymphoma (FL is an indolent lymphoma with long median survival. Many studies have been performed to build up prognostic scores potentially useful to identify patients with poorer outcome. In 2004, an international consortium coordinated by the International Follicular Lymphoma Prognostic Factor project was established and a new prognostic study was launched (FLIPI2 using progression-free survival (PFS as main endpoint and integrating all the modern parameters prospectively collected. Low-grade non-Hodgkin lymphomas were once considered as a heterogenous group of lymphomas characterized by an indolent clinical course. Each entity is characterized by unique clinicobiologic features. Some studies have been focused on prognostic factors in single lymphoma subtypes, with the development of specific-entity scores based on retrospective series, for instance splenic marginal zone lymphoma (SMZL. A widely accepted prognostic tool for clinical usage for indolent non-follicular B-cell lymphomas is largely awaited. In this paper we summarized the current evidence regarding prognostic assessment of indolent follicular and non-follicular lymphomas.

  18. B Cell Intrinsic Mechanisms Constraining IgE Memory

    Directory of Open Access Journals (Sweden)

    Brice Laffleur

    2017-11-01

    Full Text Available Memory B cells and long-lived plasma cells are key elements of adaptive humoral immunity. Regardless of the immunoglobulin class produced, these cells can ensure long-lasting protection but also long-lasting immunopathology, thus requiring tight regulation of their generation and survival. Among all antibody classes, this is especially true for IgE, which stands as the most potent, and can trigger dramatic inflammatory reactions even when present in minute amounts. IgE responses and memory crucially protect against parasites and toxic components of venoms, conferring selective advantages and explaining their conservation in all mammalian species despite a parallel broad spectrum of IgE-mediated immunopathology. Long-term memory of sensitization and anaphylactic responses to allergens constitute the dark side of IgE responses, which can trigger multiple acute or chronic pathologic manifestations, some punctuated with life-threatening events. This Janus face of the IgE response and memory, both necessary and potentially dangerous, thus obviously deserves the most elaborated self-control schemes.

  19. Epigenetic Heterogeneity of B-Cell Lymphoma: Chromatin Modifiers

    Science.gov (United States)

    Hopp, Lydia; Nersisyan, Lilit; Löffler-Wirth, Henry; Arakelyan, Arsen; Binder, Hans

    2015-01-01

    We systematically studied the expression of more than fifty histone and DNA (de)methylating enzymes in lymphoma and healthy controls. As a main result, we found that the expression levels of nearly all enzymes become markedly disturbed in lymphoma, suggesting deregulation of large parts of the epigenetic machinery. We discuss the effect of DNA promoter methylation and of transcriptional activity in the context of mutated epigenetic modifiers such as EZH2 and MLL2. As another mechanism, we studied the coupling between the energy metabolism and epigenetics via metabolites that act as cofactors of JmjC-type demethylases. Our study results suggest that Burkitt’s lymphoma and diffuse large B-cell Lymphoma differ by an imbalance of repressive and poised promoters, which is governed predominantly by the activity of methyltransferases and the underrepresentation of demethylases in this regulation. The data further suggest that coupling of epigenetics with the energy metabolism can also be an important factor in lymphomagenesis in the absence of direct mutations of genes in metabolic pathways. Understanding of epigenetic deregulation in lymphoma and possibly in cancers in general must go beyond simple schemes using only a few modes of regulation. PMID:26506391

  20. Epigenetic Heterogeneity of B-Cell Lymphoma: Chromatin Modifiers

    Directory of Open Access Journals (Sweden)

    Lydia Hopp

    2015-10-01

    Full Text Available We systematically studied the expression of more than fifty histone and DNA (demethylating enzymes in lymphoma and healthy controls. As a main result, we found that the expression levels of nearly all enzymes become markedly disturbed in lymphoma, suggesting deregulation of large parts of the epigenetic machinery. We discuss the effect of DNA promoter methylation and of transcriptional activity in the context of mutated epigenetic modifiers such as EZH2 and MLL2. As another mechanism, we studied the coupling between the energy metabolism and epigenetics via metabolites that act as cofactors of JmjC-type demethylases. Our study results suggest that Burkitt’s lymphoma and diffuse large B-cell Lymphoma differ by an imbalance of repressive and poised promoters, which is governed predominantly by the activity of methyltransferases and the underrepresentation of demethylases in this regulation. The data further suggest that coupling of epigenetics with the energy metabolism can also be an important factor in lymphomagenesis in the absence of direct mutations of genes in metabolic pathways. Understanding of epigenetic deregulation in lymphoma and possibly in cancers in general must go beyond simple schemes using only a few modes of regulation.

  1. Antibody and B cell responses to Plasmodium sporozoites

    Directory of Open Access Journals (Sweden)

    Johanna N Dups

    2014-11-01

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

  2. Overexpression of a transcription factor LYL1 induces T- and B-cell lymphoma in mice.

    Science.gov (United States)

    Zhong, Y; Jiang, L; Hiai, H; Toyokuni, S; Yamada, Y

    2007-10-18

    LYL1, a member of the class II basic helix-loop-helix transcription factors, is aberrantly expressed in a fraction of human T-cell acute lymphoblastic leukemia. Here, we generated transgenic mice ubiquitously overexpressing LYL1 using a construct expressing full-length cDNA driven by a human elongation factor 1alpha promoter. Four independent lines exhibiting high LYL1 expression were established. Of these transgenic mice, 96% displayed loss of hair with a short kinked tail. Furthermore, 30% of them developed malignant lymphoma, with an average latent period of 352 days. In these mice, histological examination revealed tumor cell infiltration in multiple organs and immunohistochemical analysis showed that the infiltrated tumor cells were either CD3 or CD45R/B220-positive; fluorescence-activated cell sorter analysis indicated that each tumor consisted either of mainly CD4, CD8 double-positive T cells or mature B cells; the clonality of LYL1-induced lymphoma was confirmed by T-cell receptor rearrangement and immunoglobulin heavy-chain gene rearrangement analyses. Mammalian two-hybrid analysis and luciferase assay suggested that excess LYL1 blocked the dimerization of E2A and thus inhibited the regulatory activity of E2A on the CD4 promoter. Reverse transcription-polymerase chain reaction results showed that the expression of certain E2A/HEB target genes was downregulated. Taken together, our results provide direct evidence that aberrant expression of LYL1 plays a role in lymphomagenesis.

  3. Chronic Exposure to Malaria Is Associated with Inhibitory and Activation Markers on Atypical Memory B Cells and Marginal Zone-Like B Cells

    Directory of Open Access Journals (Sweden)

    Itziar Ubillos

    2017-08-01

    Full Text Available In persistent infections that are accompanied by chronic immune activation, such as human immunodeficiency virus, hepatitis C virus, and malaria, there is an increased frequency of a phenotypically distinct subset of memory B cells lacking the classic memory marker CD27 and showing a reduced capacity to produce antibodies. However, critical knowledge gaps remain on specific B cell changes and immune adaptation in chronic infections. We hypothesized that expansion of atypical memory B cells (aMBCs and reduction of activated peripheral marginal zone (MZ-like B cells in constantly exposed individuals might be accompanied by phenotypic changes that would confer a tolerogenic profile, helping to establish tolerance to infections. To better understand malaria-associated phenotypic abnormalities on B cells, we analyzed peripheral blood mononuclear cells from 55 pregnant women living in a malaria-endemic area of Papua Nueva Guinea and 9 Spanish malaria-naïve individuals using four 11-color flow cytometry panels. We assessed the expression of markers of B cell specificity (IgG and IgM, activation (CD40, CD80, CD86, b220, TACI, and CD150, inhibition (PD1, CD95, and CD71, and migration (CCR3, CXCR3, and CD62l. We found higher frequencies of active and resting aMBC and marked reduction of MZ-like B cells, although changes in absolute cell counts could not be assessed. Highly exposed women had higher PD1+-, CD95+-, CD40+-, CD71+-, and CD80+-activated aMBC frequencies than non-exposed subjects. Malaria exposure increased frequencies of b220 and proapoptotic markers PD1 and CD95, and decreased expression of the activation marker TACI on MZ-like B cells. The increased frequencies of inhibitory and apoptotic markers on activated aMBCs and MZ-like B cells in malaria-exposed adults suggest an immune-homeostatic mechanism for maintaining B cell development and function while simultaneously downregulating hyperreactive B cells. This mechanism would keep the B cell

  4. Changes in B Cell Populations and Merozoite Surface Protein-1-Specific Memory B Cell Responses after Prolonged Absence of Detectable P. falciparum Infection.

    Directory of Open Access Journals (Sweden)

    Cyrus Ayieko

    Full Text Available Clinical immunity to malaria declines in the absence of repeated parasite exposure. However, little is known about how B cell populations and antigen-specific memory B cells change in the absence of P. falciparum infection. A successful indoor residual insecticide spraying campaign in a highland area of western Kenya, led to an absence of blood-stage P. falciparum infection between March 2007 and April 2008. We assessed memory B cell responses in 45 adults at the beginning (April 2008 and end (April 2009 of a subsequent 12-month period during which none of the adults had evidence of asymptomatic parasitemia or clinical disease. Antibodies and memory B cells to the 42-kDa portion of the merozoite surface protein-1 (MSP-142 were measured using ELISA and ELISPOT assays, respectively. B cell populations were characterized by flow cytometry. From 2008 to 2009, the prevalence of MSP-142-specific memory B cells (45% vs. 55%, respectively, P = 0.32 or antibodies (91% vs. 82%, respectively, P = 0.32 did not differ significantly, although specific individuals did change from positive to negative and vice versa, particularly for memory B cells, suggesting possible low-level undetected parasitemia may have occurred in some individuals. The magnitude of MSP-142-specific memory B cells and levels of antibodies to MSP-142 also did not differ from 2008 to 2009 (P>0.10 for both. However, from 2008 to 2009 the proportions of both class-switched atypical (CD19+IgD-CD27-CD21-IgM- and class-switched activated (CD19+IgD-CD27+CD21-IgM- memory B cells decreased (both P<0.001. In contrast, class-switched resting classical memory B cells (CD19+IgD-CD27+CD21+IgM- increased (P<0.001. In this area of seasonal malaria transmission, a one- year absence of detectable P. falciparum infection was not associated with changes in the prevalence or level of MSP-142 specific memory B cells, but was associated with major changes in overall memory B cell subsets.

  5. Regulatory agencies and regulatory risk

    OpenAIRE

    Knieps, Günter; Weiß, Hans-Jörg

    2008-01-01

    The aim of this paper is to show that regulatory risk is due to the discretionary behaviour of regulatory agencies, caused by a too extensive regulatory mandate provided by the legislator. The normative point of reference and a behavioural model of regulatory agencies based on the positive theory of regulation are presented. Regulatory risk with regard to the future behaviour of regulatory agencies is modelled as the consequence of the ex ante uncertainty about the relative influence of inter...

  6. Semiallogenic fusions of MSI+ tumor cells and activated B cells induce MSI-specific T cell responses

    International Nuclear Information System (INIS)

    Garbe, Yvette; Klier, Ulrike; Linnebacher, Michael

    2011-01-01

    Various strategies have been developed to transfer tumor-specific antigens into antigen presenting cells in order to induce cytotoxic T cell responses against tumor cells. One approach uses cellular vaccines based on fusions of autologous antigen presenting cells and allogeneic tumor cells. The fusion cells combine antigenicity of the tumor cell with optimal immunostimulatory capacity of the antigen presenting cells. Microsatellite instability caused by mutational inactivation of DNA mismatch repair genes results in translational frameshifts when affecting coding regions. It has been shown by us and others that these mutant proteins lead to the presentation of immunogenic frameshift peptides that are - in principle - recognized by a multiplicity of effector T cells. We chose microsatellite instability-induced frameshift antigens as ideal to test for induction of tumor specific T cell responses by semiallogenic fusions of microsatellite instable carcinoma cells with CD40-activated B cells. Two fusion clones of HCT116 with activated B cells were selected for stimulation of T cells autologous to the B cell fusion partner. Outgrowing T cells were phenotyped and tested in functional assays. The fusion clones expressed frameshift antigens as well as high amounts of MHC and costimulatory molecules. Autologous T cells stimulated with these fusions were predominantly CD4 + , activated, and reacted specifically against the fusion clones and also against the tumor cell fusion partner. Interestingly, a response toward 6 frameshift-derived peptides (of 14 tested) could be observed. Cellular fusions of MSI + carcinoma cells and activated B cells combine the antigen-presenting capacity of the B cell with the antigenic repertoire of the carcinoma cell. They present frameshift-derived peptides and can induce specific and fully functional T cells recognizing not only fusion cells but also the carcinoma cells. These hybrid cells may have great potential for cellular immunotherapy and

  7. Recombinant human interleukin 2 acts as a B cell growth and differentiation promoting factor

    OpenAIRE

    Emmrich, F.; Moll, Heidrun; Simon, Markus M.

    2009-01-01

    Human B cells appropriately activated by a B cell mitogen are rendered susceptible to human Interleukin 2 (IL-2) as demonstrated with recombinant human IL-2 (rec. h IL-2). They show increased proliferation and drastically enhanced immunoglobulin secretion. Susceptibility to IL-2 is accompanied with the expression of the IL-2 receptor (Tac antigen) on B cells. The data suggest that IL-2 is one of the lymphokines directly involved in the activation of B lymphocytes.

  8. Aborted germinal center reactions and B cell memory by follicular T cells specific for a B cell receptor V region peptide.

    Science.gov (United States)

    Heiser, Ryan A; Snyder, Christopher M; St Clair, James; Wysocki, Lawrence J

    2011-07-01

    A fundamental problem in immunoregulation is how CD4(+) T cells react to immunogenic peptides derived from the V region of the BCR that are created by somatic mechanisms, presented in MHC II, and amplified to abundance by B cell clonal expansion during immunity. BCR neo Ags open a potentially dangerous avenue of T cell help in violation of the principle of linked Ag recognition. To analyze this issue, we developed a murine adoptive transfer model using paired donor B cells and CD4 T cells specific for a BCR-derived peptide. BCR peptide-specific T cells aborted ongoing germinal center reactions and impeded the secondary immune response. Instead, they induced the B cells to differentiate into short-lived extrafollicular plasmablasts that secreted modest quantities of Ig. These results uncover an immunoregulatory process that restricts the memory pathway to B cells that communicate with CD4 T cells via exogenous foreign Ag.

  9. EBI2 overexpression in mice leads to B1 B cell expansion and chronic lymphocytic leukemia-(CLL)-like B cell malignancies

    DEFF Research Database (Denmark)

    Niss Arfelt, Kristine; Barington, Line; Benned-Jensen, Tau

    2017-01-01

    -targeted expression of human EBI2 in mice reduces germinal center-dependent immune responses, reduces total IgM and IgG levels, and leads to increased proliferation and upregulation of cellular oncogenes. Furthermore, hEBI2 overexpression leads to an abnormally expanded CD5+ B1a B cell subset present as early as 4......Human and mouse chronic lymphocytic leukemia (CLL) develop from CD5+ B cells that in mice and macaques are known to define the distinct B1a B cell lineage. B1a cells are characterized by lack of germinal center development and the B1a cell population is increased in mice with reduced germinal...... cells towards the extrafollicular area, whereas downregulation is essential for germinal center formation. We therefore speculated whether increased expression of EBI2 would lead to an expanded B1 cell subset and, ultimately, progression to chronic lymphocytic leukemia. Here we demonstrate that B cell...

  10. One Patient, Two Uncommon B-Cell Neoplasms: Solitary Plasmacytoma following Complete Remission from Intravascular Large B-Cell Lymphoma Involving Central Nervous System

    Directory of Open Access Journals (Sweden)

    Joycelyn Lee

    2014-01-01

    Full Text Available Second lymphoid neoplasms are an uncommon but recognized feature of non-Hodgkin’s lymphomas, putatively arising secondary to common genetic or environmental risk factors. Previous limited evaluations of clonal relatedness between successive mature B-cell malignancies have yielded mixed results. We describe the case of a man with intravascular large B-cell lymphoma involving the central nervous system who went into clinical remission following immunochemotherapy and brain radiation, only to relapse 2 years later with a plasmacytoma of bone causing cauda equina syndrome. The plasmacytoma stained strongly for the cell cycle regulator cyclin D1 on immunohistochemistry, while the original intravascular large cell lymphoma was negative, a disparity providing no support for clonal identity between the 2 neoplasms. Continued efforts atcataloging and evaluating unique associations of B-cell malignancies are critical to improving understanding of overarching disease biology in B-cell malignancies.

  11. B Cells Promote Th1- Skewed NKT Cell Response by CD1d-TCR Interaction

    OpenAIRE

    Shin, Jung Hoon; Park, Se-Ho

    2013-01-01

    CD1d expressing dendritic cells (DCs) are good glyco-lipid antigen presenting cells for NKT cells. However, resting B cells are very weak stimulators for NKT cells. Although ?-galactosylceramide (?-GalCer) loaded B cells can activate NKT cells, it is not well defined whether B cells interfere NKT cell stimulating activity of DCs. Unexpectedly, we found in this study that B cells can promote Th1-skewed NKT cell response, which means a increased level of IFN-? by NKT cells, concomitant with a d...

  12. Molecular characterization of neoplastic and normal "sister" lymphoblastoid B-cell lines from chronic lymphocytic leukemia

    DEFF Research Database (Denmark)

    Lanemo Myhrinder, Anna; Hellqvist, Eva; Bergh, Ann-Charlotte

    2013-01-01

    Chronic lymphocytic leukemia (CLL) B-cells resemble self-renewing CD5 + B-cells carrying auto/xeno-antigen-reactive B-cell receptors (BCRs) and multiple innate pattern-recognition receptors, such as Toll-like receptors and scavenger receptors. Integration of signals from BCRs with multiple surface...... a comprehensive genotypic and phenotypic characterization of available CLL and normal B-cell-derived lymphoblastoid cell lines (LCLs) from the same individuals (n = 17). Authenticity and verification studies of CLL-patient origin were done by IGHV sequencing, fluorescence in situ hybridization (FISH) and DNA...

  13. Human B cells produce chemokine CXCL10 in the presence of Mycobacterium tuberculosis specific T cells

    DEFF Research Database (Denmark)

    Hoff, Soren T; Salman, Ahmed M; Ruhwald, Morten

    2015-01-01

    BACKGROUND: The role of B cells in human host response to Mycobacterium tuberculosis (Mtb) infection is still controversial, but recent evidence suggest that B cell follicle like structures within the lung may influence host responses through regulation of the local cytokine environment. A candid......BACKGROUND: The role of B cells in human host response to Mycobacterium tuberculosis (Mtb) infection is still controversial, but recent evidence suggest that B cell follicle like structures within the lung may influence host responses through regulation of the local cytokine environment...

  14. Atkins' molecules

    CERN Document Server

    Atkins, Peters

    2003-01-01

    Originally published in 2003, this is the second edition of a title that was called 'the most beautiful chemistry book ever written'. In it, we see the molecules responsible for the experiences of our everyday life - including fabrics, drugs, plastics, explosives, detergents, fragrances, tastes, and sex. With engaging prose Peter Atkins gives a non-technical account of an incredible range of aspects of the world around us, showing unexpected connections, and giving an insight into how this amazing world can be understood in terms of the atoms and molecules from which it is built. The second edition includes dozens of extra molecules, graphical presentation, and an even more accessible and enthralling account of the molecules themselves.

  15. Interstellar Molecules

    Science.gov (United States)

    Solomon, Philip M.

    1973-01-01

    Radioastronomy reveals that clouds between the stars, once believed to consist of simple atoms, contain molecules as complex as seven atoms and may be the most massive objects in our Galaxy. (Author/DF)

  16. Radioimmunotherapy of B-cell non-Hodgkin’s lymphoma

    Directory of Open Access Journals (Sweden)

    Caroline eBodet-Milin

    2013-07-01

    Full Text Available This manuscript reviews current advances in the use of radioimmunotherapy (RIT for the treatment of B-cell non-Hodgkin’s lymphoma (NHL. RIT has been in use for more than 20 years and has progressed significantly with the discovery of new molecular targets, the development of new stable chelates, the humanization of monoclonal antibodies (MAbs, and the use of pretargeting techniques. Today, two products targeting the CD20 antigen are approved: 131I-tositumomab, (Bexxar® and 90Y-ibritumomab tiuxetan, (Zevalin®. 131I-tositumomab is available in the United States, and 90Y-ibritumumab tiuxetan in Europe, the United States, Asia, and Africa. RIT can be integrated in clinical practice using non-ablative activities for treatment of patients with relapsed or refractory follicular lymphoma (FL or as consolidation after induction chemotherapy in front-line treatment in FL patients. Despite the lack of phase III studies to clearly define the efficacy of RIT in the management of B lymphoma in the era of rituximab-based therapy, RIT efficacy in NHL has been demonstrated. In relapsing refractory FL and transformed NHL, RIT as a monotherapy induces around 30% complete response with a possibility of durable remissions. RIT consolidation after induction therapy significantly improves the quality of the response. Dose-limiting toxicity of RIT is hematological, depending on bone marrow involvement and prior treatment. Non-hematological toxicity is generally low. Different studies have been published assessing innovative protocols of RIT or new indications, in particular treatment in patients with aggressive lymphomas. High-dose treatment, RIT as consolidation after different therapeutic induction modalities, RIT in first-line treatment or fractionated RIT showed promising results. New MAbs, in particular humanized MAbs, or combinations of naked and radiolabeled MAbs, also appear promising. Personalized dosimetry protocols should be developed to determine

  17. Metformin inhibits cell cycle progression of B-cell chronic lymphocytic leukemia cells.

    Science.gov (United States)

    Bruno, Silvia; Ledda, Bernardetta; Tenca, Claudya; Ravera, Silvia; Orengo, Anna Maria; Mazzarello, Andrea Nicola; Pesenti, Elisa; Casciaro, Salvatore; Racchi, Omar; Ghiotto, Fabio; Marini, Cecilia; Sambuceti, Gianmario; DeCensi, Andrea; Fais, Franco

    2015-09-08

    B-cell chronic lymphocytic leukemia (CLL) was believed to result from clonal accumulation of resting apoptosis-resistant malignant B lymphocytes. However, it became increasingly clear that CLL cells undergo, during their life, iterative cycles of re-activation and subsequent clonal expansion. Drugs interfering with CLL cell cycle entry would be greatly beneficial in the treatment of this disease. 1, 1-Dimethylbiguanide hydrochloride (metformin), the most widely prescribed oral hypoglycemic agent, inexpensive and well tolerated, has recently received increased attention for its potential antitumor activity. We wondered whether metformin has apoptotic and anti-proliferative activity on leukemic cells derived from CLL patients. Metformin was administered in vitro either to quiescent cells or during CLL cell activation stimuli, provided by classical co-culturing with CD40L-expressing fibroblasts. At doses that were totally ineffective on normal lymphocytes, metformin induced apoptosis of quiescent CLL cells and inhibition of cell cycle entry when CLL were stimulated by CD40-CD40L ligation. This cytostatic effect was accompanied by decreased expression of survival- and proliferation-associated proteins, inhibition of signaling pathways involved in CLL disease progression and decreased intracellular glucose available for glycolysis. In drug combination experiments, metformin lowered the apoptotic threshold and potentiated the cytotoxic effects of classical and novel antitumor molecules. Our results indicate that, while CLL cells after stimulation are in the process of building their full survival and cycling armamentarium, the presence of metformin affects this process.

  18. B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and classical Burkitt's lymphoma: A case report and review

    OpenAIRE

    Chettiankandy, Tabita Joy; Tupkari, Jagdish Vishnu; Kumar, Keshav; Ahire, Manisha Sandeep

    2016-01-01

    B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma (DLBCL) and classical Burkitt's lymphoma (BL), is a diagnostic provisional category in the World Health Organization 2008 classification of lymphomas. This category was designed as a measure to accommodate borderline cases that cannot be reliably classified into a single distinct disease entity after all available morphological, immunophenotypical and molecular studies have been performed. Typica...

  19. Prediction of linear B-cell epitopes of hepatitis C virus for vaccine development

    Science.gov (United States)

    2015-01-01

    Background High genetic heterogeneity in the hepatitis C virus (HCV) is the major challenge of the development of an effective vaccine. Existing studies for developing HCV vaccines have mainly focused on T-cell immune response. However, identification of linear B-cell epitopes that can stimulate B-cell response is one of the major tasks of peptide-based vaccine development. Owing to the variability in B-cell epitope length, the prediction of B-cell epitopes is much more complex than that of T-cell epitopes. Furthermore, the motifs of linear B-cell epitopes in different pathogens are quite different (e. g. HCV and hepatitis B virus). To cope with this challenge, this work aims to propose an HCV-customized sequence-based prediction method to identify B-cell epitopes of HCV. Results This work establishes an experimentally verified dataset comprising the B-cell response of HCV dataset consisting of 774 linear B-cell epitopes and 774 non B-cell epitopes from the Immune Epitope Database. An interpretable rule mining system of B-cell epitopes (IRMS-BE) is proposed to select informative physicochemical properties (PCPs) and then extracts several if-then rule-based knowledge for identifying B-cell epitopes. A web server Bcell-HCV was implemented using an SVM with the 34 informative PCPs, which achieved a training accuracy of 79.7% and test accuracy of 70.7% better than the SVM-based methods for identifying B-cell epitopes of HCV and the two general-purpose methods. This work performs advanced analysis of the 34 informative properties, and the results indicate that the most effective property is the alpha-helix structure of epitopes, which influences the connection between host cells and the E2 proteins of HCV. Furthermore, 12 interpretable rules are acquired from top-five PCPs and achieve a sensitivity of 75.6% and specificity of 71.3%. Finally, a conserved promising vaccine candidate, PDREMVLYQE, is identified for inclusion in a vaccine against HCV. Conclusions This work

  20. B-cell receptor signaling as a driver of lymphoma development and evolution.

    Science.gov (United States)

    Niemann, Carsten U; Wiestner, Adrian

    2013-12-01

    The B-cell receptor (BCR) is essential for normal B-cell development and maturation. In an increasing number of B-cell malignancies, BCR signaling is implicated as a pivotal pathway in tumorigenesis. Mechanisms of BCR activation are quite diverse and range from chronic antigenic drive by microbial or viral antigens to autostimulation of B-cells by self-antigens to activating mutations in intracellular components of the BCR pathway. Hepatitis C virus infection can lead to the development of splenic marginal zone lymphoma, while Helicobacter pylori infection is associated with the development of mucosa-associated lymphoid tissue lymphomas. In some of these cases, successful treatment of the infection removes the inciting antigen and results in resolution of the lymphoma. Chronic lymphocytic leukemia has been recognized for decades as a malignancy of auto-reactive B-cells and its clinical course is in part determined by the differential response of the malignant cells to BCR activation. In a number of B-cell malignancies, activating mutations in signal transduction components of the BCR pathway have been identified; prominent examples are activated B-cell-like (ABC) diffuse large B-cell lymphomas (DLBCL) that carry mutations in CD79B and CARD11 and display chronic active BCR signaling resulting in constitutive activation of the NF-κB pathway. Despite considerable heterogeneity in biology and clinical course, many mature B-cell malignancies are highly sensitive to kinase inhibitors that disrupt BCR signaling. Thus, targeted therapy through inhibition of BCR signaling is emerging as a new treatment paradigm for many B-cell malignancies. Here, we review the role of the BCR in the pathogenesis of B-cell malignancies and summarize clinical results of the emerging class of kinase inhibitors that target this pathway. Copyright © 2013. Published by Elsevier Ltd.

  1. IL-15 expression on RA synovial fibroblasts promotes B cell survival.

    Directory of Open Access Journals (Sweden)

    Marta Benito-Miguel

    Full Text Available INTRODUCTION: The purpose of this study was to examine the role of RA Synovial Fibroblast (RASFib IL-15 expression on B cell survival. METHODS: Magnetically sorted peripheral blood memory B cells from 15 healthy subjects were cocultured with RASFib. RESULTS: RASFib constitutively expressed membrane IL-15. Survival of isolated B cells cultured for 6 days, below 5%, was extended in coculture with RASFib to 52+/-8% (p<0.001. IL-15 neutralizing agents but not isotype controls, reduced this rate to 31+/-6% (p<0.05. Interestingly, rhIL-15 had no effect on isolated B cells but significantly increased their survival in coculture with RASFib. In parallel, B cell IL-15R chains were upregulated in cocultures. BAFF and VCAM-1, that are expressed on RASFib, were tested as potential candidates involved in upregulating B cell IL-15R. Culture of B cells in the presence of rhBAFF or rhVCAM-1 resulted in significantly increased survival, together with upregulation of all three IL-15R chains; in parallel, rhIL-15 potentiated the anti-apoptotic effect of BAFF and VCAM-1. Both BAFF and VCAM-1 neutralizing agents downmodulated the effect of RASFib on B cell survival and IL-15R expression. In parallel, rhIL-15 had a lower effect on the survival of B cells cocultured with RASFib in the presence of BAFF or VCAM-1 neutralizing agents. Peripheral blood B cells from 15 early RA patients demonstrated an upregulated IL-15R and increased survival in cocultures. CONCLUSION: IL-15 expression on RASFib significantly contributes to the anti-apoptotic effect of RASFib on B cells. IL-15 action is facilitated by BAFF and VCAM-1 expressed on RASFib, through an upregulation of IL-15R chains.

  2. The ibrutinib B-cell proliferation inhibition is potentiated in vitro by dexamethasone: Application to chronic lymphocytic leukemia.

    Science.gov (United States)

    Manzoni, Delphine; Catallo, Régine; Chebel, Amel; Baseggio, Lucile; Michallet, Anne-Sophie; Roualdes, Olivier; Magaud, Jean-Pierre; Salles, Gilles; Ffrench, Martine

    2016-08-01

    New B-cell receptor-targeted therapies such as ibrutinib, a Bruton tyrosine kinase inhibitor, are now proposed for lymphoid pathologies. The putative benefits of its combination with glucocorticoids were evaluated here. We compared the effects of dexamethasone (DXM), ibrutinib and their in vitro combination on proliferation and metabolic stress markers in stimulated normal B-lymphocytes and in malignant lymphocytes from chronic lymphocytic leukemia (CLL) patients. In both cellular models, cell cycle progression was globally inhibited by DXM and/or ibrutinib. This inhibition was significantly amplified by DXM addition to ibrutinib and was related to a significant decrease in the expression of the cell cycle regulatory proteins CDK4 and cyclin E. Apoptosis increased especially with DXM/ibrutinib combination and was associated with a significant decrease in Mcl-1 expression. Treatment effects on metabolic stress were evaluated by DNA damage recognition after 53BP1 foci labeling. The percentage of cells with more than five 53BP1 foci decreased significantly with ibrutinib in normal and CLL lymphocytes. This decrease was strongly reinforced, in CLL, by DXM addition. Our data indicated that, in vitro, DXM potentiated antiproliferative effects of ibrutinib and decreased DNA damage in lymphoid B-cells. Thus their combination may be proposed for CLL treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Association of CLEC16A with human common variable immunodeficiency disorder and role in murine B cells.

    Science.gov (United States)

    Li, Jin; Jørgensen, Silje F; Maggadottir, S Melkorka; Bakay, Marina; Warnatz, Klaus; Glessner, Joseph; Pandey, Rahul; Salzer, Ulrich; Schmidt, Reinhold E; Perez, Elena; Resnick, Elena; Goldacker, Sigune; Buchta, Mary; Witte, Torsten; Padyukov, Leonid; Videm, Vibeke; Folseraas, Trine; Atschekzei, Faranaz; Elder, James T; Nair, Rajan P; Winkelmann, Juliane; Gieger, Christian; Nöthen, Markus M; Büning, Carsten; Brand, Stephan; Sullivan, Kathleen E; Orange, Jordan S; Fevang, Børre; Schreiber, Stefan; Lieb, Wolfgang; Aukrust, Pål; Chapel, Helen; Cunningham-Rundles, Charlotte; Franke, Andre; Karlsen, Tom H; Grimbacher, Bodo; Hakonarson, Hakon; Hammarström, Lennart; Ellinghaus, Eva

    2015-04-20

    Common variable immunodeficiency disorder (CVID) is the most common symptomatic primary immunodeficiency in adults, characterized by B-cell abnormalities and inadequate antibody response. CVID patients have considerable autoimmune comorbidity and we therefore hypothesized that genetic susceptibility to CVID may overlap with autoimmune disorders. Here, in the largest genetic study performed in CVID to date, we compare 778 CVID cases with 10,999 controls across 123,127 single-nucleotide polymorphisms (SNPs) on the Immunochip. We identify the first non-HLA genome-wide significant risk locus at CLEC16A (rs17806056, P=2.0 × 10(-9)) and confirm the previously reported human leukocyte antigen (HLA) associations on chromosome 6p21 (rs1049225, P=4.8 × 10(-16)). Clec16a knockdown (KD) mice showed reduced number of B cells and elevated IgM levels compared with controls, suggesting that CLEC16A may be involved in immune regulatory pathways of relevance to CVID. In conclusion, the CLEC16A associations in CVID represent the first robust evidence of non-HLA associations in this immunodeficiency condition.

  4. Genetic alterations in B-cell non-Hodgkin's lymphoma

    Directory of Open Access Journals (Sweden)

    Magić Zvonko

    2005-01-01

    Full Text Available Background. Although the patients with diagnosed B-NHL are classified into the same disease stage on the basis of clinical, histopathological, and immunological parameters, they respond significantly different to the applied treatment. This points out the possibility that within the same group of lymphoma there are different diseases at molecular level. For that reason many studies deal with the detection of gene alterations in lymphomas to provide a better framework for diagnosis and treatment of these hematological malignancies. Aim. To define genetic alterations in the B-NHL with highest possibilities for diagnostic purposes and molecular detection of MRD. Methods. Formalin fixed and paraffin embedded lymph node tissues from 45 patients were examined by different PCR techniques for the presence of IgH and TCR γ gene rearrangement; K-ras and H-ras mutations; c-myc amplification and bcl-2 translocation. There were 34 cases of B-cell non-Hodgkin’s lymphoma (B-NHL, 5 cases of T-cell non-Hodgkin’s lymphoma (T-NHL and 6 cases of chronic lymphadenitis (CL. The mononuclear cell fraction of the peripheral blood of 12 patients with B-NHL was analyzed for the presence of monoclonality at the time of diagnosis and in 3 to 6 months time intervals after an autologous bone marrow transplantation (BMT. Results. The monoclonality of B-lymphocytes, as evidenced by DNA fragment length homogeneity, was detected in 88 % (30/34 of B-NHL, but never in CL, T-NHL, or in normal PBL. Bcl-2 translocation was detected in 7/31 (22.6% B-NHL specimens, c-myc amplification 9/31 (29%, all were more than doubled, K-ras mutations in 1/31 (3.23% and H-ras mutations in 2/31 (6.45% of the examined B-NHL samples. In the case of LC and normal PBL, however, these gene alterations were not detected. All the patients (12 with B-NHL had dominant clone of B-lymphocyte in the peripheral blood at the time of diagnosis while only in 2 of 12 patients MRD was detected 3 or 6 months after

  5. Logical analysis of diffuse large B-cell lymphomas.

    Science.gov (United States)

    Alexe, G; Alexe, S; Axelrod, D E; Hammer, P L; Weissmann, D

    2005-07-01

    The goal of this study is to re-examine the oligonucleotide microarray dataset of Shipp et al., which contains the intensity levels of 6817 genes of 58 patients with diffuse large B-cell lymphoma (DLBCL) and 19 with follicular lymphoma (FL), by means of the combinatorics, optimisation, and logic-based methodology of logical analysis of data (LAD). The motivations for this new analysis included the previously demonstrated capabilities of LAD and its expected potential (1) to identify different informative genes than those discovered by conventional statistical methods, (2) to identify combinations of gene expression levels capable of characterizing different types of lymphoma, and (3) to assemble collections of such combinations that if considered jointly are capable of accurately distinguishing different types of lymphoma. The central concept of LAD is a pattern or combinatorial biomarker, a concept that resembles a rule as used in decision tree methods. LAD is able to exhaustively generate the collection of all those patterns which satisfy certain quality constraints, through a systematic combinatorial process guided by clear optimization criteria. Then, based on a set covering approach, LAD aggregates the collection of patterns into classification models. In addition, LAD is able to use the information provided by large collections of patterns in order to extract subsets of variables, which collectively are able to distinguish between different types of disease. For the differential diagnosis of DLBCL versus FL, a model based on eight significant genes is constructed and shown to have a sensitivity of 94.7% and a specificity of 100% on the test set. For the prognosis of good versus poor outcome among the DLBCL patients, a model is constructed on another set consisting also of eight significant genes, and shown to have a sensitivity of 87.5% and a specificity of 90% on the test set. The genes selected by LAD also work well as a basis for other kinds of statistical

  6. An age-related numerical and functional deficit in CD19(+) CD24(hi) CD38(hi) B cells is associated with an increase in systemic autoimmunity.

    Science.gov (United States)

    Duggal, Niharika A; Upton, Jane; Phillips, Anna C; Sapey, Elizabeth; Lord, Janet M

    2013-10-01

    Autoimmunity increases with aging indicative of reduced immune tolerance, but the mechanisms involved are poorly defined. In recent years, subsets of B cells with immunoregulatory properties have been identified in murine models of autoimmune disorders, and these cells downregulate immune responses via secretion of IL10. In humans, immature transitional B cells with a CD19(+) CD24(hi) CD38(hi) phenotype have been reported to regulate immune responses via IL10 production. We found the frequency and numbers of CD19(+) CD24(hi) CD38(hi) cells were reduced in the PBMC pool with age. IL10 expression and secretion following activation via either CD40, or Toll-like receptors was also impaired in CD19(+) CD24(hi) CD38(hi) B cells from healthy older donors. When investigating the mechanisms involved, we found that CD19(+) CD24(hi) CD38(hi) B-cell function was compromised by age-related effects on both T cells and B cells: specifically, CD40 ligand expression was lower in CD4 T cells from older donors following CD3 stimulation, and signalling through CD40 was impaired in CD19(+) CD24(hi) CD38(hi) B cells from elders as evidenced by reduced phosphorylation (Y705) and activation of STAT3. However, there was no age-associated change in expression of costimulatory molecules CD80 and CD86 on CD19(+) CD24(hi) CD38(hi) cells, suggesting IL10-dependent immune suppression is impaired, but contact-dependent suppressive capacity is intact with age. Finally, we found a negative correlation between CD19(+) CD24(hi) CD38(hi) B-cell IL10 production and autoantibody (Rheumatoid factor) levels in older adults. We therefore propose that an age-related decline in CD19(+) CD24(hi) CD38(hi) B cell number and function may contribute towards the increased autoimmunity and reduced immune tolerance seen with aging. © 2013 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  7. The FOX and the mutants in mature human B cells and DLBCL: The role of FOXP1 in mature human B cell biology and lymphomagenesis & prevalence of oncogenic MyD88 and CD79B mutations in diffuse large B cell lymphoma

    NARCIS (Netherlands)

    van Keimpema, M.

    2015-01-01

    The transcription factor FOXP1 is prominently expressed in mature B cells and is a potential oncogene in B cell non-Hodgkin lymphomas; however, the functions of FOXP1 in mature B cells and B cell lymphomagenesis have not yet been fully explored. In the first part of this thesis, the roles of FOXP1

  8. Adult high-grade B-cell lymphoma with Burkitt lymphoma signature: genomic features and potential therapeutic targets.

    Science.gov (United States)

    Bouska, Alyssa; Bi, Chengfeng; Lone, Waseem; Zhang, Weiwei; Kedwaii, Ambreen; Heavican, Tayla; Lachel, Cynthia M; Yu, Jiayu; Ferro, Roberto; Eldorghamy, Nanees; Greiner, Timothy C; Vose, Julie; Weisenburger, Dennis D; Gascoyne, Randy D; Rosenwald, Andreas; Ott, German; Campo, Elias; Rimsza, Lisa M; Jaffe, Elaine S; Braziel, Rita M; Siebert, Reiner; Miles, Rodney R; Dave, Sandeep; Reddy, Anupama; Delabie, Jan; Staudt, Louis M; Song, Joo Y; McKeithan, Timothy W; Fu, Kai; Green, Michael; Chan, Wing C; Iqbal, Javeed

    2017-10-19

    The adult high-grade B-cell lymphomas sharing molecular features with Burkitt lymphoma (BL) are highly aggressive lymphomas with poor clinical outcome. High-resolution structural and functional genomic analysis of adult Burkitt lymphoma (BL) and high-grade B-cell lymphoma with BL gene signature (adult-molecularly defined BL [mBL]) revealed the MYC-ARF-p53 axis as the primary deregulated pathway. Adult-mBL had either unique or more frequent genomic aberrations (del13q14, del17p, gain8q24, and gain18q21) compared with pediatric-mBL, but shared commonly mutated genes. Mutations in genes promoting the tonic B-cell receptor (BCR)→PI3K pathway ( TCF3 and ID3 ) did not differ by age, whereas effectors of chronic BCR→NF-κB signaling were associated with adult-mBL. A subset of adult-mBL had BCL2 translocation and mutation and elevated BCL2 mRNA and protein expression, but had a mutation profile similar to mBL. These double-hit lymphomas may have arisen from a tumor precursor that acquired both BCL2 and MYC translocations and/or KMT2D ( MLL2 ) mutation. Gain/amplification of MIR17HG and its paralogue loci was observed in 50% of adult-mBL. In vitro studies suggested miR-17∼92 's role in constitutive activation of BCR signaling and sensitivity to ibrutinib. Overall integrative analysis identified an interrelated gene network affected by copy number and mutation, leading to disruption of the p53 pathway and the BCR→PI3K or NF-κB activation, which can be further exploited in vivo by small-molecule inhibitors for effective therapy in adult-mBL.

  9. Mouse dendritic cells pulsed with capsular polysaccharide induce resistance to lethal pneumococcal challenge: roles of T cells and B cells.

    Directory of Open Access Journals (Sweden)

    Noam Cohen

    Full Text Available Mice are exceedingly sensitive to intra-peritoneal (IP challenge with some virulent pneumococci (LD50 = 1 bacterium. To investigate how peripheral contact with bacterial capsular polysaccharide (PS antigen can induce resistance, we pulsed bone marrow dendritic cells (BMDC of C57BL/6 mice with type 4 or type 3 PS, injected the BMDC intra-foot pad (IFP and challenged the mice IP with supra-lethal doses of pneumococci. We examined the responses of T cells and B cells in the draining popliteal lymph node and measured the effects on the bacteria in the peritoneum and blood. We now report that: 1 The PS co-localized with MHC molecules on the BMDC surface; 2 PS-specific T and B cell proliferation and IFNγ secretion was detected in the draining popliteal lymph nodes on day 4; 3 Type-specific resistance to lethal IP challenge was manifested only after day 5; 4 Type-specific IgM and IgG antibodies were detected in the sera of only some of the mice, but B cells were essential for resistance; 5 Control mice vaccinated with a single injection of soluble PS did not develop a response in the draining popliteal lymph node and were not protected; 6 Mice injected with unpulsed BMDC also did not resist challenge: In unprotected mice, pneumococci entered the blood shortly after IP inoculation and multiplied exponentially in both blood and peritoneum killing the mice within 20 hours. Mice vaccinated with PS-pulsed BMDC trapped the bacteria in the peritoneum. The trapped bacteria proliferated exponentially IP, but died suddenly at 18-20 hours. Thus, a single injection of PS antigen associated with intact BMDC is a more effective vaccine than the soluble PS alone. This model system provides a platform for studying novel aspects of PS-targeted vaccination.

  10. Function of Bruton's tyrosine kinase during B cell development is partially independent of its catalytic activity

    NARCIS (Netherlands)

    S. Middendorp; G.M. Dingjan (Gemma); A. Maas (Alex); K. Dahlenborg; R.W. Hendriks (Rudi)

    2003-01-01

    textabstractThe Tec family member Bruton's tyrosine kinase (Btk) is a cytoplasmic protein tyrosine kinase that transduces signals from the pre-B and B cell receptor (BCR). Btk is involved in pre-B cell maturation by regulating IL-7 responsiveness, cell surface phenotype changes,

  11. EBV-positive diffuse large B-cell lymphoma of the elderly

    NARCIS (Netherlands)

    C.Y. Ok (Chi Young); T.G. Papathomas (Thomas); L.J. Medeiros (L. Jeffrey); K.H. Young (Ken)

    2013-01-01

    textabstractEpstein-Barr virus (EBV) positive diffuse large B-cell lymphoma (DLBCL) of the elderly, initially described in 2003, is a provisional entity in the 2008World Health Organization classification system and is defined as an EBV-positive monoclonal large B-cell proliferation that occurs in

  12. Docking of B-cell epitope antigen to specific hepatitis B antibody

    Indian Academy of Sciences (India)

    The interaction of pres1 region of hepatitis B virus B-cell epitope antigen with specific hepatitis B neutralizing monoclonal antibody was examined by docking study. We modelled the 3D complex structure of B-cell epitope antigen residues CTTPAQGNSMFPSCCCTKPTDGNCY by homology modelling and docked it with the ...

  13. Evaluating the B-cell density with various activation functions using White Noise Path Integral Approach

    Science.gov (United States)

    Aban, C. J. G.; Bacolod, R. O.; Confesor, M. N. P.

    2015-06-01

    A The White Noise Path Integral Approach is used in evaluating the B-cell density or the number of B-cell per unit volume for a basic type of immune system response based on the modeling done by Perelson and Wiegel. From the scaling principles of Perelson [1], the B- cell density is obtained where antigens and antibodies mutates and activation function f(|S-SA|) is defined describing the interaction between a specific antigen and a B-cell. If the activation function f(|S-SA|) is held constant, the major form of the B-cell density evaluated using white noise analysis is similar to the form of the B-cell density obtained by Perelson and Wiegel using a differential approach.A piecewise linear functionis also used to describe the activation f(|S-SA|). If f(|S-SA|) is zero, the density decreases exponentially. If f(|S-SA|) = S-SA-SB, the B- cell density increases exponentially until it reaches a certain maximum value. For f(|S-SA|) = 2SA-SB-S, the behavior of B-cell density is oscillating and remains to be in small values.

  14. Changes in Circulating B Cell Subsets Associated with Aging and Acute SIV Infection in Rhesus Macaques.

    Science.gov (United States)

    Chang, W L William; Gonzalez, Denise F; Kieu, Hung T; Castillo, Luis D; Messaoudi, Ilhem; Shen, Xiaoying; Tomaras, Georgia D; Shacklett, Barbara L; Barry, Peter A; Sparger, Ellen E

    2017-01-01

    Aging and certain viral infections can negatively impact humoral responses in humans. To further develop the nonhuman primate (NHP) model for investigating B cell dynamics in human aging and infectious disease, a flow cytometric panel was developed to characterize circulating rhesus B cell subsets. Significant differences between human and macaque B cells included the proportions of cells within IgD+ and switched memory populations and a prominent CD21-CD27+ unswitched memory population detected only in macaques. We then utilized the expanded panel to analyze B cell alterations associated with aging and acute simian immunodeficiency virus (SIV) infection in the NHP model. In the aging study, distinct patterns of B cell subset frequencies were observed for macaques aged one to five years compared to those between ages 5 and 30 years. In the SIV infection study, B cell frequencies and absolute number were dramatically reduced following acute infection, but recovered within four weeks of infection. Thereafter, the frequencies of activated memory B cells progressively increased; these were significantly correlated with the magnitude of SIV-specific IgG responses, and coincided with impaired maturation of anti-SIV antibody avidity, as previously reported for HIV-1 infection. These observations further validate the NHP model for investigation of mechanisms responsible for B cells alterations associated with immunosenescence and infectious disease.

  15. B-cell lymphoma in a dog with ehrlichiosis (Ehrlichia canis) and systemic histoplasmosis (Histoplasma capsulatum).

    Science.gov (United States)

    Brunker, Jill D; Hoover, John P

    2007-03-01

    A mixed breed dog treated for ehrlichiosis and systemic histoplasmosis developed a refractory thrombocytopenia. When an abdominal mass was detected, exploratory laparotomy and biopsies confirmed lymphoma, which on immunohistochemical stains was determined to be of B-cell origin. Conceivably, the B-cell lymphoma in this dog was associated with chronic inflammation from ehrlichiosis, histoplasmosis, or both.

  16. The VP7 Outer Capsid Protein of Rotavirus Induces Polyclonal B-Cell Activation

    Science.gov (United States)

    Blutt, Sarah E.; Crawford, Sue E.; Warfield, Kelly L.; Lewis, Dorothy E.; Estes, Mary K.; Conner, Margaret E.

    2004-01-01

    The early response to a homologous rotavirus infection in mice includes a T-cell-independent increase in the number of activated B lymphocytes in the Peyer's patches. The mechanism of this activation has not been previously determined. Since rotavirus has a repetitively arranged triple-layered capsid and repetitively arranged antigens can induce activation of B cells, one or more of the capsid proteins could be responsible for the initial activation of B cells during infection. To address this question, we assessed the ability of rotavirus and virus-like particles to induce B-cell activation in vivo and in vitro. Using infectious rotavirus, inactivated rotavirus, noninfectious but replication-competent virus, and virus-like particles, we determined that neither infectivity nor RNA was necessary for B-cell activation but the presence of the rotavirus outer capsid protein, VP7, was sufficient for murine B-cell activation. Preincubation of the virus with neutralizing VP7 antibodies inhibited B-cell activation. Polymyxin B treatment and boiling of the virus preparation were performed, which ruled out possible lipopolysaccharide contamination as the source of activation and confirmed that the structural conformation of VP7 is important for B-cell activation. These findings indicate that the structure and conformation of the outer capsid protein, VP7, initiate intestinal B-cell activation during rotavirus infection. PMID:15194774

  17. Toll-like receptors in the pathogenesis of human B cell malignancies

    NARCIS (Netherlands)

    Isaza-Correa, Johana M.; Liang, Zheng; van den Berg, Anke; Diepstra, Arjan; Visser, Lydia

    2014-01-01

    Toll-like receptors (TLRs) are important players in B-cell activation, maturation and memory and may be involved in the pathogenesis of B-cell lymphomas. Accumulating studies show differential expression in this heterogeneous group of cancers. Stimulation with TLR specific ligands, or agonists of

  18. Differentiation of purified malignant B cells induced by PMA or by activated normal T cells

    NARCIS (Netherlands)

    van Kooten, C.; Rensink, I.; Aarden, L.; van Oers, R.

    1993-01-01

    We studied the in vitro differentiation (immunoglobulin production) of purified malignant B cells of 21 patients with different B-cell malignancies, including chronic lymphocytic leukemia (CLL), prolymphocytic leukemia (PLL), hairy cell leukemia (HCL) and non-Hodgkin lymphoma (NHL). Direct

  19. DEFECTS IN INSULIN-SECRETION IN NIDDM - B-CELL GLUCOSE INSENSITIVITY OR GLUCOSE TOXICITY

    NARCIS (Netherlands)

    VANHAEFTEN, TW

    In NIDDM, first-phase insulin release to glucose is (almost) absent. However, in contrast to older studies which suggested that in NIDDM the B-cell is ''blind'' for glucose, recent evidence indicates that the B-cell is not insensitive for glucose as far as second phase release is concerned. This

  20. Excessive amounts of mu heavy chain block B-cell development.

    Science.gov (United States)

    Zhu, Lingqiao; Chang, Cheong-Hee; Dunnick, Wesley

    2011-09-01

    Antigen-independent B-cell development occurs in several stages that depend on the expression of Ig heavy and light chain. We identified a line of mice that lacked mature B cells in the spleen. This mouse line carried approximately 11 copies of a transgene of the murine heavy chain constant region locus, and B-lineage cells expressed excessive amounts of the intracellular μ heavy chain. B-cell development failed in the bone marrow at the pro/pre B-cell transition, and examination of other lines with various copy numbers of the same transgene suggested that deficiencies in B-cell development increased with increased transgene copy number. Expression of a transgenic (Tg) light chain along with the Tg μ heavy chain led to minimal rescue of B-cell development in the bone marrow and B cells in the spleen. There are several potential mechanisms for the death of pro/pre B cells as a consequence of excess heavy chain expression.

  1. Microfluidic squeezing for intracellular antigen loading in polyclonal B-cells as cellular vaccines

    Science.gov (United States)

    Lee Szeto, Gregory; van Egeren, Debra; Worku, Hermoon; Sharei, Armon; Alejandro, Brian; Park, Clara; Frew, Kirubel; Brefo, Mavis; Mao, Shirley; Heimann, Megan; Langer, Robert; Jensen, Klavs; Irvine, Darrell J.

    2015-05-01

    B-cells are promising candidate autologous antigen-presenting cells (APCs) to prime antigen-specific T-cells both in vitro and in vivo. However to date, a significant barrier to utilizing B-cells as APCs is their low capacity for non-specific antigen uptake compared to “professional” APCs such as dendritic cells. Here we utilize a microfluidic device that employs many parallel channels to pass single cells through narrow constrictions in high throughput. This microscale “cell squeezing” process creates transient pores in the plasma membrane, enabling intracellular delivery of whole proteins from the surrounding medium into B-cells via mechano-poration. We demonstrate that both resting and activated B-cells process and present antigens delivered via mechano-poration exclusively to antigen-specific CD8+T-cells, and not CD4+T-cells. Squeezed B-cells primed and expanded large numbers of effector CD8+T-cells in vitro that produced effector cytokines critical to cytolytic function, including granzyme B and interferon-γ. Finally, antigen-loaded B-cells were also able to prime antigen-specific CD8+T-cells in vivo when adoptively transferred into mice. Altogether, these data demonstrate crucial proof-of-concept for mechano-poration as an enabling technology for B-cell antigen loading, priming of antigen-specific CD8+T-cells, and decoupling of antigen uptake from B-cell activation.

  2. Secondary immunization generates clonally related antigen-specific plasma cells and memory B cells.

    Science.gov (United States)

    Frölich, Daniela; Giesecke, Claudia; Mei, Henrik E; Reiter, Karin; Daridon, Capucine; Lipsky, Peter E; Dörner, Thomas

    2010-09-01

    Rechallenge with T cell-dependent Ags induces memory B cells to re-enter germinal centers (GCs) and undergo further expansion and differentiation into plasma cells (PCs) and secondary memory B cells. It is currently not known whether the expanded population of memory B cells and PCs generated in secondary GCs are clonally related, nor has the extent of proliferation and somatic hypermutation of their precursors been delineated. In this study, after secondary tetanus toxoid (TT) immunization, TT-specific PCs increased 17- to 80-fold on days 6-7, whereas TT-specific memory B cells peaked (delayed) on day 14 with a 2- to 22-fold increase. Molecular analyses of V(H)DJ(H) rearrangements of individual cells revealed no major differences of gene usage and CDR3 length between TT-specific PCs and memory B cells, and both contained extensive evidence of somatic hypermutation with a pattern consistent with GC reactions. This analysis identified clonally related TT-specific memory B cells and PCs. Within clusters of clonally related cells, sequences shared a number of mutations but also could contain additional base pair changes. The data indicate that although following secondary immunization PCs can derive from memory B cells without further somatic hypermutation, in some circumstances, likely within GC reactions, asymmetric mutation can occur. These results suggest that after the fate decision to differentiate into secondary memory B cells or PCs, some committed precursors continue to proliferate and mutate their V(H) genes.

  3. Cutaneous B-cell lymphoma : classification, prognostic factors and management recommendations

    NARCIS (Netherlands)

    Senff, Nancy Johanna

    2009-01-01

    The term primary cutaneous B-cell lymphomas refers to a heterogeneous group of B-cell non-Hodgkin lymphomas, that present in the skin without evidence of extracutaneous disease at the time of diagnosis. In recent years, there has been considerable debate regarding the classification and terminology

  4. Deficiency in memory B cell compartment in a patient with infertility and recurrent pregnancy losses.

    Science.gov (United States)

    Sung, N; Byeon, H J; Garcia, M D Salazar; Skariah, A; Wu, L; Dambaeva, S; Beaman, K; Gilman-Sachs, A; Kwak-Kim, J

    2016-11-01

    Alterations in normal balance of B cell subsets have been reported in various rheumatic diseases. In this study, we report a woman with a history of recurrent pregnancy losses (RPL) and infertility who had low levels of memory B cells. A 35-year-old woman with a history of RPL and infertility was demonstrated to have increased peripheral blood CD19+ B cells with persistently low levels of memory B cell subsets. Prior to the frozen donor egg transfer cycle, prednisone and intravenous immunoglobulin G (IVIg) treatment was initiated and patient achieved dichorionic diamniotic twin pregnancies. During pregnancy, proportion (%) of switched memory B cells CD27+IgD- increased, while percent of total CD19+ B cells and CD27-IgD+ naive B cells were gradually decreased with a high dose IVIg treatment. She developed cervical incompetence at 20 weeks of gestation, received a Cesarean section at 32 weeks of gestation due to preterm labor, and delivered twin babies. B cell subset abnormalities may be associated with infertility, RPL and preterm labor, and further investigation is needed. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. A multi-scale model for correlation in B cell VDJ usage of zebrafish

    International Nuclear Information System (INIS)

    Pan, Keyao; Deem, Michael W

    2011-01-01

    The zebrafish (Danio rerio) is one of the model animals used for the study of immunology because the dynamics in the adaptive immune system of zebrafish are similar to that in higher animals. In this work, we built a multi-scale model to simulate the dynamics of B cells in the primary and secondary immune responses of zebrafish. We use this model to explain the reported correlation between VDJ usage of B cell repertoires in individual zebrafish. We use a delay ordinary differential equation (ODE) system to model the immune responses in the 6-month lifespan of a zebrafish. This mean field theory gives the number of high-affinity B cells as a function of time during an infection. The sequences of those B cells are then taken from a distribution calculated by a 'microscopic' random energy model. This generalized NK model shows that mature B cells specific to one antigen largely possess a single VDJ recombination. The model allows first-principle calculation of the probability, p, that two zebrafish responding to the same antigen will select the same VDJ recombination. This probability p increases with the B cell population size and the B cell selection intensity. The probability p decreases with the B cell hypermutation rate. The multi-scale model predicts correlations in the immune system of the zebrafish that are highly similar to that from experiment

  6. A multi-scale model for correlation in B cell VDJ usage of zebrafish

    Science.gov (United States)

    Pan, Keyao; Deem, Michael W.

    2011-10-01

    The zebrafish (Danio rerio) is one of the model animals used for the study of immunology because the dynamics in the adaptive immune system of zebrafish are similar to that in higher animals. In this work, we built a multi-scale model to simulate the dynamics of B cells in the primary and secondary immune responses of zebrafish. We use this model to explain the reported correlation between VDJ usage of B cell repertoires in individual zebrafish. We use a delay ordinary differential equation (ODE) system to model the immune responses in the 6-month lifespan of a zebrafish. This mean field theory gives the number of high-affinity B cells as a function of time during an infection. The sequences of those B cells are then taken from a distribution calculated by a 'microscopic' random energy model. This generalized NK model shows that mature B cells specific to one antigen largely possess a single VDJ recombination. The model allows first-principle calculation of the probability, p, that two zebrafish responding to the same antigen will select the same VDJ recombination. This probability p increases with the B cell population size and the B cell selection intensity. The probability p decreases with the B cell hypermutation rate. The multi-scale model predicts correlations in the immune system of the zebrafish that are highly similar to that from experiment.

  7. Adhesion molecules

    CERN Document Server

    Preedy, Victor R

    2016-01-01

    This book covers the structure and classification of adhesion molecules in relation to signaling pathways and gene expression. It discusses immunohistochemical localization, neutrophil migration, and junctional, functional, and inflammatory adhesion molecules in pathologies such as leukocyte decompression sickness and ischemia reperfusion injury. Highlighting the medical applications of current research, chapters cover diabetes, obesity, and metabolic syndrome; hypoxia; kidney disease; smoking, atrial fibrillation, and heart disease, the brain and dementia; and tumor proliferation. Finally, it looks at molecular imaging and bioinformatics, high-throughput technologies, and chemotherapy.

  8. Rituximab in the treatment of primary cutaneous B-cell lymphoma: a review.

    Science.gov (United States)

    Fernández-Guarino, M; Ortiz-Romero, P L; Fernández-Misa, R; Montalbán, C

    2014-06-01

    Rituximab is a chimeric mouse-human antibody that targets the CD20 antigen, which is found in both normal and neoplastic B cells. In recent years, it has been increasingly used to treat cutaneous B-cell lymphoma and is now considered an alternative to classic treatment (radiotherapy and surgery) of 2 types of indolent lymphoma, namely, primary cutaneous follicle center lymphoma and primary cutaneous marginal zone B-cell lymphoma. Rituximab is also administered as an alternative to polychemotherapy in the treatment of primary cutaneous large B-cell lymphoma, leg type. Its use as an alternative drug led to it being administered intralesionally, with beneficial effects. In the present article, we review the literature published on the use of rituximab to treat primary cutaneous B-cell lymphoma. Copyright © 2012 Elsevier España, S.L. and AEDV. All rights reserved.

  9. Preparation of antisera specific for human B cells by immunization of rabbits with immune complexes

    International Nuclear Information System (INIS)

    Welsh, K.I.; Turner, M.J.

    1976-01-01

    Three rabbit antisera are described which are specific without absorption (titer 1:100) for separated human B cells, as measured by complement and non-complement fixing assays. The method of production of these sera involved injections of rabbits with precipitin lines formed between 10μ1 of three separate detergent solubilized membrane preparations and 4μ1 aliquots of rabbit antisera to human B cells. In addition to being B cell specific, the three sera block the MLC reaction, inhibit aggregated IgG binding to B cells, and show differential degrees of B cell lysis when tested on a panel of separated B and T cells. These and other properties suggest that the target specificities of the antibodies are the human equivalent of the murine Ia antigens. (author)

  10. Transcriptional profiling of PBMCs unravels B cell mediated immunopathogenic imprints of HCV vasculitis.

    Science.gov (United States)

    Comstock, Emily; Kim, Cheol-Woo; Murphy, Alison; Emmanuel, Benjamin; Zhang, Xi; Sneller, Michael; Poonia, Bhawna; Kottilil, Shyamasundaran

    2017-01-01

    B cell depletion therapy using rituximab has been shown to be effective in achieving remission in patients with HCV-mixed cryoglobulinemic (MC) vasculitis. Previously, we have demonstrated abnormalities in peripheral immune cells involving neutrophils, chemotaxis, and innate immune activation among patients with HCV-MC vasculitis when compared to HCV patients without vasculitis. In this study, we evaluated the effect of B cell depletion therapy on transcriptional profiles of peripheral blood mononuclear cells before and after riruximab therapy, in order to unravel the pathogenic mechanism involved in HCV-MC vasculitis induced by abnormal B cell proliferation. DNA microarray analysis was performed using RNA from PBMCs from seven patients with HCV-MC vasculitis and seven normal volunteers. DNA was hybridized to Affymetrix U133A chips. After normalization, differentially expressed gene list with treatment was generated using partitional clustering. RT-PCR, flow cytometry, and enzyme immunoassay (EIA) was used to validate DNA microarray findings. Differentially expressed genes included B cells and non-B cell genes. Validation of genes using purified cell subsets demonstrated distinct effect of B cell depletion therapy on non-B cells, such as monocytes, T cells, and NK cells. Notably, B lymphocyte stimulator (BLyS) levels were persistently elevated in patients who subsequently relapsed. In conclusion, pathogenesis of HCV-MC vasculitis is mediated by abnormal proliferation of B cells, driven by BLyS, leading to significant effects on non-B cells in mediating symptomatology. Future therapeutics using a combination approach of B cell depletion and proliferation may be desired to achieve long-term remission.

  11. B cells are multifunctional players in multiple sclerosis pathogenesis: insights from therapeutic interventions

    Directory of Open Access Journals (Sweden)

    Nele eClaes

    2015-12-01

    Full Text Available Multiple sclerosis (MS is a severe disease of the central nervous system (CNS characterized by autoimmune inflammation and neurodegeneration. Historically, damage to the CNS was thought to be mediated predominantly by activated pro-inflammatory T cells. B cell involvement in the pathogenesis of MS was solely attributed to autoantibody production. The first clues for the involvement of antibody-independent B cell functions in MS pathology came from positive results in clinical trials of the B cell depleting treatment rituximab in patients with relapsing-remitting (RR MS. The survival of antibody-secreting plasma cells and decrease in T cell numbers indicated the importance of other B cell functions in MS such as antigen presentation, costimulation and cytokine production. Rituximab provided us with an example of how clinical trials can lead to new research opportunities concerning B cell biology. Moreover, analysis of the antibody-independent B cell functions in MS has gained interest since these trials. Limited information is present on the effects of current immunomodulatory therapies on B cell functions, although effects of both first-line (interferon, glatiramer acetate, dimethyl fumarate and teriflunomide, second-line (fingolimod, natalizumab and even third-line (monoclonal antibody therapies treatments on B cell subtype distribution, expression of functional surface markers and secretion of different cytokines by B cells have been studied to some extent. In this review, we summarize the effects of different MS related treatments on B cell functions that have been described up to now in order to find new research opportunities and contribute to the understanding of the pathogenesis of MS.

  12. B cell activation by outer membrane vesicles--a novel virulence mechanism.

    Directory of Open Access Journals (Sweden)

    Maria Laura A Perez Vidakovics

    2010-01-01

    Full Text Available Secretion of outer membrane vesicles (OMV is an intriguing phenomenon of Gram-negative bacteria and has been suggested to play a role as virulence factors. The respiratory pathogens Moraxella catarrhalis reside in tonsils adjacent to B cells, and we have previously shown that M. catarrhalis induce a T cell independent B cell response by the immunoglobulin (Ig D-binding superantigen MID. Here we demonstrate that Moraxella are endocytosed and killed by human tonsillar B cells, whereas OMV have the potential to interact and activate B cells leading to bacterial rescue. The B cell response induced by OMV begins with IgD B cell receptor (BCR clustering and Ca(2+ mobilization followed by BCR internalization. In addition to IgD BCR, TLR9 and TLR2 were found to colocalize in lipid raft motifs after exposure to OMV. Two components of the OMV, i.e., MID and unmethylated CpG-DNA motifs, were found to be critical for B cell activation. OMV containing MID bound to and activated tonsillar CD19(+ IgD(+ lymphocytes resulting in IL-6 and IgM production in addition to increased surface marker density (HLA-DR, CD45, CD64, and CD86, whereas MID-deficient OMV failed to induce B cell activation. DNA associated with OMV induced full B cell activation by signaling through TLR9. Importantly, this concept was verified in vivo, as OMV equipped with MID and DNA were found in a 9-year old patient suffering from Moraxella sinusitis. In conclusion, Moraxella avoid direct interaction with host B cells by redirecting the adaptive humoral immune response using its superantigen-bearing OMV as decoys.

  13. Diagnostic value of immunoglobulin κ light chain gene rearrangement analysis in B-cell lymphomas.

    Science.gov (United States)

    Kokovic, Ira; Jezersek Novakovic, Barbara; Novakovic, Srdjan

    2015-03-01

    Analysis of the immunoglobulin κ light chain (IGK) gene is an alternative method for B-cell clonality assessment in the diagnosis of mature B-cell proliferations in which the detection of clonal immunoglobulin heavy chain (IGH) gene rearrangements fails. The aim of the present study was to evaluate the added value of standardized BIOMED-2 assay for the detection of clonal IGK gene rearrangements in the diagnostic setting of suspected B-cell lymphomas. With this purpose, 92 specimens from 80 patients with the final diagnosis of mature B-cell lymphoma (37 specimens), mature T-cell lymphoma (26 specimens) and reactive lymphoid proliferation (29 specimens) were analyzed for B-cell clonality. B-cell clonality analysis was performed using the BIOMED-2 IGH and IGK gene clonality assays. The determined sensitivity of the IGK assay was 67.6%, while the determined sensitivity of the IGH assay was 75.7%. The sensitivity of combined IGH+IGK assay was 81.1%. The determined specificity of the IGK assay was 96.2% in the group of T-cell lymphomas and 96.6% in the group of reactive lesions. The determined specificity of the IGH assay was 84.6% in the group of lymphomas and 86.2% in the group of reactive lesions. The comparison of GeneScan (GS) and heteroduplex pretreatment-polyacrylamide gel electrophoresis (HD-PAGE) methods for the analysis of IGK gene rearrangements showed a higher efficacy of GS analysis in a series of 27 B-cell lymphomas analyzed by both methods. In the present study, we demonstrated that by applying the combined IGH+IGK clonality assay the overall detection rate of B-cell clonality was increased by 5.4%. Thus, we confirmed the added value of the standardized BIOMED-2 IGK assay for assessment of B-cell clonality in suspected B-cell lymphomas with inconclusive clinical and cyto/histological diagnosis.

  14. B cells promote obesity-associated periodontitis and oral pathogen-associated inflammation.

    Science.gov (United States)

    Zhu, Min; Belkina, Anna C; DeFuria, Jason; Carr, Jordan D; Van Dyke, Thomas E; Gyurko, Robert; Nikolajczyk, Barbara S

    2014-08-01

    Individuals with T2D and PD suffer significantly from the ability of one disease to intensify the other. Disease-associated inflammation is one mechanism thought to fuel this pathogenic feed-forward loop. Several lines of evidence indicate that proinflammatory B cells promote T2D and PD; thus, B cells are top candidates for a cell type that predisposes PD in T2D. To test directly the role of B cells in T2D-associated PD, we compared outcomes from oral Porphyromonas gingivalis challenge of lean WT or B cell-null mice with outcomes from mice that were obese and insulin-resistant before challenge. Obese WT mice responded to oral P. gingivalis challenge with significant periodontal bone loss, whereas obese B cell-null mice were protected completely from PD. By contrast, lean WT and B cell-null mice suffer similar periodontal bone loss in response to oral pathogen. B cells from obese/insulin-resistant hosts also support oral osteoclastogenesis and both oral and systemic production of inflammatory cytokines, including pro-osteoclastogenic TNF-α and MIP-2, an ortholog of human IL-8. B cells furthermore impact AT inflammation in obese, P. gingivalis-infected hosts. Taken together, these data show that fundamentally different mechanisms regulate PD in lean and obese hosts, with B cells able to promote PD only if the hosts are "primed" by obesity. These results justify more intense analysis of obesity-associated changes in B cells that predispose PD in human T2D. © 2014 Society for Leukocyte Biology.

  15. Differential Effects of Tacrolimus versus Sirolimus on the Proliferation, Activation and Differentiation of Human B Cells.

    Directory of Open Access Journals (Sweden)

    Opas Traitanon

    Full Text Available The direct effect of immunosuppressive drugs calcineurin inhibitor (Tacrolimus, TAC and mTOR inhibitor (Sirolimus, SRL on B cell activation, differentiation and proliferation is not well documented. Purified human B cells from healthy volunteers were stimulated through the B Cell Receptor with Anti-IgM + anti-CD40 + IL21 in the absence / presence of TAC or SRL. A variety of parameters of B cell activity including activation, differentiation, cytokine productions and proliferation were monitored by flow cytometry. SRL at clinically relevant concentrations (6 ng/ml profoundly inhibited CD19(+ B cell proliferation compared to controls whereas TAC at similar concentrations had a minimal effect. CD27(+ memory B cells were affected more by SRL than naïve CD27- B cells. SRL effectively blocked B cell differentiation into plasma cells (CD19(+CD138(+ and Blimp1(+/Pax5(low cells even at low dose (2 ng/ml, and totally eliminated them at 6 ng/ml. SRL decreased absolute B cell counts, but the residual responding cells acquired an activated phenotype (CD25(+/CD69(+ and increased the expression of HLA-DR. SRL-treated stimulated B cells on a per cell basis were able to enhance the proliferation of allogeneic CD4(+CD25(- T cells and induce a shift toward the Th1 phenotype. Thus, SRL and TAC have different effects on B lymphocytes. These data may provide insights into the clinical use of these two agents in recipients of solid organ transplants.

  16. Intrinsic and extrinsic factors influencing the clinical course of B-cell chronic lymphocytic leukemia: prognostic markers with pathogenetic relevance

    Directory of Open Access Journals (Sweden)

    Gaidano Gianluca

    2009-08-01

    Full Text Available Abstract B-cell chronic lymphocytic leukemia (CLL, the most frequent leukemia in the Western world, is characterized by extremely variable clinical courses with survivals ranging from 1 to more than 15 years. The pathogenetic factors playing a key role in defining the biological features of CLL cells, hence eventually influencing the clinical aggressiveness of the disease, are here divided into "intrinsic factors", mainly genomic alterations of CLL cells, and "extrinsic factors", responsible for direct microenvironmental interactions of CLL cells; the latter group includes interactions of CLL cells occurring via the surface B cell receptor (BCR and dependent to specific molecular features of the BCR itself and/or to the presence of the BCR-associated molecule ZAP-70, or via other non-BCR-dependent interactions, e.g. specific receptor/ligand interactions, such as CD38/CD31 or CD49d/VCAM-1. A putative final model, discussing the pathogenesis and the clinicobiological features of CLL in relationship of these factors, is also provided.

  17. Molecule Matters

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 12. Molecule Matters - Dinitrogen. A G Samuelson J Jabadurai. Volume 16 Issue 12 ... Author Affiliations. A G Samuelson1 J Jabadurai1. Department of Inroganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India.

  18. Molecule Matters

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 9. Molecule Matters - A Chromium Compound with a Quintuple Bond. K C Kumara Swamy. Feature Article Volume 11 Issue 9 September 2006 pp 72-75. Fulltext. Click here to view fulltext PDF. Permanent link:

  19. Specific Antibody Production by Blood B Cells is Retained in Late Stage Drug-naïve HIV-infected Africans

    Directory of Open Access Journals (Sweden)

    Lydie Béniguel

    2004-01-01

    Full Text Available Unseparated peripheral blood mononuclear cells (PBMCs obtained from drug-naïve African individuals living in a context of multi-infections and presenting with high viral load (VL, were cultured in vitro and tested for their ability to produce antibodies (Abs reacting with HIV-1 antigens. Within these PBMCs, circulating B cells were differentiated in vitro and produced IgG Abs against not only ENV, but also GAG and POL proteins. Under similar experimental conditions, HAART treated patients produced Abs to ENV proteins only. The in vitro antibody production by drug-naïve individuals' PBMCs depended on exogenous cytokines (IL-2 and IL-10 but neither on the re-stimulation of reactive cells in cultures by purified HIV-1-gp 160 antigen nor on the re-engagement of CD40 surface molecules. Further, it was not abrogated by the addition of various monoclonal Abs (mAbs to co-stimulatory molecules. This suggests that the in vitro antibody production by drug-naïve individuals' PBMCs resulted from the maturation of already envelope and core antigen-primed, differentiated B cells, presumably pre-plasma cells, which are not known to circulate at homeostasy. As in vitro produced Abs retained the capacity of binding antigen and forming complexes, this study provides pre-clinical support for functional humoral responses despite major HIV- and other tropical pathogen-induced B cell perturbations.

  20. Regulatory activities

    International Nuclear Information System (INIS)

    2001-01-01

    This publication, compiled in 8 chapters, presents the regulatory system developed by the Nuclear Regulatory Authority (NRA) of the Argentine Republic. The following activities and developed topics in this document describe: the evolution of the nuclear regulatory activity in Argentina; the Argentine regulatory system; the nuclear regulatory laws and standards; the inspection and safeguards of nuclear facilities; the emergency systems; the environmental systems; the environmental monitoring; the analysis laboratories on physical and biological dosimetry, prenatal irradiation, internal irradiation, radiation measurements, detection techniques on nuclear testing, medical program on radiation protection; the institutional relations with national and international organization; the training courses and meeting; the technical information

  1. FOXP1 suppresses immune response signatures and MHC class II expression in activated B-cell-like diffuse large B-cell lymphomas

    DEFF Research Database (Denmark)

    Brown, P J; Wong, K K; Felce, S L

    2016-01-01

    The FOXP1 (forkhead box P1) transcription factor is a marker of poor prognosis in diffuse large B-cell lymphoma (DLBCL). Here microarray analysis of FOXP1-silenced DLBCL cell lines identified differential regulation of immune response signatures and major histocompatibility complex class II (MHC II......) genes as some of the most significant differences between germinal center B-cell (GCB)-like DLBCL with full-length FOXP1 protein expression versus activated B-cell (ABC)-like DLBCL expressing predominantly short FOXP1 isoforms. In an independent primary DLBCL microarray data set, multiple MHC II genes......, including human leukocyte antigen DR alpha chain (HLA-DRA), were inversely correlated with FOXP1 transcript expression (PABC-DLBCL cells led to increased cell-surface expression of HLA-DRA and CD74. In R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone...

  2. Maternal allergic disease does not affect the phenotype of T and B cells or the immune response to allergens in neonates.

    Science.gov (United States)

    Rindsjö, E; Joerink, M; Johansson, C; Bremme, K; Malmström, V; Scheynius, A

    2010-07-01

    It is hypothesized that the in utero environment in allergic mothers can affect the neonatal immune responses. The aim of this study was to analyse the effect of maternal allergic disease on cord blood mononuclear cell (CBMC) phenotype and proliferative responses upon allergen stimulation. Peripheral blood mononuclear cells (PBMC) from 12 allergic and 14 nonallergic mothers and CBMC from their children were analysed. In the mothers, we determined cell proliferation, production of IL-4 and expression of FOXP3 in response to allergen stimulation. In the children, we evaluated cell proliferation and FOXP3 expression following allergen stimulation. Furthermore, expression of different homing markers on T cells and regulatory T cells and maturity of the T cells and B cell subsets were evaluated directly ex vivo. The timothy- and birch-allergic mothers responded with increased proliferation and/or IL-4 production towards timothy and birch extract, respectively, when compared to nonallergic mothers. This could not be explained by impairment of FOXP3(+) regulatory T cells in the allergic mothers. CBMC proliferation and FOXP3 expression in response to allergens were not affected by the allergic status of the mother. Also, phenotype of T cells, FOXP3(+) regulatory T cells and B cells was not affected by the allergic status of the mother. Our results suggest that maternal allergic disease has no effect on the neonatal response to allergens or the phenotype of neonatal lymphocytes. The factors studied here could, however, still affect later development of allergy.

  3. Characterization of Antigen-Specific B Cells Using Nominal Antigen-Coated Flow-Beads

    Science.gov (United States)

    Akl, Ahmed; Lepetit, Maud; Crochette, Romain; Giral, Magali; Lepourry, Julie; Pallier, Annaick; Castagnet, Stéphanie; Dugast, Emilie; Guillot-Gueguen, Cécile; Jacq-Foucher, Marylène; Saulquin, Xavier; Cesbron, Anne; Laplaud, David; Nicot, Arnaud; Brouard, Sophie; Soulillou, Jean-Paul

    2013-01-01

    In order to characterize the reactivity of B cells against nominal antigens, a method based on the coupling of antigens onto the surface of fluorescent core polystyrene beads was developed. We first demonstrate that murine B cells with a human MOG-specific BCR are able to interact with MOG-coated beads and do not recognize beads coated with human albumin or pp65. B cells purified from human healthy volunteer blood or immunized individuals were tested for their ability to interact with various nominal antigens, including viral, vaccine, self and alloantigens, chosen for their usefulness in studying a variety of pathological processes. A substantial amount of B cells binding self-antigen MOG-coated beads can be detected in normal blood. Furthermore, greater frequencies of B cell against anti-Tetanic Toxin or anti-EBNA1 were observed in primed individuals. This method can reveal increased frequencies of anti-HLA committed B cells in patients with circulating anti-HLA antibodies compared to unsensitized patients and normal individuals. Of interest, those specific CD19 cells were preferentially identified within CD27−IgD+ (i-e naïve) subset. These observations suggest that a broad range of medical situations could benefit from a tool that allows the detection, the quantification and the characterization of antigen-specific blood B cells. PMID:24386360

  4. Analysis of antigen-specific B-cell memory directly ex vivo.

    Science.gov (United States)

    McHeyzer-Williams, Louise J; McHeyzer-Williams, Michael G

    2004-01-01

    Helper T-cell-regulated B-cell memory develops in response to initial antigen priming as a cellular product of the germinal center (GC) reaction. On antigen recall, memory response precursors expand rapidly with exaggerated differentiation into plasma cells to produce the high-titer, high-affinity antibody(Ab) that typifies the memory B-cell response in vivo. We have devised a high-resolution flow cytometric strategy to quantify the emergence and maintenance of antigen-specific memory B cells directly ex vivo. Extended cell surface phenotype establishes a level of cellular diversity not previously appreciated for the memory B-cell compartment. Using an "exclusion transfer" strategy, we ascertain the capacity of two distinct memory B-cell populations to transfer antigen-specific memory into naive adoptive hosts. Finally, we sequence expressed messenger ribonucleic acid (mRNA) from single cells within the population to estimate the level of somatic hypermutation as the best molecular indicator of B-cell memory. In this chapter, we describe the methods used in each of these four sections that serve to provide high-resolution quantification of antigen-specific B-cell memory responses directly ex vivo.

  5. An increase in circulating B cell-activating factor in childhood-onset ocular myasthenia gravis.

    Science.gov (United States)

    Motobayashi, Mitsuo; Inaba, Yuji; Nishimura, Takafumi; Kobayashi, Norimoto; Nakazawa, Yozo; Koike, Kenichi

    2015-04-01

    Myasthenia gravis is a B cell-mediated autoimmune disorder. The pathophysiology of childhood-onset ocular myasthenia gravis remains unclear. We investigated serum B cell-activating factor levels and other immunological parameters in child patients with ocular myasthenia gravis. Blood samples were obtained from 9 children with ocular myasthenia gravis and 20 age-matched controls. We assayed serum concentrations of B cell-activating factor, anti-acetylcholine receptor antibody titers, 7 types of cytokines (interleukins-2, -4, -6, -10, and -17A; interferon-γ; tumor necrosis factor-α) as well as the percentages of peripheral blood CD4+, CD8+, and CD19+ cells. Serum B cell-activating factor levels were significantly higher before immunosuppressive therapy in patients with childhood-onset ocular myasthenia gravis than in controls and decreased after immunosuppressive therapy. A significant positive correlation was observed between serum B cell-activating factor levels and anti-acetylcholine receptor antibody titers in patients with myasthenia gravis. Serum B cell-activating factor concentrations did not correlate with the percentages of CD4+, CD8+, and CD19+ cells or the CD4+/CD8+ ratio. No significant differences were observed in the levels of the 7 different types of cytokines examined, including interleukin-17A, between preimmunosuppressive therapy myasthenia gravis patients and controls. Circulating B cell-activating factor may play a key role in the pathophysiology of childhood-onset ocular myasthenia gravis. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Most B cells in non-lymphoid tissues are naïve.

    Science.gov (United States)

    Inman, Charlotte F; Murray, Tamsin Zangerle; Bailey, Mick; Cose, Stephen

    2012-02-01

    The current view of lymphocyte migration states that naïve lymphocytes re-circulate between the blood and the lymph via the lymph nodes, but are not able to access non-lymphoid tissues. We examined B lymphocytes in peripheral tissues and found that the majority were phenotypically similar to naïve B cells in lymphoid tissues and were located within the parenchyma, not associated with blood vessels. The mutation rate within the Vh region of these cells was substantially less than the rate attributed to somatic hypermutation and was identical to that observed in naïve B cells isolated from the lymph nodes, showing the presence of naïve B cells in the non-lymphoid organs. Further, using FTY720-treated mice, we showed that naïve B cells migrate through the peripheral tissues and, using pertussis toxin, that the entry of B cells was not controlled by chemokine-mediated signalling events. Overall, these results show that naïve B lymphocytes constitute the majority of the total B-cell population in non-lymphoid tissues and suggest that these cells may re-circulate through the periphery as part of their normal migration pathway. This has implications for the current view of the role of naïve B cells in priming and tolerance.

  7. The impact of inflammation and immune activation on B cell differentiation during HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Nicolas eRuffin

    2012-01-01

    Full Text Available HIV-1 infection is characterized by continuous antigenic stimulation, chronic immune activation and impaired survival of T and B cells. A decline of resting memory B cells has previously been reported to occur in both children and adults infected with HIV-1; these cells are responsible for mounting and maintaining an adequate serological response to antigens previously encountered in life through natural infection or vaccination. Further understanding of the mechanisms leading to impaired B cell differentiation and germinal center reaction might be essential to design new HIV vaccines and therapies that could improve humoral immune responses in HIV-1 infected individuals. In the present article we summarize the literature and present our view on critical mechanisms of B cell development which are impaired during HIV-1 infection. We also discuss the impact of microbial translocation, a driving force for persistent inflammation during HIV-1 infection, on survival of terminally differentiated B cells and how the altered expression of cytokines/chemokines pivotal for communication between T and B cells in lymphoid tissues may impair formation of memory B cells.

  8. Morphologic and Functional Effects of Gamma Secretase Inhibition on Splenic Marginal Zone B Cells

    Directory of Open Access Journals (Sweden)

    Maria Cristina de Vera Mudry

    2012-01-01

    Full Text Available The γ-secretase complex is a promising target in Alzheimer’s disease because of its role in the amyloidogenic processing of β-amyloid precursor protein. This enzyme also catalyzes the cleavage of Notch receptor, resulting in the nuclear translocation of intracellular Notch where it modulates gene transcription. Notch signaling is essential in cell fate decisions during embryogenesis, neuronal differentiation, hematopoiesis, and development of T and B cells, including splenic marginal zone (MZ B cells. This B cell compartment participates in the early phases of the immune response to blood-borne bacteria and viruses. Chronic treatment with the oral γ-secretase inhibitor RO4929097 resulted in dose-dependent decreased cellularity (atrophy of the MZ of rats and mice. Significant decreases in relative MZ B-cell numbers of RO4929097-treated animals were confirmed by flow cytometry. Numbers of MZ B cells reverted to normal after a sufficient RO4929097-free recovery period. Functional characterization of the immune response in relation to RO4929097-related MZ B cell decrease was assessed in mice vaccinated with inactivated vesicular stomatitis virus (VSV. Compared with the immunosuppressant cyclosporin A, RO4929097 caused only mild and reversible delayed early neutralizing IgM and IgG responses to VSV. Thus, the functional consequence of MZ B cell decrease on host defense is comparatively mild.

  9. Morphologic and Functional Effects of Gamma Secretase Inhibition on Splenic Marginal Zone B Cells

    Science.gov (United States)

    de Vera Mudry, Maria Cristina; Regenass-Lechner, Franziska; Ozmen, Laurence; Altmann, Bernd; Festag, Matthias; Singer, Thomas; Müller, Lutz; Jacobsen, Helmut; Flohr, Alexander

    2012-01-01

    The γ-secretase complex is a promising target in Alzheimer's disease because of its role in the amyloidogenic processing of β-amyloid precursor protein. This enzyme also catalyzes the cleavage of Notch receptor, resulting in the nuclear translocation of intracellular Notch where it modulates gene transcription. Notch signaling is essential in cell fate decisions during embryogenesis, neuronal differentiation, hematopoiesis, and development of T and B cells, including splenic marginal zone (MZ) B cells. This B cell compartment participates in the early phases of the immune response to blood-borne bacteria and viruses. Chronic treatment with the oral γ-secretase inhibitor RO4929097 resulted in dose-dependent decreased cellularity (atrophy) of the MZ of rats and mice. Significant decreases in relative MZ B-cell numbers of RO4929097-treated animals were confirmed by flow cytometry. Numbers of MZ B cells reverted to normal after a sufficient RO4929097-free recovery period. Functional characterization of the immune response in relation to RO4929097-related MZ B cell decrease was assessed in mice vaccinated with inactivated vesicular stomatitis virus (VSV). Compared with the immunosuppressant cyclosporin A, RO4929097 caused only mild and reversible delayed early neutralizing IgM and IgG responses to VSV. Thus, the functional consequence of MZ B cell decrease on host defense is comparatively mild. PMID:23316412

  10. Cyclosporine A suppresses immunoglobulin G biosynthesis via inhibition of cyclophilin B in murine hybridomas and B cells.

    Science.gov (United States)

    Lee, Jisun; Choi, Tae Gyu; Ha, Joohun; Kim, Sung Soo

    2012-01-01

    Immunoglubulin G (IgG) is a major isotype of antibody, which is predominantly involved in immune response. The complete tetramer is needed to fold and assemble in endoplasmic reticulum (ER) prior to secretion from cells. Protein quality control guided by ER chaperons is most essential for full biological activity. Cyclophilin B (CypB) was initially identified as a high-affinity binding protein for the immunosuppressive drug Cyclosporine A (CsA). CsA suppresses organ rejection by halting productions of pro-inflammatory molecules in T cell and abolishes the enzymatic property of CypB that accelerates the folding of proteins by catalysing the isomerization of peptidyl-proline bonds in ER. Here, we reported that CsA significantly inhibited IgG biosynthesis at posttranslational level in antibody secreting cells. Moreover, CsA stimulated the extracellular secretion of CypB and induced ROS generation, leading to expressions of ER stress markers. In addition, the absence of intracellular CypB impaired the formation of ER multiprotein complex, which is most important for resisting ER stress. Interestingly, CsA interrupted IgG folding via occupying the PPIase domain of CypB in ER. Eventually, unfolded IgG is degraded via Herp-dependent ERAD pathway. Furthermore, IgG biosynthesis was really abrogated by inhibition of CypB in primary B cells. We established for the first time the immunosuppressive effect of CsA on B cells. Conclusively, the combined results of the current study suggest that CypB is a pivotal molecule for IgG biosynthesis in ER quality control. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Rgs13 constrains early B cell responses and limits germinal center sizes.

    Directory of Open Access Journals (Sweden)

    Il-Young Hwang

    Full Text Available Germinal centers (GCs are microanatomic structures that develop in secondary lymphoid organs in response to antigenic stimulation. Within GCs B cells clonally expand and their immunoglobulin genes undergo class switch recombination and somatic hypermutation. Transcriptional profiling has identified a number of genes that are prominently expressed in GC B cells. Among them is Rgs13, which encodes an RGS protein with a dual function. Its canonical function is to accelerate the intrinsic GTPase activity of heterotrimeric G-protein α subunits at the plasma membrane, thereby limiting heterotrimeric G-protein signaling. A unique, non-canonical function of RGS13 occurs following translocation to the nucleus, where it represses CREB transcriptional activity. The functional role of RGS13 in GC B cells is unknown. To create a surrogate marker for Rgs13 expression and a loss of function mutation, we inserted a GFP coding region into the Rgs13 genomic locus. Following immunization GFP expression rapidly increased in activated B cells, persisted in GC B cells, but declined in newly generated memory B and plasma cells. Intravital microscopy of the inguinal lymph node (LN of immunized mice revealed the rapid appearance of GFP(+ cells at LN interfollicular regions and along the T/B cell borders, and eventually within GCs. Analysis of WT, knock-in, and mixed chimeric mice indicated that RGS13 constrains extra-follicular plasma cell generation, GC size, and GC B cell numbers. Analysis of select cell cycle and GC specific genes disclosed an aberrant gene expression profile in the Rgs13 deficient GC B cells. These results indicate that RGS13, likely acting at cell membranes and in nuclei, helps coordinate key decision points during the expansion and differentiation of naive B cells.

  12. Rgs13 constrains early B cell responses and limits germinal center sizes.

    Science.gov (United States)

    Hwang, Il-Young; Hwang, Kyung-Sun; Park, Chung; Harrison, Kathleen A; Kehrl, John H

    2013-01-01

    Germinal centers (GCs) are microanatomic structures that develop in secondary lymphoid organs in response to antigenic stimulation. Within GCs B cells clonally expand and their immunoglobulin genes undergo class switch recombination and somatic hypermutation. Transcriptional profiling has identified a number of genes that are prominently expressed in GC B cells. Among them is Rgs13, which encodes an RGS protein with a dual function. Its canonical function is to accelerate the intrinsic GTPase activity of heterotrimeric G-protein α subunits at the plasma membrane, thereby limiting heterotrimeric G-protein signaling. A unique, non-canonical function of RGS13 occurs following translocation to the nucleus, where it represses CREB transcriptional activity. The functional role of RGS13 in GC B cells is unknown. To create a surrogate marker for Rgs13 expression and a loss of function mutation, we inserted a GFP coding region into the Rgs13 genomic locus. Following immunization GFP expression rapidly increased in activated B cells, persisted in GC B cells, but declined in newly generated memory B and plasma cells. Intravital microscopy of the inguinal lymph node (LN) of immunized mice revealed the rapid appearance of GFP(+) cells at LN interfollicular regions and along the T/B cell borders, and eventually within GCs. Analysis of WT, knock-in, and mixed chimeric mice indicated that RGS13 constrains extra-follicular plasma cell generation, GC size, and GC B cell numbers. Analysis of select cell cycle and GC specific genes disclosed an aberrant gene expression profile in the Rgs13 deficient GC B cells. These results indicate that RGS13, likely acting at cell membranes and in nuclei, helps coordinate key decision points during the expansion and differentiation of naive B cells.

  13. Farnesyl transferase inhibitors induce extended remissions in transgenic mice with mature B cell lymphomas

    Directory of Open Access Journals (Sweden)

    Refaeli Yosef

    2008-05-01

    Full Text Available Abstract Background We have used a mouse model based on overexpression of c-Myc in B cells genetically engineered to be self-reactive to test the hypothesis that farnesyl transferase inhibitors (FTIs can effectively treat mature B cell lymphomas. FTIs are undergoing clinical trials to treat both lymphoid and non-lymphoid malignancies and we wished to obtain evidence to support the inclusion of B cell lymphomas in future trials. Results We report that two FTIs, L-744,832 and SCH66336, blocked the growth of mature B cell lymphoma cells in vitro and in vivo. The FTI treatment affected the proliferation and survival of the transformed B cells to a greater extent than naïve B cells stimulated with antigen. In syngeneic mice transplanted with the transgenic lymphoma cells, L-744,832 treatment prevented the growth of the tumor cells and the morbidity associated with the resulting lymphoma progression. Tumors that arose from transplantation of the lymphoma cells regressed with as little as three days of treatment with L-744,832 or SCH66336. Treatment of these established lymphomas with L-744,832 for seven days led to long-term remission of the disease in approximately 25% of animals. Conclusion FTI treatment can block the proliferation and survival of self-reactive transformed B cells that overexpress Myc. In mice transplanted with mature B cell lymphomas, we found that FTI treatment led to regression of disease. FTIs warrant further consideration as therapeutic agents for mature B cell lymphomas and other lymphoid tumors.

  14. To B or not to B cells-mediate a healthy start to life.

    Science.gov (United States)

    Nguyen, T G; Ward, C M; Morris, J M

    2013-02-01

    Maternal immune responses during pregnancy are critical in programming the future health of a newborn. The maternal immune system is required to accommodate fetal immune tolerance as well as to provide a protective defence against infections for the immunocompromised mother and her baby during gestation and lactation. Natural immunity and antibody production by maternal B cells play a significant role in providing such immunoprotection. However, aberrations in the B cell compartment as a consequence of maternal autoimmunity can pose serious risks to both the mother and her baby. Despite their potential implication in shaping pregnancy outcomes, the role of B cells in human pregnancy has been poorly studied. This review focuses on the role of B cells and the implications of B cell depletion therapy in pregnancy. It highlights the evidence of an association between aberrant B cell compartment and obstetric conditions. It also alludes to the potential mechanisms that amplify these B cell aberrances and thereby contribute to exacerbation of some maternal autoimmune conditions and poor neonatal outcomes. Clinical and experimental evidence suggests strongly that maternal autoantibodies contribute directly to the pathologies of obstetric and neonatal conditions that have significant implications for the lifelong health of a newborn. The evidence for clinical benefit and safety of B cell depletion therapies in pregnancy is reviewed, and an argument is mounted for further clinical evaluation of B cell-targeted therapies in high-risk pregnancy, with an emphasis on improving neonatal outcomes and prevention of neonatal conditions such as congenital heart block and fetal/neonatal alloimmune thrombocytopenia. © 2012 British Society for Immunology.

  15. N-wasp is essential for the negative regulation of B cell receptor signaling.

    Directory of Open Access Journals (Sweden)

    Chaohong Liu

    2013-11-01

    Full Text Available Negative regulation of receptor signaling is essential for controlling cell activation and differentiation. In B-lymphocytes, the down-regulation of B-cell antigen receptor (BCR signaling is critical for suppressing the activation of self-reactive B cells; however, the mechanism underlying the negative regulation of signaling remains elusive. Using genetically manipulated mouse models and total internal reflection fluorescence microscopy, we demonstrate that neuronal Wiskott-Aldrich syndrome protein (N-WASP, which is coexpressed with WASP in all immune cells, is a critical negative regulator of B-cell signaling. B-cell-specific N-WASP gene deletion causes enhanced and prolonged BCR signaling and elevated levels of autoantibodies in the mouse serum. The increased signaling in N-WASP knockout B cells is concurrent with increased accumulation of F-actin at the B-cell surface, enhanced B-cell spreading on the antigen-presenting membrane, delayed B-cell contraction, inhibition in the merger of signaling active BCR microclusters into signaling inactive central clusters, and a blockage of BCR internalization. Upon BCR activation, WASP is activated first, followed by N-WASP in mouse and human primary B cells. The activation of N-WASP is suppressed by Bruton's tyrosine kinase-induced WASP activation, and is restored by the activation of SH2 domain-containing inositol 5-phosphatase that inhibits WASP activation. Our results reveal a new mechanism for the negative regulation of BCR signaling and broadly suggest an actin-mediated mechanism for signaling down-regulation.

  16. Obligatory Role for B Cells in the Development of Angiotensin II-Dependent Hypertension.

    Science.gov (United States)

    Chan, Christopher T; Sobey, Christopher G; Lieu, Maggie; Ferens, Dorota; Kett, Michelle M; Diep, Henry; Kim, Hyun Ah; Krishnan, Shalini M; Lewis, Caitlin V; Salimova, Ekaterina; Tipping, Peter; Vinh, Antony; Samuel, Chrishan S; Peter, Karlheinz; Guzik, Tomasz J; Kyaw, Tin S; Toh, Ban-Hock; Bobik, Alexander; Drummond, Grant R

    2015-11-01

    Clinical hypertension is associated with raised serum IgG antibodies. However, whether antibodies are causative agents in hypertension remains unknown. We investigated whether hypertension in mice is associated with B-cell activation and IgG production and moreover whether B-cell/IgG deficiency affords protection against hypertension and vascular remodeling. Angiotensin II (Ang II) infusion (0.7 mg/kg per day; 28 days) was associated with (1) a 25% increase in the proportion of splenic B cells expressing the activation marker CD86, (2) an 80% increase in splenic plasma cell numbers, (3) a 500% increase in circulating IgG, and (4) marked IgG accumulation in the aortic adventitia. In B-cell-activating factor receptor-deficient (BAFF-R(-/-)) mice, which lack mature B cells, there was no evidence of Ang II-induced increases in serum IgG. Furthermore, the hypertensive response to Ang II was attenuated in BAFF-R(-/-) (Δ30±4 mm Hg) relative to wild-type (Δ41±5 mm Hg) mice, and this response was rescued by B-cell transfer. BAFF-R(-/-) mice displayed reduced IgG accumulation in the aorta, which was associated with 80% fewer aortic macrophages and a 70% reduction in transforming growth factor-β expression. BAFF-R(-/-) mice were also protected from Ang II-induced collagen deposition and aortic stiffening (assessed by pulse wave velocity analysis). Finally, like BAFF-R deficiency, pharmacological depletion of B cells with an anti-CD20 antibody attenuated Ang II-induced hypertension by ≈35%. Hence, these studies demonstrate that B cells/IgGs are crucial for the development of Ang II-induced hypertension and vessel remodeling in mice. Thus, B-cell-targeted therapies-currently used for autoimmune diseases-may hold promise as future treatments for hypertension. © 2015 American Heart Association, Inc.

  17. Low GILT expression is associated with poor patient survival in diffuse large B-cell lymphoma

    Directory of Open Access Journals (Sweden)

    Hannah ePhipps-Yonas

    2013-12-01

    Full Text Available The MHC class II-restricted antigen processing pathway presents antigenic peptides acquired in the endocytic route for the activation of CD4+ T cells. Multiple cancers express MHC class II, which may influence the anti-tumor immune response and patient outcome. Low MHC class II expression is associated with poor survival in diffuse large B-cell lymphoma (DLBCL, the most common form of aggressive non-Hodgkin lymphoma. Therefore, we investigated whether gamma-interferon-inducible lysosomal thiol reductase (GILT, an upstream component of the MHC class II-restricted antigen processing pathway that is not regulated by the transcription factor class II transactivator, may be important in DLBCL biology. GILT reduces protein disulfide bonds in the endocytic compartment, exposing additional epitopes for MHC class II binding and facilitating antigen presentation. In each of four independent gene expression profiling cohorts with a total of 585 DLBCL patients, low GILT expression was significantly associated with poor overall survival. In contrast, low expression of a classical MHC class II gene, HLA-DRA, was associated with poor survival in one of four cohorts. The association of low GILT expression with poor survival was independent of established clinical and molecular prognostic factors, the International Prognostic Index and the cell of origin classification, respectively. Immunohistochemical analysis of GILT expression in 96 DLBCL cases demonstrated variation in GILT protein expression within tumor cells which correlated strongly with GILT mRNA expression. These studies identify a novel association between GILT expression and clinical outcome in lymphoma. Our findings underscore the role of antigen processing in DLBCL and suggest that molecules targeting this pathway warrant investigation as potential therapeutics.

  18. Affinity maturation in an HIV broadly neutralizing B-cell lineage through reorientation of variable domains.

    Science.gov (United States)

    Fera, Daniela; Schmidt, Aaron G; Haynes, Barton F; Gao, Feng; Liao, Hua-Xin; Kepler, Thomas B; Harrison, Stephen C

    2014-07-15

    Rapidly evolving pathogens, such as human immunodeficiency and influenza viruses, escape immune defenses provided by most vaccine-induced antibodies. Proposed strategies to elicit broadly neutralizing antibodies require a deeper understanding of antibody affinity maturation and evolution of the immune response to vaccination or infection. In HIV-infected individuals, viruses and B cells evolve together, creating a virus-antibody "arms race." Analysis of samples from an individual designated CH505 has illustrated the interplay between an antibody lineage, CH103, and autologous viruses at various time points. The CH103 antibodies, relatively broad in their neutralization spectrum, interact with the CD4 binding site of gp120, with a contact dominated by CDRH3. We show by analyzing structures of progenitor and intermediate antibodies and by correlating them with measurements of binding to various gp120s that there was a shift in the relative orientation of the light- and heavy-chain variable domains during evolution of the CH103 lineage. We further show that mutations leading to this conformational shift probably occurred in response to insertions in variable loop 5 (V5) of the HIV envelope. The shift displaced the tips of the light chain away from contact with V5, making room for the inserted residues, which had allowed escape from neutralization by the progenitor antibody. These results, which document the selective mechanism underlying this example of a virus-antibody arms race, illustrate the functional significance of affinity maturation by mutation outside the complementarity determining region surface of the antibody molecule.

  19. Pathophysiology of B-cell intrinsic immunoglobulin class switch recombination deficiencies.

    Science.gov (United States)

    Durandy, Anne; Taubenheim, Nadine; Peron, Sophie; Fischer, Alain

    2007-01-01

    B-cell intrinsic immunoglobulin class switch recombination (Ig-CSR) deficiencies, previously termed hyper-IgM syndromes, are genetically determined conditions characterized by normal or elevated serum IgM levels and an absence or very low levels of IgG, IgA, and IgE. As a function of the molecular mechanism, the defective CSR is variably associated to a defect in the generation of somatic hypermutations (SHMs) in the Ig variable region. The study of Ig-CSR deficiencies contributed to a better delineation of the mechanisms underlying CSR and SHM, the major events of antigen-triggered antibody maturation. Four Ig-CSR deficiency phenotypes have been so far reported: the description of the activation-induced cytidine deaminase (AID) deficiency (Ig-CSR deficiency 1), caused by recessive mutations of AICDA gene, characterized by a defect in CSR and SHM, clearly established the role of AID in the induction of the Ig gene rearrangements underlying CSR and SHM. A CSR-specific function of AID has, however, been detected by the observation of a selective CSR defect caused by mutations affecting the C-terminus of AID. Ig-CSR deficiency 2 is the consequence of uracil-N-glycosylase (UNG) deficiency. Because UNG, a molecule of the base excision repair machinery, removes uracils from DNA and AID deaminates cytosines into uracils, that observation indicates that the AID-UNG pathway directly targets DNA of switch regions from the Ig heavy-chain locus to induce the CSR process. Ig-CSR deficiencies 3 and 4 are characterized by a selective CSR defect resulting from blocks at distinct steps of CSR. A further understanding of the CSR machinery is expected from their molecular definition.

  20. Multivalent Soluble Antigen Arrays Exhibit High Avidity Binding and Modulation of B Cell Receptor-Mediated Signaling to Drive Efficacy against Experimental Autoimmune Encephalomyelitis.

    Science.gov (United States)

    Hartwell, Brittany L; Pickens, Chad J; Leon, Martin; Berkland, Cory

    2017-06-12

    A pressing need exists for antigen-specific immunotherapies (ASIT) that induce selective tolerance in autoimmune disease while avoiding deleterious global immunosuppression. Multivalent soluble antigen arrays (SAgA PLP:LABL ), consisting of a hyaluronic acid (HA) linear polymer backbone cografted with multiple copies of autoantigen (PLP) and cell adhesion inhibitor (LABL) peptides, are designed to induce tolerance to a specific multiple sclerosis (MS) autoantigen. Previous studies established that hydrolyzable SAgA PLP:LABL , employing a degradable linker to codeliver PLP and LABL, was therapeutic in experimental autoimmune encephalomyelitis (EAE) in vivo and exhibited antigen-specific binding with B cells, targeted the B cell receptor (BCR), and dampened BCR-mediated signaling in vitro. Our results pointed to sustained BCR engagement as the SAgA PLP:LABL therapeutic mechanism, so we developed a new version of the SAgA molecule using nonhydrolyzable conjugation chemistry, hypothesizing it would enhance and maintain the molecule's action at the cell surface to improve efficacy. "Click SAgA" (cSAgA PLP:LABL ) uses hydrolytically stable covalent conjugation chemistry (Copper-catalyzed Azide-Alkyne Cycloaddition (CuAAC)) rather than a hydrolyzable oxime bond to attach PLP and LABL to HA. We explored cSAgA PLP:LABL B cell engagement and modulation of BCR-mediated signaling in vitro through flow cytometry binding and calcium flux signaling assays. Indeed, cSAgA PLP:LABL exhibited higher avidity B cell binding and greater dampening of BCR-mediated signaling than hydrolyzable SAgA PLP:LABL . Furthermore, cSAgA PLP:LABL exhibited significantly enhanced in vivo efficacy compared to hydrolyzable SAgA PLP:LABL , achieving equivalent efficacy at one-quarter of the dose. These results indicate that nonhydrolyzable conjugation increased the avidity of cSAgA PLP:LABL to drive in vivo efficacy through modulated BCR-mediated signaling.

  1. Deferoxamine compensates for decreases in B cell counts and reduces mortality in enterovirus 71-infected mice.

    Science.gov (United States)

    Yang, Yajun; Ma, Jing; Xiu, Jinghui; Bai, Lin; Guan, Feifei; Zhang, Li; Liu, Jiangning; Zhang, Lianfeng

    2014-07-07

    Enterovirus 71 is one of the major causative agents of hand, foot and mouth disease in children under six years of age. No vaccine or antiviral therapy is currently available. In this work, we found that the number of B cells was reduced in enterovirus 71-infected mice. Deferoxamine, a marine microbial natural product, compensated for the decreased levels of B cells caused by enterovirus 71 infection. The neutralizing antibody titer was also improved after deferoxamine treatment. Furthermore, deferoxamine relieved symptoms and reduced mortality and muscle damage caused by enterovirus 71 infection. This work suggested that deferoxamine has the potential for further development as a B cell-immunomodulator against enterovirus 71.

  2. ICAM-1-based rabies virus vaccine shows increased infection and activation of primary murine B cells in vitro and enhanced antibody titers in-vivo.

    Directory of Open Access Journals (Sweden)

    James E Norton

    Full Text Available We have previously shown that live-attenuated rabies virus (RABV-based vaccines infect and directly activate murine and human primary B cells in-vitro, which we propose can be exploited to help develop a single-dose RABV-based vaccine. Here we report on a novel approach to utilize the binding of Intracellular Adhesion Molecule-1 (ICAM-1 to its binding partner, Lymphocyte Function-associated Antigen-1 (LFA-1, on B cells to enhance B cell activation and RABV-specific antibody responses. We used a reverse genetics approach to clone, recover, and characterize a live-attenuated recombinant RABV-based vaccine expressing the murine Icam1 gene (rRABV-mICAM-1. We show that the murine ICAM-1 gene product is incorporated into virus particles, potentially exposing ICAM-1 to extracellular binding partners. While rRABV-mICAM-1 showed 10-100-fold decrease in viral titers on baby hamster kidney cells compared to the parental virus (rRABV, rRABV-mICAM-1 infected and activated primary murine B cells in-vitro more efficiently than rRABV, as indicated by significant upregulation of CD69, CD40, and MHCII on the surface of infected B cells. ICAM-1 expression on the virus surface was responsible for enhanced B cell infection since pre-treating rRABV-mICAM-1 with a neutralizing anti-ICAM-1 antibody reduced B cell infection to levels observed with rRABV alone. Furthermore, 100-fold less rRABV-mICAM-1 was needed to induce antibody titers in immunized mice equivalent to antibody titers observed in rRABV-immunized mice. Of note, only 10(3 focus forming units (ffu/mouse of rRABV-mICAM-1 was needed to induce significant anti-RABV antibody titers as early as five days post-immunization. As both speed and potency of antibody responses are important in controlling human RABV infection in a post-exposure setting, these data show that expression of Icam1 from the RABV genome, which is then incorporated into the virus particle, is a promising strategy for the development of a

  3. Retinoic Acid Signaling in B Cells Is Required for the Generation of an Effective T-Independent Immune Response.

    Science.gov (United States)

    Marks, Ellen; Ortiz, Carla; Pantazi, Eirini; Bailey, Charlotte S; Lord, Graham M; Waldschmidt, Thomas J; Noelle, Randolph J; Elgueta, Raul

    2016-01-01

    Retinoic acid (RA) plays an important role in the balance of inflammation and tolerance in T cells. Furthermore, it has been demonstrated that RA facilitates IgA isotype switching in B cells in vivo . However, it is unclear whether RA has a direct effect on T-independent B cell responses in vivo . To address this question, we generated a mouse model where RA signaling is specifically silenced in the B cell lineage. This was achieved through the overexpression of a dominant negative receptor α for RA (dnRARα) in the B cell lineage. In this model, we found a dramatic reduction in marginal zone (MZ) B cells and accumulation of transitional 2 B cells in the spleen. We also observed a reduction in B1 B cells in the peritoneum with a defect in the T-independent B cell response against 2,4,6-trinitrophenyl. This was not a result of inhibited development of B cells in the bone marrow, but likely the result of both defective expression of S1P 1 in MZ B cells and a defect in the development of MZ and B1 B cells. This suggests that RARα expression in B cells is important for B cell frequency in the MZ and peritoneum, which is crucial for the generation of T-independent humoral responses.

  4. Retinoic Acid Signaling in B Cells Is Required for the Generation of an Effective T-Independent Immune Response

    Science.gov (United States)

    Marks, Ellen; Ortiz, Carla; Pantazi, Eirini; Bailey, Charlotte S.; Lord, Graham M.; Waldschmidt, Thomas J.; Noelle, Randolph J.; Elgueta, Raul

    2016-01-01

    Retinoic acid (RA) plays an important role in the balance of inflammation and tolerance in T cells. Furthermore, it has been demonstrated that RA facilitates IgA isotype switching in B cells in vivo. However, it is unclear whether RA has a direct effect on T-independent B cell responses in vivo. To address this question, we generated a mouse model where RA signaling is specifically silenced in the B cell lineage. This was achieved through the overexpression of a dominant negative receptor α for RA (dnRARα) in the B cell lineage. In this model, we found a dramatic reduction in marginal zone (MZ) B cells and accumulation of transitional 2 B cells in the spleen. We also observed a reduction in B1 B cells in the peritoneum with a defect in the T-independent B cell response against 2,4,6-trinitrophenyl. This was not a result of inhibited development of B cells in the bone marrow, but likely the result of both defective expression of S1P1 in MZ B cells and a defect in the development of MZ and B1 B cells. This suggests that RARα expression in B cells is important for B cell frequency in the MZ and peritoneum, which is crucial for the generation of T-independent humoral responses. PMID:28066447

  5. Coordinate viral induction of tumor necrosis factor α and interferon β in human B cells and monocytes

    International Nuclear Information System (INIS)

    Goldfeld, A.E.; Maniatis, T.

    1989-01-01

    Human tumor necrosis factor α (TNF-α) gene expression can be induced primarily in cells of the monocyte/macrophage lineage by a variety of inducers, including lipopolysaccharide, phorbol esters such as phorbol 12-myristate 13-acetate, and virus or synthetic double-stranded RNA [poly(I)·poly(C)]. In this paper the authors show that the TNF-α gene also responds to virus and phorbol 12-myristate 13-acetate in B lymphocytes and that virus is the most potent inducer of TNF-α mRNA in both monocyte and B-cell lines. In addition, they show that viral infection coinduces the expression of TNF-α and interferon β mRNA and that viral induction of both genes is blocked by the kinase inhibitor 2-aminopurine. Inhibition of protein synthesis with cycloheximide had no effect on mRNA expression of the genes in one of three cell lines tested (U937) but blocked the viral induction of both genes in another (Namalwa). Thus, the regulatory factors required for mRNA induction of both genes are present prior to the addition of virus in U937 but not in Namalwa cells. However, in a third cell line (JY), cycloheximide blocked viral induction of the interferon β gene but not the TNF-α gene. Taken together, these observations suggest that viral induction of TNF-α and interferon β gene expression may involve overlapping pathways with both common and distinct regulatory factors

  6. B-cell-intrinsic hepatitis C virus expression leads to B-cell-lymphomagenesis and induction of NF-κB signalling.

    Directory of Open Access Journals (Sweden)

    Yuri Kasama

    Full Text Available Hepatitis C virus (HCV infection leads to the development of hepatic diseases, as well as extrahepatic disorders such as B-cell non-Hodgkin's lymphoma (B-NHL. To reveal the molecular signalling pathways responsible for HCV-associated B-NHL development, we utilised transgenic (Tg mice that express the full-length HCV genome specifically in B cells and develop non-Hodgkin type B-cell lymphomas (BCLs. The gene expression profiles in B cells from BCL-developing HCV-Tg mice, from BCL-non-developing HCV-Tg mice, and from BCL-non-developing HCV-negative mice were analysed by genome-wide microarray. In BCLs from HCV-Tg mice, the expression of various genes was modified, and for some genes, expression was influenced by the gender of the animals. Markedly modified genes such as Fos, C3, LTβR, A20, NF-κB and miR-26b in BCLs were further characterised using specific assays. We propose that activation of both canonical and alternative NF-κB signalling pathways and down-regulation of miR-26b contribute to the development of HCV-associated B-NHL.

  7. No Evidence for JAK2(V617F) Mutation in Monoclonal B Cells in 2 Patients with Polycythaemia Vera and Concurrent Monoclonal B Cell Disorder

    NARCIS (Netherlands)

    Stijnis, C.; Kroes, W. G. M.; Balkassmi, S.; Marijt, E. W. A.; van Rossum, A. P.; Bakker, E.; Vlasveld, L. T.

    2012-01-01

    Occurrence of Philadelphia chromosome-negative myeloproliferative neoplasms (Ph- MPN) and lymphoproliferative disorders, like B cell chronic lymphocytic leukaemia (B-CLL), in the same patient is rare. JAK2(V617F) mutation was recently introduced as a powerful diagnostic tool for Ph- MPN. JAK2(V617F)

  8. Hematopoietic cell phosphatase is recruited to CD22 following B cell antigen receptor ligation

    NARCIS (Netherlands)

    Lankester, A. C.; van Schijndel, G. M.; van Lier, R. A.

    1995-01-01

    Hematopoietic cell phosphatase is a nonreceptor protein tyrosine phosphatase that is preferentially expressed in hematopoietic cell lineages. Motheaten mice, which are devoid of (functional) hematopoietic cell phosphatase, have severe disturbances in the regulation of B cell activation and

  9. Importance of gallium-67 scintigraphy in primary cutaneous B-cell lymphoma: report of two cases

    International Nuclear Information System (INIS)

    Attab, Cyomara Sanches; Moriguchi, Sonia Marta; Rocha, Euclides Timoteo da

    2010-01-01

    The authors describe two cases of cutaneous B-cell lymphoma where correct staging, treatment and follow-up could be achieved through a combination of conventional imaging studies and gallium-67 scintigraphy. (author)

  10. Phospho-specific flow cytometry identifies aberrant signaling in indolent B-cell lymphoma

    Directory of Open Access Journals (Sweden)

    Blix Egil S

    2012-10-01

    Full Text Available Abstract Background Knowledge about signaling pathways in malignant cells may provide prognostic and diagnostic information in addition to identify potential molecular targets for therapy. B-cell receptor (BCR and co-receptor CD40 signaling is essential for normal B cells, and there is increasing evidence that signaling via BCR and CD40 plays an important role in the pathogenesis of B-cell lymphoma. The aim of this study was to investigate basal and induced signaling in lymphoma B cells and infiltrating T cells in single-cell suspensions of biopsies from small cell lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL and marginal zone lymphoma (MZL patients. Methods Samples from untreated SLL/CLL and MZL patients were examined for basal and activation induced signaling by phospho-specific flow cytometry. A panel of 9 stimulation conditions targeting B and T cells, including crosslinking of the B cell receptor (BCR, CD40 ligand and interleukins in combination with 12 matching phospho-protein readouts was used to study signaling. Results Malignant B cells from SLL/CLL patients had higher basal levels of phosphorylated (p-SFKs, p-PLCγ, p-ERK, p-p38, p-p65 (NF-κB, p-STAT5 and p-STAT6, compared to healthy donor B cells. In contrast, anti-BCR induced signaling was highly impaired in SLL/CLL and MZL B cells as determined by low p-SFK, p-SYK and p-PLCγ levels. Impaired anti-BCR-induced p-PLCγ was associated with reduced surface expression of IgM and CD79b. Similarly, CD40L-induced p-ERK and p-p38 were also significantly reduced in lymphoma B cells, whereas p-p65 (NF-κB was equal to that of normal B cells. In contrast, IL-2, IL-7 and IL-15 induced p-STAT5 in tumor-infiltrating T cells were not different from normal T cells. Conclusions BCR signaling and CD40L-induced p-p38 was suppressed in malignant B cells from SLL/CLL and MZL patients. Single-cell phospho-specific flow cytometry for detection of basal as well as activation

  11. Naive and effector B-cell subtypes are increased in chronic rhinosinusitis with polyps.

    Science.gov (United States)

    Miljkovic, Dijana; Psaltis, Alkis; Wormald, Peter-John; Vreugde, Sarah

    2018-01-01

    Recent studies demonstrated that B cells and their chemoattractants are elevated in the nasal mucosa of patients with chronic rhinosinusitis (CRS) with nasal polyposis (CRSwNP). However, the presence of naive B cells and of plasmablasts and memory B-cell subsets in the mucosa and periphery of the same patient with CRS is yet to be characterized. Here we sought to quantify naive, plasmablasts, and memory B cells in mucosal tissue and peripheral blood of patients with CRSwNP, patients with CRS without nasal polyps (CRSsNP), and control patients. Polyps, mucosa, and peripheral blood samples were prospectively collected from the patients with CRS and from the non-CRS controls. We used flow cytometry to distinguish among naive, plasmablast, and memory B cells in sinus tissue and peripheral blood. A total of 45 patients were recruited for the study. The patients with CRSwNP had significantly increased mucosal B-cell numbers versus the controls (3.39 ± 4.05% versus 0.39 ± 1.05% of live cells; p Kruskal-Wallis test), which included naive B cells (0.61 ± 0.94 versus 0.11 ± 0.24% of live cells; p Kruskal-Wallis test), plasmablasts (0.06 ± 0.26 versus 0.00 ± 0.00% of live cells; p Kruskal-Wallis test), and memory B cells (0.62 ± 1.26 versus 0.05 ± 0.15% of live cells; p Kruskal-Wallis test). Our study identified increased frequencies of different B-cell subtypes in the mucosa of patients with CRSwNP but not in the peripheral blood. We also found that patients with CRSwNP had significantly increased B-cell subtypes compared with the patients with CRSsNP and the controls. These results implied a potential role for mucosal B cells in the ongoing inflammation in patients with CRSwNP.

  12. Trypanosoma brucei Co-opts NK Cells to Kill Splenic B2 B Cells.

    Directory of Open Access Journals (Sweden)

    Deborah Frenkel

    2016-07-01

    Full Text Available After infection with T. brucei AnTat 1.1, C57BL/6 mice lost splenic B2 B cells and lymphoid follicles, developed poor parasite-specific antibody responses, lost weight, became anemic and died with fulminating parasitemia within 35 days. In contrast, infected C57BL/6 mice lacking the cytotoxic granule pore-forming protein perforin (Prf1-/- retained splenic B2 B cells and lymphoid follicles, developed high-titer antibody responses against many trypanosome polypeptides, rapidly suppressed parasitemia and did not develop anemia or lose weight for at least 60 days. Several lines of evidence show that T. brucei infection-induced splenic B cell depletion results from natural killer (NK cell-mediated cytotoxicity: i B2 B cells were depleted from the spleens of infected intact, T cell deficient (TCR-/- and FcγRIIIa deficient (CD16-/- C57BL/6 mice excluding a requirement for T cells, NKT cell, or antibody-dependent cell-mediated cytotoxicity; ii administration of NK1.1 specific IgG2a (mAb PK136 but not irrelevant IgG2a (myeloma M9144 prevented infection-induced B cell depletion consistent with a requirement for NK cells; iii splenic NK cells but not T cells or NKT cells degranulated in infected C57BL/6 mice co-incident with B cell depletion evidenced by increased surface expression of CD107a; iv purified NK cells from naïve C57BL/6 mice killed purified splenic B cells from T. brucei infected but not uninfected mice in vitro indicating acquisition of an NK cell activating phenotype by the post-infection B cells; v adoptively transferred C57BL/6 NK cells prevented infection-induced B cell population growth in infected Prf1-/- mice consistent with in vivo B cell killing; vi degranulated NK cells in infected mice had altered gene and differentiation antigen expression and lost cytotoxic activity consistent with functional exhaustion, but increased in number as infection progressed indicating continued generation. We conclude that NK cells in T. brucei

  13. B-cell inhibition by cross-linking CD79b is superior to B-cell depletion with anti-CD20 antibodies in treating murine collagen-induced arthritis

    Czech Academy of Sciences Publication Activity Database

    Bruhl, H.; Cihak, J.; Talke, Y.; Rodriguez-Gomez, M.; Hermann, F.; Goebel, N.; Renner, K.; Plachý, Jiří; Stangassinger, M.; Archemann, S.; Nimmerjahn, F.; Mack, M.

    2015-01-01

    Roč. 45, č. 3 (2015), s. 705-715 ISSN 0014-2980 Institutional support: RVO:68378050 Keywords : Arthritis * B cells * B-cell depletion * B-cell inhibition * CD79b * Humoral immune response Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.179, year: 2015

  14. MYC/BCL2 protein coexpression contributes to the inferior survival of activated B-cell subtype of diffuse large B-cell lymphoma and demonstrates high-risk gene expression signatures

    DEFF Research Database (Denmark)

    Hu, Shimin; Xu-Monette, Zijun Y; Tzankov, Alexander

    2013-01-01

    Diffuse large B-cell lymphoma (DLBCL) is stratified into prognostically favorable germinal center B-cell (GCB)-like and unfavorable activated B-cell (ABC)-like subtypes based on gene expression signatures. In this study, we analyzed 893 de novo DLBCL patients treated with R-CHOP (rituximab, cyclo...

  15. Chidamide Combined With R-GDP in Treating Patients With Relapsed or Refractory Diffuse Large B-cell Lymphoma (DLBCL)

    Science.gov (United States)

    2017-12-12

    Chidamide; Lymphoma, B-Cell; Lymphoma, Large B-Cell, Diffuse; Neoplasm by Histology; Neoplasms; Lymphoproliferative Disorders; Lymphatic Diseases; Immunoproliferative Disorders; Immune System Diseases; Lymphoma, Non-Hodgkin; Cyclophosphamide; Rituximab; Gemcitabine; Cisplatin; Dexamethasone; HDAC Inhibitor

  16. Distinct and Overlapping Functions of TEC Kinase and BTK in B Cell Receptor Signaling.

    Science.gov (United States)

    de Bruijn, Marjolein J W; Rip, Jasper; van der Ploeg, Esmee K; van Greuningen, Lars W; Ta, Van T B; Kil, Laurens P; Langerak, Anton W; Rimmelzwaan, Guus F; Ellmeier, Wilfried; Hendriks, Rudi W; Corneth, Odilia B J

    2017-04-15

    The Tec tyrosine kinase is expressed in many cell types, including hematopoietic cells, and is a member of the Tec kinase family that also includes Btk. Although the role of Btk in B cells has been extensively studied, the role of Tec kinase in B cells remains largely unclear. It was previously shown that Tec kinase has the ability to partly compensate for loss of Btk activity in B cell differentiation, although the underlying mechanism is unknown. In this study, we confirm that Tec kinase is not essential for normal B cell development when Btk is present, but we also found that Tec-deficient mature