Chronic Myeloid Leukemia Patients on Tyrosine Kinase Inhibitor Have Normal T Cell Responses to Vaccination but An Impaired IgM Humoral Response Associated with Loss of Discrete Memory B Cell Subsets,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3753-3753
Author(s):  
Hugues de Lavallade ◽  
David Marin ◽  
Melanie Hart ◽  
Takuya Sekine ◽  
Ian Gabriel ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
T Cell Responses ◽  
Healthy Controls ◽  
Memory B Cell ◽  
Cell Responses ◽  
B Cell Subsets

Abstract Abstract 3753 The tyrosine kinase inhibitors (TKIs) imatinib (IM), nilotinib (NIL) and dasatinib (DAS) are remarkably effective as single-agent therapy for chronic myeloid leukemia (CML) in chronic phase (CP). However little is known of their potential impact on the immune response. No human in vivo studies to assess how these molecular-targeted drugs affect immune function in patients are available and data from in vitro and animal studies with imatinib have been contradictory, ranging from impaired antigen-specific T-cell response to enhanced stimulation of tolerant T cells. Furthermore, although the immunomodulatory effects of TKIs on T cells, NK cells and dendritic cells have been explored in vitro, little is known of their potential impact on B cells. To characterize the in vivo immunomodulatory effects of TKIs, 51 patients with CP-CML in complete cytogenetic response (CCyR) on standard dose IM (n=26), DAS (n=14) or NIL (n=12) and 28 adult controls were recruited during two influenza seasons (2008 and 2009). Patients and controls were concomitantly immunized with an influenza vaccine (Ph. Eur. 2008/2009 or Ph. Eur. 2009/2010, CSL Biotherapies) and with the 23-valent polysaccharide pneumococcal vaccine (Pneumovax II; Sanofi Pasteur MSD). Peripheral blood mononuclear cells (PBMCs) and serum samples were collected from patients and donors prior to vaccination and T and B responses to vaccination were assessed at 4 weeks and at 2–3 months post-immunization. T-cell responses to influenza vaccine were analyzed quantitatively and qualitatively using flow cytometry and intracellular cytokine assay for TNF-α, IFN-γ, IL-2 and the cytotoxicity marker CD107a. Serum titers of IgM and IgG pneumococcal antibodies were determined by ELISA. Analysis of B cell subsets was performed using flow cytometry and correlated with the pneumococcal IgM and IgG humoral response. Following vaccination, Flu-specific T cells were detected in 24/51 (47.0%) patients on TKI and 15/24 (62.5%) healthy controls (p=0.16). Polyfunctional T-cell responses (defined as the production of 2 or more cytokines or one cytokine and the cytotoxic marker CD107a) were induced in 6/10 evaluable patients and 4/8 normal controls (p=1.0). T-cell independent humoral responses to vaccination were assessed in 45 patients and 12 healthy controls by measuring pneumococcal IgM titers. Four weeks postimmunization, 11/12 (92%) controls achieved IgM pneumococcal Ab titers >80 U/ml compared to only 23/45 (53%) CML patients on TKI (p=0.010). The pneumococcal IgM titers were significantly lower in patients with CML on TKI compared to healthy controls (median, 89.0 U/ml, range 5–200 vs 200 U/ml, range 58–200, p=0.0006), suggesting that CML patients on TKI have impaired IgM responses to vaccination. To further characterize the humoral immune response to Pneumovax, we stratified CML patients based on their pneumococcal IgM titers. We found a significantly lower percentage of IgM memory B cell subset in CML patients who failed to mount a significant pneumococcal IgM response compared to patients who achieved a pneumococcal IgM response (median, 6.25% vs 16.4%, p=0.0059) and healthy controls (median, 6.25% vs 14.3%, p=0.0086). Furthermore, we found a significant correlation between anti-pneumococcal IgM titers and IgM memory B cell percentage (Spearman rank correlation test, r=0.61, p<.0001). To investigate a putative role of TKIs for the loss of IgM memory B cell subsets in CML patients, we determined the frequencies of IgM memory B cells in paired samples collected from 15 CML-CP patients at diagnosis (i.e. prior to initiating IM) and once CCyR was achieved. We found a significant decrease in the percentage of IgM memory B cells in CML-CP patients treated with IM compared to the pre-treatment sample (median 9.4%, vs. 15.2% respectively, p=0.0023). In summary, patients with CML on TKIs can mount effective T-cell immune responses to influenza vaccination. Our data suggest that TKIs (IM, DAS and NIL) impair T-cell independent humoral immune responses, namely IgM responses to vaccination. This is associated with a loss of IgM memory B cell subsets. Further investigations to understand the mechanisms by which TKIs may impact B-cell subsets are underway. These results are of particular interest in terms of the long-term effects of TKI on tumor immune surveillance and susceptibility to infections and may have implication for vaccination strategies in CML patients. Disclosures: No relevant conflicts of interest to declare.

scholarly journals B Cell Requirement for Robust Regulatory T Cell Responses to Friend Retrovirus Infection

mBio ◽  
2017 ◽  
Vol 8 (4) ◽  
Author(s):  
Tyler C. Moore ◽  
Lorena M. Gonzaga ◽  
Jennifer M. Mather ◽  
Ronald J. Messer ◽  
Kim J. Hasenkrug
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Regulatory T Cells ◽  
B Cell ◽  
T Cell Responses ◽  
Host Cells ◽  
Virus Control ◽  
Cell Responses

ABSTRACTRegulatory T cells (Tregs) are immunosuppressive cells of the immune system that control autoimmune reactivity. Tregs also respond during immune reactions to infectious agents in order to limit immunopathological damage from potent effectors such as CD8+cytolytic T lymphocytes. We have used the Friend virus (FV) model of retroviral infection in mice to investigate how viral infections induce Tregs. During acute FV infection, there is significant activation and expansion of thymus-derived (natural) Tregs that suppress virus-specific CD8+T cell responses. Unlike conventional T cells, the responding Tregs are not virus specific, so the mechanisms that induce their expansion are of great interest. We now show that B cells provide essential signals for Treg expansion during FV infection. Treg responses are greatly diminished in B cell-deficient mice but can be restored by adoptive transfers of B cells at the time of infection. The feeble Treg responses in B cell-deficient mice are associated with enhanced virus-specific CD8+T cell responses and accelerated virus control during the first 2 weeks of infection.In vitroexperiments demonstrated that B cells promote Treg activation and proliferation through a glucocorticoid-induced receptor superfamily member 18 (GITR) ligand-dependent mechanism. Thus, B cells play paradoxically opposing roles during FV infection. They provide proliferative signals to immunsosuppressive Tregs, which slows early virus control, and they also produce virus-specific antibodies, which are essential for long-term virus control.IMPORTANCEWhen infectious agents invade a host, numerous immunological mechanisms are deployed to limit their replication, neutralize their spread, and destroy the host cells harboring the infection. Since immune responses also have a strong capacity to damage host cells and tissues, their magnitude, potency, and duration are under regulatory control. Regulatory T cells are an important component of this control, and the mechanisms that induce them to respond and exert immunosuppressive regulation are of great interest. In the current report, we show that B cells, the cells responsible for making pathogen-specific antibodies, are also involved in promoting the expansion of regulatory T cells during a retroviral infection.In vitrostudies demonstrated that they do so via stimulation of the Tregs through interactions between cell surface molecules: GITR interactions with its ligand (GITRL) on B cells and GITR on regulatory T cells. These findings point the way toward therapeutics to better treat infections and autoimmune diseases.

scholarly journals B cell depletion impairs vaccination-induced CD8+ T cell responses in a type I interferon-dependent manner

2021 ◽  
pp. annrheumdis-2021-220435
Author(s):  
Theresa Graalmann ◽  
Katharina Borst ◽  
Himanshu Manchanda ◽  
Lea Vaas ◽  
Matthias Bruhn ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Expansion ◽  
De Novo ◽  
T Cell Responses ◽  
Type I ◽  
Cell Responses ◽  
T Cell Expansion

ObjectivesThe monoclonal anti-CD20 antibody rituximab is frequently applied in the treatment of lymphoma as well as autoimmune diseases and confers efficient depletion of recirculating B cells. Correspondingly, B cell-depleted patients barely mount de novo antibody responses during infections or vaccinations. Therefore, efficient immune responses of B cell-depleted patients largely depend on protective T cell responses.MethodsCD8+ T cell expansion was studied in rituximab-treated rheumatoid arthritis (RA) patients and B cell-deficient mice on vaccination/infection with different vaccines/pathogens.ResultsRituximab-treated RA patients vaccinated with Influvac showed reduced expansion of influenza-specific CD8+ T cells when compared with healthy controls. Moreover, B cell-deficient JHT mice infected with mouse-adapted Influenza or modified vaccinia virus Ankara showed less vigorous expansion of virus-specific CD8+ T cells than wild type mice. Of note, JHT mice do not have an intrinsic impairment of CD8+ T cell expansion, since infection with vaccinia virus induced similar T cell expansion in JHT and wild type mice. Direct type I interferon receptor signalling of B cells was necessary to induce several chemokines in B cells and to support T cell help by enhancing the expression of MHC-I.ConclusionsDepending on the stimulus, B cells can modulate CD8+ T cell responses. Thus, B cell depletion causes a deficiency of de novo antibody responses and affects the efficacy of cellular response including cytotoxic T cells. The choice of the appropriate vaccine to vaccinate B cell-depleted patients has to be re-evaluated in order to efficiently induce protective CD8+ T cell responses.

scholarly journals B cell depletion with anti-CD20 mAb exacerbates anti-donor CD4+ T cell responses in highly sensitized transplant recipients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Asuka Tanaka ◽  
Kentaro Ide ◽  
Yuka Tanaka ◽  
Masahiro Ohira ◽  
Hiroyuki Tahara ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
T Cell Responses ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Transplant Recipients ◽  
Cell Responses ◽  
Anti Cd20

AbstractPretransplant desensitization with rituximab has been applied to preformed donor-specific anti-human leukocyte antigen antibody (DSA)-positive recipients for elimination of preformed DSA. We investigated the impact of pretransplant desensitization with rituximab on anti-donor T cell responses in DSA-positive transplant recipients. To monitor the patients’ immune status, mixed lymphocyte reaction (MLR) assays were performed before and after desensitization with rituximab. Two weeks after rituximab administration, the stimulation index (SI) of anti-donor CD4+ T cells was significantly higher in the DSA-positive recipients than in the DSA-negative recipients. To investigate the mechanisms of anti-donor hyper responses of CD4+ T cells after B cell depletion, highly sensitized mice models were injected with anti-CD20 mAb to eliminate B cells. Consistent with clinical observations, the SI values of anti-donor CD4+ T cells were significantly increased after anti-CD20 mAb injection in the sensitized mice models. Adding B cells isolated from untreated sensitized mice to MLR significantly inhibited the enhancement of anti-donor CD4+ T cell response. The depletion of the CD5+ B cell subset, which exclusively included IL-10-positive cells, from the additive B cells abrogated such inhibitory effects. These findings demonstrate that IL-10+ CD5+ B cells suppress the excessive response of anti-donor CD4+ T cells responses in sensitized recipients.

scholarly journals Ectopic Lymphoid Follicles in Multiple Sclerosis: Centers for Disease Control?

2020 ◽  
Vol 11 ◽  
Author(s):  
Austin Negron ◽  
Olaf Stüve ◽  
Thomas G. Forsthuber
Keyword(s):  
Multiple Sclerosis ◽  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
T Cell Responses ◽  
Memory B Cells ◽  
Lymphoid Follicles ◽  
Cell Responses ◽  
B Cell Responses

While the contribution of autoreactive CD4+ T cells to the pathogenesis of Multiple Sclerosis (MS) is widely accepted, the advent of B cell-depleting monoclonal antibody (mAb) therapies has shed new light on the complex cellular mechanisms underlying MS pathogenesis. Evidence supports the involvement of B cells in both antibody-dependent and -independent capacities. T cell-dependent B cell responses originate and take shape in germinal centers (GCs), specialized microenvironments that regulate B cell activation and subsequent differentiation into antibody-secreting cells (ASCs) or memory B cells, a process for which CD4+ T cells, namely follicular T helper (TFH) cells, are indispensable. ASCs carry out their effector function primarily via secreted Ig but also through the secretion of both pro- and anti-inflammatory cytokines. Memory B cells, in addition to being capable of rapidly differentiating into ASCs, can function as potent antigen-presenting cells (APCs) to cognate memory CD4+ T cells. Aberrant B cell responses are prevented, at least in part, by follicular regulatory T (TFR) cells, which are key suppressors of GC-derived autoreactive B cell responses through the expression of inhibitory receptors and cytokines, such as CTLA4 and IL-10, respectively. Therefore, GCs represent a critical site of peripheral B cell tolerance, and their dysregulation has been implicated in the pathogenesis of several autoimmune diseases. In MS patients, the presence of GC-like leptomeningeal ectopic lymphoid follicles (eLFs) has prompted their investigation as potential sources of pathogenic B and T cell responses. This hypothesis is supported by elevated levels of CXCL13 and circulating TFH cells in the cerebrospinal fluid (CSF) of MS patients, both of which are required to initiate and maintain GC reactions. Additionally, eLFs in post-mortem MS patient samples are notably devoid of TFR cells. The ability of GCs to generate and perpetuate, but also regulate autoreactive B and T cell responses driving MS pathology makes them an attractive target for therapeutic intervention. In this review, we will summarize the evidence from both humans and animal models supporting B cells as drivers of MS, the role of GC-like eLFs in the pathogenesis of MS, and mechanisms controlling GC-derived autoreactive B cell responses in MS.

scholarly journals Characterization and Development of T-Cell Immune Responses in B-Cell-Deficient (Igh-6−/−) Mice with Salmonella enterica Serovar TyphimuriumInfection

2003 ◽  
Vol 71 (12) ◽  
pp. 6808-6819 ◽  
Author(s):  
Sanja Ugrinovic ◽  
Nathalie Ménager ◽  
Natalie Goh ◽  
Pietro Mastroeni
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Salmonella Enterica ◽  
Early Stage ◽  
T Cell Responses ◽  
Costimulatory Molecules ◽  
Cell Responses ◽  
Serovar Typhimurium

ABSTRACT Infection of mice with Salmonella enterica serovar Typhimurium induces strong Th1 T-cell responses that are central to the control of the infection. In the present study, we examined the role of B cells in the development of Th1 T-cell responses to Salmonella by using gene-targeted B-cell-deficient mice (Igh-6−/− mice). The development of Th1 T-cell responses in Igh-6−/− mice was impaired in the early stage of a primary infection. This impairment persisted throughout the course of the disease. The ability of T cells to produce the Th1 cytokine gamma interferon and the frequency at which they did so were lower in Igh-6−/− mice than in control mice. We also observed a transient switch toward Th2 cytokine production in Igh-6−/− mice. Thus, B cells are important for the induction of protective Th1 T-cell responses in the early phase of a Salmonella infection. Activated B cells express high levels of major histocompatibility complex and costimulatory molecules and are nearly as effective as dendritic cells in their antigen-presenting cell (APC) activity. However, their importance as APCs in infection and their role in initiating and/or maintaining T-cell responses are unknown. Here, we show that B cells upregulate costimulatory molecules upon in vitro stimulation with S. enterica serovar Typhimurium and that they can present Salmonella antigens to Salmonella-specific CD4+ T cells. Our results show that B cells are important for the development of T-cell responses in the early stage of a Salmonella infection and that this property may be due to their ability to present antigens to T cells.

scholarly journals Effects of Friend Virus Infection and Regulatory T Cells on the Antigen Presentation Function of B Cells

mBio ◽  
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Tyler C. Moore ◽  
Ronald J. Messer ◽  
Lorena M. Gonzaga ◽  
Jennifer M. Mather ◽  
Aaron B. Carmody ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Regulatory T Cells ◽  
B Cell ◽  
Cell Activation ◽  
T Cell Responses ◽  
B Cell Activation ◽  
Friend Virus ◽  
Cell Responses

ABSTRACTFriend virus (FV) is a naturally occurring mouse retrovirus that infects dividing cells of the hematopoietic lineage, including antigen-presenting cells (APCs). The infection of APCs by viruses often induces their dysfunction, and it has been shown that FV infection reduces the ability of dendritic cells (DCs) to prime critical CD8+T cell responses. Nonetheless, mice mount vigorous CD8+T cell responses, so we investigated whether B cells might serve as alternative APCs during FV infection. Directex vivoanalysis of B cells from FV-infected mice revealed that infected but not uninfected B cells upregulated expression of the costimulatory molecules CD80, CD86, and CD40, as well as major histocompatibility complex class II (MHC-II) molecules. Furthermore,in vitrostudies showed that, compared to uninfected B cells from the same mice, the FV-infected B cells had significantly enhanced APC function, as measured by their capacity to prime CD8+T cell activation and proliferation. Thus, in contrast to DCs, infection of B cells with FV enhanced their APC capacity and ability to stimulate the CD8+T cell responses essential for virus control. FV infections also induce the activation and expansion of regulatory T cells (Tregs), so it was of interest to determine the impact of Tregs on B cell activation. The upregulation of costimulatory molecule expression and APC function of B cells was even more strongly enhanced byin vivodepletion of regulatory T cells than infection. Thus, Tregs exert potent homeostatic suppression of B cell activation that is partially overcome by FV infection.IMPORTANCEThe primary role of B cells in immunity is considered the production of pathogen-specific antibodies, but another, less-well-studied, function of B cells is to present foreign antigens to T cells to stimulate their activation and proliferation. Dendritic cells (DCs) are considered the most important antigen-presenting cells (APCs) for CD8+T cells, but DCs lose APC function when infected with Friend virus (FV), a model retrovirus of mice. Interestingly, B cells were better able to stimulate CD8+T cell responses when they were infected with FV. We also found that the activation status of B cells under homeostatic conditions was potently modulated by regulatory T cells. This study illustrates an important link between B cell and T cell responses and illustrates an additional mechanism by which regulatory T cells suppress critical T cell responses during viral infections.

scholarly journals TNFRSF14 aberrations in Follicular Lymphoma B Cells Result in Increased Alloresponses in Vitro and in Vivo

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2426-2426 ◽  
Author(s):  
Eleni Kotsiou ◽  
Jessica Okosun ◽  
Andrew James Clear ◽  
Sameena Iqbal ◽  
Jude Fitzgibbon ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Lymph Nodes ◽  
Follicular Lymphoma ◽  
T Cell Responses ◽  
Cell Responses ◽  
Significant Difference ◽  
The Impact

Abstract Introduction Genetic aberrations of Tumor Necrosis Factor Receptor Superfamily 14 (TNFRSF14, also known as HVEM) have been shown to occur at high frequencies in patients (pts) with follicular lymphoma (FL). HVEM is a ligand for B and T lymphocyte attenuator (BTLA) which negatively regulates T cell responses and BTLA stimulation reduces acute graft-versus-host disease (aGvHD) in murine allogeneic hematopoietic cell transplantation (AHCT) models. As activated FL B cells are potent alloantigen presenting cells, we hypothesized that TNFRSF14 aberrations in FL B cells would reduce expression of HVEM and potentiate capacity of FL B cells to stimulate allogeneic T cell responses. We therefore sought to determine the functional effect of TNFRSF14 aberrations on FL B cell-stimulated donor T cell alloresponses in vitro. We also examined the impact of TNFRSF14 aberrations on the outcome of FL pts after HLA-matched reduced intensity conditioning (RIC) AHCT. Results FL B cells from lymph nodes were FACS-sorted (>90% purity and > 95% light chain restriction), activated and used as stimulators in mixed lymphocyte reactions with purified allogeneic responder CD3+ T cells. HVEM expression on FL B cells from pts with biallelic TNFRSF14 aberrations (Mut/Del cases) was undetectable whereas 40% of FL B cells from TNFRSF14 WT cases expressed HVEM (Fig 1 A). In contrast, FL B cells from Mut/Del and WT cases expressed similar levels of MHC class I/II, CD80, CD86 and CD58 before and after activation. Allostimulation with Mut/Del FL B cells resulted in significantly greater expression of activation markers on responder CD4+ T cells, increased secretion of pro-inflammatory cytokines (IFN-γ, TNF-α, and IL-2) measured by ELISA and increased frequencies of cytokine-secreting CD4+ and CD8+ T cells enumerated by intracellular cytokine staining. Responder T cell proliferation by thymidine incorporation was significantly greater after stimulation with Mut/Del FL B cells compared to WT FL B cells. CFSE labeling studies demonstrated that this effect resulted from increased proliferation of CD4+ and CD8+ responder T cells after both primary (Fig 1B) and secondary allostimulation. To determine if the increased alloresponses we observed using FL B cells from TNFRSF14 Mut/Del cases was due to reduced HVEM-BTLA signaling, we performed allogeneic co-cultures in the presence of antagonist or agonist BTLA antibodies (ab). Antagonist anti-BTLA ab increased proliferation of responder T cells after stimulation with WT FL B cells confirming that BTLA limits alloresponses in our in vitro model. Importantly, agonist BTLA ab reduced alloresponses stimulated by Mut/Del FL B cells. We next sought to determine if the increased alloresponses we detected in vitro in FL pts with TNFRSF14 aberrations resulted in an increase in clinical alloreactivity after AHCT. DNA from lymph nodes from FL pts undergoing T-cell replete RIC AHSCT was screened for TNFRSF14 mutations and deletions by Sanger sequencing and multiplex ligation-probe amplification respectively. Cumulative incidences (CI) of aGvHD and GvHD-related death were calculated with FL progression as a competing risk. TNFRSF14 aberrations were identified in 10/21 pts prior to RIC AHCT (4 Mut/Del, 1 Del/Del, 1 Mut/WT, 4 Del/WT). Most (18/21) pts had evidence of ongoing FL pre-transplant. Disease and donor characteristics were similar in pts with and without aberrations. There was no significant difference in CI of aGvHD in pts with or without TNFRSF14 aberrations. However there was a significantly higher CI of fatal aGvHD in patients with TNFRSF14 aberrations (45%) compared to those without aberrations (0%, p<0.01). Interestingly, relapse was less frequent in patients with TNFRSF14 aberrations consistent with increased graft-versus-tumor effects, although this did not reach statistical significance. Conclusion This study is the first to describe the impact of TNFRSF14 aberrations on the allostimulatory capacity of FL B cells. TNFRSF14 aberrations were associated with enhanced T-cell alloresponses in vitro and increased death from aGvHD. Importantly, our results suggest FL patients with TNFRSF14 aberrations may benefit from more aggressive immunosuppression to prevent fatal aGvHD after AHCT. The increased antigen-presenting capacity of FL B cells with TNFRSF14 aberrations could also influence autologous anti-tumor responses and impact outcome after other treatment modalities. Figure 1 Figure 1. Disclosures Gribben: Celgene: Research Funding; Pharmacyclics: Honoraria; Roche: Honoraria.

Regulatory B Cell Defects In Patients with Immune Thrombocytopenia (ITP)

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 379-379 ◽  
Author(s):  
Xiaojuan Li ◽  
Hui Zhong ◽  
Weili Bao ◽  
Nayla Boulad ◽  
James B. Bussel ◽  
...  
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Board Of Directors ◽  
Research Funding ◽  
T Cell Responses ◽  
Healthy Controls ◽  
Advisory Committees ◽  
Cell Responses ◽  
Regulatory Capacity

Abstract Abstract 379 B lymphocytes participate in immune responses through production of antibodies, antigen presentation to T cells, and cytokine secretion. In ITP, B cells that produce platelet-specific autoantibodies play a major role in the pathogenesis of disease. Recent data from mouse models of autoimmune and inflammatory diseases suggest that B cells have regulatory functions mediated by the production of regulatory cytokines such as IL-10 and/or through inhibitory interactions with effector T cells. In humans, CD19+CD24hiCD38hi B cells, originally identified as immature transitional B cells, were recently shown to possess regulatory capacity mediated in part by IL-10. Given that ITP pathogenesis is in part related to defective T helper functions and since Bregs are important for controlling CD4+ T cell responses, we initiated studies to characterize the CD19+CD24hiCD38hi B cell compartment in ITP patients. Phenotypic analysis in patients with ITP showed statistically significant increases in the frequency of CD19+CD24hiCD38hi B cells (13.2± 1.5% versus 7.7±0.6%, p=0.0015) as well as in the percentage of CD19+CD24hiCD38int mature B cells (72.0± 1.7% versus 62.3±1.6%, p=0.0003). In contrast there was a pronounced decrease in CD19+CD24hiCD38− memory B cells (9.3± 2% versus 26.2±2%, p<0.0001 as confirmed by expression of CD27 memory marker) in patients (n=23) compared to healthy controls (n=23). The suppressive capacity of human CD19+CD24hiCD38hi Bregs involves CD80. We found a statistically significant decrease in the overall frequency of CD80 expressing CD19+ B cells in ITP patients compared to healthy controls (12.40± 1.3% versus 21.8±2.1%, p=0.002), indicating that despite the increase in the Breg frequency, their regulatory capacity may be impaired. To determine the functional activity of the Bregs, PBMCs from 4 patients with ITP were depleted of CD19+CD24hiCD38hi B cells by cell sorting and levels of cytokine production in the CD4+ T cell population following stimulation with plate-bound anti-CD3 for 72h was evaluated. As has been reported previously, we observed a >30% increase in the frequency of CD4+IFN-g+ in CD19+CD24hiCD38hi B cell-depleted compared with non-depleted PBMCs from healthy controls. However, depletion of CD19+CD24hiCD38hi B cells from PBMCs of ITP patients did not alter CD4+IFN-g+ production in 3 /4 patients, indicating a possible defect in the suppressive activity of Bregs in those 3 patients. IL-10 secretion following CD40 engagement in human Bregs is pivotal in mediating their suppressive activity. Given that platelets express CD40L, we tested the ability of Bregs to respond to platelets. We found two-fold lower IL-10 production in CD19+CD24hiCD38hi Bregs (1.9±2.1%, versus 5.0± 1.0%, p<0.05), but not in CD19+CD24hiCD38− B cells (p=0.9) from patients (n=3, different from above) compared to controls (n=5) when PBMCs were stimulated with acid-treated platelets (to remove HLA molecules) from normal controls, indicating a defect in IL-10 production in the Breg population in patients with ITP. Altogether, our in vitro studies of circulating Bregs suggest that these cells may be functionally compromised in some patients with ITP patients as indicated by reduced IL-10 production and indirectly by Breg depletion studies showing inability to dampen effector T cell responses. Given the important role of Bregs in controlling CD4+T responses, the data implicates defective Bregs as an additional mechanism to explain increased T cell responses in patients with ITP. The impaired Breg activity may also explain the variability in response to treatment with anti-CD20 in patients with ITP. It may be that B cell depletion therapy in patients who have defective Breg activity will result in the removal of primarily pathogenic B cells and therefore these patients will have a good response to rituximab treatment. However, in patients with intact Bregs, the same treatment will deplete both pathogenic and regulatory B cells, causing a less effective response. Ongoing studies to test patients' platelets as well as CD40-specific Breg responsiveness are currently underway to further explore the role of Bregs in the pathogenesis of ITP. Disclosures: Bussel: Portola: Consultancy; Amgen: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding; GlaxoSmithKline: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding; Ligand: Membership on an entity's Board of Directors or advisory committees, Research Funding; Shionogi: Membership on an entity's Board of Directors or advisory committees, Research Funding; Eisai, Inc.: Membership on an entity's Board of Directors or advisory committees; Cangene: Research Funding; Genzyme: Research Funding.

B Cell With Regulatory Function Are Enriched Within Transitional and IgM Memory B Cell Subsets In Healthy Donors But Are Reduced and Functionally Impaired In Patients With Chronic Graft-Versus-Host Disease

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4478-4478
Author(s):  
Anushruti Sarvaria ◽  
Ahmad Khoder ◽  
Abdullah Alsuliman ◽  
Claude Chew ◽  
Takuya Sekine ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cd4 T Cells ◽  
Memory B Cells ◽  
Regulatory Function ◽  
Healthy Controls ◽  
Transitional B Cells ◽  
B Cell Subsets

The immunosuppressive function of IL10 producing regulatory B cells (Bregs) has been shown in several murine models of inflammation and autoimmune disease. However, there is a paucity of data regarding the existence of an equivalent regulatory B cell subset in healthy individuals and their potential role in the pathogenesis of chronic graft-versus-host disease (cGVHD) remains unknown. Here, we examined the functional regulatory properties of peripheral blood (PB)-derived human B cell subsets from healthy individuals. In addition, we carried out studies to explore their role in cGVHD, using B cells from patients following allogeneic stem cell transplantation (HSCT). We first determined whether human IL-10 producing B cells are enriched within any othe previously described human B cell subsets: CD19+IgM+CD27+ IgM memory, CD19+IgM-CD27+ switched memory, CD19+IgM+CD27- naive, and and transitional CD19+CD24hiCD38hi. Following in vitro stimulation with CD40 ligand, the majority of IL-10 producing B cells were found within the CD24hiCD38hi transitional and CD19+IgM+CD27+B cell subsets. We next assessed the regulatory properties of the PB-derived B cell subsets, by sort-purifying IgM memory (CD19+IgM+CD27+), switched memory (CD19+IgM-CD27+), naïve (CD19+IgM+CD27-) and transitional (CD19+CD24hiCD38hi) B cells from healthy controls, and cultured them 1:1 with autologous magnetic-bead purified CD4+ T cells. CD3/CD28 stimulated CD4+ T cells cultured with either CD19+IgM+CD27- naïve or CD19+IgM-CD27+ switched memory B cells proliferated to the same extent and produced equivalent amounts of IFN-γ to cultures containing CD4+ T cells alone. In contrast, culture of CD4+ T cells with IgM memory and transitional B cells significantly suppressed CD4+ T cell proliferation [median percent proliferating CD4+ T cells 52.5%; (33%-75%)] and 51% (25%-63%)], respectively when compared with CD3/CD28 stimulated CD4+ T cells (positive control) [89.5% (75%-92%], p=0.0001. The inhibitory effect of IgM memory and transitional B cells on CD4+ T cell proliferation was cell dose dependent with the highest suppression observed at a ratio of 1:1. These data suggest that human PB transitional and IgM memory B cells are endowed with regulatory function. We next examined if the in vitro suppressive effect of transitional and IgM memory B cells is mediated by regulatory T cells (Tregs). For this purpose, CD4+ T cells were depleted of CD127lo CD25hi CD4+ T cells by magnetic cell purification. B cell subsets were cultured with CD3/CD28 stimulated CD4+ CD25- T cells at a ratio of 1:1. IgM memory and transitional B cells were able to significantly suppress the proliferation and Th1 cytokine response by CD4+ CD25- T cells compared to cultures containing CD4+ CD25-T cells alone, indicating that the suppressive activity of Bregs is independent of Tregs. To further understand the underlying mechanims though which Bregs exert T-cell suppression, we used antibody blockade experiments and showed that this suppressive effect was mediated partially via the provision of IL-10, but not TGF-ß. Using transwell experiments, we further determined that the suppressive function of Bregs is also partly dependent on direct T cell/B cell contact. We next assessed whether the activity of Breg cells might be altered in patients with cGVHD. B cells from patients with cGVHD were refractory to CD40 stimulation and produced less IL-10 when compared to patients without cGVHD post-SCT and healthy controls, [1.02% (0.22-2.26) vs.1.72% (0.8-5.52) vs. 2.16 (1.3- 5.6), p=0.001]. Likewise, the absolute number of IL-10 producing B cells was significantly lower in cGvHD patients compared to patients without cGVHD and healthy controls (p=0.007), supporting both a qualitative and quantitative defect in IL-10 producing B cells in cGvHD. Our combined studies provide important new data defining the phenotype of B cell populations enriched in regulatory B cells in healthy humans and provide evidence for a defect in the activity of such cells in patients with cGVHD post-SCT. In association with previous reports showing defects in Treg cell activity in GVHD, our results suggest the existence of a broad range of deficiencies in immune regulatory cell function in cGvHD patients. * Both Anushruti Sarvaria and Ahmad K contributed equally. Disclosures: No relevant conflicts of interest to declare.

scholarly journals B cells with aberrant activation of Notch1 signaling promote Treg and Th2 cell–dominant T-cell responses via IL-33

2018 ◽  
Vol 2 (18) ◽  
pp. 2282-2295 ◽  
Author(s):  
Hiroshi Arima ◽  
Momoko Nishikori ◽  
Yasuyuki Otsuka ◽  
Wataru Kishimoto ◽  
Kiyotaka Izumi ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Notch Signaling ◽  
Cd8 T Cells ◽  
T Cell Responses ◽  
Cell Responses ◽  
Th2 Cell

Abstract The Notch-signaling pathway in a variety of mature B-cell neoplasms is often activated by gene alterations, but its role remains unclear. Here, we show that B cells harboring dysregulated activation of Notch1 signaling have an immunomodulatory effect on T cells by amplifying regulatory T (Treg) and T helper 2 (Th2) cell responses in an interleukin-33 (IL-33)-dependent manner. A conditional mouse model, in which constitutive expression of an active form of Notch1 is induced in B cells by Aicda gene promoter-driven Cre recombinase, revealed no obvious phenotypic changes in B cells; however, mice demonstrated an expansion of Treg and Th2 cell subsets and a decrease in cytokine production by Th1 and CD8+ T cells. The mice were susceptible to soft tissue sarcoma and defective production of CD8+ T cells specific for inoculated tumor cells, suggesting impaired antitumor T-cell activity. Gene-expression microarray revealed that altered T-cell responses were due to increased IL-33 production by Notch1-activated B cells. Knockout of IL33 or blockade of IL-33 by a receptor-blocking antibody abrogated the Treg and Th2 cell–dominant T-cell response triggered by B cells. Gene-expression data derived from human diffuse large B-cell lymphoma (DLBCL) samples showed that an activated Notch-signaling signature correlates positively with IL33 expression and Treg cell–rich gene-expression signatures. These findings indicate that B cells harboring dysregulated Notch signaling alter T-cell responses via IL-33, and suggest that aberrant activation of Notch signaling plays a role in fostering immune privilege in mature B-cell neoplasms.

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