Key Points• Chronic graft-versus-host disease is associated with a global Breg defect.• This defect is particularly accentuated in the CD24 hi CD27 1 Breg compartment.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 1 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 1 B cells and IL-10-producing CD24 hi CD27 1 B cells. Patients with cGVHD had increased plasmablast frequencies but decreased IL-10-producing plasmablasts. These results suggest a role of CD24 hi CD27 1 B-cell and plasmablast-derived IL-10 in the regulation of human cGVHD. (Blood. 2015;125(11):1830-1839 IntroductionChronic graft-versus-host disease (cGVHD) is the leading cause of morbi-mortality after allogeneic hematopoietic stem cell transplantation (AHSCT). 1 GVHD prevention by means of adoptive transfer of regulatory T cells (Tregs) 2,3 and cGVHD treatment by in vivo induction of Tregs by low-dose interleukin 2 (IL-2) 4,5 may be effective. The exact role of IL-10-producing regulatory B cells (Bregs) in cGVHD is yet to be understood. Bregs have been shown to downmodulate adaptive 6 or innate immune responses 7 in mice and humans. In cGVHD, B cells are essentially recognized as positive regulators of inflammation. 1,8,9 Increased B-cell receptor responsiveness was found in cGVHD patients. 10 B-cell homeostatic defects were described in cGVHD, including elevated B-cell activating factor of the tumor necrosis factor (TNF) family (BAFF)/B-cell ratios, 11-15 expansion of CD21 lo B cells, 16 reduced CD5 1 B1-like cell numbers, 17 decreased CD27 1 memory B cells, and hypogammaglobulinemia. 18 BAFF concentrations correlated with increased circulating pre-germinal center (GC) B-cell and post-GC plasmablast cell counts in patients with cGVHD. 11 B-cell depletion with rituximab prevented cGVHD in humans. 19 Patients with cGVHD frequently have circulating antibodies reactive to recipient cells. 1,9,20 Besides their functions in antibody secretion, cytokine and chemokine production, and antigen presentation, B cells exhibit regulatory properties in several human autoimmune diseases including systemic lupus erythemat...
A guiding principle for HIV vaccine design has been that cellular and humoral immunity work together to provide the strongest degree of efficacy. However, three efficacy trials of Ad5-vectored HIV vaccines showed no protection. Transmission was increased in two of the trials, suggesting that this vaccine strategy elicited CD4+ T-cell responses that provide more targets for infection, attenuating protection or increasing transmission. The degree to which this problem extends to other HIV vaccine candidates is not known. Here, we show that a gp120-CD4 chimeric subunit protein vaccine (full-length single chain) elicits heterologous protection against simian-human immunodeficiency virus (SHIV) or simian immunodeficiency virus (SIV) acquisition in three independent rhesus macaque repeated low-dose rectal challenge studies with SHIV162P3 or SIVmac251. Protection against acquisition was observed with multiple formulations and challenges. In each study, protection correlated with antibody-dependent cellular cytotoxicity specific for CD4-induced epitopes, provided that the concurrent antivaccine T-cell responses were minimal. Protection was lost in instances when T-cell responses were high or when the requisite antibody titers had declined. Our studies suggest that balance between a protective antibody response and antigen-specific T-cell activation is the critical element to vaccine-mediated protection against HIV. Achieving and sustaining such a balance, while enhancing antibody durability, is the major challenge for HIV vaccine development, regardless of the immunogen or vaccine formulation.
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