The influence of effector T cells and Fas ligand on lupus-associated B cells.

The Wistar Institute, Room 276, 3601 Spruce Street, Philadelphia, PA 19104, USA.
The Journal of Immunology (Impact Factor: 5.52). 08/2005; 175(1):104-11.
Source: PubMed

ABSTRACT Circulating autoantibodies against dsDNA and chromatin are a characteristic of systemic lupus erythematosus in humans and many mouse models of this disease. B cells expressing these autoantibodies are normally regulated in nonautoimmune-prone mice but are induced to secrete Abs following T cell help. Likewise, anti-chromatin autoantibody production is T cell-dependent in Fas/Fas ligand (FasL)-deficient (lpr/lpr or gld/gld) mice. In this study, we demonstrate that Th2 cells promote anti-chromatin B cell survival and autoantibody production in vivo. FasL influences the ability of Th2 cells to help B cells, as Th2-gld/gld cells support higher titers of anti-chromatin Abs than their FasL-sufficient counterparts and promote anti-chromatin B cell participation in germinal centers. Th1 cells induce anti-chromatin B cell germinal centers regardless of FasL status; however, their ability to stimulate anti-chromatin Ab production positively correlates with their level of IFN-gamma production. This distinction is lost if FasL-deficient T cells are used: Th1-gld/gld cells promote significant titers of anti-chromatin Abs regardless of IFN-gamma production levels. Thus, FasL from effector T cells plays an important role in determining the fate of anti-chromatin B cells.

  • [Show abstract] [Hide abstract]
    ABSTRACT: A series of checkpoints for antigen receptor fitness and specificity during B cell development ensures the elimination or anergy of primary, high-avidity-autoantigen-reactive B cells. Defects in genes encoding molecules with which this purging of the original B cell repertoires is achieved may break this B cell tolerance, allowing the development of B cell- and autoantibody-mediated immune diseases. Furthermore, whenever tolerance of helper T cells to a part of an autoantigen is broken, a T cell-dependent germinal center-type response of the remaining low--or no--autoreactive B cells is activated. It induces longevity of these B cells, and expression of AiD, which effects Ig class switching and IgV-region hypermutation. The development of V-region-mutant B cells and the selections of high-avidity-autoantigen-reactive antibodies producing B cells by autoantigens from them, again, can lead to the development and propagation of autoimmune diseases such as lupus erythematosus or chronic inflammatory rheumatoid arthritis by the autoantibody BcR-expressing B cells and their secreted autoantibodies.
    Current topics in microbiology and immunology 02/2006; 305:1-23. · 4.86 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: It has become clear that the autoreactive B cells are a part of the normal naïve B cell repertoire in the periphery, despite the fact that they undergo a series of checkpoints, which include receptor editing (revision), clonal deletion, and anergy. However, most of those B cells reactive against self antigen remain functionally naïve for autoantibody production by differential peripheral checkpoints. Therefore, the presence of autoreactive B cells does not always signify disease. Regulation of their activation and effector functions will determine the ultimate outcome. Although autoreactive B cell tolerance is well maintained in the healthy individual, the existence of pathogenic autoantibodies in autoimmune diseases indicates that these tolerogenic checkpoints are broken. Recent studies have demonstrated that autoreactive B cells are regulated by a composite of factors, such as genetic susceptibility and environmental triggers such as bacterial and viral infections as well as other immune cells. Interestingly, Toll-like receptors, previously considered as pattern-recognition receptors to detect and sense pathogens, may also have a potential to recognize self antigens and regulate autoreactive B cells for activation. Understanding the mechanisms of autoreactive B cell regulation and activation may help in identifying novel targets for the treatment of autoimmune diseases.
    Archivum Immunologiae et Therapiae Experimentalis 01/2007; 55(2):83-9. · 2.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: B lymphocyte stimulator (BLyS), also known as B cell-activating factor, is a key positive regulator of B cell homeostasis, and elevated levels of BLyS have been observed in systemic lupus erythematosus (SLE) patients. Given that anti-chromatin auto-antibodies are one of the hallmarks of SLE, we examined the role of BLyS and its receptors in the regulation of anti-chromatin B cells. We demonstrate that exogenous BLyS treatment leads to an increase in B cell numbers, particularly anti-chromatin B cells; yet, their localization in the spleen and auto-antibody production remain unaffected. We also examined transmembrane activator and CAML interactor (TACI), BLyS receptor 3 (BR3) and B cell maturation antigen expression on anti-chromatin B cells before and after receiving T cell help. Interestingly, in the absence of T cell help, TACI expression is greater on immature anti-chromatin B cells compared with immature Tg(-) B cells, whereas BR3 levels are comparable. After receiving T cell help, the anti-chromatin B cells that have differentiated into short-lived plasma cells no longer express BR3 but retain TACI. These data suggest a novel role for TACI in anti-chromatin B cell homeostasis and differentiation.
    International Immunology 05/2007; 19(4):465-75. · 3.14 Impact Factor

Full-text (2 Sources)

Available from
Nov 5, 2014