-
[show abstract]
[hide abstract]
ABSTRACT: The relative contributions of B lymphocytes and plasma cells during allograft rejection remain unclear. Therefore, the effects of B cell depletion on acute cardiac rejection, chronic renal rejection, and skin graft rejection were compared using CD20 or CD19 mAbs. Both CD20 and CD19 mAbs effectively depleted mature B cells, and CD19 mAb treatment depleted plasmablasts and some plasma cells. B cell depletion did not affect acute cardiac allograft rejection, although CD19 mAb treatment prevented allograft-specific IgG production. Strikingly, CD19 mAb treatment significantly reduced renal allograft rejection and abrogated allograft-specific IgG development, whereas CD20 mAb treatment did not. By contrast, B cell depletion exacerbated skin allograft rejection and augmented the proliferation of adoptively transferred alloantigen-specific CD4(+) T cells, demonstrating that B cells can also negatively regulate allograft rejection. Thereby, B cells can either positively or negatively regulate allograft rejection depending on the nature of the allograft and the intensity of the rejection response. Moreover, CD19 mAb may represent a new approach for depleting both B cells and plasma cells to concomitantly impair T cell activation, inhibit the generation of new allograft-specific Abs, or reduce preexisting allograft-specific Ab levels in transplant patients.
The Journal of Immunology 02/2011; 186(4):2643-54. · 5.79 Impact Factor
-
Yohei Iwata,
Takashi Matsushita,
Mayuka Horikawa,
David J Dilillo,
Koichi Yanaba,
Guglielmo M Venturi,
Paul M Szabolcs,
Steven H Bernstein, Cynthia M Magro,
Armistead D Williams,
Russell P Hall,
E William St Clair,
Thomas F Tedder
[show abstract]
[hide abstract]
ABSTRACT: Regulatory B cells control inflammation and autoimmunity in mice, including the recently identified IL-10-competent B10 cell subset that represents 1% to 3% of spleen B cells. In this study, a comparable IL-10-competent B10 cell subset was characterized in human blood. B10 cells were functionally identified by their ability to express cytoplasmic IL-10 after 5 hours of ex vivo stimulation, whereas progenitor B10 (B10pro) cells required 48 hours of in vitro stimulation before they acquired the ability to express IL-10. B10 and B10pro cells represented 0.6% and approximately 5% of blood B cells, respectively. Ex vivo B10 and B10pro cells were predominantly found within the CD24(hi)CD27(+) B-cell subpopulation that was able to negatively regulate monocyte cytokine production through IL-10-dependent pathways during in vitro functional assays. Blood B10 cells were present in 91 patients with rheumatoid arthritis, systemic lupus erythematosus, primary Sjögren syndrome, autoimmune vesiculobullous skin disease, or multiple sclerosis, and were expanded in some cases as occurs in mice with autoimmune disease. Mean B10 + B10pro-cell frequencies were also significantly higher in patients with autoimmune disease compared with healthy controls. The characterization of human B10 cells will facilitate their identification and the study of their regulatory activities during human disease.
Blood 10/2010; 117(2):530-41. · 9.90 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Autoimmunity results from abnormal B- and T-cell recognition of self-antigens, which leads to autoantibody production in many cases. Autoantibodies produced by B-cell-derived plasma cells provide diagnostic markers for autoimmunity but also contribute significantly to disease pathogenesis. As discussed in this review, the therapeutic benefit of depleting B cells in mice and humans has refocused attention on B cells and their role in autoimmunity beyond autoantibody production. B cells specifically serve as cellular adjuvants for CD4(+) T-cell activation, while regulatory B cells, including those that produce interleukin-10 (B10 cells), function as negative regulators of inflammatory immune responses. The emerging picture is that B cells, autoantibodies, and T cells are all important components of abnormal immune responses that lead to tissue pathology unique to each autoimmune disease, with their relative contributions changing during disease progression. Autoimmune diseases where B-cell functions are closely correlated with disease activity include systemic lupus erythematosus, rheumatoid arthritis, scleroderma, type 1 diabetes, and multiple sclerosis. Understanding the overlapping roles of B cells as mediators of autoimmune disease will facilitate the development of more precisely directed therapies and combination therapies with broader clinical efficacy than current depletion strategies that remove all B cells.
Immunological Reviews 07/2008; 223:284-99. · 11.15 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Despite the demonstrated clinical efficacy of CD20 monoclonal antibody (mAb) for lymphoma therapy, the in vivo mechanisms of tumor depletion remain controversial and variable. To identify the molecular mechanisms responsible for lymphoma killing by CD20 mAb in a homologous system amenable to mechanistic studies and genetic manipulation, a mouse lymphoma model was developed using primary tumor cells from a C57BL/6 Emicro-cMyc transgenic mouse and mouse antimouse CD20 mAbs. CD20 mAb treatment of syngeneic mice with adoptively transferred lymphomas prevented tumor development or significantly prolonged mouse survival depending on tumor volume, mAb dose, and treatment timing. Cooperative FcgammaRIV, FcgammaRIII, and FcgammaRI interactions mediated optimal lymphoma depletion by CD20 mAb in vivo, whereas clodronate-mediated depletion of macrophages eliminated the therapeutic benefit of CD20 mAb. Although CD20 mAbs activated complement in vitro and in vivo, normal and malignant B-cell depletion was induced through C1q- and C3-independent mechanisms. Thus, the ability of CD20 mAbs to deplete malignant B cells in vivo required FcgammaR-dependent use of the innate mononuclear cell immune system. These findings allow for mechanism-based predictions of the biologic outcome of CD20 mAb therapy and treatment optimization.
Blood 06/2008; 112(4):1205-13. · 9.90 Impact Factor
