全身性強皮症におけるNK細胞の機能と活性化

取得学位 : 博士（医学）, 学位授与番号 : 医博甲第1768号 , 学位授与年月日 : 平成18年3月22日, 学位授与大学 : 金沢大

Regulatory B Cells (B10 cells) and Regulatory T Cells Have Independent Roles in Controlling EAE Initiation and Late-Phase Immunopathogenesis

Experimental autoimmune encephalomyelitis (EAE) is a T lymphocyte-mediated autoimmune disease of the CNS. Significant roles for B cells and a rare IL-10-producing CD1dhighCD5+ regulatory B cell subset (B10 cells) have been identified during the initiation and progression of EAE. Whether and how the regulatory functions of B10 cells and FoxP3+ T regulatory cells (Tregs) overlap or influence EAE immunopathogenesis independently has remained unanswered. This study demonstrates that the number of endogenous or adoptively transferred B10 cells directly influenced EAE pathogenesis through their production of IL-10. B10 cell numbers expanded quickly within the spleen, but not CNS following myelin oligodendrocyte glycoprotein35-55 immunization, which paralleled B10 cell regulation of disease initiation. The adoptive transfer of myelin oligodendrocyte glycoprotein33-35-sensitized B10 cells into wild-type mice reduced EAE initiation dramatically. However, B10 cells did not suppress ongoing EAE disease. Rather, Treg numbers expanded significantly within the CNS during disease progression, which paralleled their negative regulation of late-phase disease. Likewise, the preferential depletion of B10 cells in vivo during disease initiation enhanced EAE pathogenesis, whereas Treg depletion enhanced late-phase disease. B10 cells did not regulate T cell proliferation during in vitro assays, but significantly altered CD4+ T cell IFN-γ and TNF-α production. Furthermore, B10 cells downregulated the ability of dendritic cells to act as APCs and thereby indirectly modulated T cell proliferation. Thus, B10 cells predominantly control disease initiation, whereas Tregs reciprocally inhibit late-phase disease, with overlapping B10 cell and Treg functions shaping the normal course of EAE immunopathogenesis. Copyright © 2010 by The American Association of Immunologists, Inc

Elevated Serum BAFF Levels in Patients with Localized Scleroderma in contrast to other organ-specific autoimmune diseases

Serum levels of B-cell activating factor belonging to the tumor necrosis factor family (BAFF), a potent B-cell survival factor, are elevated in patients with systemic autoimmune diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis and systemic sclerosis (SSc). The objective of this study was to determine serum BAFF levels and relate the results to the clinical features in patients with organ-specific autoimmune diseases of the skin, such as localized scleroderma and autoimmune bullous diseases. Serum BAFF levels were examined by enzyme-linked immunosorbent assay in 44 patients with localized scleroderma, 20 with pemphigus vulgaris/pemphigus foliaceus, 20 with bullous pemphigoid and 30 healthy controls. Twenty patients with SSc and 20 with SLE were also examined as disease controls. Serum BAFF levels were elevated in localized scleroderma patients compared with healthy controls. Concerning localized scleroderma subgroups, patients with generalized morphea, the severest form of localized scleroderma, had higher serum BAFF levels than linear scleroderma or morphea patients. The BAFF levels of generalized morphea were comparable with those of SSc or SLE. Furthermore, serum BAFF levels correlated positively with antihistone antibody levels and the severity of skin lesion as well as the number of skin lesions. By contrast, serum BAFF levels were not significantly elevated in patients with pemphigus or pemphigoid. These results suggest that BAFF may be contributing to autoimmunity and disease development in localized scleroderma. © 2007 The Authors Journal compilation © 2007 Blackwell Munksgaard

Regulatory B Cell (B10 Cell) Expansion during Listeria Infection Governs Innate and Cellular Immune Responses in Mice

Pathogens use numerous methods to subvert host immune responses, including the modulation of host IL-10 production by diverse cell types. However, the B cell sources of IL-10 and their overall influence on innate and cellular immune responses have not been well characterized during infections. Using Listeria as a model pathogen, infection drove the acute expansion of a small subset of regulatory B cells (B10 cells) that potently suppress inflammation and autoimmunity through the production of IL-10. Unexpectedly, spleen bacteria loads were 92–97% lower in B10 cell-deficient CD19−/− mice, in mice depleted of mature B cells, and in mice treated with CD22 mAb to preferentially deplete B10 cells before infection. By contrast, the adoptive transfer of wild type B10 cells reduced bacterial clearance by 38-fold in CD19−/− mice through IL-10-dependent pathways. B10 cell depletion using CD22 mAb significantly enhanced macrophage phagocytosis of Listeria and their production of IFN-γ, TNF-α, and nitric oxide ex vivo. Accelerated bacteria clearance following B10 cell depletion significantly reduced Ag-specific CD4+ T cell proliferation and cytokine production, but did not alter CD8+ T cell responses. B10 cell regulatory function during innate immune responses was nonetheless dependent on cognate interactions with CD4+ T cells since B10 cells deficient in IL-10, MHC-II or IL-21 receptor expression did not influence Listeria clearance. Thus, Listeria manipulates immune responses through a strategy of immune evasion that involves the preferential expansion of endogenous B10 cells that regulate the magnitude and duration of both innate and cellular immune responses

Blockade of CD40/CD40 ligand interactions attenuates skin fibrosis and autoimmunity in the tight-skin mouse.

OBJECTIVE: To assess the association of CD40/CD40 ligand (CD40L) interactions with the development of skin fibrosis and autoimmunity in tight-skin (TSK/+) mouse, which is a mouse model for human systemic sclerosis. METHODS: Newly born TSK/+ mice were treated with murine anti-CD40L monoclonal antibody (100 microg intraperitoneally weekly). Hypodermal thickness of 8-week-old female mice (defined as the thickness of a subcutaneous loose connective tissue layer beneath the panniculus carnosus) was measured under a light microscope. All skin sections were taken from the para-midline, upper back region. Serum anti-topoisomerase I autoantibody levels, serum immunoglobulin levels and plasma soluble CD40L levels were determined by enzyme-linked immunosorbent assay. For analysis of lymphocyte surface molecules, single cell suspensions of lymphocytes were stained by monoclonal antibodies. Proliferation of TSK/+ B cells and fibroblasts to anti-CD40 antibodies was assessed by the uptake of [3H]-labelled thymidine and bromodeoxyuridine, respectively. RESULTS: The blockade of CD40/CD40L interactions by anti-CD40L monoclonal antibody significantly reduced cutaneous fibrosis (65%) and anti-topoisomerase I autoantibody in TSK/+ mice. Anti-CD40L monoclonal antibody also normalised B lymphocyte abnormal activation in TSK/+ mice, demonstrated by hyper-gamma-globulinaemia. Furthermore, augmented CD40/CD40L interactions in TSK/+ mice were suggested by upregulated expression of CD40L on CD4(+) T cells, elevated plasma soluble CD40L levels. The hyperresponsiveness to CD40 stimulation was also observed in TSK/+ B cells and fibroblasts. CONCLUSIONS: Cutaneous fibrosis and autoimmunity in TSK/+ mice are closely correlated with CD40/CD40L interactions