CD4+ T-cell population mediates development of inflammatory bowel disease in T-cell receptor α chain-deficient mice

Abstract

Background and Aims: Increase of T cells expressing CD4 and T-cell receptor (TCR) α β+ (B(dim)) was observed in the mucosal and peripheral lymphoid tissues of TCR α(-/-) mice with inflammatory bowel disease (IBD). The aim of this study was to characterize the CD4+ TCR β+ T cells. Methods: Cytokine production, TCR Vβ usage, and helper function for Peyer's patch B cells by the CD4+ TCR α-β+ T cells were assessed. Results: The CD4+ TCR α-β+ T cells purified from mesenteric lymph nodes and lamina propria of the intestine of IBD mice exclusively produced inteleukin 4, used selected subsets (Vβ6, Vβ8, Vβ14, and Vβ15) of TCR, and massively proliferated after stimulation with staphylococcal enterotoxin B. Addition of the CD4+ TCR α-β+ T cells to Peyer's patch B-cell cultures markedly enhanced immunoglobulin (Ig) A, IgG, and IgM antibody responses. Furthermore, depletion of the TCR α-β+ T cells with monoclonal antibody against TCR β chain completely suppressed the onset of IBD and polyclonal B-cell activation in the TCR α(-/-) mice. Conclusions: These findings suggest the CD4+ TCR α-β+ T cells-mediated development of IBD in TCR α(-/-) mice.