CD20 antibody depletion of B lymphocytes effectively ameliorates multiple T cell-mediated autoimmune diseases through mechanisms that remain unclear. To address this, a mouse CD20 antibody that depletes >95% of mature B cells in mice with otherwise intact immune systems was used to assess the role of B cells in CD4 ؉ and CD8 ؉ T cell activation and expansion in vivo. B cell depletion had no direct effect on T cell subsets or the activation status of CD4 ؉ and CD8 ؉ T cells in naive mice. However, B cell depletion impaired CD4 ؉ T cell activation and clonal expansion in response to protein antigens and pathogen challenge, whereas CD8 ؉ T cell activation was not affected. In vivo dendritic cell ablation, along with CD20 immunotherapy, revealed that optimal antigen-specific CD4 ؉ T cell priming required both B cells and dendritic cells. Most importantly, B cell depletion inhibited antigen-specific CD4 ؉ T cell expansion in both collagen-induced arthritis and autoimmune diabetes mouse models. These results provide direct evidence that B cells contribute to T cell activation and expansion in vivo and offer insights into the mechanism of action for B cell depletion therapy in the treatment of autoimmunity.autoimmune disease ͉ B lymphocyte ͉ immunotherapy ͉ antigen presentation
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.