Gene-targeted B-deficient mice reveal a critical role for B cells in the CD4 T cell response.
The role of B cells in promoting T cell responses is still controversial. In this study, we use JHD mice which have a targeted mutation in the JH gene and are thus rendered deficient in B cells to address this issue. We show here that immunization of JHD mice with soluble antigen fails to prime CD4 T cells, for either clonal expansion or delivery of immunological help for antibody responses. This lack of CD4 T cell priming in JHD mice corresponds to a 3- to 9-fold lower co-stimulatory activity of antigen-presenting cells (APC) from the JHD mice, as measured by anti-CD3-induced proliferative responses of CD4 T cells. This in turn is due to a defect of APC from JHD mice in response to T cell-mediated induction of co-stimulatory activity. As the development of macrophages and dendritic cells is unaffected in the JHD mice, our results demonstrate that B cells play a critical role in CD4 T cell priming, possibly by delivering a critical co-stimulatory activity for clonal expansion of CD4 T cells.
D000818:Animals; D000938:Antigen-Presenting Cells / Q000502:physiology; D001402:B-Lymphocytes / Q000276:immunology* / Q000502:physiology; D017252:CD3 Complex / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002450:Cell Communication / Q000235:genetics* / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology; D017353:Gene Deletion; D008213:Lymphocyte Activation / Q000235:genetics; D018655:Lymphocyte Count; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008817:Mice, Mutant Strains; D013154:Spleen / Q000166:cytology
D017252:CD3 Complex