title: Influence of immunoglobulin-dependent T cells on antibody class switching.
abstract: Normal and B cell-deficient, carrier-primed mice were irradiated and were adoptively transferred with B cells to evaluate the role of putative Ig- and B cell-dependent T cells in anti-hapten antibody responses. The response was analyzed by using the splenic focus assay, which allowed us to examine the frequency of responding B cells and the production of multiple isotypes by single precursor B cells. This analysis revealed that both primary and secondary B cells were activated at higher frequency in the spleens of normal recipients, and production of isotypes other than IgM and IgG1 was enhanced in normal recipients as compared with anti-mu-treated recipients. Both changes could be restored to control levels by co-transfer of T cells from normal donors primed with an unrelated carrier, provided the free carrier was added to the assay culture. These results are consistent with a role for Ig or B cell-dependent helper T cells in the optimal activation and the resulting isotype expression of both primary and secondary B cells.
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000096:biosynthesis; D001402:B-Lymphocytes / Q000378:metabolism; D002999:Clone Cells / Q000378:metabolism; D007108:Immune Tolerance; D007126:Immunoglobulin Allotypes / Q000096:biosynthesis* / Q000145:classification; D007075:Immunoglobulin M / Q000096:biosynthesis / Q000276:immunology / Q000502:physiology*; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D007126:Immunoglobulin Allotypes; D007075:Immunoglobulin M; C044203:anti-IgM