title: The collaborative phenotype of secondary B cells is determined by T lymphocytes during in vivo immunization.
abstract: Previous studies have demonstrated that the B cells in immune and nonimmune mice manifest different major histocompatibility complex (MHC) collaborative phenotypes with antigen-specific T cells. Immune, or secondary B cells require syngeneic-like MHC recognition by collaborating T cells, and in its absence fail to be stimulated. Primary B cells manifest a much less stringent requisite for MHC recognition by T cells, and under conditions in which secondary B cells fail to be stimulated, primary B cells are stimulated to secrete IgM antibody. Experiments were conducted to determine whether the acquisition of the secondary B cells' MHC collaborative phenotype was dependent on the presence of T cells during in vivo immunization. B cell populations from T dependently and T independently immunized conventional BALB/c and athymic BALB/c nu/nu mice were compared in their ability to collaborate with allogeneic T cells. Although antigen alone promotes the differentiation of several secondary B cell characteristics, including an increase in the frequency of antigen-specific B cells and a preference for IgG1 antibody synthesis in vitro, the acquisition of the secondary B cells' MHC collaborative phenotype was dependent on the presence of T cells during in vivo immunization. B cell populations from T dependently and T independently immunized conventional BALB/c and athymic BALB/c nu/nu mice were compared in their ability to collaborate with allogeneic T cells. Although antigen alone promotes the differentiation of several secondary B cell characteristics, including an increase in the frequency of antigen-specific B cells and a preference of IgG1 antibody synthesis in vitro, the acquisition of the secondary B cells' MHC collaborative phenotype was found to be dependent on the presence of T cells during in vivo immunization. Thus, the restriction imposed on T cell-B-cell-collaborative interactions in secondary humoral immune responses appears to be the result of T dependent antigen-driven events.
mesh_terms: D000818:Animals; D000941:Antigens / Q000008:administration & dosage*; D001402:B-Lymphocytes / Q000276:immunology*; D002417:Cattle; D004136:Dinitrobenzenes / Q000276:immunology; D000939:Epitopes; D005362:Ficoll / Q000276:immunology; D006183:H-2 Antigens / Q000276:immunology; D006433:Hemocyanins / Q000276:immunology; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D008211:Lymphocyte Cooperation; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010641:Phenotype; D011817:Rabbits; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000941:Antigens; D004136:Dinitrobenzenes; D000939:Epitopes; D006183:H-2 Antigens; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D005362:Ficoll; D006433:Hemocyanins