title: Activation of helper T cells for B lymphocytes in primary mixed lymphocyte cultures.
abstract: Normal B10.BR (H-2k, C57B1/6 background) spleen cells, enriched in primary mixed lymphocyte culture (MLC) for antigens of C3H/Tif mice (H-2k, C3H background), induced normal C3H/Tif but not B10.BR B lymphocytes to proliferate and produce Ig. In contrast, normal B10.BR spleen cells enriched in parallel B10.BR anti-C57B1/6 (H-2b) MLC were not able to activate either B10.BR or C57B1/6 B lymphocytes. However, normal B10.BR spleen cells depleted of Lyt2+ cells before initiation of the MLC, and subsequently enriched either for C3H/Tif or C57B1/6 antigens, activated B lymphocytes of the respective mouse strains specifically and equally well. These experiments show that primary MLC gives rise to effector T helper cells that, on recognition of specific alloantigens, activate normal B lymphocytes of the 'stimulator' strain. In response to major histocompatibility complex (MHC) alloantigens, this help is not revealed because of interference by Lyt 2+ lymphocytes. MHC-reactive T helper cells for B lymphocytes, however, participate in these reactions and constitute the predominant population in long-term cultures that are maintained by consecutive in vitro restimulations.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D000939:Epitopes; D006183:H-2 Antigens / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008805:Mice, Inbred A; D008806:Mice, Inbred AKR; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008811:Mice, Inbred DBA; D008912:Minor Histocompatibility Loci; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D000939:Epitopes; D006183:H-2 Antigens; D000949:Histocompatibility Antigens Class II