title: Polyclonal stimulation of resting B lymphocytes by antigen-specific T lymphocytes.
abstract: Resting B lymphocytes are activated, proliferate, and differentiate into antibody-secreting cells when cultured with long-term lines of major histocompatibility complex (MHC)-restricted, antigen-specific T cell in the presence of the antigen for which the T cells are specific. Under optimal conditions, essentially all B cells are activated and approximately 35% enter S phase in the absence of antigens for which the B cells are specific. Activation and proliferation are observed in cells from both normal mice and mice with the xid-determined immune defect. Highly purified B cells bearing Ia molecules for which the T cells are "cospecific" can present antigen to T cells with the resulting T cell stimulation leading to the activation and proliferation of the antigen-presenting B cells. However, B cells that do not bear Ia molecules for which the T cells are cospecific are also activated and proliferate if antigen and a source of antigen-presenting B cells or macrophage-rich cells of proper histocompatibility type are present. Thus, resting B cells, both normal and "xid", can be activated by non-MHC restricted factors without receptor cross-linkage. Experiments are presented that support the concept that local production and action of such unrestricted activating factors may be responsible for the MHC-restriction of T cell-B cell interaction seen in many circumstances.
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000502:physiology; D000921:Antibody-Producing Cells / Q000166:cytology / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D000939:Epitopes; D006183:H-2 Antigens / Q000235:genetics; D007075:Immunoglobulin M / Q000276:immunology; D007399:Interphase; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D010455:Peptides / Q000276:immunology; D011108:Polymers; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000939:Epitopes; D006183:H-2 Antigens; D007075:Immunoglobulin M; D010455:Peptides; D011108:Polymers; C020749:GAT