title: Specific binding of alloantigens to T cells activated in the mixed lymphocyte reaction.
abstract: Immunoglobulin (Ig) is present on a large fraction of T cells from unfractionated lymphocytes activated by in vitro stimulation with H-2-incompatible cells (mixed lymphocyte reaction [MLR]). Removal of bursa equivalent-derived (B) cells from the responder cell population before mixed culture, by filtration through nylon wool columns, reduces the percentage of Ig-bearing responder T blasts to background levels. Thus, Ig on the T blast is probably of B cell origin. A large fraction of T blasts activated against the stimulator cells. This staining occurs with "early" and hyperimmune alloantisera, including the 7S fraction of the latter. B-depleted responder cells were activated against a mixture of two different stimulator cells and the resulting T blasts stained with different concentrations of sera directed either against one or both stimulator cells. We obtained results which strongly suggest that most or all responder T blasts stain with only one antistimulator serum. When antisera directed against different segments of the H-2 complex of the stimulator cells were used, it seemed that most responder T cells only bound antibody directed against a single segment. We propose that T cells activated in MLR carry stimulator alloantigens on their surface, and that this is due to specific antigen binding, not requiring the presence of B-cell-derived antibody. These histocompatibility antigen-binding T blasts can be detected by appropriate antistimulator alloantibodies.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D001666:Binding Sites, Antibody; D002462:Cell Membrane / Q000276:immunology; D000939:Epitopes; D005260:Female; D006680:HLA Antigens; D006649:Histocompatibility Antigens; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D007518:Isoantibodies; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008297:Male; D051379:Mice; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000939:Epitopes; D006680:HLA Antigens; D006649:Histocompatibility Antigens; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007518:Isoantibodies