title: Immunoregulatory activity of T-cell subsets activated in human mixed lymphocyte reaction.
abstract: Unseparated human T cells or isolated OKT4+ and OKT8+ subsets were stimulated in allogeneic MLR and subsequently tested for their capacity to suppress fresh autologous responding cells in a second MLR. Contrary to the bulk of evidence regarding the immunoregulation of B-cell function, both OKT4+ and OKT8+ cells could be activated to form suppressors of the MLR and were equally radioresistant. An early peak of blastogenesis was observed when OKT4+ suppressors were used, and this event was completely radiosensitive. When the fresh responding cells were also fractionated into OKT4+ and OKT8+ subsets, no preference for suppressibility of either subset could be demonstrated, indicating that OKT4+ suppressors were acting directly and not through an inductive mechanism requiring OKT8+ effectors. It is suggested that when alloantigenic responses are involved, the human T-cell subsets defined by these monoclonal antibodies may be more accurately defined by the class of MHC antigen to which they respond than by their effector function.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D002469:Cell Separation; D006801:Humans; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal