title: Functions of purified L3T4+ and Lyt-2+ cells in vitro and in vivo.
abstract: The expression of L3T4 and Lyt-2 cell surface molecules separates T cells into two broad, non-overlapping subsets: typical T helper cells are L3T4+ Lyt-2- whereas most T killer cells and their precursors are L3T4- Lyt-2+. This review compares highly purified populations of unprimed L3T4+ and Lyt-2+ cells for their capacity to respond to class I vs. class II H-2 alloantigens. Various parameters are considered, including generation of mixed lymphocyte reactions (MLR) and cell mediated lympholysis (CML) in vitro, proliferative responses in irradiated mice, graft-versus-host reactions and skin allograft rejection. In all of these assays the two T cell subsets exhibit marked specificity in their response to H-2 alloantigens, L3T4+ cells responding only to class II and not class I differences and Lyt-2+ cells showing reciprocal specificity. Contrary to current dogma, the bulk of the evidence suggests that primary responses of Lyt-2+ cells do not depend on exogenous help provided by other T cells.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000032:analysis*; D002478:Cells, Cultured; D006084:Graft Rejection; D006086:Graft vs Host Disease; D006183:H-2 Antigens / Q000032:analysis; D006801:Humans; D008213:Lymphocyte Activation / Q000528:radiation effects; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D009154:Mutation; D016038:Skin Transplantation; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology* / Q000528:radiation effects
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D006183:H-2 Antigens