title: Requirements for the induction of allospecific CD8+ suppressor T cells in the rat primary mixed lymphocyte response. CD4+, CD45R+ T cells, or supernatant factor.
abstract: We examined the requirements for the induction of the MLR-generated allospecific CD8+ suppressor T cells in the rat. Depleting the responder population of CD4+ T cells before initiating the primary MLR abrogates the generation of day-5 CD8+ T suppressor effectors. Readdition of at least 10% CD4+ T cells to the CD4+ depleted primary MLR reconstitutes suppressor cell generation. Using the anti-CD45R monoclonal antibody OX22, we also show that the T suppressor inducer cells are CD4+ CD45R+. Using a dual chamber Transwell culture system, which allows cells to be co-incubated without direct cell-to-cell contact, we show that a soluble factor/s, produced during the course of the primary MLR, is capable of inducing naive CD8+ T cells to become suppressor effectors but only when these CD8 T cells are in direct contact with allogeneic stimulators. Allospecificity is conferred by the stimulator cells and not by the suppressor-inducer factor. The supernatant of day-5 primary MLR is also capable of inducing antigen-specific suppressor effectors from naive CD8+ T cells, and also only in the presence of allogeneic stimulator cells. Recombinant human IL-2, in doses that are up to five times the amount present in the supernatant cultures, is unable to induce suppressor-effector cells from naive CD8+ T cells. We conclude that, to become allospecific suppressor effectors, naive CD8+ T cells require contact with allogeneic stimulator cells and either CD4+ CD45R+ suppressor inducer cells or suppressor inducer factor/s produced during the course of the primary MLR.
authors.affiliation: Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: A H
authors.initials: AH
authors.lastname: Frankel
authors.forename: M H
authors.initials: MH
authors.lastname: Sayegh
authors.forename: D M
authors.initials: DM
authors.lastname: Rothstein
authors.forename: E L
authors.initials: EL
authors.lastname: Milford
authors.forename: C B
authors.initials: CB
authors.lastname: Carpenter
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000941:Antigens; D000943:Antigens, Differentiation; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D006649:Histocompatibility Antigens; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000494:pharmacology; D017493:Leukocyte Common Antigens; D007959:Lymphocyte Culture Test, Mixed; D051381:Rats; D011919:Rats, Inbred Strains; D011994:Recombinant Proteins / Q000494:pharmacology; D013491:Suppressor Factors, Immunologic / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000941:Antigens; D000943:Antigens, Differentiation; D006649:Histocompatibility Antigens; D007376:Interleukin-2; D011994:Recombinant Proteins; D013491:Suppressor Factors, Immunologic; D017493:Leukocyte Common Antigens