title: Regulatory mechanisms in the mixed lymphocyte reaction: evidence for the requirement of two T cells to interact in the generation of effective suppression.
abstract: The cellular requirements for suppression of a mixed lymphocyte reaction (MLR) by in vivo alloantigen-activated spleen cells were investigated. We found that the suppression was mitomycin-resistant at days 3 and 5 after antigen injection. By contrast, it was radiation-sensitive on day 3 but not on day 5. Cell fractionation studies using a plate separation technique monitored by flow microfluorometry were performed. We found that neither purified Lyt-2- cells nor purified Lyt-2+ cells independently could suppress an MLR. By contrast, the reconstituted T population was still suppressive. It also was found that culture supernatant factors from allogeneically in vitro restimulated Lyt-2- cells could suppress an MLR if Lyt-2+ cells were present in the responding population. These data obtained by positive selection and reconstitution show that at least two surface immunoglobulin-negative cells interact for the generation of effective MLR suppression. The possibility that we are dealing with a suppressor-inducer, suppressor-effector system is discussed.
mesh_terms: D000042:Absorption; D000818:Animals; D000950:Antigens, Ly; D005260:Female; D007114:Immunization; D007519:Isoantigens / Q000008:administration & dosage; D008213:Lymphocyte Activation / Q000528:radiation effects; D008211:Lymphocyte Cooperation; D007959:Lymphocyte Culture Test, Mixed; D008222:Lymphokines / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D016685:Mitomycin; D008937:Mitomycins; D013491:Suppressor Factors, Immunologic; D050378:T-Lymphocytes, Regulatory / Q000145:classification / Q000276:immunology* / Q000528:radiation effects
chemical_list: D000950:Antigens, Ly; D007519:Isoantigens; D008222:Lymphokines; D008937:Mitomycins; D013491:Suppressor Factors, Immunologic; D016685:Mitomycin