title: Regulation of human cytotoxic T-lymphocyte responses by a soluble suppressor factor.
abstract: We describe some aspects of the biology of a suppressor factor (SF) secreted by actively metabolizing and dividing alloantigen-primed T cells which functions by regulating human cytotoxic T-lymphocyte (CTL) activation. The SF functions most effectively during the first 24 hr of CTL activation, while it does not function at the CTL effector stage. Both T cells and adherent cells are capable of absorbing out the biological activity from suppressor factor supernatants. Experiments demonstrated that either fresh adherent cells or the addition of interleukin 2 (IL-2) into the test system could reverse the effects of the SF on CTL activation. These data suggest that the SF could be acting by either indirectly restricting IL-2 availability to proliferating CTLs by limiting adherent cell interleukin 1 (IL-1) secretion or, alternatively, SF acting directly on the IL-2-producing T cells.
mesh_terms: D001386:Azides / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic; D006801:Humans; D007376:Interleukin-2 / Q000276:immunology; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000276:immunology*; D016685:Mitomycin; D008937:Mitomycins / Q000494:pharmacology; D013491:Suppressor Factors, Immunologic; D013601:T-Lymphocytes / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D001386:Azides; D007376:Interleukin-2; D008222:Lymphokines; D008937:Mitomycins; D013491:Suppressor Factors, Immunologic; D016685:Mitomycin