Regulatory interactions governing the proliferation of T cell subsets stimulated with pokeweed mitogen.
Serial phenotyping of human peripheral blood mononuclear cells (PBMC) cultured with pokeweed mitogen (PWM) demonstrated an excess of T8+ cells after stimulation. Preferential expansion of the T8+ cell compartment was a result of T8+ cell blast transformation while T4+ cells generated fewer blasts and tended to remain as small resting cells. When the proliferative behavior of T cell subsets in PWM-stimulated PBMC with physiologic proportions of T4+ and T8+ cells was compared with that of cultures depleted of T4+ or T8+ cells, two levels of regulation of proliferation were found: without T4+ cell help, T8+ cells were unable to divide; however, in the presence of T4+ cells, PWM-stimulated T8+ cells became potent feedback inhibitors of T4+ cell proliferation. The mechanism of suppression by PWM-activated T8+ cells of T4+ cell proliferation, not only to PWM, but also to tetanus toxoid, was pursued by measuring decreased interleukin 2 (IL2) recovery from cultures containing suppressors. Although passive absorption of IL2 by PWM-activated cells could contribute to the suppression of fresh proliferative responses, as shown directly with isolated T4+ cells induced by PWM to express IL2 receptors, a much more profound suppression was mediated by PWM-activated T8+ cells. The regulation of proliferative responses of helper and suppressor T cell subsets may determine the magnitude of their subsequent interactions and thus control the ultimate outcome of in vivo physiologic and pathologic immune responses.
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology; D002452:Cell Count; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D010641:Phenotype; D011043:Pokeweed Mitogens / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D007376:Interleukin-2; D011043:Pokeweed Mitogens