title: Similar co-stimulation requirements of CD4+ and CD8+ primary T helper cells: role of IL-1 and IL-6 in inducing IL-2 secretion and subsequent proliferation.
abstract: Primary murine CD4+ and CD8+ T helper (Th) cells provide help for various immune responses by secreting lymphokines which activate effector cells. The purpose of the present study was to investigate the co-stimulatory signals that, together with T cell receptor (TCR) cross-linking, induce phenotypically distinct primary Th cells to secrete IL-2 and proliferate. We isolated highly purified populations of primary CD4+ or CD8+ T cells and stimulated them in vitro with platebound anti-CD3 mAb. TCR cross-linking by anti-CD3 mAb induced both IL-2 receptor expression and responsiveness to exogenous IL-2, but was not sufficient to induce either IL-2 secretion or T cell proliferation. Rather, for both CD4+ and CD8+ primary Th cells, IL-2 secretion and proliferation required both TCR cross-linking and antigen presenting cell (APC)-derived co-stimulatory signals. Based on G-10 adherence and sensitivity to gamma-irradiation, the APC populations able to induce primary CD4+ Th cells and primary CD8+ Th cells to secrete IL-2 were indistinguishable. In addition, we found that either IL-1 or IL-6 could replace the requirement for APC-derived co-stimulatory signals for IL-2 secretion and proliferation by both primary CD4+ Th cells and primary CD8+ Th cells. Thus, the present study has examined and compared the co-stimulatory requirements of rigorously purified subsets of IL-2-secreting primary CD4+ and primary CD8+ T cells.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
authors.forename: P H
authors.initials: PH
authors.lastname: Stein
authors.forename: A
authors.initials: A
authors.lastname: Singer
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D015704:CD4 Antigens; D016827:CD8 Antigens; D003432:Cross-Linking Reagents; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000494:pharmacology; D007376:Interleukin-2 / Q000378:metabolism; D015850:Interleukin-6 / Q000494:pharmacology; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D015704:CD4 Antigens; D016827:CD8 Antigens; D003432:Cross-Linking Reagents; D007375:Interleukin-1; D007376:Interleukin-2; D015850:Interleukin-6; D011948:Receptors, Antigen, T-Cell