title: CD28 delivers a costimulatory signal involved in antigen-specific IL-2 production by human T cells.
abstract: CD4+ T cells require two signals to produce maximal amounts of IL-2, i.e., TCR occupancy and an unidentified APC-derived costimulus. Here we show that this costimulatory signal can be delivered by the T cell molecule CD28. An agonistic anti-CD28 mAb, but not IL-1 and/or IL-6, stimulated T cell proliferation by tetanus toxoid-specific T cells cultured with Ag-pulsed, costimulation-deficient APC. Furthermore, the ability of B cell tumor lines to provide costimulatory signals to purified T cells correlated well with expression of the CD28 ligand B7/BB-1. Finally, like anti-CD28 mAb, autologous human APC appeared to stimulate a cyclosporine A-resistant pathway of T cell activation. Together, these results suggest that the two signals required for IL-2 production by CD4+ T cells can be transduced by the TCR and CD28.
authors.affiliation: Department of Microbiology, University of Minnesota Medical School, Minneapolis 55455.
authors.forename: M K
authors.initials: MK
authors.lastname: Jenkins
authors.forename: P S
authors.initials: PS
authors.lastname: Taylor
authors.forename: S D
authors.initials: SD
authors.lastname: Norton
authors.forename: K B
authors.initials: KB
authors.lastname: Urdahl
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000502:physiology; D015703:Antigens, CD / Q000502:physiology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology / Q000502:physiology*; D000954:Antigens, Surface / Q000502:physiology; D018122:B7-1 Antigen; D018106:CD28 Antigens; D017252:CD3 Complex; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis*; D008213:Lymphocyte Activation; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism*; D013745:Tetanus Toxoid / Q000276:immunology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D018122:B7-1 Antigen; D018106:CD28 Antigens; D017252:CD3 Complex; D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell; D013745:Tetanus Toxoid; D013755:Tetradecanoylphorbol Acetate