title: Human T cell activation. II. A new activation pathway used by a major T cell population via a disulfide-bonded dimer of a 44 kilodalton polypeptide (9.3 antigen).
abstract: In previous studies (17-21), monoclonal antibody (mAb) 9.3 has been shown to react with a major population of human T cells, which include T4+ helper/inducer T cells and T8+ cytotoxic T cells. In this investigation, mAb 9.3 was shown to precipitate a disulfide-bonded dimer of a 44 kD polypeptide. Comodulation experiments showed that this molecule is not linked to T3/Ti or T11 antigens. mAb 9.3 was capable of inducing T cell proliferation in the presence of 12-o-tetradecanoyl phorbol-13-acetate (TPA). This effect was monocyte-independent. T cell activation with mAb 9.3 and TPA was associated with increases in interleukin 2(IL-2) receptor expression and IL-2 secretion. mAb 9.3 did not activate T cells, even with the addition of IL-1 or IL-2. Modulation of the T3 complex did not abolish mAb 9.3-induced T cell proliferation in the presence of TPA. These results suggest that the 9.3 antigen may serve as a receptor for an activation pathway restricted to a T cell subset.
authors.forename: T
authors.initials: T
authors.lastname: Hara
authors.forename: S M
authors.initials: SM
authors.lastname: Fu
authors.forename: J A
authors.initials: JA
authors.lastname: Hansen
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology*; D017252:CD3 Complex; D006801:Humans; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000276:immunology; D007376:Interleukin-2 / Q000276:immunology; D008213:Lymphocyte Activation; D011487:Protein Conformation; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D011971:Receptors, Immunologic; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D017252:CD3 Complex; D007375:Interleukin-1; D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell; D011971:Receptors, Immunologic; D013755:Tetradecanoylphorbol Acetate