title: Thy-1-mediated T-cell activation requires co-expression of CD3/Ti complex.
abstract: In addition to monoclonal antibodies against the CD3 (T3)-T-cell antigen receptor (CD3/Ti) complex, several other monoclonals directed towards distinct cell surface structures on human (CD2 (T11) and Tp44) and murine (Thy-1, TAP, and Ly-6) T lymphocytes are capable of activating T cells. It has been proposed that such structures may function as alternative pathways of stimulation. To examine directly whether any relationship exists between Thy-1-dependent activation phenomena and T-cell activation mediated through the CD3/Ti complex, we have transfected several CD3/Ti- variants of the human T-cell line Jurkat with the murine Thy-1.2 gene. Our data indicate that in CD3/Ti-, Thy-1.2+ transfectants, monoclonal antibodies against Thy-1.2 can induce a rise in cytoplasmic free calcium ([Ca2+]i), but fail to stimulate interleukin-2 (IL-2) production. The only defect in these variant cell lines responsible for the inability to produce IL-2 in response to Thy-1 stimulation was in the expression of the CD3/Ti complex, because replacement of defective Ti alpha- or beta-chain genes reconstributed both surface expression of CD3/Ti and responsiveness to Thy-1 in the IL-2 production assay.
mesh_terms: D000936:Antigen-Antibody Complex / Q000276:immunology; D000001:Calcimycin / Q000494:pharmacology; D002460:Cell Line; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D007518:Isoantibodies; D008213:Lymphocyte Activation; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000936:Antigen-Antibody Complex; D007376:Interleukin-2; D007518:Isoantibodies; D011948:Receptors, Antigen, T-Cell; C035678:anti-Thy antibody; D000001:Calcimycin; D013755:Tetradecanoylphorbol Acetate