sgp-60, a signal-transducing glycoprotein concerned with T cell activation through the T cell receptor/CD3 complex.
T cell activation depends not only on the expression of a TCR, but also on that of accessory molecules that function in cell-cell adhesion and/or signal transduction. The subject of this report is the biochemical and functional characterization of what appears to be a novel murine lymphocyte cell surface antigen, provisionally termed sgp-60. Extensive, higher-order cross-linking of this glycoprotein with an anti-sgp-60 mAb and a second-step antibody reagent results in the activation of resting CD4+ T cells in the presence of a second signal. Monovalent or bivalent engagement of sgp-60 by the anti-sgp-60 antibody results in profound and direct inhibition of anti-CD3- or Con A-driven T cell activation, whereas alternative T cell activation via the phosphatidylinositol-linked proteins Thy-1 and TAP/Ly-6A is not affected. These findings raise the possibility that the sgp-60 molecule may be specifically involved in signal transduction through the TCR/CD3 complex and thus point to an important physiologic role for this protein in CD4+ T cells.
Reiser
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Department of Pathology, Harvard Medical School, Boston, MA 02115.
D000818:Animals; D000911:Antibodies, Monoclonal; D000938:Antigen-Presenting Cells / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis / Q000502:physiology*; D000950:Antigens, Ly / Q000502:physiology; D000954:Antigens, Surface / Q000502:physiology*; D018801:CD2 Antigens; D017252:CD3 Complex; D006023:Glycoproteins / Q000032:analysis / Q000502:physiology*; D006031:Glycosylation; D007376:Interleukin-2 / Q000494:pharmacology; D008213:Lymphocyte Activation; D046911:Macromolecular Substances; D051379:Mice; D008970:Molecular Weight; D010716:Phosphatidylinositols / Q000502:physiology; D011233:Precipitin Tests; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D011971:Receptors, Immunologic / Q000032:analysis; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000502:physiology*; D018800:Thy-1 Antigens
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly; D000954:Antigens, Surface; D018801:CD2 Antigens; D017252:CD3 Complex; D006023:Glycoproteins; D007376:Interleukin-2; D046911:Macromolecular Substances; D010716:Phosphatidylinositols; D011948:Receptors, Antigen, T-Cell; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D018800:Thy-1 Antigens