title: Interleukin 2 regulates the expression of Tac antigen on peripheral blood T lymphocytes.
abstract: We investigated the effect of OKT3 antibody and interleukin 2 (IL-2) on Tac antigen expression and the proliferation of human peripheral blood mononuclear leukocytes. OKT3 monoclonal antibody at low, nonmitogenic concentrations (25 pg/ml) or IL-2 alone at optimal concentrations (20 U/ml) did not induce IL-2 receptor expression, as measured by Tac antibody or by T cell proliferation. However, costimulation with these concentrations of OKT3 antibody and IL-2 led to Tac antigen expression and T cell proliferation. These data suggest that the T cells are activated in two steps: OKT3 antibody at 25 pg/ml does not induce Tac antigen expression, but preactivates T cells to become responsive to IL-2. The addition of exogenous IL-2 then leads to expression of the IL-2 receptor, as recognized by Tac antibody, and to subsequent proliferation.
mesh_terms: D000911:Antibodies, Monoclonal / Q000502:physiology; D000954:Antigens, Surface / Q000032:analysis* / Q000276:immunology; D004247:DNA / Q000032:analysis / Q000096:biosynthesis; D005455:Fluorescent Antibody Technique; D006801:Humans; D007371:Interferon-gamma / Q000502:physiology; D007376:Interleukin-2 / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology*; D007700:Kinetics; D008213:Lymphocyte Activation; D008262:Macrophage Activation; D016685:Mitomycin; D008937:Mitomycins / Q000494:pharmacology; D014176:Protein Biosynthesis; D013601:T-Lymphocytes / Q000032:analysis / Q000276:immunology*; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D007376:Interleukin-2; D008937:Mitomycins; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D016685:Mitomycin; D007371:Interferon-gamma; D004247:DNA