title: Granzyme A secretion by normal activated Lyt-2+ and L3T4+ T cells in response to antigenic stimulation.
abstract: Granzyme A is a serine esterase initially isolated from cytoplasmic granules of cytolytic T cell lines (Masson, D. et al., EMBO J. 1986. 5: 1595). Among normal T lymphocytes activated by allogeneic stimulation it is found in both Lyt-2+ and L3T4+ subsets in comparable amounts. Here we show that normal alloantigen-activated T cells secrete the enzyme specifically when mixed with appropriate stimulator cells. Specific enzyme release is dependent on external calcium and removal of calcium blocks further secretion within a few minutes. Both Lyt-2+ and L3T4+ cells specifically secrete the enzyme with similar rates, and anti-L3T4 and anti-Lyt-2 antibodies block secretion by the responder cells expressing these markers. Anti-LFA-1 antibodies, on the other hand, block secretion by either subset.
mesh_terms: D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis; D002118:Calcium / Q000502:physiology; D003594:Cytoplasmic Granules / Q000201:enzymology; D003602:Cytotoxicity, Immunologic; D010450:Endopeptidases / Q000378:metabolism*; D053804:Granzymes; D007111:Immunity, Cellular; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D012697:Serine Endopeptidases; D013601:T-Lymphocytes / Q000145:classification / Q000502:physiology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly; D000954:Antigens, Surface; D010450:Endopeptidases; D053804:Granzymes; D012697:Serine Endopeptidases; D002118:Calcium