title: The role of Ca2+ and Mg2+ in the cytotoxic T lymphocyte reaction and in the secretion of N alpha-benzyloxycarbonyl-L-lysine thiobenzyl ester-serine esterase by human T cell clones.
abstract: Human T cell clones contain enzymes that can cleave the substrate N-alpha-benzyloxycarbonyl-L-lysine thiobenzyl ester (BLT). All CTL clones tested in this study secreted BLT-serine esterase activity, whereas only one of three tested non-cytolytic T cell clones secreted this enzymatic activity upon Ag-specific activation. BLT-serine esterase secretion could also be induced by the Fc gamma+ target cell Daudi in the presence of mAb specific for the TCR/CD3 complex, CD2, or the T cell activation Ag Tp 103. In addition, anti-CD3 and a mitogenic combination of anti-CD2 mAb, induced secretion of BLT-serine esterase in the absence of target cells, whereas anti-Tp 103 failed to do so. The secreted BLT-serine esterase activity induced by the various ligands was inhibited by the serine esterase inhibitors PMSF and m-ABA, but not by N-alpha-p-tosyl-L-lysine chloromethyl ketone. Significant BLT-serine esterase activity was induced by target cells or soluble anti-CD3 in the absence of extracellular Ca2+ ions, provided that extracellular Mg2+ ions were present. The cytotoxic activities by the human CTL clones were completely blocked under these conditions. All ligands that induced BLT-serine esterase secretion in the absence of extracellular Ca2+, induced a transient rise of intracellular Ca2+. Soluble anti-CD3 mAb did not induce a transient rise in intracellular Ca2+ or secretion of BLT serine esterase in CTL preincubated for 2 h with 5 mM EGTA. These findings indicate that mobilization of intracellular Ca2+ in human CTL clones is required for induction of secretion of BLT-serine esterase.
authors.affiliation: UNICET, Laboratories for Immunological Research, Dardilly, France.
authors.forename: D
authors.initials: D
authors.lastname: Blanchard
authors.forename: J P
authors.initials: JP
authors.lastname: Aubry
authors.forename: J E
authors.initials: JE
authors.lastname: de Vries
authors.forename: H
authors.initials: H
authors.lastname: Spits
mesh_terms: D000911:Antibodies, Monoclonal / Q000502:physiology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D018801:CD2 Antigens; D017252:CD3 Complex; D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D002999:Clone Cells / Q000201:enzymology / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D005110:Extracellular Space / Q000502:physiology; D053804:Granzymes; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism; D008213:Lymphocyte Activation; D008274:Magnesium / Q000502:physiology*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D011971:Receptors, Immunologic / Q000276:immunology; D012697:Serine Endopeptidases / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors; D013602:T-Lymphocytes, Cytotoxic / Q000201:enzymology* / Q000276:immunology; D014361:Trypsin Inhibitors / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D018801:CD2 Antigens; D017252:CD3 Complex; D011948:Receptors, Antigen, T-Cell; D011971:Receptors, Immunologic; D015842:Serine Proteinase Inhibitors; D014361:Trypsin Inhibitors; D053804:Granzymes; D012697:Serine Endopeptidases; C509212:GZMA protein, human; D008274:Magnesium; D002118:Calcium