Monoclonal antibodies directed against the E2 protein (MIC2 gene product) induce exposure of phosphatidylserine at the thymocyte cell surface.
Monoclonal antibodies (mAbs) directed against E2, a 32-kDa transmembrane protein encoded by the MIC2 gene located in the pseudoautosomal region, induce a transbilayer movement of phosphatidylserine and, to a lesser extent, phosphatidylethanolamine in human thymocytes and a Jurkat T lymphocytes. The translocation of phosphatidylserine has been evidenced by using either derivatization of anionic phospholipids with trinitrobenzenesulfonate (TNBS) or cytofluorimetry after labeling of cells with antiphosphatidylserine antibodies. The perturbation of membrane phospholipids induced by anti-E2 mAbs was further evidenced by labeling the cells with merocyanine 540. The specificity of anti-E2-induced perturbations of membrane asymmetry was tested by using a number of mAbs able to activate T cells, including CD3 and CD2. The results strongly suggest that anti-E2-induced changes in PtdSer are related to cell aggregation since the same mAbs specifically induce the aggregation of both thymocytes and Jurkat cells and since the E2 molecule has been previously implicated in the adhesive properties of human T cells with erythrocytes.
INSERM U343, Faculté de Médecine, Nice, France.
C
C
Aussel
G
G
Bernard
J P
JP
Breittmayer
C
C
Pelassy
D
D
Zoccola
A
A
Bernard
D000071443:12E7 Antigen; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D015703:Antigens, CD; D015815:Cell Adhesion Molecules / Q000276:immunology*; D002478:Cells, Cultured; D019856:Ethanolamine; D004983:Ethanolamines / Q000378:metabolism; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D006801:Humans; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000276:immunology*; D010714:Phosphatidylethanolamines / Q000378:metabolism*; D010718:Phosphatidylserines / Q000378:metabolism*; D011744:Pyrimidinones; D012694:Serine / Q000378:metabolism; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D013950:Thymus Gland / Q000276:immunology; D014316:Tritium; D014407:Tumor Cells, Cultured
D000071443:12E7 Antigen; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; D004983:Ethanolamines; D005456:Fluorescent Dyes; D008562:Membrane Glycoproteins; D010714:Phosphatidylethanolamines; D010718:Phosphatidylserines; D011744:Pyrimidinones; D014316:Tritium; D012694:Serine; C003954:merocyanine dye; D019856:Ethanolamine