title: Enhancement of CD3-mediated thymocyte apoptosis by the cross-linkage of heat-stable antigen.
abstract: Heat-stable antigen (HSA) is a murine differentiating antigen that is expressed on both CD4-CD8- double-negative and CD4+CD8+ double-positive thymocytes but not CD4+ or CD8+ single-positive thymocytes. Effects of anti-HSA monoclonal antibody, R13, on thymocyte apoptosis induced by various stimulations were investigated by a single-cell suspension culture system. Immobilized R13 enhanced the CD3-mediated DNA fragmentation and killing of thymocytes but not the dexamethasone-induced or phorbol myristate acetate-induced killing of thymocytes. Immobilized R13 by itself could not induce thymocyte apoptosis. Soluble R13 enhanced CD3-mediated apoptosis when HSA and T-cell receptor (TCR)/CD3 were co-cross-linked by a cross-reactive secondary antibody. Even without the cross-reactive secondary antibody, soluble R13 enhanced CD3-mediated apoptosis, although a greater than 100-fold increase in the amount of R13 was needed to give a similar enhancement compared with immobilized R13. Neither R13 by itself nor R13 plus secondary antibody induced cytosolic calcium influx, whereas R13 enhanced CD3-mediated cytosolic calcium increase. These results suggest a functional role of HSA in promoting the activation-induced apoptosis of thymocytes and the involvement of HSA in negative selection.
authors.affiliation: Department of Clinical Laboratory Medicine, Ehime University School of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hitsumoto
authors.forename: D S
authors.initials: DS
authors.lastname: Song
authors.forename: M
authors.initials: M
authors.lastname: Okada
authors.forename: F
authors.initials: F
authors.lastname: Hamada
authors.forename: S
authors.initials: S
authors.lastname: Saheki
authors.forename: N
authors.initials: N
authors.lastname: Takeuchi
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000276:immunology*; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology*; D051927:CD24 Antigen; D017252:CD3 Complex / Q000276:immunology; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D005938:Glucocorticoids / Q000494:pharmacology; D008562:Membrane Glycoproteins; D051379:Mice; D008810:Mice, Inbred C57BL; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D051927:CD24 Antigen; D017252:CD3 Complex; C497890:Cd24a protein, mouse; D005938:Glucocorticoids; D008562:Membrane Glycoproteins; D017260:Receptor-CD3 Complex, Antigen, T-Cell; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium