title: Expression of CTLA-4 (CD152) on human medullary CD4+ thymocytes.
abstract: CTLA-4 (CD152) is a T cell surface receptor with sequence homology to the co-stimulatory molecule CD28. The molecule, which is essential for the inhibitory regulation of the immune response, becomes transiently expressed on mature T cells after stimulation in vitro. In situ, CTLA-4+ T cells are enriched in the light zones of the germinal centers in human peripheral lymphoid organs. In this study we have studied expression of CTLA-4 in human thymus in situ. CTLA-4 was expressed on about one third of CD4+/CD8-/CD1- medullary thymocytes. CTLA-4 was acquired by a subset of immature (CD1+) thymocytes and lost from the mature (CD1-) subpopulation within 48 h of cell culture, suggesting that the expression on medullary thymocytes is transient. The demonstration of CTLA-4 on a substantial subpopulation of mature CD4+ thymocytes adds a new dimension to the understanding of this important molecule. When contemplating application of anti-CTLA-4 for therapy its potential influence on T cell maturation has to be taken into account.
authors.affiliation: Abteilung für Klinische Mikrobiologie und Immunologie, Bernhard-Nocht-Institut für Tropenmedizin, Hamburg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Castan
authors.forename: U
authors.initials: U
authors.lastname: Klauenberg
authors.forename: P
authors.initials: P
authors.lastname: Kalmár
authors.forename: B
authors.initials: B
authors.lastname: Fleischer
authors.forename: B M
authors.initials: BM
authors.lastname: Bröker
mesh_terms: D000069594:Abatacept; D000818:Animals; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000378:metabolism*; D015704:CD4 Antigens / Q000276:immunology*; D060908:CTLA-4 Antigen; D002478:Cells, Cultured; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D018796:Immunoconjugates; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D013950:Thymus Gland / Q000276:immunology; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D015704:CD4 Antigens; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; C556707:Ctla4 protein, mouse; D018796:Immunoconjugates; D000069594:Abatacept