title: Effects of cyclosporin A on T-cell development in organ-cultured foetal thymus.
abstract: The effects of cyclosporin A (CsA) on T-cell development were assessed in an organ culture of murine foetal thymus. Applying three-colour flow cytometric analysis, we showed that the agent inhibits the development of mature CD3/T-cell receptor alpha beta (TcR alpha beta)+ cells both in CD4+8- and CD4-8+ populations. CD4-8- cells appeared to be accumulated by CsA. We examined the heterogeneity of CD4-8- cells generated in the organ culture, and defined five subpopulations by the expression of the cell-surface molecules CD3/TcR, J11d and CD25. It has been demonstrated that only the CD3/TcR alpha beta+ J11d- CD25- subpopulation is susceptible to the suppressive effects of CsA among CD4-8- cells, whereas all the other four subpopulations, including CD3/TcR gamma delta+ cells, are resistant. Thus, all of the TcR alpha beta-bearing cells, including CD4-8- cells but none of the TcR alpha beta- cells, are CsA sensitive. Because it is known that CsA inhibits the TcR-mediated signalling events in mature T cells and that signallings mediated via the interaction of TcR with major histocompatibility complex (MHC) molecules on thymic stroma cells are crucial for thymic selection of T cells, these results indicate that TcR alpha beta-bearing CD4-8- cells but not TcR gamma delta-bearing CD4-8- cells undergo thymic positive selection.
authors.affiliation: Second Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: T
authors.initials: T
authors.lastname: Horiuchi
authors.forename: T
authors.initials: T
authors.lastname: Sugimoto
authors.forename: H
authors.initials: H
authors.lastname: Matsuda
authors.forename: H
authors.initials: H
authors.lastname: Yagita
authors.forename: K
authors.initials: K
authors.lastname: Okumura
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D002454:Cell Differentiation / Q000187:drug effects; D003524:Cyclosporins / Q000494:pharmacology*; D005333:Fetus / Q000276:immunology; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D009924:Organ Culture Techniques; D011948:Receptors, Antigen, T-Cell / Q000032:analysis; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects*; D013950:Thymus Gland / Q000196:embryology* / Q000276:immunology
chemical_list: D015703:Antigens, CD; D003524:Cyclosporins; D011948:Receptors, Antigen, T-Cell