title: Effects of irradiation, glucocorticoid and FK506 on cell-surface antigen expression by rat thymocytes: a three-colour flow cytofluorometric analysis.
abstract: The expression of T-cell antigen receptor (TCR) alpha beta was investigated in rat CD4- CD8- thymocytes during thymic reconstitution after the exposure of animals to irradiation or glucocorticoid. The effect of the immunosuppressant FK506 on the expression of TCR alpha beta in rat CD4- CD8- thymocytes was also examined. The percentage of CD4- CD8- thymocytes constituted 2.6% of total thymocytes and that of CD4- CD8- TCR alpha beta high cells constituted 12.6% of CD4- CD8- thymocytes in normal adult Lewis rats. The percentage of CD4- CD8- TCR alpha beta high cells increased during thymic reconstitution after irradiation, and maximally constituted 28.6% of CD4- CD8- thymocytes on day 7. Similar results were obtained during thymic reconstitution after glucocorticoid treatment. In contrast, continuous treatment with FK506 for 7 days markedly decreased not only the percentages of CD4+ CD8- TCR alpha beta high and CD4- CD8+ TCR alpha beta high thymocytes, but also that of CD4- CD8- TCR alpha beta high thymocytes. These results indicate that rat CD4- CD8- thymocytes contain a subpopulation of mature (TCR alpha beta high) cells. The possible implications of the existence of this subpopulation with regard to thymocyte differentiation and maturation are discussed.
authors.affiliation: Department of Urology, Yamaguchi University School of Medicine, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Tsuchida
authors.forename: M
authors.initials: M
authors.lastname: Konishi
authors.forename: K
authors.initials: K
authors.lastname: Takai
authors.forename: K
authors.initials: K
authors.lastname: Naito
authors.forename: Y
authors.initials: Y
authors.lastname: Fujikura
authors.forename: T
authors.initials: T
authors.lastname: Fukumoto
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003907:Dexamethasone / Q000494:pharmacology; D005434:Flow Cytometry; D008297:Male; D051381:Rats; D011917:Rats, Inbred Lew; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*; D016559:Tacrolimus / Q000494:pharmacology*; D013950:Thymus Gland / Q000166:cytology / Q000187:drug effects / Q000276:immunology* / Q000528:radiation effects
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta; D003907:Dexamethasone; D016559:Tacrolimus