title: Majority of TcRbeta+ T-lymphocytes located in thymus and midgut of the bony fish, Dicentrarchus labrax (L.).
abstract: Real-time polymerase chain reaction (PCR) and in situ hybridization analyses were performed to investigate the occurrence and distribution of T-lymphocytes expressing TcRbeta in intestine and lymphoid tissues of the bony fish, Dicentrarchus labrax (sea bass). Immunohistochemistry with the monoclonal antibody DLT15 (pan-T-cell marker) was carried out to compare the cytology, distribution and number of T-cells and TcRbeta+ cells in the various sampled lymphoid organs. The highest TcRbeta expression was revealed by real-time PCR in the thymus, with high levels also being found in the gut. In the thymus, DLT15+ and TcRbeta+ cell populations were concentrated in the cortex and TcRbeta+ cells were notably reactive at the cortical-medullary border, suggesting a specialized role of this region in thymocyte selection. The density of DLT15+ T-cells increased from the anterior to posterior intestine, whereas TcRbeta+ lymphocytes were more numerous in the middle intestine compared with other segments. The existence, in fish thymus, of a medulla and a cortex comparable with those of mammals is revealed by this study. The concentration of TcRbeta+ cells in the sea bass midgut also strongly suggests a special role of this intestinal segment in antigen-specific cellular immunity. The large population of TcRbeta(-)/DLT15+ T-cells in the posterior gut can probably be ascribed to the TcRgammadelta phenotype fraction.
authors.affiliation: Department of Environmental Sciences, Tuscia University, Viterbo, Italy. nromano@unitus.it
authors.forename: Nicla
authors.initials: N
authors.lastname: Romano
authors.forename: Francesca
authors.initials: F
authors.lastname: Rossi
authors.forename: Luigi
authors.initials: L
authors.lastname: Abelli
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Caccia
authors.forename: Rita
authors.initials: R
authors.lastname: Piergentili
authors.forename: Lucia
authors.initials: L
authors.lastname: Mastrolia
authors.forename: Elisa
authors.initials: E
authors.lastname: Randelli
authors.forename: Francesco
authors.initials: F
authors.lastname: Buonocore
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000166:cytology; D001492:Bass / Q000276:immunology*; D007422:Intestines / Q000166:cytology*; D007668:Kidney / Q000166:cytology; D008221:Lymphoid Tissue / Q000166:cytology; D016133:Polymerase Chain Reaction; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis*; D013154:Spleen / Q000166:cytology; D016176:T-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D016693:Receptors, Antigen, T-Cell, alpha-beta