title: Compartmentalisation of T cells expressing CD8alpha and TCRbeta in developing thymus of sea bass Dicentrarchus labrax (L.).
abstract: Eggs, larvae, post-larvae and sexually immature juveniles of the teleost Dicentrarchus labrax (L.) were assayed for the expression of genes encoding the T cell receptor beta and CD8alpha. RT-PCR of RNA extracted from larvae revealed TCRbeta transcripts from day 25 post-hatching (ph) and CD8alpha transcripts from 26 days later. At day 51 ph, CD8alpha and TCRbeta mRNAs were localised by in situ hybridisation in thymocytes of the outer and lateral zones of the thymic paired glands. From day 75 ph onwards the signal was mainly detected in the outer region, drawing a cortex-medulla demarcation. In 1-year-old fish, CD8alpha+ and TCRbeta+ thymocytes almost filled the cortex and extended in large cords in the medulla. A CD8alpha(-)TCRbeta+ subcapsular lymphoid zone was evident near the septa coming from the inner connective capsule that delimited the thymus. The localisation of CD8alpha and TCRbeta transcripts demonstrated a compartmentalisation of the juvenile thymus due to distinct localisation of thymocytes at different developmental stages.
authors.affiliation: Dipartimento Scienze Ambientali, Università della Tuscia, 01100 Viterbo, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Picchietti
authors.forename: Laura
authors.initials: L
authors.lastname: Guerra
authors.forename: Luigi
authors.initials: L
authors.lastname: Selleri
authors.forename: Francesco
authors.initials: F
authors.lastname: Buonocore
authors.forename: Luigi
authors.initials: L
authors.lastname: Abelli
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Scapigliati
authors.forename: Massimo
authors.initials: M
authors.lastname: Mazzini
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Fausto
mesh_terms: D000818:Animals; D001492:Bass / Q000235:genetics / Q000254:growth & development / Q000276:immunology*; D016827:CD8 Antigens / Q000235:genetics / Q000378:metabolism*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D015870:Gene Expression; D017403:In Situ Hybridization; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000254:growth & development / Q000276:immunology*
chemical_list: D016827:CD8 Antigens; D016693:Receptors, Antigen, T-Cell, alpha-beta