title: Rag expression identifies B and T cell lymphopoietic tissues during the development of common carp (Cyprinus carpio).
abstract: The generation of lymphoid cells during carp development was studied by analyzing expression of the recombination activating genes (rag) using in situ hybridization and real time quantitative PCR. These data were combined with immunohistochemistry using the mAb's WCL9 (cortical thymocytes) and WCI12 (B cells). Carp rag-1 and rag-2 showed 90 and 89% amino acid identity, respectively, to the corresponding zebrafish sequences. Rag-1 was first expressed in the thymus at 4 days post-fertilization (dpf), while both rag-1+/WCL9+ and rag-1-/WCL9- areas were distinguished from 1 week post-fertilization (wpf), suggesting early cortex/medulla differentiation. From 6 dpf, rag-1+ cells were also present cranio-lateral of the head kidney. From 1 wpf, rag-1/rag-2 was expressed in kidney (together with immunoglobulin heavy chain expression) but not in spleen, while WCI12+ cells appeared 1 week later in both organs, suggesting B cell recombination in kidney but not in spleen. Rag-1 expression exceeded rag-2 levels in thymus and in head- and trunk-kidney of juveniles, but this ratio was reversed in head- and trunk-kidney from approximately 16 wpf onwards. Rag-1/rag-2 expression was detected in thymi of animals over 1-year-old, but in kidney only at low levels, indicating life-long new formation of putative T cells but severely reduced formation of B cells in older fish.
authors.affiliation: Cell Biology and Immunology Group, Wageningen Institute of Animal Sciences, Wageningen University, Marijkeweg 40, 6709 PG, Wageningen, The Netherlands.
authors.forename: Heidi B T
authors.initials: HB
authors.lastname: Huttenhuis
authors.forename: Mark O
authors.initials: MO
authors.lastname: Huising
authors.forename: Talitha
authors.initials: T
authors.lastname: van der Meulen
authors.forename: Carolien N
authors.initials: CN
authors.lastname: van Oosterhoud
authors.forename: Nuria Alvarez
authors.initials: NA
authors.lastname: Sánchez
authors.forename: Anja J
authors.initials: AJ
authors.lastname: Taverne-Thiele
authors.forename: Henri W J
authors.initials: HW
authors.lastname: Stroband
authors.forename: Jan H W M
authors.initials: JH
authors.lastname: Rombout
mesh_terms: D000367:Age Factors; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002347:Carps / Q000254:growth & development / Q000276:immunology*; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000378:metabolism; D007814:Larva / Q000276:immunology; D038041:Lymphopoiesis; D008969:Molecular Sequence Data; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology
chemical_list: D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D007143:Immunoglobulin Heavy Chains; C064655:V(D)J recombination activating protein 2; C064658:RAG-1 protein