Rag expression identifies B and T cell lymphopoietic tissues during the development of common carp ( Cyprinus carpio)

• Published in: Developmental and comparative immunology 2005, Vol.29 (12), p.1033-1047
• Main Authors: Huttenhuis, Heidi B.T., Huising, Mark O., van der Meulen, Talitha, van Oosterhoud, Carolien N., Sánchez, Nuria Alvarez, Taverne-Thiele, Anja J., Stroband, Henri W.J., Rombout, Jan H.W.M.
• Format: Article
• Language: English
• Subjects: activating gene-1 rag1; Age Factors; Aging; Animals; B cells; B-Lymphocytes - cytology; B-Lymphocytes - immunology; Carp; Carps - growth & development; Carps - immunology; class-i; Cortex; developing zebrafish; DNA-Binding Proteins - biosynthesis; DNA-Binding Proteins - genetics; Gene Expression Regulation, Developmental; Homeodomain Proteins - genetics; Homeodomain Proteins - metabolism; Immunoglobulin Heavy Chains - genetics; Immunoglobulin Heavy Chains - metabolism; involution; Larva - immunology; Lymphopoiesis; Molecular Sequence Data; Ontogeny; Rag; system; T cells; T-Lymphocytes - cytology; T-Lymphocytes - immunology; thymocytes; Thymus; Thymus Gland - cytology; Thymus Gland - immunology; trout oncorhynchus-mykiss; v(d)j recombination
• ISSN: 0145-305X; 1879-0089
• DOI: 10.1016/j.dci.2005.03.005

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.