title: Transcriptional characterization of the T cell population within the salmonid interbranchial lymphoid tissue.
abstract: Previously, our group has shown that the interbranchial lymphoid tissue (ILT) is a distinct structure largely consisting of T cells embedded in a meshwork of epithelial cells, with no direct resemblance to previously described lymphoid tissues. In this study, we aim to focus on the T cell population and the possibility of the ILT being a thymus analog. By characterizing structural responsiveness to Ag challenge, the presence of recombination activating genes, and different T cell-related transcripts, we attempt to further approach the immunological function of the ILT in salmonid gills. In addition to eight healthy individuals, a group of eight infectious salmon anemia virus-challenged fish were included to observe T cell responses related to infection. The results showed reduced size of ILT in the infected group, no expression of RAG-1 and -2, and a high degree of T cell diversity within the ILT. Taking into account that the ILT can be regarded as a strategically located T cell reservoir and possibly an evolutionary forerunner of mammalian MALTs right at the border to the external environment, the alteration in transcription observed may likely represent a shift in the T cell population to optimize local gill defense mechanisms.
authors.affiliation: Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, 0454 Oslo, Norway;
authors.forename: Ida Bergva
authors.initials: IB
authors.lastname: Aas
authors.affiliation: Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, 0454 Oslo, Norway;
authors.forename: Lars
authors.initials: L
authors.lastname: Austbø
authors.affiliation: Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, 0454 Oslo, Norway;
authors.forename: Melanie
authors.initials: M
authors.lastname: König
authors.affiliation: Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, 0454 Oslo, Norway;
authors.forename: Mohasina
authors.initials: M
authors.lastname: Syed
authors.affiliation: Norwegian Veterinary Institute, 0454 Oslo, Norway; and.
authors.forename: Knut
authors.initials: K
authors.lastname: Falk
authors.affiliation: Department of Biology, High Technology Centre, University of Bergen, 5006 Bergen, Norway.
authors.forename: Ivar
authors.initials: I
authors.lastname: Hordvik
authors.affiliation: Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, 0454 Oslo, Norway;
authors.forename: Erling O
authors.initials: EO
authors.lastname: Koppang
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000276:immunology; D005786:Gene Expression Regulation / Q000276:immunology*; D005880:Gills / Q000166:cytology / Q000276:immunology*; D018398:Homeodomain Proteins / Q000276:immunology; D008221:Lymphoid Tissue / Q000166:cytology / Q000276:immunology*; D020317:Salmo salar / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D014158:Transcription, Genetic / Q000276:immunology*
chemical_list: D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C064655:V(D)J recombination activating protein 2; C064658:RAG-1 protein