title: The rainbow trout classical MHC class I molecule Onmy-UBA*501 is expressed in similar cell types as mammalian classical MHC class I molecules.
abstract: Onmy-UBA is a polymorphic classical major histocompatibility (MHC) class I locus in rainbow trout (Oncorhynchus mykiss). A common allomorph is Onmy-UBA*501, which has been detected in several wildtype strains, in the clonal homozygous rainbow trout C25 and, in the current study, in the rainbow trout gonad cell line RTG-2. The extracellular domain of this allomorph was expressed in E. coli and a murine monoclonal antibody designated H9 was generated against the recombinant protein. In Western blot analysis Mab H9 specifically recognised an n-glycosylated protein of 45 kDa in leucocytes and erythrocytes of C25 fish and in RTG-2 cells. The level of Onmy-UBA*501 expression in erythrocytes was very low. Immunocytochemistry of isolated cells indicated expression in lymphocytes, macrophages, neutrophils, erythrocytes, RTG-2 cells and Onmy-UBA *501 transfected CHO cells, but not in untransfected CHO cells. Immunohistochemistry using frozen sections of C25 fish indicated that Onmy-UBA*501 expression is strong in the lymphoid organs (thymus, head kidney and spleen) and in the epithelia and endothelia of several organs. No significant expression was observed in muscle fibres, hepatocytes or neurons. These observations demonstrate that in jawed fish, the lowest phylogenetic group possessing an MHC system, the classical MHC class I molecules are expressed in similar cell types as in higher vertebrates.
authors.affiliation: Immunology Section, National Research Institute of Aquaculture, Tamaki Mie, 519-0423, Japan.
authors.forename: Johannes M
authors.initials: JM
authors.lastname: Dijkstra
authors.forename: Bernd
authors.initials: B
authors.lastname: Köllner
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Aoyagi
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sawamoto
authors.forename: Akashi
authors.initials: A
authors.lastname: Kuroda
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Ototake
authors.forename: Teruyuki
authors.initials: T
authors.lastname: Nakanishi
authors.forename: Uwe
authors.initials: U
authors.lastname: Fischer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D015153:Blotting, Western / Q000662:veterinary; D016466:CHO Cells; D002460:Cell Line; D006224:Cricetinae; D018076:DNA, Complementary / Q000032:analysis; D004912:Erythrocytes / Q000276:immunology; D019084:Fluorescent Antibody Technique, Indirect / Q000662:veterinary; D015870:Gene Expression; D005805:Genes, MHC Class I; D006031:Glycosylation; D015395:Histocompatibility Antigens Class I / Q000737:chemistry* / Q000235:genetics* / Q000276:immunology; D007150:Immunohistochemistry / Q000662:veterinary; D007962:Leukocytes / Q000276:immunology; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss / Q000235:genetics / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D018076:DNA, Complementary; D015395:Histocompatibility Antigens Class I