title: Conservation of characteristics and functions of CD4 positive lymphocytes in a teleost fish.
abstract: The presence of helper and cytotoxic T cells in fish has been suggested, although T cell subsets have yet to be identified at the cellular level. In order to investigate the functions of CD4 and CD8α positive T cells we attempted to produce and characterize monoclonal antibodies (mAbs) against teleost CD4 and CD8α. Here we report the successful production of mAbs against CD4 and CD8α in clonal ginbuna crucian carp Carassius auratus langsdorfii and the function of CD4 positive T cells. In this study we demonstrate the presence of teleost CD4- and CD8α-positive T cell subsets with morphology, tissue distribution and gene expression similar to those of mammalian CD4- and CD8-positive T lymphocytes. Using mAbs we found that CD4/CD8 double positive T cells are only present in the thymus, suggesting that it is the site of T cell development. We further demonstrated in vitro proliferation of CD4 positive T cells by allogeneic combination of mixed leukocyte culture and antigen-specific proliferation of CD4 positive T cells after in vitro sensitization with OVA. In our previous study we showed that CD8α-positive lymphocytes are the primary cell type showing specific cytotoxicity against allogeneic targets. Collectively, these findings suggest that CD4 and CD8α positive T cells in ginbuna are equivalent to helper and cytotoxic T lymphocytes (CTL) in mammals, respectively. This is the first report to show the characteristics and functions of CD4 positive T cells in fish and these findings shed light into the evolutionary origins and primordial functions of helper T cells.
authors.affiliation: Laboratory of Fish Pathology, Department of Veterinary Medicine, Nihon University,1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Toda
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Saito
authors.forename: Takuhito
authors.initials: T
authors.lastname: Koike
authors.forename: Fumio
authors.initials: F
authors.lastname: Takizawa
authors.forename: Kyosuke
authors.initials: K
authors.lastname: Araki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yabu
authors.forename: Tomonori
authors.initials: T
authors.lastname: Somamoto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Suetake
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Ototake
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Moritomo
authors.forename: Teruyuki
authors.initials: T
authors.lastname: Nakanishi
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D015704:CD4 Antigens / Q000096:biosynthesis / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D016827:CD8 Antigens / Q000096:biosynthesis / Q000276:immunology; D002347:Carps / Q000235:genetics* / Q000276:immunology; D049109:Cell Proliferation; D048430:Cell Shape; D002478:Cells, Cultured; D018920:Coculture Techniques; D005260:Female; D005434:Flow Cytometry; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000096:biosynthesis / Q000276:immunology; D007106:Immune Sera; D007962:Leukocytes / Q000378:metabolism; D009928:Organ Specificity; D010446:Peptide Fragments / Q000096:biosynthesis / Q000276:immunology; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D016827:CD8 Antigens; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007106:Immune Sera; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; C475510:tyrosyl-prolyl-tyrosyl-aspartyl-valyl-prolyl-aspartyl-tyrosyl-alanine