title: CD4 and CD8 homologues in Japanese flounder, Paralichthys olivaceus: Differences in the expressions and localizations of CD4-1, CD4-2, CD8α and CD8β.
abstract: CD4 and CD8 molecules are co-receptors of T cell receptors which interact specifically with MHC class II and I, respectively, during antigen presentation. Here we investigated CD4 and CD8 expression patterns in a fish, Japanese flounder, Paralichthys olivaceus in response to infection and tuberculin injection. The CD4-1 mRNA level was gradually and weakly increased in trunk kidney after infection with Streptococcus iniae, Edwardsiella tarda and viral hemorrhagic septicemia virus (VHSV), while the CD4-2 mRNA level was dramatically increased after E. tarda and VHSV infection, but not increased after S. iniae infection. CD4-2 mRNA but not CD4-1mRNA increased in the kidney during tuberculin response which is mediated by memory Th1 cells. The patterns for the change of mRNA level in CD8α and CD8β were similar to those of the CD4-2 during the infections and tuberculin response. Fluorescent in situ hybridization detected CD4-1 mRNAs on melano-macrophage centers and CD4-2 mRNAs at some cell clusters located near the melano-macrophage centers. CD8α and CD8β mRNAs were detected at the same cell clusters in the spleen and head kidney. These results suggest that CD4-1 and CD4-2 are expressed in different cells and that CD4-2-positive cells, rather than CD4-1-positive cells, have a main role in Th1-related immune responses collaborating with CD8α- and CD8β-positive cells in Japanese flounder.
authors.affiliation: Laboratory of Genome Science, Graduate School of Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato-ku, Tokyo, Japan.
authors.forename: Goshi
authors.initials: G
authors.lastname: Kato
authors.forename: Kana
authors.initials: K
authors.lastname: Goto
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Akune
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Aoka
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Kondo
authors.forename: Ikuo
authors.initials: I
authors.lastname: Hirono
mesh_terms: D000818:Animals; D015704:CD4 Antigens / Q000235:genetics / Q000378:metabolism; D016827:CD8 Antigens / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D003001:Cloning, Molecular; D020609:Edwardsiella tarda / Q000276:immunology*; D004756:Enterobacteriaceae Infections / Q000276:immunology / Q000662:veterinary*; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism; D005432:Flounder / Q000276:immunology* / Q000382:microbiology; D005786:Gene Expression Regulation / Q000276:immunology; D060226:Head Kidney / Q000276:immunology; D029141:Novirhabdovirus / Q000276:immunology*; D018353:Rhabdoviridae Infections / Q000276:immunology / Q000662:veterinary*; D017386:Sequence Homology, Amino Acid; D013290:Streptococcal Infections / Q000276:immunology / Q000662:veterinary*; D013291:Streptococcus / Q000276:immunology*; D014373:Tuberculin / Q000008:administration & dosage
chemical_list: D015704:CD4 Antigens; D016827:CD8 Antigens; C431698:CD8alpha antigen; C477867:CD8beta antigen; D029941:Fish Proteins; D014373:Tuberculin