title: Induction of Mx protein by interferon and double-stranded RNA in salmonid cells.
abstract: Mx protein is one of several antiviral proteins that are induced by the type I interferons (IFN), IFNalpha and beta, in mammals. In this work induction of a 76 kDa Mx protein by double-stranded RNA (dsRNA) or type I IFN-like activity in Atlantic salmon macrophages, Atlantic salmon fibroblast cells (AS cells) and in Chinook salmon embryo cells (CHSE-214) is reported. Type I IFN-like activity was produced by the stimulation of Atlantic salmon macrophages with the synthetic dsRNA polyinosinic polycytidylic acid (poly I:C). A correlation appeared to exist between Mx protein expression and protection against infectious pancreatic necrosis virus (IPNV) induced by IFN in CHSE-214 cells. Several observations in the present work suggest that, as in mammals, the induction of Mx protein by dsRNA in fish cells primarily occurs via induction of type I IFN. First, type I IFN-like activity but not poly I:C, induced Mx protein expression in CHSE-214 cells. These cells apparently lack the ability to produce IFN in response to poly I:C. Second, the putative IFN induced maximal Mx protein expression 48 h earlier than poly I:C in AS cells. Third, the peak expression of Mx protein in macrophages induced by poly I:C occurred after 48 h whereas peak in IFN-like activity was observed by 24 h after addition of poly I:C. The present work supports the notion of using Mx protein as a molecular marker for the production of putative type I IFN in fish.
authors.affiliation: The Norwegian College of Fishery Science, University of Tromsø.
authors.forename: R
authors.initials: R
authors.lastname: Nygaard
authors.forename: S
authors.initials: S
authors.lastname: Husgard
authors.forename: A I
authors.initials: AI
authors.lastname: Sommer
authors.forename: J A
authors.initials: JA
authors.lastname: Leong
authors.forename: B
authors.initials: B
authors.lastname: Robertsen
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000096:biosynthesis*; D015153:Blotting, Western / Q000662:veterinary; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D019204:GTP-Binding Proteins; D007370:Interferon Type I / Q000494:pharmacology*; D016350:Leucine Zippers; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D064547:Myxovirus Resistance Proteins; D011070:Poly I-C / Q000494:pharmacology; D014176:Protein Biosynthesis; D012330:RNA, Double-Stranded / Q000494:pharmacology*; D020317:Salmo salar
chemical_list: D000998:Antiviral Agents; D007370:Interferon Type I; D064547:Myxovirus Resistance Proteins; D012330:RNA, Double-Stranded; D019204:GTP-Binding Proteins; D011070:Poly I-C