Effect of double-stranded RNA and interferon on the antiviral activity of Atlantic salmon cells against infectious salmon anemia virus and infectious pancreatic necrosis virus.
Type I interferons (IFN) establish an antiviral state in vertebrate cells by inducing expression of Mx and other antiviral proteins. We have studied the effect of Atlantic salmon interferon-like activity (AS-IFN) and poly I:C on the Mx protein expression and antiviral activity against infectious salmon anaemia virus (ISAV) and infectious pancreatic necrosis virus (IPNV) in the Atlantic salmon cell lines SHK-1 and TO. The double-stranded RNA poly I:C is an inducer of type I IFN in vertebrates. A cell cytotoxicity assay and measurements of virus yield were used to measure protection of cells against virus infection. Maximal induction of Mx protein in TO and SHK-1 cells occurred 48 h after poly I:C stimulation and 24 h after AS-IFN stimulation. TO cells pretreated with AS-IFN or poly I:C were protected from infection with IPNV 24 to 96 h after stimulation. Poly I:C or AS-IFN induced a minor protection against ISAV infection in SHK-1 cells, but no protection was induced against ISAV in TO cells. Western blot analysis showed that ISAV induced expression of Mx protein in TO and SHK-1 cells whereas IPNV did not induce Mx protein expression. These results suggest that ISAV and IPNV have very different sensitivities to IFN-induced antiviral activity and have developed different strategies to avoid the IFN-system of Atlantic salmon. Moreover, Atlantic salmon Mx protein appears not to inhibit replication of ISAV.
D000818:Animals; D000998:Antiviral Agents / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D018175:Birnaviridae Infections / Q000235:genetics / Q000276:immunology / Q000662:veterinary; D015153:Blotting, Western / Q000662:veterinary; D002460:Cell Line; D005393:Fish Diseases / Q000235:genetics / Q000276:immunology; D019204:GTP-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D018061:Infectious pancreatic necrosis virus / Q000276:immunology; D007370:Interferon Type I / Q000494:pharmacology*; D064547:Myxovirus Resistance Proteins; D009975:Orthomyxoviridae / Q000276:immunology; D009976:Orthomyxoviridae Infections / Q000235:genetics / Q000276:immunology / Q000662:veterinary; D011070:Poly I-C / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D012330:RNA, Double-Stranded / Q000494:pharmacology*; D020317:Salmo salar / Q000276:immunology; D014779:Virus Replication
D000998:Antiviral Agents; D007370:Interferon Type I; D064547:Myxovirus Resistance Proteins; D012330:RNA, Double-Stranded; D019204:GTP-Binding Proteins; D011070:Poly I-C