Alpha Interferon and Not Gamma Interferon Inhibits Salmonid Alphavirus Subtype 3 Replication In Vitro

Antiviral Activity of Salmonid Gamma Interferon against Infectious Pancreatic Necrosis Virus and Salmonid Alphavirus and Its Dependency on Type I Interferon

“…However, the reason for the difference in results is probably that recombinant salmon IFN-␥ produced in E. coli from inclusion bodies is inactive. Salmon IFN-␥ prepared this way induced only 30-and 12-fold increases in IP-10 at 1.65 g/ml and 330 ng/ml, respectively (57). We obtained similar results with salmon IFN-␥ produced from inclusion bodies in E. coli (data not shown).…”

“…Previous research showed that IFN-␥ also upregulated the transcription of TLR8 and TLR9 homologs in salmon, which should further contribute to the priming of cells for an enhanced antiviral response (47,48). A recent report claimed that salmon IFN-␥ has no antiviral activity against SAV3, which is in disagreement with the present results (57). However, the reason for the difference in results is probably that recombinant salmon IFN-␥ produced in E. coli from inclusion bodies is inactive.…”

“…This is in contrast to a recent report, which stated that salmon IFN-␥ had no ability to inhibit replication of SAV3 (57). Gene induction studies demonstrated that IFN-␥ is a less potent inducer of the typical antiviral genes Mx, ISG15, viperin, and PKR compared to IFNa1 but is a more effective inducer of GBP and several IRFs than IFNa1.…”

Natural infection of Atlantic salmon (Salmo salar L.) with salmonid alphavirus 3 generates numerous viral deletion mutants

“…Despite the confirmed presence of viral RNA by PCR in infected tissues prior to isolation in cell culture, we observed that a large number of these viral genomes were incomplete, being unable to sustain an infection by themselves. These defective viral variants will also be potent activators of the interferoninduced responses, and it is well known that alpha interferon as part of the immune response is a strong inhibitor of SAV3 replication in vitro (Xu et al, 2010). DIPs cannot sustain infection themselves but are efficiently replicated and encapsidated using proteins produced by wild-type viral genomes (García-Arriaza et al, 2004), which was also the case for SAV.…”

A Single Amino Acid Mutation (I1012F) of the RNA Polymerase of Marine Viral Hemorrhagic Septicemia Virus Changes In Vitro Virulence to Rainbow Trout Gill Epithelial Cells

“…VHSV was identified by IFAT with monoclonal antibody (MAb) IP5B11 (anti-N protein) (15) as the primary antibody. Anti-rainbow trout Mx antibody was used to detect Mx protein in infected cells (22). Stained cells were washed and examined with an inverted Olympus IX81 fluorescence microscope.…”