ISG15 and infection: In addition to IFN-β, we observed that the expression of IFN-α, IL-28, MxA and OASL was also increased in NS1-S212P transfected cells comparing with that in NS1-WT transfected 293T cells after infection with WSN virus, while the expression of IL-29 and ISG15 was not influenced in these cells (Figures 2B–F, Additional file 2A).