IFNA1 and viral infectious disease: Since the primary role of IAV NS1 protein is to inhibit IFN and host antiviral responses during viral infection [11,32,37,38], we explored the effect of substituting NS1 with mCherry, on the capacity of the virus to inhibit induction of IFNβ by using a well-characterized cell-based IFNβ bioassay (Figure 4A).