Because a FACS-based assay is used to detect infected cells (not for mature virus), a higher virus titer was obtained than TCID50 at 12 hrs p.i. After treatment with the culture supernatants containing IFNβ for 6, 12 and 24 hrs, respectively, cells were infected with VSV*GFP, and inhibition of the virus infection was enhanced following a prolonged treatment in VISA+/+ cells, but not in VISA−/− cells, suggesting that inhibition of virus replication by IFNβ was a dose-dependent manner. This evidence concerns the gene IFNB1 and viral infectious disease.