IFNB1 and infection: At this early stage of viral replication time point, relative to VSV-IFNβ infection of parental cell types, the levels of P–M bicistronic RNA were increased between 20- and 30-fold upon infection of Hep3B, or B16, cells with VSV-IFNβ-IGR P/MC-U, and between 10- and 30-fold in both Hep3B and B16 cells overexpressing CSDE1P5S infected with VSV-IFNβ (Fig. 3C).