IFNB1 and infection: Low multiplicity of infection (MOI) infection of Hep3BP or B16 cells with VSV-IFNβ-CSDE1WT significantly reduced both escape (Fig. 4C) and the escape-enabling CSDE1C-T mutation (~10–50% in Fig. 4D, compared to >90% in Supplementary Fig. 1I) compared to VSV-IFNβ.