IFNB1 and infection: The results in Figure 7 show a greater than 1-log fold reduction in viral titers at 24 (Figure 7A) and 48 (Figure 7B) h post-infection, when cells are pre-treated with different doses of IFN-β, for both rIAVs, in comparison to untreated cells that are more susceptible to viral replication following infection with the rIAV expressing NS1-wt.