FIG. 5.

The ISP does not require the IFN-α/β receptor for induction of IFN-α/β but does require it for the antiviral effects mediated by this cytokine. Primary IFN-α/β IFNAR1^−/− fibroblasts were treated for 24 h with serial dilutions of either IFN-γ, IFN-αA/D (A), or the ISP (B). The media were then removed and placed onto MKF for 24 h (C and D, respectively). Both the IFNAR1^−/− cells and MKF were treated with VSV. Cells were monitored for cell survival and stained with crystal violet at ∼18 h after infection. Each point represents the mean of triplicate wells.