FIG. 3.

Inhibition of OAS activity in HSV-1-infected cells requires late gene expression. (A) IE gene expression is not sufficient to completely inhibit OAS activity. NHDF cells treated with IFN-α (1,000 IU/ml for 24 h) or untreated were either mock infected or infected (MOI of 5) with the indicated HSV-1 mutant strains. At 10 h postinfection, soluble extracts were prepared and their OAS activity was evaluated in the presence of increasing concentrations of dsRNA activator. Reaction products were processed as described in the legend to Fig. 2. (B) NHDF cells (untreated or treated with 1,000 IU/ml IFN-α for 24 h) were either mock infected or infected with wild-type HSV-1 (Patton strain). Cultures were treated with PAA (300 μg/ml) as indicated, and OAS activity was evaluated in the presence of 0.1 μg/μl of poly(I)(C).