FIG. 6.

Ability of the NS1 and NS2 proteins to independently block the induction of expression of mRNA encoding IFN-α set 1 (a), IFN-α set 2 (b), or IFN-β (c) in A549 cells in response to superinfection by the ΔNS1/2 virus. Triplicate sets of cells were infected with wt rA2, ΔNS1, ΔNS2, or ΔNS1/2 or were mock infected and were incubated for 8 h. One culture from each set was processed to purify intracellular RNA, and the remaining cultures were mock superinfected or superinfected with ΔNS1/2. The cultures were incubated for an additional 12 h and processed to purify intracellular RNA. The expression levels of IFN mRNA were measured by qRT-PCR.