FIG. 1.
Single-cycle multiplication of ΔE3L mutant compared to WT vaccinia virus in PKR+, PKRkd, and PKRkd-con HeLa cells. WT parental (PKR+), PKR-deficient knockdown (PKRkd), and PKR-sufficient control knockdown (PKRkd-con) HeLa cells were mock treated or treated with 1,000 IU/ml of IFN-αA/D (α) or IFN-β (β) for 24 h. (A) Western blot analysis comparing PKR expression levels. Whole-cell extract protein (10 μg) was analyzed in each lane; the membrane was probed with antibody against human PKR and antibody against β-actin as a loading control. (B) Virus yields. Cells were infected with either WT or ΔE3L virus at an MOI of 5. At 24 h p.i., cells were harvested and virus yields were determined by plaque titration on RK13 cells. The results shown are the means ± standard deviations determined from a minimum of three experiments.