FIG 9.

PRV deficient in UL50 is more sensitive to IFN-α-mediated viral inhibition. (A) PK15 cells were treated with porcine IFN-α (1,000 U/ml). Twenty-four hours later, the cells were infected with either wild-type PRV or recombinant PRV-UL50 KO for 1 h (MOI = 0.1). The infected cells were then incubated in medium containing porcine IFN-α (1,000 U/ml) for an additional 24 h. The cells were harvested and lysed for Western blotting (left) and TCID₅₀ assay (right). (B) CRL cells were treated with porcine IFN-α (500 U/ml). Twelve hours later, the cells were infected with either PRV-WT or recombinant PRV-UL50 KO for 1 h (MOI = 1). The infected cells were then incubated in medium containing porcine IFN-α (500 U/ml) for an additional 24 h. Cells were harvested and lysed for Western blotting (left) and TCID₅₀ assay (right). The virus protein (US3 and UL50) levels were examined by Western blotting, and tubulin was included as a loading control. The results were obtained from three independent experiments and are means and SD. Statistical analyses were performed by ANOVA, using GraphPad Prism software. **, P < 0.01; ***, P < 0.001.