FIG. 6. .

Vaccinia infection blocks interferon-λ (IFN-Δ)–mediated STAT phosphorylation and gene expression. A549 cells were infected with VACV for 1 h (MOI = 5) prior to treatment with 2.5 ng IFN-α/mL or 5 ng IFN-λ1/mL. Cells were harvested for (A) Western blot analysis of STAT-1 phosphorylation 1 and 4 h post-treatment or (B) quantitative RT-PCR analysis of IFN-stimulated gene expression 4 h post-treatment. Graph bars represent the mean of 3 independent experiments, and error bars indicate SEM.