Fig. 2.

Effect of viperin on the peripheral type I IFN response after WNV infection. Viperin^−/− and wild-type mice were inoculated with 10² PFU of WNV by subcutaneous injection into the footpad. At the indicated times postinfection, serum was collected, and type I IFN activity was determined by an encephalomyocarditis virus cytopathic effect bioassay with L929 cells. The dotted line indicates the limit of detection of the assay, and data representing 5 to 15 mice at each time point are expressed as the average values on a log₁₀ scale. Asterisks indicate differences that are statistically significant by the Mann-Whitney test (*, P < 0.05), which was performed on linear IFN levels.