IFN-α/β inhibits WNV infection in neurons. Primary cultures of SCG neurons were prepared from wild-type and IFN-α/βR−/− mice. (A) Neurons were pretreated 24 h prior to infection with 100 IU/ml of the indicated mouse IFN. Cells were infected at an MOI of 10 and evaluated for production of infectious WNV at 24 h. (B) Neurons were infected at an MOI of 10 for 24 h, treated with 100 IU/ml of the indicated mouse IFN for 12 h, washed, and then evaluated for WNV production at 48 h. Data represent an average of three independent experiments, and asterisks indicate values that are statistically significant (*, P < 0.05) compared to untreated cells.