Impaired antiviral response in P117 MEFs and mice. (A) Wild-type, STAT1KO, and P117 MEFs were pretreated with 2-fold serial dilution of IFNα starting from 1000 U/ml for 24 h, followed by infection with EMCV at a M.O.I of 0.1. Live cells were visualized with crystal violet 18 h after the infection. Wild-type (squares) and P117 (triangles) mice were i.p. injected with 0.2 (B) or 200 (C) pfu/mouse of EMCV and survival rate was recorded every day for 7 days. Numbers in parenthesis represented live mice versus total mice at the end of the experiment.