Innate immunity to VV is dependent on TLR-independent induction of IFN-β. (A) Innate antiviral defense. VV (1 × 10⁷ pfu) was injected intraperitoneally into female, wild-type 129/Sv mice (WT) or IFN-αβR^−/− mice on 129/Sv background (IFN-αβR^−/−). Ovaries were harvested 3 days after administration of virus and measured for viral load by plaque-forming assay. Data represent viral titer as plaque-forming unit (pfu) per ovary. (B) Cytokine production. WT or IFN-αβR^−/− mice were administered intravenously with 1 × 10⁷ pfu VV, and serum samples were harvested 6 hours later for the measurement of IL-6 and IFN-β by ELISA. Error bars indicate SD.