STAT1 and infection: In order to determine whether the reduced levels of STAT1 in IFNAR1−/− cells could affect biological responses to IFNγ, we investigated whether re-expression of STAT1 in IFNAR1−/− cells impacted upon the ability of IFNγ to protect them against infection by the cytopathic virus murine encephalomyocarditis virus (EMCV).