IFNAR1 and infection: The knockout of the IFN-λ receptor (subunit IFNLR1), compared to the knockout of the IFN-β receptor (subunit IFNAR1), only slightly influences levels of STAT1/2 phosphorylation during infection with any of the viruses; However, IFNLR1 knockout results in a greater proportion of IAV-infected cells and higher viral RNA and protein levels.