IFNLR1 and infection: (A) Standard intranasal delivery of virus inoculum: WT (n = 6), Ifnar1−/− (n = 4) and Ifnlr1−/− (n = 7) mice were intranasally infected with 104 PFU of SC35M in a volume of 40 μl, and viral titers in the lungs were determined on day three post infection by plaque assay.