IFNAR1 and infection: Since the most common route of infection is via the respiratory tract, we also wanted to confirm the NK cell data after intranasal infection, and found that, although the effector molecule expression levels were quite low, the patterns were consistent with the splenic NK cell results, i.e. pulmonary NK cells from IFNAR−/− mice did not produce IFN-γ or granzyme B after i.n. inoculation with flu (Figure S3).