We found that IFN-γ, but not IFN-I, was highly upregulated in OBs early after infection, but surprisingly found that, unlike IFN-I, IFN-γ was required for the efficient replication of JHMV in mice, as JHMV WT and N1347A replication was dramatically reduced in IFN-γ−/− and IFN-γR−/− mice. This evidence concerns the gene IFNGR1 and infection.