IFNAR1 and infection: While MuV-NP RNA was significantly lower in Axl−/−Mer−/− than in WT cells in the absence of anti-IFNAR, the presence of anti-IFNAR increased MuV-NP RNA to comparable levels in both WT and Axl−/−Mer−/− Sertoli (Figure 7A, left panel) and Leydig (right panel) cells 48 h after MuV infection.