IFNAR1 and infection: Previous studies in mouse models using PV, CVB, and EV71 have shown that the ablation of type I interferon (IFN) signaling by the deletion of the IFN-α/β receptor (IFNAR) is required for infection by the oral route (11, –, 16), suggesting that these IFNs play a central role in the protection of the GI tract from enterovirus infection.