IFITM1 and viral infectious disease: Various studies have demonstrated that ISG15, 2′-5′ oligoadenylate synthase (OAS2), double-stranded RNA protein kinase R (PKR), interferon-induced transmembrane protein 1 (IFITM1), and nitric oxide synthase (NOS) play a crucial role in inhibiting viral infections (Knapp et al., 2003; Lowenstein and Padalko, 2004; Silverman, 2007).