Swine IFITM proteins potently inhibit influenza A virus replication

Human IFITMs were identified as restriction factors of influenza A virus (IAV). Given the important role of pigs in the zoonotic cycle of IAV we cloned swine IFITMs (swIFITM) and found two IFITM1-like proteins, one homologue of IFITM2 and one of IFITM3. We show that swIFITM2 and swIFITM3 localize to endosomes and display potent antiviral activity. Knockdown of swIFITMs strongly reduced virus inhibition by interferon establishing the swIFITMs as potent restriction factors in porcine cells