IFITM3,also named as interferon-inducible protein 1-8U,belongs to the CD225 family. It is IFN-induced antiviral protein that mediates cellular innate immunity to at least three major human pathogens,namely influenza A H1N1 virus,West Nile virus (WNV),and dengue virus,by inhibiting the early steps of replication. IFITM3 is identified as interferon-induced cellular proteins that restrict infections by retroviruses and filoviruses and of influenza virus and flaviviruses,respectively. IFITM3,the most potent antiviral IFITM,was found to inhibit an uncharacterized early infectious event after VSV endocytosis,but before primary transcription of its viral genome. IFITM proteins are viral restriction factors that can inhibit infection mediated by the influenza A virus (IAV) hemagglutinin (HA) protein. They differentially restrict the entry of a broad range of enveloped viruses,and modulate cellular tropism independently of viral receptor expression. This antibody recognizes both IFITM2 and IFITM3.