IFITM1(interferon induced transmembrane protein),also named DSPA2a and interferon-induced protein 17 (IFI17),belongs to the CD225 family. It has two transmembrane domain and serves as an IFN-induced antiviral protein that mediates cellular innate immunity to at least three major human pathogens,influenza A H1N1 virus,West Nile virus (WNV),and dengue virus ,by inhibiting the early steps of replication. IFITM proteins are recently identified as viral restriction factors that inhibit infection mediated by the influenza A virus (IAV) hemagglutinin (HA) protein. Also they serve as important components of the innate immune system to restrict HIV-1 infection. This antibody is a mouse monoclonal antibody which specifically recognizing IFITM1 but not IFITM2 or IFITM3.