Interferon omega-1 is also known as Interferon alpha-II-1and IFNW1. It is a Secreted protein that in humans is encoded by the IFNW1 gene. IFNW1 belongs to the alpha/beta interferon family. Type I IFNs consist of IFN α, β, τ, and ω and bind to the type I IFN receptor, whereas IFN-γ is the only type II IFN and is specific for the type II IFN receptor. IFNW1 is a recently discovered protein structurally related to IFN-alpha and –beta. It has been shown that IFN-omega 1 similar to that of other human class I IFNs; potent antiviral activity was also observed on cells of bovine and ovine but not of equine or murine origin.