B18R is a type I interferon (IFN)-binding protein and it is encoded by the B18R open reading frame in the WR (Western Reserve) strain of vaccinia virus, which contains two Ig-like C2-type domains and one Ig-like V-type domain. B18R exists in a soluble and a membrane-bound form. As a type I IFN receptor, B18R counteracts the antiviral effects of host IFN-alpha/beta. Also, B18R acts as a soluble IFN-alpha receptor and thus inhibits the interaction between host IFN-alpha and its receptor. This protein is fused with a polyhistidine tag at the C-terminus, and has a calculated MW of 40.3 kDa. The predicted N-terminus is His 20. DTT-reduced Protein migrates as 50-60 kDa in SDS-PAGE due to glycosylation. Purity ≥95%