B8R Products

B8R is a secreted Interferon gamma binding protein encoded by the open reading frame of the Vaccina virus (smallpox). B8R binds IFN--gamma orthologs from multiple species including human, rat, rabbit, bovine, and chicken with high affinity, but it binds mouse IFN-gamma with low affinity. During infection, virally-induced B8R binds and sequesters endogenous IFN-gamma, thereby suppressing the host immune response and promoting viral immune evasion. While B8R is not required for viral replication, it contributes significantly to Vaccinia virus virulence and is frequently inactivated prior to Vaccinia use in vaccines.