Induction and suppression of type I interferon responses by mink enteritis virus in CRFK cells

•MEV neither induced nor was sensitive to the effects of type I interferon.•The nonstructural protein (NS1) of MEV inhibits IFN induction.•The ORI-binding domain of NS1 protein suppresses IFNβ expression. Mink enteritis virus (MEV) is one of the most important viral pathogens causing serious disease in mink. Type I interferon (IFN) plays a critical role in antiviral innate immunity and, for successful infection, many viruses have evolved evasive strategies against it. Here, we show that MEV infection does not evoke IFN or interferon-stimulated genes (ISGs) responses in feline kidney (CRFK) cells, and that MEV suppresses IFN production in both poly I:C-stimulated and untreated cells. In CRFK cells pre-exposure to IFN, show that infection with, and replication of, MEV remain unaffected. This inhibition appears to be mediated by the MEV nonstructural protein (NS1) with its ORI-binding domain playing a major role.