CD74 Interacts with Proteins of Enterovirus D68 To Inhibit Virus Replication

Enterovirus D68 (EV-D68) is a member of the species Enterovirus D in the genus Enterovirus of the family Picornaviridae. As an emerging non-polio enterovirus, EV-D68 is widely spread all over the world and causes severe neurological and respiratory illnesses. Although the intrinsic restriction factors in the cell provide a frontline defense, the molecular nature of virus-host interactions remains elusive. Here, we provide evidence that the major histocompatibility complex class II chaperone, CD74, inhibits EV-D68 replication in infected cells by interacting with the second hydrophobic region of 2B protein, while EV-D68 attenuates the antiviral role of CD74 through 3C^pro cleavage. 3C^pro cleaves CD74 at Gln-125. The equilibrium between CD74 and EV-D68 3C^pro determines the outcome of viral infection. IMPORTANCE As an emerging non-polio enterovirus, EV-D68 is widely spread all over the world and causes severe neurological and respiratory illnesses. Here, we report that CD74 inhibits viral replication in infected cells by targeting 2B protein of EV-D68, while EV-D68 attenuates the antiviral role of CD74 through 3C^pro cleavage. The equilibrium between CD74 and EV-D68 3C^pro determines the outcome of viral infection.