Plays a role in the inhibition of multiple cellular antiviral responses activated by dsRNA, such as inhibition of PKR activation, apoptosis, and IFN-mediated antiviral activities. Blocks also the phosphorylation and subsequent activation of IRF3 and IRF7 kinases that are required for interferon-alpha gene expression. Inhibits NF-kappa-B activation and the ubiquitin-like protein ISG15, which is an early antiviral protein. The binding with host ISG15 subsequently blocks host ISGylation. Inhibits ZBP1-dependent necroptosis via interaction with host ZBP1. Interacts with host G1P2/ISG15. Interacts with host EIF2AK2/PKR. Interacts with host ZBP1. Belongs to the poxviridae E3 protein family.