During viral infection, ISGF3 plays an important role in inducing promoters containing the IFN-stimulated response element (ISRE)—thus upregulating antiviral IFN-stimulated genes (ISGs), including 2′,5′–oligoadenylate synthetase (OAS) and protein kinase R (PKR). This evidence concerns the gene EIF2AK2 and viral infectious disease.