ISG15 and infection: Similar results were obtained for the IFN-stimulated gene (ISG), eukaryotic translation initiation factor 2-alpha kinase 2 (EIF2AK2), but not ISG15 and radical S-adenosyl methionine domain-containing 2 (RSAD2), which were significantly and highly upregulated in response to infection with DENV (p < 0.0001, Figure 2B).