ISG15 and infection: The common pathways upregulated upon infection by each of these three viruses included innate antiviral and inflammatory pathways, such as OAS and ISG15-mediated antiviral responses, interferon α/β signaling, cytokine and interleukin signaling, NOD1/2 signaling, and the NLRP3 inflammasome pathway (Fig 1H; S2 Table).