ISG15 and Zika virus infectious disease: With this in mind we investigated the role that ZIKV infection has in induction of antiviral gene expression by measuring the induction of IFN-β and a panel of ISGs (viperin, IFIT1, IFITM1, ISG15, OAS and Mx1) at various time points following infection using physiologically relevant cell lines of placental and neurological origin.