ISG15 and HIV-1 infection: We also noted that HIV-1 infection induces a prominent antiviral state in early/mid-gestation HCs, characterized by transcription and secretion of IFN-α and significantly elevated transcription of the RLRs, STAT1, STAT5, ISG15, OAS1, IFIT1, IFIT2, IFIT3, and Viperin.