Single-cycle HIV-1 infection was reduced by more than 100-fold in IFN-I-primed ISG15-deficient cells compared to unprimed ISG15-deficient cells, while only a modest 2.8-fold difference was observed in WT IFN-primed cells compared to WT unprimed cells (Fig 1B). This evidence concerns the gene IFNA1 and HIV-1 infection.