One group of ISGs, as represented by several well-known anti-influenza ISGs (Gbp3, Ifit3, Isg15, and Mx1/2), showed a kinetic pattern of mRNA expression largely resembling that of IFN-γ mRNA, suggesting that they were likely to be directly regulated by IFN-γ in an autocrine manner. This evidence concerns the gene ISG15 and influenza.