Transduction titers on the FAT10-, IDO1-, and IFI6-expressing HeLa cells (HeLa/FAT10, HeLa/IDO1, and HeLa/IFI6 cells) were much lower than those on the control cells, showing that FAT10, IDO1, and IFI6 significantly inhibit amphotropic MLV-pseudotyped HIV-1-based vector infection. This evidence concerns the gene IDO1 and infection.