ITIH4 and HIV-1 infection: However, KD of HEAL had no significant effect on IFI6 expression (Fig. 2G), indicating that IFI6 was not the functional target of HEAL. Next, we examined the effects of lentivirus-mediated overexpression of HEAL on HIV-1 infection in MT4 cells by examining GP120 expression 2 days after HIV-1 infection.