CD4 and HIV-1 infection: We utilized the Triple-CD4ζ CAR that targets HIV-1 gp120 on the infected cell surface (27) with co-expression of two anti-HIV-1 shRNAs: sh1005 which suppresses surface expression of the key HIV-1 co-receptor CCR5 (40) and sh516 which prevents HIV-1 infection to both CD4+ T and CD8+ T cells mediated via CD4ζ expression (34).