Human PBMCs of two healthy donors were transiently transduced with lentiviral pseudovirions expressing a mixed pool of human IFITM shRNAs (IFITM1, 2 and 3) and the IFITM knockdown efficiency, in the presence or absence of IFNα2b, was assessed and confirmed by western blotting shown in Figure 4A. Single-round infection assays using inGLuc pseudotypes showed that in the absence of IFNα2b, knockdown of IFITMs in donor 1 and donor 2 (Figure 4B,C) modestly increased HIV-1 NL4.3 entry (~50%), yet more potently elevated entry of AD8 (~2–3-fold). This evidence concerns the gene IFITM1 and infection.