GFP expression in human dendritic cells infected with pRSVGFP and Ad5RSVGFP in the absence and the presence of cationic liposomes. Cells in the gated region (Fig 2A) were analyzed for GFP fluorescence. They were untreated (A), treated with pRSVGFP in the absence (B) and in the presence of liposomes (C), or infected with Ad5RSVGFP in the absence (D) and in the presence of liposomes (E).