HD5 and HD6 promote attachment of fluorescent Vpr-GFP-labeled virions to the target cells. Pseudotyped HIV-1JR-FL virus containing Vpr-GFP was incubated with or without HD5 and HD6 at 20 μg/ml at 37°C for 1 hour before addition to HeLa-CD4-CCR5 cells. After 2 hours incubation at 4°C, cells were extensively washed with cold-PBS, fixed, and analyzed by FACS (A) or microscopy (B). In panel A, the gray histogram represents the signal from samples without defensins, whereas the open histogram represents the signal from cells with exposure to defensin-treated fluorescent HIV. In panel B (magnification, 40X), white arrows indicate concentrated fluorescent HIV.