HD5 expresses in vaginal epithelial cells as precursor molecules that enhance HIV infection. A, Whole cell extracts from vaginal epithelial cells (lane 2) were prepared and analyzed by immunoblotting using polyclonal anti-HD5 Ab. Synthetic HD5 peptide (50 ng) was included in lane 1. B, Pseudotyped HIVJR-FL luciferase reporter virus was incubated with recombinant pro-HD5 proteins at different concentrations at 37°C for 1 h before addition to HeLa-CD4-CCR5 cells in the presence of 10% FBS. After 2 h of incubation, cells were washed and cultured in medium with 10% FBS for 48 h before measurement of luciferase activity. Difference between HIV-infected, untreated control, and samples with treatment of pro-HD5 at 10 or 50 μg/ml is significant; *, p < 0.05. Data are means ± SD of triplicate samples and represent two independent experiments. R.L.U., reflective light units.