Fig. (3) Binding inhibition of HIV-1 to epithelial cells by hLF and LF-33 peptide. HEC-1 (A and C) and HT-29 (B and D) cells (10⁶ cells) were incubated with HIV-1_JR-CSF and HIV-1_NDK particles (5 ng/ml of p24 antigen) for 1 h at 37°C. After washes, adsorbed virus was treated by Triton and p24 antigen was measured by ELISA. Cells were pre-incubated with hLF (A and B), LF-33 peptide (C and D) or an irrelevant peptide control (not shown) for 30 min at room temperature before virus addition. Results are represented as percentage of the control (performed without pre-incubation of cells with hLF or LF-33 peptide), and corresponds to the mean ± SD from 3 independent experiments. In experimentations, 10 µg/ml of hLF and LF-33 peptide corresponded to 128 nM and 2.5 µM, respectively.