Figure 3.

a. HIV-1 env mediated cell-cell fusion inhibition assay. Cells expressing the HIV-1 envelope were incubated with target cells expressing HIV receptors in the presence of recombinant peptides P5 (black triangle), P1 (black square), P5L (black diamond) and P7 (x), and compared with peptide T20 (open circle). After 6 h of co-culture, fusion was quantified by measuring the beta–galactosidase activity after lysis of the cells. The values were expressed as the average (± S.D.) of three wells from one representative experiment of three. b. Inhibition of human PBMC infection by HIV-Lai in the presence of P1, P5 and T20. Inhibition of PBMC infection by HIV-Lai was evaluated by intracellular staining of p24 Ag. At 1 μM, peptides P5 and T20 exhibited potent inhibition of PBMC infection by X4 virus. In contrast, P1, a shorter peptide devoid of the gp41calcium-binding site, did not inhibit PBMC infection at the same concentration. c. Inhibition of human PBMC infection by HIV-_JRCSF in the presence of P1, P5 and T20. Percent of inhibition of PBMC infection by HIV-_JRCSF evaluated as in Figure 3b by intracellular staining of p24 Ag. Inset: IC50 are given in nM.