HD5 inhibits HIV-1 envelope-mediated fusion induced by clinical and laboratory HIV-1 isolates with different coreceptor usage.
Fusion assays were performed using the human T-cell line (PM1) chronically infected with two prototypic laboratory-adapted strains (HIV-1IIIB and HIV-1BaL) and four primary clinical isolates (R5: HIV-1J6366 and HIV-1J2615; X4: HIV-1J57 and HIV-1J287) cocultured with NIH-3T3 cells expressing membrane-bound CD4 and either CCR5 or CXCR4 in the presence or absence of increasing concentrations of HD5 (filled circles) for 2 hrs at 37°C in medium without FCS. For comparison, inhibition by HNP1 (open squares) used at the same concentrations is shown. The data are normalized with respect to fusion observed in the absence of inhibitors. The data represent mean values (±SD) from 3 experiments.