FIG 1.

P2X1 receptor antagonists specifically inhibit HIV-1 fusion irrespective of coreceptor tropism. HIV-1 fusion with TZM-bl cells (A to D) and CEM-A cells (E) was measured by a BlaM assay using HXB2 or BaL26 pseudoviruses containing BlaM-Vpr. Pseudoviruses bearing X4-tropic HXB2 (A and E), R5-tropic Bal26 (B), or dual-tropic R3A (C) HIV-1 Env or VSV-G (D) were prebound to cells in the cold and allowed to fuse for 90 min at 37°C. The fusion reaction was carried out in either the absence or the presence of the P2 receptor antagonists NF279 or NF449 (for P2X1R), NF340 (for P2Y11R), and A740003 (for P2X7R). The resulting BlaM signals were normalized to the signal for the untreated control. Data are means and standard deviations of results from three independent experiments carried out in triplicate. TZM-bl (A) or CEM-A (E) cell viability following virus-cell coincubation in the absence or in the presence of the highest tested concentrations of P2 receptor antagonists is shown (right of the axis break). Data are mean normalized 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay readouts and standard deviations from two independent experiments carried out in triplicate. ***, P < 0.001; NS, not significant.