FIG 6.

The P2X1R inhibitor NF279 acts as a dual CXCR4/CCR5 antagonist. Calcium influx was induced upon CXCR4 and CCR5 activation with 25 nM SDF-1α and 300 nM RANTES, respectively, in TZM-bl cells (A and B) and CEM-A cells (C and D). Cells were loaded with the calcium indicator Fluo4 and imaged in complete medium for ∼1 min prior to the addition of chemokines in the absence or in the presence of 30 μM the P2 receptor antagonist NF279 or NF340 (arrows). In control experiments, SDF-1α and RANTES were applied together with 7 μM the CXCR4 antagonist AMD3100 or the CCR5 antagonist TAK-779 (see also Movies S1 and S2 in the supplemental material). Alternatively, CXCR7 on CEM-A cells was activated with 60 nM I-TAC in the absence or in the presence of NF279 (D). The curves represent the mean fluorescence intensities of TZM-bl (n = 50) or CEM-A (n = 70) cells normalized to the fluorescence signal after the addition of A23187 (2.5 μM) from three experiments conducted in triplicate (± standard deviations).