FIG. 5.

Involvement of the calcium pathway. (A) Effect of calcineurin inhibitor cyclosporin A (Cs A) and of the chelator of intracellular calcium BAPTA/AM on the Tat-induced production of IL-10. Monocytes were treated or not for 30 min as indicated and then treated or not with Tat at 10 nM. Culture supernatants were recovered, and the presence of IL-10 was determined by ELISA. (B) Positive control of inhibition by cyclosporin A and BAPTA/AM on the ionomycin-induced production of TNF-α. Monocytes were treated or not for 30 min as indicated and then treated or not with ionomycin (1 μM) for 24 h. Culture supernatants were then collected, and the presence of TNF-α was determined by ELISA. These results are representative of three independent experiments done on cells from two donors. (C and D) Variations in intracellular calcium concentrations determined by microspectrofluorimetry using fluo-3AM as the probe. Cells were incubated for 30 min in the presence of fluo-3 (5 μM) and observed microscopically after two washes. Monocytes were stimulated by 100 nM Tat (C) or 1 μM ionomycin (D). The curves are the results obtained from the means for 11 different cells from a single donor. Similar results were obtained with cells from two different donors.