HIV-1 gp120 up-modulates PC-PLC enzymatic activity in MDMs. Monocytes were seeded and cultured as described in “Methods.” At day 7, cells were treated as follows: (A) with different concentrations of R5 gp120 (0.3, 1, 3 μg/mL) for 5 minutes; (B) with D609 (50 μg/mL) for 30 minutes prior to gp120 exposure (3 μg/mL) for 5 minutes. Cells were then lysed and PC-PLC enzymatic activity was measured in cell lysates as described in “Methods.” In panel A, the relative contribution of PC-PLD was subtracted to the total fluorescence. In panel B, PC-PLC and PC-PLD activities are shown separately. Data shown in panels A and B are the means (± SD) of the results obtained with 4 different donors. *P < .05; **P < .005.