FIG. 2.

Effects of extracellular ATP on the activity of mycoplasmal lipopeptides to induce TNF-α production by THP-1 cells. THP-1 cells (10⁶ cells/ml) were treated at 37°C for 1 h with 10 nM FSL-1 or 50 nM MALP-2 or not treated, and then ATP was added to the culture at the indicated concentrations. After an 8-h incubation period, the culture supernatant was collected and assayed for the amount of TNF-α by ELISA. Results, expressed as the means ± standard deviations (SD) of values for triplicate wells, are representative of three separate experiments. Statistical significance of augmentation by ATP, compared with the ATP-nontreated cells (open bars), was analyzed by t test. ∗, P < 0.05; ∗∗, P < 0.01.