Figure 7. Ecto-ATPase activity on human iNKT cells.

CD4⁺ NKT cells (50,000) in triplicate wells were cultured with or without αCD3/αCD28 Dynabeads for 48 hours at 37°C and assayed for ecto-ATPase activity as described in the Methods. Vehicle or CD39 inhibitor (50 μM POM1) was added to wells before luciferase plus luciferin followed by 10 μM ATP. Luminescence from each well was measured repetitively at room temperature on a SpectraMax M2 plate reader at various times after addition of ATP. The results are representative of 5 experiments.