Effect of CK666 on hypoxia-induced lactate production in T _eff . (A) Lactate production induced by hypoxia (1% oxygen) in T_eff in the presence or absence of 100 µM CK666 addition (5 mM glucose without serum). Circles indicate individual well measurements starting with 400,000 cells/well. n = 8 individual well measurements from four independent experiments. *** P = 0.0003; **** P < 0.0001. Statistical significance was calculated by two-way ANOVA using Tukey’s multiple comparisons test. (B) Lactate production induced by hypoxia (1% oxygen) in T_eff cells in the presence or absence of 100 µM CK666 addition (25 mM glucose without serum). Circles indicate individual well measurements starting with 400,000 cells/well. n = 8 individual well measurements from four independent experiments. n.s. P > 0.05; * P = 0.0136; **** P < 0.0001. Statistical significance was calculated by two-way ANOVA using Tukey’s multiple comparisons test. Number of experiments, statistical tests, and sample sizes are provided in Table S1.