Figure 5.

LPS-induced ATP release impairs T cells via P2Y11 receptors. A, scavenging of extracellular ATP restores T cell migration and proliferation. CD4 effector T cells were exposed to exogenous ATP (10 μm; left), and PBMCs were stimulated with LPS (100 pg/ml) and anti-CD3 antibodies (right) in the presence or absence of apyrase (1 microunit/ml). T cell migration was assessed by time-lapse microscopy, and CD4 T cell proliferation was measured with flow cytometry after 3 days. Data are means ± S.D. (error bars) of n = 5 experiments (left; each experiment comprising the analysis of at least 20 individual cells) or n = 4 experiments (right). *, p < 0.05, one-way ANOVA. B, stimulation of P2Y11 receptors by exogenous ATP blocks T cell migration. CD4 effector T cells exposed to exogenous ATP (10 μm) were treated with selective antagonists of P2X4 (5-BDBD; 10 μm) or P2Y11 (NF340; 10 μm) receptors, and T cell migration was assessed by time-lapse microscopy. Data are means ± S.D. of n ≥ 4 separate experiments, each comprising the analysis of at least 20 individual cells. *, p < 0.05, one-way ANOVA. C and D, LPS and exogenous ATP impair T cell activation via P2Y11 receptors. PBMCs were pretreated with the P2Y11 receptor antagonist NF340 (100 nm), exposed to exogenous ATP (100 μm) or LPS (10 ng/ml), and stimulated with anti-CD3 antibodies, and IL-2 production was determined after 18 h. Data represent mean ± S.D. of n ≥ 6 experiments. Values are corrected for the effect of inhibitors alone. *, p < 0.05 versus control (one-way ANOVA or Kruskal–Wallis test).