P2X1 and P2X4 receptors contribute to NFAT activation and IL-2 expression of T cells. NFAT activation of Jurkat cells overexpressing wild-type (A) or mutated P2X1 or P2X4 receptors (B). NFAT activation (C) and IL-2 mRNA expression (D) of Jurkat cells after silencing of P2X1 or P2X4 receptors. Cell responses were assessed after stimulation with anti-CD3/CD28 antibody-coated beads for 8 hours. (E) IL-2 mRNA expression in Jurkat cells after combined silencing of P2X1, P2X4, and P2X7 receptors. (F) IL-2 mRNA expression in human PBMCs and mouse splenocytes stimulated for 4 hours in the presence or absence of P2X1 receptor–selective (NF023, 10μM), P2X1 and P2X4 receptor–selective (TNP-ATP, 30μM), P2X7 selective (A438079, 10μM), or nonselective (suramin, 100μM) P2 receptor antagonists. #P ≤ .05 compared with resting cells, *P ≤ .05, **P ≤ .01 compared with CD3/CD28- stimulated controls.