Expression of P2X receptors by human T cells. (A) P2X receptor mRNA expression in Jurkat cells and human peripheral CD4⁺ T cells determined by real-time reverse transcriptase PCR analysis. (B) Immunocytochemical assessment of P2X1 and P2X4 receptor expression of Jurkat cells and human primary CD4⁺ T cells evaluated by fluorescence microscopy. (C) P2X1 and P2X4 receptor mRNA expression levels of Jurkat cells in response to stimulation by PHA (50 ng/mL) and PMA (5 ng/mL). (D) Immunoblotting of P2X1 and P2X4 receptors before and after stimulation of Jurkat cells with PHA (50 ng/mL) and PMA (5 ng/mL). Data represent means ± SEM from triplicate experiments.