Activation and Up-regulation of Phospholipase D Expression by Lipopolysaccharide in Human Peripheral T Cells

Eileen Jea Chien ； Chien-Ching Chen ； Chau-Heng Chien ； Tzu-Pei Yeh ； Li-Ming Lu

《The Chinese Journal of Physiology》 47卷4期 (2004/12) Pp. 203-209

並列摘要

In a previous study, we showed that bacterial LPS activates protein kinase C (PKC) and causes an intracellular pH (pH(subscript i)) increase, but does not elevate intracellular calcium ([Ca(subscript 2+)](subscript i)) in human peripherial T cells. Hence this study aimed to investigate whether the activation of PKC was resulted from phospholipase D (PLD) catalysis by LPS. The activity of PLD was measured by the production of (superscript 3)H- phosphatidylethanol from phosphatidic acid (PA), and the expression of PLD or IL-2 Rα was determined by reverse transcription-polymerase chain reaction (RT-PCR) analysis. Enzyme-linked immunosorbent assay (ELISA) was used to analyze IL-2 and IL-4. Phytohemagglutinin (PHA), and phorbol 12-myristate 13-acetate (PMA) were used as controls. Our results indicated that (1) LPS-stimulated pH(subscript i), elevation was PKC dependent; (2) After 30 min stimulation, LPS increased PLD activity via a measured production of (superscript 3)H-phosphatidylethanol from phosphatidic acid and the initiation of PLD1a mRNA expression started; (2) LPS stimulated IL-2 R expression but not IL-2 and IL-4 secretion. Our findings suggested that the stimulation of PLD activity and its mRNA expression by LPS might be required for IL-2 R expression and a sustained PKC dependent pH(subscript i) elevation but not for the secretion of IL-2 or IL-4 in human T cells. This indicated that LPS might enhance T cell adaptive immunity to resist Gram-negative bacterial infection.

並列關鍵字

LPS ； pH(subscript i) ； phospholipase D ； T cells

參考文獻

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