EFFECT OF INTRACELLULAR REDOX STATUS ON IMMUNOLOGICALLY COMPETENT CELLS : APPLICATION OF THE INDICATOR FOR EVALUATION OF OXIDATIVE STRESS

本研究旨在探讨免疫活性细胞的信号转导与细胞内氧化还原状态之间的关系，即活性氧化中间产物(ROI)的形成与机体对氧化应激的防御能力之间的平衡关系，并建立外源性氧化应激对免疫功能破坏的评价体系。当人T细胞白血病(Jurkat)和早幼粒细胞白血病(HL-60)细胞株同时暴露于浓度小于50μ的过氧化氢(H_2O_2)引起轻度氧化应激时，仅在后者的细胞中检测到ROI。这一结果表明，即使受到相同程度的氧化应激，两种细胞系之间的氧化还原状态也存在差异。在HL-60细胞中，H_2O_2诱导的细胞存活率下降，这是由细胞凋亡引起的。当细胞暴露于一定浓度的H_2O_2诱导细胞凋亡时，观察到肿瘤坏死因子α的产生。检测水平的肿瘤坏死因子-α处理也可诱导细胞凋亡。这些结果表明，羧基-DCFH-DA流式细胞术能够检测细胞内ROI的形成，而ROI的形成伴随着细胞凋亡的诱导和肿瘤坏死因子-α的形成。

This study was conducted to investigate about relationship between signal transduction in immunologically competent cells and the intracellular redox status that is in a balance on the formation of reactive oxidant intermediates (ROI) and the defense ability against oxidative stress and also to develop an evaluation system for immune disruption by exogenous oxidative stress. When both human cell lines, T-cell leukemia (Jurkat) and promyelocytic leukemia (HL-60) were exposed to hydrogen peroxide (H_2O_2) at the concentration of less than 50 μmol/L that causes mild oxidative stress, ROI was detected by carboxy-DCFH-DA flow cytometry only in the latter cells. This result indicated that there was a difference in redox status between both cell lines even though the same extent of oxidative stress was suffered. In HL-60 cells, viability was decreased by H_2O_2 exposure and this was caused by apoptosis. Production of TNF-α was observed when the cells were exposed to the concentration levels of H_2O_2 that caused apoptosis. Treatment of TNF-α at the detection levels also resulted in the induction of apoptosis. These results suggest that carboxy-DCFH-DA flow cytometry is capable to detect the formation of intracellular ROI which is concomitant with apoptosis induction and TNF-α formation.