Myeloperoxidase is more efficient than eosinophil peroxidase in the in vitro killing of newborn larvae of Trichinella spiralis.
Myeloperoxidase is more efficient than eosinophil peroxidase in the in vitro killing of newborn larvae of Trichinella spiralis.
复制标题
髓过氧化物酶在体外杀灭旋毛虫新生幼虫方面比嗜酸性粒细胞过氧化物酶更有效。
作者：
J. Buys;R. Wever;E. Ruitenberg
髓过氧化物酶 (MPO) 和嗜酸性粒细胞过氧化物酶 (EPO) 催化氯离子 (OCl-) 和过氧化氢 (H2O2) 形成次氯酸盐 (OCl-)。体外试验证明 OCl- 对旋毛虫新生幼虫 (NBL) 有剧毒。使用纯化的人 MPO 和 EPO，发现即使在中性 pH 值下，这两种酶在适当的条件下也能够杀死 NBL。 EPO- 中产生 OCl- 的速率比 MPO 介导的反应低得多。酶活性的这种差异可以解释为什么在 MPO 介导的反应中，与 EPO 介导的反应相比，一半的 OCl- 足以杀死 50% 的 NBL。纯化的人嗜酸性粒细胞主要碱性蛋白显示出优异的 OCl 清除特性，导致 EPO 介导的 NBL 杀伤显着减少。在 EPO 介导的反应中添加铵离子 [(NH4)2SO4] 显着增加了 NBL 的杀灭作用。结论是体外MPO比EPO更有效地杀灭NBL。此外，有人提出，尽管嗜酸性粒细胞在各种体外系统中显示出显着的杀寄生虫作用，但它们的主要生物学作用可能是调节炎症反应。
Myeloperoxidase (MPO) and eosinophil peroxidase (EPO) catalyse the formation of hypochlorite (OCl-) from chloride ions (OCl-) and hydrogen peroxide (H2O2). OCl- proved to be highly toxic for Trichinella spiralis newborn larvae (NBL) in in vitro assays. Using purified human MPO and EPO it was found that even at neutral pH both enzymes under appropriate conditions are able to kill NBL. The rate at which OCl- is produced is much lower in the EPO- than in the MPO-mediated reaction. This difference in enzymic activity may explain why in the MPO-mediated reaction half the amount of OCl- was sufficient to kill 50% of the NBL, as compared to the EPO-mediated reaction. Purified human eosinophil major basic protein showed excellent OCl- scavenging properties, resulting in a significant decrease in the EPO-mediated NBL killing. Addition of ammonium ions [(NH4)2SO4] to the EPO-mediated reaction increased the NBL killing remarkably. It was concluded that in vitro MPO is more efficient than EPO in killing NBL. Furthermore, it was suggested that although eosinophils show marked parasiticidal effects in various in vitro systems, their primary biological role might be the regulation of the inflammatory reactions.