Study of the mechanism of ozone production and application for enhancement of bactericidal activity in human neutrophils

中性粒细胞吞噬产生的活性氧是一把双刃剑。它们在宿主的先天防御中起着关键作用，同时也会造成组织损伤。活化的中性粒细胞通过NADPH氧化酶活化产生ROS，如超氧化物、过氧化氢、羟基自由基和单线态氧。最近有报道称，免疫球蛋白具有催化单线态氧生成臭氧的活性。然而，确切的机制和在宿主防御中的作用仍不清楚。在这项研究中，我们发现4种氨基酸本身能够催化从单线态氧产生具有臭氧化学特征的氧化剂，其水平与免疫球蛋白相当。我们还发现，氨基酸产生的臭氧有助于杀死人体中性粒细胞中的细菌。

Reactive oxygen species (ROS) by phagocytosing neutrophils are double-edged swords. They play a pivotal role in innate host defense, while they bring about tissue injury. Activated neutrophils produce ROS via NADPH oxidase activation, such as superoxide, hydrogen peroxide, hydroxyl radical, and singlet oxygen. It has been recently reported that immunoglobulin has a catalytic activity to produce ozone from singlet oxygen. However, the precise mechanism and the role in host defense remain unclear. In this study, we discovered that 4 amino acids themselves were able to catalyze the production of an oxidant with chemical signature of ozone from singlet oxygen at comparable level of immunoglobulin. We also revealed that ozone production by amino acids contributed to killing of bacteria in human neutrophils.