Reactive Intermediates in Leukocyte Systems

加州大学洛杉矶分校的C.Foote和R.Lehrer的这个项目是在生命过程化学计划的范围内进行的，该计划得到了化学部的有机动力学和细胞生物科学部的细胞生物学的联合支持。这项研究涉及白血球在防御感染中的作用。将努力了解有关在这一过程中如何利用氧气的细节。用化学方法表征人多形核白细胞(PMN)、嗜酸性粒细胞和巨噬细胞抗菌作用中的活性氯化物种和其他强氧化剂。将使用定量的三甲氧基苯测试来生产次氯酸，并将设计系统在这些细胞的内部和外部的指定位置捕获其他可能的氧化物种。将研究HOCl和其他氯化试剂的反应，以获得各种阳性氯物种的化学指纹。尽管HOCl或类似物可能是中性粒细胞(嗜酸性粒细胞中的HOBR)的主要氧气依赖型抗菌物质，但一个悬而未决的问题是巨噬细胞(缺乏PMN的MPO)和MPO缺乏的PMN杀死生物的机制。这一机制可能涉及单线态氧、其他活性氧物种或其他物质。单线态氧检测方法将进一步完善，并将开发检测其他活性物种的技术来解决这一问题。将尝试定量检测嗜酸性粒细胞中的单线态氧，并进一步改进卤素分析。单线态氧、卤素和其他共价结合到易吞噬的聚合物微珠上的化学探针应该为白细胞吞噬空泡提供有用的、可定位的探针。这应该可以回答是否所有的氧化剂都是在吞噬小泡中产生的，或者是否有一些逃逸到了介质中。

This project by C. Foote and R. Lehrer of UCLA is within the Chemistry of Life Processes Program, jointly supported by Organic Dynamics of the Chemistry Division and Cell Biology of the Division of Cellular Biosciences. This work deals with the role of white blood cells in the defense against infection. Efforts will be made to learn the details about how oxygen is utilized during this process. The active chlorinating species and other strong oxidants in the antimicrobial action of human polymorphonuclear leukocytes (PMNs), eosinophils and macrophages will be characterized by chemical means. A quantitative trimethoxybenzene assay will be used for the production of hypochlorous acid, and systems will be designed to trap other possible oxidizing species in defined locations in both the interior and exterior of these cells. Reactions of HOCl and other chlorinating agents will be studied to obtain chemical fingerprints for various positive chlorine species "in vitro" and in cells. Although it is likely that HOCl or a similar species is the major oxygen-dependent antimicrobial species of the neutrophil (HOBR in the eosinophil), an unresolved problem is the mechanism by which macrophages (which lack the MPO of PMNs) and MPO-deficient PMNs kill organisms. This mechanism might involve singlet oxygen, other active oxygen species, or something else. Singlet oxygen detection methodology will be further refined, and technology will be developed for the detection of other reactive species to attack this problem. Attempts to detect singlet oxygen quantitatively in eosinophils and further improvements on the halogen assay will be made. Chemical probes for singlet oxygen, halogens, and other species which are covalently bonded to readily-phagocyzed polymer microbeads should provide useful, localizable probes for the white-cell phagocytic vacuole. This should allow an answer to the question of whether all the oxidant is produced within the phagocytic vesicle or whether some escapes to the media.