MECHANISM OF ACTION OF C PERFRINGENS ENTEROTOXIN

产气荚膜梭菌肠毒素(CPE)是近年来出现的 胃肠道重要细菌毒力因子(G.I.)疾病。 有令人信服的流行病学证据表明CPE参与了 最常见的人类食物中毒之一；最近的研究也将 CPE阳性产气荚膜梭菌对其他严重人类胃肠道的影响 疾病和婴儿猝死综合症。CPE对人体有独特的作用 哺乳动物的膜，这是区别于所有其他已知的毒素。 CPE行动的每一步都涉及CPE与 哺乳动物的膜蛋白。 本项目的长期目标是了解CPE的作用 (和CPE阳性菌株)；这些研究可能最终 确定预防或治疗CPE相关疾病的策略。至 为实现这一目标，提出了以下具体目标：1) 检验最近的一种假设，即50 kDa的膜蛋白作为一种 功能性CPE受体(CPE与CPE受体的结合是 细胞毒性所必需)使用“抗受体抗体”CPE结合 CPE受体的抑制研究和克隆，2)进一步澄清 CPE作用通过a)确定CPE在膜中的拓扑取向 以及b)使用两种生物化学方法剖析CPE行动中的个别事件 和超微结构技术，3)高分辨率MAP CPE功能 区域(并最终将此信息与CPE结构数据相结合) 确定CPE分子如何参与细胞毒作用和4) 通过研究剖析CPE阳性分离株的分子发病机制 CPE(可能还有其他毒素)在猪细小病毒毒力中的重要性 这些分离物。 这些重要的研究预计将：1)增加关于如何 CPE参与疾病，II)拓宽病理生理视角 肠道疾病的机制，III)允许将CPE作为一种定义的 质膜结构/功能关系的探测和iv)提供 一种理解产孢量相关毒力因子的模型 生物医学上重要的梭状芽胞杆菌属的调节。这些发现 应该对众多生物医学学科寻求 了解正常和疾病条件下的肠道生理和 肠道病原体如何引起胃肠道疾病。

Clostridium perfringens enterotoxin (CPE) is emerging as one of the most important bacterial virulence factors for gastrointestinal (G.I.) disease. There is compelling epidemiologic evidence for the involvement of CPE in one of the most common human food poisonings; recent studies also link CPE-positive C. perfringens to other serious human gastrointestinal illnesses and to Sudden Infant Death Syndrome. CPE has a unique action on mammalian membranes which is distinguishable from all other known toxins. Every step of CPE action involves close co-participation between CPE and mammalian membrane proteins. The long-term objective of this project is to understand the role of CPE (and CPE-positive isolates) in human disease; these studies may ultimately identify strategies to prevent or treat CPE-associated illnesses. To accomplish this objective, the following specific aims are proposed: 1) to test a recent hypothesis that a 50kDa membrane protein serves as a functional CPE receptor (the binding of CPE to the CPE receptor is essential for cytotoxicity) using "anti-receptor antibody" CPE binding inhibition studies and cloning of the CPE receptor, 2) to further clarify CPE action by a) determining the topologic orientation of CPE in membranes and b) dissecting individual events in CPE action using both biochemical and ultrastructural techniques, 3) to high-resolution map CPE functional regions (and eventually combine this information with CPE structural data) to identify how the CPE molecule participates in cytotoxicity and 4) to dissect the molecular pathogenesis of CPE-positive isolates by studying the importance of CPE (and possibly other toxins) in the virulence of these isolates. These important studies are expected to i) increase the knowledge of how CPE participates in disease, ii) broaden perspectives of pathophysiologic mechanisms of intestinal diseases, iii) allow use of CPE as a defined probe of plasma membrane structure/function relationships and iv) provide a model for understanding sporulation-associated virulence factor regulation in the biomedically important genus Clostridia. These findings should have significance for numerous biomedical disciplines seeking to understand intestinal physiology under normal and disease conditions and how enteric pathogens cause G.I. disease.