ENTEROTOXIN FACTORS ELABORATED BY SHIGELLA FLEXNERI

描述（改编自申请人摘要）：长期目标 拟议的项目是描述新的肠毒性决定因素 可能参与福氏志贺菌腹泻的发病机制。 的 减毒鼠伤寒沙门迄今为止，测试的福氏疫苗候选物显示出各种各样的 反应原性的程度，特别是水样腹泻。 PI研究 导致了由S.福氏 这是以前没有描述过的。 这些毒素可能是 志贺氏菌疫苗试验期间观察到的残留腹泻。 的PI 建议进一步研究这些发现，在一个基本的混合， 应用研究，这将产生对发病机制的基本见解 色葡萄弗氏痢疾。 这些发现也将提供关键的 这些信息可以应用于设计改进的减毒疫苗。 目的1：分离纯化一种新的肠毒因子. 在动物体内和体外诱导分泌的弗氏2a 模型 PI已经部分纯化了这种毒素，称为ShET 1， 志贺氏菌肠毒素1，现在打算进一步纯化该部分， 产生特异性单克隆抗体。 AIM 2. 研究ShET 1基因的遗传调控，构建ShET 1突变体， set 1基因 PI已经鉴定、克隆并测序了 编码该因子的染色体区域。 他现在将描述这些 基因及其调控机制。 目的3.探讨ShET 1在志贺菌病发病机制中的作用， 研究其作用机制。 PI将进行肠道灌注 在人类志愿者中的研究，并使用动物模型，将确定ShET 1 与肠上皮细胞受体的相互作用及其对跨上皮水的影响 和电解质转运，以及其细胞内介质 肠毒性作用 AIM 4. 为了确定ShET 1和肠侵袭性大肠杆菌是否 肠毒素（EIET/ShET 2），最近由该研究所描述的第二种肠毒素， 组，共享任何功能相似性。

DESCRIPTION (Adapted from applicant's abstract): The long term objective of the proposed project is to characterize new enterotoxic determinants potentially involved in the pathogenesis of Shigella flexneri diarrhea. The attenuated S. flexneri vaccine candidates tested so far have shown various degrees of reactogenicity, particularly watery diarrhea. Studies of the PI have resulted in the discovery of enterotoxins elaborated by S. flexneri that have not previously been described. These toxins may be responsible for the residual diarrhea observed during Shigella vaccine trials. The PI proposes to investigate these findings further in a blend of basic and applied studies which will yield fundamental insights into the pathogenesis of S. flexneri diarrhea. These findings will also provide crucial information that can be applied to engineer improved attenuated vaccines. Specific aims are: AIM 1: To purify a new enterotoxic factor of S. flexneri 2a which induces secretion both in vivo and in vitro in animal models. The PI has already partially purified this toxin, termed ShET1 for Shigella enterotoxin 1, and now intends to purify this moiety further and to raise specific monoclonal antibodies to it. AIM 2. To study the genetic regulation of ShET1 and to construct mutants of the set1 genes. The PI has identified, cloned, and sequenced the chromosomal region encoding this factor. He will now characterize these genes and their mechanisms of regulation. AIM 3.To establish the role of ShET1 in the pathogenesis of shigellosis and to study its mechanism of action. The PI will perform intestinal perfusion studies in human volunteers and, using an animal model, will determine ShET1 interaction with enterocyte receptors, its effects on transepithelial water and electrolyte transport, and the intracellular mediator(s) of its enterotoxic effect. AIM 4. To determine whether ShET1 and enteroinvasive Escherichia coli enterotoxin (EIET/ShET2), a second enterotoxin recently described by this group, share any functional similarities.