SHIGA-LIKE TOXIN--PATHOGENESIS IN DIARRHEA AND HUS

志贺氏菌病是一种世界性的疾病，在世界范围内引起显著的发病率和 发展中国家是腹泻病死亡的主要原因。这个 志贺氏菌引起最严重的疾病，痢疾，产生一种 抑制蛋白质合成的强效毒素分子。这种毒素由 一条A链和5条B链。B链的一个功能作用是 介导毒素与真核细胞表面的结合。毒素受体 是含有末端Gal-Alpha1-&Gt；4Gal二糖的糖脂。志贺 毒素现在被认为是一种毒素家族的原型 被称为类志贺。志贺和志贺类毒素相关 有许多临床表现，包括腹泻，痢疾， 出血性结肠炎和溶血性尿毒症综合征。 这一建议旨在研究生物多样性的基本结构-功能关系 毒素B链。一种与B细胞发生交叉反应的单抗 志贺链和志贺样毒素II将被表征。因为这些 两种毒素被认为在免疫上是不同的，而且由于这两种毒素 与一组相同的受体结合，将特别关注 关于该抗体是否针对结合区域。一个 单抗和带有Gal-Alpha1-&Gt；4Gal末端的糖蛋白 二糖，P1-糖蛋白，将被用作选择细菌的工具 产生结合结构域改变的B亚基的菌株。这个 对这些突变体的表征将提供对 参与受体识别的B链区域。此信息 将有助于未来安全有效的疫苗设计和 治疗干预方案的潜在设计。另外 一种物质的生化和遗传特征，它与 与志贺毒素抗体的反应将特别进行 强调揭示这种物质在发病机制中可能发挥的作用。 最后，其他革兰氏阴性菌产生的未鉴定的细胞毒素 生物体将被分析其志贺相似的特性。信息作为 其他致病菌是否产生志贺类毒素将有助于 我们对与毒素相关的疾病谱的理解。

Shigellosis is a world wide disease producing significant morbidity and in developing countries, a leading cause of diarrheal disease mortality. The Shigella species which causes the severest disease, dysenteriae, produces a potent toxin molecule which inhibits protein synthesis. The toxin consists of one A chain and 5 B chains. A functional role of the B chain is to mediate toxin binding to the eukaryotic cell surface. The toxin receptors are glycolipids containing terminal Gal-alpha1->4Gal disaccharide. Shiga toxin is now considered to be the prototype of a family of toxins which have been called Shiga-like. Shiga and Shiga-like toxins are associated with many clinical manifestations including diarrhea, dysentery, hemorrhagic colitis, and the hemolytic uremic syndrome. This proposal is designed to study basic structure-function relationship of the toxin B chain. A monoclonal antibody which cross-reacts with the B chain of Shiga and Shiga-like toxin II will be characterized. Since these two toxins are thought to be immunologically distinct and since the two bind to an identical set of receptors, particular attention will be focused on whether this antibody is directed against the binding domain. A monoclonal antibody and a glycoprotein with Gal-alpha1->4Gal terminal disaccharide, P1-glycoprotein, will be used as tools to select bacterial strains which produce B subunits with binding domain alterations. The characterization of these mutants will provide an understanding of the regions of the B chain involved in receptor recognition. This information will be useful for the future design of safe and effective vaccines and for the potential design of therapeutic intervention regimens. Additionally the biochemical and genetic characterization of a material which cross- reacts with antibody against Shiga toxin will be undertaken with particular emphasis on revealing the role this material may play in pathogenesis. Finally, the uncharacterized cytotoxins produced by other Gram-negative organisms will be analyzed for their Shiga-like properties. Information as to whether other pathogenic bacteria produce Shiga-like toxins will aid in our understanding of the spectrum of disease associated with toxin.