INTERACTION OF LIPOPOLYSACCHARIDES WITH SERUM PROTEINS

内毒素脂多糖（LPS），由于其功能性 定位于革兰氏阴性菌的外膜上， 在细菌与宿主的相互作用中起关键作用 的防御合作. 其中最重要的一个互动是与 血清蛋白，特别是补体系统的蛋白。 LPS的结构决定因素已被认为是 在确定革兰氏阴性菌的敏感性或耐药性时至关重要 细菌对血清补体的溶解作用。 同样 重要的是潜在的病理生理效应介导 通过血清后细菌释放的内毒素LPS 细菌溶解，包括休克、低血压和播散性 血管内凝血 尽管有许多血清因子 据报道，解毒LPS的内毒素活动， 这些因素及其作用机制仍不明确。 本提案中概述的实验旨在 研究特定LPS多糖结构的影响 对LPS和补体之间的相互作用， 非补体血清蛋白。 在这些研究中， 大分子LPS内含有的特异性LPS决定簇 通过操纵LPS亚基，聚集体将发生变化 混合物. 将专门构建的LPS制剂 用于研究LPS结构的机制 调节经典或替代信号的激活 补体途径。 对于这些实验，纯化的 两种途径的补体成分将用于评估 直接调节补体成分的相互作用， 特定的LPS结构。 这些研究将增加 了解结构参数 成分C1和C3用于区分自我和非自我。 将广泛使用放射性碘标记的光活化LPS 用于研究对LPS具有亲和力的血清组分的衍生物 它可以结合LPS并改变其生物学活性。 蛋白 将通过LPS交联鉴定的正常人血清的 通过生物化学和免疫学分析表征。 在 此外，将测试这些蛋白质抑制 LPS介导的鲎变形细胞裂解物（LAL）的凝固。 LPS失活因子的鉴定可以允许 开发潜在有用的诊断协议， 内毒素血症的治疗。

Endotoxic lipopolysaccharides (LPS), by virtue of their functional localization on the outer membrane of gram negative bacteria, play a pivotal role in the interaction of the bacterium with host defenses. One of the most important of these interactions is with serum proteins, particularly those of the complement system. Structural determinants of LPS have been recognized to be critical in defining sensitivity or resistance of gram negative bacteria to the lytic effects of serum complement. Equally important are the potential pathophysiological effects mediated by endotoxic LPS released from the bacterium following serum bacteriolysis, which include shock, hypotension and disseminated intravascular coagulation. In spite of the numerous serum factors reported to detoxify the endotoxic activities of LPS both the factors and their mechanism of action remain ill defined. The experiments outlined in this proposal have been designed to investigate the influence specific LPS polysaccharide structures have upon the interactions between LPS and both complement and non-complement serum proteins. For these studies the levels of specific LPS determinants contained within macromolecular LPS aggregates will be varied by manipulating LPS subunit composition. Specifically constructed LPS preparations will be used to investigate the mechanisms by which LPS structures regulate the activation of both the classical or alternative pathways of complement. For these experiments, purified complement components of both pathways will be used to assess directly the modulation of complement component interactions by specific LPS structures. These studies will increase the understanding of the structural parameters which allow components C1 and C3 to descriminate between self and non-self. Extensive use will be made of a radioiodinated photoactivable LPS derivitive to study serum components with an affinity for LPS which could bind LPS and alter its biological activities. Proteins of normal human serum identified by LPS crosslinking will be characterized by biochemical and immunological analysis. In addition, these proteins will be tested for their capacity to inhibit LPS mediated coagulation of Limulus ameobocyte lysates (LAL). Identification of LPS inactivating factors could allow for the development of potentially useful protocols for the diagnosis and treatment of endotoxemia.