BORDETELLA PERTUSSIS TRACHEAL CYTOTOXIN

描述（改编自申请人的摘要）：各种 百日咳杆菌产生的毒素和毒力相关因子， 只有一种被证明可以复制特定的呼吸道 百日咳综合征的道细胞病理学 该分子 气管细胞毒素（TCT），一种921道尔顿的肽聚糖片段 在正常生长期被百日咳杆菌感染 近3年 由NIH拨款的资金，大部分的研究工作， 以理解TCT结构-功能关系为中心， 确定TCT靶细胞，阐明TCT作用机制。 此更新应用程序侧重于实验，以描述 进一步的TCT毒性途径，靶细胞特异性， TCT生产的分子基础。 要求5年， 探讨以下具体目标：一。更准确地定义角色 白细胞介素-1（IL-1）和一氧化氮（NO）在 TCT行动。 实验将评估IL-1是否真的是一种 TCT毒性途径中的重要步骤，并将定义 对TCT有反应的特定呼吸道上皮细胞（以及 百日咳杆菌感染）通过合成IL-1和/或NO ; 类似的研究将被设计来检查分子基础， 对TCT的物种特异性反应。二.比较TCT的毒性， 嗜中性粒细胞的已知生物化学和生物学TCT的呼吸 上皮效应TCT对中性粒细胞的有效作用将是 在与我们以前的工作平行的实验中进行了检查， 呼吸道上皮细胞：结构-活性关系，证据 对于与表面受体的结合，IL-1和 NO，以及与内毒素协同作用的可能性。三.识别 百日咳博德特氏菌释放TCT遗传学和生物学基础 这些实验将检验百日咳杆菌 TCT的释放主要是由于膜的缺陷或缺失 转运蛋白 AmpG，对肽聚糖至关重要 回收利用。 此外，一种新的突变体筛选将用于识别 可能参与TCT产生的其他基因。

DESCRIPTION (Adapted from applicant's abstract): Of the various toxins and virulence-related factors produced by Bordetella pertussis, only one has been demonstrated to reproduce the specific respiratory tract cytopathology of the pertussis syndrome. That molecule is tracheal cytotoxin (TCT),a 921 dalton peptidoglycan fragment released by Bordetella pertussis during normal growth. During the past 3 years of funding by this NIH grant, most of the research effort has centered on understanding TCT structure-function relationships, defining TCT target cells, and elucidating TCT mechanism of action. This renewal application is focused on experiments to describe further the TCT toxicity pathway, target cell specificity, and the molecular basis for TCT production. Five years are requested to explore the following specific aims: I. Define more precisely the role of interleukin-1 (IL-1) and nitric oxide (NO ) in the mechanism of TCT action. Experiments will evaluate whether IL-1 is indeed an essential step in the TCT toxicity pathway and will define the specific respiratory epithelial cells that respond to TCT (and Bordetella pertussis infection) by synthesizing IL-1 and/or NO ; similar studies will be designed to examine the molecular basis for species-specific responsiveness to TCT. II. Compare TCT's toxicity for neutrophils to the known biochemistry and biology of TCT's respiratory epithelial effects. The potent effects of TCT on neutrophils will be examined in experiments that parallel our previous work with respiratory epithelial cells: structure-activity relationships, evidence for binding to a surface receptor, the potential involvement of IL-1 and NO , and the possibility of synergy with endotoxin. III. Identify the genetic and biological basis of TCT release by Bordetella pertussis. These experiments will test the hypothesis that Bordetella pertussis release of TCT is largely due to a defective or missing membrane transport protein. AmpG, that is critical for peptidoglycan recycling. In addition, a novel mutant screen will be used to identify other gene(s) that may be involved in production of TCT.