Colonization and Pathogenicity Determinants of C. jejuni

描述（由申请人提供）：空肠弯曲杆菌是美国细菌性胃肠炎的最常见病因，也被NIAID生物防御研究议程指定为B类食品和水传播病原体。C的病例编号。空肠杆菌每年超过大肠杆菌、志贺氏菌，在某些年份甚至超过沙门氏菌。疾病控制中心估计，考虑到报告和未报告的病例，每年有多达200万人因弯曲杆菌病而患病。大量的人类病例是通过食用受污染和处理不当的鸡肉获得的。人类感染导致下肠道炎症，最终累及结肠和直肠。尽管该生物体作为人类病原体的重要性，但其毒力机制相对于其他病原体的毒力机制知之甚少。使用鸡感染模型在签名标记的诱变筛选中鉴定弯曲杆菌定殖决定簇。在该筛选中鉴定的基因中包括N-连接蛋白糖基化系统所需的那些基因，称为pgl基因。蛋白质糖基化在梭菌生物学和致病性相关行为中的作用。jejuni没有定义，但对C. jejuni的N-连接糖组进行了系统遗传分析。空肠已经揭示了在鸡模型中定殖所需的这些基因的子集。目的1将研究这些蛋白质中的三个，并确定它们在体内和体外C。以及蛋白质糖基化对它们的特异性影响。目的2将进一步研究鸡模型，其中有两个特定的子目的：第一个是分析口腔-胃接种后和整个胃肠道中的突变体、定植不良细菌的命运，第二个是检验以下假设：不以野生型效力定植鸡的突变体细菌诱导独特的先天免疫应答，导致其定植不良表型。目标3将开发和应用用于筛选小分子文库的检测方法，以抑制C。空肠致病性包括蛋白质糖基化和鞭毛组装。 该项目将揭示关于一种重要的人类病原体空肠弯曲菌的新知识。实验旨在确定糖基化蛋白在宿主细胞结合中的作用，以及在两种动物模型中的定植，包括鸡，一种天然的C。空肠是人类感染的主要来源。这项工作包括一个组成部分，将从基础科学的知识，在这个应用程序的开发新的试剂，用于研究和控制C。空肠感染

DESCRIPTION (provided by applicant): Campylobacter jejuni is the most prevalent cause of bacterial gastroenteritis in the United States, and is also designated a Category B food-and waterborne pathogen under the NIAID Biodefense Research Agenda. Case numbers for C. jejuni annually surpass those of Escherichia coli, Shigella and, in some years, even Salmonella species. The Centers for Disease Control have estimated that there are up to 2 million illnesses from campylobacteriosis each year, considering reported and unreported cases. A large number of human cases are acquired by eating contaminated and poorly prepared chicken. Infection of humans results in inflammation of the lower intestinal tract that ultimately involves the colon and rectum. Despite the importance of the organism as a human pathogen, its mechanisms of virulence are poorly understood relative to those of other pathogens. Campylobacter colonization determinants were identified in a signature-tagged mutagenesis screen using a chick infection model. Among the genes identified in this screen were those required for N-linked protein glycosylation system, called pgl genes. The role of protein glycosylation in the biology and pathogenicity-related behavior of C. jejuni is not defined, but systematic genetic analysis of the N-linked glycome of C. jejuni has revealed a subset of these genes that are required for colonization in a chick model. Aim 1 will investigate three of these proteins and determine their roles in both in vivo and in vitro models of C. jejuni pathogenicity as well as the specific effect of protein glycosylation on them. Aim 2 will investigate the chick model further with two specific sub-aims: the first is to analyze the fate of mutant, poorly colonizing bacteria after oro-gastric inoculation and throughout the gastrointestinal tract and the second is to test the hypothesis that mutant bacteria that do not colonize the chicken with wild type efficacy induce a unique innate immune response that contributes to their poor colonization phenotype. Aim 3 will develop and apply assays for screening a library of small molecules for those that inhibit key traits of C. jejuni pathogenicity including protein glycosylation and flagellar assembly. This project will uncover new knowledge about an important human pathogen, Campylobacter jejuni. Experiments are designed to define the role of glycosylated proteins in host-cell association and in two animal models of colonization, including chickens, a natural reservoir of C. jejuni and major source of human infection. The work includes a component that will translate the knowledge from the basic science in this application to development of new reagents for studying and controlling C. jejuni infections.