Host Response

腹泻病是5岁以下儿童的主要杀手。这些感染代表了微生物和宿主之间的平衡。宿主对肠道感染的反应包括在肠上皮和粘膜/全身免疫系统中看到的反应。该项目将使用小鼠肠道组织和人类临床标本来检查这两种类型的反应。特异性目的1将描述安装在Ussing chamber和microsnapwell中的小鼠上皮组织对志贺氏菌和致病性大肠杆菌（EPEC）感染的反应，特别强调肠道屏障功能、短路电流和上皮细胞因子的产生。将测试几种在特定毒力因子中有缺陷的等基因突变体，以确定这些因素对所见反应的贡献。与使用野生型小鼠和各种细菌突变体的Aim 1不同，特异性Aim 2将使用野生型细菌和各种突变小鼠菌株来确定特异性模式识别受体（PRRs）在肠黏膜对志贺氏菌和EPEC的反应中的作用。将从野生型小鼠中分离出肠道组织，敲除MyD88、TLR4、TLR5、Nodi、Nod2、PAR2或肥大细胞缺陷，并在体外暴露于志贺氏菌和EPEC。比较不同小鼠系的肠黏膜功能和免疫反应将表征这些PRRs在EPEC和志贺氏菌感染中的作用。特异性目标3将检查与志贺菌和EPEC感染在流行国家儿童中相关的Gl道适应性免疫和免疫标记物。GEMS研究中将分析记录在案的志贺氏菌和EPEC感染儿童的粪便标本，以确定病原体特异性适应性反应，包括志贺氏菌和EPEC抗原特异性sIgA、IgA和IgG。还将分析粪便细胞因子和炎症分子，并寻求与临床结果的相关性。

Diarrheal diseases are a major killer of children under the age of 5. These infections infections represent a balance between the microbe and the host. Host responses to enteric infections include those seen in the intestinal epithelium and in the mucosal/systemic immune system. This project will examine both types of responses using mouse intestinal tissue and human clinical specimens. Specific Aim 1 will characterize the response of mouse epithelial tissue mounted in Ussing chambers and microsnapwells to infection with Shigella and enteropathogenic E. coli (EPEC) with particular emphasis on intestinal barrier function, short circuit current, and epithelial cytokine production. Several isogenic mutants defective in specific virulence factors will be tested to determine the contribution of these factors to the responses seen. In contrast to Aim 1, which will employ wild type mice and various bacterial mutants, Specific Aim 2 will employ wild type bacteria and various mutant mouse strains to establish the role of specific pattern recognition receptors (PRRs) in the intestinal mucosal response to Shigella and EPEC. Intestinal tissue will be isolated from wild type and knock out mice deficient in MyD88, TLR4, TLR5, Nodi, Nod2, PAR2 , or mast cells and exposed ex vivo to Shigella and EPEC. Comparison of the intestinal mucosal function and immune responses in the different mouse lines will characterize the role of these PRRs in infections due to EPEC and Shigella. Specific Aim 3 will examine adaptive immunity and immunological markers in the Gl tract that are associated with Shigella and EPEC infection in children from endemic countries. Stool specimens from children with documented Shigella and EPEC infections in the GEMS study will be analyzed for pathogen specific adaptive responses including sIgA, IgA, and IgG specific for Shigella and EPEC antigens. Fecal cytokines and inflammatory molecules will also be analyzed and correlations sought with clinical outcomes.