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肠道上皮和粘膜/系统免疫系统中的反应。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。具体目标1将描述安装在Ussing小室和微Snapwell中的小鼠上皮组织对志贺氏菌和产肠病原性大肠杆菌(EPEC)感染的反应，特别强调肠屏障功能、短路电流和上皮细胞因子的产生。将测试几个在特定毒力因子上存在缺陷的等基因突变体，以确定这些因子对所看到的反应的贡献。与使用野生型小鼠和各种细菌突变体的目标1不同，特定目标2将使用野生型细菌和各种突变小鼠品系来建立特定模式识别受体(PRRs)在肠黏膜对志贺氏菌和EPEC的反应中的作用。肠道组织将从野生型中分离出来，并敲除MyD88、TLR4、TLR5、NODI、NOD2、PAR2或肥大细胞缺陷的小鼠，并在体外暴露于志贺氏菌和EPEC。通过比较不同品系小鼠的肠道粘膜功能和免疫反应，将确定这些PRRs在EPEC和志贺氏菌感染中的作用。具体目标3将检查与流行国家儿童中志贺氏菌和EPEC感染有关的Gl区的获得性免疫和免疫标志物。GEMS研究中记录的志贺氏菌和EPEC感染儿童的粪便样本将被分析病原体特定的适应性反应，包括针对志贺氏菌和EPEC抗原的SIgA、IgA和Ig G。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.