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TYPE 1 FIMBRIAE AND URINARY TRACT INFECTIONS

1 型菌毛和尿路感染

基本信息

批准号：
6624524
负责人：
DAVID L HASTY
金额：
$ 20.15万
依托单位：
UNIVERSITY OF TENNESSEE HEALTH SCI CTR
依托单位国家：
美国
项目类别：
财政年份：
1998
资助国家：
美国
起止时间：
1998-12-01 至 2004-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6624524
关键词：
Escherichia coli bacteria infection mechanism bacterial genetics bactericidal immunity cytokine enzyme linked immunosorbent assay gene expression histopathology host organism interaction immunocytochemistry laboratory mouse leukocyte activation /transformation pilus polymerase chain reaction urinary tract infection virulence

项目摘要

DESCRIPTION (Adapted from the Applicant's Abstract): Type I fimbriae are important for the urovirulence of E. coli, because they mediate adhesion, stimulate a mucosal immune response and mediate interactions with phagocytes. Experimental studies indicate the importance of type 1 fimbriae, but previous epidemiological studies found no correlation, perhaps because of the virtual ubiquity of the fim (type 1) gene cluster. Allelic variants of the gene for the FimH adhesin subunit that significantly alter the receptor-binding phenotype of E. coli have recently been discovered. Their distribution suggests that certain phenotypes offer a selective advantage in the urinary tract. This hypothesis is supported by preliminary animal studies. The effects of the expression of different fimH allelic variants on the ability of E. coli to colonize the mouse urinary tract will be studied. Isogenic E. coli strains will be inoculated into mouse bladders and infection studied by quantitative cultures and histopathology. We will identify the murine uroepithelial cell receptor(s) for E. coli expressing different fimH alleles. Preliminary studies lead us to focus on the asymmetrical unit membrane plaques (AUMs) of transitional epithelium and their constituent proteins, the uroplakins. In vitro and in vivo adhesion and adhesion inhibition assays (using uroplakin-specific antibodies) will be performed to confirm whether these molecules are the type 1 receptors. We will study the recruitment of leukocytes into the urinary tract mucosa of infected mice. The adhesion, ingestion and calling of E. coli by human and mouse peripheral blood PMN will be quantified and extracellular and intracellular release of oxygen metabolites will be measured. We will characterize the induction of cytokine production in urinary tract mucosa of mice infected with a recombinant E. coli strain exhibiting an M\H type 1 fimbrial phenotype typical of UTI isolates. When the basic responses have been characterized, we will determine whether qualitatively or quantitatively different responses are elicited by E. coli expressing different "fimH alleles. Production of inflammatory and regulatory cytokines will be measured by ELISAs and/or message will be measured by. RT-PCR. Cellular source(s) of cytokines will be determined by immunocytochemistry. The long-term goal of this research is to understand the role of type 1 fimbriae in the pathogenesis of UTIs to eventually enhance procedures for treatment or prevention.

描述(改编自申请者摘要)：I型菌毛为对大肠杆菌的尿毒力很重要，因为它们介导黏附，刺激粘膜免疫反应，调节相互作用吞噬细胞。实验研究表明类型的重要性 1菌毛，但以前的流行病学研究发现没有相关性，也许是因为fim(1型)基因几乎无处不在。集群。FimH粘附素亚基基因的等位变异显著改变大肠杆菌的受体结合表型最近才被发现。它们的分布表明，某些表型在尿路中提供了选择性优势。这这一假说得到了初步动物研究的支持。的影响不同fimH等位基因突变体对E. 大肠埃希氏菌在小鼠尿路中的定植将被研究。等位基因E. 将大肠埃希氏菌接种到小鼠膀胱内并感染通过定量培养和组织病理学研究。我们将确定小鼠尿上皮细胞受体(S)在大肠杆菌中的表达不同的FIMH等位基因。初步研究使我们将重点放在移行上皮不对称单位膜斑块它们的组成蛋白质，尿路蛋白。体外和体内黏附和黏附抑制试验(使用Uroplakin特异性抗体)，以确认这些分子是否是 1型受体。我们将研究白细胞在体内的募集情况感染小鼠的尿路粘膜。粘连、摄取和人和小鼠外周血中中性粒细胞对大肠杆菌的调用氧气的定量释放、细胞外和细胞内释放代谢物将被测量。我们将描述归纳的特征沙门氏菌感染小鼠尿路黏膜细胞因子的产生表现M\H1型菌毛表型的重组大肠杆菌典型的UTI分离株。当基本的反应已经被特征，我们将确定是定性还是定量大肠杆菌表达不同的fimH会引起不同的反应等位基因。炎症和调节性细胞因子的产生将是以ELISA衡量和/或消息将由衡量。RT-PCR法。蜂窝细胞因子的来源(S)将通过免疫细胞化学确定。这个这项研究的长期目标是了解类型1的作用菌毛在尿路感染发病机制中的作用最终加强程序用于治疗或预防。