E. coli O157: H7 Vaccine Development

描述(申请人提供)：我们的长期目标是开发预防由O157：H7大肠杆菌引起的腹泻和/或HUS以及由其他致病性大肠杆菌引起的腹泻的人类疫苗。在目前提出的研究中，我们将筛选E.ColiO157：H7的基因组，以确定将成为人类疫苗组成部分的保护性抗原，这种方法可以在不影响共生菌群的情况下用于预防致病性大肠杆菌感染。中心假设是，识别O157：H7特有的保护性抗原是开发预防腹泻和溶血性尿毒症综合征的疫苗的可行方法。近年来，鉴定大肠杆菌O157：H7新毒力因子的进展表明，它们可能成为候选疫苗的有用成分。特别值得注意的是那些在细菌膜上表达或分泌到细胞外环境的蛋白质，这些蛋白质以前一直与毒力特征有关。因此，提出大肠杆菌O157：H7的特异性基因可以成为疫苗的优秀候选成分是合理的。我们提出的实验方法将集中在两个特定的目标上：鉴定大肠杆菌O157：H7的O157特异性基因序列，并使用它们来生成优化用于疫苗筛选的表达构建体的文库；以及使用大肠杆菌O157：H7感染的小鼠模型来确定O157特异性基因序列的保护能力，以确定候选亚单位疫苗的子集。我们的建议意义重大，因为它有望提供开发最佳疫苗所需的基本知识，该疫苗将用于预防由O157：H7大肠杆菌引起的感染，O157：H7是一种B类病原体，可能在食品和农业中用作生物治疗剂，最终用于治疗由其他相关致病大肠杆菌菌株引起的感染。

DESCRIPTION (provided by applicant): Our long-term goal is to develop human vaccines for the prevention of diarrhea and/or HUS caused by E. coli O157:H7 and diarrhea by other pathogenic E. coli. In the currently proposed studies, we will screen the genome of E. coli O157:H7 to identify protective antigens that would become components of a human vaccine, and such approach can be used to protect against pathogenic E. coli infections without affecting commensal flora. The central hypothesis is that identification of protective antigens unique to O157:H7 is a viable approach for development of a vaccine for prevention of diarrhea and Hemolytic Uremic Syndrome episodes. Progress in recent years identifying E. coli O157:H7 novel virulence factors suggest that they can become useful components of a vaccine candidate. Of particular note are those proteins expressed on the bacterial membranes or secreted to the extracellular milieu, which have been previously associated with virulence traits. Therefore, it is plausible to propose that E. coli O157:H7-specific genes can become excellent candidates as components of vaccines. Our proposed experimental approach will focus on two specific aims: Identify the O157-specific gene sequences of E. coli O157:H7 and use them to generate a library of expression constructs optimized for vaccine screening; and determine the protective capacity of O157-specific gene sequence using a murine model of E. coli O157:H7 infection, to identify a subset of subunit vaccine candidates. Our proposal is significant because it is expected to provide the basic knowledge needed to develop an optimal vaccine that will be used to prevent infections caused by E. coli O157:H7, a category B pathogen for its potential use as biothreat agents in food and agriculture, and eventually to treat infections caused by other related pathogenic E. coli strains.