E. coli O157: H7 Vaccine Development

描述（由申请人提供）：我们的长期目标是开发人类疫苗，用于预防由大肠杆菌O157:H7引起的腹泻和/或溶血性尿毒综合征，以及由其他致病性大肠杆菌引起的腹泻。在目前提出的研究中，我们将筛选大肠杆菌O157:H7的基因组，以确定保护性抗原，这些抗原将成为人类疫苗的组成部分，这种方法可用于防止致病性大肠杆菌感染，而不影响共生菌群。中心假设是，鉴定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发作的疫苗的可行方法。近年来确定大肠杆菌O157:H7新型毒力因子的进展表明，它们可以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，这些蛋白质以前与毒力特性有关。因此，我们有理由提出，大肠杆菌O157: h7特异性基因可以成为疫苗组成部分的优秀候选者。我们提出的实验方法将侧重于两个具体目标：鉴定大肠杆菌O157:H7的O157特异性基因序列，并利用它们生成用于疫苗筛选优化的表达构建体文库；并利用大肠杆菌O157:H7感染小鼠模型确定O157特异性基因序列的保护能力，以确定亚单位候选疫苗的一个亚群。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，用于预防由大肠杆菌O157:H7引起的感染，并最终治疗由其他相关致病性大肠杆菌菌株引起的感染。大肠杆菌O157:H7是一种B类病原体，可能在食品和农业中用作生物威胁剂。

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. PUBLIC HEALTH RELEVANCE: Our objective is to screen the genome of E. coli O157:H7 (category B pathogen) to identify protective antigens that would become components of vaccine candidates in developing a human vaccine.