Shigella dysenteriae vaccine construction

描述(由申请人提供)：1型志贺氏菌是最可怕的B类优先药物之一，因为它在低剂量下具有高传染性，严重的疾病后遗症，以及在幼稚人口中引起爆炸性流行病的能力。目前还没有预防性疫苗或特定疗法来预防这种病原体引起的疾病，而且对大多数临床分离株的治疗选择有限，因为这些菌株对抗生素的耐药性越来越强。1型痢疾杆菌很容易通过受污染的食物或水传播，故意的污染行为可能会导致对这种微生物没有免疫力的人群发生广泛的严重疾病和死亡。最近对减毒志贺氏菌进行的临床试验加强了活志贺氏菌候选疫苗的安全性和有效性，并证实了guaba、set和sen基因突变的减弱能力。这些数据为合理设计一系列活的、减毒的痢疾杆菌疫苗株提供了一种策略，该疫苗株除了消除志贺毒素的活性外，还基于这些突变的组合。此外，通过在这些减毒菌株中插入一个结构性启动子来驱动志贺毒素B亚单位的表达，志贺毒素可以激发中和免疫反应，不仅对志贺氏菌群具有保护作用，而且对其他产生志贺毒素的病原体也具有保护作用。利用我们收集的已知临床结果的福氏志贺氏菌疫苗毒株，我们建议修改动物和体外试验，以提高在临床前水平区分不同毒株的敏感性。改进的分析将允许对后续临床表现的更大预测能力，从而加快最有希望的候选菌株进入临床试验和生产的进程。然后，减毒活菌株可用于表达来自其他优先病原体的保护性抗原或表位。我们将设计稳定的、染色体整合的、通过与ClyA融合的分泌形式的炭疽杆菌PA的表达系统。相关性：这些研究将导致一系列减毒志贺氏菌活疫苗候选进入临床试验，并用于开发多价口服疫苗，以预防多种优先媒介疾病，帮助保护公民免受潜在的生物伤害。

DESCRIPTION (provided by applicant): Shigella dysenteriae Type 1 is one of the most fearsome of the Category B Priority agents owing to its high infectivity at low doses, severe disease sequelae, and ability to cause explosive epidemics in naive populations. No prophylactic vaccine or specific therapy exists for prevention of disease caused by this pathogen and therapeutic options are limited against the majority of clinical isolates which are increasingly multiply antibiotic resistant. S. dysenteriae Type 1 is easily spread by tainted food or water and an intentional act of contamination could lead to widespread serious disease and death in a population with no immunity to this organism. Recent clinical trials with attenuated strains of Shigella flexneri have reinforced the safety and efficacy, of live Shigella vaccine candidates and confirmed the attenuating capacity of mutations in the guaBA, set, and sen genes. These data provide a strategy for the rational design of a series of live, attenuated S. dysenteriae vaccine strains based on a combination of these mutations in addition to elimination of shiga toxin activity. In addition, by inserting a constitutive promoter driving expression of the shiga toxin B subunit in these attenuated strains, shiga toxin neutralizing immune responses could be elicited and provide protection not only against S. dysenterae but also against other shiga toxin-producing pathogens. Using our collection of S. flexneri vaccine strains with known clinical outcomes we propose to modify animal and in vitro assays to increase the sensitivity for distinguishing differences between strains at the preclinical level. Refined assays will allow greater predictive power of subsequent clinical performance resulting in accelerated advancement of the most promising candidate strain or strains to clinical trials and production. The live attenuated strains can then be used to express protective antigens or epitopes from other priority pathogens. We will design systems for expression of PA from B. anthracis from stabilized plasmid constructs, chromosomally integrated and in secreted form by fusion to ClyA. Relevance: These studies will result in a series of live attenuated Shigella dysenteriae vaccine candidates for advancement to clinical trials and for use in the development of a multivalent, oral vaccine to protect against multiple priority agent diseases which will help protect citizens from potential biothreats.