Evaluation of Ail as a protective immunogen for plague

描述（由申请人提供）：Ail蛋白家族已显示在几种致病性耶尔森氏菌属物种中介导细胞粘附和对人血清的抗性。我们最近已经表明，Ail对于将来自鼠疫耶尔森氏菌的细胞毒性Yop蛋白递送至吞噬和非吞噬人类细胞是重要的。体外Yop递送的这种缺陷反映在Yop的α 1突变体的LD 50增加> 3，000倍。鼠疫KIM5通过静脉途径感染。沿着α 1突变体的毒力降低，我们还观察到基于组织学的感染的脾和肝组织内炎症增加，并且在感染后三天这些组织中细菌负荷大大降低.如果抑制Yop递送，导致抗炎Yop递送不足，则这是预期结果。 由于Ail在鼠疫发病机制中的主要作用，我们建议使用最近纯化的Ail蛋白来确定Ail免疫保护未接种小鼠免受野生型（完全毒力）Y.鼠疫感染通过皮下（腺鼠疫）或鼻内（肺鼠疫）传播。用Y.鼠疫或非免疫抑制衍生物VlO是鼠疫疫苗接种领域的标准，我们还将表征Ail与VlO一起提供的组合保护。 Y.鼠疫是鼠疫的病原体，是一种迅速致命的疾病和潜在的生物恐怖主义威胁。目前在美国没有获得许可的鼠疫疫苗，最近的报告表明逃逸突变体可能会破坏利用F1胶囊作为免疫原的疫苗的效力。因此，鉴定和开发用于未来鼠疫疫苗制剂的额外保护性抗原至关重要。鉴于Y.由于鼠疫Ail在Yop中的递送和毒力，它是用于使用动物模型的免疫试验的极好的候选抗原。这项建议的具体目的是：1.评估Ail免疫预防小鼠鼠疫的效果2.评估Ail + V10（V抗原的衍生物）对小鼠中累积鼠疫保护的功效 公共卫生相关性：该项目将测试一种新的疫苗抗原Ail的有效性，其保护小鼠免受鼠疫的能力。如果Ail被证明可以保护动物免受疾病的侵害，它可以被纳入未来的疫苗配方中，以预防人类的鼠疫。鼠疫是一种快速致命的传染病和潜在的生物恐怖主义威胁，目前在美国没有获得许可的疫苗。

DESCRIPTION (provided by applicant): The Ail family of proteins has been shown to mediate cell adhesion and resistance to human serum in several pathogenic Yersinia species. We have recently shown that Ail is important for delivery of cytotoxic Yop proteins from Yersinia pestis to phagocytic and non-phagocytic human cells. This defect in Yop delivery in vitro is reflected in the >3,000-fold increase in LD50 of a (ail mutant of Y. pestis KIM5 by the intravenous route of infection. Along with the decreased virulence of the (ail mutant, we also observed increased inflammation within infected spleen and liver tissues based on histology and greatly decreased bacterial loads in these tissues three days post- infection. This is the expected result if Yop delivery is inhibited, leading to lack of delivery of anti-inflammatory Yops. Due to the major role of Ail in plague pathogenesis, we propose to use a recently purified Ail protein to determine the ability of Ail immunization to protect naive mice from wild-type (fully virulent) Y. pestis infection delivered subcutaneously (bubonic plague) or intranasally (pneumonic plague). Given that experimental immunization with V antigen of Y. pestis or the non-immunosuppressive derivative V10 are standards in the field for plague vaccination, we will also characterize the combined protection provided by Ail together with V10. Y. pestis is the etiological agent of plague, a rapidly fatal disease and potential bioterrorism threat. There is currently no licensed plague vaccine in the U.S. and recent reports indicate escape mutants may undermine the efficacy of vaccines utilizing the F1 capsule as an immunogen. Thus, identification and development of additional protective antigens for future plague vaccine formulations are essential. Given the critical role for Y. pestis Ail in Yop delivery and virulence, it is an excellent candidate antigen for immunization trials using an animal model. The specific Aims of this proposal are: 1. Assess the efficacy of Ail immunization for preventing plague in mice 2. Assess the efficacy of Ail + V10 (a derivative of V antigen) for cumulative plague protection in mice PUBLIC HEALTH RELEVANCE: This project will test the efficacy of a new vaccine antigen, Ail, for its ability to protect mice from plague. If Ail proves to protect animals from disease, it could be incorporated into future vaccine formulations to prevent plague in humans. Plague is a rapidly-fatal infectious disease and potential bioterrorism threat with no currently licensed vaccine in the U.S.