The Psa fimbriae of Yersinia pestis, an adhesin with protective immunogenic prope

描述（由申请人提供）：鼠疫耶尔森氏菌是最著名的腺鼠疫病原体，腺鼠疫是一种通过受感染跳蚤叮咬传播的疾病。然而，如果吸入，这种病原体也会产生一种称为肺鼠疫的严重原发性肺炎，这种肺炎既具有传染性又具有高度致命性。尽管一种实验性疫苗由Y.尽管鼠疫F1和LcrV蛋白在小鼠模型中得到了令人鼓舞的结果，但在灵长类动物中针对肺鼠疫的有效疫苗仍然是难以捉摸的。此外，F1缺陷株的Y.鼠疫保留了引起肺鼠疫的能力，这使得由于F1/LcrV接种个体中F1表达的自发或工程化丧失而可能破坏保护。包括我们自己在内的几个小组的实验数据表明，体内细胞外细菌上表达pH 6抗原（Psa菌毛）。我们最近观察到，接种Psa可以显着预防减毒Y杆菌。鼠疫菌株在小鼠肺部感染实验中的应用。本研究的第一个目的是通过用完全强毒株KIM1001和CO92攻击小鼠来进一步验证Psa的保护特性。将在平行实验中研究用于减毒pgm菌株KIM 5的铁处理小鼠模型的价值。将建立抗体和T细胞介导的保护的体外相关性。正如我们已经证明的那样，Psa蛋白抗原诱导强烈的体液反应，将评估抗体从接种疫苗的小鼠转移到幼稚小鼠的被动保护作用。将通过免疫和T细胞转移实验在B细胞缺陷小鼠中评估T细胞介导的保护的参与。我们的第二个目标是表征Psa在鼠疫致病性中的作用。我们已经证明，Psa菌毛是介导Y。鼠疫杆菌通过与磷脂酰胆碱的胆碱部分的高亲合力和与糖脂的21-连接的半乳糖残基的较低亲合力相互作用而与人呼吸道上皮细胞结合。正如我们（和其他人）已经证明的那样，Psa加速了Y。鼠疫菌在受感染宿主中的传播，我们将评估是否PSA介导的粘附有助于这种反应。将对不能与胆碱或/和21-连接的半乳糖基结合的定点Psa流苏状突变体进行工程改造，并在小鼠中研究其传播特性。所得结果将指导能够阻断Psa介导的细菌粘附的聚合物抑制剂的设计。鉴定延迟细菌体内传播的抑制剂将支持粘附抑制剂作为抗毒性治疗剂的未来发展。我们的第一个目标是确定Psa是否是一种有价值的免疫原，可以添加到目前的实验性F1-LcrV疫苗中，以提供更广泛的预防鼠疫，特别是肺炎形式。我们的第二个目标是确定PSA介导的粘附是否有助于毒力，以及设计用于阻断PSA介导的粘附的治疗方法的开发是否可以延迟疾病进展，从而提高抗生素治疗的成功率。公共卫生相关性：这项提案的第一个目标是确定鼠疫耶尔森氏菌表面结构，Psa菌毛，作为预防鼠疫的保护性免疫原的用途。第二个目标是表征Psa抑制剂的使用，Psa通过支持宿主的细菌定殖和疾病进展而充当毒力因子。这些研究结果将为未来开发支持传统抗生素治疗的疫苗和药物提供有用的基础。

DESCRIPTION (provided by applicant): Yersinia pestis is best known as the causative agent of bubonic plague, a disease transmitted by the bite of infected fleas. However, if inhaled, this pathogen also produces a severe primary pneumonia known as pneumonic plague, which is both contagious and highly lethal. Although an experimental vaccine that consists of Y. pestis F1 and LcrV proteins has given encouraging results in murine models, an efficient vaccine against pneumonic plague in primates remains elusive. Moreover, F1-deficient strains of Y. pestis retain the ability to cause pneumonic plague, allowing for the potential breakdown of protection due to spontaneous or engineered loss of F1 expression in F1/LcrV vaccinated individuals. Experimental data from several groups, including our own, indicates that the pH 6 antigen (Psa fimbriae) is expressed on extracellular bacteria in vivo. We recently observed that vaccination with Psa affords significant protection against an attenuated Y. pestis strain in pulmonary infection experiments in mice. The first aim of this study is to further verify the protective properties of Psa by challenging mice with the fully virulent strains KIM1001 and CO92. The value of an iron-treated mouse model for use with the attenuated pgm strain KIM5 will be investigated in parallel experiments. In vitro correlates of antibody- and T cell-mediated protection will be established. As we have shown that the Psa protein antigen induces a strong humoral response, passive protection by antibody transfer from vaccinated to naive mice will be evaluated. The involvement of T cell-mediated protection will be evaluated in B-cell deficient mice by immunization and T cell transfer experiments. Our second aim is to characterize the role of Psa in plague pathogenicity. We have shown that the Psa fimbriae are multimeric adhesins that mediate Y. pestis binding to human respiratory tract epithelial cells by interacting with high avidity to choline moieties of phosphatidylcholine, and with lower avidity to 21-linked galactosyl residues of glycolipids. As we (and others) have demonstrated that Psa accelerates Y. pestis dissemination in infected hosts, we shall evaluate whether Psa-mediated adhesion contributes to this response. Site-directed Psa fimbriated mutants unable to bind to choline or/and 21-linked galactosyl will be engineered and their disseminating properties will be investigated in mice. The results obtained will guide the design of polymeric inhibitors capable of blocking Psa-mediated bacterial adhesion. Identifying inhibitors that delay bacterial dissemination in vivo will support future development of adhesion inhibitors as anti-virulence therapeutics. The goal of our first aim is to determine if Psa would be a valuable immunogen to add to the current experimental F1-LcrV vaccine to offer a broader protection against plague and particularly the pneumonic form. The goal of our second aim is to determine if Psa-mediated adhesion contributes to virulence and if development of therapeutics designed to block Psa-mediated adhesion could delay disease progression, thereby improving the success of antibiotic treatments. PUBLIC HEALTH RELEVANCE: This proposal's first goal is to determine the use of a Yersinia pestis surface structure, the Psa fimbriae, as a protective immunogen against plague. A second goal is to characterize the use of inhibitors of Psa, Psa acting as a virulence factor by supporting bacterial colonization of the host and disease progression. The result of these studies will provide a useful basis for future development of vaccines and drugs that support traditional antibiotic therapy.