Spotted Fever Rickettesial Antigens

描述(申请人提供)：本项目的长期目标是阐明斑点热群立克次体的保护性免疫机制。通过静脉接种康氏立克次体建立的保护性免疫机制的强大框架已经确定了我们的知识中的一个重要缺口，即最初的感染事件。这一竞争性的更新应用程序提出通过以下实验缩小这一差距：皮内接种、立克次体与树突状细胞的相互作用、引流淋巴结中的T淋巴细胞启动、树突状细胞与自然杀伤细胞的相互作用以及血圆线虫唾液的免疫调节作用。初步结果表明，孔氏杆菌能激活树突状细胞，从而影响感染的结局。其具体目的是：1)检测立克次体体外和体内对立克次体感染具有遗传抗性和易感的近交系小鼠树突状细胞(DC)的反应差异，以及立克次体接种物中壁虱唾液的存在对立克次体-DC相互作用的影响；2)确定康氏立克次体激活DC在体内斑点热立克次体发病机制中的作用，包括对先天免疫和获得性免疫的影响，以及立克次体接种剂中的壁虱唾液对抗立克次体免疫反应的影响。 实验设计利用了成熟的小鼠模型，包括一个具有完全先天抵抗力的小鼠模型，一个由科诺里杆菌引起的剂量依赖死亡模型，以及一个使用能够使用基因敲除方法导致C57BL/6小鼠剂量依赖死亡的澳大利亚R。在体外研究、流式细胞术、实时定量聚合酶链式反应检测立克次体负荷、免疫组织化学、细胞因子分析、ELISPOT分析、CTL分析和其他免疫学方法将被用于严格设计的实验，以确定有效的抗立克次体免疫生成。

DESCRIPTION (provided by applicant): The long-term goal of this project is the elucidation of the mechanisms of protective immunity against spotted fever group rickettsiae. A strong framework of knowledge of the mechanisms of protective immunity that clear disseminated endothelial infection established by intravenous inoculation of Rickettsia conorii into susceptible C3H mice has identified an important gap in our knowledge, namely of the initial infection events. This competing renewal application proposes to close that gap by experiments focused on intradermal inoculation, rickettsial interactions with dendritic cells, T lymphocyte priming in the draining lymph nodes, dendritic cell-NK cell cross talk, and immunomodulatory effects of Rhipicephalus sanguineus tick saliva. Preliminary results indicate that R. conorii activates dendritic cells, which influence the outcome of infection. The specific aims are 1) Determine the differences between the responses of dendritic cells of inbred mice genetically resistant or susceptible to Rickettsia conorii infection when the dendritic cells (DCs) are activated by the rickettsiae in vitro and in vivo and the effects of the presence of tick saliva in the rickettsial inoculum on the rickettsia-DC interaction and 2) Determine the role of activation of DCs by R. conorii on the pathogenesis of spotted fever rickettsiosis in vivo, including the effects on innate and adaptive immunity, and the effects of tick saliva in the rickettsial inoculum on the anti-rickettsial immune response. The experimental design takes advantage of well-established mouse models including one with complete innate resistance, one with dose-dependent mortality caused by R. conorii, and one employing R. australis that causes dose-dependent mortality in C57BL/6 mice enabling use of gene knockout approaches. In vitro studies, flow cytometry, real time PCR measurement of rickettsial load, immunohistochemistry, cytokine assays, ELISPOT assays, CTL assays, and other immunological approaches will be utilized in critically designed experiments to determine the effective generation of anti-rickettsial immunity.