Identification of T Cell Antigen For Q Fever Vaccination

描述(申请人提供)：伯氏柯克斯体是Q热的病原体，是一种B类生物恐怖分子，对人和牲畜都有很高的感染性。人类感染主要是由气溶胶传播引起的，伯氏梭菌可以抵抗干燥，并在受污染的土壤中保持几年的传染性。容易通过气雾剂传播、环境持久性和高传染性(ID50=1)使伯氏梭菌对军事人员和平民构成严重威胁。这种毒剂已经在各种生物战计划下武器化和大规模生产。因此，迫切需要开发一种有效的疫苗，并可在推定或确认暴发后安全地用于靶向或大规模疫苗接种。目前，还没有符合这些标准的疫苗--我们提出了一种策略，以确定符合这些标准的已定义的伯内蒂弧菌免疫原。 我们建议使用一种新的蛋白质组学方法结合筛选所需的细胞介导的反应来鉴定和测试已定义的布氏梭菌免疫原，这种方法利用了最近完成的九英里菌株基因组序列。伯氏杆菌的细胞内杀伤是通过干扰素-γ介导的，并与强烈刺激一氧化氮的产生有关。因此，疫苗诱导的免疫依赖于CD4+T淋巴细胞的启动和扩增，这些T淋巴细胞能够识别感染的巨噬细胞，通过递呈C-Burnetti抗原和分泌高水平的干扰素-γ来识别感染的巨噬细胞。在这个项目中，我们将测试以下假设：i)通过刺激CD4+T细胞反应的能力确定的伯内蒂弧菌蛋白将诱导与全细胞疫苗相同的对毒力攻击的保护；以及ii)使用这些定义的免疫刺激伯内蒂弧菌蛋白的免疫将显著降低疫苗接种后不良反应的发生率和严重性。这些假说将在三个特定目标中得到验证：1)在具有保护性的天然伯内蒂弧菌全细胞中鉴定新的T细胞免疫原；2)在伯内蒂弧菌菌株中保存T细胞免疫原；3)用伯内蒂弧菌抗原免疫，并确定对同源和异种菌株攻击的保护性免疫。

DESCRIPTION (provided by applicant): Coxiella burnetii, the etiological agent of "Q-fever", is a category-B bioterrorism agent that is highly infective to both humans and livestock. Human infection arises primarily from aerosol transmission and C. burnetii can withstand desiccation and remain infectious in contaminated soils for several years. Ease of dissemination via aerosol, environmental persistence, and high infectivity (ID50=1) make C. burnetii a serious threat for military personnel and civilians. This agent has already been weaponized and mass-produced under various biological warfare programs. Consequently, there is an urgent need to develop a vaccine that is effective and can be safely used for targeted or mass vaccination following a presumed or confirmed outbreak. Currently, there is no vaccine that meets these criteria-we propose a strategy to identify defined C. burnetti immunogens that meet these criteria. We propose to identify and test defined C. burnetti immunogens using a novel proteomic approach combined with screening for the required cell-mediated response, an approach that takes advantage of the recent completion of the Nine Mile strain genomic sequence. Intracellular killing of C. burnetti is mediated via IFN-gamma and is associated with strong stimulation of nitric oxide production. Consequently, vaccine induced immunity is dependent upon priming and expansion of CD4+ T lymphocytes that can recognize infected macrophages via MHC class II presentation of C. burnetti antigens and secrete high levels of IFN-gamma. In this project we will test the following hypotheses: i) that defined C. burnetii proteins, identified by ability to stimulate a CD4+ T cell response, will induce protection against virulent challenge equivalent to that induced by the whole-cell vaccine; and ii) that immunization using these defined, immunostimulatory C. burnetti proteins will significantly reduce the incidence and severity of post-vaccination adverse reactions. These hypotheses will be tested in three specific aims: 1] Identification of novel T cell immunogens in protective native C. burnetti whole cells; 2] Conservation of T cell immunogens among C. burnetti strains; and 3] Immunization with C. burnetii antigens and determination of protective immunity against homologous and heterologous strain challenge.