Mapping of F. tularensis T cell epitopes in Mice

描述(由申请人提供)：吸入细胞内的革兰氏阴性杆菌图拉氏方济各菌对人类具有高度的致命性。由于图拉氏丝虫很容易被武器化 将其雾化，被认为是最重要的潜在生物杀菌剂之一。图拉氏肺吸虫的毒力决定因素和保护性抗原的特性一直很差。到目前为止，图拉氏丝虫活疫苗株(LVS)来自图拉氏丝虫亚种Holarctica(B型)，已证明对人类有不同程度的保护作用。然而，LVS株表达的保护性抗原尚未确定，减毒的LVS不太可能通过当前疫苗安全标准的批准。因此，目前还没有获得许可的亚单位疫苗的开发是至关重要的。我们的长期目标是在人源化的人类白细胞抗原-DR转基因小鼠中识别图拉氏丝虫的候选T细胞表位，以用于开发亚单位疫苗以诱导人类保护性免疫。其背后的具体假设 这一应用是可以在人源化的HLA-DR转基因小鼠中识别图拉氏肺吸虫的保护性T细胞表位，这些转基因小鼠也是由人的APC加工和呈递的，可以用于亚单位疫苗的设计。我们基于以下观察结果提出这一假设：首先，对弗朗西塞氏菌感染的保护似乎严重依赖于特定的T细胞免疫和IFNG产生的T细胞。第二，接种LVS后，HL A-DR4Tg小鼠T细胞增殖和细胞因子产生明显增强。第三，在人类白细胞抗原-DR4转基因小鼠中发现的自身和微生物抗原的T细胞表位与人类相关。我们基于我们的初步数据，表明“人源化”的HLA-DR4转基因小鼠的T细胞表位是由人的HLA-DR4 APC处理和呈递的。因此，总体而言，我们认为，人类白细胞抗原转基因动物提供了一种新的工具和模型来鉴定图拉氏丝虫的T细胞决定簇，这些决定簇具有开发人类疫苗的潜在用途。我们将使用 具体来说，我们将(1)鉴定在人类白细胞抗原-DR4(DRB1*0401)转基因小鼠中诱导保护性T细胞免疫的图拉氏F菌蛋白。(2)鉴定人类白细胞抗原DR Tg小鼠的保护性T细胞表位。(3)检测HLADR-Tg小鼠提出的抗原表位是否也由人类APC呈递。

DESCRIPTION (provided by applicant): Inhalation of the intracellular gram-negative bacterium Francisella tularensis is highly fatal in humans. Since F. tularensis can be easily weaponized into an aerosolized form, it is considered to be one of the most important potential biowarfare agents. The virulence determinants and protective antigens of F. tularensis have been poorly characterized. To date, the F. tularensis live vaccine strain (LVS), which is derived from F. tularensis subspecies holarctica (type B), has demonstrated varying degrees of protection in humans. However, the protective antigens expressed by the LVS strain have yet to be characterized, and attenuated LVS is unlikely to pass approval for current safety standards for vaccines. Therefore, development of a licensed subunit vaccine, which is currently not available, is of utmost importance. It is our long-term goal to identify candidate T cell epitopes of F. tularensis in "humanized" HLA-DR transgenic mice that can be used to develop subunit vaccines to induce protective immunity in humans. The specific hypothesis underlying this application is that protective T cell epitopes of F. tularensis can be identified in "humanized" HLA-DR transgenic mice that are also processed and presented by human APCs and could be used for the design of a subunit vaccine. We base this hypothesis on the following observations: First, protection to Francisella infection appears to be critically dependent on specific T cell immunity and T cell-derived production of IFNg. Second, vigorous T cell proliferation and cytokine production was detected in HLA-DR4 tg mice upon vaccination with LVS. Third, T cell epitopes of self- and microbial antigens identified in the HLA-DR4 transgenic mice are relevant to humans. We base this assumption on our preliminary data showing that T cell epitopes characterized in "humanized" HLA-DR4 transgenic mice are processed and presented by human HLA-DR4+ APCs. Thus, overall, we believe that the HLA transgenic animals provide a novel tool and model to identify T cell determinants of F. tularensis that have potential use for the development of vaccines for humans. We will test this hypothesis with the following specific aims: Specifically, we will (1) characterize the F. tularensis proteins that induce protective T cell immunity in HLA-DR4 (DRB1*0401) ransgenic mice. (2) Identify protective T cell peptide epitopes in the HLA-DR tg mice. (3) Examine whether epitopes presented by the HLA-DR tg mice are also presented by human APCs.