Mapping of F. tularensis T cell epitopes in Mice

描述（由申请方提供）：吸入细胞内革兰氏阴性菌土拉热弗朗西斯菌对人体具有高度致死性。自F.土拉热很容易被武器化 它被认为是最重要的潜在生物战剂之一。对F.土拉热的特征很不明确。到目前为止，F。土拉热活疫苗株（LVS）是来源于F.土拉热菌亚种全北极亚种（B型）在人类中表现出不同程度的保护作用。然而，由LVS菌株表达的保护性抗原尚未被表征，并且减毒的LVS不太可能通过当前疫苗安全标准的批准。因此，开发一种目前尚不可用的许可亚单位疫苗至关重要。鉴定F的候选T细胞表位是我们的长期目标。在“人源化”HLA-DR转基因小鼠中发现了土拉热菌，其可用于开发亚单位疫苗以在人类中诱导保护性免疫。背后的特定假设 本申请是F.土拉热可以在“人源化”HLA-DR转基因小鼠中鉴定，所述转基因小鼠也由人APC加工和呈递，并且可以用于亚单位疫苗的设计。我们将这一假设基于以下观察：首先，对弗朗西斯菌属感染的保护似乎严重依赖于特异性T细胞免疫和T细胞衍生的IFNg产生。第二，在用LVS接种后，在HLA-DR 4 tg小鼠中检测到剧烈的T细胞增殖和细胞因子产生。第三，在HLA-DR 4转基因小鼠中鉴定的自身抗原和微生物抗原的T细胞表位与人类相关。我们基于我们的初步数据表明，在“人源化”HLA-DR 4转基因小鼠中表征的T细胞表位由人HLA-DR 4 + APC加工和呈递，这一假设。因此，总的来说，我们认为HLA转基因动物提供了一种新的工具和模型，以确定T细胞决定簇的F。土拉热菌，这些细菌对人类疫苗的开发具有潜在的用途。我们将测试这个假设与 具体而言，我们将（1）表征F.在HLA-DR 4（DRB 1 *0401）转基因小鼠中诱导保护性T细胞免疫的土拉菌蛋白。(2)鉴定HLA-DR tg小鼠中的保护性T细胞肽表位。(3)检查HLA-DR tg小鼠呈递的表位是否也由人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.