Innate Immune Effectors in Early Immune Response to Mycobacterium Tuberculosis

描述（由申请人提供）： 结核分枝杆菌（Mtb）感染了全世界约三分之一的人口。据估计，每年发生800万新病例和200万死亡病例，使结核病成为一个重大的健康问题。目前的结核病疫苗在预防结核病传播方面无效。此外，越来越多的美国军事人员被部署到结核病流行地区，如阿富汗。迫切需要开发一种有效的Mtb疫苗，这将需要更好地理解对控制该疾病至关重要的细胞免疫应答。虽然适应性细胞免疫应答在TB的宿主控制中是必不可少的，但导致对Mtb的最佳适应性细胞免疫应答所需的许多先天免疫机制仍有待表征。结核病是通过气溶胶接触而感染的，大多数结核病病例完全是肺部的。尽管如此，对暴露于人气道和肺中的结核分枝杆菌后发生的早期事件知之甚少，并且缺乏对人类初始感染的基本表征。在暴露于结核分枝杆菌时，排列在气道中的上皮细胞是最有可能遇到雾化细菌的细胞。我们最近确定，原代人大气道上皮细胞一旦感染结核分枝杆菌，可以作为先天性T细胞群的目标，称为粘膜相关的不变T（MAIT）细胞，优先定位于肺。这项研究的长期目标是确定在人类气道和肺中对Mtb的早期免疫应答中发挥作用的先天细胞效应物。在目标1中，我们希望定义人类气道中可以被Mtb感染的细胞，然后确定哪些细胞可以激活先天MAIT细胞。AIM 1.识别被Mtb感染的气道细胞和那些激活先天MAIT细胞的细胞。假设：先天MAIT细胞是Mtb感染细胞SA 1a的一般检测器。使用免疫荧光和共聚焦显微镜，以确定Mtb定位在气道组织SA 1b。识别可被Mtb感染的气道细胞并激活先天性MAIT细胞粘膜部位的上皮细胞提供了对抗外来病原体的第一道防线。气道树突状细胞（DC），在启动随后的适应性免疫的基本要素，位于上下的上皮基底成员。在Mtb感染中，DC在引发对控制病原体至关重要的Mtb特异性适应性T细胞中是必需的。在这个提议中，我们想解决的关键问题是DC如何获得气道中的Mtb抗原，以及先天性T细胞是否可以增强抗原呈递。AIM 2.确定气道树突状细胞（DC）如何获得Mtb抗原。假设：树突状细胞从Mtb感染的气道上皮细胞获得Mtb抗原。SA2a。评估DC如何从上皮细胞SA 2b获得Mtb抗原。确定MAIT细胞在DC的抗原呈递中的作用我们已经表明，MAIT细胞构成了人类Mtb反应性非经典CD 8 + T细胞应答的可证实的比例。然而，我们的工作表明，其他非经典的CD 8 + T细胞群体仍有待鉴定。在目标3中，我们建议克隆和表征这些非经典的结核分枝杆菌反应性CD 8 + T细胞，以进一步确定人类先天性T细胞对结核分枝杆菌的反应。AIM 3.表征非经典限制性Mtb反应性T细胞的未定义子集。假设：非经典非MAIT Mtb反应性T细胞代表新的先天性T细胞亚群。SA 3a。克隆和表征Mtb反应性的非MAIT CD 8 + 34 TCR-T细胞

DESCRIPTION (provided by applicant): Mycobacterium tuberculosis (Mtb) infects about one third of the population worldwide. An estimated 8 million new cases and 2 million deaths occur annually placing tuberculosis (TB) as a significant health problem. The current vaccine for TB is ineffective in preventing transmission of TB. Furthermore, an increasing number of US military personnel are being deployed to TB endemic regions such as Afghanistan. There is an urgent need to develop of an efficacious vaccine for Mtb that will require a better understanding of the cellular immune response that is critical to control the disease. While the adaptive cellular immune response is essential in the host control of TB, many of the innate immune mechanisms that are required to result in an optimal adaptive cellular immune response to Mtb remain to be characterized. Mtb is contracted by aerosol exposure and the majority of TB cases are exclusively pulmonary. Nonetheless, little is known about the early events that occur after exposure to Mtb in the human airway and lung and basic characterization of the initial infection in humans is lacking. Upon exposure to Mtb, the epithelial cells that line the airways are the cells most likely to encounter the aerosolized bacteria. We recently determined that primary human large airway epithelial cells once infected with Mtb can serve as targets for an innate T cell population known as mucosal associated invariant T (MAIT) cells that preferentially localizes to the lung. The long-term goal of this research is to identify the innate cellular effectors that play a role in the early immune response to Mtb in the human airway and lung. In Aim 1 we want to define the cells in the human airway that can be infected with Mtb and then determine which of those cells can activate innate MAIT cells. AIM 1. Identify the airway cells that are infected with Mtb and those that activate innate MAIT cells. Hypothesis: Innate MAIT cells are general detectors of Mtb-infected cells SA1a. Use immunofluorescence and confocal microscopy to identify where Mtb localizes in airway tissue SA1b. Identify airway cells that can be infected with Mtb and activate innate MAIT cells Epithelial cells at mucosal sites provide a first line of defense against foreign pathogens. Airway dendritic cells (DC), an essential element in priming subsequent adaptive immunity, are located above and below the basement member of the epithelium. In infection with Mtb, DC are essential in priming the Mtb-specific adaptive T cells that are crucial to control the pathogen. In this proposal we want to address the key question of how DC acquire Mtb antigens in the airway and if innate T cells can enhance antigen presentation. AIM 2. Determine how airway dendritic cells (DC) acquire Mtb antigens. Hypothesis: Dendritic cells acquire Mtb antigens from Mtb-infected airway epithelial cells. SA2a. Assess how DC acquire Mtb antigens from epithelial cells SA2b. Determine the role of MAIT cells in antigen presentation by DC We have shown that MAIT cells make up a demonstrable proportion of the Mtb-reactive nonclassical CD8+ T cell response in humans. However, our work suggests that additional nonclassical CD8+ T cell populations remain to be characterized. In Aim 3 we propose to clone and characterize these nonclassical Mtb-reactive CD8+ T cells to further define the innate T cell response to Mtb in humans. AIM 3. Characterize undefined subsets of nonclassically restricted Mtb-reactive T cells. Hypothesis: Nonclassical non-MAIT Mtb-reactive T cells represent novel innate T cell subsets. SA3a. Clone and characterize non-MAIT CD8+ 34 TCR- T cells that are Mtb-reactive