Live Imaging of Immunity to M. tuberculosis

结核分枝杆菌免疫实时成像

• 批准号: 10326395
• 负责人: Joel D. Ernst
• 金额: $ 10.1万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-06 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10326395
• 关键词: Antigen Presentation; Antigens; Bacteria; C57BL/6 Mouse; CD4 Positive T Lymphocytes; CD8-Positive T-Lymphocytes; CD8B1 gene; California; Cell Communication; Cells; Chronic; Communicable Diseases; Development; Distant; Effectiveness; Environment; Event; Failure; Frequencies; Goals; Granuloma; HIV; Human; Image; Immune; Immunity; Infection; Knowledge; Light; Lung; Lymphocyte; Lymphocyte antigen; Lymphoid Cell; Mechanics; Medicine; Modeling; Molecular; Mus; Mycobacterium tuberculosis; Myeloid Cells; Nature; Peptide/MHC Complex; Phenotype; Play; Positioning Attribute; Reagent; Reporter; Research; Role; San Francisco; Signal Transduction; Site; Structure of parenchyma of lung; System; T cell response; T-Cell Development; T-Lymphocyte; Testing; Tissues; Tuberculosis; Tuberculosis Vaccines; Universities; Up-Regulation; Vaccines; Work; adaptive immune response; antigen-specific T cells; biosafety level 3 facility; chemokine receptor; chronic infection; design; experimental study; follow-up; immune checkpoint; in vivo; innovation; insight; intravital imaging; intravital microscopy; migration; multiphoton microscopy; nonhuman primate; pathogen; predictive modeling; receptor expression; receptor function; response; tool; tuberculosis immunity; vaccine trial

Project Summary Tuberculosis (TB), caused by the bacterium, Mycobacterium tuberculosis, kills more humans every year than does any other infectious disease, including HIV. Among the obstacles to eliminating TB is the lack of a sufficiently-efficacious vaccine. Despite strong evidence for essential roles of CD4 T cells in TB immunity, naturally-occurring T cell responses do not reliably eliminate the pathogen in TB, and we do not fully understand the mechanisms that limit the effectiveness of CD4 T cell responses to M. tuberculosis. In earlier work, we discovered that for optimal immune control, CD4 T cells must directly recognize and make intermolecular contacts with M. tuberculosis-infected cells at the site of infection in the lungs. In light of this requirement for intimate contact, we and others have found (in mice, nonhuman primates, and humans) that CD4 T cells are located at the periphery of granulomas, rather than in the core where infected cells reside. We therefore hypothesize that a major mechanism limiting immunity to TB is the failure of CD4 T cells to contact and engage with infected cells, and that overcoming this failure will increase the efficacy of T cell immunity to TB. Several potential mechanisms can explain the spatial separation of M. tuberculosis-infected cells and CD4 T cells in vivo, yet these are not amenable to analysis using fixed, static images or cells removed from the granuloma environment. Therefore, in this project, we propose to combine a unique multiphoton microscopy system for intravital imaging, contained in a Biosafety Level 3 facility at the IPBS in Toulouse, with unique reporter mice and M. tuberculosis strains developed and characterized at UCSF, to characterize interactions of antigen-specific CD4 T cells with M. tuberculosis-infected and bystander cells in the lungs of live mice. The combination of these innovative experimental systems allows us to test specific hypotheses that can account for the spatial and functional separation of CD4 T cells and M. tuberculosis-infected cells in the lungs. The knowledge gained from these studies will be used: 1) to inform design of experiments to define the molecular mechanisms that restrict CD4 T cell interactions with M. tuberculosis-infected cells in vivo; 2) to provide the basis for studies comparing distinct candidate TB vaccines, to determine which of them promote development of T cells that optimally access M. tuberculosis-infected cells in granuloma cores. In additional experiments, we will extend recent findings indicating important roles for innate lymphoid cells (ILC) in protective immunity to TB. Specifically, we will follow up on findings that type 2 ILC (ILC2) undergo dramatic phenotypic transformations to ILC1-like cells in vivo in response to M. tuberculosis infection, by live imaging of the interactions of ILC2 and ILC1-like cells with M. tuberculosis-infected cells and with CD4 T cells, during the initial and the chronic stages of infection. Our studies have high potential to provide valuable insights and new paradigms of immunity to TB, with the goal of informing development of efficacious vaccines and host-directed therapies.

项目概要 结核病 (TB) 由结核分枝杆菌引起，每年造成的死亡人数超过 是否患有任何其他传染病，包括艾滋病毒。消除结核病的障碍之一是缺乏 足够有效的疫苗。尽管有强有力的证据表明 CD4 T 细胞在结核病免疫中发挥重要作用， 自然发生的 T 细胞反应并不能可靠地消除结核病病原体，我们还不完全了解 限制 CD4 T 细胞对结核分枝杆菌反应有效性的机制。在早期的工作中，我们 发现为了获得最佳的免疫控制，CD4 T 细胞必须直接识别并产生分子间 与肺部感染部位的结核分枝杆菌感染细胞接触。鉴于这一要求 在亲密接触中，我们和其他人发现（在小鼠、非人类灵长类动物和人类中）CD4 T 细胞 位于肉芽肿的外围，而不是受感染细胞所在的核心。我们因此 假设限制结核病免疫力的一个主要机制是 CD4 T 细胞未能接触和参与 克服这种失败将提高 T 细胞对结核病的免疫功效。一些 潜在的机制可以解释结核分枝杆菌感染的细胞和CD4 T细胞在体内的空间分离， 然而，这些不适合使用固定的静态图像或从肉芽肿中取出的细胞进行分析 环境。因此，在这个项目中，我们建议结合一个独特的多光子显微镜系统 活体成像，位于图卢兹 IPBS 的生物安全 3 级设施中，配有独特的报告小鼠和 结核分枝杆菌菌株在加州大学旧金山分校开发并鉴定，以表征抗原特异性的相互作用 活小鼠肺部感染结核分枝杆菌的 CD4 T 细胞和旁观者细胞。这些的组合 创新的实验系统使我们能够测试可以解释空间和 肺中 CD4 T 细胞和结核分枝杆菌感染细胞的功能分离。所获得的知识来自 这些研究将用于：1）为实验设计提供信息，以确定限制的分子机制 CD4 T 细胞与体内结核分枝杆菌感染细胞的相互作用； 2）为研究比较提供基础 不同的候选结核疫苗，以确定哪些疫苗能够促进 T 细胞的发育，从而最佳地接触 肉芽肿核心中结核分枝杆菌感染的细胞。在其他实验中，我们将扩展最近的发现 表明先天淋巴细胞（ILC）在结核病保护性免疫中发挥重要作用。具体来说，我们将遵循 根据发现，2 型 ILC (ILC2) 在体内经历了向 ILC1 样细胞的戏剧性表型转变 通过实时成像 ILC2 和 ILC1 样细胞与结核分枝杆菌感染的相互作用。 在感染的初始阶段和慢性阶段，结核感染的细胞和CD4 T细胞。我们的研究 具有提供有价值的见解和结核病免疫新范式的巨大潜力，目的是为人们提供信息 开发有效的疫苗和针对宿主的疗法。