Mechanistic investigation of differential T cell responses to distinct Mycobacterium tuberculosis antigens

T 细胞对不同结核分枝杆菌抗原的差异反应的机制研究

• 批准号: 10536054
• 负责人: Zachary Howard
• 金额: $ 4.26万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10536054
• 关键词: Adoptive Transfer; Animal Model; Antigen Targeting; Antigenic Variation; Antigens; BCG Live; Bacteria; CD4 Positive T Lymphocytes; Cessation of life; Clinical; Clinical Trials; DNA Vaccines; Data; Development; Disease; Drug resistance; Epidemiology; Exhibits; Flow Cytometry; Genes; Genome; Goals; Human; Immune; Immune Evasion; Immune response; Immunofluorescence Microscopy; Immunohistochemistry; Individual; Infection; Infection prevention; Inflammation; Inflammatory; Investigation; Laboratories; Lead; Lung; Lymphoid; Mediating; Mediator of activation protein; Mus; Mutation; Mycobacterium tuberculosis; Mycobacterium tuberculosis antigens; Myelogenous; Peptide/MHC Complex; Phenotype; Phylogenetic Analysis; Population; Pulmonary Inflammation; Pulmonary Tuberculosis; Role; T cell receptor repertoire sequencing; T cell response; T-Lymphocyte; T-Lymphocyte Epitopes; T-Lymphocyte Subsets; Testing; Tuberculosis; Tuberculosis Vaccines; Vaccinated; Vaccination; Vaccine Antigen; Vaccines; Variant; Work; antigen challenge; antigen-specific T cells; coronavirus disease; disorder prevention; effector T cell; genome analysis; global health; human model; immunopathology; immunoregulation; improved; novel; pathogen; pressure; prevent; response; single-cell RNA sequencing; transmission process; vaccine development; vaccine response

Abstract Tuberculosis (TB) is a major global health threat and the only licensed TB vaccine, Bacille Calmette-Guérin (BCG), is inadequate: despite widespread use of BCG, there were 9.9 million new TB cases globally in 2020. Thus, improved vaccines against Mtb are urgently needed. T cell responses remain the primary goal of TB vaccines, as CD4 T cells are necessary to control Mtb in humans and animal models. T cell vaccines have been thus far unsuccessful in preventing infection, but the recent clinical trial of M72-AS01E demonstrated ~50% efficacy as a Prevention of Disease (POD) vaccine. Since TB is transmitted by those with active disease, which is characterized by inflammation and immunopathology, a vaccine that reduces or prevents active disease and immunopathology can have a large impact on the global problem of TB. However, the most optimal antigen target(s) for TB vaccines are not defined, and the lack of evolutionary variation in the known antigens of Mtb suggests that T cell recognition of those antigens is not detrimental to the pathogen or beneficial to the host. Through a comprehensive analysis of genomes from 216 phylogenetically diverse Mtb, my advisor and his colleagues discovered a distinct subset of Mtb antigens that are sequence variable and exhibit evidence of evolutionary selection pressure. In a screen of DNA vaccines encoding these sequence variable antigens, I discovered one (encoding 4 sequence variable antigens) that alters immunopathology and inflammatory Th1 responses in mice subsequently challenged with Mtb, without reducing lung bacterial burdens. Additional studies in our laboratory have demonstrated distinct CD4 T cell effector responses to these same antigens in humans. From these and other results, we hypothesize that a functionally distinct T cell response to one or more of our vaccine antigens is responsible for altered immunopathology in vaccinated mice after challenge. The objective of this proposal is to characterize the cellular responses in vaccinated mice after challenge and identify the mechanism that accounts for altered immunopathology. I will characterize the cellular response using spectral flow cytometry and immunofluorescence microscopy. I will then characterize the vaccine-specific T cell response using peptide:MHC tetramers and single cell RNA sequencing to identify potential mechanisms mediating the altered immunopathology response. Finally, I will identify the underlying mechanism(s) by performing adoptive transfers of sorted T cells to identify the phenotype of the T cells that alter immunopathology during infection. This work will identify differential T cell responses to distinct Mtb antigens and demonstrate a role of immunoregulation in mediating a vaccine response to Mtb infection. The findings will provide an understanding of T cell responses to Mtb antigens that can modulate immunopathology. This will provide a framework of vaccine-induced immunoregulatory responses to inform development of POD vaccines for Mtb.

摘要 结核病（TB）是一个主要的全球性健康威胁，唯一获得许可的结核病疫苗是Bacille Calmette-Guérin。 (BCG)尽管BCG得到广泛使用，但2020年全球仍有990万新发结核病病例。 因此，迫切需要针对Mtb的改进的疫苗。T细胞反应仍然是结核病的主要目标 疫苗，因为CD 4 T细胞是控制人类和动物模型中的Mtb所必需的。T细胞疫苗已经 迄今为止，在预防感染方面并不成功，但最近的M72-AS 01 E临床试验显示， 作为疾病预防（POD）疫苗的有效性。由于结核病是由活动性疾病传播的， 以炎症和免疫病理学为特征，是减少或预防活动性疾病的疫苗， 免疫病理学可以对结核病的全球问题产生很大影响。然而，最理想的抗原 结核病疫苗的靶点尚未确定，已知的结核分枝杆菌抗原缺乏进化变异， 表明T细胞识别这些抗原对病原体无害或对宿主有益。 通过对216个遗传多样性Mtb的基因组进行全面分析，我的顾问和他的顾问 他的同事发现了一个独特的Mtb抗原子集，它们是序列可变的，并显示出 进化选择压力在编码这些序列可变抗原的DNA疫苗的筛选中， 发现了一种（编码4种序列可变抗原），可改变免疫病理学和炎性Th 1 在随后用Mtb攻击的小鼠中的应答，而不降低肺细菌负荷。其他研究 在我们的实验室中已经证明了不同的CD 4 T细胞效应器响应这些相同的抗原在人类中。 根据这些和其他结果，我们假设功能不同的T细胞对我们的一种或多种免疫应答可能是一种免疫应答。 疫苗抗原负责攻击后接种的小鼠中免疫病理学的改变。客观 该建议的目的是表征接种疫苗的小鼠在攻击后的细胞反应，并确定 解释免疫病理学改变的机制。我会用光谱分析来描述细胞反应 流式细胞术和免疫荧光显微术。然后我将描述疫苗特异性T细胞反应 使用肽：MHC四聚体和单细胞RNA测序，以确定潜在的机制，介导 改变免疫病理学反应。最后，我将通过执行采用 转移分选的T细胞以鉴定在感染期间改变免疫病理学的T细胞表型。 这项工作将确定不同的T细胞反应不同的结核分枝杆菌抗原和证明的作用， 免疫调节在介导疫苗对Mtb感染的应答中的作用。研究结果将提供一个理解 T细胞对Mtb抗原的反应可以调节免疫病理学。这将提供一个框架 疫苗诱导的免疫调节反应，为Mtb的POD疫苗的开发提供信息。