Functionally distinct human CD4 T cell responses to novel evolutionarily selected M. tuberculosis antigens

功能独特的人类 CD4 T 细胞对新型进化选择的结核分枝杆菌抗原的反应

• 批准号: 10735075
• 负责人: Joel D. Ernst
• 金额: $ 85.51万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2028-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10735075
• 关键词: Adult; Aftercare; Antibodies; Antigen Presentation; Antigenic Variation; Antigens; Bar Codes; Biological Assay; CD4 Positive T Lymphocytes; Cell physiology; Characteristics; Cytoprotection; DNA; Defect; Development; Disease; Elements; Epitopes; Exhibits; Frequencies; Gene Expression Profile; Genome; Goals; Human; IL17 gene; Immune; Immune response; Immunity; Immunology; Individual; Infection; Interferon Type II; Knowledge; M. tuberculosis genome; Memory; Modeling; Mus; Mycobacterium tuberculosis; Mycobacterium tuberculosis antigens; Open Reading Frames; Participant; Peptide Library; Peptides; Phenotype; Phylogenetic Analysis; Population; Property; Proteome; Specificity; T cell response; T memory cell; T-Lymphocyte; T-Lymphocyte Epitopes; Testing; Tuberculosis; Tuberculosis Vaccines; Work; active method; comparative genomics; disorder prevention; genomic locus; human morbidity; human mortality; innovation; insight; neoplastic cell; new technology; next generation sequencing; novel; pathogen; pressure; prevent; receptor expression; response; transcription factor; transmission process; tuberculosis immunity; vaccine development

Although CD4 T cells are essential for immunity to tuberculosis (TB), the features of CD4 T cells that provide protective immunity are not well understood. This knowledge gap is due in part to limited knowledge of the M. tuberculosis (Mtb) antigens that induce protective immune responses. In other pathogens, immune recognition of some antigens provides protection, while recognition of other antigens does not. Likewise in other pathogens, the antigenic targets of protective immunity undergo diversifying evolutionary selection to generate antigenic variation and escape immune recognition. We hypothesized that these principles apply to Mtb, and in earlier studies we made the unexpected discovery that the commonly-studied antigenic targets of human T cells (epitopes) in Mtb are hyperconserved; they are the most conserved elements of the Mtb genome. We then sought to find exceptions, and combined comparative genomics of phylogenetically diverse strains of Mtb with experimental immunology. This led to our discovery of seven novel Mtb antigens (that we term Mtb Rare Variable Antigens; RVA) that are recognized by human T cells and exhibit evidence of evolutionary diversifying selection. Together, these results suggest that human T cell recognition of RVA is detrimental to Mtb and that recognition of conserved 'classical' Mtb antigens is not detrimental to Mtb. We recently studied CD4 T cells from healthy Quantiferon-TB positive (QFT+) recent close contacts of infectious cases of TB, and discovered that RVA induce CD4 T cells characterized by dominant interleukin 17 responses and expression of the lineage-defining transcription factor RORγt, in contrast to CD4 T cells that recognize classical Mtb antigens and exhibit interferon gamma responses and expression of T-bet. These results indicate that human CD4 T cells that recognize RVA are functionally distinct from those that recognize conserved antigens, and we hypothesize that T cells that recognize RVA provide protection against active TB, as indicated by their evolutionary selection. In this project, we will use innovative assays to intensively characterize CD4 T cells from QFT+ adults by comparing the features of CD4 T cells that recognize RVA versus classical Mtb antigens. We will compare their functional responses, longitudinal memory phenotypes, and extent of differentiation. We will also employ an innovative new platform developed by our team, using DNA barcoded peptide epitopes and next generation sequencing to test the hypothesis that associations between CD4 T cell antigen specificity and certain functional responses are widespread in Mtb. To determine the significance of RVA in protective immunity to TB, we will compare CD4 T cells that recognize RVA vs classical Mtb antigens in adults with active TB and those with 'controlled' (or latent) TB. We will also test the hypothesis that defects in RVA-specific CD4 T cells are primary and do not reverse with treatment of active TB. The long term objective of this project is to inform development of TB vaccines that prevent progression to active TB disease, the form that causes human morbidity and mortality, and the form that is responsible for TB transmission.

尽管 CD4 T 细胞对于结核病 (TB) 免疫至关重要，但 CD4 T 细胞的特性可提供 这种知识差距部分是由于对 M 的了解有限。 结核病 (Mtb) 抗原可在其他病原体中诱导保护性免疫反应、免疫识别。 某些抗原的识别可以提供保护，而其他抗原的识别则不能提供保护。 保护性免疫的抗原靶标经历多样化的进化选择以产生抗原 我们进化出这些原则适用于 Mtb，并且在早期。 研究中我们意外地发现人类 T 细胞的常见抗原靶标 Mtb 中的（表位）是高度保守的；它们是 Mtb 基因组中最保守的元件。 试图寻找例外，并将系统发育多样化的 Mtb 菌株的比较基因组学与 这导致我们发现了七种新型 Mtb 抗原（我们称之为 Mtb 稀有变异）。 抗原；RVA）被人类 T 细胞识别并表现出进化多样化选择的证据。 总之，这些结果表明人类 T 细胞对 RVA 的识别对 Mtb 来说是一种痛苦，并且这种识别 我们最近研究了来自健康人的 CD4 T 细胞。 Quantiferon-TB 阳性（QFT+）最近与结核感染病例有密切接触，并发现 RVA 诱发 CD4 T 细胞以显性白细胞介素 17 反应和谱系定义表达为特征 转录因子 RORγt，与识别经典 Mtb 抗原并表现出干扰素的 CD4 T 细胞相反 γ 反应和 T-bet 表达表明人类 CD4 T 细胞识别 RVA 的结果。 在功能上与识别保守抗原的 T 细胞不同，我们捕获了能够识别保守抗原的 T 细胞 认识到 RVA 可以提供针对活动性结核病的保护，正如其进化选择所表明的那样。 我们将使用创新的检测方法，通过比较特征来深入表征 QFT+ 成人的 CD4 T 细胞 识别 RVA 与经典 Mtb 抗原的 CD4 T 细胞的功能反应， 纵向记忆表型和分化程度我们还将采用一个创新的新平台。 由我们的团队开发，使用DNA条形码肽表位和下一代测序来测试 假设 CD4 T 细胞抗原特异性与某些功能反应之间的关联 为了确定 RVA 在结核病保护性免疫中的重要性，我们将比较 CD4 T。 识别患有活动性结核病和“受控”（或潜伏）成人结核病的 RVA 与经典 Mtb 抗原的细胞 我们还将检验 RVA 特异性 CD4 T 细胞的缺陷是原发性的并且不会逆转的假设。 该项目的长期目标是为结核病疫苗的开发提供信息。 预防进展为活动性结核病、导致人类发病和死亡的形式以及 负责结核病的传播。