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细胞对于对结核病（TB）的免疫力至关重要，但提供的CD4 T细胞的特征 保护性免疫尚不清楚。这种知识差距部分归因于对M的知识有限。 结核病（MTB）抗原，可诱导受保护的免疫复杂。在其他病原体中，免疫识别 在某些抗原中，有保护，而对其他抗原的识别则没有。同样在其他病原体中 受保护免疫的抗原靶标会经历多样化的进化选择，以产生抗原 变异和逃避免疫识别。我们假设这些原则适用于MTB，并在以前 我们的研究意外发现，人类T细胞的常见抗原靶标 MTB中的（表位）受到了过度保守；它们是MTB基因组中最保守的元素。然后我们 试图找到例外，并结合了MTB的系统发育不同菌株的比较基因组学 实验免疫学。这导致我们发现了七个新型MTB抗原（我们称MTB稀有变量 抗原； RVA）被人类T细胞识别，并且暴露了进化多样的选择的证据。 总之，这些结果表明，RVA的人类T细胞识别对MTB有害，并且识别 保守的“经典” MTB抗原并不损害MTB。我们最近研究了健康的CD4 T细胞 TB的Quantiferon-TB阳性（QFT+）最近与TB感染病例的密切接触，发现RVA影响 CD4 T细胞的特征是主要白细胞介素17的反应和谱系定义的表达 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 T-bet的伽马响应和表达。这些结果表明识别RVA的人CD4 T细胞 在功能上与识别保守抗原的抗原的功能不同，我们假设T细胞 公认的RVA提供了针对主动结核的保护，如其进化选择所示。在这个项目中， 我们将通过比较特征来强烈地使用创新的Assas来深入地表征QFT+成人的CD4 T细胞 识别RVA与经典MTB抗原的CD4 T细胞的。我们将比较他们的功能响应， 纵向记忆表型和分化程度。我们还将采用创新的新平台 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是 MTB的宽度。为了确定RVA在保护性免疫对结核病方面的重要性，我们将比较CD4 T 识别具有活性结核病成人的RVA与经典MTB抗原的细胞和具有“控制”（或潜在）的细胞 TB。我们还将检验以下假设：RVA特异性CD4 T细胞中的缺陷是主要的，并且不会逆转 主动结核病的处理。该项目的长期目标是告知结核病疫苗的开发 防止导致人类发病率和死亡率的形式进展到活跃的结核病疾病，以及 负责结核病传输。