The cellular mechanisms of immunological memory development in COVID-19 patients

COVID-19患者免疫记忆发展的细胞机制

• 批准号: 10745497
• 负责人: WEIGUO CUI
• 金额: $ 32.14万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10745497
• 关键词: cellular; mechanisms; immunological; memory; development

The recent unexpected emergence of the COVID-19 pandemic has spurred significant interest in an improved understanding of immunological memory to SARS-CoV-2, which consists of humoral (neutralizing antibodies) and cellular (T and B cells) memory. The generation of immunological memory to the SARS-CoV-2 virus critically depends on T cell responses. During a viral infection, CD4 helper T cells differentiate largely into either Th1 cells that orchestrate a type I antiviral immune response or follicular helper (Tfh) cells that enhance antibody production. CD8 T cells clonally expand and acquire effector function to directly kill virus-infected cells. Despite the heterogeneity and clonal diversity of virus-specific T cells, the majority of effector T cells die after viral clearance and only a small portion of them develop into memory T cells that provide long-lasting protection for the host. Similarly, B cells develop into memory B cells and long-lived plasma cells that produce neutralizing antibodies. Snapshot observations with multi-parameter flow cytometry-based assays along the course of infection has yielded abundant knowledge of T cell phenotypic and functional diversity. However, approaches as such fail to address the developmental trajectory of virus-specific T cells. This becomes more obvious in human studies given that lineage tracing by genetic alterations or adoptive transfer experiments, done easily in mice, are inherently difficult or impossible in humans. In this proposal, we will first combine newly developed single- cell RNA sequencing (scRNA-seq) and T cell receptor sequencing (TCR-seq) techniques on the same cells and use TCR sequences as natural barcodes to directly “lineage trace” each patient’s SARS-CoV-2-specific CD4 and CD8 T cell effector response and memory formation at the single-cell level throughout the course of natural infection. Furthermore, we will perform gene regulatory network (GRN) analysis to delineate which transcription factors collaboratively regulate virus-specific CD4 and CD8 T cell differentiation trajectories. Next, we will measure T cell clonal diversity and the quality of T cell memory from COVID-19 patients as well as healthy human controls. The latter will be used to gauge the possible presence of pre-existing immunity (PEI) in the form of memory T cells derived from cross-reactivity to common coronaviruses. These measurements will use high- throughput RNA-seq of TCR amplicons and scRNA-seq of memory T cells from recall cultures as inputs for computational TCR motif analysis. Lastly, successful vaccine development relies on an advanced understanding of the types of Tfh cells that are generated during natural infection and how they interact with B cells as well as T regulatory cells for anti-SARS-CoV-2 antibody production in humans. To this end, we propose to monitor circulating Tfh cells, including three major populations (Th1-, Th2- and Th17-like subsets), and T follicular regulatory (Tfr) cells in both SARS-Cov-2-infected and healthy human control subjects. In addition, we will perform T cell-B cell coculture assays to dissect the functional contributions of each subset of Tfh cells and how they interact with Tfr cells in regulating anti-SARS-CoV-2 neutralizing antibody responses.

COVID-19大流行最近出现的意外出现引起了人们对改善的重大兴趣 对SARS-COV-2的免疫记忆的理解，该记忆由体液组成（中和抗体） 和细胞（T和B细胞）记忆。 取决于病毒感染期间的T细胞反应。 策划了I型抗抗免疫反应或卵泡辅助器（TFH）细胞，以增强抗体 生产CD8 T细胞在基础上膨胀和获取效应器。 病毒特异性T细胞的异质性和克隆多样性，大多数效应T细胞在病毒后死亡 清除和一小部分的清除成长为T细胞，可为持续的保护 同样，宿主的B细胞发展成记忆B细胞和长期生存的浆细胞 抗体。 感染产生了很多T细胞表型和功能多样性 这种未能解决病毒特异性T细胞的发育轨迹。 鉴于在小鼠中轻松进行的遗传改变或产物转移实验的谱系追踪， 在人类中本质上是困难或不可能的。 在同一细胞和 使用TCR序列作为天然条形码直接“谱系跟踪”每个患者的SARS-COV-2特异性CD4 和CD8 T细胞效应子的响应和单细胞级别的记忆形成自然的过程 此外，我们将执行定期网络（GRN）分析 因素协作调节病毒特异性CD4和CD8 T细胞区分轨迹。 测量T细胞细胞克隆多样性和来自COVID-19患者的细胞记忆以及健康 人类控制。 从交叉反应到常见的冠状动脉的记忆T细胞。 TCR扩增子的吞吐量RNA-seq和从经济培养物中的Mells的scrna-seq作为输入 计算TCR主题分析。 在自然感染期间与B细胞一起产生的TFH细胞类型的类型 抗SARS-COV-2抗体产生的T调节细胞，我们建议监测 循环TFH细胞，包括三个主要种群（Th1-，Th2和Th17样子集）和T卵泡 SARS-COV-2感染和健康的人类对照受试者中的调节剂（TFR）。 执行T-Cell-B细胞共培养分析，以剖析每个TFH细胞的每个子集的功能贡献以及如何 它们与TFR细胞相互作用，以调节抗SARS-COV-2中和抗体反应。