Immune evasion by SARS-CoV-2: the role of HLA class I

SARS-CoV-2 的免疫逃避：HLA I 类的作用

• 批准号: 10575292
• 负责人: MARLENE BOUVIER
• 金额: $ 23.99万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-11-17 至 2024-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10575292
• 关键词: 2019-nCoV; Address; Affect; Alleles; Antigen Presentation; Binding; Biological Assay; Biology; CD8-Positive T-Lymphocytes; COVID-19; COVID-19 pathogenesis; COVID-19 treatment; Cell surface; Cells; Cellular Immunity; Characteristics; Code; Complex; Coronavirus; Crystallization; Data; Development; Diagnosis; Disease; Down-Regulation; Endowment; Epitopes; Evaluation; Flow Cytometry; Future; Genomic Segment; Goals; Growth; HLA-A gene; HLA-B Antigens; HLA-C Antigens; Histocompatibility; Histocompatibility Antigens Class I; Immune; Immune Evasion; Impairment; In Vitro; Innate Immune Response; Interferon Type I; Investigation; Knowledge; Mediating; Molecular; Morbidity - disease rate; Mutation; NK Cell Activation; Natural Immunity; Natural Killer Cells; Nuclear; Open Reading Frames; Pathogenesis; Pathologic; Pathway interactions; Patients; Phenotype; Proteins; Research; Role; SARS coronavirus; SARS-CoV-2 genome; SARS-CoV-2 infection; SARS-CoV-2 pathogenesis; Scheme; Specificity; Structure; Surface; System; T cell response; Variant; Viral; Virulence; Virus; Virus Replication; adaptive immune response; adaptive immunity; antiviral immunity; cellular transduction; clinically relevant; current pandemic; exhaustion; experience; gel electrophoresis; human pathogen; immune function; in vivo; innovation; interest; mortality; mutant; novel; novel therapeutics; pandemic coronavirus; pandemic disease; pathogen; pressure; prevent; protein protein interaction; response; severe COVID-19; small molecule inhibitor; therapeutic development

ABSTRACT Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is responsible for the current pandemic of coronavirus-induced disease 2019 (COVID-19). Since December 2019, coordinated research efforts have provided a wealth of critical data that have enhanced our ability to diagnose and treat COVID-19. To date, however, much of the molecular and cellular mechanisms underlying the pathogenesis of COVID-19 remain elusive. The genome of SARS-CoV-2 contains nine independent open reading frames (ORFs) coding for proteins that are not essential for viral replication but seem to exert important functions in modulating host antiviral immunity. Of these accessory proteins, the ORF8 protein stands out for its unique characteristics. ORF8 is a highly variable protein among SARS-related CoVs. ORF8 also appears to be involved in a network of host-pathogen interactions inside infected cells: ORF8 impairs immune pathways such as antigen presentation, interferon type I, and nuclear factor-kB, as well as possibly activate growth pathways. A central question is how ORF8 mediates interactions with multiple host protein targets. Towards this goal, we are investigating ORF8 interaction with major histocompatibility class I (MHC I) molecules. It was shown recently that SARS-CoV-2 ORF8 suppresses CD8+ T cell responses by downregulating MHC I molecules, both in vitro and in vivo. We hypothesize that ORF8 suppresses surface expression of HLA-A and HLA-B molecules to protect infected cells from recognition by CD8+ T cells, but spares HLA-C and HLA-E to avoid activation of natural killer (NK) cells. The possibility that ORF8 displays a locus specificity toward MHC I would provide a mechanism for SARS-CoV-2 to walk a fine line between adaptive and innate immunity. Specifically, we will undertake an analysis of interactions between ORF8 and MHC I by using a panel of HLA- A, -B, -C, and -E molecules, and also determine if ORF8 selectively downregulates MHC I in relevant cell systems (Aim 1). We will extend these studies to ORF8 variants that have been positively selected during the course of the pandemic and evaluate if and how these mutations affect MHC I binding and downregulation (Aim 2). The successful completion of these Aims is expected to uncover unknown features of ORF8 and elucidate its role in suppressing antigen presentation, as well as inform us on the selective pressure that MHC I exerts on SARS-CoV-2. The immediate and long-term impact of our proposed research is high. This is the first study that: (1) characterizes molecular interaction of ORF8 with a host protein; and (2) evaluates clinically relevant ORF8 variants. By studying the immune interactions underlying ORF8-mediated downregulation of MHC I, we will increase our understanding of how SARS-CoV-2 derails cellular immunity. Importantly, our study will stimulate similar investigations of other ORF8-interactors, providing novel opportunities for the development of therapeutics directed against ORF8 or its host targets.

摘要 严重急性呼吸系统综合征冠状病毒2型（SARS-CoV-2）是造成目前大流行的原因 2019年冠状病毒引起的疾病（COVID-19）。自2019年12月以来，协调的研究工作 提供了丰富的关键数据，增强了我们诊断和治疗COVID-19的能力。到目前为止， 然而，COVID-19发病机制的许多分子和细胞机制仍然存在， 难以捉摸。SARS-CoV-2的基因组包含9个独立的开放阅读框（ORF），编码 对病毒复制不是必需的但似乎在调节宿主中发挥重要功能的蛋白质 抗病毒免疫在这些辅助蛋白中，ORF 8蛋白因其独特的特性而脱颖而出。 ORF 8是SARS相关冠状病毒中高度可变的蛋白。ORF 8似乎也参与了一个网络， 受感染细胞内宿主-病原体相互作用：ORF 8损害免疫途径，如抗原 呈递、I型干扰素和核因子-kB，以及可能激活生长途径。中央 问题是ORF 8如何介导与多个宿主蛋白质靶标的相互作用。为了实现这一目标，我们 研究ORF 8与主要组织相容性I类（MHC I）分子的相互作用。 最近研究表明，SARS-CoV-2 ORF 8通过下调MHC抑制CD 8 + T细胞反应 I分子，在体外和体内。我们假设ORF 8抑制HLA-A的表面表达， HLA-B分子保护受感染的细胞不被CD 8 + T细胞识别，但不影响HLA-C和HLA-E， 避免激活自然杀伤细胞（NK细胞）。ORF 8对MHCI具有位点特异性的可能性 将为SARS-CoV-2提供一种机制，在适应性免疫和先天免疫之间游走。 具体而言，我们将通过使用一组HLA-1基因，对ORF 8和MHC I之间的相互作用进行分析。 A、-B、-C和-E分子，并且还确定ORF 8是否选择性地下调相关细胞中的MHC I 系统（目标1）。我们将把这些研究扩展到ORF 8变异体，这些变异体在研究过程中被积极选择。 评估这些突变是否以及如何影响MHC I结合和下调 (Aim 2）。这些目标的成功完成有望揭示ORF 8的未知特征， 阐明其在抑制抗原呈递中的作用，并告知我们MHCI 对SARS-CoV-2的影响。我们提出的研究的直接和长期影响是很高的。这是第一 研究：（1）表征ORF 8与宿主蛋白质的分子相互作用;和（2）临床评估 相关的ORF 8变体。通过研究ORF 8介导的免疫相互作用， MHC I，我们将增加我们对SARS-CoV-2如何破坏细胞免疫的理解。重要的是我们的 这项研究将刺激其他ORF 8相互作用者的类似研究，为研究提供新的机会。 开发针对ORF 8或其宿主靶标的治疗剂。