Mechanisms of MHCII expression and CD4+ T cell activation during Chlamydia trachomatis infection

沙眼衣原体感染过程中MHCII表达及CD4 T细胞活化机制

• 批准号: 9977431
• 负责人: Andrew Olive
• 金额: $ 19.19万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-17 至 2021-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9977431
• 关键词: Affect; Antigen-Presenting Cells; Antigens; Automobile Driving; CD4 Positive T Lymphocytes; CRISPR screen; CRISPR/Cas technology; Candidate Disease Gene; Cell physiology; Cells; Chimera organism; Chlamydia; Chlamydia Infections; Chlamydia muridarum; Chlamydia trachomatis; Clinical; Clustered Regularly Interspaced Short Palindromic Repeats; Coculture Techniques; Dendritic Cells; Development; Disease; Ectopic Pregnancy; Effectiveness; Environment; Future; Genes; Genetic Transcription; Goals; Immune response; Immunity; Immunologics; Infection; Infection Control; Infertility; Intervention; Invaded; Kinetics; Knock-out; Lead; Major Histocompatibility Complex; Malignant Neoplasms; Mediating; Modeling; Monitor; Mycobacterium tuberculosis; Outcome; Pathology; Pathway interactions; Pelvic Inflammatory Disease; Phenotype; Population; Positioning Attribute; Predisposition; Process; Regulation; Role; Sexually Transmitted Diseases; Signal Transduction; Specificity; Stimulus; Surface; Surface Antigens; T cell response; T-Cell Activation; T-Cell Receptor; T-Lymphocyte; Testing; Trans-Activators; Transgenic Mice; Transgenic Organisms; United States; Validation; Virulence; adaptive immunity; antigen-specific T cells; base; clinically significant; gain of function; genetic approach; genital infection; genome-wide; improved; in vivo; loss of function; macrophage; pathogen; prevent; prophylactic; reproductive tract; response; therapeutic target; tool; trafficking

Project Summary The mammalian host requires CD4+ T cells to survive infections with many distinct intracellular pathogens. Loss of CD4+ T cells leads to susceptibility to infections caused by Chlamydia trachomatis, Mycobacterium tuberculosis and others. Antigen presenting cells (APCs) are at the interface of invading pathogens and adaptive immunity, sensing the infected environment and signaling directly to CD4+ T cells. The expression of Major Histocompatibility Complex II (MHCII) on APCs is critical for CD4+ T cells to detect their cognate antigens and activate an appropriate host response. Many pathogens manipulate the expression of MHCII to evade protective immunity. While complete loss of MHCII prevents CD4+ T cell function, how modulation of MHCII levels during infection impacts the effectiveness of pathogen-specific CD4+ T cell responses remains unknown. We hypothesize that MHCII expression levels are an important factor in the activation and effector function of antigen-specific CD4+ T cells. By understanding how MHCII is regulated at a global scale we will be positioned to develop interventions that modulate MHCII expression in order to overcome pathogen virulence strategies aimed at blunting protective host responses. We performed a genome-wide CRISPR-Cas9 screen to identify regulators of MHCII surface expression in activated APCs. We found over 200 genes that significantly alter surface MHCII expression with no described function in MHCII regulation. Here, using CRISPR-Cas9 mediated gain-of-function and loss-of-function approaches we will systemically identify priority candidates that enhance or inhibit MHCII surface expression and begin to dissect their mechanisms of MHCII control. We will next determine how modulation of MHCII expression directly alters the pathogen-specific CD4+ T cell response during genital infections with Chlamydia muridarum. We are investigating Chlamydia because it is an important pathogen clinically as the number one bacterial sexually transmitted infection in the United States. Chlamydia causes severe pathologies that lead to infertility, ectopic pregnancy and pelvic inflammatory disease. We will track the Chlamydia-specific CD4+ T cell response using immunological tools that do not exist for most pathogens. In combination with our CRISPR approaches we are uniquely positioned to directly examine how MHCII expression impacts the Chlamydia-specific CD4+ T cell response ex vivo and in vivo. We will determine how enhanced or reduced MHCII expression on APCs alters a range of CD4+ T cell phenotypes including activation, proliferation, effector function, protection and the development of genital tract pathologies. Our focused studies on the role of MHCII expression during C. trachomatis infection will broadly identify regulators of MHCII that can then be explored in a range of disease states where CD4+ T cell activation is required and MHCII is manipulated including other intracellular pathogens or cancers.

项目摘要 哺乳动物宿主需要CD4 + T细胞才能在许多不同的细胞内病原体感染下存活。 CD4 + T细胞的缺失导致对沙眼衣原体、分枝杆菌 肺结核和其他。抗原呈递细胞（APC）位于入侵病原体的界面， 获得性免疫，感知感染环境并直接向CD4 + T细胞发出信号。的表达 APC上的主要组织相容性复合物II（MHCII）对于CD4 + T细胞检测其同源物至关重要。 抗原并激活适当的宿主反应。许多病原体操纵MHCII的表达， 逃避保护性豁免虽然MHCII的完全丧失阻止了CD4 + T细胞功能，但如何调节MHCII的表达？ 感染期间MHCII水平影响病原体特异性CD4 + T细胞应答的有效性 未知我们假设MHCII表达水平是激活和效应细胞的重要因素。 抗原特异性CD4 + T细胞的功能。通过了解MHCII在全球范围内的监管方式， 能够开发调节MHCII表达的干预措施，以克服病原体毒力 旨在减弱保护性宿主反应的策略。我们进行了全基因组CRISPR-Cas9筛选， 鉴定活化APC中MHCII表面表达调节剂。我们发现了超过200个基因 改变表面MHCII表达，在MHCII调节中没有描述的功能。在这里，使用CRISPR-Cas9 介导的功能获得和功能丧失方法，我们将系统地确定优先候选者， 增强或抑制MHCII表面表达，并开始剖析其MHCII控制机制。我们将 接下来确定MHCII表达的调节如何直接改变病原体特异性CD4 + T细胞应答 在生殖器感染衣原体的时候我们正在调查衣原体，因为它是一个重要的 病原体临床上作为头号细菌性性传播感染在美国。衣原体 导致严重的病理，导致不孕不育，宫外孕和盆腔炎。我们将 使用免疫学工具跟踪衣原体特异性CD4 + T细胞反应，这些工具对大多数人来说并不存在。 病原体结合我们的CRISPR方法，我们处于独特的地位，可以直接研究如何 MHCII表达影响体外和体内衣原体特异性CD4 + T细胞应答。我们将确定 APC上MHCII表达的增强或减少如何改变一系列CD4 + T细胞表型，包括 活化、增殖、效应子功能、保护和生殖道病变的发展。我们 重点研究了MHCII表达在C.沙眼感染将广泛识别监管机构 然后可以在需要CD4 + T细胞活化的一系列疾病状态中探索MHCII， 操纵MHCII，包括其他细胞内病原体或癌症。