MHCII Cross-presentation as a Driver of CD4+ T Cell Responses to Poxviruses

MHCII 交叉呈递作为 CD4 T 细胞对痘病毒反应的驱动因素

基本信息

批准号：
9198974
负责人：
Laurence Crane Eisenlohr
金额：
$ 56.46万
依托单位：
CHILDREN'S HOSP OF PHILADELPHIA
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-07-15 至 2019-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9198974
关键词：
Achievement Adoptive Transfer Anabolism Antigen Presentation Pathway Antigen-Presenting Cells Antigens Area Autoimmune Diseases Binding Bioinformatics Biological Assay Biology CD4 Positive T Lymphocytes Catalysis Cell membrane Cell physiology Cells Clinical Complex Cross Presentation Data Dendritic Cells Development DsRed Ectromelia Epitopes Eukaryota Goals Histocompatibility Antigens Class II Host Defense Human Hybridomas Image Immune system In Vitro Infectious Ectromelia Influenza Investigation Knock-out Lead Location MHC Class I Genes MHC Class II Genes Mediating Mediator of activation protein Modeling Mus Pathogenesis Pathway interactions Peptide Library Peptide/MHC Complex Peptides Play Poxviridae Process Proteins Reagent Reporting Research Resistance Role Scheme Series Smallpox Vaccine Source Specificity Structure Surface Testing Therapeutic Vaccine Design Vaccinia Viral Viral Antigens Viral Proteins Virion Virulence Virus Work anti-influenza experimental study extracellular flu gene product immunoregulation in vivo insight late endosome novel novel strategies pathogen protein aminoacid sequence public health relevance response symposium

项目摘要

DESCRIPTION (provided by applicant): By recognizing foreign peptides (epitopes) in combination with Major Histocompatibility Complex class II molecules (MHCII), CD4+ T lymphocytes (TCD4+) play a critical role in the adaptive responses to most viruses, including the poxviruses, which continue to pose a considerable threat to humans worldwide. According to a convention developed with nominal protein antigens, MHCII-bound peptides are derived from internalized material that is catabolized in the endocytic network and loaded onto nascent MHCII in the late endosome, the complex subsequently transiting to the plasma membrane. Previous and ongoing work in the Eisenlohr lab has demonstrated that this classical scheme contributes minimally to the activation of influenza (flu)-specific TCD4+. Catalysis of whole virions is inefficient and, instead, viral proteins synthesized within the infected antigen- presenting cell (APC) are the primary source of peptides, generated via a network of endogenous processing pathways and directly presented to flu-specific TCD4+. We have recently extended the work to poxviruses in order to explore the generality of these findings. Investigation of vaccinia (VACV) and ectromelia (ECTV) reveals the landscape to be far more complex. As with flu, exogenously provided poxvirions are also resistant to processing, necessitating biosynthesis of viral proteins. However, in contrast to flu, TCD4+ activation appears to depend primarily upon MHCII cross-presentation, in which the biosynthesized antigen is transferred from an infected cell to an uninfected APC. This is attributable to profound inhibition of direct presentation by the infected cell, particularly in the case of ECTV, a natural mouse pathogen. While direct disruption of MHC class I-restricted antigen processing and presentation is well known, it has rarely been reported for MHCII, and the degree and specificity of inhibition by poxviruses is unprecedented. Established work by the Roper lab has identified the A35 gene product of both VACV and ECTV as a major mediator of the inhibition, and preliminary data from the Hersperger lab implicates the B22 gene product as a potent co-conspirator. This Co-PI RO1 application, which combines expertise in antigen processing and presentation with that in poxvirus biology and pathogenesis, will extend these preliminary findings as follows: 1) Rigorously test the hypothesis both in vitro (Aim 1) and in vivo (Aim 2) that MHCII cross-presentation is the principal driver of TCD4+ responses to VACV- and ECTV-specific TCD4+ responses, 2) Determine the contributions of A35 and B22 to the block in direct presentation and identify other poxviral products that might provide complementary activity (Aim 3). 3) Identify the mechanisms underlying A35 and B22 inhibitory activities (Aim 4). These studies bring together three areas of high impact - TCD4+ recognition of viral antigens, poxvirus virulence, and viral subversion of MHCII antigen processing and presentation. Achievement of the aims will substantially enhance understanding of poxvirus pathogenesis and rational vaccine design, and could lead to novel experimental and clinical immunomodulatory strategies.

描述（由申请人提供）：通过识别外源肽（表位）与主要组织相容性复合物 II 类分子 (MHCII) 的组合，CD4+ T 淋巴细胞 (TCD4+) 在对大多数病毒（包括痘病毒）的适应性反应中发挥着关键作用，根据名义蛋白抗原制定的惯例，MHCII 结合肽源自在体内分解代谢的内化物质。 Eisenlohr 实验室先前和正在进行的工作表明，这种经典方案对流感 (flu) 特异性 TCD4+ 催化的激活作用微乎其微。完整病毒体的合成效率低下，相反，在受感染的抗原呈递细胞（APC）内合成的病毒蛋白是肽的主要来源，通过内源性加工途径网络产生并直接呈递给我们最近将研究扩展到痘病毒，以探索这些发现的普遍性，对痘苗病毒 (VACV) 和痘病毒 (ECTV) 的研究表明，与流感一样，外源提供的痘病毒粒子要复杂得多。也对加工有抵抗力，需要病毒蛋白的生物合成。然而，与流感相比，TCD4+ 激活似乎主要取决于 MHCII 交叉呈递，其中生物合成的抗原从受感染的细胞转移到未受感染的 APC，这归因于深刻的原因。抑制受感染细胞的直接呈递，特别是在 ECTV 的情况下，ECTV 是一种天然的虽然直接破坏 MHC I 类限制性抗原的加工和呈递是众所周知的，但很少有关于 MHCII 的报道，而痘病毒的抑制程度和特异性是前所未有的，Roper 实验室已确定 A35。 VACV 和 ECTV 的基因产物是抑制的主要介质，Hersperger 实验室的初步数据表明 B22 基因产物是该 Co-PI 的一个有效的共谋者。 RO1 应用结合了抗原加工和呈递方面的专业知识以及痘病毒生物学和发病机制方面的专业知识，将扩展这些初步发现如下： 1) 在体外（目标 1）和体内（目标 2）严格测试 MHCII 交叉的假设-呈现是 TCD4+ 对 VACV 和 ECTV 特定 TCD4+ 响应的主要驱动力，2) 确定 A35 和 B22 对直接呈现中的块的贡献，并确定其他可能提供互补活性的痘病毒产品（目标 3）确定 A35 和 B22 抑制活性的机制（目标 4）。这些研究汇集了三个具有高影响力的领域 - TCD4+ 识别病毒抗原、痘病毒毒力和病毒颠覆。 MHCII 抗原加工和呈递的目标的实现将大大增强对痘病毒发病机制和合理疫苗设计的理解，并可能导致新的实验和临床免疫调节策略。