Genetic Modifiers of Immune Evasion by Cytomegalovirus in Glioblastoma

胶质母细胞瘤中巨细胞病毒免疫逃避的基因修饰

• 批准号: 8374071
• 负责人: JANARDAN P PANDEY
• 金额: $ 22.13万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8374071
• 关键词: Affect; Affinity; Affinity Chromatography; Alleles; Antibodies; Antibody Formation; Attention; Binding; CMV glycoprotein B; Candidate Disease Gene; Cells; Chromosomes, Human, Pair 14; Complement; Complex; Consensus; Cytomegalovirus; DNA; Diagnosis; Diagnostic Neoplasm Staging; Disease; Disease Progression; Environment; Environmental Risk Factor; Enzyme-Linked Immunosorbent Assay; Etiology; Fc domain; Frequencies; Genes; Genetic; Genotype; Glioblastoma; Glioma; Gliomagenesis; Herpesviridae; IgG1; Immune; Immune response; Immune system; Immunity; Immunocompetence; Immunoglobulin G; Immunologic Monitoring; Immunotherapeutic agent; Immunotherapy; Investigation; Laboratories; Lead; Malignant Glioma; Malignant Neoplasms; Malignant neoplasm of brain; Mediating; Methods; Molecular; Monitor; Neoplastic Processes; Pathogenesis; Patients; Phagocytosis; Plasma; Population; Predisposition; Prevalence; Property; Protein Binding; Proteins; Risk; Role; Series; Seroprevalences; Serum; Surface Plasmon Resonance; Testing; Tumor Promoters; Tumor stage; Viral; Virus; antibody-dependent cell cytotoxicity; brain cell; comparative; genome-wide; killings; novel; promoter; receptor; research study; tumorigenesis

DESCRIPTION (provided by applicant): Increasing evidence implicates human cytomegalovirus (HCMV) in the etiology of glioblastoma (GBM): HCMV proteins have been implicated as tumor promoters in gliomagenesis; glioma grade-as well as patient survival-directly correlates with the level of HCMV gene products. In this proposal, we seek to understand why this common herpesvirus causes disease in only a subset of those infected: HCMV seroprevalence, 80% vs. the prevalence of GBM, 0.025%. HCMV has evolved highly sophisticated immune evasion strategies. One strategy involves generating two proteins-encoded by genes TRL11/IRL11 and UL119-UL118-that have functional properties of the Fc?R, which may enable the virus to evade host immunosurveillance by evading the effector consequences of antibody binding, such as ADCC. Recent studies from our laboratory show that alleles of a major gene complex of the immune system-GM allotypes encoded by three highly polymorphic IGHG loci on chromosome 14-modulate this viral strategy: The HCMV TRL11/IRL11-encoded Fc?R has significantly higher affinity for IgG1 proteins expressing the GM 3+,1-,2- allotypes than for those expressing the allelic GM 17+,1+,2+ allotypes (p = 0.0005). These observations led us to hypothesize that GM genes are effect modifiers of HCMV-GBM association and the underlying mechanisms include their contribution to anti-HCMV antibody responses and their modulating influence on the viral immune-evasion strategies. The following specific aims will test our hypothesis: 1) Determine if the distribution of GM determinants in GBM patients is different from that in controls. DNA from GBM patients and controls will be genotyped for several GM alleles. Because of their higher affinity to the HCMV-encoded Fc?R, anti-HCMV IgG1 antibodies expressing the GM 3+,1-,2- allotypes would be more likely to have their Fc domains scavenged, thereby reducing their immunological competence to eliminate the virus through ADCC and other Fc-mediated effector mechanisms. Consequently, the frequency of these allotypes would be expected to be higher in patients than in controls; 2) Compare the levels of anti-HCMV antibodies in GBM patients and in controls, and determine if they are associated with particular GM alleles. Antibodies to HCMV glycoprotein B (gB) in the sera/plasma of patients and controls will be quantitated by an ELISA and the levels will be compared between the two groups. We will also determine whether the antibody levels are associated with particular GM alleles; 3) Determine if HCMV-encoded Fc?R proteins bind differentially with genetically disparate Fc (GM) regions of anti-HCMV IgG antibodies in GBM patients. Ectodomains of HCMV-encoded Fc?Rs will be cloned and expressed. We will purify IgG antibodies directed against HCMV gB from the sera of GBM patients. Binding and comparative affinities of IgG molecules of different GM allotypes to the HCMV Fc?Rs will be monitored by surface plasmon resonance. Results from the proposed investigation are likely to open a new avenue of investigation in a malignancy that kills approximately 13000 people every year in the U.S. alone. PUBLIC HEALTH RELEVANCE: Glioblastoma is a highly lethal brain cancer. Cytomegalovirus, a common herpesvirus, has been implicated in the etiology of this malignancy. This project investigates the role of a major gene of the immune system in the etiopathogenesis of cytomegalovirus-spurred glioblastoma. Results from these investigations could help devise novel immunotherapeutic strategies against this cancer.

描述（由申请人提供）：越来越多的证据表明人巨细胞病毒（HCMV）与胶质母细胞瘤（GBM）的病因有关：HCMV 蛋白已被认为是胶质瘤发生中的肿瘤促进剂；神经胶质瘤的分级以及患者的生存率与 HCMV 基因产物的水平直接相关。在本提案中，我们试图了解为什么这种常见的疱疹病毒仅在一部分感染者中引起疾病​​：HCMV 血清流行率为 80%，而 GBM 流行率为 0.025%。 HCMV 已进化出高度复杂的免疫逃避策略。一种策略涉及生成两种由 TRL11/IRL11 和 UL119-UL118 基因编码的蛋白质，它们具有 Fc?R 的功能特性，这可能使病毒能够通过逃避抗体结合的效应后果（例如 ADCC）来逃避宿主免疫监视。我们实验室的最新研究表明，免疫系统主要基因复合体的等位基因 - 由 14 号染色体上三个高度多态性 IGHG 位点编码的 GM 同种异型 - 调节这种病毒策略：HCMV TRL11/IRL11 编码的 Fc?R 对表达 GM 3+,1-,2- 同种异型的 IgG1 蛋白的亲和力明显高于表达等位基因的 IgG1 蛋白 GM 17+,1+,2+ 同种异型 (p = 0.0005)。这些观察结果使我们推测 GM 基因是 HCMV-GBM 关联的效应调节剂，其潜在机制包括它们对抗 HCMV 抗体反应的贡献以及它们对病毒免疫逃避策略的调节影响。以下具体目标将检验我们的假设：1）确定 GBM 患者中 GM 决定因素的分布是否与对照组不同。 GBM 患者和对照者的 DNA 将对多个 GM 等位基因进行基因分型。由于其与 HCMV 编码的 Fc?R 的亲和力较高，表达 GM 3+,1-,2- 同种异型的抗 HCMV IgG1 抗体更有可能清除其 Fc 结构域，从而降低其通过 ADCC 和其他 Fc 介导的效应机制消除病毒的免疫能力。因此，这些同种异型在患者中的出现频率预计会高于对照组； 2) 比较 GBM 患者和对照组的抗 HCMV 抗体水平，并确定它们是否与特定 GM 等位基因相关。将通过 ELISA 定量患者和对照血清/血浆中的 HCMV 糖蛋白 B (gB) 抗体，并比较两组之间的水平。我们还将确定抗体水平是否与特定的 GM 等位基因相关； 3) 确定 HCMV 编码的 Fc?R 蛋白是否与 GBM 患者中抗 HCMV IgG 抗体的遗传上不同的 Fc (GM) 区域有差异地结合。 HCMV 编码的 Fc?R 的胞外域将被克隆和表达。我们将从 GBM 患者的血清中纯化针对 HCMV gB 的 IgG 抗体。不同GM同种异型的IgG分子与HCMV FcγR的结合和比较亲和力将通过表面等离子体共振来监测。拟议的调查结果可能会为这种恶性肿瘤的调查开辟一条新途径，仅在美国每年就导致约 13000 人死亡。 公共卫生相关性：胶质母细胞瘤是一种高度致命的脑癌。巨细胞病毒是一种常见的疱疹病毒，与这种恶性肿瘤的病因有关。该项目研究免疫系统的主要基因在巨细胞病毒刺激的胶质母细胞瘤发病机制中的作用。这些研究的结果可以帮助设计针对这种癌症的新型免疫治疗策略。