Defining viral and immune mechanisms of Dengue virus serotype 2 immune evasion

定义登革热病毒血清型 2 免疫逃避的病毒和免疫机制

• 批准号: 10066591
• 负责人: David R. Martinez
• 金额: $ 4.12万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2021-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10066591
• 关键词: Affect; African; Amino Acid Sequence; Amino Acids; Antibodies; Antibody Response; Antibody-mediated protection; Arboviruses; Area; Asia; Asian Americans; Asians; Binding; Biological Assay; Cells; Cessation of life; Characteristics; Child; Chimera organism; Clinical; Complex; Data; Dengue; Dengue Infection; Dengue Vaccine; Dengue Virus; Development; Disease; E protein; Elderly; Enzyme-Linked Immunosorbent Assay; Epitopes; Exhibits; Failure; Fc Receptor; Flow Cytometry; Genetic; Genetic Variation; Genotype; Goals; Human; Immune; Immune Evasion; Immunity; Immunoglobulin G; Individual; Infection; Knowledge; Latin America; Maps; Measures; Mediating; Membrane; Modeling; Monoclonal Antibodies; Patients; Phenotype; Proteins; Recombinants; Resistance; Risk; Role; Sampling; Serological; Serotyping; Serum; Structural Protein; Techniques; Transmission Electron Microscopy; U937 Cells; United States; United States Food and Drug Administration; United States National Institutes of Health; Vaccine Design; Vaccines; Variant; Viral; Virion; Virus; Virus Diseases; Western Blotting; World Health Organization; design; improved; monocyte; neutralizing antibody; neutralizing monoclonal antibodies; novel strategies; polyclonal antibody; receptor; receptor binding; receptor vaccine; response; reverse genetics; seropositive; success; vaccine development; vaccine efficacy; virology

Project summary Dengue virus (DENV) is one of the most significant arthropod-borne viruses currently leading to >390 million human infections worldwide. DENV can cause severe disease and death in children and the elderly in endemic regions such as Asia and Latin America. DENV is genetically and serotypically divided into four serotypes (1-4) and each serotype can be further subdivided into distinct genotypes. Alarmingly, in the next 50-80 years, DENV infections are projected to spread to new areas of the world, including the United States, putting millions of additional individuals at risk for DENV disease. Moreover, the only licensed DENV vaccine does not perform equally well against the existing four DENV serotypes. The vaccine efficacy against DENV serotype 2 (DENV2) is remarkably low (39% efficacy), underlining the need to improve DENV vaccine design and strategies. While it is known that DENV genetic diversity exists among the four serotypes, the role of DENV intraserotypic diversity within the distinct genotypes in modulating neutralization resistance to vaccine-elicited antibodies is not well understood. Therefore, this project aims to define the role of naturally occurring DENV2 genetic variation on neutralizing antibody evasion. This project also aims to define IgG Fc characteristics, such as IgG subclass and Fcγ receptor binding, of vaccine-elicited binding and neutralizing antibodies in NIH vaccinees. To complete this project, I have generated a DENV2 genotype variant virus panel using reverse genetics. Importantly, this genotype panel contains contemporary isolates from distinct regions in the world including: Asian I, Asian II, Asian-American, Cosmopolitan, Sylvatic African, and Sylvatic Asian isolates. I discovered that these DENV2 genotypic variants exhibit considerable amino acid residue variability within the prM and in E domain I (EDI), II (EDII), and III (EDIII), which are key targets for neutralizing antibodies. Interestingly, my preliminary data demonstrates that the genotypic genetic diversity observed in DENV2 modulates differential neutralization sensitivity to both neutralizing monoclonal antibodies and polyclonal antibodies from DENV2- infected individuals. I will therefore evaluate the role of DENV2 genetic diversity in modulating neutralization resistance to vaccine-elicited neutralizing antibodies from NIH monovalent DENV human vaccinees and tetravalent DENV human vaccinees. Moreover, I will define the Fc region characteristics, such as IgG subclass and binding to Fcγ receptors, of these vaccine-elicited antibody responses that mediate protection in a human challenge model of DENV infection. A better understanding of the mechanism(s) by which DENV evades neutralizing antibodies will be critical to improve the existing DENV2 vaccine that performs poorly. These project findings will provide crucial information on the strategies that DENV2 employs to subvert host-elicited neutralizing antibodies, which will be important to rationally design DENV vaccines aimed at improving vaccine efficacy.

项目摘要 登革病毒（DENV）是最重要的节肢动物传播病毒之一，目前导致超过3.9亿人感染 全球范围内的人类感染。登革病毒可引起严重的疾病和死亡的儿童和老年人在地方性 亚洲和拉丁美洲等地区。DENV在遗传和血清型上分为四种血清型（1-4） 并且每种血清型可以进一步细分为不同的基因型。令人担忧的是，在未来50-80年， DENV感染预计将蔓延到世界新的地区，包括美国，使数百万人 有感染登革病毒风险的人。此外，唯一获得许可的DENV疫苗不执行 针对现有的四种DENV血清型同样良好。针对DENV血清型2（DENV 2）的疫苗效力 这一结果表明，DENV疫苗的有效性非常低（39%的有效性），强调需要改进DENV疫苗的设计和策略。而 已知DENV的遗传多样性存在于四种血清型之间，DENV在血清型内的作用 不同基因型在调节对疫苗引起的抗体的中和抗性方面的多样性， 没有很好地理解。因此，该项目旨在确定自然发生的DENV 2遗传的作用， 中和抗体逃避的变异。该项目还旨在定义IgG Fc特性，例如IgG NIH疫苗接种者中疫苗引发的结合和中和抗体的亚类和Fcγ受体结合。到 完成这个项目后，我已经使用反向遗传学生成了DENV 2基因型变异病毒面板。 重要的是，该基因型组包含来自世界不同地区的当代分离株，包括： 亚洲I型、亚洲II型、亚裔美国人、世界性、森林型非洲和森林型亚洲分离株。我发现 这些DENV 2基因型变体在prM内和E 结构域I（EDI）、II（EDII）和III（EDIII），它们是中和抗体的关键靶标。有趣的是，我的 初步数据表明，在DENV 2中观察到的基因型遗传多样性调节了差异表达。 对来自DENV 2的中和性单克隆抗体和多克隆抗体的中和敏感性- 感染的人。因此，我将评估DENV 2遗传多样性在调节中和中的作用 - 对来自NIH单价DENV人疫苗的疫苗引发的中和抗体的抗性， 四价DENV人疫苗。此外，我将定义Fc区的特征，如IgG亚类 和Fcγ受体结合，这些疫苗引起的抗体应答介导了人体免疫保护作用。 DENV感染的攻击模型。更好地理解DENV逃避的机制 中和抗体对于改善现有的表现不佳的DENV 2疫苗至关重要。这些 该项目的研究结果将提供有关DENV 2用于破坏宿主诱导的策略的关键信息。 中和抗体，这将是重要的合理设计登革病毒疫苗，旨在提高疫苗 功效