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.

项目概要 登革热病毒 (DENV) 是最重要的节肢动物传播病毒之一，目前导致超过 3.9 亿人死亡 全世界范围内的人类感染登革热病毒可导致儿童和老年人出现严重疾病和死亡。 亚洲和拉丁美洲等地区的 DENV 在基因和血清型上分为四种血清型 (1-4)。 令人震惊的是，在接下来的 50-80 年里，每种血清型都可以进一步细分为不同的基因型。 DENV 感染预计将传播到世界新地区，包括美国，造成数百万人死亡 此外，唯一获得许可的 DENV 疫苗无法发挥作用。 疫苗针对 DENV 血清型 2 (DENV2) 的功效同样出色。 的效率异常低（39%），凸显了改进 DENV 疫苗设计和策略的必要性。 众所周知，DENV 四种血清型之间存在遗传多样性，DENV 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是 因此，该项目旨在定义自然发生的 DENV2 遗传的作用。 中和抗体逃避的变化 该项目还旨在定义 IgG Fc 特征，例如 IgG。 NIH 疫苗中疫苗引发的结合和中和抗体的亚类和 Fcγ 受体结合。 完成这个项目后，我使用反向遗传学生成了 DENV2 基因型变异病毒组。 重要的是，该基因型面板包含来自世界不同地区的当代分离物，包括： 我发现亚洲 I、亚洲 II、亚裔美国人、大都会、森林非洲和森林亚洲分离。 这些 DENV2 基因型变体在 prM 和 E 中表现出相当大的氨基酸残基变异性 结构域 I (EDI)、II (EDII) 和 III (EDIII)，它们是中和抗体的关键靶标。 初步数据表明，DENV2 中观察到的基因型遗传多样性调节差异 对 DENV2- 中和单克隆抗体和多克隆抗体的中和敏感性 因此，我将评估 DENV2 遗传多样性在调节中和作用中的作用。 对来自 NIH 单价 DENV 人类疫苗的疫苗引发的中和抗体产生抗性 此外，我将定义四价 DENV 人类疫苗的 Fc 区特征，例如 IgG 亚类。 并与 Fcγ 受体结合，这些疫苗引发的抗体反应可介导人类保护 DENV 感染的挑战模型 更好地了解 DENV 逃避的机制。 中和抗体对于改善现有表现不佳的 DENV2 疫苗至关重要。 项目结果将提供有关 DENV2 颠覆宿主引发策略的重要信息 中和抗体，这对于合理设计旨在改进疫苗的 DENV 疫苗非常重要 功效。