Structural and functional basis of ultra potent CHKV neutralization by human mAbs

 描述（由申请方提供）：基孔肯雅病毒（CHIKV）是一种重新出现的蚊媒甲病毒，直接在人类和蚊子之间循环，并在全球范围内引起人类衰弱性发热疾病。新大陆的本土传播现已得到描述，美洲至少有19个国家爆发疫情，仅6个月内就有25万多例病例。截至7月1日，从加勒比海返回美国的29个州的旅行者中已向ArboNET报告了CHIKV疾病病例。由于其主要媒介之一白纹伊蚊的普遍分布，在北美和南美流行的可能性很高。尽管有可能感染并导致数百万人患病，但目前还没有针对CHIKV的特异性治疗或疫苗。该项目的主要目标是定义对所有基因型CHIKV具有广泛活性的超强效中和人mAb的分子、遗传、免疫学和结构特征。其他目标包括定义这些超强效中和mAb的保护机制相关性。在这些研究中，我们将阐明具有特殊抑制活性的抗病毒抗体如何在细胞培养和体内发挥作用。该方法将包括高效分离人单克隆抗体，以及基于下一代测序的创新抗体基因库研究。将测试几种假设，包括以下概念：超强中和活性由抗体（由于持续CHIKV感染引起的广泛突变）和抗原（与多个相邻包膜蛋白上的四级表位结合并阻断对病毒进入或释放至关重要的结构转变）的特征产生。尽管我们的重点是了解超强效人类mAb如何以及为什么抑制CHIKV，但这些研究可能与许多不同病毒的抗体中和的一般原理相关。 除了定义CHIKV的Ab中和的分子和结构基础之外，这些研究将产生一组可以预防和治疗小鼠中的CHIKV感染和持久性的完全人源mAb，其可以在未来开发为用于人类的可能的组合免疫制剂。该项目中的研究虽然针对CHIKV，但可能会为未来针对导致人类疾病的其他甲病毒的基于Ab和/或疫苗的工作提供信息。我们组建了一个独特的研究小组，包括一名人类抗体专家，一名具有抗体-病毒相互作用经验的分子病毒学家，以及两名在甲病毒（包括CHIKV）方面具有特定专业知识的结构生物学家，以进行这些研究。

 DESCRIPTION (provided by applicant): Chikungunya virus (CHIKV) is a re-emerging mosquito-borne alphavirus that cycles directly between humans and mosquitoes and causes a debilitating febrile illness in humans on a global scale. Autochthonous transmission in the New World now has been described, with outbreaks in at least 19 countries in the Americas and over a quarter million cases in just 6 months. CHIKV disease cases have been reported to ArboNET in travelers returning to the US from the Caribbean in 29 states, as of July 1. The potential for epidemics in North and South America is high due to the ubiquitous distribution of one of its primary vectors, Aedes albopictus. Despite the possibility for infecting and causing disease in millions, specific treatments or vaccines for CHIKV are not available. A primary goal of this project is to define the molecular, genetic, immunologic, and structural characteristics of ultra-potent neutralizing human mAbs with broad activity against all genotypes of CHIKV. Additional goals include defining the mechanistic correlates of protection by these ultra-potent neutralizing mAbs. In these studies, we will elucidate how antiviral Abs with exceptional inhibitory activity exert their action in cell culture and in vivo. The approach will include high efficiency isolationof human mAbs, coupled with innovative antibody gene repertoire studies based on nextgen sequencing. Several hypotheses will be tested, including the concept that ultra-potent neutralizing activity results from features of both the antibodies (extensive mutations due to persistent CHIKV infection) and the antigen (binding to quaternary epitopes on multiple adjacent envelope proteins and blocking structural transitions critical for virus entry or release). Althoug our focus is to understand how and why ultra-potent human mAbs inhibit CHIKV, the studies likely will be relevant to general principles of antibody neutralization of many different viruses. Beyond defining the molecular and structural basis of Ab neutralization of CHIKV, these studies will generate a group of fully human mAbs that can prevent and treat CHIKV infection and persistence in mice, which could be developed in the future as a possible combination immunotherapeutic for humans. Studies in this project, while targeted against CHIKV, likely will inform future Ab-based and/or vaccine efforts against other alphaviruses that cause human disease. We have assembled a unique group of investigators, including a human Ab expert, a molecular virologist with experience in Ab-virus interactions, and two accomplished structural biologists with specific expertise in alphaviruses, including CHIKV, to pursue these studies.