Protective B-cell responses in chikungunya virus infection

 描述(由申请人提供)：基孔肯雅病毒(CHIKV)如果被引入美国，可能会造成重大的公共卫生影响，这似乎是在加勒比海爆发大规模和持续疫情之后发生的。CHIKV造成广泛的人类和经济损失，主要是由于急性发烧和关节痛以及病毒感染后的慢性关节疼痛/关节炎。目前尚无获得许可的CHIKV治疗方法或疫苗。我们将通过确定主要候选单抗(MAbb)来应对CHIKV构成的重要公共卫生威胁，以开发出能够用于预防和治疗的治疗方法。重要的是，我们已经证明了针对CHIKV的单抗能够阻止病毒的组装/萌发--可能是通过防止形成颗粒所需的包膜糖蛋白驱动的膜弯曲来实现的。我们将描述针对这一机制的新抗体的特征，以及描述在急性感染患者和康复患者中对感染做出反应的完整B细胞谱系。最后，我们将描述CHIKV的遗传多样性和进化，重点是检测B细胞表位的变异和选择特征。为了实现这些目标，我们将实现三个具体目标：目标1.鉴定和鉴定能够抑制萌发的有效人类单克隆。我们将从CHIKV康复患者中提取并筛选出专门用于抑制CHIKV病毒释放/萌发的B细胞克隆。由此产生的单抗将被鉴定为在体外和体内的效力，其表位将使用逃逸突变和突变来绘制。目的2.研究CHIKV感染后的急性和记忆性B细胞反应。利用免疫谱系捕获(IRC)技术，我们将全面绘制CHIKV感染期间的B细胞谱系。将通过在多个个体中寻找B细胞副表位的趋同进化来识别共同表位，并将在急性感染和康复个体中表征进入中和和萌发抑制之间的关系。目的3.CHIKV囊膜糖蛋白的多样性和进化特征。为了评估AIMS 1和AIMS 2中衍生的抗体具有广泛交叉反应的可能性，我们将表征CHIKV包膜序列变异的性质和程度，这些病毒分离株来自参与研究的个人(超过三年)以及来自更广泛的全球人群的CHIKV序列。将对数据集进行筛选，以寻找选择性压力的特征，特别是来自体液反应的特征。综上所述，我们希望开发针对病毒生命周期特定阶段的新型单抗。感染期间的体液反应将被绘制成地图，并与病毒多样性和进化相关。

 DESCRIPTION (provided by applicant): Chikungunya virus (CHIKV) has the potential to create a major public health impact should it be introduced into the United States, as seems likely following a large and sustained outbreak in the Caribbean. CHIKV causes extensive human and economic damage, primarily due to acute fever and arthralgia and post-viral chronic joint pain/arthritis. Currently no licensed therapeutic treatments or vaccines exist for CHIKV. We will address the important public health threat posed by CHIKV by identifying lead candidate monoclonal antibodies (mAbs) for development into treatments capable of being used both prophylactically and therapeutically. Importantly, we have demonstrated the ability of mAbs directed against CHIKV to block viral assembly/budding - probably by preventing the envelope glycoprotein-driven membrane curvature required to form particles. We will characterize new antibodies targeting this mechanism, as well as describe the full B-cell repertoire in response to infection - both in acutely infected patients and recovered individuals. Finally, we will characterize CHIKV genetic diversity and evolution with emphasis on detecting variation and signatures of selection at B-cell epitopes. In order to achieve these goals we will perform three Specific Aims: Aim 1. Identification and characterization of potent human monoclonals capable of budding inhibition. We will derive and screen B-cell clones from recovered CHIKV patients specifically for inhibition of CHIKV virus release/budding. Resulting mAbs will be characterized for in vitro and in vivo potency, and their epitopes will be mapped using escape mutants and mutagenesis. Aim 2. Characterize acute and memory B-cell responses to CHIKV infection. Using immune repertoire capture (IRC) technology, we will fully map B-cell repertoires during CHIKV infection. Common epitopes will be identified by looking for convergent evolution of B-cell paratopes in multiple individuals, and the relationship between entry neutralization and budding inhibition will be characterized in acutely infected and recovered individuals. Aim 3. Characterization of CHIKV envelope glycoprotein diversity and evolution. In order to assess the potential for the antibodies derived in Aims 1 and 2 to be broadly cross reactive, we will characterize the nature and extent of CHIKV envelope sequence variation in viral isolates derived from individuals enrolled in the study (over three years) together with CHIKV sequences from the wider global population. Data sets will be screened for signatures of selective pressure, particularly from the humoral response. In summary, we hope to develop novel mAbs, targeting specific stages of the viral lifecycle. The humoral responses during infection will be mapped and related to viral diversity and evolution.