The humoral immune response to glycoprotein B of human cytomegalovirus

人巨细胞病毒（HCMV）是一种普遍分布的病原体，可引起免疫抑制患者和感染新生儿的严重疾病。开发一种疫苗受到高度重视，使用包膜糖蛋白B （gB）作为抗原的临床研究正在进行中。在缺乏HCMV动物模型的情况下，为了设计优化的疫苗，深入了解人类对病毒gB的免疫反应至关重要。从人类记忆B细胞分泌的单克隆抗体（hmab）的全库分析中，我们能够获得gB的抗原图谱。有趣的是，大多数中和的hmab被发现与gB的两个以前未知的抗原结构域结合，将gB上的中和相关位点增加到四个。在拟议的项目中，我们将确定针对这四个位点的hmab的中和机制。此外，我们将建立抗体fab -片段与抗原结构域4 （AD-4）复合物的纯化条件，在自然感染中诱导最高频率的中和hmab，为未来的结构分析奠定基础。总的来说，拟议的项目将更深入地了解人类抗体对这种重要HCMV抗原的反应，并可能确定中和方面的“阿喀琉斯之踵”。

Human cytomegalovirus (HCMV) is a ubiquitously distributed pathogen that causes severe disease in immunosuppressed patients and infected newborns. The development of a vaccine has been given high priority and clinical studies using the envelope glycoprotein B (gB) as antigen are ongoing. In the absence of an animal model for HCMV, it is crucial to develop a thorough understanding of the human immune response against the viral gB in order to design optimized vaccines. From repertoire analysis of monclonal antibodies (hMabs), secreted from human memory B cells, we were able to derive an antigenic map of gB. Interestingly, the majority of neutralizing hMabs were found to bind to two previously unknown antigenic domains of gB, increasing the neutralization relevant sites on gB to four. Within the proposed project we will determine the mechanisms of neutralization of hMabs directed to these four sites. In addition, we will establish conditions for the purification of an antibody Fab-fragment in complex with the antigenic domain 4 (AD-4), which induces the highest frequency of neutralizing hMabs during natural infection, to set the ground for future structural analysis. Overall, the proposed project will provide a deeper understanding of the human antibody response against this important HCMV antigen and may identify an “Achilles heel” with respect to neutralization.