The humoral immune response to glycoprotein B of human cytomegalovirus

人巨细胞病毒(HCMV)是一种广泛分布的病原体，在免疫抑制患者和感染的新生儿中可引起严重疾病。疫苗的开发已经得到高度重视，使用包膜糖蛋白B(GB)作为抗原的临床研究正在进行中。在缺乏人巨细胞病毒的动物模型的情况下，为了设计优化的疫苗，彻底了解人类对gB病毒的免疫反应是至关重要的。通过对人类记忆B细胞分泌的单抗(HMabs)的谱系分析，我们得到了GB的抗原图。有趣的是，大多数中和的hMab被发现与GB的两个先前未知的抗原域结合，使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地点的hMAbs的中和机制。此外，我们还将建立纯化抗原区4(AD-4)的抗体Fab片段的条件，为未来的结构分析奠定基础。AD-4在自然感染期间诱导中和hMabs的频率最高。总体而言，拟议的项目将提供对人类对这一重要的HCMV抗原的抗体反应的更深层次的了解，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.