Probing the antibody response to HCV to facilitate rational immunogen design

描述（由申请人提供）：全球约有1.7亿人感染丙型肝炎病毒（HCV），其中许多人将继续发展为疾病，主要是肝硬化和肝癌。需要一种疫苗来帮助限制疾病的传播。迄今为止开发的大多数有效疫苗可引起中和抗体（nab）。在开发一种诱导抗体对抗HCV的成分的过程中，至少存在两个主要障碍。首先，由于无法在体外培养HCV，缺乏常规的中和试验。这一障碍最近至少部分被HCV培养系统的发展所消除，尽管目前存在一定的局限性。第二个障碍是在受感染的供体中发现的HCV序列差异很大，这表明疫苗应该引发对多种不同病毒有效的nab，即疫苗应该引发广泛中和的抗体。我们提出了一项计划来研究诱导针对多种HCV分离株的强中和抗体反应的必要条件，并利用所获得的知识来设计HCV疫苗的nab诱导成分。我们将系统地分析NAb在自然感染中对HCV的反应，并分离出最有效和广泛的抗多种HCV分离株的单克隆抗体（Aim 1）。这些单克隆抗体原型将帮助我们鉴定HCV上的中和表位，我们将在分子水平上探索这些表位和单克隆抗体之间的相互作用（目的2）。我们将把从这些分子研究中获得的知识应用于免疫原的设计，以便在动物中产生NAb反应（目标3）。原型广泛中和单克隆抗体和来自免疫了新免疫原的动物的单克隆抗体将在小动物模型中进行测试（Aim 4）。公共卫生相关性：丙型肝炎病毒感染是世界范围内的一个主要卫生问题，迫切需要一种疫苗来保护高危人群。我们建议开发针对HCV的抗体诱导候选疫苗。我们工作的一个关键特点是合理设计候选疫苗，以对抗这种病毒用来逃避抗体的一些技巧。

DESCRIPTION (provided by applicant): Approximately 170 million people are infected by hepatitis C virus (HCV) worldwide and many of these will go on to develop disease, primarily cirrhosis of the liver and hepatoma. A vaccine is required to help limit spread of the disease. Most effective vaccines developed to date elicit neutralizing antibodies (NAbs). There have been at least two major roadblocks en route to developing a component that elicits NAbs to HCV. The first is the lack of a conventional neutralization assay because of an inability to culture HCV in vitro. This roadblock has recently been at least partly dismantled by the development of systems for culturing HCV, albeit currently with certain limitations. The second roadblock is the great sequence variation of HCV found in infected donors that suggests a vaccine should elicit NAbs effective against a wide variety of different viruses, i.e. the vaccine should elicit broadly neutralizing antibodies. We propose a program to investigate the necessary conditions to induce a strong neutralizing antibody response against multiple HCV isolates and use the knowledge gained to design a NAb-inducing component of an HCV vaccine. We will systematically dissect NAb responses to HCV in natural infection, and isolate mAbs that are most potent and broad against neutralizing diverse isolates of HCV (Aim 1). These prototype mAbs will help us to identify neutralizing epitopes on HCV and we will explore the interaction between these epitopes and NAbs at the molecular level (Aim 2). We will apply knowledge gained from these molecular studies to the design of immunogens in order to produce NAb responses in animals (Aim 3). The prototype broadly neutralizing mAbs and Abs from animals immunized with the novel immunogens will be tested in a small animal model (Aim 4). PUBLIC HEALTH RELEVANCE: Hepatitis C virus infection is a major health problem worldwide and a vaccine is urgently needed to protect at-risk populations. We propose to develop antibody-inducing vaccine candidates against HCV. A key feature of our work is the rational design of vaccine candidates based on countering some of the tricks that this virus uses to evade antibodies.