Structure-based design of an epitope-focused Hepatitis C virus vaccine

基于表位的丙型肝炎病毒疫苗的结构设计

• 批准号: 323016498
• 负责人: Professor Dr. Thomas Krey
• 金额: --
• 依托单位: Institut für Biochemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/323016498?language=en
• 关键词: Structure; based; design; epitope; focused

An estimated 170 million people worldwide are infected with the hepatitis C virus (HCV), and chronic HCV infection is a major cause of liver cirrhosis and liver cancer. The direct-acting antivirals against HCV reach impressive cure rates; however, their high-costs and the emergence of drug-resistant viruses reinforce the urgent need to develop a safe and efficient HCV vaccine. Recent evidence has highlighted the role of neutralizing antibodies (nAbs) in protection from persistent HCV infection. Structural studies of nAb fragments in complex with epitope peptides or HCV glycoprotein E2 have provided the foundation to enable rational vaccine design strategies. The majority of nAbs target the receptor-binding site (CD81) within E2, but the virus has developed a number of mechanisms to evade the neutralizing antibody response that preclude E2 from being an efficient immunogen, such as an extensive glycan shield, immunodominant "decoy" epitopes and a pronounced conformational flexibility. Novel computational design methodologies used for immunogen optimization have paved the way for structure-based vaccine design. These novel approaches allow for the transplantation of specific epitopes to scaffold proteins to focus the antibody response on important neutralization epitopes.The goal of this project is to leverage these novel computational methods to design epitope-focused immunogens that enhance the elicitation of HCV neutralizing antibodies. We will transplant neutralization epitopes from the HCV glycoproteins E1 and E2 (one and four epitopes, respectively), including linear and conformational epitopes as two distinct strategic opportunities. For each of these epitopes, epitope-focused immunogens will be computationally designed and experimentally tested. The most promising candidates will be biophysically, biochemically and structurally characterized; we will subsequently select immunogens with the desired biochemical profile and test their ability to induce a specific antibody response in mice. We will determine the capacity of post-immunization sera to bind E2 and more importantly, assess neutralizing and cross-neutralizing activity. We will investigate the induced antibody responses at the monoclonal level by isolating antigen-specific memory B cells, to characterize the elicited antibodies both structurally and functionally.The proposed project will provide a novel approach for structure-based design of an efficient HCV vaccine. In addition, as structural data on neutralization epitopes within HCV glycoproteins are scarce, co-crystallization of novel immunogens with well-characterized antibody fragments targeting the displayed epitopes will greatly increase our understanding of the interactions between the humoral immune system and the HCV glycoproteins. The strategies developed with this project may also be useful to design optimized immunogens for other infectious diseases that lack efficacious vaccines, such as HIV, Influenza, or malaria.

据估计，全球有1.7亿人感染了丙型肝炎病毒(丙型肝炎病毒)，而慢性丙型肝炎病毒感染是导致肝硬化和肝癌的主要原因。针对丙型肝炎病毒的直接作用的抗病毒药物达到了令人印象深刻的治愈率；然而，它们的高昂成本和耐药病毒的出现加强了开发安全有效的丙型肝炎疫苗的迫切需要。最近的证据强调了中和抗体(NAB)在保护持续的丙型肝炎病毒感染中的作用。NAB片段与抗原表位多肽或丙型肝炎病毒糖蛋白E2的复合体的结构研究为制定合理的疫苗设计策略提供了基础。大多数NAB以E2内的受体结合部位(CD81)为靶点，但病毒已发展出许多机制来逃避中和抗体反应，这些中和抗体使E2无法成为有效的免疫原，例如广泛的糖链保护层、免疫显性的“诱饵”表位和明显的构象灵活性。用于免疫原优化的新的计算设计方法为基于结构的疫苗设计铺平了道路。这些新的方法允许将特定的表位移植到支架蛋白上，以将抗体反应集中在重要的中和表位上。本项目的目标是利用这些新的计算方法来设计专注于表位的免疫原，以增强丙型肝炎病毒中和抗体的激发。我们将移植丙型肝炎病毒糖蛋白E1和E2的中和表位(分别为一个和四个表位)，包括线性表位和构象表位，作为两个不同的战略机遇。对于这些表位中的每一个，都将通过计算设计和实验测试以表位为重点的免疫原。最有希望的候选者将是生物物理、生物化学和结构特征；随后我们将选择具有所需生化特征的免疫原，并测试它们在小鼠中诱导特异性抗体反应的能力。我们将确定免疫后血清结合E2的能力，更重要的是评估中和和交叉中和活性。我们将通过分离抗原特异性记忆B细胞在单抗水平上研究诱导的抗体反应，从结构和功能上表征所激发的抗体，为基于结构的高效丙型肝炎疫苗的设计提供一种新的方法。此外，由于关于丙型肝炎病毒糖蛋白中和表位的结构数据很少，新型免疫原与针对所展示表位的具有良好特征的抗体片段的共结晶将大大增加我们对体液免疫系统与丙型肝炎病毒糖蛋白之间相互作用的了解。与该项目一起开发的战略也可能有助于为其他缺乏有效疫苗的传染病设计优化的免疫原，如艾滋病毒、流感或疟疾。