Immunization strategies to elicit broadly neutralizing antibodies against HCV

项目摘要 丙型肝炎病毒（HCV）感染全世界超过7000万人，是慢性肝硬化的主要原因 和肝癌。尽管直接作用的抗病毒药物取得了成功，但控制HCV流行仍然具有挑战性 由于早期病毒检测困难、治疗成本高以及成功后可能再次感染 治疗一种有效的预防性疫苗将有助于控制这种流行病，但巨大的遗传 HCV的多样性阻碍了其发展。尽管病毒的变异性很高，但30%的HCV感染者 个体通过产生广泛中和抗体（bNAbs）来清除病毒感染， HCV糖蛋白E2的中和表位。通过疫苗接种刺激bNAb的产生，HCV 流行病可能会停止。 最近，我们从不同的HCV分离株中鉴定出几种E2蛋白，它们与人类生殖系前体细胞结合， bNAbs，提高了使用这些变体开发疫苗的可能性。在本提案中，我们的目标是使用 天然存在的E2蛋白来设计将在动物中引发HCV特异性bNAb的免疫原 模型为了实现这一目标，将在野生型中测试基于E2蛋白或病毒样颗粒的免疫原。 小鼠和非人类灵长类动物。接下来，将对免疫诱导的HCV特异性抗体的结构进行分析。 测定为此，我们将对来自接种疫苗的动物的表位特异性B细胞进行分选和测序，并表达 这些序列的抗体。然后，我们将确定单独或联合HCV特异性bNAb的结构。 与免疫原的复合物，以阐明疫苗诱导的HCV广泛中和的决定因素 抗体的对所引发的抗体应答的详细分析将有助于优化免疫原 通过增强它们的特异性和选择性。总之，这些目标的结果将导致确定和 表征新的疫苗候选物，引发HCV特异性bNAb，促进开发一种新的疫苗。 有效的HCV疫苗。 该计划的指导阶段将在加州理工学院的Pamela Bjorkman博士的实验室进行。由于 是几个关键领域的拟议项目，需要额外的培训，博士安德鲁Flyak已经组装 一个由结构生物学（Pamela Bjorkman博士）、B细胞免疫学（Dr. Michel Nussenzweig）和HCV生物学（Justin Bailey博士）。通过使用跨学科的方法， 在整个项目中，在指导委员会的支持下，Flyak博士将开始独立阶段 该奖项，回答了阻碍开发有效的HCV疫苗的基本问题， 或其他快速变异的病毒。 !

PROJECT SUMMARY Hepatitis C virus (HCV) infects over 70 million people worldwide and is a leading cause of chronic liver cirrhosis and liver cancer. Despite the success of direct-acting antivirals, control of the HCV epidemic remains challenging due to difficulties in early virus detection, the high cost of therapy, and possible reinfection after the successful treatment. An effective prophylactic vaccine would help to control the epidemic, but the enormous genetic diversity of the HCV hampers its development. Despite the high variability of the virus, 30% of HCV-infected individuals clear the viral infection by developing broadly neutralizing antibodies (bNAbs) that bind to conserved neutralizing epitopes of HCV glycoprotein E2. By stimulating the development of bNAbs by vaccination, the HCV epidemic might be stopped. We recently identified several E2 proteins from different HCV isolates that bind to germline precursors of human bNAbs, raising the possibility of vaccine development using these variants. In this proposal, we aim to use naturally-occurring E2 proteins to design immunogens that will elicit HCV-specific bNAbs in animal models. To accomplish this goal, E2 protein or virus-like particle-based immunogens will be tested in wild-type mice and non-human primates. Next, the structures of HCV-specific antibodies induced by immunization will be determined. For this, we will sort and sequence epitope-specific B cells from vaccinated animals and express antibodies from these sequences. Then, we will determine the structures of HCV-specific bNAbs alone or in complex with immunogens to elucidate the determinants of broad neutralization of HCV by vaccine-induced antibodies. The detailed analysis of the elicited antibody response will facilitate the optimization of immunogens by enhancing their specificity and selectivity. Together, the results of these aims will lead to the identification and characterization of novel vaccine candidates that elicit HCV-specific bNAbs, facilitating the development of an effective HCV vaccine. The mentoring phase of this proposal will take place in Dr. Pamela Bjorkman's laboratory at Caltech. Since there are several critical areas of the proposed project that require additional training, Dr. Andrew Flyak has assembled a mentorship committee comprising experts in structural biology (Dr. Pamela Bjorkman), B cell immunology (Dr. Michel Nussenzweig), and HCV biology (Dr. Justin Bailey). By using an interdisciplinary approach developed throughout this project and support from the mentoring committee, Dr. Flyak will begin the independent phase of this award, answering fundamental questions that hinder the development of effective vaccines against HCV, or other rapidly mutating viruses. !