Project 2

项目摘要-项目2（PD：Pamela Bjorkman） 寨卡病毒（ZIKV）感染是一个新兴的全球健康问题，由于胎儿畸形的可能性 在怀孕期间发生感染。ZIKV疫苗应优先引发中和抗体， (Abs)而不是非中和抗体，其可能加剧由ZIKV或相关登革热病毒引起的疾病 通过Ab依赖性增强（ADE）现象的菌株。Bjorkman实验室建议使用 了解ZIKV的Ab中和的结构基础，以设计潜在的疫苗免疫原 优化以引发中和抗体，同时通过最大限度地减少非- 中和抗体 Nussenzweig，Rice和Bjorkman实验室最近建立了一项合作， 并表征针对ZIKV包膜结构域III（ZEDIII）的Ab。一组ZIKV感染者， 已经发现高ZIKV中和Ab活性具有源自免疫球蛋白基因VH 3- 23/VK1-5。这些Ab中的几种在体内中和ZIKV并且在攻击和治疗中是有效的 小鼠实验通过这些Ab中和ZIKV的结构基础已经由以下揭示： Bjorkman实验室的Ab-EDIII复合物的晶体结构。结合ZEDIII的这些Ab的晶体结构 和登革1型病毒（DENV 1）的对应结构域揭示了一种共同的识别机制， ZIKV和DENV 1 EDIII侧脊。Bjorkman实验室将扩展这些努力，以解决和比较 结合至其靶抗原的另外的中和Ab的结构，分离的包膜结构域和 病毒体，以确定哪些特征与中和活性相关。抗原与 不同交叉反应性和效力的中和Ab（由Nussenzweig博士分离并由Dr. 水稻）将结晶和它们的结构特征进行比较，以确定病毒的脆弱性，以及 表征由弱或非中和抗体靶向的表位。 Bjorkman实验室建议使用ZIKV免疫原设计的种系靶向方法， 缓解ADE的可能性，这是一种通过识别和表征 VH 3 -23/VK 1 -5类抗ZIKV抗体。最初的免疫原设计工作将集中在侧脊 表位，其被有效的VH 3 -23/VK 1 -5 Ab识别。酵母文库筛选方法成功 用于HIV-1免疫原设计的ZEDIII变体将适于鉴定以更高亲和力与iGL结合的ZEDIII变体 VH3-23/VK1-5 Abs.非中和表位将通过添加N-连接聚糖或改变 以降低免疫原性。优化的抗原将被多聚化以产生候选免疫原。这些 免疫原的有效性和安全性将在临床前模型中与Dr. Nussenzweig和Rice。其目标是开发适合临床测试的免疫原。

Project Summary - Project 2 (PD: Pamela Bjorkman) Zika virus (ZIKV) infection is an emerging global health concern due to the potential for fetal abnormalities when infection occurs during pregnancy. A ZIKV vaccine should preferentially elicit neutralizing antibodies (Abs) rather than non-neutralizing Abs, which may exacerbate disease caused by ZIKV or related dengue virus strains through the phenomenon of Ab-dependent enhancement (ADE). The Bjorkman lab proposes to use knowledge of the structural basis for Ab neutralization of ZIKV to design potential vaccine immunogens optimized to elicit neutralizing Abs while reducing the risk of ADE by minimizing the production of non- neutralizing Abs. The Nussenzweig, Rice, and Bjorkman laboratories have recently-established a collaboration to isolate and characterize Abs against ZIKV Envelope Domain III (ZEDIII). A group of ZIKV-infected individuals with high ZIKV neutralizing Ab activity have been found to have Abs derived from immunoglobulin genes VH3- 23/VK1-5. Several of these Abs neutralize ZIKV in vivo and are effective in challenge and in treatment experiments in mice. The structural basis for ZIKV neutralization by these Abs has been revealed by the Bjorkman lab in crystal structures of Ab–EDIII complexes. The crystal structures of these Abs bound to ZEDIII and to the counterpart domain of dengue 1 virus (DENV1) revealed a common mechanism of recognition of the ZIKV and DENV1 EDIII lateral ridge. The Bjorkman lab will extend these efforts to solve and compare structures of additional neutralizing Abs bound to their target antigens, both isolated envelope domains and virions, in order to determine which features correlate with neutralizing activity. Complexes of antigen with neutralizing Abs of varying cross-reactivity and potency (isolated by Dr. Nussenzweig and evaluated by Dr. Rice) will be crystallized and their structural features compared to identify viral vulnerabilities as well as characterize epitopes targeted by weak or non-neutralizing antibodies. The Bjorkman lab proposes to use the germline-targeting approach for ZIKV immunogen design to mitigate the potential for ADE, an approach made possible by the identification and characterization of the VH3-23/VK1-5 class of anti-ZIKV Abs. Initial immunogen design efforts will be focused on the lateral ridge epitope, which is recognized by the potent VH3-23/VK1-5 Abs. Yeast library screening methods successfully used for HIV-1 immunogen design will be adapted to identify ZEDIII variants that bind with higher affinity to iGL versions of VH3-23/VK1-5 Abs. Non-neutralizing epitopes will be masked by adding N-linked glycans or altered to reduce immunogenicity. Optimized antigens will be multimerized to generate candidate immunogens. These immunogens will be evaluated for efficacy and safety in pre-clinical models in collaboration with Drs. Nussenzweig and Rice. The goal is to develop immunogens suitable to move towards clinical testing.