Project 2

项目摘要--项目2(PD：Pamela Bjorkman) 寨卡病毒(ZIKV)感染是一个新出现的全球健康问题，因为它可能导致胎儿畸形 当怀孕期间发生感染时。ZIKV疫苗应优先诱导中和抗体 (ABS)而不是非中和抗体，这可能会加剧ZIKV或相关登革热病毒引起的疾病 菌株通过抗体依赖增强(ADE)现象。比约克曼实验室建议使用 了解ZIKV抗体中和的结构基础以设计潜在的疫苗免疫原 优化以诱导中和抗体，同时通过最大限度地减少非 中和Abs。 努森茨韦格、赖斯和比约克曼的实验室最近建立了一项合作，以分离 并鉴定了抗ZIKV包膜结构域III(ZEDIII)的单抗。一群感染寨卡病毒的人 高活性的ZIKV中和抗体被发现来自免疫球蛋白基因VH3- 23/VK1-5。其中几种抗体在体内中和寨卡病毒，并在攻击和治疗中有效 在老鼠身上做实验。这些抗体中和ZIKV的结构基础已被揭示 Bjorkman实验室研究了单抗-EDIII络合物的晶体结构。这些抗体与ZEDIII结合的晶体结构 与登革1型病毒(DENV1)的对应结构域揭示了识别登革1型病毒的共同机制 ZIKV和DENV1 EDIII侧脊。比约克曼实验室将扩展这些努力，以解决和比较 与其靶抗原结合的额外中和抗体的结构，既有分离的包膜结构域，也有 病毒粒子，以确定哪些特征与中和活性相关。抗原与抗原的复合体 具有不同交叉反应和效力的中和抗体(由Nussenzweig博士分离并由Dr. 水稻)将被结晶并比较它们的结构特征以识别病毒脆弱性以及 确定弱抗体或非中和抗体所针对的表位。 比约克曼实验室建议将生殖系靶向方法用于ZIKV免疫原设计，以 减少ADE的可能性，这是一种可能的方法，通过确定和表征 VH3-23/VK1-5类抗ZIKV单抗。最初的免疫原设计工作将集中在侧脊上 表位，由VH3-23/VK1-5抗体识别。酵母文库筛选方法成功 用于HIV-1免疫原设计将用于识别与IGL结合更高亲和力的ZEDIII变体 VH3-23/VK1-5抗体版本。非中和表位将通过添加N-连接的多糖或改变而被屏蔽 以降低免疫原性。优化的抗原将被多聚体产生候选免疫原。这些 免疫原将在临床前模型中与Dr. 努森茨韦格和赖斯。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.