SUDV GP/CA45 cryo-EM map and structure

Filoviruses pose a significant threat to human health due to frequent outbreaks and high mortality. Although two vector-based vaccines are available for Ebola virus, a broadly protective filovirus vaccine remains elusive. Here, we evaluate a general strategy for stabilizing glycoprotein (GP) structures from Ebola, Sudan, and Bundibugyo orthoebolaviruses and Ravn orthomarburgvirus. A 3.2 Å crystal structure provides atomic-level details of the redesigned Ebola virus GP, while cryo-electron microscopy reveals how a pan-orthoebolavirus neutralizing antibody targets a conserved site on the stabilized Sudan virus GP (3.13 Å resolution), along with a low-resolution model of antibody-bound Ravn virus GP. A self-assembling protein nanoparticle (SApNP), I3-01v9, is redesigned at the N terminus to enable optimal surface display of filovirus GP trimers. Following detailed in vitro characterization, we examine the lymph node dynamics of Sudan virus GP and GP-presenting SApNPs in mice. Compared with the soluble trimer, SApNPs exhibit ~112-fold longer retention in lymph node follicles, up to 28-fold greater presentation on follicular dendritic cell dendrites, and up to 3-fold stronger germinal center reactions. Functional antibody responses induced by filovirus GP trimers and SApNPs bearing wild-type and modified glycans are assessed in mice. This study provides a foundation for next-generation filovirus vaccine development.

丝状病毒（Filovirus）因频繁暴发与极高致死率，对人类健康构成严重威胁。尽管目前已有两款针对埃博拉病毒的载体疫苗，但具备广谱保护效力的丝状病毒疫苗仍未问世。本研究针对埃博拉病毒、苏丹病毒、本迪布焦正埃博拉病毒（orthoebolavirus）以及拉夫尼正马尔堡病毒（orthomarburgvirus）的糖蛋白（glycoprotein, GP）结构，评估了一种通用的稳定化策略。分辨率3.2 Å的晶体结构揭示了经重新设计的埃博拉病毒GP的原子级细节；冷冻电子显微镜（cryo-electron microscopy）则解析了广谱正埃博拉病毒中和抗体如何结合稳定化苏丹病毒GP的保守位点（分辨率3.13 Å），同时获得了抗体结合拉夫尼病毒GP的低分辨率模型。研究团队对自组装蛋白纳米颗粒（self-assembling protein nanoparticle, SApNP）I3-01v9的N端进行重新设计，以实现丝状病毒GP三聚体的最优表面展示。在完成详尽的体外表征后，本研究在小鼠体内考察了苏丹病毒GP以及展示GP的SApNP的淋巴结动态变化。与可溶性三聚体相比，SApNP在淋巴结滤泡中的滞留时间延长约112倍，在滤泡树突状细胞树突上的展示水平最高提升28倍，生发中心反应强度最高增强3倍。本研究还在小鼠体内评估了丝状病毒GP三聚体以及携带野生型与修饰型聚糖的SApNP所诱导的功能性抗体应答。本研究为下一代丝状病毒疫苗的开发奠定了基础。