Fan Chengcheng, Keeffe Jennifer R, Malecek Kathryn E, Cohen Alexander A, West Anthony P, Baharani Viren A, Rorick Annie V, Gao Han, Gnanapragasam Priyanthi N P, Rho Semi, Alvarez Jaasiel, Segovia Luisa N, Hatziioannou Theodora, Bieniasz Paul D, Bjorkman Pamela J
Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA.
bioRxiv. 2025 Jan 3:2025.01.02.631145. doi: 10.1101/2025.01.02.631145.
Therapeutic monoclonal antibodies (mAbs) against SARS-CoV-2 become obsolete as spike substitutions reduce antibody binding. To induce antibodies against conserved receptor-binding domain (RBD) regions for protection against SARS-CoV-2 variants of concern and zoonotic sarbecoviruses, we developed mosaic-8b RBD-nanoparticles presenting eight sarbecovirus RBDs arranged randomly on a 60-mer nanoparticle. Mosaic-8b immunizations protected animals from challenges from viruses whose RBDs were matched or mismatched to those on nanoparticles. Here, we describe neutralizing mAbs from mosaic-8b-immunized rabbits, some on par with Pemgarda (the only currently FDA-approved therapeutic mAb). Deep mutational scanning, selection of spike resistance mutations, and cryo-EM structures of spike-antibody complexes demonstrated targeting of conserved epitopes. Rabbit mAbs included critical D-gene segment features in common with human anti-RBD mAbs, despite rabbit genomes lacking an equivalent human D-gene segment. Thus, mosaic RBD-nanoparticle immunization coupled with multiplexed screening represent an efficient way to generate and select therapeutic pan-sarbecovirus and pan-SARS-2 variant mAbs.
随着刺突蛋白的替换降低抗体结合能力，针对严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的治疗性单克隆抗体（mAb）逐渐过时。为了诱导针对保守受体结合域（RBD）区域的抗体，以预防关注的SARS-CoV-2变体和人畜共患的sarbecovirus病毒，我们开发了镶嵌8b RBD纳米颗粒，该颗粒在一个60聚体纳米颗粒上随机排列了8种sarbecovirus病毒的RBD。镶嵌8b免疫可保护动物免受RBD与纳米颗粒上的RBD匹配或不匹配的病毒的攻击。在此，我们描述了从接受镶嵌8b免疫的兔子中获得的中和性单克隆抗体，其中一些与Pemgarda（目前唯一获得美国食品药品监督管理局批准的治疗性单克隆抗体）相当。深度突变扫描、刺突蛋白抗性突变的选择以及刺突蛋白-抗体复合物的冷冻电镜结构证明了这些抗体靶向保守表位。兔源单克隆抗体具有与人类抗RBD单克隆抗体相同的关键D基因片段特征，尽管兔基因组中缺乏与之等效的人类D基因片段。因此，镶嵌RBD纳米颗粒免疫结合多重筛选是产生和选择治疗性泛sarbecovirus病毒和泛SARS-CoV-2变体单克隆抗体的有效方法。
