State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, 200031, China.
Key Laboratory of Medical Molecular Virology (MOE/MOH), Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
Sci China Life Sci. 2023 Apr;66(4):729-742. doi: 10.1007/s11427-022-2250-0. Epub 2023 Feb 23.
Respiratory syncytial virus (RSV) continues to pose serious threats to pediatric populations due to the lack of a vaccine and effective antiviral drugs. RSV fusion (F) glycoprotein mediates viral-host membrane fusion and is a key target for neutralizing antibodies. We generated 23 full-human monoclonal antibodies (hmAbs) against prefusion F protein (pre-F) from a healthy adult with natural RSV infection by single B cell cloning technique. A highly potent RSV-neutralizing hmAb, named as 25-20, is selected, which targets a new site Ø-specific epitope. Site-directed mutagenesis and structural modelling analysis demonstrated that 25-20 mainly targets a highly conserved hydrophobic region located at the a4 helix and a1 helix of pre-F, indicating a site of vulnerability for drug and vaccine design. It is worth noting that 25-20 uses an unreported inferred germline (iGL) that binds very poorly to pre-F, thus high levels of somatic mutations are needed to gain high binding affinity with pre-F. Our observation helps to understand the evolution of RSV antibody during natural infection. Furthermore, by in silico prediction and experimental verification, we optimized 25-20 with KD values as low as picomolar range. Therefore, the optimized 25-20 represents an excellent candidate for passive protection against RSV infection.
呼吸道合胞病毒（RSV）由于缺乏疫苗和有效的抗病毒药物，继续对儿科人群构成严重威胁。RSV 融合（F）糖蛋白介导病毒-宿主膜融合，是中和抗体的关键靶标。我们通过单细胞克隆技术从自然 RSV 感染的健康成年人中产生了 23 种针对预融合 F 蛋白（pre-F）的全人源单克隆抗体（hmAb）。我们选择了一种高效的 RSV 中和 hmAb，命名为 25-20，该抗体针对一个新的 Ø 特异性表位。定点突变和结构建模分析表明，25-20 主要针对 pre-F 的 a4 螺旋和 a1 螺旋上一个高度保守的疏水区，表明这是药物和疫苗设计的脆弱部位。值得注意的是，25-20 使用了一个报道较少的推断胚系（iGL），与 pre-F 的结合能力很差，因此需要大量的体细胞突变才能获得与 pre-F 的高结合亲和力。我们的观察有助于了解自然感染过程中 RSV 抗体的进化。此外，通过计算机预测和实验验证，我们将 25-20 优化至皮摩尔级别的 KD 值。因此，优化后的 25-20 是针对 RSV 感染进行被动保护的优秀候选物。
