Journal Article

A synthetic nanobody targeting RBD protects hamsters from SARS-CoV-2 infection

Raoul, Hervé, Yao, Hebang, Rockx, Barry, Lan, Jiaming, Seeger, Markus A., Li, Tingting, van Vlissingen, Martje Fentener, Bi, Yuhai, Cong, Yao, Wong, Gary, Zhou, Bingjie, Shen, Quan, Li, Dianfan, Wang, Yanxing, Zhang, Ning, Tian, Xiao-Xu, Kuo, Shu-Ming, Liu, Caixuan, Cai, Hongmin, Kuiken, Thijs, Richard, Audrey S., Gong, Yuhuan, Lai, Yanling, GeurtsvanKessel, Corine H., Hutter, Cedric A. J., Han, Wenyu, Zhao, Yapei, Qin, Wenming, Bao, Juan, Lavillette, Dimitri, Peng, Chao, Wang, Yifan

2021

Overview

SARS-CoV-2, the causative agent of COVID-19 1 , features a receptor-binding domain (RBD) for binding to the host cell ACE2 protein 1 – 6 . Neutralizing antibodies that block RBD-ACE2 interaction are candidates for the development of targeted therapeutics 7 – 17 . Llama-derived single-domain antibodies (nanobodies, ~15 kDa) offer advantages in bioavailability, amenability, and production and storage owing to their small sizes and high stability. Here, we report the rapid selection of 99 synthetic nanobodies (sybodies) against RBD by in vitro selection using three libraries. The best sybody, MR3 binds to RBD with high affinity ( K D  = 1.0 nM) and displays high neutralization activity against SARS-CoV-2 pseudoviruses (IC 50  = 0.42 μg mL −1 ). Structural, biochemical, and biological characterization suggests a common neutralizing mechanism, in which the RBD-ACE2 interaction is competitively inhibited by sybodies. Various forms of sybodies with improved potency have been generated by structure-based design, biparatopic construction, and divalent engineering. Two divalent forms of MR3 protect hamsters from clinical signs after live virus challenge and a single dose of the Fc-fusion construct of MR3 reduces viral RNA load by 6 Log 10 . Our results pave the way for the development of therapeutic nanobodies against COVID-19 and present a strategy for rapid development of targeted medical interventions during an outbreak. Here, the authors report the engineering, structural and biological characterization of synthetic nanobodies (sybodies) that display potent therapeutic activity against SARS-CoV-2 infection in animal models via targeting the virus receptor-binding domain.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 631/326/596/4130 / 631/45/535/1266 / 82/1 / 82/80 / 82/83 / ACE2 / Angiotensin-converting enzyme 2 / Angiotensin-Converting Enzyme 2 - metabolism / Animal models / Animals / Antibodies / Antibodies, Neutralizing - immunology / Antibodies, Neutralizing - pharmacology / Antibodies, Neutralizing - ultrastructure / Antibodies, Viral - immunology / Antibodies, Viral - pharmacology / Antibodies, Viral - ultrastructure / Binding / Binding Sites - immunology / Bioavailability / COVID-19 / COVID-19 - immunology / COVID-19 - prevention & control / COVID-19 - virology / Cryoelectron Microscopy / Crystallography, X-Ray / Emerging diseases / Female / Hamsters / Human health and pathology / Humanities and Social Sciences / Humans / Immunology / Immunotherapy / Infectious diseases / Life Sciences / Mass Spectrometry - methods / Mesocricetus / Mice / Mice, Inbred C57BL / Microbiology and Parasitology / multidisciplinary / Nanobodies / Neutralization / Neutralization Tests / Neutralizing / Protein Binding - drug effects / Receptors / Receptors, Virus - metabolism / SARS-CoV-2 - immunology / SARS-CoV-2 - metabolism / SARS-CoV-2 - physiology / Science / Science (multidisciplinary) / Severe acute respiratory syndrome coronavirus 2 / Single-Domain Antibodies - chemistry / Single-Domain Antibodies - immunology / Single-Domain Antibodies - metabolism / Structural analysis / Viral diseases / Virology / Viruses