Isolation of and Characterization of Neutralizing Antibodies to Covid-19 from a Large Human Naïve scFv Phage Display Library

Yuan, Andy Q.; Zhao, Likun; Bai, Lili; Meng, Qingwu; Wen, Zhenguo; Li, Yanhu; Guo, Daqing; Zhen, Shanshan; Chen, Xiaojun; Yang, Ji; Xue, Xiaoying

SARS-CoV-2 (Covid-19) has caused currently ongoing global plague and imposed great challenges to health managing systems all over the world, with millions of infections and hundreds of thousands of deaths. In addition to racing to develop vaccines, neutralizing antibodies (nAbs) to this virus have been extensively sought and are expected to provide another prevention and therapy tool against this frantic pandemic. To offer fast isolation and shortened early development, a large human naïve phage display antibody library, was built and used to screen specific nAbs to the receptor-binding domain, RBD, the key for Covid-19 virus entry through a human receptor, ACE2. The obtained RBD-specific antibodies were characterized by epitope mapping, FACS and neutralization assay. Some of the antibodies demonstrated spike-neutralizing property and ACE2-competitiveness. Our work proved that RBD-specific neutralizing binders from human naïve antibody phage display library are promising candidates to for further Covid-19 therapeutics development.