Coronavirus disease 2019 (COVID-19) has become a worldwide threat to humans, and neutralizing antibodies have therapeutic potential. We have purified more than 1,000 memory B cells specific to SARS-CoV-2 S1 or its RBD (receptor binding domain) and obtain 729 paired heavy- and light-chain fragments. Among these, 178 antibodies test positive for antigen binding, and the majority of the top 17 binders with EC₅₀ below 1 nM are RBD binders. Furthermore, we identify 11 neutralizing antibodies, eight of which show IC₅₀ within 10 nM, and the best one, 414-1, with IC₅₀ of 1.75 nM. Through epitope mapping, we find three main epitopes in RBD recognized by these antibodies, and epitope-B antibody 553-15 could substantially enhance the neutralizing abilities of most of the other antibodies. We also find that 515-5 could cross neutralize the SARS-CoV pseudovirus. Altogether, our study provides 11 potent human neutralizing antibodies for COVID-19 as therapeutic candidates.

2019年冠状病毒病（COVID-19）已成为对人类的全球威胁，中和抗体具有治疗潜力。我们已经纯化了1000多种SARS-CoV-2 S1或其RBD（受体结合域）特异的记忆B细胞，并获得729对成对的重链和轻链片段。在这些抗体中，有178种抗体的抗原结合测试呈阳性，并且EC ₅₀低于1 nM的前17种结合剂中的大多数是RBD结合剂。此外，我们鉴定出11种中和抗体，其中8种显示IC ₅₀在10 nM之内，而最好的一种抗体414-1与IC ₅₀为1.75 nM。通过表位作图，我们发现了RBD中三个主要的表位被这些抗体识别，表位B抗体553-15可以显着增强大多数其他抗体的中和能力。我们还发现515-5可以交叉中和SARS-CoV假病毒。总共，我们的研究提供了11种针对COVID-19的有效人类中和抗体作为治疗候选药物。