Structure and function analysis of a potent human neutralizing antibody CA521 FALA against SARS-CoV-2.
Song, D., Wang, W., Dong, C., Ning, Z., Liu, X., Liu, C., Du, G., Sha, C., Wang, K., Lu, J., Sun, B., Zhao, Y., Wang, Q., Xu, H., Li, Y., Shen, Z., Jiao, J., Wang, R., Tian, J., Liu, W., Wang, L., Deng, Y.Q., Dou, C.(2021) Commun Biol 4: 500-500
- PubMed: 33893388 
- DOI: https://doi.org/10.1038/s42003-021-02029-w
- Primary Citation of Related Structures:  
7E23 - PubMed Abstract: 
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the ongoing COVID-19 pandemic, which has resulted in more than two million deaths at 2021 February . There is currently no approved therapeutics for treating COVID-19. The SARS-CoV-2 Spike protein is considered a key therapeutic target by many researchers. Here we describe the identification of several monoclonal antibodies that target SARS-CoV-2 Spike protein. One human antibody, CA521 FALA , demonstrated neutralization potential by immunizing human antibody transgenic mice. CA521 FALA showed potent SARS-CoV-2-specific neutralization activity against SARS-CoV-2 pseudovirus and authentic SARS-CoV-2 infection in vitro. CA521 FALA also demonstrated having a long half-life of 9.5 days in mice and 9.3 days in rhesus monkeys. CA521 FALA inhibited SARS-CoV-2 infection in SARS-CoV-2 susceptible mice at a therapeutic setting with virus titer of the lung reduced by 4.5 logs. Structural analysis by cryo-EM revealed that CA521 FALA recognizes an epitope overlapping with angiotensin converting enzyme 2 (ACE2)-binding sites in SARS-CoV-2 RBD in the Spike protein. CA521 FALA blocks the interaction by binding all three RBDs of one SARS-CoV-2 spike trimer simultaneously. These results demonstrate the importance for antibody-based therapeutic interventions against COVID-19 and identifies CA521 FALA a promising antibody that reacts with SARS-CoV-2 Spike protein to strongly neutralize its activity.
Organizational Affiliation: 
Antibody Research and Development Center, Shandong Boan Biotechnology Co., Ltd., Yantai, China.