Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally as a severe pandemic. The interaction between receptor binding domain (RBD) of SARS-CoV-2 spike (S) protein and angiotensin converting enzyme 2 (ACE2) on host cells plays an important role in virus attachment, fusion and entry into target cells. Blocking the interaction between S protein and ACE2 may reduce the virus infection.
In a recent study published in Cellular & Molecular Immunology on May 6, 2021, a research team led by Dr. CHEN JianFeng from Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, has reported the identification and characterization of a human monoclonal antibody (mAb) C8 that blocks S protein-ACE2 interaction. C8 was discovered by screening a human single-chain variable fragment phage library using S-RBD as target and converted to a full length human IgG1. In addition to inhibit S-RBD–ACE2 binding, C8 IgG efficiently prevented the infection of ACE2-expressing 293T cells by SARS-CoV-2 pseudoviruses with a half-maximal inhibitory concentration (IC50) of 0.91 μg/ml. Taken together, C8 IgG is an engineered human mAb against SARS-CoV-2 S-RBD, which inhibits SARS-CoV-2 pseudovirus infection of cells by blocking S protein-ACE2 interaction. Structural optimization and further research on mAb C8 may offer potential for prevention and treatment of COVID-19.