Abstract
Neutralizing antibodies (NAbs) are believed to be promising prophylactic and therapeutic treatment against the coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we reported two mouse monoclonal antibodies 7 Eb-4G and 1Ba-3H that specifically recognized the receptor-binding domain (RBD) of SARS-CoV-2 spike (S) protein without exhibiting cross-reactivity with the S proteins of SARS-CoV and MERS-CoV. The binding epitopes of 7 Eb-4G and 1Ba-3H were respectively located in the regions of residues 457-476 and 477-496 in the S protein. Only 1Ba-3H exhibited the neutralizing activity for preventing the pseudotyped lentivirus from binding to the angiotensin-converting enzyme 2 (ACE2)-transfected HEK293T cells. The competitive ELISA further showed that 1Ba-3H interfered with the binding between RBD and ACE2. Epitope mapping experiments demonstrated that a single alanine replacement at residues 480, 482, 484, 485, and 488-491 in the RBD abrogated 1Ba-3H binding. 1Ba-3H exhibited the neutralizing activity against the wild-type, Alpha, Delta, and Epsilon variants of SARS-CoV-2, but lost the neutralizing activity against Gamma variant in the plaque reduction assay. On the contrary, 1Ba-3H enhanced the cellular infection of Gamma variant in a dose-dependent manner. Our findings suggest that the antibody-dependent enhancement of infection mediated by the RBD-specific antibody for different SARS-CoV-2 variants must be considered while developing the NAb.
Keywords: ACE2; Antibody-dependent enhancement; COVID-19; Neutralizing antibody; SARS-CoV-2; Spike receptor binding domain.
【저자키워드】 COVID-19, neutralizing antibody, SARS-CoV-2, ACE2, Antibody-dependent enhancement, Spike receptor binding domain., 【초록키워드】 coronavirus disease, neutralizing antibody, Coronavirus disease 2019, coronavirus, S protein, Neutralizing antibodies, spike, antibody, SARS-CoV, Antibody-dependent enhancement, variant, SARS-CoV-2 variant, Infection, Delta, Prophylactic, severe acute respiratory syndrome Coronavirus, monoclonal antibodies, MERS-CoV, angiotensin-converting enzyme 2, ELISA, Receptor binding domain, cross-reactivity, Protein, Epitopes, Neutralizing activity, Region, Receptor-binding domain, SARS-CoV-2 variants, RBD, lentivirus, Epsilon, Gamma, Alpha, receptor, experiment, mouse monoclonal antibody, respiratory, epitope, binding, SARS-CoV-2 spike, Angiotensin-converting enzyme, cellular, angiotensin, reduction, acute respiratory syndrome, Spike receptor binding domain, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, dose-dependent manner, NAbs, residue, S proteins, Alanine, contrary, wild-type, residues, HEK293T cells, pseudotyped, Therapeutic treatment, variants of SARS-CoV-2, caused, reported, exhibited, demonstrated, the RBD, the receptor-binding domain, the S protein, abrogated, exhibiting, binding epitope, 【제목키워드】 SARS-COV-2 infection, monoclonal antibody, spike receptor-binding domain,