tetano
Editor, Senior Moderator
Cell Rep
. 2021 Oct 8;109881.
doi: 10.1016/j.celrep.2021.109881. Online ahead of print.
Structural mechanism of SARS-CoV-2 neutralization by two murine antibodies targeting the RBD
John M Errico[SUP] 1 [/SUP], Haiyan Zhao[SUP] 1 [/SUP], Rita E Chen[SUP] 2 [/SUP], Zhuoming Liu[SUP] 3 [/SUP], James Brett Case[SUP] 4 [/SUP], Meisheng Ma[SUP] 1 [/SUP], Aaron J Schmitz[SUP] 1 [/SUP], Michael J Rau[SUP] 5 [/SUP], James A J Fitzpatrick[SUP] 6 [/SUP], Pei-Yong Shi[SUP] 7 [/SUP], Michael S Diamond[SUP] 8 [/SUP], Sean P J Whelan[SUP] 3 [/SUP], Ali H Ellebedy[SUP] 9 [/SUP], Daved H Fremont[SUP] 10 [/SUP]
Affiliations
Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has necessitated the rapid development of antibody-based therapies and vaccines as countermeasures. Here, we use cryoelectron microscopy (cryo-EM) to characterize two protective anti-SARS-CoV-2 murine monoclonal antibodies (mAbs) in complex with the spike protein, revealing similarities between epitopes targeted by human and murine B cells. The more neutralizing mAb, 2B04, binds the receptor-binding motif (RBM) of the receptor-binding domain (RBD) and competes with angiotensin-converting enzyme 2 (ACE2). By contrast, 2H04 binds adjacent to the RBM and does not compete for ACE2 binding. Naturally occurring sequence variants of SARS-CoV-2 and corresponding neutralization escape variants selected in vitro map to our structurally defined epitopes, suggesting that SARS-CoV-2 might evade therapeutic antibodies with a limited set of mutations, underscoring the importance of combination mAb therapeutics. Finally, we show that 2B04 neutralizes SARS-CoV-2 infection by preventing ACE2 engagement, whereas 2H04 reduces host cell attachment without directly disrupting ACE2-RBM interactions, providing distinct inhibitory mechanisms used by RBD-specific mAbs.
Keywords: ACE2; COVID-19; RBD; SARS-CoV-2; antibody neutralization; biolayer interferometry; cryo-EM; spike; variants of concern.
. 2021 Oct 8;109881.
doi: 10.1016/j.celrep.2021.109881. Online ahead of print.
Structural mechanism of SARS-CoV-2 neutralization by two murine antibodies targeting the RBD
John M Errico[SUP] 1 [/SUP], Haiyan Zhao[SUP] 1 [/SUP], Rita E Chen[SUP] 2 [/SUP], Zhuoming Liu[SUP] 3 [/SUP], James Brett Case[SUP] 4 [/SUP], Meisheng Ma[SUP] 1 [/SUP], Aaron J Schmitz[SUP] 1 [/SUP], Michael J Rau[SUP] 5 [/SUP], James A J Fitzpatrick[SUP] 6 [/SUP], Pei-Yong Shi[SUP] 7 [/SUP], Michael S Diamond[SUP] 8 [/SUP], Sean P J Whelan[SUP] 3 [/SUP], Ali H Ellebedy[SUP] 9 [/SUP], Daved H Fremont[SUP] 10 [/SUP]
Affiliations
- PMID: 34655519
- DOI: 10.1016/j.celrep.2021.109881
Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has necessitated the rapid development of antibody-based therapies and vaccines as countermeasures. Here, we use cryoelectron microscopy (cryo-EM) to characterize two protective anti-SARS-CoV-2 murine monoclonal antibodies (mAbs) in complex with the spike protein, revealing similarities between epitopes targeted by human and murine B cells. The more neutralizing mAb, 2B04, binds the receptor-binding motif (RBM) of the receptor-binding domain (RBD) and competes with angiotensin-converting enzyme 2 (ACE2). By contrast, 2H04 binds adjacent to the RBM and does not compete for ACE2 binding. Naturally occurring sequence variants of SARS-CoV-2 and corresponding neutralization escape variants selected in vitro map to our structurally defined epitopes, suggesting that SARS-CoV-2 might evade therapeutic antibodies with a limited set of mutations, underscoring the importance of combination mAb therapeutics. Finally, we show that 2B04 neutralizes SARS-CoV-2 infection by preventing ACE2 engagement, whereas 2H04 reduces host cell attachment without directly disrupting ACE2-RBM interactions, providing distinct inhibitory mechanisms used by RBD-specific mAbs.
Keywords: ACE2; COVID-19; RBD; SARS-CoV-2; antibody neutralization; biolayer interferometry; cryo-EM; spike; variants of concern.