Chris Mok, team leader at HKU-Pasteur, published in Science with his team and with colleagues from Scripps Research Institute, USA, providing molecular insights into antibody recognition of SARS-CoV-2:
>>> A highly conserved cryptic epitope in the receptor-binding domains of SARS-CoV-2 and SARS-CoV
This paper sheds new light into antibody recognition of SARS-CoV-2. To this end, they used the Receptor Binding Domain (RBD) of the Spike protein of SARS-CoV-2, which is the region of the Spike protein that allows virus entry into cells by interacting with its specific receptor.
They took advantage of CR3022, a neutralizing monoclonal antibody previously isolated from a convalescent SARS patient, to determine its crystal structure in complex with the RBD of the SARS-CoV-2 Spike protein. This antibody targets a highly conserved epitope that enables cross-reactive binding with the Spike proteins of both SARS-CoV and SARS-CoV-2. Structural alignment of the CR3022-SARS-CoV-2 RBD complex with the ACE2-SARS-CoV RBD complex further indicates that binding of CR3022 would not clash with ACE2.
This analysis implies that the neutralization mechanism of CR3022 for SARS-CoV does not depend on direct blocking of receptor binding, which is consistent with the observation that CR3022 does not compete with ACE2 for binding to the RBD. Overall, this study provides insight into how SARS-CoV-2 can be targeted by the humoral immune response and revealed a conserved, but cryptic epitope shared between SARS-CoV-2 and SARS-CoV.