SARS-CoV-2 spike protein conserved non-ACE2-binding epitopes (SARS-CoV-2 S-protein conserved epitopes)

The SARS-CoV-2 spike (S) protein is the primary surface protein responsible for viral entry into host cells. While much focus is on the Receptor Binding Domain (RBD) and its interaction with the ACE2 receptor, non-ACE2-dependent conserved epitopes represent critical alternative therapeutic targets (Nature, 2020, doi:10.1038/s41586-020-2349-y). These epitopes are located in regions such as the N-terminal domain (NTD), the S2 subunit—including the fusion peptide and stem helix—and cryptic sites within the RBD that do not directly overlap with the ACE2 binding motif (Science, 2021, doi:10.1126/science.abi9215). Because these regions are often highly conserved across different variants of concern (VOCs) and even other sarbecoviruses, they are prime targets for broadly neutralizing antibodies (bnAbs) and next-generation vaccines (Nature Communications, 2022, doi:10.1038/s41467-022-32374-3). Drugs targeting these epitopes, such as Sotrovimab, typically work by preventing the conformational changes required for membrane fusion or by providing steric hindrance that blocks viral progression (Cell, 2021, doi:10.1016/j.cell.2021.09.010). Targeting these conserved sites helps mitigate the impact of viral evolution and escape mutations that frequently occur in the immunodominant ACE2-binding regions.

Other names

SARS-CoV-2 S2 subunit epitopesSARS-CoV-2 NTD conserved epitopesSARS-CoV-2 fusion peptideSARS-CoV-2 stem helixSARS-CoV-2 S protein cryptic epitopesPan-sarbecovirus conserved epitopes

Neutralization of viral activity by inhibiting membrane fusion, preventing conformational changes (pre-to-post-fusion transition), or inducing steric hindrance of viral-host interactions.