SARS-CoV-2 Spike protein receptor-binding domain epitope 2 (SARS-CoV-2 RBD Epitope 2)

The SARS-CoV-2 Spike protein receptor-binding domain (RBD) epitope 2 is a critical antigenic site located on the spike glycoprotein of the SARS-CoV-2 virus (Barnes et al., 2020, Nature). This epitope is specifically classified as a Class 2 site, characterized by its overlap with the angiotensin-converting enzyme 2 (ACE2) binding footprint (Starr et al., 2021, Science). Unlike Class 1 epitopes, Epitope 2 is accessible to neutralizing antibodies in both the 'up' and 'down' conformations of the RBD (Yuan et al., 2020, Science). Its primary biological function is to facilitate the attachment of the virus to the host cell's ACE2 receptor, a prerequisite for viral entry and infection (Harvey et al., 2021, Nature Reviews Microbiology). Consequently, it serves as a major target for therapeutic monoclonal antibodies like Casirivimab and Bamlanivimab (FDA, 2021). These drugs work by sterically hindering the RBD-ACE2 interaction, thereby preventing the virus from infecting healthy cells. However, this epitope is a hotspot for mutations, such as the E484K substitution, which can lead to significant immune escape and reduced drug efficacy (Greaney et al., 2021, Cell Host & Microbe). Monitoring these mutations is essential for maintaining the efficacy of treatments and vaccines against evolving variants.

Other names

Class 2 RBD epitopeSARS-CoV-2 RBD antigenic site IIACE2-binding site epitope (Class 2)RBD Class 2 epitopeSpike RBD Epitope 2

Neutralization of viral particles by sterically blocking the interaction between the viral receptor-binding domain (RBD) and the host cell receptor ACE2.