S309

S309 is a human monoclonal antibody originally isolated from memory B cells of a patient who recovered from SARS in 2003, which potently neutralizes SARS-CoV-2 and other related sarbecoviruses by targeting a conserved epitope on the spike protein receptor-binding domain. Structural and functional studies show that S309 binds a glycan-containing site on the spike protein near, but distinct from, the receptor-binding motif, allowing cross-reactive recognition of multiple coronaviruses and inhibition of viral entry into host cells.[1][2][4] S309 served as the parental antibody for the clinically used derivative sotrovimab (VIR-7831), which incorporates Fc modifications and was co-developed by Vir Biotechnology and GSK, but S309 itself is primarily used as a research and preclinical tool for broad coronavirus neutralization and epitope mapping rather than as an approved therapeutic.[3][4][5]

Other names

SARS-CoV/SARS-CoV-2 neutralizing antibody S309