Hemagglutinin and SARS-CoV-2 spike protein

Hemagglutinin (HA) and the SARS-CoV-2 spike (S) protein are the primary surface glycoproteins of the Influenza virus and the SARS-CoV-2 virus, respectively (UniProt P03435, P0DTC2). Both proteins serve as the critical machinery for viral attachment and entry into host cells; HA binds to sialic acid receptors on the host cell surface, while the S protein targets the Angiotensin-Converting Enzyme 2 (ACE2) receptor (PubMed: 32142651, 32155444). Because they are the most exposed components of the virion, they are the primary targets for neutralizing antibodies induced by infection or vaccination. Therapeutic strategies targeting these proteins include monoclonal antibodies that block receptor binding and small molecule inhibitors like Umifenovir that interfere with membrane fusion (PubMed: 32164057). However, both proteins are subject to significant evolutionary pressure, leading to mutations that can result in vaccine escape and reduced drug efficacy (Nature: 10.1038/s41577-020-00479-7). This entry is considered incorrect as it combines two distinct viral targets from different families into a single classification.

Other names

HAS proteinInfluenza hemagglutininSARS-CoV-2 surface glycoproteinSpike glycoprotein

Neutralization of viral entry by blocking receptor binding or inhibiting membrane fusion.