Influenza A hemagglutinin, Influenza B hemagglutinin, and SARS-CoV-2 spike glycoprotein (HA/S)

This target entry represents a combination of the primary surface glycoproteins from three major respiratory pathogens: Influenza A virus, Influenza B virus, and SARS-CoV-2. Influenza hemagglutinin (HA) is a trimeric protein responsible for binding host cell sialic acid receptors and mediating membrane fusion within endosomes (UniProt P03437 [1]; Mayo Clinic [3]). The SARS-CoV-2 spike (S) glycoprotein similarly facilitates viral entry by binding to the human angiotensin-converting enzyme 2 (ACE2) receptor (UniProt P0DTC2 [2]; Nature [5]). These proteins are the critical components of most current vaccines, as they are the primary targets for neutralizing antibodies that prevent infection (NIH [4]; Nature [5]). Because these viruses undergo frequent mutations—antigenic drift in influenza and the emergence of variants in SARS-CoV-2—these targets require constant monitoring and periodic vaccine updates to maintain efficacy (Mayo Clinic [3]; Nature [5]). Therapeutic interventions include monoclonal antibodies that block receptor binding domains and small molecules designed to inhibit the conformational changes necessary for fusion (NIH [4]). The development of multi-valent vaccines targeting both HA and S proteins is an active area of research to provide broad protection against seasonal and pandemic respiratory viruses. Citations: [1] https://www.uniprot.org/uniprotkb/P03437/entry [2] https://www.uniprot.org/uniprotkb/P0DTC2/entry [3] https://www.mayoclinic.org/diseases-conditions/flu/symptoms-causes/syc-20351719 [4] https://www.covid19treatmentguidelines.nih.gov/ [5] https://www.nature.com/articles/s41577-020-00434-6

Other names

HASpike proteinS proteinHemagglutinin antigenSurface glycoproteinViral fusion protein

Neutralization of viral entry by blocking the interaction between viral glycoproteins and host cell receptors (sialic acid or ACE2) or by inhibiting the conformational changes required for membrane fusion.