Hemagglutinin glycoprotein, H1 subtype (G4 EA H1N1 swine influenza A virus) (HA)

The Hemagglutinin (HA) glycoprotein of the G4 EA H1N1 swine influenza A virus is a critical surface protein responsible for viral entry into host cells (Sun et al., 2020, PubMed: 32591431). It functions as a lectin that binds to sialic acid receptors on the host cell surface, specifically showing a high affinity for human-type alpha-2,6-linked sialic acids, which facilitates zoonotic transmission (UniProt: P03452). Following binding, the HA protein undergoes a pH-dependent conformational change in the endosome to mediate the fusion of the viral envelope with the host cell membrane (CDC, 2020). As the primary target for neutralizing antibodies, HA is the central component of influenza vaccines and a key focus for the development of entry inhibitors like Umifenovir (PubChem CID: 131411). The G4 lineage is of particular concern due to its reassortant nature, containing genes from the 2009 H1N1 pandemic strain, which enhances its infectivity in human airway epithelial cells (Nature, 2020). Targeting this protein is essential for pandemic preparedness and the development of cross-reactive therapeutic interventions.

Other names

H1 hemagglutininG4 EA H1N1 HASurface glycoproteinHemagglutinin protein

Inhibition of viral-host membrane fusion and blockade of sialic acid receptor binding sites to prevent viral entry into host cells.