Influenza A virus (H1N1) hemagglutinin (HA) (HA)

Hemagglutinin (HA) is the primary surface glycoprotein of the Influenza A virus (H1N1) and was the central component of vaccines developed during the 2009 pandemic (UniProt: P03452). It functions as a class I fusion protein, responsible for binding the virus to sialic acid receptors on the surface of host respiratory cells and mediating the fusion of the viral and endosomal membranes (PubMed: 19855010). As a vaccine antigen, HA acts as an immunogen that triggers the production of neutralizing antibodies, primarily targeting the highly variable head domain to block viral entry (CDC, 2009). The 2009 H1N1 strain (A/California/04/2009) represented a unique reassortant lineage, making its HA a critical target for global immunization efforts (WHO, 2009). Understanding the structural stability and antigenic sites of this protein is essential for designing effective seasonal and pandemic vaccines, as well as developing universal flu therapeutics targeting the conserved stem region (PubMed: PMC6117404).

Other names

H1N1 hemagglutinin2009 pandemic HAH1 hemagglutininHemagglutinin surface glycoproteinHA1/HA2 subunit

Induction of neutralizing antibodies that bind to the HA globular head, preventing viral attachment to host sialic acid receptors and subsequent endocytosis (PubMed: PMC3063653). It also serves as a target for small-molecule fusion inhibitors that stabilize the prefusion conformation (PubMed: PMC6117404).