Hemagglutinin (HA) of G4 Eurasian avian-like H1N1 swine influenza A virus (HA)

Hemagglutinin (HA) is the primary surface glycoprotein of the G4 Eurasian avian-like (EA) H1N1 swine influenza virus, a genotype that has become predominant in swine populations and poses a significant zoonotic risk to humans (Sun et al., 2020, PNAS). The protein functions as a homotrimer, where each monomer is composed of two subunits, HA1 and HA2, responsible for receptor binding and membrane fusion, respectively (Kadam & Wilson, 2012, Science). Specifically, the G4 EA H1N1 HA has evolved to preferentially bind to alpha-2,6-linked sialic acids, which are prevalent in the human upper respiratory tract, facilitating efficient transmission and replication in human cells (Sun et al., 2020, PNAS). As the major antigen of the virus, HA is the central target for the host immune response and the primary component of seasonal and pre-pandemic vaccines. Therapeutic strategies targeting HA include small-molecule fusion inhibitors like Umifenovir and various monoclonal antibodies designed to neutralize the virus by blocking its attachment or entry into host cells (Blaising et al., 2014, Antiviral Res). Monitoring mutations in the HA head domain is essential for assessing the pandemic risk and maintaining vaccine efficacy against this emerging strain.

Other names

G4 EA H1N1 HemagglutininH1 HemagglutininSurface glycoprotein HAHemagglutinin protein

Inhibition of viral attachment to host cell sialic acid receptors and prevention of pH-dependent membrane fusion within the endosome (Blaising et al., 2014; Kadam & Wilson, 2012).