Hemagglutinin protein of Influenza A(H3N2)

Hemagglutinin (HA) is a surface glycoprotein and the principal antigenic determinant of the influenza A(H3N2) virus. It mediates viral attachment to host cells and subsequent membrane fusion, enabling viral entry. HA is a homotrimeric protein, with each monomer cleaved into HA1 and HA2 subunits. The globular head domain (mainly HA1) is responsible for receptor binding and is the primary target for neutralizing antibodies. The stem domain (mainly HA2) anchors the protein to the viral membrane and contains elements critical for fusion. Antigenic drift necessitates frequent updates to influenza vaccines.

Other names

HAH3N2 Hemagglutinin

NA inhibitors prevent release of new virions. Fusion inhibitors prevent viral entry by blocking fusion of the viral membrane with the host cell membrane. Monoclonal antibodies neutralize the virus by binding to HA and blocking receptor binding or membrane fusion.