Hemagglutinin (H) Protein (HA)

Hemagglutinin (HA) is a major surface glycoprotein of the Influenza A H1N1 virus. It is a homotrimeric integral membrane glycoprotein essential for viral entry into host cells, functioning as both an attachment factor (binding to sialic acid receptors) and a membrane fusion protein. Cleavage of the HA0 precursor into HA1 and HA2 subunits is required for activation. HA is a primary target for neutralizing antibodies, and mutations in HA can lead to immune escape and the emergence of new influenza strains.

Other names

HemagglutininInfluenza HemagglutininH1N1 Hemagglutinin

Neutralizing antibodies bind to HA and prevent receptor binding or membrane fusion; NA inhibitors prevent release of newly formed virions, reducing selection pressure on HA.