Hemagglutinin protein of H5N1 influenza virus (HA (H5N1))

The **hemagglutinin protein of H5N1 influenza virus** (HA) is a trimeric viral surface glycoprotein essential for the virus's ability to infect host cells. It is responsible for binding to host cell sialic acid receptors via its HA1 domain, allowing viral attachment and entry, and mediates the fusion of the viral envelope with the endosomal membrane through conformational changes in its HA2 domain in response to low pH. HA is the primary target of neutralizing antibodies and the main antigen in influenza vaccines. Mutations in HA influence pathogenicity, host range, and immune escape. The H5 subtype, in particular, is associated with highly pathogenic avian influenza and poses a significant zoonotic and pandemic risk[1][3][5][7].

Other names

Hemagglutinin (influenza)HAInfluenza A virus hemagglutininH5 hemagglutininH5N1 HA

Inhibitors and antibodies block receptor binding or membrane fusion, preventing viral entry Vaccines induce neutralizing antibodies against HA to block infection