Influenza A virus H5 hemagglutinin HA1 subunit (H5 HA1)

The H5 hemagglutinin HA1 oligomeric globular domain is the major surface glycoprotein component of the Influenza A virus H5 subtype, such as H5N1 (UniProt: P03452). It functions as a lectin, specifically binding to alpha-2,3-linked sialic acid receptors on host cells to initiate viral entry (PubMed: 16543414). The HA1 subunit forms the "head" of the spike-like HA trimer, housing the receptor-binding site (RBS) which is the primary target for neutralizing antibodies (PubMed: 23133205). Due to high selective pressure from the host immune system, this domain frequently accumulates mutations, a process known as antigenic drift, which necessitates frequent updates to vaccine strains (CDC: Antigenic Drift). Therapeutic strategies targeting this domain include prepandemic vaccines like Audenz and experimental monoclonal antibodies designed to block viral attachment (FDA: Audenz). Understanding the oligomeric structure of the HA1 globular domain is vital for developing broadly neutralizing therapies against avian influenza viruses with pandemic potential (PubMed: 29439209). This domain is often produced recombinantly in oligomeric forms to mimic the native viral state for vaccine efficacy (PubMed: 20141917).

Other names

H5 globular head domainH5 HA1 domainHemagglutinin HA1 subunitH5N1 HA1

Neutralization of viral infection by blocking the receptor-binding site on the HA1 globular domain, preventing the virus from attaching to host cell sialic acid receptors (PubMed: 23133205).