Hemagglutinin (HA) (Influenza A virus H2N3 strain) (HA)

Hemagglutinin (HA) is the primary surface glycoprotein of the Influenza A virus H2N3 strain, playing a dual role in viral attachment and membrane fusion. It functions by recognizing and binding to sialic acid receptors on the host cell surface, which triggers receptor-mediated endocytosis (Source: UniProt, A0A0U1WJB1). Following internalization, the acidic environment of the endosome induces a significant conformational change in the HA protein, facilitating the fusion of the viral envelope with the host endosomal membrane (Source: PubMed, PMID: 18063711). The H2N3 subtype is of particular concern to public health because it emerged as a reassortant virus in swine with avian-origin segments, posing a zoonotic threat to humans who lack pre-existing immunity to H2-type viruses (Source: Nature Medicine, doi:10.1038/nm1677). As the major antigen on the viral surface, HA is the primary target for neutralizing antibodies and the central component of seasonal and pandemic vaccine formulations (Source: CDC, "Influenza Virus Genome"). Therapeutic strategies targeting HA include small-molecule inhibitors like Umifenovir, which prevents the fusion process, and monoclonal antibodies that block receptor binding or stabilize the prefusion state (Source: PubChem, CID 131411). Development of drugs against H2N3 HA is critical for pandemic preparedness, as this target is essential for the initiation of the viral infection cycle (Source: NIH, "Influenza Antiviral Drug Development").

Other names

H2 hemagglutininHA proteinSurface glycoproteinHemagglutinin HA1/HA2Influenza A virus H2N3 hemagglutinin

Inhibition of viral attachment to host cell sialic acid receptors and prevention of pH-induced conformational changes required for membrane fusion.