Influenza A Virus Hemagglutinin (H5) (H5 HA)

Influenza A virus hemagglutinin subtype 5 (H5) is an essential glycoprotein mediating both attachment to host cells via sialic acid recognition and subsequent entry through membrane fusion. Its molecular features underlie both its role in pathogenesis and immune evasion/adaptation across species barriers. The cleavage site sequence is a key determinant of pathogenicity, and mutations affecting receptor binding affinity (e.g., to human-type receptors) can increase zoonotic potential. It is a major target for neutralizing antibodies, making it a key component of influenza vaccines.

Other names

H5 hemagglutininHA (H5)H5N1 hemagglutinin

Attachment to sialic acid receptors and subsequent membrane fusion. Targeted indirectly by neuraminidase inhibitors that prevent the release of newly formed virions, thereby limiting the spread of infection.