Influenza A virus hemagglutinin H7 subtype (H7 HA)

Hemagglutinin (HA) H7 is a subtype of the primary surface glycoprotein of Influenza A virus, predominantly found in avian-origin strains such as H7N9, H7N7, and H7N3, which have demonstrated the potential for zoonotic transmission to humans. It exists as a homotrimer on the viral envelope, where each monomer is composed of the HA1 subunit, responsible for binding to host cell sialic acid receptors, and the HA2 subunit, which mediates the fusion of the viral and endosomal membranes. The H7 subtype is a critical determinant of viral pathogenicity; for instance, the presence of a polybasic cleavage site in certain H7 strains allows for systemic infection beyond the respiratory tract. As the major surface antigen, H7 HA is the primary target for neutralizing antibodies and is the central focus for the development of vaccines and novel antiviral therapies, including fusion inhibitors and broadly neutralizing monoclonal antibodies. Drugs targeting this protein aim to block the initial stages of the viral life cycle, either by preventing attachment to the host cell or by inhibiting the pH-dependent conformational change required for membrane fusion.

Other names

H7 hemagglutininH7 HAHemagglutinin H7H7 glycoproteinInfluenza A H7

Inhibition of viral entry by blocking the receptor binding site on the HA1 subunit or stabilizing the prefusion conformation of the HA2 subunit to prevent pH-triggered membrane fusion.