Influenza B virus hemagglutinin (HA0) (HA0)

Influenza B virus hemagglutinin (HA) is a major surface glycoprotein and a critical mediator of viral infectivity, synthesized as a precursor polypeptide called HA0. For the virus to become infectious, HA0 must undergo proteolytic cleavage by host cell proteases into two subunits, HA1 and HA2, which are essential for receptor binding and membrane fusion, respectively. The HA1 subunit recognizes and binds to sialic acid-containing receptors on the host cell surface to initiate endocytosis, while the HA2 subunit undergoes a dramatic conformational change at low pH to fuse the viral and endosomal membranes. As the primary target of the host's neutralizing antibody response, HA0 is the central antigen in both inactivated and live-attenuated influenza vaccines. Modern drug development efforts target conserved regions of the HA0 stem or the cleavage site to create universal vaccines and broad-spectrum antivirals that can bypass the challenges of antigenic drift.

Other names

Hemagglutinin precursorInfluenza B HAHA0 proteinHA0 peptideHemagglutininInfluenza B virus HA0

Inhibition of viral entry by blocking the attachment of the HA1 subunit to host sialic acid receptors or by preventing the proteolytic cleavage of HA0 into its functional subunits, thereby inhibiting the pH-dependent membrane fusion mediated by the HA2 subunit.