Influenza virus hemagglutinin, globular head domain (HA (globular head))

The globular head domain of influenza virus hemagglutinin (HA) is a substructure of the HA trimeric glycoprotein found on the surface of influenza virions. This domain is responsible for binding to sialic acid receptors on host cells, thereby determining host specificity and facilitating viral entry. It is also the primary target of neutralizing antibodies and the focal point for immune recognition, but mutations here lead to antigenic drift, allowing the virus to evade pre-existing immunity. Structurally, the head domain forms the upper portion of HA1 in the trimer, contains the receptor binding site, and is the target of most seasonal influenza vaccine responses. Because of its central role in infection and immunity, the HA globular head is a major therapeutic and vaccine target, though its high variability presents significant challenges for universal protection[2][3][4][5][7].

Other names

Influenza HA globular domainhemagglutinin head domainHA headhemagglutinin receptor binding domaininfluenza virus hemagglutinin head

Inhibition of receptor binding (by blocking the sialic acid binding site, thereby preventing viral attachment to host cells)[3][7] - Neutralization of virus by immune response (antibodies prevent virus entry and fusion)[3][4][7]