Influenza virus hemagglutinin globular head domain (HA1)

The influenza virus hemagglutinin (HA) globular head domain is the membrane-distal portion of the HA protein, primarily composed of the HA1 subunit [2, 13]. It contains the receptor-binding site (RBS) that recognizes sialic acid on host cell surfaces, facilitating viral attachment and subsequent entry [3, 7]. As the most immunodominant part of the virus, the globular head is the primary target for neutralizing antibodies elicited by seasonal influenza vaccines [15, 16]. However, this domain is highly plastic and undergoes frequent mutations, a process known as antigenic drift, which allows the virus to evade host immunity and necessitates annual vaccine updates [1, 15]. Therapeutic strategies targeting the head domain include traditional vaccines, monoclonal antibodies that block the RBS, and emerging approaches targeting conserved regions like the trimer interface [12, 17].

Other names

HA1 subunitHA headGlobular head domainReceptor binding domainGH domainHemagglutinin head

Blocking the receptor binding site (RBS) to prevent viral attachment to host cell sialic acid receptors; inhibiting viral egress; or destabilizing the trimer interface.