Influenza B Virus Hemagglutinin Victoria Lineage Antigen (HA (Victoria Lineage))

The hemagglutinin (HA) antigen of the Influenza B virus Victoria lineage is a surface glycoprotein critical for viral entry into host cells. It mediates binding to sialic acid-containing receptors on the host cell surface and facilitates membrane fusion, allowing viral RNA to enter the cell. The HA protein is also the primary target for neutralizing antibodies and plays a central role in immune recognition and vaccine design. Immunity against one lineage does not confer strong protection against the other due to significant antigenic divergence. Both lineages induce robust interferon responses upon infection of human nasal epithelial cells; however, B/Victoria strains tend to elicit stronger interferon-related signaling than Yamagata strains. The World Health Organization recommends inclusion of both B/Victoria-lineage antigens alongside other influenza strains in seasonal quadrivalent vaccines due to their co-circulation globally.

Other names

B/Victoria lineage hemagglutininInfluenza B HA (Victoria)Victoria lineage HAHemagglutinin (Influenza B Victoria)

Vaccines induce neutralizing antibodies that block HA-mediated viral attachment and entry. Monoclonal antibodies directly bind to HA, preventing receptor binding and/or membrane fusion.