Influenza B virus (Victoria lineage) surface antigen (B/Victoria surface antigen)

The Influenza B Victoria lineage surface antigen is composed of two primary glycoproteins, Hemagglutinin (HA) and Neuraminidase (NA), which are expressed on the viral envelope. Hemagglutinin is responsible for binding the virus to sialic acid receptors on host respiratory cells and facilitating membrane fusion for viral entry [1][4]. Neuraminidase is an enzyme that cleaves these sialic acid linkages to allow the release of newly formed virions from the host cell surface, enabling the spread of infection [2][3]. As one of the two major lineages of Influenza B viruses circulating globally, the Victoria lineage is a critical component of seasonal quadrivalent influenza vaccines designed to elicit protective neutralizing antibodies [5][7]. Pharmacologically, the NA component is the direct target of neuraminidase inhibitors such as oseltamivir and zanamivir, which halt the viral life cycle by preventing egress [2][9]. The Victoria lineage is subject to frequent antigenic drift, characterized by mutations and deletions (such as the 162-164 deletions in the HA head) that can lead to vaccine mismatch and necessitate regular surveillance and strain updates [10][11].

Other names

Influenza B/Victoria lineage surface glycoproteinsVictoria lineage hemagglutinin and neuraminidaseB/Victoria surface proteinsInfluenza B/Victoria/2/87-like surface antigen

Neuraminidase inhibitors bind to the active site of the NA enzyme to prevent the cleavage of sialic acid, thereby trapping progeny virions on the host cell membrane. Vaccine-induced antibodies bind primarily to the HA protein, sterically hindering viral attachment and fusion with host cell receptors.