Influenza virus surface antigens (Hemagglutinin and Neuraminidase) (HA/NA)

Influenza virus surface antigens, primarily Hemagglutinin (HA) and Neuraminidase (NA), are the critical molecular targets for the humoral immune response elicited by infection or vaccination (Nature Reviews Microbiology, 2018). Hemagglutinin is a viral glycoprotein that mediates binding to host cell sialic acid receptors and subsequent membrane fusion, while Neuraminidase is an enzyme that facilitates the release of progeny virions by cleaving those same receptors (UniProt, P03437; StatPearls, 2023). In quadrivalent vaccines, these antigens are derived from four specific strains: two Influenza A subtypes (H1N1 and H3N2) and two Influenza B lineages (Victoria and Yamagata) (CDC, 2023). The humoral response involves the production of neutralizing antibodies that bind to these proteins to block the viral life cycle. Therapeutic strategies include vaccines to prime the immune system and antiviral drugs, such as Oseltamivir, which directly inhibit Neuraminidase activity (PubMed, PMC6113657). Monitoring this response via biomarkers like hemagglutination inhibition titers is essential for evaluating vaccine efficacy and addressing the challenges of viral evolution (Vaccines, 2020).

Other names

Influenza surface glycoproteinsHemagglutininNeuraminidaseFlu antigensHANA

Vaccines introduce viral surface antigens to stimulate B-cells to produce neutralizing antibodies that block Hemagglutinin-mediated entry or Neuraminidase-mediated release; antiviral drugs like Oseltamivir competitively inhibit the Neuraminidase enzyme to prevent viral spread (Nature Reviews Microbiology, 2018).