Influenza A virus (H7N9) hemagglutinin (HA) (H7N9 HA)

The target refers to the induction of a protective adaptive immune response against the H7N9 avian influenza virus, specifically targeting the viral hemagglutinin (HA) protein. Hemagglutinin is a critical surface glycoprotein that mediates viral entry by binding to sialic acid receptors on host respiratory cells (UniProt P0C6B5). In the context of vaccination, the HA protein serves as the primary antigen for the production of neutralizing antibodies. The AS03 adjuvant, an oil-in-water emulsion containing alpha-tocopherol and squalene, is used to enhance the immunogenicity of the HA antigen (Garçon et al., 2012). AS03 works by stimulating a local innate immune response, which increases the recruitment and activation of antigen-presenting cells to the draining lymph nodes. This results in a more robust and broader adaptive immune response, including higher titers of hemagglutination inhibition antibodies and improved T-cell activation (Jackson et al., 2015). This strategy is vital for pandemic preparedness against highly pathogenic avian influenza strains that exhibit low intrinsic immunogenicity.

Other names

H7N9 HemagglutininHA antigenAS03-adjuvanted H7N9 vaccineAvian influenza A (H7N9) surface glycoprotein

The H7N9 hemagglutinin (HA) protein acts as the primary antigen that is recognized by the adaptive immune system to produce neutralizing antibodies. The AS03 adjuvant, an oil-in-water emulsion containing alpha-tocopherol and squalene, enhances this process by creating a transient immunocompetent environment at the injection site, increasing the recruitment of antigen-presenting cells and the magnitude of the B-cell and T-cell response (Garçon et al., 2012; Jackson et al., 2015).