Influenza virus hemagglutinin and neuraminidase protein complexes (HA/NA complexes)

Heterologous influenza viral proteins in vaccine formulation – intermolecular protein complexes refer to the antigenic components of multivalent vaccines where proteins from different influenza strains are physically associated (CDC, 2023). These complexes primarily consist of Hemagglutinin (HA) and Neuraminidase (NA), the major surface glycoproteins of the influenza virus (UniProt, 2024). In nature, HA mediates viral binding to host cell sialic acid receptors and subsequent membrane fusion, while NA facilitates the release of new viral particles (PubMed, 2021). In a vaccine context, these proteins are engineered to form stable intermolecular complexes, such as nanoparticles or virus-like particles, to improve their immunogenicity (Shinde et al., 2020). By incorporating heterologous proteins from various influenza A and B strains into a single complex, the vaccine can present a broader range of epitopes to the immune system (WHO, 2024). This approach is designed to elicit a more robust and cross-reactive antibody response compared to traditional split-virus vaccines. These complexes serve as the primary target for the host's immune system to generate neutralizing antibodies, which are the main correlates of protection against infection. Clinical applications of this technology include recombinant vaccines like NanoFlu, which aim to provide enhanced protection for older adults against seasonal influenza.

Other names

Multivalent influenza antigensHeterologous HA/NA complexesRecombinant influenza nanoparticlesInfluenza virus-like particles (VLPs)Heterologous influenza viral proteins in vaccine formulation – intermolecular protein complexes

Active immunization; induction of neutralizing antibodies against viral surface glycoproteins to prevent viral attachment and release.