Influenza A and B virus Hemagglutinin and Neuraminidase (HA/NA)

Influenza A and B virus Hemagglutinin (HA) and Neuraminidase (NA) are the primary surface glycoproteins of the influenza virus and serve as critical targets for both prophylactic and therapeutic interventions (UniProt: P03435, P03468). Hemagglutinin is responsible for viral attachment to host cell sialic acid receptors and subsequent membrane fusion, while Neuraminidase facilitates the release of newly formed viral particles by cleaving sialic acid residues (PubMed: 22226355, NCBI: NBK542264). Because these proteins are essential for the viral life cycle, they are the main components of seasonal influenza vaccines, which aim to elicit neutralizing antibodies (CDC, 2023). Additionally, Neuraminidase is the specific target of several antiviral drugs, such as oseltamivir and zanamivir, which prevent the spread of infection within the respiratory tract (PubChem: CID 65028). The high rate of mutation in these proteins, known as antigenic drift, necessitates the frequent updating of vaccines and monitoring for drug resistance (WHO, 2024). Understanding the structural and functional roles of HA and NA is vital for developing broad-spectrum universal vaccines and more effective antiviral therapies.

Other names

HANASialidaseHemagglutininNeuraminidaseInfluenza surface antigensInfluenza A and B surface glycoproteins

Neuraminidase inhibitors (e.g., oseltamivir) block the enzymatic activity of NA, preventing the release of new viral particles from the host cell (NCBI: NBK542264). Hemagglutinin-targeted interventions, such as vaccine-induced antibodies or fusion inhibitors (e.g., umifenovir), prevent the virus from attaching to or entering host cells (PubMed: 22226355).