Influenza virus envelope glycoproteins (HA/NA)

Influenza virus envelope glycoproteins, primarily hemagglutinin (HA) and neuraminidase (NA), are the major surface antigens of the influenza virus and play indispensable roles in the viral infection cycle [1, 2]. Hemagglutinin facilitates viral entry by binding to sialic acid receptors on host cells and mediating the fusion of the viral and endosomal membranes [3, 5]. Neuraminidase is an enzyme that cleaves terminal sialic acid residues from glycoproteins, which is essential for the release of progeny virions from infected cells and preventing viral aggregation [2, 3]. These glycoproteins are the primary targets for neutralizing antibodies induced by natural infection or vaccination, and their high rate of mutation leads to antigenic drift, requiring annual vaccine updates [3]. Therapeutically, neuraminidase inhibitors like oseltamivir and zanamivir are widely used to treat influenza by blocking viral spread within the host [4]. Emerging therapies also target the conserved regions of the hemagglutinin stalk to provide broader protection against multiple influenza strains [5]. Additionally, the M2 ion channel protein, while not a glycoprotein, is often associated with these surface proteins and was a historical target for adamantane-class drugs [3]. Understanding the structure and function of these glycoproteins is vital for pandemic preparedness and the development of universal influenza vaccines [1, 3].

Other names

HemagglutininNeuraminidaseHANAInfluenza surface glycoproteinsViral envelope proteins

Neuraminidase inhibitors block the enzymatic activity of NA to prevent the release of new virions; Hemagglutinin inhibitors prevent viral attachment or membrane fusion.