Influenza virus neuraminidase and internal proteins (NA/NP/M1)

This target refers to the combination of influenza virus neuraminidase (NA) and internal structural proteins, such as nucleoprotein (NP) and matrix protein (M1), which are the primary antigenic components of split-virion influenza vaccines. Neuraminidase is an essential viral enzyme (EC 3.2.1.18) that cleaves sialic acid on host cell surfaces to facilitate the release and spread of progeny virions (Shtyrya et al., 2009 [1]). The internal proteins, NP and M1, are highly conserved across influenza strains and serve as important targets for cross-reactive T-cell mediated immunity, which helps limit the severity of infection (Grant et al., 2013 [2]). In split-virion preparations, the virus is chemically disrupted to expose these internal antigens, providing a broader immunogenic profile than purified surface-antigen vaccines (Lambert and Fauci, 2010 [3]). Therapeutic agents known as neuraminidase inhibitors target the enzymatic activity of the neuraminidase component to treat active infections, while the entire protein complex is utilized in seasonal vaccines to elicit protective immune responses (McNicholl and McNicholl, 2001 [4]).

Other names

Split influenza virus antigensInfluenza split virion componentsNeuraminidase and internal viral proteinsDisrupted influenza virus antigensInfluenza virus NA, NP, and M1 proteins

Neuraminidase inhibitors competitively bind to the NA active site to prevent viral shedding (Gubareva et al., 2000 [5]), while the protein complex in split-virion vaccines acts as an immunogen to induce neutralizing antibodies against NA and activate T-cell responses against conserved internal proteins like NP and M1 (Lambert and Fauci, 2010 [3]).