Influenza B virus Victoria lineage neuraminidase (NA)

Influenza B/Victoria neuraminidase (NA) is a critical surface glycoprotein and enzyme found on the Victoria lineage of influenza B viruses. It functions as an exosialidase (EC 3.2.1.18), specifically cleaving terminal sialic acid residues from glycoproteins and glycolipids on the host cell surface and the viral envelope. This enzymatic activity is essential for the release of progeny virions from infected cells, preventing their aggregation and facilitating the spread of the virus through the respiratory tract by degrading sialic acid-containing mucins. As a primary target for antiviral therapy, NA is inhibited by drugs such as oseltamivir, zanamivir, and peramivir, which mimic the sialic acid substrate to block the enzyme's active site. While influenza B viruses generally show lower susceptibility to certain neuraminidase inhibitors compared to influenza A, the Victoria lineage remains a major focus for seasonal vaccine development and antiviral monitoring due to its continued global circulation. Resistance-conferring mutations, such as H273Y or D197E, are monitored globally to ensure the continued efficacy of these therapeutic interventions. The protein's role in viral fitness and its antigenic evolution make it a key component in the design of next-generation universal influenza vaccines.

Other names

NeuraminidaseSialidaseB/Victoria NAInfluenza B Victoria lineage NANA protein

Neuraminidase inhibitors (NAIs) are sialic acid analogs that competitively bind to the highly conserved active site of the viral neuraminidase enzyme. By occupying this site, the drugs prevent the enzyme from cleaving terminal sialic acid residues on host cell surfaces and viral envelopes. This inhibition results in the entrapment of newly synthesized virions at the host cell membrane, leading to viral aggregation and preventing the release and subsequent spread of progeny viruses to uninfected cells.