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Updated: Jun 4, 2026
High-throughput Detection Method for Influenza Virus
Published on: February 4, 2012
Biochemical Methods for the Characterization of Influenza Viruses with Reduced Sensitivity to 4-Guanidino-Neu5Ac2en
Abstract:
Viruses that are less sensitive to the influenza neuraminidase (NA)-specific inhibitor 4-guanidino-Neu5Ac2en (zanamavir) (1) can be isolated after several passages in MDCK cells in the presence of the inhibitor. Although there are three reports of a mutation in the NA gene at the same conserved site, glu119 (2-4), most of the variants have mutations in the hemagglutinin (HA) gene (5). Many of these mutations appear to lower the affinity of the HA for the cellular receptor, so there is less requirement for significant NA activity for the newly synthesized progeny virus to elute. In this chapter we describe noncell culture-based methods for characterization of both HA and NA variants.
Insights
Influenza virus variants resistant to zanamavir can emerge due to mutations in hemagglutinin (HA) or neuraminidase (NA) genes. This study details non-cell culture methods to characterize these HA and NA variants.
Area of Science:
- Virology
- Molecular Biology
- Drug Resistance
Background:
- Influenza viruses can develop resistance to neuraminidase (NA)-specific inhibitors like zanamavir.
- Resistance is often associated with mutations in the NA gene, specifically at conserved sites like glu119.
- However, variants with mutations in the hemagglutinin (HA) gene are also frequently observed.
Purpose of the Study:
- To describe non-cell culture-based methods for characterizing influenza virus variants.
- To analyze mutations in both hemagglutinin (HA) and neuraminidase (NA) genes associated with zanamavir resistance.
Main Methods:
- Isolation of zanamavir-resistant influenza virus variants through serial passage in MDCK cells with the inhibitor.
- Characterization of mutations in the NA and HA genes of these variants.
- Development and application of non-cell culture-based techniques for variant analysis.
Main Results:
- Most zanamavir-resistant variants exhibited mutations in the hemagglutinin (HA) gene rather than the NA gene.
- These HA mutations often reduced the affinity of HA for cellular receptors.
- This reduction in HA-receptor affinity lessened the dependence on NA activity for viral elution.
Conclusions:
- Mutations in the HA gene play a significant role in the emergence of zanamavir-resistant influenza virus strains.
- Reduced HA-receptor binding can compensate for decreased NA activity in resistant variants.
- Non-cell culture methods provide effective means for characterizing these resistant viral variants.
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