PROBLEMS OF ISOLATION, IDENTIFICATION AND ANTIGENIC CHARACTERIZATION OF RECENT HUMAN A(H3N2) INFLUENZA VIRUSES

Area of Science:

• Virology
• Immunology
• Public Health

Background:

• Human influenza A (H3N2) viruses exhibit rapid evolution and adaptability.
• These viruses can evade host immune responses and alter receptor specificity.
• Over two decades, H3N2 viruses have lost hemagglutination ability in avian red blood cells and chicken embryos, impacting vaccine production.

Purpose of the Study:

• To highlight the challenges in antigenic analysis of influenza A (H3N2) viruses.
• To address the inadequacy of traditional methods for vaccine strain selection.
• To emphasize the urgent need for novel algorithms for H3N2 virus isolation and analysis.

Main Methods:

• Observation of viral evolution and adaptation.
• Analysis of viral propagation in cell cultures (MDCK) and chicken embryos.
• Assessment of antigenic properties using hemagglutination inhibition tests.
• Evaluation of mutations in viral neuraminidase.

Main Results:

• Influenza A (H3N2) viruses have lost the ability to agglutinate chicken and turkey red blood cells.
• Propagation in chicken embryos has significantly decreased.
• MDCK cell culture isolation selects for strains with altered glycosylation sites.
• Neuraminidase mutations in H3N2 strains distort antigenic analysis results.
• Traditional methods for antigenic characterization are becoming less informative.
• Discrepancies between vaccine and circulating H3N2 strains have been observed in recent years (2013-2016).

Conclusions:

• Traditional methods for characterizing influenza A (H3N2) viruses are becoming poorly informative.
• The selection of vaccine strains for H3N2 is increasingly erroneous due to viral evolution.
• New algorithms for isolating and antigenically analyzing H3N2 viruses are urgently required.