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Molecular characterization of a new hemagglutinin, subtype H14, of influenza A virus

Y Kawaoka1, S Yamnikova, T M Chambers

  • 1St. Jude Children's Research Hospital, Department of Virology and Molecular Biology, Memphis, Tennessee 38101.

Virology
|December 1, 1990
PubMed

Insights

Two new influenza A virus subtypes, designated H14, were discovered in mallard ducks. These viruses possess unique hemagglutinin (HA) proteins and may represent a recently diverged lineage, unlike older subtypes H8 and H12.

Area of Science:

  • Virology
  • Molecular Biology
  • Immunology

Background:

  • Influenza A viruses are classified into subtypes based on their hemagglutinin (HA) and neuraminidase (NA) proteins.
  • Existing HA subtypes are defined by antigenic and genetic differences, with significant amino acid divergence often indicating a new subtype.
  • Avian influenza viruses are a diverse reservoir for novel influenza strains.

Purpose of the Study:

  • To characterize two newly isolated influenza A viruses from mallard ducks.
  • To determine if these viruses represent a previously unrecognized HA subtype.
  • To investigate the evolutionary relationship and unique features of the novel HA subtype.

Main Methods:

  • Antigenic analysis using hemagglutination inhibition and double immunodiffusion tests.
  • Nucleotide and amino acid sequence analysis of HA genes.
  • Experimental infection of domestic poultry and ferrets.
  • Phylogenetic analysis of HA gene sequences.

Main Results:

  • Two influenza A viruses with distinct HA properties were isolated from mallard ducks.
  • Antigenic and sequence analyses confirmed these viruses belong to a new HA subtype, designated H14.
  • H14 HA proteins exhibit unique characteristics, including lysine at the HA1/HA2 cleavage site, and differ significantly at the amino acid level from other subtypes.
  • The H14 virus was found to be avirulent in domestic poultry and ferrets.
  • Phylogenetic analysis suggests H14 is a recently diverged lineage, while H8 and H12 are ancient and potentially disappearing subtypes.

Conclusions:

  • The discovery of H14 represents a new HA subtype of influenza A virus.
  • The unique molecular features of H14 HA may have implications for viral evolution and classification.
  • The findings contribute to understanding the diversity and evolution of influenza A viruses in natural reservoirs.

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