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A Miniaturized Glycan Microarray Assay for Assessing Avidity and Specificity of Influenza A Virus Hemagglutinins
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Intermediates in influenza virus PR/8 haemagglutinin-induced membrane fusion

C C Pak1, M Krumbiegel, R Blumenthal

  • 1Section of Membrane Structure and Function, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.

The Journal of General Virology
|February 1, 1994
PubMed

Insights

Influenza A virus strain PR/8 exhibits a low-temperature intermediate in membrane fusion, involving haemagglutinin conformational changes and fusion peptide exposure, unlike strain X:31. This reveals insights into viral fusion mechanisms.

Area of Science:

  • Virology
  • Molecular Biology
  • Biochemistry

Background:

  • Influenza A virus (IAV) fusion with host cells is mediated by haemagglutinin (HA).
  • Previous studies indicated differential fusion capabilities between IAV strains X:31 and PR/8 at low temperatures and pH.

Purpose of the Study:

  • To compare the fusion kinetics of IAV strains X:31 and PR/8 with erythrocyte ghosts.
  • To correlate fusion kinetics with HA conformational changes.
  • To investigate the underlying mechanisms for PR/8's lack of cold fusion.

Main Methods:

  • Fusion assays using erythrocyte ghosts.
  • Analysis of HA conformational changes via proteinase K digestion.
  • Liposome binding assays.
  • Immunoprecipitation with conformation-specific antibodies.

Main Results:

  • IAV strain PR/8 showed no fusion with erythrocyte ghosts at 4°C, pH 5, unlike strain X:31.
  • PR/8 HA underwent low pH-induced conformational changes, including fusion peptide exposure, at 4°C, pH 5.
  • Despite fusion peptide exposure, PR/8 HA showed minimal interaction with the target membrane at low temperatures.

Conclusions:

  • IAV strain PR/8 exhibits a low-temperature intermediate in membrane fusion.
  • This intermediate involves HA conformational changes and fusion peptide exposure but limited target membrane interaction.
  • The findings provide insights into the temperature-dependent regulation of influenza virus membrane fusion.

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