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Subnanometer-Resolution Structural Determination of Hemagglutinin from Cryo-Electron Tomography of Influenza Viruses
08:19

Subnanometer-Resolution Structural Determination of Hemagglutinin from Cryo-Electron Tomography of Influenza Viruses

Published on: November 7, 2025

STRUCTURE AND DEVELOPMENT OF VIRUSES AS OBSERVED IN THE ELECTRON MICROSCOPE : VII. INCOMPLETE INFLUENZA VIRUS

C Morgan1, K C Hsu, H M Rose

  • 1Departments of Microbiology and Medicine, College of Physicians and Surgeons, Columbia University, New York.

The Journal of Experimental Medicine
|October 30, 2009
PubMed

Insights

High concentrations of influenza virus (PR8 strain) in chicken embryos lead to the formation of incomplete viral particles. This occurs when concentrated inocula damage cells, interfering with viral differentiation but not cytoplasmic release.

Area of Science:

  • Virology
  • Cell Biology
  • Electron Microscopy

Background:

  • Influenza virus infections can alter host cell processes.
  • Understanding viral particle formation is crucial for virology research.

Purpose of the Study:

  • To investigate the effect of concentrated influenza virus inocula on chicken embryo cells.
  • To characterize the morphology and formation of viral particles under specific conditions.

Main Methods:

  • Infection of chicken embryos with influenza virus (PR8 strain) via the chorioallantoic route.
  • Electron microscopic examination of entodermal cells 24 hours post-infection.
  • Serial passage of the virus and assessment of infectivity-hemagglutinin ratio.

Main Results:

  • Observed membrane-bound cytoplasmic fragments released from entodermal cells.
  • Increased proportion of these fragments relative to typical viral particles after serial passage.
  • Reduced infectivity-hemagglutinin ratio (von Magnus effect) observed.
  • Fragments lacked internal components but possessed surface structures resembling the virus, containing viral antigen.

Conclusions:

  • Concentrated inocula may damage cells, disrupting normal viral differentiation.
  • Cellular damage can lead to the predominant formation of incomplete viral particles.
  • Accumulation of viral antigen at the cell surface may drive the formation of incomplete virus.

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