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Virulence associated ingestion of Legionella pneumophila by HeLa cells

L A Dreyfus1

  • 1Department of Microbiology, University of Texas Medical Branch, Galveston 77550.

Microbial Pathogenesis
|July 1, 1987
PubMed

Insights

Virulent Legionella pneumophila efficiently invade host cells, while avirulent strains do not. Restoring virulence in Legionella pneumophila also restored its ability to invade HeLa cells.

Area of Science:

  • Microbiology
  • Cell Biology
  • Infectious Diseases

Background:

  • Legionella pneumophila is an intracellular bacterium responsible for Legionnaires' disease.
  • Understanding the mechanisms of bacterial invasion into host cells is crucial for developing effective treatments.

Purpose of the Study:

  • To investigate the role of bacterial virulence in the invasion of non-professional phagocytes by Legionella pneumophila.
  • To compare the invasion efficiency of virulent and avirulent strains of L. pneumophila in HeLa cells.

Main Methods:

  • Utilized HeLa cell monolayers as a model system for studying host cell invasion.
  • Compared the invasion efficiency of virulent L. pneumophila strains with isogenic avirulent isolates.
  • Assessed bacterial association with HeLa cells to differentiate between entry and adherence.

Main Results:

  • Virulent L. pneumophila strains demonstrated efficient entry into HeLa cells.
  • Isogenic avirulent isolates were approximately 1000-fold less efficient at cellular entry.
  • Restoration of virulence through animal passage in avirulent strains correlated with a return to parental levels of HeLa cell invasion.
  • Reduced invasion by avirulent strains was not due to decreased bacterial association with the cell monolayer.

Conclusions:

  • Bacterial virulence is a key factor determining the invasion of non-professional phagocytes by Legionella pneumophila.
  • The ability of L. pneumophila to be ingested by non-professional phagocytes is a virulence-directed property.

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