Germination of Bacillus anthracis spores within alveolar macrophages

Mol Microbiol. 1999 Jan;31(1):9-17. doi: 10.1046/j.1365-2958.1999.01137.x.


The fatal character of the infection caused by inhalation of Bacillus anthracis spores results from a complex pathogenic cycle involving the synthesis of toxins by the bacterium. We have shown using immunofluorescent staining, confocal scanning laser microscopy and image cytometry analysis that the alveolar macrophage was the primary site of B. anthracis germination in a murine inhalation infection model. Bacillus anthracis germinated inside murine macrophage-like RAW264.7 cells and murine alveolar macrophages. Germination occurred in vesicles derived from the phagosomal compartment. We have also demonstrated that the toxin genes and their trans-activator, AtxA, were expressed within the macrophages after germination.

MeSH terms

  • Animals
  • Antigens, Bacterial*
  • Bacillus anthracis / physiology*
  • Bacterial Toxins / genetics
  • Cell Line
  • Fluorescent Dyes
  • Gene Expression Regulation, Bacterial
  • Macrophages, Alveolar / cytology
  • Macrophages, Alveolar / microbiology*
  • Mice
  • Rabbits
  • Rhodamines
  • Spores, Bacterial
  • Subcellular Fractions
  • Trans-Activators / genetics


  • Antigens, Bacterial
  • Bacterial Toxins
  • Fluorescent Dyes
  • Rhodamines
  • Trans-Activators
  • anthrax toxin