M. tuberculosis and M. leprae translocate from the phagolysosome to the cytosol in myeloid cells

Cell. 2007 Jun 29;129(7):1287-98. doi: 10.1016/j.cell.2007.05.059.

Abstract

M. tuberculosis and M. leprae are considered to be prototypical intracellular pathogens that have evolved strategies to enable growth in the intracellular phagosomes. In contrast, we show that lysosomes rapidly fuse with the virulent M. tuberculosis- and M. leprae-containing phagosomes of human monocyte-derived dendritic cells and macrophages. After 2 days, M. tuberculosis progressively translocates from phagolysosomes into the cytosol in nonapoptotic cells. Cytosolic entry is also observed for M. leprae but not for vaccine strains such as M. bovis BCG or in heat-killed mycobacteria and is dependent upon secretion of the mycobacterial gene products CFP-10 and ESAT-6. The cytosolic bacterial localization and replication are pathogenic features of virulent mycobacteria, causing significant cell death within a week. This may also reveal a mechanism for MHC-based antigen presentation that is lacking in current vaccine strains.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigen Presentation / physiology
  • Biomarkers / metabolism
  • Cell Compartmentation / physiology
  • Cell Death / physiology
  • Cell Division / physiology
  • Cell Movement / physiology
  • Cell Proliferation
  • Cells, Cultured
  • Cytosol / physiology*
  • Cytosol / ultrastructure
  • Gene Expression Regulation, Bacterial / physiology
  • Host-Parasite Interactions / physiology
  • Humans
  • Immunohistochemistry
  • Intracellular Membranes / physiology
  • Intracellular Membranes / ultrastructure
  • Lysosomes / physiology*
  • Lysosomes / ultrastructure
  • Membrane Proteins / metabolism
  • Microscopy, Electron, Transmission
  • Mycobacterium / genetics
  • Mycobacterium / physiology*
  • Mycobacterium / ultrastructure
  • Mycobacterium leprae / genetics
  • Mycobacterium leprae / physiology
  • Mycobacterium leprae / ultrastructure
  • Mycobacterium tuberculosis / genetics
  • Mycobacterium tuberculosis / physiology
  • Mycobacterium tuberculosis / ultrastructure
  • Myeloid Cells / microbiology*
  • Myeloid Cells / physiology
  • Myeloid Cells / ultrastructure
  • Phagosomes / physiology*
  • Phagosomes / ultrastructure

Substances

  • Biomarkers
  • Membrane Proteins