Neutrophil extracellular traps are induced by Mycobacterium tuberculosis

Tuberculosis (Edinb). 2009 Jan;89(1):29-37. doi: 10.1016/ Epub 2008 Dec 3.


Due to the intracellular nature of mycobacterial infections, little attention has been paid to the possible extracellular role that neutrophils might play in tuberculosis. The recent discovery of neutrophil extracellular traps (NETs), composed of DNA and antimicrobial proteins,(1) introduces a new perspective to our understanding of the mechanism used by the innate immune system to contain and kill microorganisms. In this study, we tested in vitro whether Mycobacterium tuberculosis, an intracellular pathogen, can induce NETs formation and if this newly discovered mechanism is involved in a control response during mycobacterial infection. We found that two different genotypes of M. tuberculosis exerted, in vitro, a cytotoxic effect and induced subcellular changes on infected neutrophils, leading to NETs formation in a time dependent manner. NETs trapped mycobacteria but were unable to kill them. NETs formation induced by M. tuberculosis could help understand the early stages of mycobacterial pathogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents
  • DNA / analysis
  • Extracellular Space / immunology*
  • Fluorescent Dyes
  • Genes, Bacterial
  • Genotype
  • Humans
  • Immunity, Innate
  • Microscopy, Electron, Scanning
  • Microscopy, Electron, Transmission
  • Mycobacterium tuberculosis / genetics
  • Mycobacterium tuberculosis / pathogenicity*
  • Mycobacterium tuberculosis / ultrastructure
  • Neutrophils / microbiology
  • Neutrophils / physiology*
  • Neutrophils / ultrastructure
  • Phagocytosis
  • Staining and Labeling
  • Tuberculosis / genetics
  • Tuberculosis / immunology*
  • Tuberculosis / pathology
  • Virulence Factors / genetics
  • Virulence Factors / immunology


  • Anti-Bacterial Agents
  • Fluorescent Dyes
  • Virulence Factors
  • DNA