Human phagocytes lack the ability to kill Mycobacterium gordonae, a non-pathogenic mycobacteria

Immunol Lett. 2008 Feb 15;116(1):72-8. doi: 10.1016/j.imlet.2007.11.010. Epub 2007 Dec 7.


Non-pathogenic mycobacteria, like Mycobacterium gordonae, are rarely associated to disease. The analysis of the mechanisms which are successful against them in the human host may provide useful information to understand why they fail against the pathogenic M. tuberculosis. We have developed an infection model to test the ability of human phagocytes to kill two strains of M. gordonae, HL184G and an attenuated variety, HL184Gat. As controls we included a strain of M. tuberculosis (HL186T) and another one of L. pneumophila (ATCC13151). We observed that human phagocytes lack the intrinsic ability to eliminate either M. gordonae or M. tuberculosis, but they can kill the attenuated strain. We found a relationship between pathogenicity and the pattern of cytokine production. Thus, both the pathogenic M. tuberculosis and Legionella pneumophila, but not the non-pathogenic M. gordonae, induced the production of significantly different levels of IL-1beta, IL-6 and TNF-alpha in monocytes and IL-8 in neutrophils. Although both monocytes and neutrophils killed HL184Gat, but not HL184G, the patterns of cytokine production induced by either strain were identical. Addition of INF-gamma and/or TNF-alpha did not enhance the antimycobacterial activity of phagocytes.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Culture Techniques
  • Colony Count, Microbial
  • Cytokines / immunology*
  • Cytokines / metabolism
  • Gene Expression Regulation, Bacterial / immunology
  • Host-Pathogen Interactions
  • Humans
  • Inflammation Mediators / immunology
  • Inflammation Mediators / metabolism
  • Killer Cells, Natural / immunology*
  • Killer Cells, Natural / microbiology
  • Legionella pneumophila / immunology
  • Legionella pneumophila / pathogenicity
  • Microbial Viability
  • Mycobacterium Infections / immunology*
  • Mycobacterium Infections / pathology
  • Mycobacterium tuberculosis / immunology*
  • Mycobacterium tuberculosis / pathogenicity
  • Nontuberculous Mycobacteria / immunology*
  • Nontuberculous Mycobacteria / pathogenicity
  • Phagocytes / immunology*
  • Phagocytes / microbiology
  • Tuberculosis / immunology*
  • Tuberculosis / pathology


  • Cytokines
  • Inflammation Mediators