Mycobacterium vaccae induces a population of pulmonary CD11c+ cells with regulatory potential in allergic mice

Eur J Immunol. 2004 Mar;34(3):631-638. doi: 10.1002/eji.200324659.


The hygiene hypothesis proposes that common, harmless microorganisms, present throughout our evolutionary history, have helped to develop immunoregulatory mechanisms that prevent inappropriate immune responses by the host. Using a mouse model of allergic pulmonary inflammation, we report that treatment with an ubiquitous saprophytic mycobacterium, Mycobacterium vaccae, significantly reduces allergic inflammation by decreasing type 2 responses such as eosinophilia and IL-4 expression. Rather than observing an increase in type-1 cytokine expression, we found elevated production of IL-10 in the lungs suggesting a role for regulatory T cells. Since induction of these cells may be dependent on APC, we investigated the effects of M. vaccae treatment on pulmonary CD11c+ cells. Increased levels of IL-10, TGF-beta and IFN-alpha mRNA were detected in CD11c+ cells from M. vaccae-treated allergic mice. We propose that M. vaccae-induced CD11c+ cells have a potential regulatory role at the site of inflammation through their secretion of immunomodulatory cytokines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigen-Presenting Cells / chemistry
  • Antigen-Presenting Cells / immunology*
  • Bronchoalveolar Lavage Fluid / immunology
  • CD11c Antigen / analysis*
  • Cytokines / biosynthesis
  • Female
  • Inflammation / immunology
  • Inflammation / therapy
  • Interleukin-2 / biosynthesis
  • Lung / cytology
  • Lung / immunology*
  • Mice
  • Mice, Inbred BALB C
  • Mycobacterium*
  • Respiratory Hypersensitivity / immunology*
  • Respiratory Hypersensitivity / therapy
  • Th2 Cells / immunology


  • CD11c Antigen
  • Cytokines
  • Interleukin-2