The aryl hydrocarbon receptor in immunity

Trends Immunol. 2009 Sep;30(9):447-54. doi: 10.1016/ Epub 2009 Aug 21.


Low-molecular-weight chemicals or xenobiotics might contribute to the increasing prevalence of allergies and autoimmunity. Certain chemicals can alter immune responses via their action on the cytosolic transcription factor aryl hydrocarbon receptor (AhR). AhR recognizes numerous small xenobiotic and natural molecules, such as dioxin and the tryptophan photoproduct 6-formylindolo[3,2-b]carbazole. Although AhR is best known for mediating dioxin toxicity, knockout studies have indicated that AhR also plays a role in normal physiology, including certain immune responses. In particular, Th17 cells and dendritic cells express high levels of AhR. We review here current evidence for the physiological role of AhR in the immune system, focussing in particular on T-cell biology.

Publication types

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

MeSH terms

  • Animals
  • Autoimmunity
  • Carbazoles / metabolism
  • Cell Differentiation
  • Dendritic Cells / immunology
  • Dendritic Cells / metabolism
  • Humans
  • Interleukin-17 / immunology
  • Interleukin-17 / metabolism*
  • Mice
  • Mice, Knockout
  • Receptors, Aryl Hydrocarbon / genetics
  • Receptors, Aryl Hydrocarbon / immunology
  • Receptors, Aryl Hydrocarbon / metabolism*
  • Signal Transduction / immunology
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism*
  • T-Lymphocytes / pathology


  • 6-formylindolo(3,2-b)carbazole
  • Carbazoles
  • Interleukin-17
  • Receptors, Aryl Hydrocarbon