**Abstract**

The aim of this study is to show the effects of activating aryl hydrocarbon receptor (AhR) by specific ligands, on the expression of responsive genes. Specific AhR-ligands were reported to play an important role in immune regulation. This chapter will focus mostly on the effects of activating AhR with different ligands on autoimmunity. Findings showed the possibility of using the AhR to treat inflammatory and autoimmune diseases in mice. AhR ligation with specific ligands can affect T cell differentiation, through activation of CD4+ Foxp3+ regulatory T cells and downregulation of the pro-inflammatory T helper 17 cells. The results showed the effects of specific AhR-ligands on the production of pro-inflammatory and/ or anti-inflammatory T cell subsets, the potential to use AhR-ligands in regulating the inflammation of organ/tissues in various diseases, suggesting that specific AhR-ligands could be used for immune regulation in pathogenesis of autoimmune diseases of human and mice.

**Keywords:** aryl hydrocarbon receptor, T helper 17, T regulatory cells, autoimmune disease, immune regulation
