Adenosine receptor activation in the Th17 autoimmune responses of experimental autoimmune uveitis

Th17-type autoreactive T cells contribute to pathogenicity in autoimmune diseases, including autoimmune uveitis. However, the mechanisms of regulation of Th17 cell activities remain unsolved and are likely to be tissue- and disease specific. In this review, we have summarized our studies from the murine model of experimental autoimmune uveitis (EAU). The results demonstrate that gamma delta T cells have a regulatory effect on Th17 response. The regulatory effects of gamma delta T cells depend on their action state. Activated gamma delta T cells express significantly high levels of adenosine receptor A2 (A2AR) but low CD73. Both molecules are crucially involved in adenosine generation, thus modifying T cell responses. While the increased expression of A2AR-allows activated gamma delta T cells to bind adenosine more effectively than other immune cells, the decreased CD73 restricts their ability to convert AMP to adenosine. Adenosine affects Th1 and Th17 autoimmune responses differently. Its activation of gamma delta T cells shifts the Th1/Th17 balance towards the Th17 autoreactivity.