CD39 and CD73 in immunity and inflammation

Highlights • CD39 and CD73 are important for calibrating the duration, magnitude, and composition of the ‘purinergic halo’ surrounding immune cells. • CD39 and CD73 degrade ATP, ADP, and AMP to adenosine; they can be viewed as ‘immunological switches’ that shift ATP-driven proinflammatory immune cell activity toward an anti-inflammatory state mediated by adenosine. • CD39 and CD73 are highly expressed on the surface of Foxp3+ Tregs and have been increasingly used as markers of Tregs. • CD39 and CD73 are important for the immunosuppressive activity of Tregs. • CD39 and CD73 generate an immunosuppressed environment, characterized by increased adenosine levels, which promotes the development and progression of cancer.