A2ar

A2AR is the acronym for "Adenosine A2A Receptor" an adenosine receptor activated by the purine nucleoside adenosine. A2AR belongs to the anti-inflammatory immune checkpoints (ICs).

Anti-inflammatory immune checkpoints inhibit the immunoreactivity of T lymphocytes, in contrast to pro-inflammatory ICs, which increase the immunoreactivity of T lymphocytes. The immune checkpoints are activated by precisely fitting cytokines (ligands) that are presented and released by other cells, e.g. tumor cells. This immunological mechanism plays an important role in "tumor evasion".

Currently, 4 adenosine receptors (purinoceptors) are known, which are designated as A1, A2A, A2B and A3. They play a role in the central nervous system and in the regulation of cardiovascular functions and immune reactions. The effects of the xanthines: caffeine, theophylline and theobromine are partly due to an interaction with adenosine receptors. The A2A receptor antagonist, istradefylline (an analogue of caffeine), is used in the treatment of Parkinson's disease.

1. Leone RD et al (2015) A2aR antagonists: Next generation checkpoint blockade for cancer immunotherapy. Comput Struct Biotechnol J 13:265-272.