AUTHOR=Klein Matthias , Bopp Tobias TITLE=Cyclic AMP Represents a Crucial Component of Treg Cell-Mediated Immune Regulation JOURNAL=Frontiers in Immunology VOLUME=7 YEAR=2016 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2016.00315 DOI=10.3389/fimmu.2016.00315 ISSN=1664-3224 ABSTRACT=
T regulatory (Treg) cells are one of the key players in the immune tolerance network, and a plethora of manuscripts have described their development and function in the course of the last two decades. Nevertheless, it is still a matter of debate as to which mechanisms and agents are employed by Treg cells, providing the basis of their suppressive potency. One of the important candidates is cyclic AMP (cAMP), which is long known as a potent suppressor at least of T cell activation and function. While this suppressive function by itself is widely accepted, the source and the mechanism of action of cAMP are less clear, and a multitude of seemingly contradictory data allow for, in principle, two different scenarios of cAMP-mediated suppression. In one scenario, Treg cells contain high amounts of cAMP and convey this small molecule