Competition for IL-2 between regulatory and effector T cells to chisel immune responses

In this review we discuss how the competition for cytokines between different cells of the immune system can shape the system wide immune response. We focus on interleukin-2 (1152) secretion by activated effector T cells (T-eff) and on the competition for 11,2 consumption between T-eff and regulatory T cells (T-reg). We discuss the evidence for the mechanism in which the depletion of 1152 by Treg cells would be sufficient to suppress an autoimmune response, yet not strong enough to prevent an immune response. We present quantitative estimations and summarize our modeling effort to show that the tug-of-war between Treg and T-eff cells for 1152 molecules can be won by Treg cells in the case of weak activation of T-eff leading to the suppression of the immune response. Or, for strongly activated T-eff cells, it can be won by T-eff cells bringing about the activation of the whole adaptive immune system. Finally, we discuss some recent applications attempting to achieve clinical effects through the modulation of 1152 consumption by Treg compartment.