Interleukin-2 (IL-2) is one of the most important cytokines of adaptive immunity. It was first identified as a principal autocrine mitogenic factor for T cells, as well as being the first product of recombinand DNA technology to be used as immuno-boosting treatment for human experimentation in pathologies in which immune modulation was a promising therapeutic strategy (e.g. cancer or AIDS). However, its role in adaptive immune response, as it was later discovered, goes well beyond that of a “mere” aspecific growth factor for T cells. Quite soon, in fact, researcers had to deal with the baffling evidence that patients with autoimmune disease displayed low production of IL-2, while mouse models with compromised IL-2 signal axis developed autoimmune conditions, a puzzle that was clarified only when Tregs were discovered.
In this review, Abul K. Abbas (a name which needs absolutely no introductions) and collegues revised the history, biology, genetics and the therapeutic approaches based on IL-2 known so far.