"Catabolism of amino acids is an ancient survival strategy that also controls immune responses in mammals. Indoleamine 2,3-dioxygenase (IDO), a tryptophan catabolizing enzyme, is recognized as an authentic regulator of immunity in several physiopathologic conditions, including autoimmune diseases, in which it is often defective, and neoplasia, in which it promotes immune unresponsiveness. The PI’s ...