Effects of inflammatory and/or immune stimuli on T-cell activation and their modulation by HDACi. (Left panel) How multiple mechanisms promote Teff cell resistance to Treg suppression, impair Treg function, and inhibit the development of iTregs. Intervention points for HDACi, as identified from the current literature, are indicated in red balls (inhibition) and green balls (stimulation). (Right panel) Mechanisms by which HDACi can promote resolution of inflammation, including through modulation of T-cell activation and enhancement of Treg suppressive functions.