Regulatory T cells (Tregs) play an indispensable role in maintaining immunological
unresponsiveness to self-antigens and in suppressing excessive immune responses
deleterious to the host. Tregs are produced in the thymus as a functionally mature
subpopulation of T cells and can also be induced from naive T cells in the periphery. Recent
research reveals the cellular and molecular basis of Treg development and function and
implicates dysregulation of Tregs in immunological disease.