Table 1.

Features of Treg cells in different compartments of the body.

Site	Special features	Main function for Treg cells
Gut	High number of iTreg cells induced by orally delivered antigens and commensal microbes	Oral tolerance (systemic)
Skin	High number of Treg cells in the steady state. UV-radiation induced Treg cells	Immune homeostasis
Lung	Pathogens affect Treg number and function	Induction of tolerance against nasal antigens
Liver	Antigen presentation in the liver may lead to formation of iTreg cells which confer systemic tolerance	Systemic tolerance
Fat tissue	Limited TCR repertoire	Control of sterile, low-grade inflammation in the adipose tissue