Figure 2.
Regulatory T-cells: development and subsets. Three major subjects of Tregs have been recognized so far. A) Tregs (innate and adaptative): they express CD25, FoxP3, CTLA-4, αβ-TCR, and secrete the immunosuppressive lymphokines IL-10 and TGF-β. B) Tr1 cells: they do not express FoxP3 nor large amount of CD25, secrete IL-10 and TGF-β. Tr1 cells are abundant in the intestine where they elicit their main function that is making tolerance to the many agents that are part of its diet. C) Th3 cells: they are also prevalent in the intestine and like to Tr1 cells act suppressing immune responses to ingested antigens (oral tolerance) by means of TGF-β secretion.