Distinct regulatory CD4+T cell subsets; differences between naïve and antigen specific T regulatory cells.

Effector T cells have functional subpopulations with distinct cytokine, cytokine receptor, chemokine receptor and transcription factors. We review how activation of antigen specific Treg induces expression of cytokines, cytokine receptors and chemokine receptors depending upon the effector lineage they are activated by. Activated Treg express receptors that are directly related to the effector T cell lineage. Other classes of Treg are induced in the periphery from effector lineage CD4(+)CD25(-)FOXP3(-)CD127(high)T cells, either by IL-10 or TGF-β or by association with activated CD4(+)CD25(+)FOXP3(+)Treg. Thus Treg are produced and adapt to the specific immune inflammatory environment they are activated within. Activated Treg produce different molecules to mediate suppression, which are tailored to the immune response they are activated by and control.