Foxp3+ CD4+ CD25+ regulatory cell (Treg) subsets that maintain immunologic homeostasis have been considered to be a homogeneous population of naturally occurring, thymus-derived CD4+CD25+ cells (nTregs). However, similar Foxp3+ Tregs can be induced from CD25- precursors in vivo, and ex vivo with interleukin 2 (IL-2) and transforming growth factor β (TGF-β) (iTregs). These two subsets differ in their principal antigen specificities and in the T-cell receptor signal strength and co-stimulatory requirements needed for their generation. However, whether iTregs have any unique functions in vivo has been unclear. Although IL-6 can convert nTregs to Th17 cells, iTregs induced by IL-2 and TGF-β are resistant to this cytokine and thereby might retain suppressive function at inflammatory sites. Thus, nTregs and iTregs may have different roles in the adaptive immune response.
All Science Journal Classification (ASJC) codes
- Immunology and Allergy