J Exp Med. 2006 Jul 10;203(7):1693-700. Epub 2006 Jul 3.

Expression of interleukin (IL)-2 and IL-7 receptors discriminates between human regulatory and activated T cells.

Seddiki N, Santner-Nanan B, Martinson J, Zaunders J, Sasson S, Landay A, Solomon M, Selby W, Alexander SI, Nanan R, Kelleher A, Fazekas de St Groth B.

Source

Centenary Institute of Cancer Medicine and Cell Biology, Faculty of Medicine, University of Sydney, Newtown, NSW 2042, Australia.

Abstract

Abnormalities in CD4(+)CD25(+)Foxp3(+) regulatory T (T reg) cells have been implicated in susceptibility to allergic, autoimmune, and immunoinflammatory conditions. However, phenotypic and functional assessment of human T reg cells has been hampered by difficulty in distinguishing between CD25-expressing activated and regulatory T cells. Here, we show that expression of CD127, the alpha chain of the interleukin-7 receptor, allows an unambiguous flow cytometry-based distinction to be made between CD127(lo) T reg cells and CD127(hi) conventional T cells within the CD25(+)CD45RO(+)RA(-) effector/memory and CD45RA(+)RO(-) naive compartments in peripheral blood and lymph node. In healthy volunteers, peripheral blood CD25(+)CD127(lo) cells comprised 6.35 +/- 0.26% of CD4(+) T cells, of which 2.05 +/- 0.14% expressed the naive subset marker CD45RA. Expression of FoxP3 protein and the CD127(lo) phenotype were highly correlated within the CD4(+)CD25(+) population. Moreover, both effector/memory and naive CD25(+)CD127(lo) cells manifested suppressive activity in vitro, whereas CD25(+)CD127(hi) cells did not. Cell surface expression of CD127 therefore allows accurate estimation of T reg cell numbers and isolation of pure populations for in vitro studies and should contribute to our understanding of regulatory abnormalities in immunopathic diseases.