Expression of the integrin αEβ7identifies unique subsets of CD25+as well as CD25regulatory T cells

Abstract
Regulatory CD25+CD4+ T cells are considered as important players in T cell homeostasis and self-tolerance. Here we report that the integrin αEβ7, which recognizes epithelial cadherin, identifies the most potent subpopulation of regulatory CD25+ T cells. Strikingly, CD25-negative αE+CD4+ T cells displayed regulatory activity. Both αE+ subsets, CD25+ and CD25, express CTLA-4, suppress T cell proliferation in vitro, and protect mice from colitis in the severe combined immunodeficient model (SCID) in vivo. Whereas αE+CD25+ T cells produce almost no cytokines, αE+CD25 T cells represent a unique subset in which high IL-2, IFN-γ and T helper 2-cytokine production is linked with suppressive function. Thus, the integrin αEβ7 can be regarded as a novel marker for subsets of highly potent, functionally distinct regulatory T cells specialized for crosstalk with epithelial environments.