Skin-homing CLA+ T cells and regulatory CD25+ T cells represent major subsets of human peripheral blood memory T cells migrating in response to CCL1/I-309
Colantonio, L.; Iellem, A.; Sinigaglia, F.; D'Ambrosio, D.
European Journal of Immunology 32(12): 3506-3514
ISSN/ISBN: 0014-2980 PMID: 12442333 DOI: 10.1002/1521-4141(200212)32:12<3506::aid-immu3506>3.0.co;2-#
Functionally distinct T cell subsets exhibit specific chemokine receptor profiles that regulate their tissue localization. Here, we show that human peripheral blood CD4(+) and CD8(+) cutaneous (CLA(+)), but not intestinal memory (integrin beta(7) (+)) nor IL-4-producing T cells, represent major subpopulations of circulating T cells that specifically migrate in response to the chemokine I-309/CCL1 by virtue of CCR8 expression. Expression of CCR8 is markedly up-regulated upon activation and in vitro culture of human CLA(+) T cells, suggesting the involvement of CCR8 in localization of cutaneous memory T cells to the skin. Interestingly, amongst circulating memory CD4(+)CD45RO(+) T cells, chemotactic responsiveness to CCL1 is restricted to cells expressing CD25 and/or CLA surface markers for regulatory T cells (Treg) and skin-homing T cells and maximal responsiveness is observed on CLA(+)CD25(+)T cells. Such pattern of CCL1 responsiveness suggests that the CCR8/CCL1 axis may regulate trafficking of cutaneous Treg and memory T cells into the skin.