Activated CD1d-restricted natural killer T cells secrete IL-2: innate help for CD4+CD25+ regulatory T cells?
Article first published online: 15 MAR 2005
Copyright © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
European Journal of Immunology
Volume 35, Issue 4, pages 1193–1200, April 2005
How to Cite
Jiang, S., Game, David S., Davies, D., Lombardi, G. and Lechler, Robert I. (2005), Activated CD1d-restricted natural killer T cells secrete IL-2: innate help for CD4+CD25+ regulatory T cells?. Eur. J. Immunol., 35: 1193–1200. doi: 10.1002/eji.200425899
- Issue published online: 22 MAR 2005
- Article first published online: 15 MAR 2005
- Manuscript Accepted: 14 FEB 2005
- Manuscript Revised: 31 JAN 2005
- Manuscript Received: 1 DEC 2004
- CD4+CD25+ regulatory T cells;
- NKT cells
CD4+CD25+ and CD1d-restricted natural killer T (NKT) cells are thymus-derived self-reactive regulatory T cells that play a key role in the control of pathological immune responses. Little is known about functional cooperation between innate regulatory NKT cells and adaptive CD4+CD25+ regulatory cells. Here we show that human CD4+Vα24+Vβ11+ (CD4+ NKT) cells isolated from peripheral blood by flow cytometric cell sorting secrete substantial amounts of IL-2 after stimulation with dendritic cells (DC) and α-Galactosylceramide. When cocultured with CD4+CD25+ cells, CD4+ NKT cells promoted moderate proliferation of CD4+CD25+ cells. The proliferation of CD4+CD25+ T cells was due to soluble IL-2 produced by activated CD4+ NKT cells. The expanded CD4+CD25+ cells remained anergic and retained their potent suppressive properties. These findings indicate that unlike conventional CD4+ and CD8+ T cells, which are susceptible to CD4+CD25+ regulatory cell suppression, NKT cells promote CD4+CD25+ regulatory cell proliferation. These data raise the possibility that NKT cells can function as helper cells to CD4+CD25+ regulatory T cells, thereby providing a link between the two naturally occurring populations of regulatory T cells.