Editors' ChoiceImmunology

DCs Show Self-Control

Science's STKE  17 Sep 2002:
Vol. 2002, Issue 150, pp. tw341
DOI: 10.1126/stke.2002.150.tw341

Dendritic cells (DCs) are increasingly being recognized for their ability to shut down some types of immune response and for contributing to the state of immune tolerance. Elucidation of putative tolerogenic DC subsets is underway, although the mechanisms by which these cells might modulate immunity have yet to be established. Munn et al. now describe a subset of human DCs that can inhibit T cell responses, at least in vitro, to alloantigens through the catabolism of tryptophan by the enzyme indoleamine 2,3-dioxygenase (IDO). It is known that IDO can prevent antigen-specific responses of T cells in vivo as well as in vitro. The present demonstration that a subset of human DCs can inhibit T cell responses via IDO in vitro makes it plausible that these cells might use the same mechanism in vivo. Whether DCs actually regulate immune responses to self-antigens, transplants, and tumors by this mechanism remains to be established.

D. H. Munn, M. D. Sharma, J. R. Lee, K. G. Jhaver, T. S. Johnson, D. B. Keskin, B. Marshall, P. Chandler, S. J. Antonia, R. Burgess, C. L. Slingluff Jr., A. L. Mellor, Potential regulatory function of human dendritic cells expressing indoleamine 2,3-dioxygenase. Science 297, 1867-1870 (2002). [Abstract] [Full Text]