Functional expression of indoleamine 2,3-dioxygenase by murine CD8α+ dendritic cells

Francesca Fallarino, Carmine Vacca, Ciriana Orabona, Maria L. Belladonna, Roberta Bianchi, Brendan Marshall, Derin B. Keskin, Andrew L. Mellor, Maria C. Fioretti, Ursula Grohmann, Paolo Puccetti

Research output: Contribution to journalArticlepeer-review

219 Scopus citations


Immunoregulatory antigen-presenting cells (APC) play an important role in maintaining T cell homeostasis and self-tolerance. In particular, recent evidence demonstrates a role for inhibition of T cell proliferation by macrophage tryptophan catabolism involving the activity of the enzyme indoleamine 2,3-dioxygenase (IDO). Dendritic cells (DC) have also been shown to exert immunoregulatory effects mediated by tryptophan catabolism and to cause T cell apoptosis. In the present study, we have comparatively analyzed the expression of IDO activity by murine macrophages and splenic DC. By means of PCR, Western blotting and measurements of enzyme functional activity, we obtained evidence that, different from macrophages, DC constitutively express IDO. Following activation by IFN-γ, the latter cells, in particular the CD8α+ subset, exhibit high functional activity and, unlike macrophages, mediate apoptosis of Th cells in vitro. Therefore, in the mouse, CD8α+ DC may be unique APC capable of fully expressing the IDO mechanism functionally.

Original languageEnglish (US)
Pages (from-to)65-68
Number of pages4
JournalInternational Immunology
Issue number1
StatePublished - 2002


  • Antigen-presenting cells
  • Indoleamie 2,3-dioxygenase
  • T cell apoptosis
  • Tryptophan metabolism

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


Dive into the research topics of 'Functional expression of indoleamine 2,3-dioxygenase by murine CD8α+ dendritic cells'. Together they form a unique fingerprint.

Cite this