Human activated T lymphocytes modulate IDO expression in tumors through Th1/Th2 balance

Jessica Godin-Ethier, Sandy Pelletier, Laïla Aïcha Hanafi, Philippe O. Gannon, Marie Andrée Forget, Jean Pierre Routy, Mohamed Rachid Boulassel, Urszula Krzemien, Simon Tanguay, Jean Baptiste Lattouf, Nathalie Arbour, Réjean Lapointe*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

44 Citations (Scopus)


Previous cancer vaccination approaches have shown some efficiency in generating measurable immune responses, but they have rarely led to tumor regression. It is therefore possible that tumors emerge with the capacity to down-regulate immune counterparts, through the local production of immunosuppressive molecules, such as IDO. Although it is known that IDO exerts suppressive effects on T cell functions, the mechanisms of IDO regulation in tumor cells remain to be characterized. Here, we demonstrate that activated T cells can induce functional IDO expression in breast and kidney tumor cell lines, and that this is partly attributable to IFN-γ. Moreover, we found that IL-13, a Th2 cytokine, has a negative modulatory effect on IDO expression. Furthermore, we report IDO expression in the majority of breast and kidney carcinoma samples, with infiltration of activated Th1-polarized T cells in human tumors. These findings demonstrate complex control of immune activity within tumors. Future immune therapeutic interventions should thus include strategies to counteract these negative mechanisms.

Original languageEnglish
Pages (from-to)7752-7760
Number of pages9
JournalJournal of Immunology
Issue number12
Publication statusPublished - Dec 15 2009
Externally publishedYes

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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