IDO

IDO

Indoleamine 2,3-dioxygenase (IDO) is an enzyme that is upregulated upon T cell activation or inflammation and leads to the suppression of the immune response and activation of regulatory T cells (Tregs).1

Tumor cells hijack this immunosuppressive process by upregulating IDO activity and depleting tryptophan in the tumor microenvironment. Without tryptophan to fuel the immune cells, cytotoxic T cells starve and immunosuppressive Tregs are upregulated leading to a failure of the immune system to respond appropriately to the cancer.2-5

IDO expression is upregulated in several types of cancer.6

References
1. Moon YW et al. J Immunother Cancer. 2015; 3:51.
2. Löb S et al. Cancer Immunol Immunother. 2009;58(1):153-157.
3. Liu P  et al. BMC Cancer. 2009;9:416. doi: 10.1186/1471-2407-9-416.
4. Wainwright DA et al. Clin Cancer Res. 2012;18(22):6110-6121.
5. Fallarino F et al. J Immunol. 2006;176(11):6752-6761.
6. Uyttenhove C et al. Nat Med. 2003 Oct; 9(10):1269-74.