Detection of Indoleamine 2,3‑dioxygenase/IDO in Human MDSCs by Flow Cytometry. Human myeloid-derived suppressor cells (MDSCs) treated with 10 ng/mL Recombinant Human IL‑6 (Catalog # 206-IL) and 10 ng/mL Recombinant Human GM‑CSF (Catalog # 215-GM) for 7 days were stained with Mouse Anti-Human Siglec‑3/CD33 APC‑conjugated Monoclonal Antibody (Catalog # FAB1137A) and either (A) Mouse Anti-Human Indoleamine 2,3‑dioxygenase/IDO Alexa Fluor® 488‑conjugated Monoclonal Antibody (Catalog # IC6030G) or (B) Mouse IgG1 Alexa Fluor 488 Isotype Control (Catalog # IC002G). To facilitate intracellular staining, cells were fixed with Flow Cytometry Fixation Buffer (Catalog # FC004) and permeabilized with Flow Cytometry Permeabilization/Wash Buffer I (Catalog # FC005). View our protocol for Staining Intracellular Molecules.
Preparation and Storage
The product is shipped with polar packs. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage
Protect from light. Do not freeze.
12 months from date of receipt, 2 to 8 °C as supplied.
Background: Indoleamine 2,3-dioxygenase/IDO
Indoleamine 2,3-dioxygenase (also known as IDO) is a heme-containing intracellular dioxygenase catalyzing the degradation of the essential amino acid L-tryptophan to N-formyl-kynurenine (1). This degradation is the first and rate-limiting step of the L-kynurenine pathway (2). IDO is widely expressed in dendritic cells, macrophages, microglia, eosinophils, fibroblasts, endothelial cells, and most tumor cells. In immune cells, its expression is mainly induced by cytokines such as IFN‑ gamma, IFN-alpha, IFN-beta, and IL‑10. IDO has an antimicrobial function due to its decreasing the availability of the essential amino acid tryptophan in inflammatory environments (3). Recent studies have demonstrated that IDO induces immunosuppression during infection, pregnancy, transplantation, autoimmunity, and neoplasia (3-5).
Lewis-Ballester, A. et al. (2009) Proc. Natl. Acad. Sci. USA. 106:17371.
Costantino, G. (2009) Expert Opin. Ther. Targets 13:247.
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