Nori Monkey IDO-1 ELISA Kit Summary

Alternative names for IDO-1: Indoleamine-pyrrole 2,3-dioxygenase, IDO1, Indoleamine 2,3-dioxygenase 1, IDO, INDO

Alternative names for monkey: Non-human primate, Rhesus macaque, Cynomolgus macaque, Baboons, squirrel monkey, common marmoset, chimpanzee, capuchin monkey, spider monkey, howler monkey,

Standard Curve

Kit Components
1. Pre-coated 96-well Microplate
2. Biotinylated Detection Antibody
3. Streptavidin-HRP Conjugate
4. Lyophilized Standards
5. TMB One-Step Substrate
6. Stop Solution
7. 20 x PBS
8. Assay Buffer

Other Materials Required but not Provided:
1. Microplate Reader capable of measuring absorption at 450 nm
2. Log-log graph paper or computer and software for ELISA data analysis
3. Precision pipettes (1-1000 µl)
4. Multi-channel pipettes (300 µl)
5. Distilled or deionized water

Protocol Outline
1. Prepare all reagents, samples and standards as instructed in the datasheet.
2. Add 100 µl of Standard or samples to each well and incubate 1 h at RT.
3. Add 100 µl of Working Detection Antibody to each well and incubate 1 h at RT.
4. Add 100 µl of Working Streptavidin-HRP to each well and incubate 20 min at RT.
5. Add 100 µl of Substrate to each well and incubate 5-30 min at RT.
6. Add 50 µl of Stop Solution to each well and read at 450 nm immediately.

Background:

Indoleamine-pyrrole 2,3-dioxygenase (IDO or INDO EC 1.13.11.52) is a heme-containing enzyme that is encoded by the IDO1 gene.^[1] It is one of three enzymes that catalyze the first and rate-limiting step in the kynurenine pathway, the O₂-dependent oxidation of L-tryptophan to N-formylkynurenine, the others being IDO2 and tryptophan 2,3-dioxygenase (TDO). IDO has been implicated in immune modulation through its ability to limit T-cell function and engage mechanisms of immune tolerance.^[2] PGE2 can elevate the expression of IDO in CD11C⁺ dendritic cells and promotes the development of functional T-regulatory cells (Treg cells), which inhibit T-cell activity. IDO is an immune checkpoint molecule that it is an immunomodulatory enzyme produced by some alternatively activated macrophages and other immunoregulatory cells.^[3] IDO is known to suppress T and NK cells, generate and activate Tregs and myeloid-derived suppressor cells, and promote the growth of new blood cells to feed the tumor.^[4] IDO permits tumor cells to escape the immune system by depletion of L-tryptophan in the tumor microenvironment and by production of the catabolic product kynurenine, which selectively impairs the growth and survival of T-cells. A wide range of human cancers overexpress human IDO (hIDO).^[5] Emerging evidence suggests that IDO becomes activated during tumor development, helping malignant cells escape eradication by the immune system.^[2][4] In mice, IDO has a normal immune checkpoint function in immune tolerance in pregnancy, suppressing the mother’s immune system.^[6] By 2018 the function of IDO as a checkpoint used by tumors to escape immune surveillance was a focus of research and drug discovery efforts,^[5] as well as efforts to understand if it could be used as a biomarker for prognosis.^[6] As of 2018, it appeared that overexpression of IDO in some tumors correlated with swifter death, while in kidney and liver cancers it appeared to correlate with better outcomes.^[6]

References

1.      Dai W and Gupta SL. (1990) Biochem. Biophys. Res. Commun. 168 (1), 1-8.

1. Munn DH, Mellor AL (2013). Trends in Immunology. 34 (3): 137–43.
2. Moon YW, Hajjar J, Hwu P, Naing A (2015). J Immunother Cancer. 3: 51.
3. Prendergast GC, et al. (2014). Cancer Immunol Immunother. 63 (7): 721–35.
4. Jiang T, et al. (2015). Future Medicinal Chemistry. 7 (2): 185–201.
5. Yu CP, et al. (2018). Cellular Physiology and Biochemistry. 49 (1): 134–143.