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ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH301:11

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Molecules in focus: indoleamine 2,3-dioxygenase.

Nicholas J C King1, Shane R Thomas

  • 1Department of Pathology, Bosch Institute, School of Medical Sciences, University of Sydney, Sydney, Australia. nickk@pathology.usyd.edu.au

The International Journal of Biochemistry & Cell Biology
|February 27, 2007
PubMed
Summary

Indoleamine 2,3-dioxygenase (IDO) degrades l-tryptophan, potentially inhibiting pathogens. Paradoxically, IDO also suppresses T cell responses, promoting immune tolerance in various diseases.

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Area of Science:

  • Biochemistry
  • Immunology

Background:

  • Indoleamine 2,3-dioxygenase (IDO) is a heme enzyme initiating l-tryptophan degradation via the kynurenine pathway.
  • IDO-mediated tryptophan depletion can inhibit pathogen growth.
  • IDO is increasingly recognized as a key immune control enzyme.

Purpose of the Study:

  • To review the biochemical properties of IDO.
  • To outline known and hypothetical functions of IDO.
  • To discuss medical implications of modulating IDO activity in health and disease.

Main Methods:

  • Literature review of IDO's biochemical properties.
  • Analysis of IDO's role in immune tolerance.
  • Examination of IDO's involvement in various medical conditions.

Main Results:

  • IDO initiates l-tryptophan catabolism, impacting pathogen defense.
  • IDO expression suppresses local T cell responses, promoting immune tolerance.
  • IDO plays a role in infectious diseases, cancer, transplantation, and autoimmune disorders.

Conclusions:

  • IDO's dual role in pathogen inhibition and immune tolerance is significant.
  • Modulating IDO activity offers potential therapeutic strategies for various diseases.
  • Further research into IDO's functions and therapeutic implications is warranted.