Manipulation of indoleamine 2,3-dioxygenase (IDO) for clinical transplantation: promises and challenges.
BACKGROUND
Since the discovery that indoleamine 2,3-dioxygenase (IDO) is a modulator for maintenance of fetomaternal immuno-privilege state, it has been implicated in tumour tolerance, autoimmune diseases and asthma. IDO is an IFN-gamma-inducible, intracellular enzyme that catalyzes the initial and rate-limiting step in the degradation of tryptophan. It has been suggested that IDO can regulate the immune system either through deprivation of tryptophan that is essential for T cell proliferation or via cytotoxic effects of kynurenine pathway metabolites on T cell survival.


METHODS
The sources of information used were obtained through Pubmed/Medline.


CONCLUSIONS
While IDO emerges as a regulator of immunity, its role in controlling allo-response is unfolding. IDO can control T cell responses to allo-antigens and induce generation of allo-specific regulatory T cells. Exploiting IDO as a modulator of transplant rejection, many groups have manipulated its activity to prolong allograft survival in transplantation models. Despite the initial promise, its application to clinical transplantation may be limited. We therefore examine the potentials and limitations associated with clinical translation of IDO into a therapeutic.
Quan
Jianchao
J
Oxford University, John Radcliffe Hospital, Nuffield Department of Surgery, Headley Way, Oxford, OX3 9DU, UK.
Tan
Peng H
PH
MacDonald
Andrew
A
Friend
Peter J
PJ
D000818:Animals; D002384:Catalysis; D002470:Cell Survival; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D007107:Immune System; D007166:Immunosuppressive Agents / Q000494:pharmacology; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase / Q000737:chemistry*; D007371:Interferon-gamma / Q000378:metabolism; D016377:Organ Transplantation / Q000379:methods*; D011489:Protein Denaturation; D013601:T-Lymphocytes / Q000276:immunology; D018418:Th2 Cells / Q000378:metabolism; D014364:Tryptophan / Q000737:chemistry
D007166:Immunosuppressive Agents; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D007371:Interferon-gamma; D014364:Tryptophan