The plasma kynurenine to tryptophan ([Kyn]/[Trp]) ratio is frequently used to express or
reflect the activity of the extrahepatic Trp-degrading enzyme indoleamine 2, 3-dioxygenase …

This paper reviews the body of evidence that not only tryptophan and consequent 5-HT
depletion, but also induction of indoleamine 2, 3-dioxygenase (IDO) and the detrimental …

Progressive HIV infection is characterized by dysregulation of the intestinal immune barrier,
translocation of immunostimulatory microbial products, and chronic systemic inflammation …

Abstract Indoleamine 2, 3-dioxygenase (IDO), an enzyme involved in the catabolism of
tryptophan, is expressed in certain cells and tissues, particularly in antigen-presenting cells …

Tryptophan is an essential amino acid that can be metabolised through different pathways, a
major route being the kynurenine pathway. The first enzyme of the pathway, indoleamine-2 …

The pathogenesis of human and simian immunodeficiency viruses is characterized by CD4+
T cell depletion and chronic T cell activation, leading ultimately to AIDS. CD4+ T helper (TH) …

Endogenous tryptophan metabolism pathways lead to the production of serotonin (5‐
hydroxytryptamine; 5‐HT), kynurenine, and several downstream metabolites which are …

The mammalian intestine harbors one of the largest microbial densities on Earth,
necessitating the implementation of control mechanisms by which the host evaluates the …

The essential amino acid tryptophan is a constituent of proteins and is also a substrate for
two important biosynthetic pathways: the generation of neurotransmitter 5-hydroxytryptamine …

Some macrophages inhibit microbial infections by producing indoleamine 2, 3 dioxygenase
(IDO), which catabolizes tryptophan. Here, Andrew Mellor and David Munn discuss …