Cerebral cortex and lung indoleamine-2,3-dioxygenase activity is increased in type-D retrovirus infected macaques.

Increased concentrations of the neuroactive kynurenine pathway metabolites, quinolinic acid (QUIN) and kynurenic acid (KYNA), occur in the CSF of humans infected with the human immunodeficiency virus and macaques infected with retroviruses, including the D/1/California serotype. In the present study, increased activity of indoleamine-2,3-dioxygenase (IDO), the first enzyme of the kynurenine pathway, occurred in cerebral cortex and lung of macaques with clinical SAIDS. Such increases provide a mechanism to accelerate the formation of kynurenine pathway metabolites in both systemic tissues and the central nervous system.