Modulation of indoleamine 2,3-dioxygenase by interferon-γ in human placental chorionic villi

Abstract

The effect of interferon-γ on indoleamine 2,3-dioxygenase, a tryptophan catabolizing enzyme, was studied in cultured human placental chorionic villi. The activity of indoleamine 2,3-dioxygenase was markedly stimulated by interferon-γ in a time- and concentration-dependent manner. Interferon-α and interferon-β also showed a slight stimulatory effect on indoleamine 2,3- dioxygenase activity. The level of indoleamine 2,3-dioxygenase mRNA expression (determined by reverse transcription - polymerase chain reaction) was also enhanced by interferon-γ. Interleukin-4 showed a dose-dependent inhibitory effect on interferon-γ-induced stimulation of indoleamine 2,3- dioxygenase activity and mRNA expression.