Fig. 3.

Effect of interferon (IFN)-γ and 1-methyl-tryptophan on tryptophan catabolism by indoleamine 2,3-dioxygenase in placental explants [25]. Villous explants were cultured with or without 1,000 unit mL-1 IFN-γ and/or 2 mM 1-methyl-tryptophan (1-Met-Trp) or vehicle (Nil) for 36 hours. Concentrations of tryptophan (A) and kynurenine (B) in the conditioned medium were analysed by high-performance liquid chromatography. Values are mean±standard deviation of five separate experiments with triplicate assay from five different samples. Control, values without culture; ND, not detectable. ^a)Significantly different from Nil; ^b)Significantly different from IFN-γ.