IDO mRNA expression and enzymatic activity. (A) IDO mRNA expression, analyzed by real-time PCR, on total RNA extracted from macaques' lymph nodes before initiation of ART (week 0), and after 6 weeks of treatment (ART) and MDX-010 treatment (ART and anti–CTLA-4) for each group. (B) Plasma kynureninetryptophan ratio measured by high-performance liquid chromatography in each group before initiation of ART (week 0), and after 6 weeks of treatment (ART) and MDX-010 (ART and anti–CTLA-4). Changes in IL-2 mRNA (C) and TGF-β (D) induced by ART and ART and anti–CTLA-4 after 6 weeks of treatment in each group. (E) Ratio between the level of IL-2 and TGF-β mRNA. Pre-ART indicates before initiation of ART. For panels A and E, dots represent individual values for each animal; horizontal bars correspond to the median. For panels B-D, horizontal bars within boxes correspond to the median; box limits correspond to the 25th and 75th percentiles; and vertical lines extend to the 10th and 90th percentiles.