Fig. 1.

IDO is not anti-inflammatory. a Skin histology after TPA treatment alone. Similar epidermal thickening is observed in wild-type and Ido1 ^−/− animals at 24 and 48 h after a single application of TPA and remains evident through 5 weeks of repeated treatment. For comparison, the last panels illustrate histology of DMBA + TPA-treated skin at 22 weeks including papilloma formation in the wild-type animal. b Skin histology after abrasion wounding. Brackets indicate the nonabraded region 3 days after wounding with the abraded region noted beyond the asterisk. KO, Ido1 ^−/− mice. c Spleen weight after TPA treatment alone. Mice were exposed to TPA alone as noted in (b), killed on day 9, and wet weight of spleens dissected at necropsy determined. Standard error in the data presented is shown