Figure 3. Quantitative determination of IDO protein in HCECs. The top panel shows the quantification of A. HCECs were unstimulated (A: lane 1) and stimulated with 500 ng/ml IFN-γ (A: lane 2), 100 U/ml TNF-α (A: lane 3), or IFN-γ+100 U/ml TNF-α (A: lane 4) for 72 h. An undetectable protein band was found in unstimulated HCECs (A: lane 1) and stimulated HCECs with 100 U/ml TNF-α (A: lane 3). Obvious upregulation of protein expression is seen in cytokine stimulation with 500 ng/ml IFN-γ for 72 h (A: lane 2) and 500 ng/ml IFN-γ+100 U/ml TNF-α for 72 h (A: lane 4). The bottom panel shows the IDO control protein at 0.3 µg (B: lane 5), 1.25 µg (B: lane 6), and 2.5 µg (B: lane 7). For the detection of the bands, protein of three independent experiments has been pooled. Thus, no error bars will be shown.