Immunotherapy and immunoescape in colorectal cancer

Figure 1 IFN-γ induces IDO mRNA and enzymatic activity in colon cancer cells. A: IDO mRNA was induced after 48 h stimulation with 1000 IU/mL of IFN-γ, as assessed by real time-PCR; B: In the same culture conditions, IDO activity was measured in CT26 cellular extracts as previously described by Takikawa et al[83].

Figure 2 Systemic treatment with agonist anti-CD137 monoclonal antibodies eradicates transplanted murine colon cancers. Mice subcu-taneously grafted with 5 x 10⁵ CT26 or MC38 cells were treated with anti-CD137 (2A) mAb or polyclonal rat IgG as a control. Sequential follow up of tumor size (mean diameter) is depicted for individual mice.