Involvement of Indoleamine 2,3-Dioxygenase in Impairing Tumor-Infiltrating CD8+ T-Cell Functions in Esophageal Squamous Cell Carcinoma
Figure 5
Effect of IDO on the proliferation and apoptosis of CD8+ T cells from both PBMCs and TILs. (a) Proliferation of CD8+ T cells from PBMCs or TILs was suppressed by IDO-expressing Eca109 cells. CD8+ T cells were cultured in conditioned media and activated with anti-CD3/CD28 antibodies. Proliferation of CD8+ T cells was assayed by [3H] TdR incorporation. (b) Concentrations of Kyn and Try were measured in the supernatants of Eca109 cells treated with or without IFNγ (50 U/mL) and/or 1MT (100 μM) for 24 hr. Kyn and Try productions were analyzed by HPLC. (c) Effect of IDO on the apoptosis of CD8+ T cells from PBMCs or TILs. CD8+ T cells (1–4) or anti-CD3/CD28-activated CD8+ T cells (5–8) from both PBMCs and TILs were cultured in conditioned media derived from IFNγ-treated (2, 4, 6, 8) or untreated (1, 3, 5, 7) Eca109 cells for 4 d, and the population of apoptotic cells was detected by flow cytometric analysis, using Annexin V and Propidium Iodide as indicators. Columns, mean of three independent experiments. Bars, SD. *P < 0.05 compared with CD8+ T cells cultured in conditioned media derived from non-IFNγ-treated Eca109 cells.
