Sun et al. Journal of Experimental & Clinical Cancer Research 2011, 30:82 http://www.jeccr.com/content/30/1/82 Page 6 of 10 Figure 2 Effect of IDO+ CHO cells on CD3+T cell apoptosis. (A) Representative FACS scatter plots of CD3+T cells apoptosis 72 h after culture with 200 U/ml human recombinant IL-2. (B) Representative FACS scatter plots of CD3+T cells apoptosis 72 h after co-culture with CHO/EGFP cells. (C) Representative FACS scatter plots of apoptotic CD3+T cells 72 h after co-culture with CHO cells transfected with IDO. (D) Representative FACS scatter plots of apoptotic CD3+T cells 72 h after co-culture with CHO cells transfected with IDO and inhibitor 1-MT. (Q4 region represents cells in the early process of apoptosis; P5 represents the total population of apoptotic CD3+T cells) (E) Relative percentages of apoptotic cells (Annexin V positive and PI negative cells). The columns showed the average (%) ± SD from 3 independent experiments. The differences were statistically significant (P < 0.05), indicating that CHO cells with IDO transfection can significantly induce apoptosis in T cells.