Figure 6

Fludarabine doweregulated IDO1to enhance the antitumour response induced by MV-Edm and CD8⁺NKG2D⁺ cells. (a) LM3 cells were cultured in the presence or absence of 300 nM fludarabine or 100 μM 1-MT for 24 h. Cells were infected with MV-Edm (MOI = 1) for another 24 h or were left uninfected. Cells were washed, harvested and mixed with CD8⁺NKG2D⁺ cells at a ratio of 5:1 (E:T) for 24 h. Cell viability was examined by luminescence spectrometry. Means + SD of triplicates are shown. Similar results were obtained in two independent experiments. (b–e) 4- to 6-week-old male Balb/c nude mice received subcutaneous injections of 1 × 10⁷ LM3 cells in the right flank. When tumours reached an average volume of 40 mm³, mice were randomized to two groups. MV-Edm (5 × 10⁶ PFU each injection) was injected into the tumours on day 0, 1, 7, 14, 21, 28 and 35, followed by intravenous infusion of CD8⁺NKG2D⁺ cells (1 × 10⁷ per mouse), with (filled squares, n = 7) or without (filled circles, n = 7) intraperitoneal injection of fludarabine (0.75 mg per mouse) on day 2, 8, 15, 22, 29 and 36. Mice were sacrificed when tumour volume reached to 2 cm³, or when mice appeared moribund. (b) The scheme depicts the schedules of the in vivo experiment. (c) Tumour growth and (d) the body weight variation were monitored every 3 days. Means + SD are shown. (e) Survival was determined and plotted for Kaplan-Meier survival analysis and analyzed by log-rank test. * P < 0.05, ** P < 0.01.