Effects of B7H1-blocking and OX40-agonist mAbs on CD4+ IL-10–expressing and Foxp3+ Treg in vaccinated mice. Mice (5 per group) were inoculated with MOPC-21 tumor cells, and when subcutaneous tumors reached 25 mm2, received 3 injections (every 3 days) of PBS, DKK1 DNA (DKK1), DKK1 DNA plus CpG (DKK1-CpG), DKK1 DNA plus CpG in combination with anti-B7H1 mAbs (DKK1-CpG+ B7H1) or DKK1 DNA plus CpG in combination with anti-OX40 mAbs (DKK1-CpG+ OX40). Seven days after the third treatment, T cells were isolated from spleens and tumors, restimulated by irradiated tumor cells for 5 days, and analyzed with flow cytometry. Shown are percentages of CD4+ T cells expressing IL-10 or FoxP3 (Tregs) in the spleens and tumors of mice receiving different treatments as indicated. Representative results of 1 of 2 independent experiments are shown. *P < .05; **P < .01, compared with DKK1 vaccine only.
