<p>Mice (3/group) which had been transplanted i.p. with 3 × 10<sup>6</sup> ID8 cells 10 days earlier were injected i.p. twice at 4 days interval with 0.5 mg of control, anti-CD137, anti-PD-1 or anti-PD-1/CD137 mAb. Spleens from treated mice were analyzed for phenotypes and effector functions of CD8<sup>+</sup> T lymphocytes by flow cytometry 7 days after the second mAb injection. The percentages and numbers of CD44<sup>+</sup>CD62L<sup>-</sup> effector/memory and CD44<sup>+</sup>CD62L<sup>+</sup> central memory and IFN-γ- and IL-10-producing cells in the CD8<sup>+</sup> T cell population are shown in (A) and representative dotplots are shown in (B). Data are presented as M±SEM from 3 mice in each group and are representative of 3 independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001, PD-1 or CD137 mAb compared with control mAb, PD-1/CD137 mAb compared with control and single mAb. </p