Figure 1.

Anti-PD-1 mAb promotes tumor-specific CD8⁺ T cell proliferation in draining lymph nodes. (A–C) C57BL/6 mice were injected s.c. with MC38-OVA tumor cells (0.5 × 10⁶ cells). After 10 days, mice were treated or not with anti-PD-1 (250 µg, i.v.) either alone or anti-PD-1 in combination with FTY720 (20 µg for each injection). (A) Experimental setup. (B) Evolution of tumor volume between day 0 and day 10. (C) Mice survival. Statistical analysis was performed using a log-rank test. Compiled from two independent experiments with 10–12 mice per group. (D and E) Representative FACS contour plots and quantification of H2-K^b-OVAp tetramers⁺ among CD8⁺ T cells 5 days after treatment. Tumor-free mice were included as a control. Compiled from five independent experiments with 13–15 mice per group. (F–I) C57BL/6 mice were injected s.c. with MC38-OVA or EG7 tumor cells. After 10 days, mice were adoptively transferred with naïve CTV-labeled OT-I CD8⁺ T cells and treated, or not, with anti-PD-1 mAb (250 µg, i.v.). (F) Experimental setup. (G–I) OT-I CD8⁺ T cell proliferation was assessed on day 3 in the draining lymph node. (G) Representative histograms showing CTV dilution in OT-I CD8⁺ T cells. (H) Quantification of OT-I CD8⁺ T cell replication index in lymph nodes from mice bearing MC38-OVA. Anti-PD-1 mAb-treated mice were compared with PBS- or isotype-injected mice with similar results. Compiled from five independent experiments with 12–19 mice per group. (I) Absolute numbers of OT-I CD8⁺ T cells in tumor-draining lymph nodes were assessed 3 days later. Compiled from four independent experiments with a total of 10–12 mice per group. (J and K) Quantification of OT-I CD8⁺ T cell (J) replication index and (K) absolute numbers in tumor-draining lymph nodes from mice bearing EG7. Compiled from three independent experiments with a total of seven to nine mice per group. Statistical analyses were performed using t tests (E, I, J and K) or two-way ANOVA (H). *, P < 0.05; **, P < 0.01; ***, P < 0.001.