Figure 4

PD-1 blockade restores anti-glioma immunity in Cl13 mice. (A) Experimental set-up of the survival study showing the timing of orthotopic glioma challenge and intraperitoneal injections of therapeutic antibodies in LCMV Cl13 infected B6 mice. (B) Survival after orthotopic tumor challenge was monitored for up to 120 days. Median survival times after CT2A challenge with anti-PD-1 Ab or its isotype IgG were 20 (n = 4) and 18.5 (n = 6) days, respectively and those after CT2A-gp33 challenge with anti-PD-1 Ab or isotype IgG Ab treatment were 93 (n = 6) and 19.5 (n = 6) days, respectively. Log-rank test was used to compare survival between anti-PD-1 Ab vs isotype IgG in CT2A-gp33 vs CT2A groups, *p < 0.05, ***p < 0.001, ****p < 0.0001. (C) Numbers of GP33-specific effector CD44⁺ CD8⁺ T cells in CT2A-gp33-bearing brains of Cl13 pre-infected mice, 7 and 13 days’ post-tumor challenge, after treatment with PD-1 antibody or control isotype.