Treatment of combined anti-PD-1/OX40 mAb induced tumor-specific long-lasting immunity against ID8 ovarian cancer.

<p>A, Mice (10 mice per group) transplanted i.p. with 1×10⁶ ID8 cells 10 day before were treated thrice with 200 µg of control, anti-PD-1, anti-OX40 and anti-PD-1/OX40 mAb at 4 days interval and overall survival of mice was recorded. B, Mean survival time of mice with tumor growth was calculated. C, The peritoneal tumor masses was weighed when mice were euthanized with each dot representing each mouse. D, Long-term surviving (90 days after first tumor challenge) mice (4 mice per group) from 2 mAb treatment group were rechallenged with ID8 cells given i.p. or s.c. or with syngeneic unrelated TC1 cells transplanted s.c., and then overall survival of mice was recorded. E, Mice (5 mice per group) treated with combined anti-PD-1/OX40 mAb were also injected with an anti-CD4, anti-CD8, anti-NK1.1, or control mAb with 500 µg of each mAb per mouse 1 day before and two days after tumor challenge followed by injection of 200 µg every 5 days thereafter for the duration of the experiments. Tumor-bearing untreated mice were as negative controls (UNT). Overall survival of mice was recorded. Data are representative of three independent experiments except for D and E, which was from one experiment. ***P<0.001, combined mAb vs control or single mAb treated mice in A-C; ***P<0.001, s.c. or i.p.ID8 vs s.c.TC1 in C; * P<0.05, control or NK1.1 vs UNT, CD4 or CD8 in D.