CD200R antagonist blocks CD200 induced immune suppression enhancing survival. A and B. Tumor bearing mice were vaccinated with OVA + Poly:ICLC +/- antagonist then analyzed for OVA-specific T cells and cytokine production following in vitro restimulation with OVA. Tumor bearing mice were vaccinated with saline (n = 10), tumor lysate + CpG (n = 10) or tumor lysate + CpG + antagonist 6059 (n = 10). C. Mice were imaged weekly for tumor growth and (D) followed for survival. Error bars are ± SEM, *p < 0.05, **p < 0.001 was determined by one-way ANOVA, post hoc analysis by Dunn’s multiple comparison test, log-rank analysis was used for survival. Error bars are ± SEM, statistical significance was determined using an unpaired T-test, *p < 0.05, ** p < 0.001.