Combination treatment with PD-1 mAb and CSF-1Ri maximally enhances vaccination-induced immune responses in both murine glioma and ex vivo human GBM. (A) Murine GL261-hgp100 glioma cell (TC) cytolysis at 4 hours following co-culture of TC, Pmel-1 T cells, and TIMs FACS-subjected from intracranial tumor-bearing mice treated with DC vaccination. PD-1 mAb or CSF-1Ri were added to Pmel-1 T cells or TIM ex vivo, respectively (n = 4/ group) (***P < .001). (B) Mice were randomized into control (tumor-bearing, no treatment), DC vaccine, DC vaccine + PD-1 mAb, DC vaccine + CSF-1Ri, and DC vaccine + PD-1 mAb + CSF-1Ri treatment groups. Graph depicts comparison of survival using method of Kaplan–Meier (n = 6/group) (**P < .01, ***P < .001, ****P < .0001) (P values indicate statistical difference from no treatment control unless otherwise indicated). (C) Human GBM tumor cell (TC) cytolysis over time following co-culture of TC, TIL, and TIM for representative GBM patient. PD-1 mAb or CSF-1Ri were added to autologous TIL or TIM ex vivo, respectively. (D) Compilation of human GBM tumor cell (TC) cytolysis at 4 hours following co-culture of TC, TIL, and TIM. PD-1 mAb or CSF-1Ri were added to TIL and TIM ex vivo, respectively (n = 8 patient samples/group) (**P < .01, ****P < .0001).