Fig. 6.

PD-1 mAb blockade and CSF-1R inhibitors enhance vaccine-induced immune responses by distinct mechanisms. (A) Malignant gliomas lack a significant antitumor immune response in the nontreatment setting. (B) DC vaccination elicits an infiltrating TIL response, but is largely ineffective due to inactivation of TILs via the PD-1/PD-L1 signaling mechanism. (C) Treatment with CSF-1Ri alters the TIM population to become pro-inflammatory TIM (pTIM) and results in the expansion of the TIL population, increasing the potential for TIL-tumor cell interaction and tumor cytolysis. (D) While PD-1 mAb treatment does not increase the TIL population over what is generated by DC vaccination, it does promote activation of TILs and subsequent tumor cytolysis. (E) PD-1 mAb and CSF-1Ri together promote the expansion and activation of the DC vaccine-generated TIL population such that there is a maximal tumor cytolysis.