Figure 2.

Irradiation and PD-1 blockade therapy induce an additive effect in a model of metastatic melanoma of the brain. A. Graphical representation of the experimental setup and treatment schedule for head irradiation experiments. B. Mice receiving concomitant D4M tumors implanted intracranial and in the flank were treated with IgG or anti-PD-1 antibody followed by four doses of 2 Gy irradiation to the head according to the experimental plan in A. Mice were then followed for 25 days post irradiation, and survival is indicated by the Kaplan-Meier plot. C. Growth in flank tumor size as measured by volume for the indicated groups is represented. On day 20, IVIS bioluminescence imaging of the animals was performed and graphs represent the intensity of luminescence of flank tumors (D.) and brain tumors (E.). Representative bioluminescence images at this time point. (F.) *p < 0.05 and **p < 0.01 for comparisons between the indicated groups.