(A) Diagram representing the treatment timeline for panels B–E. 1×106 MC38 cells were injected subcutaneously in the right leg on day −14, and four different radiation schedules of two fractions of 8Gy were given either 0, 1, 4 or 10 days apart starting on day 0. α-PD-L1 (25μg) or isotype control (25μg) was given starting the day before each radiation dose and continuing for 2 doses after radiation. Arrow represents α-PD-L1 or isotype dose, lightning bolt indicates radiation dose.
(B–E) Mice were treated as described in (A) and as shown with arrows above the tumor curves. The same isotype control mice are shown in each panel for relative comparison, as all tumor curves in these panels were collected in the same experiment. Tumor volume was measured, and the results are presented as mean ±SEM, IR irradiation, ns not significant, ** p < 0.01, *** p < 0.001, n=7/group, representative of two independent experiments.