Irradiation and anti–PD-L1 treatment synergistically promote antitumor immunity in mice

High-dose ionizing irradiation (IR) results in direct tumor cell death and augments tumor-specific immunity, which enhances tumor control both locally and distantly. Unfortunately, local relapses often occur following IR treatment, indicating that IR-induced responses are inadequate to maintain antitumor immunity. Therapeutic blockade of the T cell negative regulator programmed death-ligand 1 (PD-L1, also called B7-H1) can enhance T cell effector function when PD-L1 is expressed in chronically inflamed tissues and tumors. Here, we demonstrate that PD-L1 was upregulated in the tumor microenvironment after IR. Administration of anti-PD-L1 enhanced the efficacy of IR through a cytotoxic T cell-dependent…

• BS
  Bristol-Myers Squibb
• NI
  National Institutes of Health

  Award: CA141975