Ablative Radiotherapy Synergizes With Protein Vaccination to Upregulate Systemic Dendritic Cell Function Within Non-Draining Lymph Nodes

Ablative RT delivered with soluble antigen and Poly I:C adjuvant results in increased systemic function of cDC1 compared to vaccination or RT alone. This experimental system reveals that radiotherapy synergizes with immunomodulation to increase systemic antigen uptake and processing by the DC population required for priming of functional anti-tumor immunity. This work has implications regarding how RT to a single lesion may facilitate priming or reactivation of distal anti-tumor immune responses in metastatic cancer. Follow up studies are underway to elucidate the mechanism of this abscopal effect on DC function and evaluate whether local radiotherapy results in increased tumor associated antigen uptake and presentation at distant sites.