Endogenous viral elements constitute a complementary source of antigens for personalized cancer immunotherapy

We present a pipeline, ObsERV, for the design of personalized cancer immunotherapies based on epitopes derived from endogenous retroviral elements (EVEs). We show that EVE-derived peptides are presented as antigens on tumors and can be predicted by ObsERV. Preclinical testing of ObsERV demonstrates elicitation of poly-functional CD4+ and CD8+ T-cell responses as well as long-term tumor protection and persistence of the responses. Murine tumors (B16F10 and CT26) were grown and harvested for RNA-seq. RNA-seq was leveraged to design EVE based vaccines using the ObsERV pipeline.