Checkpoint blockade immunotherapy relies on T-bet but not Eomes to induce effector function in tumor infiltrating CD8+ T cells

Coinhibitory receptor blockade is a promising strategy to boost immunity against a variety of human cancers. However, many patients still do not benefit from this treatment, and responders often experience immune-related toxicities. These issues highlight the need for improved understanding of checkpoint blockade, but the T cell-intrinsic signaling pathways and gene expression profiles engaged during treatment are not well defined, particularly for combination approaches. We utilized a murine model of CD8+ T cell tolerance to address these issues. We used microarrays to examine the global transcriptional response of T cells rendered tolerant in vivo by encounter with tumor/self-antigen versus T cells activated in response to an immunogenic tumor. RNA isolated from naive Gag-specific T cells was compared to RNA isolated from T-cells transferred into B6 mice with established FBL tumor (immune) and from Alb:Gag mice (tolerant). Two days after T cell transfer, recipient spleen and lymph nodes were harvested and pooled. Transferred cells were then sorted based on CD8+ CD90.1+ CD69hi to a >96% purity using a FACSAria III (BD Biosciences). There were 3 biological replicates per condition.