Abstract: Provided herein are methods and compositions for modulating T-cell activity by incubating a CD8 T cell with a signal 3 cytokine, such as IL-12. Incubation of naïve CD8 T cells, particularly, with a signal 3 cytokine can acquire long-lived memory associated gene expression characteristic of the stem cell memory subset of CD8 T cells. Further, incubation with signal 3 cytokines can induce changes to the epigenetic profile of naïve CD8 T cells that are more characteristic of bona fide Tscm cells than in vitro generated cells using traditional differentiation protocols. On account of epigenetic profiles being preserved during in vivo homeostasis, signal 3 cytokines such as IL-12 can be used to engineer a T cell population with the desired epigenetic profile that maintains effector functions and proliferative capacity.

Abstract: Provided herein are methods and compositions for modulating T-cell activity by altering DNA methylation status. Altering the methylation status of CD8+ T cells can prevent T-cell exhaustion and maintain effector functions during sustained antigen exposure. The methods and compositions can be used to treat symptoms of chronic infections and cancer. Further, the methods and compositions relate to predicting T-cell activity by measuring the methylation status of specific memory cell methylation markers and using the markers to identify and separate populations of CD8 T cell having desired T cell activity. The memory cell methylation markers can further be used to identify subjects with chronic infections or cancer that would benefit from personalized therapy, including immune checkpoint blockade therapy.