library_construction_protocol: Naïve CD8+ T cells were FACS sorted by staining for CD8, CD4, CD45RA, CD45RO and Viability Dye. Cells were sorted into PBS + 2% BSA  + 2mM EDTA. Cells were placed in Trizol and RNA was purified following the manufacturer's instructions, with the addition of a chloroform extraction, GlycoBlue addition when precipitating, and a second wash of the pelleted RNA in 70% ethanol. RNA integrity was confirmed on a Fragment Analyzer. Libraries were prepared by the TREx core at Cornell University as follows: RNAseq libraries were generated with the non-directional NEBNext Ultra II RNA Library Prep Kit (New England Biolabs) using 10 ng of total RNA that was initially polyA-selected.