CD8 T cells were FACS-sorted into FCS containing tubes and after sort 10% DMSO were added, mixed and stored at -80°C until all samples were collected. Profiling of Chromatin was performed by ATAC-seq. Cells were thawed and washed in cold PBS and lysed. After cell lysis, transposition was performed at 42ºC for 45 min. After purification of the DNA with the MinElute PCR purification kit (Qiagen), material was amplified for 5 cycles. Additional PCR cycles were evaluated by real time PCR. Final product was cleaned by Ampure Beads at a 1.5x ratio. Libraries were sequenced on a Hiseq 2500 1T in a 50bp/50bp Paired end run, using the TruSeq SBS Kit v3 (Illumina).