library_construction_protocol: Transcriptomes of DivisionRecorder modified and unmodified OT-I memory T cells were obtained in two independent experiments, comprising 11 mice in total. Experiment 1 included 3 mice containing DR+ memory T cells (mouse 1-3), which were processed in a single batch. Experiment 2 included 4 mice containing DR+ memory T cells (mouse 4-7) and 4 mice containing unmodified memory T cells (mouse 8-11), which were processed in two separate batches (batch 1: mouse 4+5 and mouse 8+9, batch 2:  mouse 6+7 and mouse 10+11). Spleens of DivisionRecorder+ OT-I T cell recipient mice (n=7) or unmodified OT-I T cell recipient mice (n=4) were harvested >85 days post-infection. Splenocytes were stained with fluorochrome-conjugated antibodies directed against CD8, CD45.2 and Vβ5, to allow purification of transferred cells by FACS. DR+ cells were subsequently FACS purified based on their expression of RFP and GFP. Following the isolation of DRGFP and DRRFP memory T cells by FACS, obtained cell populations were barcode-labeled with distinct anti-mouse TotalSeq Hashtag antibodies, and pooled, with an equal number of cells from each mouse to form the total pool of cells for scRNA-sequencing. If the amount of sorted DRRFP cells was limited from a single sample, it was pooled together with another DRRFP sample to reduce cell loss during cell hashing. Single-cell RNA isolation and library preparation was performed according to the manufacturer's protocol of the 10X Genomics Chromium Single Cell 3' kit, and the cDNA library was sequenced on a NextSeqTM 550 Sequencing System (Illumina). Library preperation was performed in according the manufacturer's protocol of the 10X Genomics Chromium Single Cell 3' kit (V3)