library_construction_protocol: After CD8+ T cells were isolated from spleen, cells were pooled into two samples (sample 1: 2 mice, sample 2: 3 mice). The following cells were then sorted: (1) live CD8b+ CD44+ GFP- CD45.1+, (2)  live CD8b+ CD44+ GFP- CD45.1+ CD45.2+, (3)  live CD8b+ CD44+ GFP- CD45.2+. Cells were counted and loaded onto the Chromium Controller (10X Genomics) for a target recovery of 6,000 single cells per sample. Library was performed according to the manufacter's instructions (single cell 3' v3 protocol, 10x Genomics).