Isolation of CD45+ cells and B220+CD11c+NK1.1+ cells

To collect tissue containing CD45⁺ cells, we digested mouse livers and lungs with 0.5 mg/ml of collagenase, 1 mg/ml of dispase and DNase at 37°C for 45 min. Cell suspensions were incubated with mouse CD45‐microbeads or NK1.1‐microbeads (MACS, Miltenyi Biotec, Auburn, CA), and the captured cells were used for in vitro culture or in vivo injection. We also isolated photoconverted CD45⁺ cells obtained from the KikGR‐Tg mice using CD45‐microbeads and further purified the cells with a fluorescent‐activated cell sorter (BD FACSJazz, BD Biosciences, MoFlo Astrios^EQ, Beckman Coulter, or S3e Cell Sorter, Bio‐Rad, Hercules, CA). These experiments using CD45‐microbeads are shown in Figs 1A–C and ​and5D5D and Appendix Table S2. To obtain B220⁺CD11c⁺NK1.1⁺ cells for culture and in vivo injection, we purified the cells with a cell sorter (MoFlo Astrios^EQ). For flow cytometric analysis, 0.5 μg of Abs per 10⁶ cells in 100 μl volume was used. The percentage in figures is explained in legends. The Zombie Green fixable viability kit (BioLegend) was used to detect dead tumour cells after incubation with B220⁺CD11c⁺NK1.1⁺ cells.