We used an sgRNA lentivirus targeting the randomly selected ANPEP gene to assess the capacity of this cell line for gene editing (Supplementary Fig. 2a), and found that gene-editing activity tended to be stable ~6–10 days post-infection of the sgRNA-harboring lentivirus in PK-15-Cas9 cells (Supplementary Fig. 2b). The gene discussed is ANPEP; the disease is infection.