To investigate the role of p53 in influenza virus infectivity, we used the genome-editing technique CRISPR/Cas9-mediated knockout (15) to generate isogenic p53null cell clones from the influenza virus-susceptible lung cancer cell line A549, which carries the wild-type p53 alleles and is also widely used as a model cell line for influenza research. The gene discussed is TP53; the disease is influenza.