To investigate the possible impact of IL-9 expression on virus cytotoxicity in vitro, MC38-luc cells were infected with vvDD-IL-9 or the control virus vvDD at MOIs of 0, 0.05, 0.1, 0.5, 1, or 5, respectively, and the cell viability was measured 48 h after infection. This evidence concerns the gene IL9 and infection.