To investigate the possible impact of foreign gene expression on virus cytotoxicity, we infected MC38-luc, B16 and LLC cells with vvDD-IL-23 or control virus vvDD at MOIs of 0.05, 0.1, 0.5, 1, 5 or 10, respectively, and measured the cell viability 48 h after the infection. Here, IL23A is linked to infection.