Growth of HSVB7.1 or HSVlac amplicon-transduced EL4 cells and parental EL4 cells injected contralaterally in C57BL/6 mice. EL4 cells were infected ex vivo at an estimated MOI of 1 with either HSVB7.1 (A; mice no. 1 through 5) or HSVlac virus (B; mice no. 6 through 10). Viable transduced EL4 cells (10⁶) were implanted SC on one side of the hind limb of the C57BL/6 mice, and parental (nontransduced) EL4 cells (10⁶ cells/per mouse) were implanted on the contralateral hind limb. Tumor diameter was measured and expressed in millimeters. Tumor size in individual animals is shown.