Figure 4.

Anti-tumor Activity of VACV D9- and D10-Deficient Mutants in Human Tumor Xenografts in Immunocompromised Mice

HepG2 human HCC cells were injected (1 × 10⁷) s.c. into the flank of 8-week-old, female athymic, BALB/c nude mice. When tumors reached approximately 50 mm³ (approximately 7 days after HepG2 inoculation), they were directly injected on days 0, 3, 6, and 9 (indicated by downward black arrows) with 1.0 × 10⁶ PFU of D10-deficient (ΔD10) VACV (N = 10 mice), 1.0 × 10⁶ PFU of D9-deficient (ΔD10) VACV (N = 10 mice), or an equivalent volume of virus-free control preparation (mock) from uninfected cells (N = 10 mice). Tumors were measured on the indicated days, and the average normalized values reflecting relative tumor size on each day were plotted. Initial tumor volume immediately before treatment was normalized to a relative size of 1.0. Days on which the individual, moribund animals in the ΔD9 or ΔD10 treatment groups were sacrificed are indicated by symbols below (black + for ΔD9) or above (gray o for ΔD10) the respective data points. Error bars indicate SEM. p values were obtained by multiple t test. Gray * above the mock-treated line indicates comparisons of mock versus ΔD10. Black * below the mock-treated line indicates comparisons of mock versus ΔD9. **p < 0.05; ***p < 0.005.