Figure 4.

The role of host immune system on the antitumor efficacy of vaccinia virus (VV) vectors. (a) TC-1 and (b) LKRM2 tumors were inoculated into NSG immunodeficient mice. When tumor reached ~200 mm³, VV.Luc and vaccinia viral vector-expressing mIFNβ (VV.mIFNβ) were then injected into mice intratumorally and tumor size was monitored twice a week. The role of CD8⁺ cells on VV-mediated antitumor effect was also investigated by inoculating (c, e) TC-1 and (d, f) LKRM2 cells into syngeneic immunocompetent mice. Intraperitoneal injection anti-CD8 antibody was used to deplete CD8⁺ cells. The timepoint chosen for the comparison was 10 days post-VV administration. The values on the bar charts are expressed as the mean + SEM (n = 6/group). *Denotes for significant induction of interferon-β (IFNβ) above the untreated control (P < 0.05), which was analyzed with Student's t-test.