Figure 6.
Comparison of the antitumor effects of Synco-2D and Synco-B18R against Hepa1-6 and LL/2 tumors. (a) Hepa1-6 cells were infected with either Synco-2D (closed circles) or Synco-B18R (closed squares) at 1 pfu/cell. Cells were harvested at the indicated time and virus titer was determined by plaque assay. (b) Hepa1-6 cells were infected with either Synco-2D or Synco-B18R at 1 pfu/cell and were incubated in media without (open bars) or with IFN-α (closed bars) at a concentration of 500 U/ml. Cells were harvested at the indicated time for virus titration and the percentage of virus production was determined as described in Figure 2e. (c,d) Tumors were established in the right flank of immune-competent B6 mice by implanting 3 × 106 of Hepa1-6 cells (as shown in c) or 2 × 105 of LL/2 cells (as shown in d). Once the tumors reached an approximate size of 5 mm in diameter, the mice received intratumoral injection of either PBS as a negative control (closed diamonds), or 1 × 107 pfu of Synco-2D (closed circles) or Synco-B18R (closed squares). Tumor size was measured regularly as described in Materials and Methods. *P < 0.05 as compared with Synco-2D. IFN, interferon; pfu, plaque-forming unit; PBS, phosphate-buffered saline.