FIG 12.
M2L deletion does not affect the transgene expression level in vivo. A total of 3 × 105 B16F10 murine tumoral cells was implanted subcutaneously in C57BL/6 mice. When tumor volume reached 20 to 100 mm3, 107 PFU of doubly (TK− RR−) or triply (TK− RR−M2L−) deleted vaccinia virus encoding firefly luciferase (VV-DD-Luc or VV-TD-Luc, respectively) was injected intratumorally (day 0) and then at days 3, 6, 9, and 13. At days 1, 2, 6, 9, 13, and 16, three mice/group were euthanized; their tumors were weighed and homogenized, and the luciferase activity was measured according to the recommendations of the provider (Promega) of the kit. The luciferase activity was reported for each time point as a mean of the three measurements. The dashed line represents the background of the luminescence determined from noninjected tumors. RLU, relative light units.