FIG. 5.
Antitumor efficacy of 107 and 105 PFU of an antiangiogenic vaccinia virus in an immunocompetent mouse model. (A) BALB/c mice bearing subcutaneous tumors (three mice per group; two tumors per mouse) induced with Renca cells were injected intravenously with 107 PFU of replicating or UV-inactivated vaccinia virus. Tumor size was followed and plotted relative to the size before virus injection on day 1. Note that all mice in the mock and vvdd-luc-inactivated groups had to be killed because of large tumors that formed by days 9 and 11, respectively. (B) An additional four tumor-bearing and tumor-free BALB/c mice per group were injected intravenously with 107 PFU of the indicated virus, and organs were harvested and hematoxylin-eosin stained 3 days later. Spleens of all virus-injected mice showed accumulations of small round-shaped, dark blue-stained cells, indicating extramedullary hematopoiesis. Large pictures are at 40× magnification, and small pictures in the upper left corner are at 63× magnification. Arrows indicate additional sites of extramedullary hematopoiesis. (C) Serum cytokine concentrations for MCP-1, IFN-γ, RANTES, KC, and MIP-1α were measured at the indicated time points. (D) VEGFR-1-Ig concentrations in serum of the mice were assessed by ELISA. (E) An additional three BALB/c mice per group were intravenously injected with different concentrations of replicating or inactivated vvdd-VEGFR-1-Ig, and TNF-α, IL-6, and MCP-1 serum levels were measured. (F) In another experiment, tumor-bearing BALB/c mice (three mice per group; two tumors per mouse) were intravenously injected with 105 PFU of replicating or inactivated vaccinia virus. Rapid tumor growth required killing of all mice in the mock-treated and vvdd-luc-inactivated groups by day 9 and 11, respectively. Bars indicate standard errors.