Figure 2.

type (I)IFN activation in immune infiltrating cells is necessary for early DMXAA-induced cell death and immune cell recruitment. A. IFNβ and IFNα gene expression was upregulated early after DMXAA injection in PyMT tumor bearing mice. B. Ifnr-1 ^−/− mice (C57Bl6/J) transplanted with the TC1 tumor cell line and treated or not with DMXAA were used to determine the importance of IFN type I signaling in host cells in DMXAA‐induced tumor regression. In WT mice, a single injection of DMXAA is sufficient to induced cell death and neutrophil recruitment in TC1 tumors, whereas in Ifnr-1^−/− mice, DMXAA fails to induce cell death and neutrophil recruitment. C. Upregulation of IFNβ and IFNα gene expression was abrogated in Ifnr-1 ^−/− mice treated with DMXAA, compared with wild type littermate. n n = 6 tumors, x = 2 independent experiments. One-way Anova was used for the statistics.