Fig. 5.

Antitumor effects of anti-CD40/CpG therapy in vivo are accompanied by the activation of tumor-associated PEC. C57BL/6 mice were injected i.p. with 10⁵ B16 cells. Anti-CD40/CpG treatments were administered on day 4/7, 11/14, and an additional injection of anti-CD40 was given in some experiments on day 18. Control mice received rat IgG and PBS, respectively. a The mice were followed for survival. The results of two combined experiments are shown (n = 16 mice per group). b Photographs of representative mice showing peritoneal tumor loads were taken on day 14 post B16 tumor cell injections; a naïve mouse is shown for comparison. The peritoneal tumor appears hemorrhagic. c Percentage of CD11b⁺Gr-1⁺ cells, as well as Ly6G⁺ and Ly6C⁺ cells, are shown (mean ± SEM, 3 mice per group). d–f Tumor-bearing mice were treated with anti-CD40/CpG on days 4/7 and 10 (d) or on days 11/14 (e, f) post tumor cell implantation. PEC were isolated on day 14 (d) or 15 (e, f), and adherent cells were tested for NO production (d, e). Dashes signify values below detection limit. The antitumor effect was determined by the percentage of B16 tumor cells (CD45⁻ PEC) using flow cytometry (f). Mean ± SEM of 4 mice per group. * p < 0.001