Figure 3

IL-18 induces activation of T effector cells, restricts ascites accumulation and prolongs survival of ID8-Vegf tumor bearing mice. (A) IL-18 does not have a direct cytotoxic effect on ID8 tumor cells. ID8 tumor cells (5 × 10⁵) were cultured for 48 hours in media containing IL-18 in a wide range of concentrations (0-1000 ng/ml), harvested, and viable cells counted after staining with Trypan blue. Results are means ± SEM of 3 experiments. (B) IL-18 induces activation of T effector cells. CD69 expression on CD3⁺ CD8⁺ cells isolated from the spleen of ID8-Vegf tumor bearing mice treated with saline or IL-18 (10 μg/day s.c for 20 days, starting 10 days after the tumor challenge). The bars are mean ± SEM of the CD69 expression in CD3⁺ CD8⁺ cells from spleens of 5 mice treated with IL-18 as above and 5 mice treated with saline. (C) Antitumor properties of IL-18 in C57BL/6 mice. IL-18 significantly restricts ascites accumulation as depicted by increase in the animal weight. The asterisks show data points were the difference between the groups is significant (Student's test, P < 0.05). (D) IL-18 significantly prolongs the survival of ID8-Vegf tumor bearing mice (P < 0.05). Control n = 9, IL-18 treated n = 9.