Fig. 7

Anti-tumor effects by ISAg were associated with boosted cytotoxicity of NK receptor-expressing innate immune cells. Yet40 B6 mice were treated via the oral route with ISAg (4 mg/injection) or PBS three times per week beginning 1 week after tumor injection and ending at 3 weeks. As a positive control, mice were injected (i.p.) two times per week beginning at 1 week after tumor injection until 3 weeks with α-GalCer (2 μg) dissolved in PBS. The mice were euthanized at day 21 after B16 tumor cell injection. The spleen and tumor tissues were excised from each mouse. a Representative photographs of a mouse from each treatment, 21 days after tumor injection (top row). Photographs of the tumors from each of the mice in the top row (bottom row). b The weights of the tumors from individual mice are presented mean ± standard deviation values (n = 5 per group; Student’s t-test; **P < 0.01). c, d On day 21 after injection, mononuclear cells were isolated from the tumors of mice in the indicated treatment groups using a Percoll gradient. c The absolute numbers of CD45⁺ cells per gram of tumor tissue were assessed using flow cytometry. d The frequencies of the NK and NKT cells among the CD45⁺ cells from the tumors were evaluated using flow cytometric analysis