Fig. 6
ISAg activated NK receptor-expressing innate immune cells via DC-derived IL-12. a The percentages of NK (NK1.1+CD3−) and NKT cells (NK1.1+CD3+) among the total splenocytes from Yet40 B6 mice were plotted. b Yet40 B6 mice were treated via the oral route with ISAg (0.5, 1, 2, or 4 mg/injection) or PBS three times per week for 4 weeks. As a positive control, mice were injected (i.p.) with LPS (2 μg) once per week for 4 weeks. Intracellular productions of IFN-γ and TNF-α were analyzed in NK and NKT cells. c, d Yet40 and Yet40p35KO mice were treated via the oral route with ISAg (4 mg/injection) or PBS three times per week for 4 weeks; intracellular production of (c) IFN-γ and (d) TNF-α were then analyzed in NK and NKT cells. (e) NK1.1+ cells were isolated from total splenocytes of WT B6 mice treated with ISAg (4 mg/injection), PBS, or LPS [2 μg/injection (i.p.)]. The percentages of NK and NKT cells among the purified NK1.1+ cells were measured using flow cytometry. f Purified NK1.1+ cells were co-cultured with CFSE-labeled B16 tumor cells (2 × 104) at the indicated E:T ratios. After 10 h of co-culture, cytotoxicity was evaluated by calculating the percentage of 7-AAD+ (dead) cells, compared with the CFSE+ target cells. The mean ± standard deviation values are presented (n = 3 per group; Student’s t-test; *P < 0.05, **P < 0.01). Two-way ANOVA (genotype × treatment) revealed there was an interaction between these two factors (##P < 0.01)