Fig. 1.
Antitumor immunity induced by administration of ESCs. a Scheme of ESCs immunization and tumor inoculation. Mice in the vaccine group received subcutaneous 1 × 106 pre-irradiated ESCs vaccination three times at a 1-week interval, and 1 week after the third time of vaccination, 1 × 106 LLCs were inoculated subcutaneously. Mice in the treatment groups 1 and 2 also received subcutaneous 1 × 106 pre-irradiated ESCs immunization three times at a 1-week interval, at 2 and 5 days after the tumor challenge, respectively. b After the inoculation of 1 × 106 LLCs, tumor size of all groups was measured using a digital caliper and tumor volumes were calculated. The results indicated statistical difference in tumor size between the vaccine and control group from day 5 on (p < 0.05, and p < 0.01 from day 7 on), between the treatment groups and control group (p < 0.05) from day 7 on, and between the treatment groups 1 and 2 from day 9 on. c At the end of the experiment, all mice were killed under anesthesia and tumors were excised and weighed. The results of tumor weight suggested that there was significant difference between the vaccine and control group (p < 0.01), between the treatment groups and control group (p < 0.05), and between the treatment groups 1 and 2 (p < 0.05). d Tumor formation time of the control group and treatment groups. The difference in tumor formation time between the control group and treatment group 1 was highly significant statistically (p < 0.01). Error bars denote SD