Figure 3.

Protective effect of DTT-SP₄ or DTSP against tumor development after receiving two different CT26 cell doses in the tumor model. (A) Flow chart of immunization and tumor inoculation. (B–G) Mice were immunized with Alum and CpG formulated DTSP, DTT-SP₄, FD^mut, or DTT, three times at 10-day intervals. Mice received two different doses of CT26 cells s.c. into the right flank 1 week after the third administration of the vaccine. (B–D) Female BALB/c mice (n = 5–8) were inoculated with 3 × 10⁵ CT26 cells/mouse. (B) Tumor volumes were determined in individual mice and calculated for each group. Data are means ± SD. Student's t-test. Mice were sacrificed on day 23 after tumor challenge. Tumors weights were measured (C) and the tumor inhibition rates were evaluated (D). (E–G) Immunized mice were challenged with CT26 cells (1 × 10⁵ cells/mouse). (E) Tumor growths were monitored every 2–3 days after the tumors were palpable and were presented as tumor volume (mm³). Data are means ± SD. ns, not significant, ^****p < 0.0001, ns, not significant, Student's t-test. (F) The proportion of tumor-free mice was plotted at different time points after tumor injection. (G) Percent survival was plotted by Kaplan–Meier method, and log-rank (Mantel–Cox) test was used to calculated the p-value. ^**p < 0.01, ^****p < 0.0001, ns, not significant.