Figure 4.

RGO-PEG exerts potent antitumor efficacy against MC-38 colon carcinoma. (a–c) Prophylactic vaccine study. (a) Study design. C57BL/6 mice were vaccinated SC at the tail base with (1) PBS control; (2) RGO(CpG)-PEG; (3) RGO-PEG-Adpgk; (4) soluble CpG + Adpgk; and (5) RGO(CpG)-PEG-Adpgk, followed by MC-38 tumor cell challenge SC in the flank on day 40. Adpgk peptide and CpG doses were both 15 μg in all treatment groups. (b) Adpgk-specific CD8α⁺ T cells among PBMCs. (c) Tumor growth was measured over time and (d) overall survival curve. (e–h) Therapeutic vaccine study. (e) Study design. MC-38 tumor-bearing mice were vaccinated on day 7 as in (a). (f) Adpgk-specific CD8α⁺ T cells among PBMCs. (g) Tumor growth was measured over time and (h) overall survival curve. (i–p) MC-38 tumor-bearing mice were treated as in (i), and (j) IFN-γ ELISPOT assay was performed on splenocytes ex vivo restimulated with Adpgk peptide on day 20. In parallel, inguinal LNs (k, l) and tumor tissues (m–p) were analyzed for activated CD45⁺CD11c⁺CD86⁺ DCs (k, m), Adpgk-specific CD8α⁺ T cells (l, p), CD3⁺CD8α⁺ T cells (n), and CD3⁺CD4⁺ T cells (o) by flow cytometric analyses. Data represent mean ± SEM from a representative experiment (n = 5, a–h) or (n = 4, i–p) from three independent experiments (a–h) or two independent experiments (i–p). Data were analyzed by one-way ANOVA (j–p) or two-way ANOVA (b, c, f, g) with Tukey’s HSD multiple comparison post hoc test or log-rank (Mantel-Cox) test (d, h). * in (b) and (f) indicates statistical difference between groups 4 and 5. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.