Figure 4.

FTS-PEI nanocomplex-mediated anti-tumor immunity, antigen presentation, and epitope spreading

(A) PBS, pcDNA/FTS-PEI, free p-ovalbumin (pOVA), and pOVA/FTS-PEI were injected locally (intratumor) to B16F10-OVA (local tumors)-bearing mice once every 6 days for three times. Tumor growth was monitored once every 2 days. (B) Re-challenged tumors (distant tumors) were established via inoculation of tumor cells at the contralateral side after the 3^rd vaccination of the primary tumors, and tumor growth in both groups were monitored. Values reported are the mean ± SEM, n = 5. p values were generated by one-way ANOVA using the Tukey test for multiple comparisons. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001. (C) SIINFEKL-H2K(b) presentation by B16F10-OVA tumors treated with pOVA/FTS-PEI or PBS. Cells were stimulated with recombinant mouse IFN-γ (10 ng/mL) overnight to induce OVA surface expression. MFI, mean fluorescence intensity. Data are presented as the mean ± SEM, n = 5. p values were generated by two-tailed Student’s t test. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001. (D) CD8⁺ T cells were isolated from B16F10-OVA tumors treated with PBS, pcDNA/FTS-PEI, free pOVA, or pOVA/FTS-PEI and co-cultured with B16F10 or MC38 for 6 h. Tumor cells were collected afterward for flow cytometry analysis for CFSE intensity. Data are presented as the mean ± SEM, n = 3. p values were generated by two-tailed Student’s t test. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001. (E) CD8⁺ T cells were isolated from B16F10-OVA tumors treated with PBS, pcDNA/FTS-PEI, free pOVA, or pOVA/FTS-PEI and co-cultured with B16F10 or MC38 for 6 h. Culture medium was collected, and the level of IFN-γ in the supernatant was measured by ELISA.