Immunology and Biotherapies

Here, we investigated whether intratumoral injection of a foreign immunodominant peptide (GP33) and the adjuvant CpG into tumors following cisplatin chemotherapy could lead to potent antitumor effects and antigen-specific cell-mediated immune responses. We observed that treatment with all three agents produced the most potent antitumor effects compared to pairwise combinations. Moreover, treatment with cisplatin, CpG and GP33 was able to control tumors at a distant site, indicating that our approach is able to induce cross-presentation of the tumor antigen. Treatment with cisplatin, CpG and GP33 also enhanced the generation of GP33-specific and E7-specific CD8+ T cells and decreased the number of MDSCs in tumor loci, a process found to be mediated by the Fas–FasL apoptosis pathway. The treatment regimen presented here represents a universal approach to cancer control.