The Investigation Of The Adjuvant Effects Of Two Immunological Stimulators-CpG ODN And Poly(I∶C)

Objective:poly(I:C)(Double-stranded RNA, dsRNA) and Cp60DN(unmethylated CpGoligodeoxynucleotides) in DNA are pathogen-associated molecular patternsof viruses and bacteria that activate innate immunity. To examine whetherdsRNA and CpG DNA could be combined to provide enhanced stimulation ofinnate immunological response and adaptive immunological response,splenocytes were stimulated with poly(I:C) and CpG ODN. To detect if thereis synergy effect between the two immunological stimulator as adjuvantof peptide, C57BL/6 were immunized with MUCl plus poly(I:C)/CpG-ODN orthe combination of the two agents as adjuvant.Methods:In vitro, murine splenocytes were incubated with polyI:C alone, CpG-ODNalone or the combination of the two agents. Supernatant were harvested,and interleukin (IL)-12p40, tumor necrosis factor-α(TNF-α), IFN-γandIL-4 measured by ELISA. In vivo, C57BL/6 mice received s.c. and i.p.injection with MUC1 peptide, alone or in combination with CpG ODN, polyI:C,CpG ODN+polyI:C or PBS as control. The subtype of T cell was analysedby Flow Cytometry. Tumor protection assay was proceeded. Afterimmunization, mice were challenged s.c. with tumor cells and tumor sizewas monitored. Then the mean diameter was plotted over time.We investigated the utility of MUC1 along with CpG ODN, poly(I:C) or CpGODN+ poly(I:C) for protection against MUel-expressing tumorigenic cellline using an animal model.Results:In vitro, combined treatments demonstrated synergy for interleukin(IL)-12p40, and TNF-αproduction.In vivo, Treatment of mice with pie and CpG-ODN in combination resulted in enhanced number of CD4+T cells and CD8+T cells relative totreatments with either agent alone. Stimulation of mice with thecombination of pIC and CpG-ODN demonstrated synergism for serum TNF-α,IL-12p40 and IFN-γserum levels in mice that correlated with anenhanced antitumor response to experimental pulmonary metastases incomparison with treatments with pIC or CpG-ODN alone. CpG ODN+polyI:Ccoinjection with MUC1 showed a better suppression of tumor growth atprophylactic levels.Conclusions:In conclusion, the combination of poly(I:C) and CpG ODN as the adjuvantof peptide MUC1, resulted in an enhanced innate and adeptive immuneresponse that could be used for tumor vaccination or immunotherapy. Thecombination of poly(I:C) and CpG ODN could be a potent adjuvant. These datasuggest that CpG ODN+poly(I:C) codelivery with TAA could be an effectiveapproach to induce stronger protective immune responses as a possibleprophylactic strategy for cancer.