Abstract 761: Comparison of different classes of CpG-ODNs to augment generation, proliferation and specific cytotoxicity of human epitope-peptide specific CTLs in vitro

Abstract

Abstract Three distinct classes of CpG- oligonucleotides (ODN) (CpG-A, CpG-B and CpG-C) have been identified based on differences in their structures and immune effect. So far, CpG-B is only applied for clinical treatments; however, it is still unknown which of the different CpG-ODN classes is most useful as adjuvant of human cancer vaccine therapy. In the present study, we examined the activity of these 3 types of CpG-ODNs to enhance the induction of human peptide-specific CTLs. In addition, we elucidated the effect of CpG-ODNs on tumor antigen epitope peptide-specific CTL clones to investigate the adjuvant mechanism of CpG-ODNs on peptide vaccine therapy. Our data showed that PDC activated by CpG-ODNs augmented induction of peptide specific CTLs. Importantly, CpG-A is superior to CpG-B and CpG-C in augmenting the generation, proliferation and cytotoxic activity of human peptide specific CTLs in vitro. Moreover, type-1 IFNs produced by PBMCs that were stimulated with CpG-ODNs accelerated the proliferation of peptide-specific CTL clones, and also directly augmented the peptide specific cytotoxicity of CTL clones through the up regulation of Granzyme-B. These data showed that IFN-α might play an important role for CpG-ODNs to induce the adjuvant effects in peptide vaccine therapy. In addition, because CpG-A induced high amount of type-1 IFNs, CpG-A might be the superior candidate for vaccine adjuvant than CpG-B or CpG-C. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 761. doi:10.1158/1538-7445.AM2011-761