ABSTRACT
@#Objective: To investigate the role of CpG ODN (CpG oligodeoxynucleotide) adjuvant in enhancing the anti-bladder cancer response induced by MAGE-3 (melanoma antigen gene -3) antigen and its molecular mechanism. Methods: Mononuclear cells were isolated from HLA-A2 type peripheral blood of healthy donors by Ficoll method to prepare mature DC by conventional means. DC surface markers were detected by flow cytometry. MTT assay was used to detect the promotion effect of DCs sensitized by different means (MAGE-3, CpGODN, MAGE-3+CpG ODN, irrelevant control antigen) on the proliferation of T lymphocytes and the killing effect of CTL on BIU-87 tumor cells. The tumor mass of nude mice bearing BIU-87 bladder cell xenograft were examined on Day 7 and 11 after CpG ODN+MAGE-3 sensitized DC treatment. The expression of Bcl-2/Bax protein was detected by Western blotting while the proliferation level of xenograft cells was detected by MTT assay. Results: DCs sensitized by CpG ODN combined with MAGE-3 antigenic peptides could promote the proliferation of T lymphocytes and significantly enhance the killing effect of CTLon target BIU-87 cells (P< 0.05). Compared with other sensitized DCs, in vivo experiments showed that 7 and 11 days after treatment, both the tumor volume and weight were significantly reduced (all P<0.05), and the proliferation ability of xenograft tumor was decreased (P<0.05). Compared with other sensitization means, CpG ODN+MAGE-3 especially exhibited obvious inhibitive effect on tumor growth on Day 11, and significantly promoted the proliferation of splenic monocytes of tumor bearing mice (P<0.01); moreover, Bcl-2 expression in xenograft tissues significantly decreased（P<0.01）while Bax expression significantly increased（P<0.05 or P<0.01）on Day 3 after treatment. Conclusion: CpG ODN can promote the inhibitory effect of MAGE-3 sensitized DC on bladder cancer BIU-87 cells, which will provide experimental basis for clinical application of DC vaccine in bladder cancer treatment.