Demethylation of cancer/testis antigens and CpG ODN stimulation enhance dendritic cell and cytotoxic T lymphocyte function in a mouse mammary model.

ABSTRACT

BACKGROUND: Cancer/testis antigens (CTAs) are ideal targets for cancer immunotherapy in virtue of their restricted expression profile in normal tissues. However, CTA-targeted immunotherapy has been rather disappointing clinical setting for CTAs are downregulated by cytosine-phosphate-guanosine (CpG) methylation in their promoter regions, so that tumor cells have low immunogenicity. METHODS: We reinduced mouse CTA P1A through demethylation process and generated P1A-specific cytotoxic lymphocytes (CTLs) by immunizing BALB/c (H-2(d)) mice with dendritic cells pulsed with a P1A-specific peptide and CpG oligodeoxynucleotide (ODN) immune adjuvant. RESULTS: We found that demethylation and CpG ODN immune adjuvant stimulation facilitated DC maturation and enhanced the allogenic capacity of P1A-specific CTLs against target cells both in vitro and in vivo. CONCLUSIONS: Our results suggested that CTA induction and immune adjuvant stimulation is a feasible strategy in cancer immunotherapy.