Potential use of CpG ODN for cancer immunotherapy

Tumor immunotherapy has advanced over the past century from the use of crude bacterial extracts such as Coley's toxins to the use of recombinant cytokines and now to the use of synthetic ligands to specific immune receptors such as the Toll-like receptors (TLR) which activate the vertebrate immune system through recognition of specific microbial components (pathogen-associated molecular patterns or PAMPs). Synthetic oligodeoxynucleotides containing immunostimulatory CpG motifs (CpG ODN) which act as ligands for TLR9 have been used successfully as tumor immunotherapy in animal models as well as in human clinical trials. This review describes the immune effects of CpG ODN, and their applications in immunotherapy of cancer.