Cationic polymers for enhancing CpG oligodeoxynucleotides-mediated cancer immunotherapy

Abstract Unmethylated cytosine-phosphate-guanosine (CpG) oligodeoxynucleotides (ODNs) as an adjuvant can activate innate and adaptive immune responses and simultaneously produce a large number of proinflammatory cytokines and up-regulate costimulatory molecules to treat cancer, allergy, asthma and infectious diseases. Polycationic biomaterials as delivery system can bind to CpG ODNs through electrostatic mechanism and overcome challenging requirements of CpG delivery including low cellular uptake efficiency, short half-life and quick release time and ease to be degraded by DNA enzyme (Dnase). This review provides new developments for the immunizing research of CpG ODNs and also focuses on cationic polymers for enhancing CpG-mediated cancer immunotherapy, together with brief discussions and perspectives for the future research direction.