Intranasal DNA Vaccine for Protection against Respiratory Infectious Diseases: The Delivery Perspectives

Xu, Yingying; Yuen, Pak-Wai; Lam, Jenny Ka-Wing

Rosada et al. developed another liposome-based formulation of DNA vaccines against TB [176] . The non-toxic, cationic liposome, EPC/DOPE/DOTAP (Egg phosphatidylcholine/1,2-dioleoyl-snglycero-3-phosphoethanolamine/1,2-dioleoyl-3-trimethylammonium-propane) was used. Plasmid DNA encoding the 65 kDa mycobacterial hsp65 was either entrapped inside or complexed with the cationic liposomes, and the intramuscular and intranasal routes of administration were compared in mice. When administered intramuscularly, both liposomal formulations were ineffective in preventing tuberculosis infection in mice even after two doses. On the contrary, the complexed liposomal formulation of DNA vaccine was able to offer protection against infection even after a single dose, with a significant reduction of colony forming unit (CFU) in lungs after the immunized mice were challenged with Mycobacterium tuberculosis. However, four doses of intranasal administration of naked DNA vaccines failed to offer any protection. The authors reasoned that the intranasal vaccination enhance the immune response by stimulating the mucosal immunity, but the naked DNA failed to cross the mucosal barriers in the nasal cavity, demonstrating the importance with the use of delivery carrier for intranasal DNA vaccination.