A long-lasting dendritic cell DNA vaccination system using lysinylated amphiphiles with mannose-mimicking head-groups.

Dendritic cells (DCs) pulsed/transduced with tumor-associated or viral antigens have shown promise in combating cancer and infectious diseases. Despite significant progresses, development of a biologically safe DC-based genetic immunization (DNA vaccination) system capable of providing truly long-lasting protective immunity remains a significant scientific challenge. Here we show that immunization with autologous DCs pre-transfected with electrostatic complexes (lipoplexes) of a plasmid DNA encoding melanoma tumor associated antigen and liposomes of two lysinylated cationic amphiphiles with mannose-mimicking quinic and shikimic acid head-groups provides long-lasting (300 days post tumor challenge) protective immunity with significant memory response (more than six months after the second tumor challenge) in more than 80% immunized mice. The presently described non-viral ex vivo DC-transfection system may be exploited in inducing long-lasting immune response in DC-based genetic immunization.