Liposome-mediated malaria vaccine development: More than a tour de force

The introduction of vaccine technology has facilitated an unprecedented multi-antigen approach to develop an effective vaccine against complex systemic inflammatory human malaria (Plasmodium falciparum). The capacity of multi subunit DNA vaccine encoding different stage Plasmodium antigens to induce CD8⁺ cytotoxic T lymphocytes and interferon-responses in mice, monkeys and humans has been observed. The cytotoxic T cell responses are categorically needed against intracellular hepatic stage and humoral response with antibodies targeted against antigens from all stages of malaria parasite life cycle. As genetic vaccination is capable of eliciting both cell mediated and humoral immune responses, the key to success for any DNA vaccine is to design a vector able to serve as a safe and efficient delivery system. This has encouraged development of non-viral DNA-mediated gene transfer techniques such as liposome, virosomes, microsphere and nanoparticles. The efficient and relatively safe DNA transfection using lipoplexes makes them an appealing alternative for gene delivery. In addition, liposome entrapped DNA has been shown to enhance the potency of DNA vaccines, possibly by facilitating uptake of the plasmid by antigen- presenting cells (APC). The control of residual non-adaptive immune effecters (mainly wandering macrophages and polymorphonuclears) by clodronate-loaded liposome in NSG immunodeficient mice further advocates their value for translational biomedical research.