Liposomal vaccination system

Development of a Liposomal Vaccination System for Immunity-Modulating Antitumor Therapy... 

In Vitro Characterization and Optimization of the Liposomal Vaccine System by FACS Analysis... 

Influence of the Liposomal Vaccine System on the Number of Activated Circulating Cytotoxic T Cells... 

Test for the Prophylactic and Therapeutic Efficiency of the Liposomal Vaccine System... 

Therefore, liposomes, and also nanoparticles, may allow for the development of needle-less vaccination systems. Studies on mice inoculated with influenza DNA vaccine complexes with liposomes and SLN already demonstrated a clear T-cell (predominantly Thl-type) response. Therefore, the immune response appears to be mediated by Langerhans cells, which is the immune competent cell in the skin (for review, see [65]). 

Aramaki, Y., Fujii, Y., Yachi, K., Kikuchi, H., and Tsuchiya, S. (1994), Activation of systemic and mucosal immune response following nasal administration of liposomes, Vaccine, 12,1241-1245. 

Adjuvants are substances which can modify the immune response of an antigen (139,140). With better understanding of the functions of different arms of the immune system, it is possible to explore the effects of an adjuvant, such that the protective efficacy of a vaccine can be improved. At present, aluminum salt is the only adjuvant approved for use in human vaccines. New adjuvants such as QS-21, 3D-MPL, MF-59, and other liposome preparations are being evaluated. Several of these adjuvants have been in clinical trial, but none have been approved for human use. IL-12 has been proposed as an adjuvant which can specifically promote T-helper 1 ceU response, and can be a very promising adjuvant for future vaccine development. 

Liposomes have been widely used as model membranes and their physicochemical properties have therefore been studied extensively. More recently, they have become important tools for the study of membrane-mediated processes (e.g., membrane fusion), catalysis of reactions occurring at interfaces, and energy conversion. Besides, liposomes are currently under investigation as carrier systems for drugs and as antigen-presenting systems to be used as vaccines. 

Thus, liposomes—with or without adjuvants—have a potential as antigen delivery systems. No clear insights exist on how to prepare liposome-based vaccines with optimum immunological properties by rationale instead of by trial and error. Therefore, much basic work is needed to unravel the mechanisms involved. 

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