Preparation of Multifunctional Liposomes as a Stable Vaccine Delivery-Adjuvant System by Procedure of Emulsification-Lyophilization.

Liposomes have been proven to be useful carriers for vaccine antigens and can be modified as a versatile vaccine adjuvant-delivery system (VADS). To fulfill efficiently both functions of adjuvant and delivery, the liposomes are often modified with different functional molecules, such as lipoidal immunopotentiators, APC (antigen-presenting cell) targeting ligands, steric stabilization polymers, and charged lipids. Also, to overcome the weakness of instability, vaccines are often lyophilized as a dry product. In this chapter the procedure of emulsification-lyophilization (PEL) is introduced as an efficient method for preparing a stable anhydrous precursor to the multifunctional liposomes which bear dual modifications with APC targeting molecule of the mannosylated cholesterol and the adjuvant material of monophosphoryl lipid A. The techniques and procedures for synthesis of APC targeting molecule, i.e., the mannosylated cholesterol, and for characterization of the multifunctional liposomes are also described.