ABSTRACT
Liposomes are versatile drug delivery systems that can be surface-modified with a variety of molecules that carry out a number of functions such as promoting the targeting of the vesicles to specific cell types and/or modulating their biodistribution and pharmacokinetic properties (e.g., polyethylenegly col (PEG)ylated liposomes). Targeting of liposomes, which represents a major issue to increase the specificity and efficiency of bioactive molecules delivery, has been a much-studied approach during these last decades (1-3). It involves, in most cases, the use of ligands that are recognized by receptors (over)expressed at the surface of target cells. These ligands, which are conjugated to the surface of liposomes according to well-established bioconjugation methods, are either small molecules, such as, e.g., folic acid or carbohydrate clusters that trigger receptor-mediated endocytosis, or proteins such as monoclonal antibodies that are directed against specific antigens.
Besides drug delivery, liposomes have also gained wide acceptance in other fields such as diagnostic imaging (4,5) and vaccines. In this chapter we will focus our attention specifically on the conjugation of peptides to liposomes. We will outline the major techniques involved, present some applications of liposomes-peptides constructs, and mainly discuss their use as vaccines.
