ABSTRACT
THE VIROSOMAL VACCINE APPROACH Since their introduction the use of liposomes as a research tool has undergone an impressive evolution. Liposomes have become the preferred system for studying the reconstitution of membrane transport proteins and enzymes, the mode of action of ionophoric peptides and a variety of anaesthetics and other drugs (Brotherus et al., 1981). Thus liposomes have played an essential role in developing our current understanding of the structure and function of biological membranes in areas such as membrane fusion (Duzzqunes and Papahadiopoulos, 1983; Lüscher-Mattli and Glück, 1990; Tsurudome et al., 1992; Lüscher-Mattli et al., 1993), antigen-antibody interactions (Honegger et al., 1980; Hafeman et al., 1980), the complement system (Müller-Eberhard, 1988), blood coagulation (Bangham, 1961; Papahadiopoulos et al., 1962) and arteriosclerosis (Papahadiopoulos, 1974; Small and Shipley, 1974). During the early 1970s, liposome research went beyond basic membrane physics and into the area of therapeutic application, as a vector system for altering the tissue disposition of various macromolecules in vitro (Gregoriadis and Leathwood, 1971), and for introducing foreign macromolecules into cells in vitro (Papahadiopoulos, 1974). With these two new developments, liposome research bridges three different fields: biophysics, cell biology and medicine. To date the most successful examples of liposomal pharmaceutical products are those with doxorubicin (an antineoplastic drug) (Treat et al., 1990; Wälti and Glück 1993), amphotericin (an antifungal drug) (Lopez-Berestein, 1989; Davidson et al., 1991) and vaccines (hepatitis A vaccine) (Glück et al., 1992). Liposomal amphotericin and liposomal
hepatitis A vaccine (Glück et al., 1994) are the first formulations of liposomes to become licensed for clinical use.
