Liposomal Vaccines

Abstract

In the past decade, medical research made rapid advances in technologies associated with vaccine development, in particular molecular engineering and peptide synthesis. These new technologies opened the door to development of vaccines effective against newly emerging pathogens and even proteins or antigens that cause diseases of noninfectious origin. However, realization of the potential of subunit or peptide vaccines has been hampered by fundamental issues inherent in the presentation of these antigens to an immune system. In general, such vaccines fail to stimulate strong immune responses because they present antigens that (a) are not oriented in space or in the context of other surface proteins and molecules in the same way they are on the pathogen itself, (b) don’t replicate or stimulate inflammatory mediators that call in immune cells, and (c) don’t persist, the most critical issue for compromising tissue integrity and getting the immune response interested. Our laboratory addressed these issues by orienting the specific antigen in a lipid bilayer as it would appear naturally, and by providing an adjacent adjuvant in that same bilayer to stimulate immune reactivity to the entire complex of antigens. We describe in this paper a platform vaccine technology that combines a liposome for insertion of different antigen classes by different means with lipid A to enhance antigen immunogenicity. These vaccine formulations specifically induce both humoral (antibody) and cellular (cytotoxic cell) immunity and selectively stimulate immunologic memory in those cases where an antigen-specific challenge response is desired.