Lipospheres for vaccine delivery

The tremendous advances of genetic engineering, and the ability to obtain many synthetic recombinant protein antigens derived from parasites, viruses, and bacteria, have revolutionized the development of new generation vaccines. Although the new, small, synthetic antigens offer advantages in the selection of antigenic epitopes and safety, a general drawback of small antigens is poor immunogenicity. Unfortunately, the body’s immune system does not respond strongly to small peptides. In particular, macrophages do not readily ingest and process the small antigens, resulting in low antibody titers and the need for repeated immunizations. This lack of immunogenicity has created an acute need to identify pharmaceutically acceptable delivery systems for these new antigens.