Lipid-based antigen delivery systems

Abstract

Lipid-based carriers, including liposomes and emulsions, have been studied as antigen delivery systems to improve humoral and cellular immune responses. Lipid-based delivery systems have been tailored based on the physicochemical properties of antigens and administration routes. Non-covalent encapsulation or chemical conjugation of antigens onto the surface of nanocarriers has been reported to load high amounts of antigen, protect antigens from degradation, and enhance cellular uptake by immune cells. Moreover, active targeting to antigen-presenting cells can be achieved through surface modification of lipid-based nanostructures. Antigens, which include proteins, peptides and nucleic acids, have been delivered by appropriate lipid-based delivery systems, and antigen-loaded lipid nanoparticles have been shown to cause greater immune responses compared with naked antigens. For in vivo applications, both invasive and non-invasive routes have been adopted for vaccination with antigen-loaded lipid nanocarriers. In this review, we address recent progress, current status, and clinical applications of lipid-based antigen delivery systems.