Lipid-Based Delivery Systems in Development of Genetic and Subunit Vaccines

Lipidic carriers are composed of natural, synthetic, or physiological lipid/phospholipid materials. The flexibility of lipid-based delivery systems for transferring a variety of molecules such as immunomodulators, antigens, and drugs play a key role in design of effective vaccination and therapeutic strategies against infectious and non-infectious diseases. Genetic and subunit vaccines are two major groups of promising vaccines that have the potential for improving the protective potency against different diseases. These vaccine strategies rely greatly on delivery systems with various functions, including cargo protection, targeted delivery, high bioavailability, controlled release of antigens, selective induction of antigen-specific humoral or cellular immune responses, and low side effects. Lipidic carriers play a key role in local tissue distribution, retention, trafficking, uptake and processing by antigen-presenting cells. Moreover, lipid nanoparticles have successfully achieved to the clinic for the delivery of mRNA. Their broad potential was shown by the recent approval of COVID-19 mRNA vaccines. However, size, charge, architecture, and composition need to be characterized to develop a standard lipidic carrier. Regarding the major roles of lipid-based delivery systems in increasing the efficiency and safety of vaccine strategies against different diseases, this review concentrates on their recent advancements in preclinical and clinical trials.