Design considerations for liposomal vaccines: Influence of formulation parameters on antibody and cell-mediated immune responses to liposome associated antigens

Abstract

Liposomes (phospholipid bilayer vesicles) are versatile and robust delivery systems for induction of antibody and T lymphocyte responses to associated subunit antigens. In the last 15 years, liposome vaccine technology has matured and now several vaccines containing liposome-based adjuvants have been approved for human use or have reached late stages of clinical evaluation. Given the intensifying interest in liposome-based vaccines, it is important to understand precisely how liposomes interact with the immune system and stimulate immunity. It has become clear that the physicochemical properties of liposomal vaccines – method of antigen attachment, lipid composition, bilayer fluidity, particle charge, and other properties – exert dramatic effects on the resulting immune response. Here, we present a comprehensive review of the physicochemical properties of liposomal vaccines and how they influence immune responses. A discussion of novel and emerging immunomodulators that are suitable for inclusion in liposomal vaccines is also presented. Through a comprehensive analysis of the body of liposomal vaccine literature, we enumerate a series of principles that can guide the rational design of liposomal vaccines to elicit immune responses of a desired magnitude and quality. We also identify major unanswered questions in the field, pointing the direction for future study.

Liposome-Based Immunotherapy Against Autoimmune Diseases: Therapeutic Effect on Multiple Sclerosis

“…Various types of liposomes are used clinically as vehicles for drugs and vaccines [5]. Liposomes can be designed for multiple purposes, including immune modulation to enhance or inhibit a specific response [6].…”

Cryogenic transmission electron microscopy of recombinant tuberculosis vaccine antigen with anionic liposomes reveals formation of flattened liposomes

“…7 Nevertheless, anionic liposomes proved to be a potent adjuvant formulation platform when combined with a TLR4 agonist and the vaccine antigen. While some reports conclude that electrostatic or covalent antigen association with liposomes enhances vaccine potency, [20][21][22] other researchers have reported that simple mixtures of anionic liposomes with anionic vaccine antigens result in potent antibody and cellular immune responses, where significant antigen-liposome association was evident even though both components were anionic.…”

Novel Heat-Stable Enterotoxin (STa) Immunogen Based on Cationic Nanoliposomes: Preparation, Characterization and Immunization

“…Figure 6 showed the pattern of immune response against STa Regarding the stability of STa cationic nanoliposomes after storage for three months, there was non-statistically significant change in either the particle size, PDI or zeta potential values, suggesting the subtle retaining of their physicochemical properties during refrigeration storage. This stability might be attributed to the charged nature of the vesicles, which allowed the vesicles to resist aggregation and fusion [44,45] Furthermore, being in the range of +30 mV, the vesicular dispersions were considered to be adequately stable by creating sufficient repulsion between the particles [46]. efficiency of 12.56% ± 4.2, strongly suggested the electrostatic and physical incorporation of STa onto cationic lipids.…”