Abstract

Liposomes, as versatile lipid-based nanocarriers, have emerged as a critical platform in modern vaccinology, functioning both as potent adjuvants and sophisticated delivery systems. This review comprehensively examines the physicochemical properties of liposomes—including size, charge, and lipid composition—that govern their interaction with the immune system, particularly antigen-presenting cells (APCs). The primary objective is to elucidate the dual role of liposomes in enhancing vaccine efficacy: by protecting encapsulated antigens from degradation and facilitating their targeted delivery to APCs via phagocytosis, and by acting as an intrinsic adjuvant to promote robust innate and adaptive immune responses. Key findings highlight that optimizing liposome characteristics, such as incorporating immunostimulatory components (e.g., PAMP ligands), is crucial for modulating the strength and type of immune response. The manuscript discusses the fundamental mechanisms underlying the mobilization of immunity upon encountering liposomal vaccine complexes and reviews the clinical translation of this technology, including licensed liposomal vaccines and the recent success of mRNA-loaded lipid nanoparticles. The significance of this work lies in providing a framework for the rational design of next-generation liposome-based vaccines against infectious diseases and cancer.