| Abstract | Archaeosomes, liposomes made from the polar lipids extracted from the membranes of Archaea, have been extensively studied for potential applications in drug and vaccine delivery over the past decade only. Archaeosomes offer significant advantages as nanodelivery vesicles over conventional liposomes made from the ester lipids found in Eukarya and Bacteria. The regularly branched, usually fully saturated isopranoid chains of archaeal polar lipids are attached to the sn-2, 3 carbons of the glycerol backbone(s) via ether bonds. In addition to monopolar lipids, as commonly found in eukaryotic and bacterial polar lipids, membrane-spanning bipolar lipids are encountered in archaeal species. These distinct features of archaeal polar lipids confer relatively superior physico-chemical stability properties to archaeosomes, such as thermal stability, stability in serum, stability at extremes of pH range, resistance to oxidative stress, and against the action of phospholipases and bile salts. Extensive in vitro and in vivo murine model studies indicate that archaeosomes are safe. These properties are beneficial for nanodelivery vesicle applications in biotechnology. Additionally, archaeosomes have been shown to be highly efficacious as self- adjuvanting vaccine delivery vesicles that promote robust, antigen- specific, humoral and cell-mediated immune responses, including CD8 + CTL responses, to encapsulated protein antigens. These immune responses are well sustained over time, and are subject to strong memory responses. In murine models, archaeosome-delivered vaccines have demonstrated strong, long-lasting protective immunity against intracellular pathogens, as well as prophylactic and therapeutic efficacies against the development of experimental cancers. The archaeosome nanodelivery system is now ready for progressing from the laboratory to evaluations for actual commercial applications. |
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