Glycolipid-based nanosystems for the delivery of drugs, genes and vaccine adjuvant applications - Carbohydrate Chemistry: Chemical and Biological Approaches - page 372

The selected antigen can be encapsulated or associated with archaeo-
somes either during the aggregation step or after the formulation of
archaeosomes. The archaeal lipid formulations show high stability to
oxidative stress, a wide range of pH, high temperatures, action of phos-
pholipases, bile salts and serum media. 43 As a result of these properties,
archaeosomes can be prepared at any temperature in the physiological
range and stored in the presence of air/oxygen without any degradation.
Moreover, the in vitro and in vivo studies indicated that archaeosomes do
not elicit any toxicity in mice. 93
Archaeosomes naturally target cells of the mononuclear phagocytic sys-
tem making them ideally suited for delivery of antigens, as carrier systems
and as adjuvants that stimulate the immune system. A number of recent
scientific papers and patents give evidence of the current development of
formulations of archaeosomes with various antigens as new vaccines.
Uptake of archaeosomes by phagocitic cells is several times greater
than that of conventional liposomes, eliciting thereby the immune re-
sponse. For example, in murine models, administration of archaeosomes
containing encapsulated antigen caused antibody responses comparable
to those obtained by the effective but highly toxic Freund's adjuvant. 94
Mucosal infections and associated diseases remain a major societal
burden. Patel et al. 95,96 demonstrated recently that archaeosomes repre-
sent safe and effective adjuvants and delivery systems for mucosal vac-
cines and intranasal immunization. 97 The eciency of archaeosome
adjuvants for the oral route has also been validated 98,99 as well as the
development of ultradeformable archaeosomes as vehicles utilized in
transdermal delivery systems with improved skin penetration. 100
The incidence of food-borne infections from Listeria monocytogenes has
increased dramatically in the past years; the lack of an effective vaccine
against this intracellular pathogen has encouraged the use of archaeo-
somes entrapped Sags formulation. The vaccine not only enhances
cytotoxic T cell response but also helps in the clearance of pathogens,
thereby increasing the survival of immunized animals. 101
The final aspect of the current research deals with the development of
therapeutic cancer vaccines. Of particular interest is the study proposed
by Sprott et al. 102 who pointed out that synthetic archaetidylserine played
a role to enhance the CD8 þ T cell response in mice, and that vaccines
give the best protection against solid tumor growth corresponding to the
archaeosome adjuvant composition that gave the highest immune

activity in immunized mice.
Encouragingly, some of these studies have progressed to advanced
preclinical and clinical studies.

5 Conclusion
Glycolipid-containing nanosystems are highly valuable vehicles to deliver
specifically drugs, genes or antigens to targeted cells and tissues. The
presence of mono- or multivalent carbohydrate moieties exposed at the
nanocarrier

surface can display specific carbohydrate-protein