Tumor-associated Wortmannin antigens include viral proteins (e.g. HPV), chromosomal translocation products (e.g. bcr/abl), overexpressed proteins likeHER2/neu, telomerase, MUC1 and others [Kozako et al. 2012]. In Table 3 some recent examples of experimental liposome-based cancer vaccines are listed. Table 3. Examples of liposomal therapeutic cancer vaccines. Archaeosomes Archaebacteria (Archaea) were discovered and classified by Woese and Fox as a new group of prokaryotes, besides the Eubacteria (Bacteria)

[Woese and Fox, 1977]. Archaea contain DNA-dependent RNA polymerases and proteinaceous cell walls that lack peptidoglycan. Their cell membranes are composed of L-glycerol ether lipids with isoprenoid chains instead of D-glycerol ester lipids with fatty acid chains [Spang et al. 2013]. Archaeal lipids are uniquely constituted of ether-linked isoprenoid phytanyl archaeol (diether) or caldarchaeol (tetraether) cores conferring high

membrane stability. Archaeosomes are liposomes prepared with archaeal glycerolipids. The head groups displayed on the glycerol lipid cores of archaeosomes interact with APCs and induce TH1, TH2 and CD8+ T-cell responses to the entrapped antigen. The immune responses are persistent and subject to strong memory responses [Krishnan and Sprott, 2008; Benvegnu et al. 2009]. The polar lipid from the archaeon, Methanobrevibacter smithii, has been well characterized for its adjuvant potential. It contains archaetidyl serine, promoting interaction with a PS receptor on APCs. These archaeosomes mediate MHC-I cross priming and promote costimulation by APCs without inflammatory cytokine production [Krishnan et al. 2000]. Patel and colleagues showed that archaesomes prepared from M. smithii lipids were suitable

adjuvants for multivalent mucosal vaccines. Archaeosomes containing the encapsulated antigens OVA, bovine serum albumin and hen egg lysozyme conferred strong and sustained specific antibody responses to all three antigens [Patel et al. 2004]. Intranasal immunization of mice with the archaeal lipid mucosal vaccine adjuvant and delivery (AMVAD) system, obtained by interaction of archaeosomes/antigens with multivalent cations, induced robust mucosal antigen-specific IgA responses. AMVAD formulations are stable, safe and show protective efficacy in murine models of infection/challenge [Patel and Chen, 2010]. Archaeosomes prepared from lipids of Entinostat the nonpathogenic bacteria Leptospira biflexa (leptosomes) and Mycobacterium smegmatis (smegmosomes) were used as adjuvants. Both vesicles caused strong APC activation, cytokine release and expression of costimulatory signals, which was significantly higher for smegmosomes compared with leptosomes. APC activation by both formulations induced immune responses in mice to entrapped OVA [Faisal et al. 2009, 2011].