Nanoparticle Vaccines Adopting Virus-like Features for Enhanced Immune Potentiation

Chattopadhyay, Saborni; Chen, Jui-Yi; Chen, Hui-Wen; Hu, Che-Ming Jack

The structural fluidity of liposomes offers flexibility in platform modification towards virus mimicry. For example, the development of virosomes, which are fusion vesicles prepared from viral particles and synthetic liposomes, is an adaption that highlights the fundamental similarity between liposomes and viruses. Derived from the membrane vesicles of viruses, virosomes consist of liposome-like lipid vesicles and viral envelope glycoproteins. The fusion vesicles retain some viral characteristics (i.e. epitope presentation) and have been applied for both drug delivery and vaccination purposes [37, 38] . The applicability of this platform as a vaccine candidate has been demonstrated extensively using influenza virus-derived virosomes [39] [40] [41] [42] . In studies that apply virosomes for anti-influenza vaccination, derivatized influenza virosomes were shown to be non-infective as their genetic materials were removed. Upon in vivo administration, these virosomes were rapidly uptaken by antigen presenting cells and in turn activated numerous other immune cells [43] [44] [45] [46] . Immunization with virosomes was reported to reactivate influenza-specific memory CD4+ T cells that subsequently supported the proliferation of antigen-specific effector cells [46] , leading to enhanced anti-influenza immune responses [47] . Besides influenza-based virosomes, induction of cytotoxic T lymphocyte responses has been demonstrated with a Sendai virus-based carrier system loaded with ovalbumin (OVA). It was demonstrated that Sendai virosomes fused with OVA elicited stronger CTL responses against the model antigen [48] .