Production and Characterization of Synthetic ErbB2 Virosomes for Vaccination Against Breast Cancer

Abstract

Virosomes, lipid-based nanoparticles incorporating influenza surface proteins hemagglutinin (HA) and neuraminidase (NA), are an attractive biomimetic delivery system to stimulate the MHC I adaptive immune system. In contrast to conventional virosome preparations which are derived from live virus, here we describe the manufacture and characterization of synthetic virosomes incorporating recombinant HA and NA. A synthetic virosome production scheme represents a significant advance in the safety profile of this antigen delivery technology. To extend this approach to the production of a potent vaccine against breast cancer, the antigen ErbB2, the chemokine GM-CSF, and two lipid-based adjuvants (OxPAPC and MPLA) were incorporated into the virosome nanoparticles. As to the best of our knowledge, this is the first report of this approach, three different lipid formulations were evaluated to determine the incorporation efficacy of each component. The three lipid formulations evaluated were cholesterol combined with either anionic (DOPG), neutral (DOPC), or cationic (DOTAP) unsaturated-lipids. Analysis of intact virosomes revealed the presence of HA, NA, and OxPAPC on the exterior of the lipid nanoparticles. Further analysis, using disrupted virosomes, revealed that all six components were incorporated into DOPC and DOPG virosomes, with the greatest content found in DOPG virosomes for most constituents. These DOPC and DOPG virosomes were found to exhibit acceptable stability through 28 days of study as evaluated by dynamic light scattering, DOTAP virosomes displayed a continual increase in size through 28 days of study. The successful incorporation of all six components and acceptable stability of DOPC and DOPG virosomes represents a significant advance in virosomal safety and nanoparticle complexity.