HEV's natural infection occurs though the feco-oral routes. Thus, evolutionarily, the HEV particle is stable in the stomach and the intestines and can penetrate the mucosal layer to reach the blood stream and its destination. Thus, the non-infectious synthetic HEVNP can be packed with drugs & cancer targeting molecules and be orally administered; pain-free, and accurate. This novel technology of harvesting HEVNP, purifying it, and packing it with drugs is a huge step towards revolutionizing precision medicine.
Surface Functionalization
The HEV VLP is uniquely modular, and extensive modification of the surface spikes by genetic engineering or chemical modification does not affect the formation of a stable, icosahedral scaffold. Additionally, the modifications are displayed in their correct conformations on the VLP surface. We have made recombinant HEV VLPs displaying antigenic epitopes from HIV envelope proteins, or chemically modified to express breast cancer targeting ligands on the surface. These VLPs are structurally similar to wild type VLPs, but chemically resemble the derivatizations on their surfaces. For example, oral administration of HIV epitope-chimeric VLPs induced a strong and specific immune response in mice. The breast cancer targeting VLPs successfully trafficked to tumor sites in vivo and in cells.
Modularity also enables the VLP to be disassembled and reassembled in vitro in the appropriate chemical environment. Critical positive charges on the inner surface of the VLP stabilize its re-assembly, and negatively charged molecules such as DNA can be encapsulated of DNA in the re-assembled particle. We encapsulated DNA encoding HIV proteins in the VLPs, and administered them orally in mice. Gag protein was expressed in gut epithelial sections, and a highly specific anti-Gag immune response was generated as well. By fine-tuning various parameters of vaccine development, such as optimizing the efficiency of DNA encapsulation and modifying the VLP surface for better targeting to specific cell types, we wish to develop a simple but effective targeting tool that has enormous clinical implications. Additional modification of the particle can enable labeling for various imaging modalities, such as electron microscopy and in situ fluorescence imaging.

The Unique Structure of HEVNP

Virus-like particles (VLPs) have been used as nanocarriers to display foreign epitopes and/or deliver small molecules in a highly specific manner for use as vaccines or therapeutic agents against disease phenotypes. This is facilitated mainly by their ability to self-assemble and the ease of genetically modifying them. Hepatitis E virus (HEV) is composed of a nonenveloped icosahedral capsid, enclosing a singlestranded RNA genome of 7.2 kilobases. The major capsid protein is encoded by the second open reading frame (ORF2) and is essential not only for virus assembly, but also for immunogenicity and host interaction. The recombinant capsid protein (CP, AKA HEVNP) is able to self-assemble into virus-like particles when expressed in insect cells after deletion of 111 amino acids from the N-terminal end and 52 amino acids from the C-terminal end. CP folds into three domains: S (shell; amino acids 118-317), M (middle; amino acids 318-451) and P (protruding; amino acids 452-606.
The noninfectious hepatitis E nanoparticles self assembled into T=1 nanocapsids. These nanocapsids can be disassembled and reassembled, packing drugs in the process.