Atomic Structure of Chimeric Hepatitis E Virus Designed for Targeted Nano‐Carrier and Delivery System

Abstract

The development of either oral vaccines against pathogens or biological container to carry materials for local targeting in digestive mucosa relies on the chief principle in tolerance of vehicle to harsh environment of digestive system to efficiently carry and deliver the cargo to its destination. Delivery system such as enteric‐transmitted virus‐like particles (VLPs) is advantageous because of the inherited acid‐ and proteolysis‐resistance of the parental viral capsids. In the present study, we engineered hepatitis E (HEV) VLP by inserting an antigenic V3 loop of human immunodeficiency virus (HIV) derived peptide, p18, into the recombinant HEV capsid protein (p18‐VLP) after residue tyrosine 485 on the protruding domain (P domain). Using cryo‐transmission electron microscopy (cryo‐TEM) and three dimensional (3D) image reconstruction, quaternary protein structure of the chimeric p18‐VLP reassembled to that of wild type HEV‐VLP with a slight difference at the protruding spike. This engineered particle also reacted to a specific HIV monoclonal antibody, but not HEV antibody at P‐domain suggesting that the inserted p18 was exposed on the surface of VLPs. Even though p18‐VLP was vulnerable to enzymatic cleavage, presumably occurred at the C‐terminal end of the inserted p18 peptide, the p18‐VLP remained structurally intact and maintained particle integrity. The results thus indicate the further application of this HEV‐VLP system as a candidate of oral delivery vector.This research is supported by Commission on Higher Education of ThailandGrant Funding Source: Commission on Higher Education of Thailand