Ultrastructural Characterization of Virus-Like Particles Produced by a Recombinant Baculovirus Expression Vector

Abstract

Analysis of Hepatitis C virus (HCV) assembly and packaging, and the study of virus-cell interactions, have been impeded by the lack of a robust cell culture system and a viable small animal model. Recently, an alternative approach utilizing recombinant gene technology has been implemented. We describe a system in which specific HCV genes are cloned into a baculovirus to form a recombinant baculovirus expression vector that produces HCV proteins that self-assemble into enveloped virus-like particles (VLP). Four HCV structural genes were cloned into the baculovirus expression vector under the control of the polyhedrin promoter, and were then recombined with baculovirus DNA. A baculovirus with no HCV insert served as a negative control (wild-type). Ovary cells (Spodoptera frugiperda) were infected with either the recombinant or wild type baculovirus. Five-days post-infection, a group of cells were harvested, fixed in McDowell-Trumps solution, and routinely prepared for transmission electron microscopy (TEM).