Analysis of Antigenicity and Topology of E2 Glycoprotein Present on Recombinant Hepatitis C Virus-Like Particles

作者：R. Clayton, Ania M. Owsianka, Jim Aitken, Susan Marie Graham, David Bhella, Arvind H. Patel · 发表于：Journal of Virology · 年份：2002 · DOI：10.1128/jvi.76.15.7672-7682.2002 · 被引用次数：140 · 研究领域：Hepatitis C virus research、Monoclonal and Polyclonal Antibodies Research、Galectins and Cancer Biology

ABSTRACT Purification of hepatitis C virus (HCV) from sera of infected patients has proven elusive, hampering efforts to perform structure-function analysis of the viral components. Recombinant forms of the viral glycoproteins have been used instead for functional studies, but uncertainty exists as to whether they closely mimic the virion proteins. Here, we used HCV virus-like particles (VLPs) generated in insect cells infected with a recombinant baculovirus expressing viral structural proteins. Electron microscopic analysis revealed a population of pleomorphic VLPs that were at least partially enveloped with bilayer membranes and had viral glycoprotein spikes protruding from the surface. Immunogold labeling using specific monoclonal antibodies (MAbs) demonstrated these protrusions to be the E1 and E2 glycoproteins. A panel of anti-E2 MAbs was used to probe the surface topology of E2 on the VLPs and to compare the antigenicity of the VLPs with that of truncated E2 (E2 660 ) or the full-length (FL) E1E2 complex expressed in mammalian cells. While most MAbs bound to all forms of antigen, a number of others showed striking differences in their abilities to recognize the various E2 forms. All MAbs directed against hypervariable region 1 (HVR-1) recognized both native and denatured E2 660 with comparable affinities, but most bound either weakly or not at all to the FL E1E2 complex or to VLPs. HVR-1 on VLPs was accessible to these MAbs only after denaturation. Importantly, a subset...