1. Functional and immunogenic characterization of diverse HCV glycoprotein E2 variants
- Author
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John Lok Man Law, Thomas Pietschmann, Joseph Marcotrigiano, Dorothea Bankwitz, Kai Schulze, Darren Hockman, Eike Steinmann, Richard J. C. Brown, Thomas Krey, Leona Dold, Alexander W. Tarr, Florian Klein, Michael P. Manns, Patrick Behrendt, Luisa J Ströh, Abdul Ghafoor Khan, Abel Viejo-Borbolla, Jason Wong, Mandy Doepke, Michael Houghton, Ulrich Spengler, Víctor González-Motos, Carlos A. Guzmán, Tanvi Khera, Daniel Todt, Michael Logan, Institut de Recherche sur les Maladies Virales et Hépatiques (IVH), Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM), TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany, and HZI, Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7 38124 Braunschweig, Germany.
- Subjects
0301 basic medicine ,Glycosylation ,Immunogen ,viruses ,Hepacivirus ,Epitope ,Epitopes ,Mice ,chemistry.chemical_compound ,0302 clinical medicine ,Viral Envelope Proteins ,chemistry.chemical_classification ,Recombinant proteins ,Mice, Inbred BALB C ,biology ,Vaccination ,Hepatitis C ,HCV ,Hcv ,Receptors, Virus ,030211 gastroenterology & hepatology ,Antibody ,chemical and pharmacologic phenomena ,Cross Reactions ,Antibodies ,Tetraspanin 28 ,Viral Proteins ,03 medical and health sciences ,Antigen ,Cell Line, Tumor ,Animals ,Humans ,Binding site ,Glycoproteins ,Binding Sites ,Hepatology ,Viral Vaccines ,biochemical phenomena, metabolism, and nutrition ,Hepatitis C Antibodies ,Virology ,Hypervariable region ,HEK293 Cells ,030104 developmental biology ,chemistry ,biology.protein ,Glycoprotein ,Broadly Neutralizing Antibodies ,Gene Deletion ,[SDV.MHEP]Life Sciences [q-bio]/Human health and pathology - Abstract
Background & Aims Induction of cross-reactive antibodies targeting conserved epitopes of the envelope proteins E1E2 is a key requirement for an hepatitis C virus vaccine. Conserved epitopes like the viral CD81-binding site are targeted by rare broadly neutralizing antibodies. However, these viral segments are occluded by variable regions and glycans. We aimed to identify antigens exposing conserved epitopes and to characterize their immunogenicity. Methods We created hepatitis C virus variants with mutated glycosylation sites and/or hypervariable region 1 (HVR1). Exposure of the CD81 binding site and conserved epitopes was quantified by soluble CD81 and antibody interaction and neutralization assays. E2 or E1-E2 heterodimers with mutations causing epitope exposure were used to immunize mice. Vaccine-induced antibodies were examined and compared with patient-derived antibodies. Results Mutant viruses bound soluble CD81 and antibodies targeting the CD81 binding site with enhanced efficacy. Mice immunized with E2 or E1E2 heterodimers incorporating these modifications mounted strong, cross-binding, and non-interfering antibodies. E2-induced antibodies neutralized the autologous virus but they were not cross-neutralizing. Conclusions Viruses lacking the HVR1 and selected glycosylation sites expose the CD81 binding site and cross-neutralization antibody epitopes. Recombinant E2 proteins carrying these modifications induce strong cross-binding but not cross-neutralizing antibodies. Lay summary Conserved viral epitopes can be made considerably more accessible for binding of potently neutralizing antibodies by deletion of hypervariable region 1 and selected glycosylation sites. Recombinant E2 proteins carrying these mutations are unable to elicit cross-neutralizing antibodies suggesting that exposure of conserved epitopes is not sufficient to focus antibody responses on production of cross-neutralizing antibodies.
- Published
- 2019