Generation and characterization of monoclonal antibodies against a cyclic variant of Hepatitis C Virus E2 epitope 412-422

Sandomenico, A. et al. (2016) Generation and characterization of monoclonal antibodies against a cyclic variant of Hepatitis C Virus E2 epitope 412-422. Journal of Virology, 90(7), pp. 3745-3759. (doi: 10.1128/JVI.02397-15) (PMID:26819303) (PMCID:PMC4794675)

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Abstract

Hepatitis C virus (HCV) E2 envelope glycoprotein is crucial for virus entry into hepatocytes. A conserved region of E2 encompassing amino acids 412-423 and containing Trp420, a residue critical for virus entry, is recognized by several broadly neutralizing antibodies. Peptides embodying this epitope I sequence adopt a β-hairpin conformation when bound to neutralizing monoclonal antibodies (MAbs) AP33 and HCV-1. We therefore generated new mouse MAbs that were able to bind to a cyclic peptide containing E2 residues 412-422 (C-Epitope I) but not to the linear counterpart. These MAbs bound to purified E2 with affinities of about 50 nM, but they were unable to neutralize virus infection. Structural analysis of the complex between C-Epitope I and one of our MAbs (C2) show that the Trp420 side chain is largely buried in the combining site and that the Asn417 side chain, which is glycosylated in E2 and solvent-exposed in other complexes, is slightly buried upon C2 binding. Also, the orientation of the cyclic peptide in the antibody combining site is rotated by 180° compared to other complexes. All these structural features, however, do not explain the lack of neutralization activity. This is instead ascribed to the high selectivity of the new MAbs for the cyclic epitope and to their inability to interact with the epitope in more flexible and extended conformations, which recent data suggest play a role in the mechanisms of neutralization escape.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Owsianka, Dr Anna and Patel, Professor Arvind
Authors: Sandomenico, A., Leonardi, A., Berisio, R., Sanguigno, L., Focà, G., Focà, A., Ruggiero, A., Doti, N., Muscariello, L., Barone, D., Farina, C., Owsianka, A., Vitagliano, L., Patel, A. H., and Ruvo, M.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
Journal Name:Journal of Virology
Publisher:American Society for Microbiology
ISSN:0022-538X
ISSN (Online):1098-5514
Copyright Holders:Copyright © 2016 Sandomenico et al.
First Published:First published in Journal of Virology 90(7):3745-3759
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
656491Basis of the host range and tissue tropism for hepatitis C virusArvind PatelMedical Research Council (MRC)MC_UU_12014/2MVLS III - CENTRE FOR VIRUS RESEARCH