title: Combination of neutralizing monoclonal antibodies against Hepatitis C virus E2 protein effectively blocks virus infection.
abstract: Hepatitis C virus (HCV) represents a major global health threat. The envelope glycoproteins, E1-E2 of HCV play an important role in infection by binding to hepatocyte surface receptors leading to viral entry. Several regions on the E1-E2 are conserved for maintaining structural stability, despite the high mutation rate of HCV. Identification of antigenic determinants in these domains would aid in the development of anti-virals. The present study was aimed to delineate neutralizing epitopes by generating monoclonal antibodies (mAbs) to envelope proteins that can block virus binding and entry. Using HCV-like particles (HCV-LPs) corresponding to genotype 3a (prevalent in India), we obtained three mAbs specific for the E2 protein that significantly inhibited virus binding to hepatoma cells. Using overlapping protein fragments and peptides of the E2 protein, the epitopes corresponding to the mAbs were delineated. MAbs H6D3 and A10F2 recognise sequential linear epitopes, whereas, mAb E3D8 recognises a discontinuous epitope. The epitope of mAb E3D8 overlaps with the CD81 receptor-binding site and that of mAb A10F2 with the hypervariable region 2 of the E2 protein. The epitopes corresponding to these mAbs are distinct and unique. A combination of these antibodies significantly inhibited HCV binding and entry in both HCV pseudoparticle (in vitro) and HCV cell culture (ex vivo) system compared to the mAbs alone (P<0.0001). In conclusion, our findings support the potential of employing a cocktail of neutralizing mAbs in the management of HCV infection.
authors: Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India.
authors: Mihika
authors: M
authors: Bose
authors: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India.
authors: Ranajoy
authors: R
authors: Mullick
authors: Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India.
authors: Soma
authors: S
authors: Das
authors: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India.
authors: Saumitra
authors: S
authors: Das
authors: Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India. Electronic address: anjali@biochem.iisc.ernet.in.
authors: Anjali A
authors: AA
authors: Karande
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D057134:Antibodies, Neutralizing / Q000276:immunology*; D016466:CHO Cells; D045744:Cell Line, Tumor; D003412:Cricetulus; D005838:Genotype; D016174:Hepacivirus / Q000276:immunology / Q000502:physiology*; D006526:Hepatitis C / Q000276:immunology* / Q000821:virology; D006801:Humans; D016056:Immunodominant Epitopes / Q000276:immunology; D007194:India; D051379:Mice; D011485:Protein Binding; D060225:Tetraspanin 28 / Q000235:genetics / Q000276:immunology; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology*; D014771:Virion / Q000276:immunology / Q000502:physiology; D053585:Virus Attachment; D053586:Virus Internalization
chemical_list: D000911:Antibodies, Monoclonal; D057134:Antibodies, Neutralizing; C554798:CD81 protein, human; C087035:E1 protein, Hepatitis C virus; D016056:Immunodominant Epitopes; D060225:Tetraspanin 28; D014759:Viral Envelope Proteins; C091015:glycoprotein E2, Hepatitis C virus
keywords: Combination therapy; Hepatitis C virus; Monoclonal antibodies; Neutralizing antibodies; Virus-like particles