title: Production and characterization of monoclonal antibodies specific for a conserved epitope within hepatitis C virus hypervariable region 1.
abstract: Frequent mutations in hypervariable region 1 (HVR1) of the main envelope protein of hepatitis C virus (HCV) is a major mechanism of persistence by escaping the host immune recognition. HVR1 contains an epitope eliciting neutralizing antibodies. This study was aimed to prepare broadly cross-reacting, high-affinity, monoclonal antibodies (MAb) to the HVR1 C terminus of HCV with potential therapeutic neutralizing capacity. A conserved amino residue group of glycine (G) at position 23 and glutamic acid (Q) at position 26 in HVR1 was confirmed as a key epitope against which two MAbs were selected and characterized. MAbs 2P24 and 15H4 were immunoglobulin G1 kappa chain [IgG1(kappa)], cross-reacted with 32 and 30 of 39 random C-terminal HVR1 peptides, respectively, and did not react with other HCV peptides. The V(H) of 2P24 and 15H4 heavy chains originated from Igh germ line v gene family 1 and 8, respectively. In contrast, the V(L) kappa sequences were highly homologous. The affinity (K(d)) of 2P24 and 15H4 (10(-9) or 10(-8) M with two immunizing peptides and 10(-8) M with two nonimmunizing HVR1 peptides) paralleled the reactivity obtained with peptide enzyme immunoassay. MAbs 2P24 and 15H4 captured 25 of 31 (81%) HCV in unselected patients' plasmas. These antibodies also blocked HCV binding to Molt-4 cells in a dose-dependent fashion. The data presented suggest that broadly cross-reactive MAbs to a conserved epitope within HCV HVR1 can be produced. Clinical application for passive immunization in HCV-related chronic liver disease and after liver transplantation is considered.
authors.affiliation: National Blood Service, Division of Transfusion Medicine, East Anglia Blood Centre, Cambridge CB2 2PT, United Kingdom.
authors.forename: C
authors.initials: C
authors.lastname: Li
authors.forename: D
authors.initials: D
authors.lastname: Candotti
authors.forename: J P
authors.initials: JP
authors.lastname: Allain
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000737:chemistry / Q000276:immunology*; D000915:Antibody Affinity; D000939:Epitopes; D016174:Hepacivirus / Q000276:immunology*; D006526:Hepatitis C / Q000628:therapy; D006801:Humans; D008969:Molecular Sequence Data; D014611:Vaccination; D014761:Viral Hepatitis Vaccines / Q000627:therapeutic use; D014764:Viral Proteins / Q000032:analysis / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; C400562:HVR1 protein, Hepatitis C virus; D014761:Viral Hepatitis Vaccines; D014764:Viral Proteins