title: Isolation and characterization of monoclonal antibodies that inhibit hepatitis C virus NS3 protease.
abstract: A series of mouse monoclonal antibodies (MAbs) to the nonstructural protein 3 (NS3) of hepatitis C virus was prepared. One of these MAbs, designated 8D4, was found to inhibit NS3 protease activity. This inhibition was competitive with respect to the substrate peptide (K(i) = 39 nM) but was significantly decreased by the addition of the NS4A peptide, a coactivator of the NS3 protease. 8D4 also showed marked inhibition of the NS3-dependent cis processing of the NS3/4A polyprotein but had virtually no effect on the succeeding NS3/4A-dependent trans processing of the NS5A/5B polyprotein in vitro. Epitope mapping of 8D4 with a random peptide library revealed a consensus sequence, DxDLV, that matched residues 79 to 83 (DQDLV) of NS3, a region containing the catalytic residue Asp-81. Furthermore, synthetic peptides including this sequence were shown to block the ability of 8D4 to bind to NS3, indicating that 8D4 interacts with the catalytic region of NS3. The data showing decreased inhibition potency of 8D4 against the NS3/4A complex suggest that 8D4 recognizes the conformational state of the protease active site caused by the association of NS4A with the protease.
authors.affiliation: Pharmaceuticals & Biotechnology Laboratory, Japan Energy Corporation, Toda-shi, Saitama, 335-8502, Japan. uenot@kaiju.medic.kumamoto-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Ueno
authors.forename: S
authors.initials: S
authors.lastname: Misawa
authors.forename: Y
authors.initials: Y
authors.lastname: Ohba
authors.forename: M
authors.initials: M
authors.lastname: Matsumoto
authors.forename: M
authors.initials: M
authors.lastname: Mizunuma
authors.forename: N
authors.initials: N
authors.lastname: Kasai
authors.forename: K
authors.initials: K
authors.lastname: Tsumoto
authors.forename: I
authors.initials: I
authors.lastname: Kumagai
authors.forename: H
authors.initials: H
authors.lastname: Hayashi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001667:Binding, Competitive; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D016174:Hepacivirus / Q000201:enzymology*; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D011487:Protein Conformation; D020349:Surface Plasmon Resonance; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D000911:Antibodies, Monoclonal; D010455:Peptides; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases