title: Specific targeting of hepatitis C virus core protein by an intracellular single-chain antibody of human origin.
abstract: The hepatitis C virus (HCV) core protein is essential for viral genome encapsidation and plays an important role in steatosis, immune evasion, and hepatocellular carcinoma. It may thus represent a promising therapeutic target to interfere with the HCV life-cycle and related pathogenesis. In this study, we used phage display to generate single-chain variable domain antibody fragments (scFv) to the core protein from bone marrow plasma cells of patients with chronic hepatitis C. An antibody with high-affinity binding (scFv42C) was thus identified, and the binding site was mapped to the PLXG motif (residues 84-87) of the core protein conserved among different genotypes. Whereas scFv42C displayed diffuse cytoplasmic fluorescence when expressed alone in the Huh7 human hepatoma cell line, cotransfection with the core gene shifted its subcellular distribution into that of core protein. The intracellular association of scFv42C with its target core protein was independently demonstrated by the fluorescence resonance energy transfer technique. Interestingly, expression of the single-chain antibody reduced core protein levels intracellularly, particularly in the context of full HCV replication. Moreover, cell proliferation as induced by the core protein could be reversed by scFv4C coexpression. Therefore, scFv42C may represent a novel anti-HCV agent, which acts by sequestering core protein and attenuating core protein-mediated pathogenesis.
authors.affiliation: Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Karthe
authors.forename: Kathi
authors.initials: K
authors.lastname: Tessmann
authors.forename: Jisu
authors.initials: J
authors.lastname: Li
authors.forename: Raiki
authors.initials: R
authors.lastname: Machida
authors.forename: Maaike
authors.initials: M
authors.lastname: Daleman
authors.forename: Dieter
authors.initials: D
authors.lastname: Häussinger
authors.forename: Tobias
authors.initials: T
authors.lastname: Heintges
mesh_terms: D000595:Amino Acid Sequence; D000914:Antibodies, Viral / Q000276:immunology* / Q000494:pharmacology*; D000998:Antiviral Agents / Q000276:immunology / Q000494:pharmacology; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology / Q000821:virology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D031541:Fluorescence Resonance Energy Transfer; D016174:Hepacivirus; D019698:Hepatitis C, Chronic / Q000276:immunology; D006801:Humans; D007128:Immunoglobulin Fragments / Q000276:immunology* / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism / Q000473:pathology / Q000821:virology; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology / Q000821:virology; D008969:Molecular Sequence Data; D054730:Protein Interaction Domains and Motifs / Q000276:immunology; D014758:Viral Core Proteins / Q000276:immunology*; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000914:Antibodies, Viral; D000998:Antiviral Agents; D007128:Immunoglobulin Fragments; D014758:Viral Core Proteins