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Zhang C, Ötjengerdes RM, Roewe J, Mejias R, Marschall ALJ. Applying Antibodies Inside Cells: Principles and Recent Advances in Neurobiology, Virology and Oncology. BioDrugs 2020; 34:435-462. [PMID: 32301049 PMCID: PMC7391400 DOI: 10.1007/s40259-020-00419-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
To interfere with cell function, many scientists rely on methods that target DNA or RNA due to the ease with which they can be applied. Proteins are usually the final executors of function but are targeted only indirectly by these methods. Recent advances in targeted degradation of proteins based on proteolysis-targeting chimaeras (PROTACs), ubiquibodies, deGradFP (degrade Green Fluorescent Protein) and other approaches have demonstrated the potential of interfering directly at the protein level for research and therapy. Proteins can be targeted directly and very specifically by antibodies, but using antibodies inside cells has so far been considered to be challenging. However, it is possible to deliver antibodies or other proteins into the cytosol using standard laboratory equipment. Physical methods such as electroporation have been demonstrated to be efficient and validated thoroughly over time. The expression of intracellular antibodies (intrabodies) inside cells is another way to interfere with intracellular targets at the protein level. Methodological strategies to target the inside of cells with antibodies, including delivered antibodies and expressed antibodies, as well as applications in the research areas of neurobiology, viral infections and oncology, are reviewed here. Antibodies have already been used to interfere with a wide range of intracellular targets. Disease-related targets included proteins associated with neurodegenerative diseases such as Parkinson's disease (α-synuclein), Alzheimer's disease (amyloid-β) or Huntington's disease (mutant huntingtin [mHtt]). The applications of intrabodies in the context of viral infections include targeting proteins associated with HIV (e.g. HIV1-TAT, Rev, Vif, gp41, gp120, gp160) and different oncoviruses such as human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis C virus (HCV) and Epstein-Barr virus, and they have been used to interfere with various targets related to different processes in cancer, including oncogenic pathways, proliferation, cell cycle, apoptosis, metastasis, angiogenesis or neo-antigens (e.g. p53, human epidermal growth factor receptor-2 [HER2], signal transducer and activator of transcription 3 [STAT3], RAS-related RHO-GTPase B (RHOB), cortactin, vascular endothelial growth factor receptor 2 [VEGFR2], Ras, Bcr-Abl). Interfering at the protein level allows questions to be addressed that may remain unanswered using alternative methods. This review addresses why direct targeting of proteins allows unique insights, what is currently feasible in vitro, and how this relates to potential therapeutic applications.
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Affiliation(s)
- Congcong Zhang
- Georg-Speyer-Haus, Institute for Tumor Biology and Experimental Therapy, Frankfurt am Main, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt/Mainz, Frankfurt am Main, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Rina M Ötjengerdes
- Hannover Medical School (MHH), Carl-Neuberg-Straße 1, 30625, Hannover, Germany
| | - Julian Roewe
- German Cancer Consortium (DKTK) Clinical Cooperation Unit (CCU) Neuroimmunology and Brain TumorImmunology (D170), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Rebeca Mejias
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Andrea L J Marschall
- Technische Universität Braunschweig, Institute of Biochemistry, Biotechnology and Bioinformatics, Brunswick, Germany.
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Flego M, Frau A, Accardi L, Mallano A, Ascione A, Gellini M, Fanunza E, Vella S, Di Bonito P, Tramontano E. Intracellular human antibody fragments recognizing the VP35 protein of Zaire Ebola filovirus inhibit the protein activity. BMC Biotechnol 2019; 19:64. [PMID: 31488108 PMCID: PMC6727353 DOI: 10.1186/s12896-019-0554-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 08/09/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Ebola hemorrhagic fever is caused by the Ebola filovirus (EBOV), which is one of the most aggressive infectious agents known worldwide. The EBOV pathogenesis starts with uncontrolled viral replication and subversion of both the innate and adaptive host immune response. The multifunctional viral VP35 protein is involved in this process by exerting an antagonistic action against the early antiviral alpha/beta interferon (IFN-α/β) response, and represents a suitable target for the development of strategies to control EBOV infection. Phage display technology permits to select antibodies as single chain Fragment variable (scFv) from an artificial immune system, due to their ability to specifically recognize the antigen of interest. ScFv is ideal for genetic manipulation and to obtain antibody constructs useful for targeting either antigens expressed on cell surface or intracellular antigens if the scFv is expressed as intracellular antibody (intrabody) or delivered into the cells. RESULTS Monoclonal antibodies (mAb) in scFv format specific for the EBOV VP35 were isolated from the ETH-2 library of human recombinant antibodies by phage display technology. Five different clones were identified by sequencing, produced in E.coli and expressed in CHO mammalian cells to be characterized in vitro. All the selected scFvs were able to react with recombinant VP35 protein in ELISA, one of the scFvs being also able to react in Western Blot assay (WB). In addition, all scFvs were expressed in cell cytoplasm as intrabodies; a luciferase reporter gene inhibition assay performed in A549 cells showed that two of the scFvs can significantly hamper the inhibition of the IFN-β-induced RIG-I signaling cascade mediated by EBOV VP35. CONCLUSION Five antibodies in scFv format recognize an active form of EBOV VP35 in ELISA, while one antibody also recognizes VP35 in WB. Two of these scFvs were also able to interfere with the intracellular activity of VP35 in a cell system in vitro. These findings suggest that such antibodies in scFv format might be employed to develop therapeutic molecules able to hamper EBOV infections.
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Affiliation(s)
- Michela Flego
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy.
| | - Aldo Frau
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato SS554 09042 Monserrato, Cagliari, Italy
| | - Luisa Accardi
- Department of Infectious Diseases, Viral Hepatitis, Oncoviruses and Retroviruses (EVOR) unit, Istituto Superiore di Sanità (ISS), Viale Regina Elena 299, 00161, Rome, Italy
| | - Alessandra Mallano
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy
| | - Alessandro Ascione
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy
| | - Mara Gellini
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy
| | - Elisa Fanunza
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato SS554 09042 Monserrato, Cagliari, Italy
| | - Stefano Vella
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy
| | - Paola Di Bonito
- Department of Infectious Diseases, Viral Hepatitis, Oncoviruses and Retroviruses (EVOR) unit, Istituto Superiore di Sanità (ISS), Viale Regina Elena 299, 00161, Rome, Italy.
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato SS554 09042 Monserrato, Cagliari, Italy.
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Recent Advances with ER Targeted Intrabodies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 917:77-93. [DOI: 10.1007/978-3-319-32805-8_5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Marschall ALJ, Dübel S, Böldicke T. Specific in vivo knockdown of protein function by intrabodies. MAbs 2015; 7:1010-35. [PMID: 26252565 PMCID: PMC4966517 DOI: 10.1080/19420862.2015.1076601] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 07/19/2015] [Accepted: 07/20/2015] [Indexed: 01/02/2023] Open
Abstract
Intracellular antibodies (intrabodies) are recombinant antibody fragments that bind to target proteins expressed inside of the same living cell producing the antibodies. The molecules are commonly used to study the function of the target proteins (i.e., their antigens). The intrabody technology is an attractive alternative to the generation of gene-targeted knockout animals, and complements knockdown techniques such as RNAi, miRNA and small molecule inhibitors, by-passing various limitations and disadvantages of these methods. The advantages of intrabodies include very high specificity for the target, the possibility to knock down several protein isoforms by one intrabody and targeting of specific splice variants or even post-translational modifications. Different types of intrabodies must be designed to target proteins at different locations, typically either in the cytoplasm, in the nucleus or in the endoplasmic reticulum (ER). Most straightforward is the use of intrabodies retained in the ER (ER intrabodies) to knock down the function of proteins passing the ER, which disturbs the function of members of the membrane or plasma proteomes. More effort is needed to functionally knock down cytoplasmic or nuclear proteins because in this case antibodies need to provide an inhibitory effect and must be able to fold in the reducing milieu of the cytoplasm. In this review, we present a broad overview of intrabody technology, as well as applications both of ER and cytoplasmic intrabodies, which have yielded valuable insights in the biology of many targets relevant for drug development, including α-synuclein, TAU, BCR-ABL, ErbB-2, EGFR, HIV gp120, CCR5, IL-2, IL-6, β-amyloid protein and p75NTR. Strategies for the generation of intrabodies and various designs of their applications are also reviewed.
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Affiliation(s)
- Andrea LJ Marschall
- Technische Universität Braunschweig, Institute of Biochemistry, Biotechnology and Bioinformatics; Braunschweig, Germany
| | - Stefan Dübel
- Technische Universität Braunschweig, Institute of Biochemistry, Biotechnology and Bioinformatics; Braunschweig, Germany
| | - Thomas Böldicke
- Helmholtz Centre for Infection Research, Recombinant Protein Expression/Intrabody Unit, Helmholtz Centre for Infection Research; Braunschweig, Germany
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Gal-Tanamy M, Zemel R, Bachmatov L, Jangra RK, Shapira A, Villanueva R, Yi M, Lemon SM, Benhar I, Tur-Kaspa R. Inhibition of protease-inhibitor-resistant hepatitis C virus replicons and infectious virus by intracellular intrabodies. Antiviral Res 2010; 88:95-106. [PMID: 20705106 PMCID: PMC4418563 DOI: 10.1016/j.antiviral.2010.08.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 06/16/2010] [Accepted: 08/04/2010] [Indexed: 12/15/2022]
Abstract
Hepatitis C virus (HCV) infection is a common cause of chronic liver disease and a serious threat to human health. The HCV NS3/4A serine protease is necessary for viral replication and innate immune evasion, and represents a well-validated target for specific antiviral therapy. We previously reported the isolation of single-chain antibodies (scFvs) that inhibit NS3/4A protease activity in vitro. Expressed intracellularly (intrabodies), these scFvs blocked NS3-mediated proliferation of NS3-transfected cells. Here we show that anti-NS3 scFvs suppress HCV RNA replication when expressed intracellularly in Huh7 hepatoma cells bearing either subgenomic or genome-length HCV RNA replicons. The expression of intrabodies directed against NS3 inhibited the autonomous amplification of HCV replicons resistant to small-molecule inhibitors of the NS3/4A protease, and replicons derived from different HCV genotypes. The combination of intrabodies and interferon-α had an additive inhibitory effect on RNA replication in the replicon model. Intrabody expression also inhibited production of infectious HCV in a cell culture system. The NS3 protease activity was inhibited by the intrabodies in NS3-expressing cells. In contrast, cell-free synthesis of HCV RNA by preformed replicase complexes was not inhibited by intrabodies, suggesting that the major mode of inhibition of viral replication is inhibition of NS3/4A protease activity and subsequent suppression of viral polyprotein processing.
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Affiliation(s)
- Meital Gal-Tanamy
- Molecular Hepatology Research Laboratory, Felsenstein Medical Research Center, Sackler School of Medicine, Tel-Aviv University, Petah Tikva, Israel
- Department of Molecular Microbiology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat Aviv Israel
- Center for Hepatitis Research, Institute for Human Infections and Immunity, and the Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Romy Zemel
- Molecular Hepatology Research Laboratory, Felsenstein Medical Research Center, Sackler School of Medicine, Tel-Aviv University, Petah Tikva, Israel
| | - Larissa Bachmatov
- Molecular Hepatology Research Laboratory, Felsenstein Medical Research Center, Sackler School of Medicine, Tel-Aviv University, Petah Tikva, Israel
| | - Rohit K. Jangra
- Center for Hepatitis Research, Institute for Human Infections and Immunity, and the Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Assaf Shapira
- Department of Molecular Microbiology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat Aviv Israel
| | - Rodrigo Villanueva
- Center for Hepatitis Research, Institute for Human Infections and Immunity, and the Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - MinKyung Yi
- Center for Hepatitis Research, Institute for Human Infections and Immunity, and the Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Stanley M. Lemon
- Center for Hepatitis Research, Institute for Human Infections and Immunity, and the Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Itai Benhar
- Department of Molecular Microbiology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat Aviv Israel
| | - Ran Tur-Kaspa
- Molecular Hepatology Research Laboratory, Felsenstein Medical Research Center, Sackler School of Medicine, Tel-Aviv University, Petah Tikva, Israel
- Department of Medicine D and Liver Institute, Rabin Medical Center, Beilinson Campus, Petah Tikva, Israel
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Karthe J, Tessmann K, Li J, Machida R, Daleman M, Häussinger D, Heintges T. Specific targeting of hepatitis C virus core protein by an intracellular single-chain antibody of human origin. Hepatology 2008; 48:702-12. [PMID: 18697213 PMCID: PMC3080105 DOI: 10.1002/hep.22366] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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.
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Affiliation(s)
- Juliane Karthe
- Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Kathi Tessmann
- Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Jisu Li
- The Liver Research Center, Rhode Island Hospital and Warren Alpert Medical School of Brown University, Providence, RI
| | - Raiki Machida
- The Liver Research Center, Rhode Island Hospital and Warren Alpert Medical School of Brown University, Providence, RI
| | - Maaike Daleman
- Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Dieter Häussinger
- Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Tobias Heintges
- Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
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Abstract
Combining exquisite specificity and high antigen-binding affinity, intrabodies have been used as a biotechnological tool to interrupt, modulate, or define the functions of a wide range of target antigens at the posttranslational level. An intrabody is an antibody that has been designed to be expressed intracellularly and can be directed to a specific target antigen present in various subcellular locations including the cytosol, nucleus, endoplasmic reticulum (ER), mitochondria, peroxisomes, plasma membrane and trans-Golgi network (TGN) through in frame fusion with intracellular trafficking/localization peptide sequences. Although intrabodies can be expressed in different forms, the most commonly used format is a singlechain antibody (scFv Ab) created by joining the antigen-binding variable domains of heavy and light chain with an interchain linker (ICL), most often the 15 amino acid linker (GGGGS)(3) between the variable heavy (VH) and variable light (VL) chains. Intrabodies have been used in research of cancer, HIV, autoimmune disease, neurodegenerative disease, and transplantation. Clinical application of intrabodies has mainly been hindered by the availability of robust gene delivery system(s) including target cell directed gene delivery. This review will discuss several methods of intrabody selection, different strategies of cellular targeting, and recent successful examples of intrabody applications. Taking advantage of the high specificity and affinity of an antibody for its antigen, and of the virtually unlimited diversity of antigen-binding variable domains available for molecular targeting, intrabody techniques are emerging as promising tools to generate phenotypic knockouts, to manipulate biological processes, and to obtain a more thorough understanding of functional genomics.
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Böldicke T. Blocking translocation of cell surface molecules from the ER to the cell surface by intracellular antibodies targeted to the ER. J Cell Mol Med 2007; 11:54-70. [PMID: 17367501 PMCID: PMC4401220 DOI: 10.1111/j.1582-4934.2007.00002.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Intracellular antibodies (intrabodies) constitute a potent tool to neutralize the function of target proteins inside specific cell compartments (cytosol, nucleus, mitochondria and ER). The intrabody technology is an attractive alternative to the generation of gene-targeted knockout animals and complements or replaces knockdown techniques such as antisense-RNA, RNAi and RNA aptamers. This article focuses on intrabodies targeted to the ER. Intracellular anti-bodies expressed and retained inside the ER (ER intrabodies) are shown to be highly efficient in blocking the translocation of secreted and cell surface molecules from the ER to the cell surface.The advantage of ER intrabodies over cytoplasmic intrabodies is that they are correctly folded and easier to select. A particular advantage of the intrabody technology over existing ones is the possibility of inhibiting selectively post-translational modifications of proteins.The main applications of ER intrabodies so far have been (i) inactivation of oncogenic receptors and (ii) functional inhibition of virus envelope proteins and virus-receptor molecules on the surface of host cells.In cancer research, the number of in vivo mouse models for evaluation of the therapeutic potential of intrabodies is increasing.In the future, endosomal localized receptors involved in bacterial and viral infections, intracellular oncogenic receptors and enzymes involved in glycosylation of tumour antigens might be new targets for ER intrabodies.
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Affiliation(s)
- Thomas Böldicke
- Helmholtz Centre for Infection Research, Department of Gene Regulation and Differentiation,Braunschweig, Germany.
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Dash S, Haque S, Joshi V, Prabhu R, Hazari S, Fermin C, Garry R. HCV-hepatocellular carcinoma: new findings and hope for effective treatment. Microsc Res Tech 2006; 68:130-48. [PMID: 16276514 DOI: 10.1002/jemt.20227] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We present here a comprehensive review of the current literature plus our own findings about in vivo and in vitro analysis of hepatitis C virus (HCV) infection, viral pathogenesis, mechanisms of interferon action, interferon resistance, and development of new therapeutics. Chronic HCV infection is a major risk factor for the development of human hepatocellular carcinoma. Standard therapy for chronic HCV infection is the combination of interferon alpha and ribavirin. A significant number of chronic HCV patients who cannot get rid of the virus infection by interferon therapy experience long-term inflammation of the liver and scarring of liver tissue. Patients who develop cirrhosis usually have increased risk of developing liver cancer. The molecular details of why some patients do not respond to standard interferon therapy are not known. Availability of HCV cell culture model has increased our understanding on the antiviral action of interferon alpha and mechanisms of interferon resistance. Interferons alpha, beta, and gamma each inhibit replication of HCV, and the antiviral action of interferon is targeted to the highly conserved 5'UTR used by the virus to translate protein by internal ribosome entry site mechanism. Studies from different laboratories including ours suggest that HCV replication in selected clones of cells can escape interferon action. Both viral and host factors appear to be involved in the mechanisms of interferon resistance against HCV. Since interferon therapy is not effective in all chronic hepatitis C patients, alternative therapeutic strategies are needed to treat chronic hepatitis C patients not responding to interferon therapy. We also reviewed the recent development of new alternative therapeutic strategies for chronic hepatitis C, which may be available in clinical use within the next decade. There is hope that these new agents along with interferon will prevent the occurrence of hepatocellular carcinoma due to chronic persistent hepatitis C virus infection. This review is not inclusive of all important scientific publications due to space limitation.
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Affiliation(s)
- Srikanta Dash
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana 70112, USA.
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Prabhu R, Khalap N, Burioni R, Clementi M, Garry RF, Dash S. Inhibition of hepatitis C virus nonstructural protein, helicase activity, and viral replication by a recombinant human antibody clone. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 165:1163-73. [PMID: 15466383 PMCID: PMC1618619 DOI: 10.1016/s0002-9440(10)63377-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Hepatitis C virus (HCV) nonstructural protein 3 (NS3), with its protease, helicase, and NTPase enzymatic activities, plays a crucial role in viral replication, and therefore represents an ideal target for the development of anti-viral agents. We have developed a recombinant human antibody (Fab) that reacts with the helicase domain of HCV NS3. The affinity-purified Fab antibody completely inhibited the helicase activity of HCV NS3 at equimolar concentration. To evaluate the effect of the Fab on HCV replication, the clone encoding the Fab gene was put into an expression vector, which converts Fab into a complete IgG1 antibody. Using a DNA-based transfection model, we demonstrated that intracellular expression of this antibody resulted in significant reduction of HCV-negative strand RNA synthesis. Intracellular expression of this antibody into either a stable cell line replicating subgenomic RNA, or a transient full-length HCV replication model, reduced both HCV RNA and viral protein expression. These results support the use of recombinant antibody fragments to inhibit NS3 enzyme as a novel, feasible, and effective approach for inhibiting HCV replication.
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Affiliation(s)
- Ramesh Prabhu
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, 1430 Tulane Ave., New Orleans LA 70112, USA
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Blazek D, Celer V. The production and application of single-chain antibody fragments. Folia Microbiol (Praha) 2003; 48:687-98. [PMID: 14976730 DOI: 10.1007/bf02993480] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
This review discusses methods for the single-chain antibody fragment ($cFv) generation and scFv expression systems, and describes potential applications of scFv in the therapy of viral diseases and cancer, with emphasis on intracellularly expressed scFvs (intrabodies), application of scFvs in detection and diagnostics, and their use in proteomics.
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Affiliation(s)
- D Blazek
- Institute of Microbiology and Immunology, Faculty of Veterinary Medicine, Veterinary and Pharmaceutical University, 612 42 Brno, Czechia
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Affiliation(s)
- Yurong Yang Wheeler
- Department of Cancer Biology, Wake Forest University School of Medicine, Medical Center Boulevard, 27157, Winston-Salem, North Carolina 27157, USA.
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Sullivan DE, Mondelli MU, Curiel DT, Krasnykh V, Mikheeva G, Gaglio P, Morris CB, Dash S, Gerber MA. Construction and characterization of an intracellular single-chain human antibody to hepatitis C virus non-structural 3 protein. J Hepatol 2002; 37:660-8. [PMID: 12399234 DOI: 10.1016/s0168-8278(02)00270-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND/AIMS We developed a single-chain antibody fragment (scFv) to the non-structural 3 protein (NS3) of hepatitis C virus (HCV) and tested its ability to interfere with the HCV replication cycle in infected hepatocytes. METHODS The variable regions of the human monoclonal antibody CM3.B6 that recognizes a conformational epitope within the helicase domain of NS3 were introduced into adenoviral vectors for expression in mammalian hepatocytes. Expression and binding properties of the scFv were analyzed by immunological assays. Effects of intracellular expression of the scFv on HCV replication were assessed in primary hepatocytes isolated from explanted livers of patients with chronic HCV infection by reverse transcription-polymerase chain reaction. RESULTS Transduction of HepG2 cells by the recombinant adenoviruses resulted in stable, efficient expression of scFv in the cytoplasm that was non-toxic to the cells. The scFv specifically bound to its cognate antigen. Significantly, intracellular expression of scFv resulted in a decrease in HCV genomic RNA in HCV infected hepatocytes. CONCLUSIONS These results indicate that specific binding of a scFv to NS3 may inhibit one or more functions of this essential viral protein thus interfering with the HCV replication cycle.
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Affiliation(s)
- Deborah E Sullivan
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
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