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Chance R, Kang AS. Eukaryotic ribosome display for antibody discovery: A review. Hum Antibodies 2024; 32:107-120. [PMID: 38788063 DOI: 10.3233/hab-240001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2024]
Abstract
Monoclonal antibody biologics have significantly transformed the therapeutic landscape within the biopharmaceutical industry, partly due to the utilisation of discovery technologies such as the hybridoma method and phage display. While these established platforms have streamlined the development process to date, their reliance on cell transformation for antibody identification faces limitations related to library diversification and the constraints of host cell physiology. Cell-free systems like ribosome display offer a complementary approach, enabling antibody selection in a completely in vitro setting while harnessing enriched cellular molecular machinery. This review aims to provide an overview of the fundamental principles underlying the ribosome display method and its potential for advancing antibody discovery and development.
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Huličiak M, Biedermanová L, Berdár D, Herynek Š, Kolářová L, Tomala J, Mikulecký P, Schneider B. Combined in vitro and cell-based selection display method producing specific binders against IL-9 receptor in high yields. FEBS J 2023. [PMID: 36637991 DOI: 10.1111/febs.16726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 12/03/2022] [Accepted: 01/11/2023] [Indexed: 01/14/2023]
Abstract
We combined cell-free ribosome display and cell-based yeast display selection to build specific protein binders to the extracellular domain of the human interleukin 9 receptor alpha (IL-9Rα). The target, IL-9Rα, is the receptor involved in the signalling pathway of IL-9, a pro-inflammatory cytokine medically important for its involvement in respiratory diseases. The successive use of modified protocols of ribosome and yeast displays allowed us to combine their strengths-the virtually infinite selection power of ribosome display and the production of (mostly) properly folded and soluble proteins in yeast display. The described experimental protocol is optimized to produce binders highly specific to the target, including selectivity to common proteins such as BSA, and proteins potentially competing for the binder such as receptors of other cytokines. The binders were trained from DNA libraries of two protein scaffolds called 57aBi and 57bBi developed in our laboratory. We show that the described unconventional combination of ribosome and yeast displays is effective in developing selective small protein binders to the medically relevant molecular target.
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Affiliation(s)
- Maroš Huličiak
- Institute of Biotechnology of the Czech Academy of Sciences, Vestec, Czech Republic
| | - Lada Biedermanová
- Institute of Biotechnology of the Czech Academy of Sciences, Vestec, Czech Republic
| | - Daniel Berdár
- Institute of Biotechnology of the Czech Academy of Sciences, Vestec, Czech Republic
| | - Štěpán Herynek
- Institute of Biotechnology of the Czech Academy of Sciences, Vestec, Czech Republic
| | - Lucie Kolářová
- Institute of Biotechnology of the Czech Academy of Sciences, Vestec, Czech Republic
| | - Jakub Tomala
- Institute of Biotechnology of the Czech Academy of Sciences, Vestec, Czech Republic
| | - Pavel Mikulecký
- Institute of Biotechnology of the Czech Academy of Sciences, Vestec, Czech Republic
| | - Bohdan Schneider
- Institute of Biotechnology of the Czech Academy of Sciences, Vestec, Czech Republic
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Li H, Liu L, Ning B, Sun Z, Yao S, Jiang Y, Liu J. Selection of an artificial paraquat-specific binding protein from a ribosome display library based on a lipocalin scaffold. Biotechnol Appl Biochem 2020; 68:1372-1385. [PMID: 33169873 DOI: 10.1002/bab.2059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 10/15/2020] [Indexed: 11/06/2022]
Abstract
In this study, an anticalin that could specifically bind paraquat (PQ), a quaternary nitrogen herbicide, as a new set of engineered receptor protein with antibody-like properties was generated to detect PQ concentration. To this end, a native and random library was constructed and engineered to allow in vitro transcription and translation using an Escherichia coli lysate system. Meanwhile, a PQ derivative that carries an active aliphatic carboxylate group at the end of an aliphatic spacer arm was synthesized. Then, this compound was coupled covalently to the carrier protein bovine serum albumin/ovalbumin and amino-functionalized paramagnetic beads. Alternating selection in solution and immobilization in microtiter wells were used to pan mRNA-ribosome-antibody complexes. After several rounds of ribosome display, three variants were selected from a random library of the bilin-binding protein. The variants that could bind complex PQ with high affinity and exhibit IC50 values as low as 14.039 ± 0.970 ng/mL were identified. Moreover, the limits of detection reached 0.083 ± 0.011 ng/mL. Our data suggest that the generation of anticalins may provide a promising alternative to recombinant antibody fragments to create a stable receptor protein against hapten with bioanalytical relevance.
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Affiliation(s)
- Hua Li
- Department of Endoscopy, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy of Tianjin, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
| | - Li Liu
- Inner Mongolia, Baotou Teachers College of Inner Mongolia University of Science and Technology, Baotou, People's Republic of China
| | - Baoan Ning
- Tianjin Key Laboratory of Risk Assessment and Control Technology for Environment and Food Safety, Institute of Health and Environmental Medicine, Tianjin, People's Republic of China
| | - Zhiyong Sun
- NO.946 Hospital of PLA, Yining, Xinjiang, People's Republic of China
| | - Sun Yao
- Inner Mongolia North Heavy Industry No.5 Middle School, Baotou, Inner Mongolia, People's Republic of China
| | - Yongqiang Jiang
- Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, People's Republic of China
| | - Jianqing Liu
- Inner Mongolia, Baotou Teachers College of Inner Mongolia University of Science and Technology, Baotou, People's Republic of China
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Li R, Kang G, Hu M, Huang H. Ribosome Display: A Potent Display Technology used for Selecting and Evolving Specific Binders with Desired Properties. Mol Biotechnol 2018; 61:60-71. [DOI: 10.1007/s12033-018-0133-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Salimi F, Forouzandeh Moghadam M, Rajabibazl M. Development of a novel anti-HER2 scFv by ribosome display and in silico evaluation of its 3D structure and interaction with HER2, alone and after fusion to LAMP2B. Mol Biol Rep 2018; 45:2247-2256. [DOI: 10.1007/s11033-018-4386-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 09/12/2018] [Indexed: 12/31/2022]
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Chen Q, Tao T, Bie X, Lu F, Li Y, Lu Z. Characterization of a single-chain variable fragment specific to Cronobacter spp. from hybridoma based on outer membrane protein A. J Microbiol Methods 2016; 129:136-143. [DOI: 10.1016/j.mimet.2016.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 07/23/2016] [Accepted: 08/02/2016] [Indexed: 12/30/2022]
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Abstract
Since the development of therapeutic antibodies the demand of recombinant human antibodies is steadily increasing. Traditionally, therapeutic antibodies were generated by immunization of rat or mice, the generation of hybridoma clones, cloning of the antibody genes and subsequent humanization and engineering of the lead candidates. In the last few years, techniques were developed that use transgenic animals with a human antibody gene repertoire. Here, modern recombinant DNA technologies can be combined with well established immunization and hybridoma technologies to generate already affinity maturated human antibodies. An alternative are in vitro technologies which enabled the generation of fully human antibodies from antibody gene libraries that even exceed the human antibody repertoire. Specific antibodies can be isolated from these libraries in a very short time and therefore reduce the development time of an antibody drug at a very early stage.In this review, we describe different technologies that are currently used for the in vitro and in vivo generation of human antibodies.
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Characterization of Anti-Citrinin Specific ScFvs Selected from Non-Immunized Mouse Splenocytes by Eukaryotic Ribosome Display. PLoS One 2015; 10:e0131482. [PMID: 26131718 PMCID: PMC4488840 DOI: 10.1371/journal.pone.0131482] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 06/01/2015] [Indexed: 11/19/2022] Open
Abstract
Single chain variable fragments (scFvs) against citrinin (CIT) were selected from a scFv library constructed from the splenocytes of non-immunized mice by an improved eukaryotic ribosome display technology in this study. Bovine serum albumin (BSA)/ CIT-BSA and ovalbumin (OVA)/ CIT-OVA were used as the antigens to select specific anti-CIT scFvs. Eukaryotic in situ RT-PCR method was used to recover the selected mRNA after every affinity selection. After six rounds of ribosome display, expression vector pTIG-TRX carrying specific scFv DNAs were constructed and transformed into Escherichia coli BL21 (DE3) for protein expression. Thirteen positive clones were selected out of which three (designated 23, 68 and 109) showed high binding activity and specificity to CIT by indirect ELISA, while no clone showed binding activity with carrier proteins. The three scFvs showed high specificity to CIT and the cross reactivity with other mycotoxins was below 0.01% as determined by indirect competitive ELISA. These specific scFvs offer a potential novel immunoassay method for CIT residues. This study confirmed the effectiveness of the improved eukaryotic ribosome display system and could be used as a reference for the selection of scFvs specific to other small molecules using ribosome display.
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Wang R, Xiang S, Feng Y, Srinivas S, Zhang Y, Lin M, Wang S. Engineering production of functional scFv antibody in E. coli by co-expressing the molecule chaperone Skp. Front Cell Infect Microbiol 2013; 3:72. [PMID: 24224158 PMCID: PMC3818579 DOI: 10.3389/fcimb.2013.00072] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 10/16/2013] [Indexed: 11/20/2022] Open
Abstract
Single-chain variable fragment (scFv) is a class of engineered antibodies generated by the fusion of the heavy (VH) and light chains (VL) of immunoglobulins through a short polypeptide linker. ScFv play a critical role in therapy and diagnosis of human diseases, and may in fact also be developed into a potential diagnostic and/or therapeutic agent. However, the fact that current scFv antibodies have poor stability, low solubility, and affinity, seriously limits their diagnostic and clinical implication. Here we have developed four different expression vectors, and evaluated their abilities to express a soluble scFv protein. The solubility and binding activity of the purified proteins were determined using both SDS-PAGE and ELISA. Amongst the four purified proteins, the Skp co-expressed scFv showed the highest solubility, and the binding activity to antigen TLH was 3-4 fold higher than the other three purified scFv. In fact, this scFv is specific for TLH and does not cross-react with other TLH-associated proteins and could be used to detect TLH directly in real samples. These results suggest that the pACYC-Duet-skp co-expression vector might be a useful tool for the production of soluble and functional scFv antibody.
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Affiliation(s)
- Rongzhi Wang
- The Ministry of Education Key Laboratory of Biopesticide and Chemical Biology, College of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
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XIN LIN, CAO JIAQING, LIU CHUAN, ZENG FEI, CHENG HUA, HU XIAOYUN, ZHU PEIQIAN, SHAO JIANGHUA. Selection of anti-cancer-associated gene single-chain variable fragments derived from gastric cancer patients using ribosome display. Mol Med Rep 2013; 8:631-7. [DOI: 10.3892/mmr.2013.1502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 05/20/2013] [Indexed: 11/06/2022] Open
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Selection of Single Chain Variable Fragments Specific for the Human-Inducible Costimulator Using Ribosome Display. Appl Biochem Biotechnol 2012; 168:967-79. [DOI: 10.1007/s12010-012-9800-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Accepted: 07/03/2012] [Indexed: 12/13/2022]
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Screening for a single-chain variable-fragment antibody that can effectively neutralize the cytotoxicity of the Vibrio parahaemolyticus thermolabile hemolysin. Appl Environ Microbiol 2012; 78:4967-75. [PMID: 22562997 DOI: 10.1128/aem.00435-12] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio parahaemolyticus is a halophilic bacterium that is widely distributed in water resources. The bacterium causes lethal food-borne diseases and poses a serious threat to human and animal health all over the world. The major pathogenic factor of V. parahaemolyticus is thermolabile hemolysin (TLH), encoded by the tlh gene, but its toxicity mechanisms are unknown. A high-affinity antibody that can neutralize TLH activity effectively is not available. In this study, we successfully expressed and purified the TLH antigen and discovered a high-affinity antibody to TLH, named scFv-LA3, by phage display screening. Cytotoxicity analysis showed that scFv-LA3 has strong neutralization effects on TLH-induced cell toxicity.
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Luo Y, Xia Y. Selection of single-chain variable fragment antibodies against fenitrothion by ribosome display. Anal Biochem 2012; 421:130-7. [DOI: 10.1016/j.ab.2011.10.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 10/01/2011] [Accepted: 10/25/2011] [Indexed: 11/25/2022]
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Liu J, Ning B, Liu M, Sun Y, Sun Z, Zhang Y, Fan X, Zhou Z, Gao Z. Construction of ribosome display library based on lipocalin scaffold and screening anticalins with specificity for estradiol. Analyst 2012; 137:2470-9. [DOI: 10.1039/c2an16119b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Yang T, Yang L, Chai W, Li R, Xie J, Niu B. A strategy for high-level expression of a single-chain variable fragment against TNFα by subcloning antibody variable regions from the phage display vector pCANTAB 5E into pBV220. Protein Expr Purif 2011; 76:109-14. [DOI: 10.1016/j.pep.2010.10.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 10/08/2010] [Accepted: 10/08/2010] [Indexed: 10/18/2022]
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Abstract
The aim of this study was to construct a ribosome display library of single chain variable fragments (scFvs) associated with hepatocarcinoma and screen such a library for hepatocarcinoma-binding scFvs. mRNA was isolated from the spleens of mice immunized with hepatocellular carcinoma cell line HepG2. Heavy and k chain genes (VH and k) were amplified separately by RT-PCR, and an anti-HepG2 VH/k chain ribosome display library was constructed by assembling VH and k into the VH/k chain with a specially constructed linker by SOE-PCR. The VH/k chain library was transcribed and translated in vitro using a rabbit reticulocyte lysate system. In order to isolate specific scFvs, recognizing HepG2 negative selection on a normal hepatocyte line WRL-68 was carried out before three rounds of positive selection on HepG2. After three rounds of panning, cell enzyme-linked immunosorbent assay (ELISA) showed that one of the scFvs had high affinity for the HepG2 cell and lower affinity for the WRL-68 cell. In this study, we successfully constructed a native ribosome display library. Such a library would prove useful for direct intact cell panning using ribosome display technology. The selected scFv had a potential value for hepatocarcinoma treatment.
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Qi Y, Wu C, Zhang S, Wang Z, Huang S, Dai L, Wang S, Xia L, Wen K, Cao X, Wu Y, Shen J. Selection of anti-sulfadimidine specific ScFvs from a hybridoma cell by eukaryotic ribosome display. PLoS One 2009; 4:e6427. [PMID: 19641611 PMCID: PMC2712767 DOI: 10.1371/journal.pone.0006427] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2009] [Accepted: 06/19/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Ribosome display technology has provided an alternative platform technology for the development of novel low-cost antibody based on evaluating antibiotics derived residues in food matrixes. METHODOLOGY/PRINCIPAL FINDINGS In our current studies, the single chain variable fragments (scFvs) were selected from hybridoma cell lines against sulfadimidine (SM(2)) by using a ribosome library technology. A DNA library of scFv antibody fragments was constructed for ribosome display, and then mRNA-ribosome-antibody (MRA) complexes were produced by a rabbit reticulocyte lysate system. The synthetic sulfadimidine-ovalbumin (SM(2)-OVA) was used as an antigen to pan MRA complexes and putative scFv-encoding genes were recovered by RT-PCR in situ following each panning. After four rounds of ribosome display, the expression vector pCANTAB5E containing the selected specific scFv DNA was constructed and transformed into Escherichia coli HB2151. Three positive clones (SAS14, SAS68 and SAS71) were screened from 100 clones and had higher antibody activity and specificity to SM(2) by indirect ELISA. The three specific soluble scFvs were identified to be the same molecular weight (approximately 30 kDa) by Western-blotting analysis using anti-E tag antibodies, but they had different amino acids sequence by sequence analysis. CONCLUSIONS/SIGNIFICANCE The selection of anti-SM(2) specific scFv by in vitro ribosome display technology will have an important significance for the development of novel immunodetection strategies for residual veterinary drugs.
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Affiliation(s)
- Yonghua Qi
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
- College of Animal Science, Henan Institute of Science and Technology, Xixiang, China
| | - Congming Wu
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Suxia Zhang
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Zhanhui Wang
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Siyang Huang
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Lei Dai
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Shaochen Wang
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Lining Xia
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
- College of Veterinary Medicine, Xinjiang Agricultural University, Urmuqi, China
| | - Kai Wen
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Xingyuan Cao
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Yongning Wu
- Institute for Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jianzhong Shen
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, China
- * E-mail:
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Weisser NE, Hall JC. Applications of single-chain variable fragment antibodies in therapeutics and diagnostics. Biotechnol Adv 2009; 27:502-20. [PMID: 19374944 DOI: 10.1016/j.biotechadv.2009.04.004] [Citation(s) in RCA: 175] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Revised: 03/03/2009] [Accepted: 04/04/2009] [Indexed: 11/18/2022]
Abstract
Antibodies (Abs) are some of the most powerful tools in therapy and diagnostics and are currently one of the fastest growing classes of therapeutic molecules. Recombinant antibody (rAb) fragments are becoming popular therapeutic alternatives to full length monoclonal Abs since they are smaller, possess different properties that are advantageous in certain medical applications, can be produced more economically and are easily amendable to genetic manipulation. Single-chain variable fragment (scFv) Abs are one of the most popular rAb format as they have been engineered into larger, multivalent, bi-specific and conjugated forms for many clinical applications. This review will show the tremendous versatility and importance of scFv fragments as they provide the basic antigen binding unit for a multitude of engineered Abs for use as human therapeutics and diagnostics.
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Affiliation(s)
- Nina E Weisser
- Department of Environmental Biology, University of Guelph, Guelph, ON N1G2W1, Canada
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Rich RL, Myszka DG. Survey of the year 2007 commercial optical biosensor literature. J Mol Recognit 2008; 21:355-400. [DOI: 10.1002/jmr.928] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Friedman M, Orlova A, Johansson E, Eriksson TLJ, Höidén-Guthenberg I, Tolmachev V, Nilsson FY, Ståhl S. Directed evolution to low nanomolar affinity of a tumor-targeting epidermal growth factor receptor-binding affibody molecule. J Mol Biol 2008; 376:1388-402. [PMID: 18207161 DOI: 10.1016/j.jmb.2007.12.060] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Revised: 12/20/2007] [Accepted: 12/21/2007] [Indexed: 12/20/2022]
Abstract
The epidermal growth factor receptor 1 (EGFR) is overexpressed in various malignancies and is associated with a poor patient prognosis. A small, receptor-specific, high-affinity imaging agent would be a useful tool in diagnosing malignant tumors and in deciding upon treatment and assessing the response to treatment. We describe here the affinity maturation procedure for the generation of Affibody molecules binding with high affinity and specificity to EGFR. A library for affinity maturation was constructed by rerandomization of selected positions after the alignment of first-generation binding variants. New binders were selected with phage display technology, using a single oligonucleotide in a single-library effort, and the best second-generation binders had an approximately 30-fold improvement in affinity (K(d)=5-10 nM) for the soluble extracellular domain of EGFR in biospecific interaction analysis using Biacore. The dissociation equilibrium constant, K(d), was also determined for the Affibody with highest affinity using EGFR-expressing A431 cells in flow cytometric analysis (K(d)=2.8 nM). A retained high specificity for EGFR was verified by a dot blot assay showing staining only of EGFR proteins among a panel of serum proteins and other EGFR family member proteins (HER2, HER3, and HER4). The EGFR-binding Affibody molecules were radiolabeled with indium-111, showing specific binding to EGFR-expressing A431 cells and successful targeting of the A431 tumor xenografts with 4-6% injected activity per gram accumulated in the tumor 4 h postinjection.
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Affiliation(s)
- Mikaela Friedman
- Department of Molecular Biotechnology, AlbaNova University Center, Kungl Tekniska Högskolan (KTH), SE-106 91 Stockholm, Sweden
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