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High-Efficiency Bovine Sperm Sexing Used Magnetic-Activated Cell Sorting by Coupling scFv Antibodies Specific to Y-Chromosome-Bearing Sperm on Magnetic Microbeads. BIOLOGY 2022; 11:biology11050715. [PMID: 35625442 PMCID: PMC9138659 DOI: 10.3390/biology11050715] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/29/2022] [Accepted: 05/04/2022] [Indexed: 11/17/2022]
Abstract
Sperm sexing technique is favored in the dairy industry. This research focuses on the efficiency of bovine sperm sexing using magnetic-activated cell sorting (MACS) by scFv antibody against Y-chromosome-bearing sperm (Y-scFv) coupled to magnetic microbeads and its effects on kinematic variables, sperm quality, and X/Y-sperm ratio. In this study, the optimal concentration of Y-scFv antibody coupling to the surface of magnetic microbeads was 2–4 mg/mL. PY-microbeads revealed significantly enriched Y-chromosome-bearing sperm (Y-sperm) in the eluted fraction (78.01–81.43%) and X-chromosome-bearing sperm (X-sperm) in the supernatant fraction (79.04–82.65%). The quality of frozen–thawed sexed sperm was analyzed by CASA and imaging flow cytometer, which showed that PY-microbeads did not have a negative effect on X-sperm motility, viability, or acrosome integrity. However, sexed Y-sperm had significantly decreased motility and viability. The X/Y-sperm ratio was determined using an imaging flow cytometer and real-time PCR. PY-microbeads produced sperm with up to 82.65% X-sperm in the X-enriched fraction and up to 81.43% Y-sperm in the Y-enriched fraction. Bovine sperm sexing by PY-microbeads showed high efficiency in separating Y-sperm from X-sperm and acceptable sperm quality. This initial technique is feasible for bovine sperm sexing, which increases the number of heifers in dairy herds while lowering production expenses.
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Zhang L, Cao Y, Liu M, Chen X, Xiang Q, Tian J. Functional recombinant single-chain variable fragment antibody against Agkistrodon acutus venom. Exp Ther Med 2019; 17:3768-3774. [PMID: 30988762 DOI: 10.3892/etm.2019.7348] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 04/11/2018] [Indexed: 11/06/2022] Open
Abstract
Agkistrodon acutus bites are conventionally treated with animal-derived antivenom, the use of which is limited due to allergic reactions and serum sickness. Thus in the present study, the genes of humanized antibodies produced in response to A. acutus venom were extracted from lymphocytes from patients bitten by A. acutus. A single-chain variable fragment (scFv) library against venom was constructed using a T7 phage display system. ScFv genes that exhibited high affinity to venom were selected by library biopanning. An expression system was constructed for antivenom scFv fused with 6×His tag at its N- and C-terminus using pET-28a (+) vector. The scFv proteins could achieve functional and soluble expression in Escherichia coli via the auto-induction method. The purity and activity of the scFv genes and proteins were confirmed by SDS-PAGE, western blotting and ELISA. The results indicated that three soluble scFv proteins exhibited specific affinity to A. acutus venom and were harvested via the auto-induction method.
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Affiliation(s)
- Lei Zhang
- Department of Emergency, Southwest Hospital of the Third Military Medical University, Chongqing 400038, P.R. China
| | - Yuliang Cao
- Department of Emergency, Southwest Hospital of the Third Military Medical University, Chongqing 400038, P.R. China
| | - Minghua Liu
- Department of Emergency, Southwest Hospital of the Third Military Medical University, Chongqing 400038, P.R. China
| | - Xiangyu Chen
- Department of Emergency, Southwest Hospital of the Third Military Medical University, Chongqing 400038, P.R. China
| | - Qiang Xiang
- Department of Emergency, Southwest Hospital of the Third Military Medical University, Chongqing 400038, P.R. China
| | - Jun Tian
- Department of Emergency, Southwest Hospital of the Third Military Medical University, Chongqing 400038, P.R. China
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Burgess RR. Gentle antibody-mimetic affinity chromatography with polyol-responsive nanoCLAMPs. Protein Expr Purif 2017. [PMID: 28633910 DOI: 10.1016/j.pep.2017.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Richard R Burgess
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, United States
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Development of polyol-responsive antibody mimetics for single-step protein purification. Protein Expr Purif 2017; 134:114-124. [DOI: 10.1016/j.pep.2017.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 04/13/2017] [Accepted: 04/15/2017] [Indexed: 12/11/2022]
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Ossysek K, Uchański T, Kulesza M, Bzowska M, Klaus T, Woś K, Madej M, Bereta J. A new expression vector facilitating production and functional analysis of scFv antibody fragments selected from Tomlinson I + J phagemid libraries. Immunol Lett 2015. [DOI: 10.1016/j.imlet.2015.07.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Ozaki CY, Silveira CRF, Andrade FB, Nepomuceno R, Silva A, Munhoz DD, Yamamoto BB, Luz D, Abreu PAE, Horton DSPQ, Elias WP, Ramos OHP, Piazza RMF. Single Chain Variable Fragments Produced in Escherichia coli against Heat-Labile and Heat-Stable Toxins from Enterotoxigenic E. coli. PLoS One 2015; 10:e0131484. [PMID: 26154103 PMCID: PMC4496030 DOI: 10.1371/journal.pone.0131484] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 06/01/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Diarrhea is a prevalent pathological condition frequently associated to the colonization of the small intestine by enterotoxigenic Escherichia coli (ETEC) strains, known to be endemic in developing countries. These strains can produce two enterotoxins associated with the manifestation of clinical symptoms that can be used to detect these pathogens. Although several detection tests have been developed, minimally equipped laboratories are still in need of simple and cost-effective methods. With the aim to contribute to the development of such diagnostic approaches, we describe here two mouse hybridoma-derived single chain fragment variable (scFv) that were produced in E. coli against enterotoxins of ETEC strains. METHODS AND FINDINGS Recombinant scFv were developed against ETEC heat-labile toxin (LT) and heat-stable toxin (ST), from previously isolated hybridoma clones. This work reports their design, construction, molecular and functional characterization against LT and ST toxins. Both antibody fragments were able to recognize the cell-interacting toxins by immunofluorescence, the purified toxins by ELISA and also LT-, ST- and LT/ST-producing ETEC strains. CONCLUSION The developed recombinant scFvs against LT and ST constitute promising starting point for simple and cost-effective ETEC diagnosis.
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Affiliation(s)
| | | | | | | | - Anderson Silva
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, SP, Brasil
| | | | - Bruno B. Yamamoto
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, SP, Brasil
| | - Daniela Luz
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, SP, Brasil
| | | | | | - Waldir P. Elias
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, SP, Brasil
| | | | - Roxane M. F. Piazza
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, SP, Brasil
- * E-mail:
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Zou L, Xu Y, Li Y, He Q, Chen B, Wang D. Development of a single-chain variable fragment antibody-based enzyme-linked immunosorbent assay for determination of fumonisin B₁ in corn samples. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2014; 94:1865-1871. [PMID: 24375282 DOI: 10.1002/jsfa.6505] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Revised: 11/13/2013] [Accepted: 11/28/2013] [Indexed: 06/03/2023]
Abstract
BACKGROUND Fumonisin B1 (FB1 ) is a cancer-promoting mycotoxin produced by Fusarium species and one of the major food-borne toxins in corn and corn products. The objective of this study was to produce a single-chain variable fragment (scFv) antibody for determination of FB1 in corn samples. RESULTS Anti-FB1 monoclonal antibodies were obtained via the hybridoma technique. Specific heavy- and light-chain variable fragments were amplified with degenerate primers and constructed into scFv antibody fragments by splice overlap extension polymerase chain reaction with linker sequences. The resulting scFv DNA fragments were cloned into the phagemid pHEN1for selection and identification of functional scFv fragment by phage display. Prokaryotic expression vector pET22b-scFv was constructed to prepare anti-FB1 scFv antibody for establishment of indirect competitive ELISA. The detection capability (CCβ) of the scFv-based ELISA was 15.00 µg kg(-1), and the limit of detection was 8.32 µg kg(-1). The recoveries and coefficients of variation were 86.74-107.34% and 9.72-14.03%, respectively. In addition, the determined results of 30 naturally contaminated corn samples by the scFv-based ELISA are in agreement with the findings of high-performance liquid chromatography (R(2) = 0.97). CONCLUSION This scFv-based ELISA could be used as an efficient screening method for routine monitoring the residues FB1 in corn samples.
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Affiliation(s)
- Long Zou
- State Key Laboratory of Food Science and Technology, Sino-Germany Joint Research Institute, Nanchang University, Nanchang, 330047, China
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Chen M, Wen K, Tao X, Xie J, Wang L, Li Y, Ding S, Jiang H. Cloning, expression, purification and characterization of a bispecific single-chain diabody against fluoroquinolones and sulfonamides in Escherichia coli. Protein Expr Purif 2014; 100:19-25. [PMID: 24816423 DOI: 10.1016/j.pep.2014.04.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Revised: 04/28/2014] [Accepted: 04/29/2014] [Indexed: 11/30/2022]
Abstract
A recombinant bispecific single-chain diabody (scDb), recognizing fluoroquinolones (FQs) and sulfonamides (SAs), was successfully constructed with two single-chain variable fragment antibodies (scFvs). The scDb gene was cloned into the expression vector pJB33, and 6×His-tagged scDb was expressed as soluble bodies in Escherichia coli RV308 host, then purified by one step affinity chromatography of immobilized metal ion affinity chromatography (IMAC). SDS-PAGE and Western blotting analysis of the purified scDb indicated that the prepared scDb was successfully expressed as a ∼60 kDa and the final purity of the scDb protein was up to 95% with yields of approximately 6 mg/L of bacterial culture. The scDb was further characterized by indirect competitive enzyme linked immunosorbent assay (icELISA), showing that the affinity and specificity of scDb were fully retained from the two parental scFvs, capable of simultaneously binding FQs and SAs. The 50% inhibition concentration (IC50) values of the optimized immunoassay were 0.45 ng mL(-1) for FQs and 0.75 ng mL(-1) for SAs, respectively. The scDb exhibited high affinity to 20 FQs and 14 SAs. Taken together, these findings suggested that the prepared scDb could be used to develop future novel immunoassay for simultaneous determination of 20 FQs and 14 SAs.
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Affiliation(s)
- Min Chen
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Kai Wen
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Xiaoqi Tao
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Jie Xie
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Limiao Wang
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Yang Li
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Shuangyang Ding
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Haiyang Jiang
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
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Drees JJ, Augustin LB, Mertensotto MJ, Schottel JL, Leonard AS, Saltzman DA. Soluble production of a biologically active single-chain antibody against murine PD-L1 in Escherichia coli. Protein Expr Purif 2014; 94:60-6. [DOI: 10.1016/j.pep.2013.10.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 10/29/2013] [Accepted: 10/31/2013] [Indexed: 10/26/2022]
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Cloning, expression, purification, and characterization of a novel single-chain variable fragment antibody against the 2-nitrobenzaldehyde derivative of a furaltadone metabolite in Escherichia coli. Protein Expr Purif 2012; 84:140-6. [DOI: 10.1016/j.pep.2012.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 05/03/2012] [Accepted: 05/06/2012] [Indexed: 10/28/2022]
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Dang S, Hong T, Ding BS, Zhang W. A humanized single-chain variable fragment antibody against beta3 integrin in Escherichia coli. Hybridoma (Larchmt) 2012; 30:543-8. [PMID: 22149280 DOI: 10.1089/hyb.2011.0056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Patients with HIV-1 immune-related thrombocytopenia (HIV-1-ITP) have a unique antibody (Ab) against platelet GPIIIa49-66, which is capable of inducing oxidative platelet fragmentation in the absence of complement activation. By screening a human phage antibody library with the GPIIIa49-66 peptide as bait, we have developed several humanized phage Abs, which act similarly to the parental Ab. However, the presence of a stop codon in the heavy chain of the obtained phage clones limits their expression in soluble recombinant form. To circumvent this problem, we mutated the stop codon inside clone 11 that exhibits the highest binding activity to platelet GPIIIa49-66, resulting in a soluble scFv format (named A11) in Escherichia coli Rosseta. In in vitro binding assay, A11 exhibited similar binding specificity to parental Ab at various concentrations. Moreover, A11 is able to induce oxidative platelet fragmentation by preferentially binding to activated versus resting platelets. These findings provide a proof-of-principle for the development of a novel approach to inhibit arterial thrombosis by generating a selective scFv for the lysis of platelet-rich thrombi.
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Affiliation(s)
- Suying Dang
- Department of Medical Genetics, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China
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Dissolution of arterial platelet thrombi in vivo with a bifunctional platelet GPIIIa49-66 ligand which specifically targets the platelet thrombus. Blood 2010; 116:2336-44. [PMID: 20525921 DOI: 10.1182/blood-2010-01-264358] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Patients with HIV-1 immune-related thrombocytopenia have a unique antibody (Ab) against integrin GPIIIa49-66 capable of inducing oxidative platelet fragmentation via Ab activation of platelet nicotinamide adenine dinucleotide phosphate oxidase and 12-lipoxygenase releasing reactive oxygen species. Using a phage display single-chain antibody (scFv) library, we developed a novel human monoclonal scFv Ab against GPIIIa49-66 (named A11) capable of inducing fragmentation of activated platelets. In this study, we investigated the in vivo use of A11. We show that A11 does not induce significant thrombocytopenia or inhibit platelet function. A11 can prevent the cessation of carotid artery flow produced by induced artery injury and dissolve the induced thrombus 2 hours after cessation of blood flow. In addition, A11 can prevent, as well as ameliorate, murine middle cerebral artery stroke, without thrombocytopenia or brain hemorrhage. To further optimize the antithrombotic activity of A11, we produced a bifunctional A11-plasminogen first kringle agent (SLK), which homes to newly deposited fibrin strands within and surrounding the platelet thrombus, reducing effects on nonactivated circulating platelets. Indeed, SLK is able to completely reopen occluded carotid vessels 4 hours after cessation of blood flow, whereas A11 had no effect at 4 hours. Thus, a new antithrombotic agent was developed for platelet thrombus clearance.
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Kvam E, Sierks MR, Shoemaker CB, Messer A. Physico-chemical determinants of soluble intrabody expression in mammalian cell cytoplasm. Protein Eng Des Sel 2010; 23:489-98. [PMID: 20378699 PMCID: PMC2865363 DOI: 10.1093/protein/gzq022] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 03/02/2010] [Accepted: 03/12/2010] [Indexed: 12/25/2022] Open
Abstract
Soluble antibody fragments are desirable not only as potential therapeutic and diagnostic agents for extracellular targets but also as 'intrabodies' for functional genomics, proteomics and gene therapy inside cells. However, antibody fragments are notoriously aggregation-prone when expressed intracellularly, due in part to unfavorable redox potential and macromolecular crowding in cell cytoplasm. Only a small proportion of intrabodies are soluble in cytoplasm and little is known about the sequence determinants that confer such stability. By comparing the cytoplasmic expression of several related human single-chain variable fragments and camelid V(HH)s in mammalian cells, we report that intrabody solubility is highly influenced by CDR content and is improved by an overall negative charge at cytoplasmic pH and reduced hydrophilicity. We hypothesize that ionic repulsion and weak hydrophobic interactions compensate, to different extents, for impaired disulfide bond formation in cytoplasm, thereby decreasing the risk for intrabody aggregation. As proof of principle, we demonstrate that the soluble expression of an aggregation-prone positively charged intrabody is modestly enhanced via cis or trans acidification using highly charged peptide tags (3XFLAG tag, SV40 NLS). These findings suggest that simple sequence analysis and electrostatic manipulation may aid in predicting and engineering solubility-enhanced intrabodies from antibody libraries for intracellular use.
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Affiliation(s)
- Erik Kvam
- New York State Department of Health, Wadsworth Center/ David Axelrod Institute, 120 New Scotland Ave., PO Box 22002, Albany, NY 12201-2002, USA
- Department of Biomedical Sciences, University at Albany, Albany, NY, USA
| | - Michael R. Sierks
- Department of Chemical Engineering, Arizona State University, Tempe, AZ, USA
| | - Charles B. Shoemaker
- Department of Biomedical Sciences, Tufts Cummings School of Veterinary Medicine, North Grafton, MA, USA
| | - Anne Messer
- New York State Department of Health, Wadsworth Center/ David Axelrod Institute, 120 New Scotland Ave., PO Box 22002, Albany, NY 12201-2002, USA
- Department of Biomedical Sciences, University at Albany, Albany, NY, USA
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Xiong H, Li S, Yang Z, Burgess RR, Dynan WS. E. coli expression of a soluble, active single-chain antibody variable fragment containing a nuclear localization signal. Protein Expr Purif 2009; 66:172-80. [PMID: 19281848 DOI: 10.1016/j.pep.2009.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 02/27/2009] [Accepted: 03/02/2009] [Indexed: 01/10/2023]
Abstract
Single-chain antibody variable fragment (scFv) proteins consist of an antibody heavy chain variable sequence joined via a flexible linker to a light chain variable sequence. Prior work has shown that ScFv 18-2 binds the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and sensitizes cancer cells to radiation following nuclear microinjection. A potential clinical delivery strategy is based on modification of the scFv so that it can be taken up into cells and imported to the nucleus. This will require development of an expression system for a nuclear localization signal (NLS)-tagged scFv derivative. We found, however, that addition of the highly basic NLS severely compromised expression in the host-vector system used for the parental scFv. After testing a variety of host strains, fusion partners, and NLS sequences and placements, successful expression was obtained with a construct containing a stabilizing N-terminal maltose binding protein tag and a single, optimized, C-terminal NLS moiety. Amylose affinity-purified ScFv 18-2 NLS protein was stable to storage at 4 degrees C in the presence of glycerol or trehalose, bound selectively to an epitope peptide, and was cleavable at an engineered Factor Xa protease site. Following lipid-mediated uptake into cultured cells, NLS-tagged ScFv 18-2, unlike the parental ScFv 18-2, localized predominantly in the cell nucleus.
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Affiliation(s)
- Hairong Xiong
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, 1120 15th Street, Augusta, GA 30912, USA
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Chiu C, Wei H, Wu L. Generation and Utilization of P450 Cholesterol Side‐Chain Cleavage Enzyme and 3β‐Hydroxysteroid Dehydrogenase Antibodies for Universal Detection. J Immunoassay Immunochem 2008; 29:152-60. [DOI: 10.1080/15321810801887839] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Ettayebi K, Hardy ME. Recombinant norovirus-specific scFv inhibit virus-like particle binding to cellular ligands. Virol J 2008; 5:21. [PMID: 18237416 PMCID: PMC2267775 DOI: 10.1186/1743-422x-5-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Accepted: 01/31/2008] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Noroviruses cause epidemic outbreaks of gastrointestinal illness in all age-groups. The rapid onset and ease of person-to-person transmission suggest that inhibitors of the initial steps of virus binding to susceptible cells have value in limiting spread and outbreak persistence. We previously generated a monoclonal antibody (mAb) 54.6 that blocks binding of recombinant norovirus-like particles (VLP) to Caco-2 intestinal cells and inhibits VLP-mediated hemagglutination. In this study, we engineered the antigen binding domains of mAb 54.6 into a single chain variable fragment (scFv) and tested whether these scFv could function as cell binding inhibitors, similar to the parent mAb. RESULTS The scFv54.6 construct was engineered to encode the light (VL) and heavy (VH) variable domains of mAb 54.6 separated by a flexible peptide linker, and this recombinant protein was expressed in Pichia pastoris. Purified scFv54.6 recognized native VLPs by immunoblot, inhibited VLP-mediated hemagglutination, and blocked VLP binding to H carbohydrate antigen expressed on the surface of a CHO cell line stably transfected to express alpha 1,2-fucosyltransferase. CONCLUSION scFv54.6 retained the functional properties of the parent mAb with respect to inhibiting norovirus particle interactions with cells. With further engineering into a form deliverable to the gut mucosa, norovirus neutralizing antibodies represent a prophylactic strategy that would be valuable in outbreak settings.
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Affiliation(s)
- Khalil Ettayebi
- Veterinary Molecular Biology, Montana State University, Bozeman, MT 59717, USA
| | - Michele E Hardy
- Veterinary Molecular Biology, Montana State University, Bozeman, MT 59717, USA
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Martins S, Lourenço S, Karmali A, Serralheiro ML. Monoclonal Antibodies Recognize Conformational Epitopes on Wild-type and Recombinant Mutant Amidases from Pseudomonas aeruginosa. Mol Biotechnol 2007; 37:136-45. [PMID: 17914174 DOI: 10.1007/s12033-007-0040-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/26/2022]
Abstract
Hybridoma technology was used to raise monoclonal antibodies (MAbs) against wild-type amidase from Pseudomonas aeruginosa. Hybridoma clones secreting polyol-responsive MAbs (PR-MAbs) were screened that bind antigen tightly. but release under mild- and non-denaturing elution conditions, which can be used as ligands in immunoaffinity chromatography. Two of these hybridoma clones (C9E4 and B1E4) secreting MAbs against wild-type amidase were selected in order to check if they are PR-MAbs by using ELISA-elution assay. These hybridoma cell lines secreted MAbs of IgG class which were purified in a single step by Protein A-Sepharose CL-4B chromatography, which revealed two protein bands on SDS-PAGE. Specificity studies of MAb C9E4 revealed that it recognized a common epitope on wild-type and mutant T103I amidases as determined by direct ELISA, as well as by Western blotting under native conditions. This MAb exhibited a higher-affinity constant (K) for the mutant T103I amidase than for the wild-type enzyme. However, this MAb did not recognize either wild-type or mutant T103I enzymes under denaturing conditions suggesting that it binds to a conformation-sensitive epitope on amidase molecule. On the other hand, it also does not recognize either native or denatured forms of mutant C91A amidase suggesting that this substitution disrupted the conformational epitope present on amidase molecule. Furthermore, MAb C9E4 inhibited about 80% of wild-type amidase activity, whereas it activated about 80% of mutant amidase (T103I) activity. However, this MAb did not affect mutant C91A amidase activity which is in agreement with other results presented in this work. The data presented in this work suggest that this MAb acts as a powerful probe to detect conformational changes in native and denatured amidases as well as to differentiate wild-type and mutant (T103I and C91A) amidases.
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Affiliation(s)
- Sónia Martins
- Centro de Investigação de Engenharia Química e Biotecnologia, Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emídio Navarro, Lisbon, 1950-062, Portugal
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