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Martin-Alonso C, Tabrizi S, Xiong K, Blewett T, Sridhar S, Crnjac A, Patel S, An Z, Bekdemir A, Shea D, Wang ST, Rodriguez-Aponte S, Naranjo CA, Rhoades J, Kirkpatrick JD, Fleming HE, Amini AP, Golub TR, Love JC, Bhatia SN, Adalsteinsson VA. Priming agents transiently reduce the clearance of cell-free DNA to improve liquid biopsies. Science 2024; 383:eadf2341. [PMID: 38236959 DOI: 10.1126/science.adf2341] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 12/01/2023] [Indexed: 01/23/2024]
Abstract
Liquid biopsies enable early detection and monitoring of diseases such as cancer, but their sensitivity remains limited by the scarcity of analytes such as cell-free DNA (cfDNA) in blood. Improvements to sensitivity have primarily relied on enhancing sequencing technology ex vivo. We sought to transiently augment the level of circulating tumor DNA (ctDNA) in a blood draw by attenuating its clearance in vivo. We report two intravenous priming agents given 1 to 2 hours before a blood draw to recover more ctDNA. Our priming agents consist of nanoparticles that act on the cells responsible for cfDNA clearance and DNA-binding antibodies that protect cfDNA. In tumor-bearing mice, they greatly increase the recovery of ctDNA and improve the sensitivity for detecting small tumors.
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Affiliation(s)
- Carmen Martin-Alonso
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Harvard-MIT Division of Health Sciences and Technology, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Shervin Tabrizi
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA 02114, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Kan Xiong
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Timothy Blewett
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Andjela Crnjac
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Sahil Patel
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Division of Pulmonary and Critical Care, Department of Medicine, Massachusetts General Hospital, Boston, MA 02124, USA
| | - Zhenyi An
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Ahmet Bekdemir
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Douglas Shea
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Shih-Ting Wang
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sergio Rodriguez-Aponte
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Christopher A Naranjo
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Justin Rhoades
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jesse D Kirkpatrick
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Harvard-MIT Division of Health Sciences and Technology, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Heather E Fleming
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ava P Amini
- Microsoft Research, Cambridge, MA 02142, USA
| | - Todd R Golub
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Harvard Medical School, Boston, MA 02115, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - J Christopher Love
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sangeeta N Bhatia
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Harvard-MIT Division of Health Sciences and Technology, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
- Wyss Institute at Harvard University, Boston, MA 02215, USA
- Howard Hughes Medical Institute, Cambridge, MA 02138, USA
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2
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Tabrizi S, Martin-Alonso C, Xiong K, Blewett T, Sridhar S, An Z, Patel S, Rodriguez-Aponte S, Naranjo CA, Wang ST, Shea D, Golub TR, Bhatia SN, Adalsteinsson V, Love JC. An intravenous DNA-binding priming agent protects cell-free DNA and improves the sensitivity of liquid biopsies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.13.523947. [PMID: 36711455 PMCID: PMC9882106 DOI: 10.1101/2023.01.13.523947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Blood-based, or "liquid," biopsies enable minimally invasive diagnostics but have limits on sensitivity due to scarce cell-free DNA (cfDNA). Improvements to sensitivity have primarily relied on enhancing sequencing technology ex vivo . Here, we sought to augment the level of circulating tumor DNA (ctDNA) detected in a blood draw by attenuating the clearance of cfDNA in vivo . We report a first-in-class intravenous DNA-binding priming agent given 2 hours prior to a blood draw to recover more cfDNA. The DNA-binding antibody minimizes nuclease digestion and organ uptake of cfDNA, decreasing its clearance at 1 hour by over 150-fold. To improve plasma persistence and limit potential immune interactions, we abrogated its Fc-effector function. We found that it protects GC-rich sequences and DNase-hypersensitive sites, which are ordinarily underrepresented in cfDNA. In tumor-bearing mice, priming improved tumor DNA recovery by 19-fold and sensitivity for detecting cancer from 6% to 84%. These results suggest a novel method to enhance the sensitivity of existing DNA-based cancer testing using blood biopsies.
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3
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Buzzo JR, Devaraj A, Gloag ES, Jurcisek JA, Robledo-Avila F, Kesler T, Wilbanks K, Mashburn-Warren L, Balu S, Wickham J, Novotny LA, Stoodley P, Bakaletz LO, Goodman SD. Z-form extracellular DNA is a structural component of the bacterial biofilm matrix. Cell 2021; 184:5740-5758.e17. [PMID: 34735796 DOI: 10.1016/j.cell.2021.10.010] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 08/03/2021] [Accepted: 10/12/2021] [Indexed: 12/30/2022]
Abstract
Biofilms are community architectures adopted by bacteria inclusive of a self-formed extracellular matrix that protects resident bacteria from diverse environmental stresses and, in many species, incorporates extracellular DNA (eDNA) and DNABII proteins for structural integrity throughout biofilm development. Here, we present evidence that this eDNA-based architecture relies on the rare Z-form. Z-form DNA accumulates as biofilms mature and, through stabilization by the DNABII proteins, confers structural integrity to the biofilm matrix. Indeed, substances known to drive B-DNA into Z-DNA promoted biofilm formation whereas those that drive Z-DNA into B-DNA disrupted extant biofilms. Importantly, we demonstrated that the universal bacterial DNABII family of proteins stabilizes both bacterial- and host-eDNA in the Z-form in situ. A model is proposed that incorporates the role of Z-DNA in biofilm pathogenesis, innate immune response, and immune evasion.
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Affiliation(s)
- John R Buzzo
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Aishwarya Devaraj
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Erin S Gloag
- Department of Orthopedics, Ohio State University, Columbus, OH 43210, USA
| | - Joseph A Jurcisek
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Frank Robledo-Avila
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Theresa Kesler
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Kathryn Wilbanks
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Lauren Mashburn-Warren
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Sabarathnam Balu
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Joseph Wickham
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Laura A Novotny
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Paul Stoodley
- Department of Orthopedics, Ohio State University, Columbus, OH 43210, USA; Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH 43210, USA; National Centre for Advanced Tribology at Southampton, University of Southampton, Southampton S017 1BJ, UK
| | - Lauren O Bakaletz
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA; Department of Pediatrics, College of Medicine, Ohio State University, Columbus, OH 43210, USA.
| | - Steven D Goodman
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA; Department of Pediatrics, College of Medicine, Ohio State University, Columbus, OH 43210, USA.
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4
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Moser AC, Trenhaile S, Frankenberg K. Studies of antibody-antigen interactions by capillary electrophoresis: A review. Methods 2018; 146:66-75. [DOI: 10.1016/j.ymeth.2018.03.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/08/2018] [Accepted: 03/13/2018] [Indexed: 11/25/2022] Open
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5
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Poulsen NN, Pedersen ME, Østergaard J, Petersen NJ, Nielsen CT, Heegaard NHH, Jensen H. Flow-Induced Dispersion Analysis for Probing Anti-dsDNA Antibody Binding Heterogeneity in Systemic Lupus Erythematosus Patients: Toward a New Approach for Diagnosis and Patient Stratification. Anal Chem 2016; 88:9056-61. [DOI: 10.1021/acs.analchem.6b01741] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Nicklas N. Poulsen
- Department
of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Morten E. Pedersen
- Department
of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Jesper Østergaard
- Department
of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Nickolaj J. Petersen
- Department
of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Christoffer T. Nielsen
- Department of Autoimmunology & Biomarkers, Statens Serum Institut, Artillerivej 5, 2300 Copenhagen, Denmark
| | - Niels H. H. Heegaard
- Department of Autoimmunology & Biomarkers, Statens Serum Institut, Artillerivej 5, 2300 Copenhagen, Denmark
- Department
of Clinicial Biochemistry, Odense University Hospital, University of Southern Denmark, Sdr. Boulevard 29, 5000 Odense, Denmark
| | - Henrik Jensen
- Department
of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
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6
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Plesa C, Ruitenberg JW, Witteveen MJ, Dekker C. Detection of Individual Proteins Bound along DNA Using Solid-State Nanopores. NANO LETTERS 2015; 15:3153-8. [PMID: 25928590 DOI: 10.1021/acs.nanolett.5b00249] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
DNA in cells is heavily covered with all types of proteins that regulate its genetic activity. Detection of DNA-bound proteins is a challenge that is well suited to solid-state nanopores as they provide a linear readout of the DNA and DNA-protein volume in the pore constriction along the entire length of a molecule. Here, we demonstrate that we can realize the detection of even individual DNA-bound proteins at the single-DNA-molecule level using solid-state nanopores. We introduce and use a new model system of anti-DNA antibodies bound to lambda phage DNA. This system provides several advantages since the antibodies bind individually, tolerate high salt concentrations, and will, because of their positive charge, not translocate through the pore unless bound to the DNA. Translocation of DNA-antibody samples reveals the presence of short 12 μs current spikes within the DNA traces, with amplitudes that are about 4.5 times larger than that of dsDNA, which are associated with individual antibodies. We conclude that transient interactions between the pore and the antibodies are the primary mechanism by which bound antibodies are observed. This work provides a proof-of-concept for how nanopores could be used for future sensing applications.
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Affiliation(s)
- Calin Plesa
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Justus W Ruitenberg
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Menno J Witteveen
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
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Hu Z, Leppla SH, Li B, Elkins CA. Antibodies specific for nucleic acids and applications in genomic detection and clinical diagnostics. Expert Rev Mol Diagn 2014; 14:895-916. [PMID: 25014728 DOI: 10.1586/14737159.2014.931810] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Detection of nucleic acids using antibodies is uncommon. This is in part because nucleic acids are poor immunogens and it is difficult to elicit antibodies having high affinity to each type of nucleic acid while lacking cross-reactivity to others. We describe the origins and applications of a variety of anti-nucleic acid antibodies, including ones reacting with modified nucleosides and nucleotides, single-stranded DNA, double-stranded DNA, RNA, DNA:RNA hybrids, locked-nucleic acids or peptide nucleic acid:nucleic acid hybrids. Carefully selected antibodies can be excellent reagents for detecting bacteria, viruses, small RNAs, microRNAs, R-loops, cancer cells, stem cells, apoptotic cells and so on. The detection may be sensitive, simple, rapid, specific, reproducible, quantitative and cost-effective. Current microarray and diagnostic methods that depend on cDNA or cRNA can be replaced by using antibody detection of nucleic acids. Therefore, development should be encouraged to explore new utilities and create a robust arsenal of new anti-nucleic acid antibodies.
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Affiliation(s)
- Zonglin Hu
- Winchester Engineering & Analytical Center, Office of Regulatory Affairs, US Food and Drug Administration, 109 Holton Street, Winchester, MA 01890, USA
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8
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Kapil MA, Herr AE. Binding Kinetic Rates Measured via Electrophoretic Band Crossing in a Pseudohomogeneous Format. Anal Chem 2014; 86:2601-9. [DOI: 10.1021/ac403829z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Monica A. Kapil
- Department
of Bioengineering, University of California, Berkeley, California, 94706, United States
| | - Amy E. Herr
- Department
of Bioengineering, University of California, Berkeley, California, 94706, United States
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9
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Kiessig S, Stettler A, Fuhrimann S, Schwarz MA. Affinity Capillary Electrophoresis as a Tool to Characterize Intermolecular Interactions. Supramol Chem 2012. [DOI: 10.1002/9780470661345.smc035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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10
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Ricci F, Adornetto G, Moscone D, Plaxco KW, Palleschi G. Quantitative, reagentless, single-step electrochemical detection of anti-DNA antibodies directly in blood serum. Chem Commun (Camb) 2010; 46:1742-4. [PMID: 20177635 PMCID: PMC3082467 DOI: 10.1039/b922595a] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here we demonstrate the use of redox labeled double- and single-stranded oligonucleotides as recognition probes for the reagentless, single-step, electrochemical detection of anti-DNA antibodies directly in blood serum.
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Affiliation(s)
- Francesco Ricci
- University of Rome Tor Vergata, Dipartimento di Scienze e Tecnologie Chimiche, Via della Ricerca Scientifica, 00133, Rome, Italy
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11
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Buhl A, Page S, Heegaard NHH, von Landenberg P, Luppa PB. Optical biosensor-based characterization of anti-double-stranded DNA monoclonal antibodies as possible new standards for laboratory tests. Biosens Bioelectron 2009; 25:198-203. [PMID: 19632822 DOI: 10.1016/j.bios.2009.06.037] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Revised: 06/24/2009] [Accepted: 06/25/2009] [Indexed: 10/20/2022]
Abstract
The serum determination of circulating anti-double-stranded (ds)DNA autoantibodies is a routine measure for the laboratory diagnosis of systemic lupus erythematosus. Since available assays differ substantially and no feasible calibrator is available, the aim of this study was to evaluate a recently introduced surface plasmon resonance (SPR) biosensor chip for binding studies between dsDNA and anti-dsDNA autoantibodies and to demonstrate its usefulness for the characterization of new monoclonal antibody (mAb) standards and standardization of assays. We characterized two human and one murine monoclonal anti-dsDNA antibodies by measuring the kinetic on- and off-rates using the biosensor and calculating functional affinity (avidity) as the ratio of these. Obtained equilibrium dissociation constants were verified by an independent method and inhibition experiments were performed to determine reactivities to DNA of various length and composition. While all mAbs exhibited comparable avidities, which could be confirmed by gel shift experiments, one of them proved to have slower association and dissociation kinetics. This was the only mAb providing positive results in the Farr RIA. In inhibition experiments with ss- and ds-oligonucleotides 10, 24 and 42 bp in length, the mAbs acted substantially different. The study demonstrates how putative standards for the anti-dsDNA determination can be characterized using SPR biosensor technology. Our results suggest that kinetic rate constants seem to be decisive in explaining the behaviour of mAbs. Different reactivities to various DNA species should be taken into account with respect to varying DNA sources in commonly used laboratory assays.
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Affiliation(s)
- Alexander Buhl
- Institut für Klinische Chemie und Pathobiochemie, Klinikum rechts der Isar der Technischen Universität München, Ismaninger Strasse 22, D-81675 München, Germany
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12
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13
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Analysis of proteins in solution using affinity capillary electrophoresis. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2008. [PMID: 18826064 DOI: 10.1007/978-1-59745-582-4_21] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Analysis of protein interactions by means of capillary electrophoresis (CE) has unique challenges and rewards. The choice of analysis conditions, especially involving electrophoresis buffers, are crucial and not universal for protein analysis. If conditions for analysis can be worked out, it is possible to utilize CE quantitatively and qualitatively to characterize protein-ligand binding involving unmodified molecules in solution and taking place under physiological conditions. This chapter deals with the most important practical considerations in capillary electrophoretic affinity approaches, affinity CE (ACE). The text emphasizes the most critical factors for successful analyses and has application examples illustrating various types of information offered by ACE-based studies. Also included are step-by-step accounts of the two main classes of experimental design: the pre-equilibration ACE (in the form of CE-frontal analysis (CE-FA)) and mobility shift ACE together with examples of their use. The ACE approaches for binding assays of proteins should be considered when the biological material is scarce, when any kind of labeling is not possible or desired, when the interacting molecules are the same size and when rapid and simple method development is a priority.
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14
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Lassen KS, Bradbury ARM, Rehfeld JF, Heegaard NHH. Microscale characterization of the binding specificity and affinity of a monoclonal antisulfotyrosyl IgG antibody. Electrophoresis 2008; 29:2557-64. [PMID: 18494034 DOI: 10.1002/elps.200700908] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Sulfation is a potentially important post-translational modification of proteins and has been demonstrated in a number of polypeptides, notably in gastrointestinal hormones. In contrast to phosphorylation, however, the investigation of sulfation patterns in tissues and on purified proteins has been complicated by the absence of specific immunoreagents (antibodies) for this modification as well as the chemical lability of the sulfate group. Here, we investigate the properties of a novel mAb against sulfated tyrosyl groups (anti-Tyr(SO(3)H) antibody) using CE and a panel of sulfated and nonsulfated peptides and proteins. The data show that the anti-Tyr(SO(3)H) antibody is completely specific for compounds containing sulfated tyrosyls. Affinity electrophoresis experiments allowed us to estimate dissociation constants for sulfated hirudin fragment (56-65), gastrin-17, and cholecystokinin octapeptide (CCK8) in the 1-3 microM range. The affinity of the antibody toward complement 4 protein that contains three sulfotyrosines was analyzed by surface plasmon resonance technology and modeled according to a bivalent-binding model which yielded a K(d1) of 20.1 microM for the monovalent complex. The same binding was studied by CE and found to be in the micromolar scale albeit with some uncertainty due to complex separation patterns. The work illustrates the amount of information on antibody-antigen interactions that may be obtained with microelectrophoretic methods consuming minute quantities of material. Furthermore the specificity of this antibody could be confirmed in one operation using an array of sulfated and nonsulfated compounds.
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Affiliation(s)
- Klaus S Lassen
- Department of Autoimmunology and Immunological Development, Statens Serum Institut, Copenhagen S, Denmark
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15
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Buhl A, Metzger JH, Heegaard NHH, von Landenberg P, Fleck M, Luppa PB. Novel biosensor-based analytic device for the detection of anti-double-stranded DNA antibodies. Clin Chem 2006; 53:334-41. [PMID: 17185362 DOI: 10.1373/clinchem.2006.077339] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Patients with systemic lupus erythematosus (SLE) develop a wide variety of serologic manifestations, including double-stranded DNA autoantibodies (anti-dsDNA). The determination of the potentially pathogenic autoantibodies is diagnostically relevant. METHODS We developed a novel surface plasmon resonance (SPR) biosensor chip for studies of dsDNA and anti-dsDNA binding. A synthetic oligonucleotide was coupled to biotinylated human transferrin, hybridized with the complementary antistrand, and ligated with a human recombinant dsDNA fragment 233 bp in length. After surface immobilization of this antigenic construct, diluted sera from SLE patients and healthy donors were analyzed with the resulting SPR biosensor system. RESULTS This SPR biosensor allowed specific detection of anti-dsDNA. In pilot experiments, sera from SLE patients were distinguished from control sera. We also confirmed the specificity of this biosensor by supplementing anti-dsDNA-positive sera with salmon sperm DNA, which blocked the surface binding of anti-dsDNA in a concentration-dependent manner. CONCLUSIONS An SPR biosensor monitors interactions in real time under homogeneous conditions, providing information about binding kinetics and affinities. Its applicability critically depends on the design of the solid-state surface of the sensor chips. Covalently immobilizing dsDNA as the antigen to the surface in a flow-through cell assured maximal stability for multiple serum injections and regeneration cycles. This technique, which adds a new analytic quality to existing methods, may be beneficial in the diagnosis and clinical monitoring of SLE.
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Affiliation(s)
- Alexander Buhl
- Institute of Clinical Chemistry and Pathobiochemistry, Klinikum rechts der Isar der Techni-schen Universität München, München, Germany
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16
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Kim D, Kwak YG, Kang SH. Real-time observation of temperature-dependent protein–protein interactions using real-time dual-color detection system. Anal Chim Acta 2006; 577:163-70. [PMID: 17723667 DOI: 10.1016/j.aca.2006.06.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 06/15/2006] [Accepted: 06/18/2006] [Indexed: 10/24/2022]
Abstract
This study examined the ability of a real-time dual-color detection system to allow direct observations of the kinetics of temperature-dependent protein-protein interaction at a single-molecule level. The primary target protein was an Alexa Fluor 488-labeled actin conjugate, which had been pre-incubated with an unlabeled rabbit anti-actin antibody (IgG). The complementary fluorescent protein was Alexa Fluor 633-labeled goat anti-rabbit IgG antibody, which interacts with the rabbit anti-actin antibody (IgG) bound to the Alexa Fluor 488-labeled actin conjugate. The individual protein molecules labeled with different fluorescent dyes in solution were effectively focused, interacted with the other protein molecules at 500 aM, and detected directly in real-time using the dual-wavelength (lambda(ex)=488 and 635 nm) laser-induced fluorescence detection system. The kinetics of the protein-protein interactions were examined at different temperatures (12-32 degrees C). At concentrations in the aM range, the number of bound complex molecules through the protein-protein interaction decreased gradually with time at a given temperature, and increased with decreasing temperature at a set time. A high concentration (above 500 pM) of the protein sample caused aggregation and nonspecific binding of the protein molecules, even though the protein molecules were not an example of complementary binding. The results demonstrated that the real-time kinetics of a protein-protein interaction could be analyzed effectively at the single-molecule level without any time delay using the real-time dual-color detection system.
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Affiliation(s)
- Daekwang Kim
- Department of Chemistry, Chonbuk National University, Jeonju 561-756, Republic of Korea
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17
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Miao H, Rubakhin SS, Sweedler JV. Confirmation of peak assignments in capillary electrophoresis using immunoprecipitation. Application to D-aspartate measurements in neurons. J Chromatogr A 2005; 1106:56-60. [PMID: 16199049 DOI: 10.1016/j.chroma.2005.09.037] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2005] [Revised: 09/14/2005] [Accepted: 09/16/2005] [Indexed: 10/25/2022]
Abstract
Capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection is a powerful tool for analysis of samples ranging from tissue extracts to single cells. However, accurate peak identification in electropherograms is challenging when complex biological samples are analyzed, as often matching a migration time between an analyte and corresponding standard may be insufficient to confirm the peak's identity. A method which combines single-step immunoprecipitation and CE-LIF analysis for investigation of the chiral amino acids in single cells and small tissue samples is demonstrated. D-Aspartate (D-Asp) has been reported in the central nervous system of the invertebrate neurobiological model Aplysia californica. In order to confirm the identity of D-Asp signal in the complex electropherograms of nerve tissue extracts and individual neurons, anti-D-Asp serum, preincubated with L-Asp conjugate, is added to the sample. This selectively binds the free D-Asp, creating an antibody-antigen complex with a migration time similar to that of antibody alone, but not that of D-Asp. The complete disappearance of the putative D-Asp peak confirms its identity and validates that there are no other detectable analytes co-migrating with D-Asp in the electropherogram.
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Affiliation(s)
- Hai Miao
- Department of Chemistry, University of Illinois, Champaign, School of Chemical Sciences, 600 South Mathews Avenue 63-5, Urbana, IL 61801, USA
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18
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Monoclonal Antibodies. Hybridoma (Larchmt) 2005. [DOI: 10.1089/hyb.2005.24.211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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19
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Tseng WL, Chang HT, Hsu SM, Chen RJ, Lin S. Immunoaffinity capillary electrophoresis: determination of binding constant and stoichiometry for antibody-antigen interaction. Electrophoresis 2002; 23:836-46. [PMID: 11920868 DOI: 10.1002/1522-2683(200203)23:6<836::aid-elps836>3.0.co;2-j] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Affinity capillary electrophoresis (ACE) can provide both qualitative and quantitative information on molecular interactions and affords the advantages of very low sample consumption, high mass sensitivity, short analysis time, and the use of automated instrumentation. It has been applied clinically and biochemically to the determination of the binding constant and to the measurement of the binding stoichiometry for interactions between antibodies (Ab's) and antigens (Ag's) in free solution. In many situations, the Ag molecule has two or multiple binding sites, each of which has a similar or different intrinsic affinity for binding independently to the combining site(s) on an Ab molecule. The multivalent binding reactions between Ab and Ag molecules often occur. The objective of this review is to describe the uses of ACE in the determination of binding constants and stoichiometry of Ab-Ag interactions (immunoaffnity capillary electrophoresis), focusing especially on multivalent Ab-Ag interaction modes. Five model binding systems developed recently using ACE techniques are described with principles and examples: (i) divalent mAb-monovalent Ag interaction, (ii) divalent mAb-(homo)polyvalent Ag interaction, (iii) cooperativity of two binding sites of mAb-monovalent Ag interaction, (iv) monovalent Fab-divalent Ag interaction, and (v) polyclonal Ab-monovalent Ag interaction. Finally, the determination of binding stoichiometry of Ab-Ag interactions by ACE is described.
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Affiliation(s)
- Wei-Lung Tseng
- Department of Chemistry, National Taiwan University/College of Medicine, 1-1 Jen-ai Road, Taipei, Taiwan, ROC
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20
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Progent F, Taverna M, Le Potier I, Gopée F, Ferrier D. A study of the binding between polymers and peptides, using affinity capillary electrophoresis, applied to polymeric drug delivery systems. Electrophoresis 2002; 23:938-44. [PMID: 11920880 DOI: 10.1002/1522-2683(200203)23:6<938::aid-elps938>3.0.co;2-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We have investigated the potential of affinity capillary electrophoresis (ACE) to evaluate binding constants between an anionic polydispersed polymer and four peptides. Nonlinear regression and three current linearization methods, the y-reciprocal, the x-reciprocal and the double-reciprocal, were employed for the estimation of the binding constants. The x-reciprocal and the double-reciprocal plots indicated the presence of two portions of straight lines for angiopeptin, triptorelin and the thyrotropin releasing hormone (TRH), and therefore the probable existence of a second-order interaction which causes the deviation from the 1:1 model. Peptide 1 exhibited a unique binding constant of 2.4 x 10(6)M(-1). In contrast, angiopeptin, triptorelin and TRH exhibited a K(1) of 4.0 x 10(6), 5.3 x 10(6) and 20.2 x 10(6)M(-1), respectively, and a K(2) of 0.4 x 10(6), 0.5 x 10(6) and 1.4 x 10(6)M(-1), respectively. The origin of the high scattering of the data points was further investigated. Neither the viscosity, nor the adsorption of the peptides to the capillary wall appeared to be the determining factor of data scattering. Finally, a possible adsorption of the polymer leading to the electroosmotic flow instability was supposed.
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Affiliation(s)
- Frédéric Progent
- Groupe de Chimie Analytique de Paris Sud, Faculté de Pharmacie de Paris XI, rue J. B. Clement, F-92290 Châtenay-Malabry, France
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21
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Heegaard NHH, Kennedy RT. Antigen-antibody interactions in capillary electrophoresis. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 768:93-103. [PMID: 11939562 DOI: 10.1016/s0378-4347(01)00489-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Immunoreactions in combination with separations by capillary electrophoresis (CE) are increasingly being used to quantitate specific analytes in biological fluids. Both competitive and non-competitive approaches have been used for the purpose and, in selected cases, now compare favorably with conventional quantitative immunoassays with respect to concentration limits of detection. CE is also a useful method to evaluate antigen-antibody binding on-line and offers unique possibilities for binding constant estimates, also for weakly binding antibodies and antibody fragments. In this review we cover recent developments in the use of antigen-antibody interactions in conjunction with CE and conclude that continued development of miniaturization, on-line preconcentration and more sensitive detection schemes will contribute to the further dissemination of CE-based immunoassays building on already established affinity CE approaches.
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Affiliation(s)
- Niels H H Heegaard
- Department of Autoimmunology, Statens Serum Institute, Copenhagen, Denmark.
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22
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Heegaard NH, Sen JW, Nissen MH. Congophilicity (Congo red affinity) of different beta2-microglobulin conformations characterized by dye affinity capillary electrophoresis. J Chromatogr A 2000; 894:319-27. [PMID: 11100875 DOI: 10.1016/s0021-9673(00)00579-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The amyloidogenic protein beta-microglobulin was characterized by affinity capillary electrophoresis (CE). CE could separate conformational variants of beta2-microglobulin and with the amyloid-specific dye Congo red as a buffer additive it was possible to measure different Congo red-affinities of native and abnormally folded beta2-microglobulin. We find that native beta2-microglobulin has an intermediate affinity for Congo red at pH 7.3 and that binding involves electrostatic interactions. The conformational variant of beta2-microglobulin that appears in acetonitrile solutions binds Congo red more strongly. Affinity CE using Congo red as a buffer additive is a new, simple, fast, and quantitative micromethod for the characterization of soluble conformational intermediates of amyloidogenic proteins.
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Affiliation(s)
- N H Heegaard
- Department of Autoimmunology, Statens Serum Institut, Copenhagen, Denmark.
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23
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Abstract
Molecular recognition may be characterized both qualitatively and quantitatively by electrophoretic methods if complexed molecules differ in electrophoretic mobility from unbound ones. The use of capillary zone electrophoresis (CE) for the characterization of affinity interactions is advantageous because of the high resolution, reproducibility and wide applicability of the technique and because of the mild conditions, i.e., physiological buffers without additions of organics or detergents, that are often sufficient for highly efficient separations. CE gives the ability to characterize binding between small amounts of unlabelled reactants in solution, has few requirements for special characteristics of the interacting molecules and is also applicable to the study of interactions of individual components in mixtures, as detection of binding and analytical separation are achieved in one step. This is unique compared with other techniques for the study of non-covalent interactions. The advantages and disadvantages of using CE to demonstrate molecular interactions, to screen for specific ligand binding in complex mixtures and to calculate binding constants will be discussed.
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Affiliation(s)
- N H Heegaard
- Department of Autoimmunology, Statens Serum Institut, Copenhagen, Denmark.
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24
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Koizumi A, Morita T, Murakami Y, Morita Y, Sakaguchi T, Yokoyama K, Tamiya E. Enzyme immunoassay by capillary electrophoresis with laser induced fluorescence detection. Anal Chim Acta 1999. [DOI: 10.1016/s0003-2670(99)00576-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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25
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Heegaard NH, Kennedy RT. Identification, quantitation, and characterization of biomolecules by capillary electrophoretic analysis of binding interactions. Electrophoresis 1999; 20:3122-33. [PMID: 10596820 DOI: 10.1002/(sici)1522-2683(19991001)20:15/16<3122::aid-elps3122>3.0.co;2-m] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The high resolving power of capillary electrophoresis combined with the specificity of binding interactions may be used with advantage to characterize the structure-function relationship of biomolecules, to quantitate specific analytes in complex sample matrices, and to determine the purity of pharmaceutical and other molecules. We here review recent and innovative methodologies and applications of high resolution affinity electrophoresis within the fields of binding constant determination, structure-activity studies, quantitative microassays, analysis of drug purity and protein conformation, and immobilized affinity ligands. Despite the virtues of these approaches with respect to applicability, resolving power, speed, and low sample consumption, problems remain with respect to analyte identification and low concentration limits of detection. The ongoing development of new detector technologies for capillary electrophoresis such as mass spectrometry, and possibly nuclear magnetic resonance and other spectroscopic methods, is therefore very promising for the continued increased use of affinity capillary electrophoresis.
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Affiliation(s)
- N H Heegaard
- Department of Autoimmunology, Statens Serum Institut, Copenhagen, Denmark.
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26
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Capillary electrophoretic determination of the association constant of a protein and a neutral carbohydrate by introducing mercaptoethanesulfonate tags to the carbohydrate. J Chromatogr A 1999. [DOI: 10.1016/s0021-9673(99)00095-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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27
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Taga A, Uegaki K, Yabusako Y, Kitano A, Honda S. Simultaneous determination of the association constants of oligosaccharides to a lectin by capillary electrophoresis. J Chromatogr A 1999. [DOI: 10.1016/s0021-9673(99)00104-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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28
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Heegaard NH, Nilsson S, Guzman NA. Affinity capillary electrophoresis: important application areas and some recent developments. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1998; 715:29-54. [PMID: 9792496 DOI: 10.1016/s0378-4347(98)00258-8] [Citation(s) in RCA: 156] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Affinity capillary electrophoresis (ACE) is a broad term referring to the separation by capillary electrophoresis of substances that participate in specific or non-specific affinity interactions during electrophoresis. The interacting molecules can be found free in solution or can be immobilized to a solid support. Every ACE mode has advantages and disadvantages. Each can be used for a wide variety of applications. This paper focuses on applications that include purification and concentration of analytes present in diluted solutions or complex matrices, quantitation of analytes based on calibration curves, and estimation of binding constants from direct and derived binding curves based on quantitation of analytes or on analyte migration shifts. A more recent chemicoaffinity strategy in capillary electrophoresis/capillary electrochromatography (CE/CEC) termed molecular imprinting ('plastic antibodies') is discussed as well. Although most ACE studies are aimed at characterizing small-molecular mass analytes such as drugs, hormones, and peptides, some efforts have been pursued to characterize larger biopolymers including proteins, such as immunoglobulins. Examples of affinity interactions that have been studied are antigen-antibody, hapten-antibody, lectin-sugar, drug-protein, and enzyme-substrate complexes using ultraviolet, laser-induced fluorescence, and mass spectrometer detectors. This paper also addresses the critical issue of background electrolyte selection and quantitation of analytes. Specific examples of bioaffinity applications are presented, and the future of ACE in the biomedical field is discussed.
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Affiliation(s)
- N H Heegaard
- Department of Autoimmunology, Statens Serum Institut, Copenhagen, Denmark
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30
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Kajiwara H. Motif 2 in adenosine kinase homologous ginseng polypeptide showed affinity to D-ribose by capillary zone electrophoresis and surface plasmon resonance. J Chromatogr A 1998; 817:173-9. [PMID: 9764491 DOI: 10.1016/s0021-9673(98)00244-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Affinity capillary electrophoresis (ACE) and surface plasmon resonance (SPR) were applied to the analysis of anti-lipolytic acidic tetradecapeptide from Panax ginseng roots. The ginseng polypeptide (GPP) and modified GPPs were chemically synthesized and their affinity to D-ribose and adenosine was examined by ACE and SPR. GPP had affinity to D-ribose and adenosine and the binding constants (Kb) to GPP were calculated by both methods (Kb = 1.04 x 10(4) mol-1 to D-ribose by ACE and Kb = 1.91 x 10(4) mol-1 to adenosine by SPR). Most of the modified GPPs lost their affinity to D-ribose and adenosine through substitution or rearrangement of the amino acids.
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Affiliation(s)
- H Kajiwara
- National Institute of Agrobiological Resources, Ibaraki, Japan
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31
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Quantitative relationship between retention in HPLC and CE via binding constants and selector concentrations. Trends Analyt Chem 1998. [DOI: 10.1016/s0165-9936(97)00120-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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32
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Qian XH, Tomer KB. Affinity capillary electrophoresis investigation of an epitope on human immunodeficiency virus recognized by a monoclonal antibody. Electrophoresis 1998; 19:415-9. [PMID: 9551794 DOI: 10.1002/elps.1150190309] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Affinity capillary electrophoresis (ACE) has been used to investigate the epitope on the human immunodeficiency virus (HIV) core protein p24 recognized by the monoclonal antibody (mAb) 13-102-100. The affinity of a series of peptides with N- and C-terminal truncations of the epitope sequence determined by mass spectrometry was studied. The peak area change assay was used for the study of the interactions of the mAb with those peptides, exhibiting tight binding to the mAb, and the migration time shift assay was used to probe the relative affinities of peptides showing weak binding to the mAb. The experimental results show that the monoclonal antibody 13-102-100 recognizes the peptide VHPVHAGPIAP with highest affinity. Smaller peptides incorporating only part of the epitope, however, are recognized to some extent in the ACE experiments.
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Affiliation(s)
- X H Qian
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
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33
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Abstract
The application of affinity capillary electrophoresis (ACE) to the study of molecular interactions is reviewed. ACE appears to be a sensitive, versatile and convenient tool to obtain reliable data on binding constants and stoichiometries of interacting systems using the Hummel-Dreyer method and variants thereof. A powerful feature is the possibility to analyze simultaneously the affinity of a large number of compounds for the same ligand, making it a promising tool for the screening of large combinatorial libraries.
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Affiliation(s)
- G Rippel
- Delft University of Technology, Department of Biochemical Engineering, The Netherlands
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34
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Abstract
This review article with 237 references is focused on capillary zone electrophoresis (CZE) of proteins. It includes discussion of modeling electrophoretic migration of proteins, sample pretreatment before the analysis, methods reducing the sorptions of proteins on the capillary wall, and techniques for increasing selectivity by using electrolyte additives including the sieving matrices. Significant progress in detection techniques, namely in laser-induced fluorescence and mass spectrometry, is emphasized. Modifications of CZE using specific interactions, such as affinity capillary electrophoresis or capillary immunoelectrophoresis, are debated as well as combination of CZE with other separation methods such as high performance liquid chromatography (HPLC). A number of practical applications of CZE of proteins are described.
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Affiliation(s)
- V Dolnik
- Molecular Dynamics, Sunnyvale, CA 94086, USA.
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35
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Shimura K, Kasai K. Affinity capillary electrophoresis: a sensitive tool for the study of molecular interactions and its use in microscale analyses. Anal Biochem 1997; 251:1-16. [PMID: 9300076 DOI: 10.1006/abio.1997.2212] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- K Shimura
- Department of Biological Chemistry, Faculty of Pharmaceutical Sciences, Teikyo University, Kanagawa, Japan.
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36
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Heegaard NH, Brimnes J. Comparison of heparin-binding to lactoferrin from human milk and from human granulocytes by means of affinity capillary electrophoresis. Electrophoresis 1996; 17:1916-20. [PMID: 9034775 DOI: 10.1002/elps.1150171218] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Human lactoferrin from two different sources: milk and secondary granules of neutrophil granulocytes, was compared with respect to heparin binding by means of affinity capillary electrophoresis. This method is based on analysis of migration pattern shifts induced by various amounts of ligand present in the electrophoresis buffer. Since lactoferrin is a basic molecule, analyses were performed at pH 8 in a capillary with a neutral hydrophilic coating. However, analyzable peaks were only obtained in the presence of heparin in the electrophoresis buffer. Proportionally to the amount of heparin present, these peaks exhibited shape changes and strong migration shifts. In the ensuing analysis it could be demonstrated that the two lactoferrins had comparable migration shifts and peak shape changes. This indicates that also in this respect the two forms of lactoferrin are identical. Affinity capillary electrophoresis is a convenient and fast method to investigate functional characteristics of low amounts of unmodified biomolecules.
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Affiliation(s)
- N H Heegaard
- Department of Autoimmunology, Statens Serum Institute, Copenhagen, Denmark.
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