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Warryn L, Dangy JP, Gersbach P, Gehringer M, Altmann KH, Pluschke G. An Antigen Capture Assay for the Detection of Mycolactone, the Polyketide Toxin of Mycobacterium ulcerans. THE JOURNAL OF IMMUNOLOGY 2021; 206:2753-2762. [PMID: 34031146 DOI: 10.4049/jimmunol.2001232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/29/2021] [Indexed: 11/19/2022]
Abstract
Mycolactone is a cytotoxin responsible for most of the chronic necrotizing pathology of Mycobacterium ulcerans disease (Buruli ulcer). The polyketide toxin consists of a 12-membered lactone ring with a lower O-linked polyunsaturated acyl side chain and an upper C-linked side chain. Mycolactone is unique to M. ulcerans and an immunological Ag capture assay would represent an important tool for the study of Buruli ulcer pathogenesis and for laboratory diagnosis. When testing sets of mycolactone-specific mouse mAbs, we found that Abs against the hydrophobic lower side chain only bind mycolactone immobilized on a solid support but not when present in solution. This observation supports previous findings that mycolactone forms micellar structures in aqueous solution with the hydrophobic region sequestered into the inner core of the aggregates. Although an Ag capture assay typically requires two Abs that recognize nonoverlapping epitopes, our search for matching pairs of mAbs showed that the same mAb could be used both as capture and as detecting reagent for the detection of the mycolactone aggregates. However, the combination of a core-specific and a core/upper side chain-specific mAb constituted the most sensitive ELISA with a sensitivity in the low nanogram range. The results of a pilot experiment showed that the sensitivity of the assay is sufficient to detect mycolactone in swab samples from Buruli ulcer lesions. Although the described capture ELISA can serve as a tool for research on the biology of mycolactone, the assay system will have to be adapted for use as a diagnostic tool.
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Affiliation(s)
- Louisa Warryn
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland; and
| | - Jean-Pierre Dangy
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland; and
| | - Philipp Gersbach
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology Zürich, Zürich, Switzerland
| | - Matthias Gehringer
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology Zürich, Zürich, Switzerland
| | - Karl-Heinz Altmann
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology Zürich, Zürich, Switzerland
| | - Gerd Pluschke
- Swiss Tropical and Public Health Institute, Basel, Switzerland; .,University of Basel, Basel, Switzerland; and
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Korbakis D, Brinc D, Schiza C, Soosaipillai A, Jarvi K, Drabovich AP, Diamandis EP. Immunocapture-Selected Reaction Monitoring Screening Facilitates the Development of ELISA for the Measurement of Native TEX101 in Biological Fluids. Mol Cell Proteomics 2015; 14:1517-26. [PMID: 25813379 DOI: 10.1074/mcp.m114.047571] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Indexed: 11/06/2022] Open
Abstract
Monoclonal antibodies that bind the native conformation of proteins are indispensable reagents for the development of immunoassays, production of therapeutic antibodies and delineating protein interaction networks by affinity purification-mass spectrometry. Antibodies generated against short peptides, protein fragments, or even full length recombinant proteins may not bind the native protein form in biological fluids, thus limiting their utility. Here, we report the application of immunocapture coupled with selected reaction monitoring measurements (immunocapture-SRM), in the rapid screening of hybridoma culture supernatants for monoclonal antibodies that bind the native protein conformation. We produced mouse monoclonal antibodies, which detect in human serum or seminal plasma the native form of the human testis-expressed sequence 101 (TEX101) protein-a recently proposed biomarker of male infertility. Pairing of two monoclonal antibodies against unique TEX101 epitopes led to the development of an ELISA for the measurement of TEX101 in seminal plasma (limit of detection: 20 pg/ml) and serum (limit of detection: 40 pg/ml). Measurements of matched seminal plasma samples, obtained from men pre- and post-vasectomy, confirmed the absolute diagnostic specificity and sensitivity of TEX101 for noninvasive identification of physical obstructions in the male reproductive tract. Measurement of male and female serum samples revealed undetectable levels of TEX101 in the systemic circulation of healthy individuals. Immunocapture-SRM screening may facilitate development of monoclonal antibodies and immunoassays against native forms of challenging protein targets.
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Affiliation(s)
- Dimitrios Korbakis
- From the ‡Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; §Department of Clinical Biochemistry, University Health Network, Toronto, Canada
| | - Davor Brinc
- ¶Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Canada
| | - Christina Schiza
- From the ‡Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; ¶Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Canada
| | | | - Keith Jarvi
- ‖Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada; **Department of Surgery, Division of Urology, Mount Sinai Hospital, University of Toronto, Canada
| | - Andrei P Drabovich
- From the ‡Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; §Department of Clinical Biochemistry, University Health Network, Toronto, Canada;
| | - Eleftherios P Diamandis
- From the ‡Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; §Department of Clinical Biochemistry, University Health Network, Toronto, Canada; ¶Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Canada; ‖Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada;
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Addressing matrix effects in ligand-binding assays through the use of new reagents and technology. Bioanalysis 2014; 6:1059-67. [DOI: 10.4155/bio.14.75] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Background: Ligand-binding assays (LBAs) used in the quantification of biotherapeutics for pharmacokinetic determinations rely on interactions between reagents (antibodies or target molecule) and the biotherapeutic. Most LBAs do not employ an analyte extraction procedure and are susceptible to matrix interference. Here, we present a case study on the development of a LBA for the quantification of a PEGylated domain antibody where matrix interference was observed. The assay used to support the single ascending dose study was a plate-based electrochemiluminescent assay with a lower limit of quantification of 80 ng/mL. To meet sensitivity requirements of future studies, new reagents and the Gyrolab™ Workstation were evaluated. Results: Assay sensitivity improved nearly threefold in the final method utilizing new antibody reagents, a buffer containing blockers to human anti-animal antibodies, and the Gyrolab Workstation. Conclusion: Experimental data indicate that all factors changed played a role in overcoming matrix effects.
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Joyce AP, Leung SS. Use of response surface methods and path of steepest ascent to optimize ligand-binding assay sensitivity. J Immunol Methods 2013; 392:12-23. [PMID: 23500784 DOI: 10.1016/j.jim.2013.02.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 02/06/2013] [Accepted: 02/27/2013] [Indexed: 11/15/2022]
Abstract
Response surface methods (RSM) combined with a steepest ascent approach is a powerful technique to optimize assay performance. In this case, a ligand-binding assay (LBA) to quantitate a peptide biotherapeutic was optimized for improved sensitivity using this technique. Conditions were elucidated to enable pg/mL quantitation of the peptide in human plasma using steepest ascent to efficiently optimize assay factors. Instead of relying solely on assay development experience and intuition to improve assay sensitivity, this systematic approach takes advantage of a predictive mathematical model generated through response surface methods that defines a specific path towards greater predicted assay sensitivity. The actual response observed along the steepest ascent path was in good agreement with the model for several steps, until reagent concentrations moved beyond the physical limits of the system, and model breakdown occurred. RSM combined with steepest ascent method proved a useful tool for sensitivity optimization in three ways: (1) The required LBA sensitivity performance (approximately 200 pg/mL), measured as a signal-to-noise ratio (SNR) at the targeted lower limit of quantitation (LLOQ), was efficiently achieved in only two optimization experiments; (2) Steepest ascent confirmed that the desired sensitivity was found within the initial RSM design space, and no further gain in sensitivity was found venturing beyond this design space along the steepest ascent path; (3) The desired assay sensitivity was maintained over a reasonable range of reagent concentrations along the steepest ascent path, indicating assay robustness for this parameter.
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Shi X, Song S, Sun A, Li D, Wu A, Zhang D. Determination of Chloramphenicol Residues in Foods by ELISA and LC-MS/MS Coupled with Molecularly Imprinted Solid Phase Extraction. ANAL LETT 2010. [DOI: 10.1080/00032711003763616] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Doucet J, Avrameas A. A novel method for quantitative measurement of a therapeutic monoclonal antibody in the presence of its target protein using enzymatic digestion. J Pharm Biomed Anal 2010; 52:565-70. [DOI: 10.1016/j.jpba.2010.01.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 01/14/2010] [Accepted: 01/17/2010] [Indexed: 10/19/2022]
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