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Yang C, Yan B. Dual-Function Platform Based on Postsynthetic Functionalization of a Water-Stable Hydrogen-Bonded Organic Framework: Ratiometric Sensing of Nicotine and Cotinine and Dynamic Anticounterfeiting for Information Encryption. Inorg Chem 2023; 62:20458-20466. [PMID: 38032229 DOI: 10.1021/acs.inorgchem.3c03478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Nicotine and its major metabolite cotinine are widely used as markers of tobacco smoke abstinence as well as indicators of active smoking levels and the assessment of passive inhalation of tobacco smoke in nonsmokers. Therefore, using an easy-to-prepare sensing platform that can provide a rapid, highly sensitive response for the simultaneous detection of salivary nicotine levels and urinary cotinine levels is especially crucial for helping heavy cigarette smokers quit smoking and protecting public health. Hydrogen-bonded organic frameworks, as a novel class of porous crystalline materials, show immense potential for functional modification and optical sensing. Herein, a new HOF was prepared by a simple solvent evaporation method, and a dual-emitting material Eu(bpy)@HOF-215(1) was obtained by the postsynthetic modification of HOF by lanthanide luminescent complexes, which maintains favorable structural stability and introduces the characteristic emitting of Eu, allowing use as a ratiometric fluorescent sensor for salivary nicotine and urinary cotinine, with a limit of detection of nicotine of 0.045 μM in saliva and a limit of detection of cotinine of 0.591 μM in urine. Furthermore, luminescent inks based on HOF-215 have been fabricated based on the photoresponse variations of 1 to NIC and COT, which enables the multilevel encryption and decryption of information, in a dynamic and recyclable process. This work not only synthesizes a novel blue HOF but also provides a representative successful case of a dual-function platform for simultaneous application to ratiometric sensing and dynamic anticounterfeiting.
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Affiliation(s)
- Chunyu Yang
- Shanghai Key Laboratory of Chemical Assessment and Sustainability, School of Chemical Science and Engineering, Tongji University, Siping Road 1239, Shanghai 200092, China
| | - Bing Yan
- Shanghai Key Laboratory of Chemical Assessment and Sustainability, School of Chemical Science and Engineering, Tongji University, Siping Road 1239, Shanghai 200092, China
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2
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Kiguchi Y, Morita I, Yamaki K, Takegami S, Kobayashi N. Framework-Directed Amino-Acid Insertions Generated over 55-Fold Affinity-Matured Antibody Fragments That Enabled Sensitive Luminescent Immunoassays of Cortisol. Biol Pharm Bull 2023; 46:1661-1665. [PMID: 38044090 DOI: 10.1248/bpb.b23-00656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
We generated three single-chain Fv fragments (scFvs) specific to cortisol according to our original affinity-maturation strategy and verified their utility in developing immunoassays. These scFv mutants (m-scFvs) had insertion of one, four, or six amino acid(s) in the framework region 1 of the VH-domain and showed >55-fold higher affinity (Ka, 2.0 - 2.2 × 1010 M-1) than the unmodified scFv (wt-scFv). Each m-scFv was fused with NanoLuc luciferase (NLuc) for the use in enzyme-linked immunosorbent assays (ELISAs). In these ELISA, the m-scFv-NLuc fusions were competitively reacted with immobilized cortisol residues and cortisol standards, and then the bound NLuc activity was monitored luminometrically. The luminescent ELISAs generated dose-response curves with extremely low midpoints (approx. 3 pg/assay) and were >150-fold more sensitive than the colorimetric ELISAs using wt-scFv and >8000-fold more sensitive than the ELISA using the parental native antibody. The luminescent ELISAs showed acceptable cross-reactivity patterns with related steroids, and the determination of control sera afforded cortisol levels in the reference range with satisfactory parallelism.
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Affiliation(s)
- Yuki Kiguchi
- Kobe Pharmaceutical University
- Kyoto Pharmaceutical University
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3
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Kiguchi Y. A Novel System for Discovering High-affinity Antibody Mutants That Enables Immunoassays with Higher Sensitivities —Development and Application of Clonal Array Profiling (CAP)—. YAKUGAKU ZASSHI 2022; 142:1153-1159. [DOI: 10.1248/yakushi.22-00141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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4
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Kiguchi Y, Morita I, Tsuruno A, Kobayashi N. Retrieving Dissociation-Resistant Antibody Mutants: An Efficient Strategy for Developing Immunoassays with Improved Sensitivities. Biol Pharm Bull 2022; 45:1432-1437. [PMID: 36184500 DOI: 10.1248/bpb.b22-00454] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previously, we generated high-affinity antibody mutants that enabled sensitive immunoassays by exploring diverse libraries of single-chain Fv fragments (scFvs) displayed on bacteriophage. To isolate rarely-occurring desirable clones, "panning" has commonly been performed but is often unsuccessful. Therefore, we previously developed a clonal array profiling (CAP) method, wherein scFv-displaying phage (scFv-Ph) clones in a library were examined individually regarding their ability to target antigens immobilized on microwells. Clones that showed strong reactivity were recovered via dissociation using an acidic treatment. The CAP successfully discovered cortisol-specific scFvs showing 17-31-fold improved Ka from libraries generated via site-directed insertions in a prototype anti-cortisol scFv (wt-scFv; Ka, 3.6 × 108 M-1), but their Ka did not exceed 1.1 × 1010 M-1. In this study, to break this possible affinity ceiling, we devised a new system employing a dissociation-independent recovery. scFv-Phs were individually reacted to target antigen (cortisol) immobilized on microwells via a linker containing a disulfide bond. Following acidic and basic treatments to eliminate scFv-Phs with "ordinary affinities," dissociation-resistant scFv-Phs remaining on the microwells were retrieved via reductive cleavage of the disulfide bonds. This system allowed for a straightforward and efficient discovery of scFv mutants with 33-56-fold increased Ka (1.2-2.0 × 1010 M-1), exceeding the previous affinity ceiling. These scFvs enabled an enzyme-linked immunosorbent assay for cortisol with 18-51-fold higher sensitivity than the assay performed using wt-scFv.
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5
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Li L, Wu S, Si Y, Li H, Yin X, Peng D. Single-chain fragment variable produced by phage display technology: Construction, selection, mutation, expression, and recent applications in food safety. Compr Rev Food Sci Food Saf 2022; 21:4354-4377. [PMID: 35904244 DOI: 10.1111/1541-4337.13018] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 07/06/2022] [Accepted: 07/08/2022] [Indexed: 01/28/2023]
Abstract
Immunoassays are reliable, efficient, and accurate methods for the analysis of small-molecule harmful substances (such as pesticides, veterinary drugs, and biological toxins) that may be present in food. However, traditional polyclonal and monoclonal antibodies are limited by animal hosts and hinder further development of immunoassays. With the gradual application of phage display technology as an efficient in vitro selection technology, the single-chain fragment variable (scFv) now provides an exciting alternative to traditional antibodies. Efficiently constructed scFv source libraries and specifically designed biopanning schemes can now yield scFvs possessing specific recognition capabilities. A rational mutation strategy further enhances the affinity of scFv, and allows it to reach a level that cannot be achieved by immunization. Finally, appropriate prokaryotic expression measures ensure stable and efficient production of scFv. Therefore, when developing excellent scFvs, it is necessary to focus on three key aspects of this process that include screening, mutation, and expression. In this review, we analyze in detail the preparation and affinity improvement process for scFv and provide insights into the research progress and development trend of scFv-based immunoassay methods for monitoring small-molecule harmful substances.
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Affiliation(s)
- Long Li
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MOA Key Laboratory for the Detection of Veterinary Drug Residues in Foods, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Shuangmin Wu
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MOA Key Laboratory for the Detection of Veterinary Drug Residues in Foods, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yu Si
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MOA Key Laboratory for the Detection of Veterinary Drug Residues in Foods, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Huaming Li
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MOA Key Laboratory for the Detection of Veterinary Drug Residues in Foods, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xiaoyang Yin
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MOA Key Laboratory for the Detection of Veterinary Drug Residues in Foods, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Dapeng Peng
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MOA Key Laboratory for the Detection of Veterinary Drug Residues in Foods, Huazhong Agricultural University, Wuhan, Hubei, China.,Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Shenzhen, Guangdong, China.,Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong, China.,Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong, China
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6
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Morita I, Kiguchi Y, Oyama H, Yamaki K, Sakio N, Kashiwabara K, Kuroda Y, Ito A, Yokota A, Ikeda N, Kikura-Hanajiri R, Ueda H, Numazawa S, Yoshida T, Kobayashi N. Derivatization-assisted immunoassays: application for group-specific detection of potent methamphetamine and amphetamine enantiomers. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2022; 14:2745-2753. [PMID: 35785801 DOI: 10.1039/d2ay00940d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Reliable and feasible tools for detecting (S)-methamphetamine [(S)-MAP] and (S)-amphetamine [(S)-AP] are required for regulating their illicit circulation. Antibodies that react equally to these stimulants are desirable for this purpose, but have been difficult to generate because of the crucial difference between their characteristic structures: i.e., N-methylamino (MAP) and amino (AP) groups. Furthermore, their small molecular masses (Mr < 150) have hampered the generation of high-affinity antibodies. To overcome these problems, we converted (S)-MAP and -AP into their 2-(trimethylsilyl)ethyl carbamate forms, Teoc-(S)-MAP and -AP, respectively, as surrogate analytes. The Teoc-derivatization not only increases their molecular masses, but also masks their structural differences. We generated a novel monoclonal antibody that showed a satisfactory affinity to Teoc-(S)-MAP residues (Kd = 13 nM as the IgG form) and developed a competitive enzyme-linked immunosorbent assay (ELISA) using microplates containing immobilized Teoc-(S)-MAP residues. Almost overlapping dose-response curves were obtained for Teoc-(S)-MAP and -AP, with the limit of detection of 0.078 and 0.10 ng per assay, respectively. A fixed amount of test powder sample (1 mg) was derivatized with Teoc-O-succinimidyl for 5 min, and subjected to ELISA using Teoc-(S)-MAP as the calibration standard. Under this protocol, (S)-MAP and -AP were converted to their Teoc derivatives with 30% and 34% yield, respectively, determined using ELISA as "Teoc-(S)-MAP equivalent," being distinguished from the derivatization products of (R)-MAP, (R)-AP, ephedrine, (S)-methylenedioxymethamphetamine, tyramine, dopamine, and β-alanine. This ELISA detected as little as 10 μg of (S)-MAP and -AP, and (S)-MAP in urine obtained from (S)-MAP-administered rats. Immunochromatography devices were also developed using gold nanoparticles coated with the monoclonal antibody, with which 0.10 mg of (S)-MAP and -AP was detected by the naked eye. We conclude that the present derivatization-assisted immunoassays may be useful for the detection of (S)-MAP and/or -AP in early stage screening of suspicious substances.
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Affiliation(s)
- Izumi Morita
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Yuki Kiguchi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Hiroyuki Oyama
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Kouya Yamaki
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Nami Sakio
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Keisuke Kashiwabara
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Yumi Kuroda
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Aya Ito
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Asaka Yokota
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Natsumi Ikeda
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Ruri Kikura-Hanajiri
- National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki 210-9501, Japan
| | - Hiroshi Ueda
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan
| | - Satoshi Numazawa
- Department of Pharmacology, Toxicology, and Therapeutics, Showa University School of Pharmacy, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Takemi Yoshida
- Department of Pharmacology, Toxicology, and Therapeutics, Showa University School of Pharmacy, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
- Council on Pharmacists Credentials, 1-9-2 Nishi-shinbashi, Minato-ku, Tokyo 105-0003, Japan
| | - Norihiro Kobayashi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
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7
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Jin S, Pang W, Zhao L, Zhao Z, Mei S. Review of HPLC-MS methods for the analysis of nicotine and its active metabolite cotinine in various biological matrices. Biomed Chromatogr 2022; 36:e5351. [PMID: 35106788 DOI: 10.1002/bmc.5351] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 11/23/2021] [Accepted: 12/20/2021] [Indexed: 11/11/2022]
Abstract
In recent years, tobacco smoking is a risk factor for a series of diseases including cardiovascular diseases, cerebrovascular diseases, and cancers. Nicotine, the primary component of tobacco smoke, is mainly transformed to its active metabolite cotinine, which is often used as biomarker for tobacco exposure for its higher blood concentration and longer residence time than nicotine. Various analytical methods have been developed for the determination of nicotine and cotinine in biological matrices. This article reviewed the HPLC-MS based methods for nicotine and/or cotinine analysis in various biological matrices. The sample preparation, mass and chromatographic conditions and method validation results of these methods have been summarized and analyzed. Sample was mainly pretreated by protein precipitation and/or extraction. Separation was achieved using methanol and/or acetonitrile:water (with or without ammonium acetate) on C18 columns, and acetonitrile:water (with formic acid, ammonium acetate/formate) on HILIC columns. Nicotine-d3, nicotine-d4 and cotinine-d3 were commonly used internal standards. Other non-deuterated IS were also used such as ritonavir, N-ethylnorcotinine, and milrinone. For both nicotine and cotinine, the calibration range was 0.005-35000 ng/mL, the matrix effect was 75.96% - 126.8% and the recovery was 53% - 124.5%. The two analytes were stable at room temperature for 1-10 days, at -80 °C for up to 6 months, and after 3-6 freeze-thaw cycles. Comedications did not affect nicotine and cotinine analysis.
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Affiliation(s)
- Siyao Jin
- Clinical Research Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, P. R. China.,Department of Clinical Pharmacology, College of Pharmaceutical Sciences, Capital Medical University, Beijing, P. R. China
| | - Wenyuan Pang
- Department of Clinical Pharmacology, College of Pharmaceutical Sciences, Capital Medical University, Beijing, P. R. China.,Department of Pharmacy, Beijing Tiantan Hospital, Capital Medical University, Beijing, P. R. China
| | - Libo Zhao
- Clinical Research Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, P. R. China.,Department of Clinical Pharmacology, College of Pharmaceutical Sciences, Capital Medical University, Beijing, P. R. China
| | - Zhigang Zhao
- Department of Clinical Pharmacology, College of Pharmaceutical Sciences, Capital Medical University, Beijing, P. R. China
| | - Shenghui Mei
- Department of Clinical Pharmacology, College of Pharmaceutical Sciences, Capital Medical University, Beijing, P. R. China
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8
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Morita I, Kiguchi Y, Oyama H, Takeuchi A, Tode C, Tanaka R, Ogata J, Kikura-Hanajiri R, Kobayashi N. Derivatization-assisted enzyme-linked immunosorbent assay for identifying hallucinogenic mushrooms with enhanced sensitivity. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2021; 13:3954-3962. [PMID: 34528944 DOI: 10.1039/d1ay01157j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
A sensitive immunochemical method for identifying hallucinogenic mushrooms (magic mushrooms) is required for regulating their illicit use. We have previously generated a monoclonal antibody (mAb) that targets psilocin (Psi), the major psychoactive compound in hallucinogenic mushrooms, and developed an enzyme-linked immunosorbent assay (ELISA). However, this ELISA failed to achieve the expected low-picomole-range sensitivity, as a result of insufficient affinity of the mAb to Psi. It is recognized that haptenic antigens with a larger molecular mass tend to induce antibodies with higher affinities. Thus, we herein report a "derivatization-assisted ELISA," in which the "real analyte" Psi was determined as a "surrogate analyte," the tert-butyldimethylsilyl ether analog thereof (TBS/Psi) having a 1.6-fold greater molecular mass (Mr 318.53) than Psi. A novel mAb against TBS/Psi, prepared by immunizing mice with a TBS/Psi-albumin conjugate showed a 69-fold higher affinity to TBS/Psi residues (Ka = 3.6 × 107 M-1 as IgG) than that of our previous mAb against Psi. This mAb consequently enabled a competitive ELISA for measuring TBS/Psi with the desired sensitivity: the dose-response curve midpoint (12.1 pmol per assay) was >100-fold lower than that of the previous ELISA for determining Psi. Extracts of dried mushroom powders were mixed with TBS triflate for 30 min at room temperature, converting Psi into TBS/Psi in approximately 50% yield. The reaction mixture was then subjected to an ELISA using the anti-TBS/Psi mAb to determine TBS/Psi. Psilocybe cubensis, a species of hallucinogenic mushrooms, gave rise to positive signals, indicating the presence of Psi therein in the expected quantity, while no detectable response was observed for four kinds of edible mushrooms available in the markets.
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Affiliation(s)
- Izumi Morita
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Yuki Kiguchi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Hiroyuki Oyama
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Atsuko Takeuchi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Chisato Tode
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
| | - Rie Tanaka
- National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki 210-9501, Japan
| | - Jun Ogata
- National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki 210-9501, Japan
| | - Ruri Kikura-Hanajiri
- National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki 210-9501, Japan
| | - Norihiro Kobayashi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
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Kiguchi Y, Oyama H, Morita I, Nagata Y, Umezawa N, Kobayashi N. The V H framework region 1 as a target of efficient mutagenesis for generating a variety of affinity-matured scFv mutants. Sci Rep 2021; 11:8201. [PMID: 33859250 PMCID: PMC8050046 DOI: 10.1038/s41598-021-87501-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 03/30/2021] [Indexed: 11/30/2022] Open
Abstract
In vitro affinity-maturation potentially generates antibody fragments with enhanced antigen-binding affinities that allow for developing more sensitive diagnostic systems and more effective therapeutic agents. Site-directed mutagenesis targeting “hot regions,” i.e., amino acid substitutions therein frequently increase the affinities, is desirable for straightforward discovery of valuable mutants. We here report two “designed” site-directed mutagenesis (A and B) targeted the N-terminal 1–10 positions of the VH framework region 1 that successfully improved an anti-cortisol single-chain Fv fragment (Ka, 3.6 × 108 M−1). Mutagenesis A substituted the amino acids at the position 1–3, 5–7, 9 and 10 with a limited set of substitutions to generate only 1,536 different members, while mutagenesis B inserted 1–6 random residues between the positions 6 and 7. Screening the resulting bacterial libraries as scFv-phage clones with a clonal array profiling system provided 21 genetically unique scFv mutants showing 17–31-fold increased affinity with > 109 M−1Ka values. Among the mutants selected from the library A and B, scFv mA#18 (with five-residue substitutions) and mB1-3#130 (with a single residue insertion) showed the greatest Ka value, 1.1 × 1010 M−1.
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Affiliation(s)
- Yuki Kiguchi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Hiroyuki Oyama
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Izumi Morita
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Yasuhiro Nagata
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Naoko Umezawa
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Norihiro Kobayashi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan.
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10
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Morita I, Oyama H, Kiguchi Y, Oguri A, Fujimoto N, Takeuchi A, Tanaka R, Ogata J, Kikura-Hanajiri R, Kobayashi N. Immunochemical monitoring of psilocybin and psilocin to identify hallucinogenic mushrooms. J Pharm Biomed Anal 2020; 190:113485. [PMID: 32866746 DOI: 10.1016/j.jpba.2020.113485] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/12/2020] [Accepted: 07/16/2020] [Indexed: 11/28/2022]
Abstract
Development of rapid and reliable immunochemical methods for monitoring psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine; Pyb) and psilocin (dephosphorylated metabolite; Psi), the psychoactive compounds contained within hallucinogenic mushrooms (magic mushrooms), is desirable in order to identify these mushrooms and regulate their illicit use. Because no antibody was publicly available for this purpose, we generated two independent monoclonal antibodies (mAbs) against Pyb or Psi, and then developed enzyme-linked immunosorbent assays (ELISAs) by using them. To generate the specific antibodies, novel immunogenic conjugates were prepared by linking Pyb or Psi molecules to carrier proteins by modifying their 2-(N,N-dimethylamino)ethyl side chains. Spleen cells from mice immunized with these conjugates were fused with P3/NS1/1-Ag4-1 myeloma cells, and hybridoma clones secreting anti-Pyb and anti-Psi mAbs were established. These mAbs were characterized for their biochemical features and then applied to competitive ELISAs, which used microplates coated with Pyb or Psi linked with albumin. These ELISAs enabled the determination of Pyb or Psi with measurable ranges of ca. 0.20-20 or 0.040-2.0 μg/assay (limit of detection was 0.14 or 0.029 μg/assay), respectively. The related tryptamines were satisfactorily discriminated as exemplified by the cross-reactivity of the ELISA to determine Pyb (or Psi) with Psi (or Pyb) that were found to be 2.8 % (or <0.5 %), respectively. The Pyb and Psi contents in a dried powder of the hallucinogenic mushroom, Psilocybe cubensis, were determined to be 0.39 and 0.32 (w/w)%, respectively. The ELISAs developed using the current mAbs are promising tools for identifying illegal hallucinogenic mushrooms.
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Affiliation(s)
- Izumi Morita
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan
| | - Hiroyuki Oyama
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan
| | - Yuki Kiguchi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan
| | - Akari Oguri
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan
| | - Natsumi Fujimoto
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan
| | - Atsuko Takeuchi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan
| | - Rie Tanaka
- National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki 210-9501, Japan
| | - Jun Ogata
- National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki 210-9501, Japan
| | - Ruri Kikura-Hanajiri
- National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki 210-9501, Japan
| | - Norihiro Kobayashi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
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11
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Clonal array profiling of scFv-displaying phages for high-throughput discovery of affinity-matured antibody mutants. Sci Rep 2020; 10:14103. [PMID: 32839506 PMCID: PMC7445280 DOI: 10.1038/s41598-020-71037-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 08/04/2020] [Indexed: 12/14/2022] Open
Abstract
"Antibody-breeding" approach potentially generates therapeutic/diagnostic antibody mutants with greater performance than native antibodies. Therein, antibody fragments (e.g., single-chain Fv fragments; scFvs) with a variety of mutations are displayed on bacteriophage to generate diverse phage-antibody libraries. Rare clones with improved functions are then selected via panning against immobilized or tagged target antigens. However, this selection process often ended unsuccessful, mainly due to the biased propagation of phage-antibody clones and the competition with a large excess of undesirable clones with weaker affinities. To break radically from such panning-inherent problems, we developed a novel method, clonal array profiling of scFv-displaying phages (CAP), in which colonies of the initial bacterial libraries are examined one-by-one in microwells. Progenies of scFv-displaying phages generated are, if show sufficient affinity to target antigen, captured in the microwell via pre-coated antigen and detected using a luciferase-fused anti-phage scFv. The advantage of CAP was evidenced by its application with a small error-prone-PCR-based library (~ 105 colonies) of anti-cortisol scFvs. Only two operations, each surveying only ~ 3% of the library (9,400 colonies), provided five mutants showing 32–63-fold improved Ka values (> 1010 M−1), compared with the wild-type scFv (Ka = 3.8 × 108 M−1), none of which could be recovered via conventional panning procedures operated for the entire library.
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Xiao Y, Chen S, Zhang G, Li Z, Xiao H, Chen C, He C, Zhang R, Yang X. Simple and rapid nicotine analysis using a disposable silica nanochannel-assisted electrochemiluminescence sensor. Analyst 2020; 145:4806-4814. [PMID: 32588848 DOI: 10.1039/d0an00588f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Nicotine analysis is essential to medicine, toxicology and the tobacco industry. However, no simple, portable and disposable method was developed to meet their demands. Here, we report a simple, rapid and disposable silica nanochannel (SAN)-based electrochemiluminescence (ECL) sensor for nicotine analysis by simply assembling a SAN electrode with a paper cover. The sensing principle of the disposable sensor is based on the size exclusion effect and charge selectivity, which obviously prolong the sensor service time. We find that the sensor exhibits good specificity to nicotine, and most of the complex matrices are unlikely to impact the detection. The performance of the disposable sensor in cigarettes, e-cigarettes, nicotine gums, and lozenges is fully validated, showing satisfactory linearity, sensitivity (a limit of detection of 27.82 nM), and accuracy (a recovery between 96.00% and 106.51%). The disposable sensor can be potentially applied for on-site nicotine analysis.
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Affiliation(s)
- Yi Xiao
- Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, Department of Pharmacy, School of Medicine, Hunan Normal University, Changsha 410013, Hunan, China. and Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Hunan Normal University), Ministry of Education, China
| | - Suhua Chen
- Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, Department of Pharmacy, School of Medicine, Hunan Normal University, Changsha 410013, Hunan, China. and Hunan Provincial Maternal and Child Health Care Hospital, Changsha 410008, Hunan, China
| | - Guocan Zhang
- Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, Department of Pharmacy, School of Medicine, Hunan Normal University, Changsha 410013, Hunan, China.
| | - Zhimao Li
- Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, Department of Pharmacy, School of Medicine, Hunan Normal University, Changsha 410013, Hunan, China.
| | - Han Xiao
- Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, Department of Pharmacy, School of Medicine, Hunan Normal University, Changsha 410013, Hunan, China.
| | - Chuanpin Chen
- Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, Hunan 410013, China
| | - Chunlian He
- Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, Department of Pharmacy, School of Medicine, Hunan Normal University, Changsha 410013, Hunan, China.
| | - Ran Zhang
- Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, Department of Pharmacy, School of Medicine, Hunan Normal University, Changsha 410013, Hunan, China.
| | - Xiaoping Yang
- Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, Department of Pharmacy, School of Medicine, Hunan Normal University, Changsha 410013, Hunan, China.
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Oyama H, Kiguchi Y, Morita I, Yamamoto C, Higashi Y, Taguchi M, Tagawa T, Enami Y, Takamine Y, Hasegawa H, Takeuchi A, Kobayashi N. Seeking high-priority mutations enabling successful antibody-breeding: systematic analysis of a mutant that gained over 100-fold enhanced affinity. Sci Rep 2020; 10:4807. [PMID: 32179767 PMCID: PMC7075871 DOI: 10.1038/s41598-020-61529-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 02/27/2020] [Indexed: 01/05/2023] Open
Abstract
"Antibody-breeding" has provided therapeutic/diagnostic antibody mutants with greater performance than native antibodies. Typically, random point mutations are introduced into the VH and VL domains of parent antibodies to generate diverse libraries of single-chain Fv fragments (scFvs), from which evolved mutants are selected. We produced an scFv against estradiol-17β with 11 amino acid substitutions and a >100-fold improved affinity constant (Ka = 1.19 × 1010 M-1) over the parent scFv, enabling immunoassays with >30-fold higher sensitivity. We systematically analyzed contributions of these substitutions to the affinity enhancement. Comparing various partial scFv revertants based on their Kas indicated that a revertant with four substitutions (VH-L100gQ, VL-I29V, -L36M, -S77G) exhibited somewhat higher affinity (Ka = 1.46 × 1010 M-1). Finally, the VH-L100gQ substitution, occurring in VH complementarity-determining region (CDR) 3, was found to be the highest-priority for improving the affinity, and VL-I29V and/or VL-L36M cooperated significantly. These findings encouraged us to reconsider the potential of VH-CDR3-targeting mutagenesis, which has been frequently attempted. The substitution(s) wherein might enable a "high rate of return" in terms of selecting mutants with dramatically enhanced affinities. The "high risk" of generating a tremendous excess of "junk mutants" can be overcome with the efficient selection systems that we developed.
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Affiliation(s)
- Hiroyuki Oyama
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Yuki Kiguchi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Izumi Morita
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Chika Yamamoto
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Yuka Higashi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Miku Taguchi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Tatsuya Tagawa
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Yuri Enami
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Yuriko Takamine
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Hanako Hasegawa
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Atsuko Takeuchi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Norihiro Kobayashi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe, 658-8558, Japan.
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Lee K, Yoon T, Yang HS, Cha S, Cheon YP, Kashefi-Kheyrabadi L, Jung HI. All-in-one platform for salivary cotinine detection integrated with a microfluidic channel and an electrochemical biosensor. LAB ON A CHIP 2020; 20:320-331. [PMID: 31825049 DOI: 10.1039/c9lc01024f] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Medical disorders caused by second-hand smoke are a major public health concern worldwide. To estimate the level of second-hand smoke exposure, salivary diagnostics for cotinine analysis is a compelling alternative in conventional diagnostics using bio-fluids, such as blood and urine, owing to its simple and non-invasive collection method. However, there are several critical issues, such as tedious multisteps, demand for expertise, and field unavailability to collect and transport the purified saliva for further analysis. Here, an all-in-one platform is presented to simply collect real human saliva and directly deliver it onto the biosensing surface. The platform consists of a commercial cotton-swab-type collector, 3D-printed housing, and microfluidic channel integrated with an electrochemical competitive immunosensor to evaluate the level of salivary cotinine. The immunosensor is based on a competitive binding assay between cotinine-conjugated horseradish peroxidase (C-HRP) and cotinine for anti-cotinine binding sites. The current responses obtained from the HRP-thionine-H2O2 system decreased proportionally to the cotinine concentration. This immunosensor successfully detected its target over a range of 1 × 10-1 to 1 × 104 pg ml-1 with a low limit of detection of 6 × 10-2 pg ml-1 and a limit of quantification of 1 × 10-1 pg ml-1. In addition, the platform is applicable to various commercial cotton-swab-type saliva collectors and can successfully transfer the saliva in wide flow rates ranging from 0.1 to 30 ml min-1 without leakage or damage to the sensing surface. Furthermore, the practicality of the proposed platform was evaluated by measuring cotinine in real human saliva from eight non-smokers. The concentration of cotinine was from 45.7 to 890.8 pg ml-1, which was in good agreement with that measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The introduced all-in-one platform represented a reliable performance delivering simple and practical steps in salivary diagnostics.
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Affiliation(s)
- Kyungyeon Lee
- Department of Mechanical Engineering, Yonsei University, Seoul 03722, Republic of Korea.
| | - Taehee Yoon
- Department of Mechanical Engineering, Yonsei University, Seoul 03722, Republic of Korea.
| | - Hee-Seon Yang
- School of Biological Sciences and Chemistry, Sungshin Women's University, Seoul 02844, Republic of Korea
| | - Sunyeong Cha
- School of Biological Sciences and Chemistry, Sungshin Women's University, Seoul 02844, Republic of Korea
| | - Yong-Pil Cheon
- School of Biological Sciences and Chemistry, Sungshin Women's University, Seoul 02844, Republic of Korea
| | | | - Hyo-Il Jung
- Department of Mechanical Engineering, Yonsei University, Seoul 03722, Republic of Korea.
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Lin H, Wang Y, Wang T, Wu D, Li G, Deng C. Combined analysis of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and cotinine in urine by heart cutting two-dimensional LC-MS/MS. SEPARATION SCIENCE PLUS 2018. [DOI: 10.1002/sscp.201800117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Huaqing Lin
- Technology Center of Shanghai Tobacco Group; Shanghai P. R. China
- Department of Chemistry; Institutes of Biomedical Sciences; Fudan University; Shanghai P. R. China
| | - Yangzhong Wang
- Technology Center of Shanghai Tobacco Group; Shanghai P. R. China
| | - Tiannan Wang
- Technology Center of Shanghai Tobacco Group; Shanghai P. R. China
| | - Da Wu
- Technology Center of Shanghai Tobacco Group; Shanghai P. R. China
| | - Gang Li
- Technology Center of Shanghai Tobacco Group; Shanghai P. R. China
| | - Chunhui Deng
- Department of Chemistry; Institutes of Biomedical Sciences; Fudan University; Shanghai P. R. China
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Kiguchi Y, Oyama H, Morita I, Katayama E, Fujita M, Narasaki M, Yokoyama A, Kobayashi N. Antibodies and Engineered Antibody Fragments against M13 Filamentous Phage to Facilitate Phage-Display-Based Molecular Breeding. Biol Pharm Bull 2018; 41:1062-1070. [PMID: 29962401 DOI: 10.1248/bpb.b18-00162] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Antibodies are essential for characterizing various analytes. "Molecular-breeding" approaches enable rapid generation of antibody mutants with desirable antigen-binding abilities. Typically, prototype antibodies are converted to single-chain Fv fragments (scFvs), and random mutations are genetically introduced to construct molecular libraries with a vast diversity. Improved species therein are then isolated via phage display genotype-phenotype-connecting systems to separate them from a large excess of nonspecific scFvs. During these experiments, counting of phage particles is routinely performed. However, current methods depend on the time-consuming overnight cultivation of phage-infected bacteria on agar plates to estimate phage numbers as plaque-forming units (pfu) or colony-forming units, the results of which fluctuate considerably. Immunochemical systems capturing phage particles should be a more convenient and robust alternative. We therefore generated monoclonal antibodies against M13 filamentous phage, which is commonly used for phage display, by employing hybridoma technology. Combinatorial use of two such antibodies (Ab-M13#53 and #71; both specific to the major coat protein pVIII) enabled development of a sandwich enzyme-linked immunosorbent assay (ELISA) that could measure ca. 107-1010 phage pfu/mL. To construct a more convenient system, Ab-M13#71 was converted to the scFv form and further fused with an alkaline phosphatase variant. Using this fusion protein, the sandwich ELISA enabled rapid (within 90 min) and reliable phage counting without reducing the sensitivity, and the results were reasonably consistent with those of infection-based methods. The present anti-phage antibodies and scFvs might also enable visualization of individual phage particles by combining them with sensitive fluorescent staining.
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Morita I, Oyama H, Kanda Y, Yasuo M, Ito A, Toyota M, Hayashi Y, Yokoyama T, Kobayashi N. Enantioselective Monoclonal Antibodies for Detecting Ketamine to Crack Down on Illicit Use. Biol Pharm Bull 2018; 41:123-131. [PMID: 29311474 DOI: 10.1248/bpb.b17-00762] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ketamine (KT) is a chiral anesthetic agent, (R)- and (S)-enantiomers of which differ in their pharmacological properties. KT has become one of the most commonly used illicit drugs in the world, thus, rapid and feasible on-site testing is required to crack down on the illicit use. Although immunochemical approach with specific antibodies is promising for this purpose, in practice anti-KT antibodies are difficult to obtain. We here disclose generation of monoclonal antibodies against KT. Mice were immunized with either (a) commercially-available or (b) in-house-prepared KT-albumin conjugates. Splenocytes from these mouse groups (a and b) were separately fused with P3/NS1/1-Ag4-1 myeloma cells. After standard screening and cloning, we established 5 hybridoma clones: 2 were derived from group-a mice [generating Ab-KT(a)#2 and #37] and 3 were from group-b mice [generating Ab-KT(b)#9, #13, and #45]. These antibodies exhibited practical performance in competitive enzyme-linked immunosorbent assay systems. When (±)-KT·hydrochloride (HCl) was used as the competitor, dose-response curves showed midpoint values of 30 and 70 ng/assay (a-series antibodies) and 2.0-3.0 ng/assay (b-series antibodies). Remarkably, the a-series antibodies were specific for (S)-KT·HCl, while the b-series antibodies were specific for (R)-KT·HCl. Ab-KT(a)#2 (Ka, 7.5×107 M-1) and Ab-KT(b)#45 (Ka, 7.7×108 M-1) exhibited the highest enantioselectivity for each group, and cross-reactivity with the (R)- and (S)-antipodes was 1.3 and 1.7%, respectively. The hybridomas established here are also valuable as a source of genetic information for the anti-KT antibodies, which is required for progressing to next-generation technologies using genetically engineered antibodies.
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Affiliation(s)
| | | | | | | | - Aya Ito
- Kobe Pharmaceutical University
| | - Masahiro Toyota
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University
| | - Yoshinori Hayashi
- Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University
| | - Takeshi Yokoyama
- Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University
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Zhou Y, Wang P, Wang L, Fu Z. Chemiluminescent detection integrated with microdialysis sampling for label-free measuring the affinity of ractopamine monoclonal antibody. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 201:19-23. [PMID: 29727792 DOI: 10.1016/j.saa.2018.04.047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 04/09/2018] [Accepted: 04/22/2018] [Indexed: 06/08/2023]
Abstract
A novel label-free protocol was developed for measuring the affinity between ractopamine and its monoclonal antibody (McAb) based on microdialysis (MD) on-line sampling integrated with flow injection chemiluminescent detection. In this study, unbound ractopamine was sampled by MD probe from homogeneous immunoreaction equilibrious systems, and then real-time quantified using flow injection chemiluminescent detection. The quantified concentrations of unbound ractopamine in the immunoreaction equilibrious systems were treated with Scatchard analysis and Klotz analysis to obtain the affinity constant. The mean recovery of MD probe for sampling ractopamine was found to be 24.2%. The affinity constants calculated by Scatchard analysis and Klotz analysis both were 1.0 × 106 M-1, indicating that the investigated ractopamine mouse McAb was a medium-affinity antibody. The result showed good agreement with that obtained from thiocyanate elution test. This protocol for measuring antibody affinity is free of protein conjugation of hapten and enzyme labeling of McAb. Therefore it avoids affinity decrease resulting from steric hindrance, occupancy of the antigenic determinants, and deactivation of antibody, which has been frequently encountered in the reported conventional approaches. It opens up a new pathway for direct measurement of antibody affinity with a facile, rapid, accurate and low-cost approach.
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Affiliation(s)
- Yali Zhou
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Ministry of Education), College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China
| | - Pingshi Wang
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Ministry of Education), College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China
| | - Lin Wang
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Ministry of Education), College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China.
| | - Zhifeng Fu
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Ministry of Education), College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China.
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Ramdzan AN, Almeida MIG, McCullough MJ, Segundo MA, Kolev SD. Determination of salivary cotinine as tobacco smoking biomarker. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2018.04.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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20
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Oyama H, Morita I, Kiguchi Y, Morishita T, Fukushima S, Nishimori Y, Niwa T, Kobayashi N. A Single-Step "Breeding" Generated a Diagnostic Anti-cortisol Antibody Fragment with Over 30-Fold Enhanced Affinity. Biol Pharm Bull 2017; 40:2191-2198. [PMID: 29199242 DOI: 10.1248/bpb.b17-00633] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cortisol levels in bodily fluids represent a useful index for pituitary-adrenal function, and thus practical anti-cortisol antibodies are required. We have studied "antibody-breeding" approaches, which involve in vitro evolution of antibodies to improve their antigen-binding performances. Here, we produced an antibody fragment to measure serum cortisol levels with over 30-fold enhanced affinity after single mutagenesis and selection steps. A mouse anti-cortisol antibody, Ab-CS#3, with insufficient affinity for practical use, was chosen as the prototype antibody. A "wild-type" single-chain Fv fragment (wt-scFv; Ka, 3.4×108 M-1) was prepared by bacterial expression of a fusion gene combining the VH and VL genes for this antibody. Then, random point mutations were generated separately in VH or VL by error-prone PCR, and the resulting products were used to assemble scFv genes, which were displayed on filamentous phages. Repeated panning of the phage library identified a mutant scFv (scFv#m1-L10) with an over 30-fold enhanced affinity (Ka 1.2×1010 M-1). Three amino acid substitutions (Cys49Ser, Leu54Pro, and Ser63Gly) were observed in its VL sequence. In a competitive enzyme-linked immunosorbent assay (ELISA), the mutant scFv generated dose-response curves with measuring range ca. 0.03-0.6 ng/assay cortisol, midpoint of which (0.15 ng/assay) was 7.3-fold lower than that of wt-scFv. Although cortisone, 11-deoxycortisol, and prednisolone showed considerable cross-reactivity, the mutant scFv should enable sensitive routine cortisol assays, except for measurement after metyrapone or high-dose of prednisolone administrations. Actually, cortisol levels of control sera obtained with the scFv-based ELISA were in the reference range.
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Affiliation(s)
| | | | | | | | | | | | - Toshifumi Niwa
- Department of Medical Technology, School of Health Sciences, Tohoku University
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