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Fei J, Jiang J, Bai Y, Wu W, Zhao X, Yu W, Wen K, Yu X, Shen J, Wang Z. A Proof-of-Concept Sandwich Enzyme-Linked Immunoassay Development for Small Molecules. Anal Chem 2023; 95:14665-14674. [PMID: 37679861 DOI: 10.1021/acs.analchem.3c02557] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Abstract
A sandwich immunoassay theoretically exhibits higher sensitivity and specificity compared to a competitive counterpart; however, it is extremely difficult to obtain a pair of antibodies that can bind to a small molecule simultaneously, which is always thought to be a single epitope. In the present study, abamectin (ABM) was selected to prove the effect of hapten design and antibody recognition properties on the development of a sandwich immunoassay for small molecules. First, the epitopes of ABM were roughly located, and epitope distances were determined. Then, two haptens were designed by introducing spacer arms at the C4″-OH and C5-OH of ABM, respectively, aiming to provide the longest epitope distances. A total of seven rabbit polyclonal antibodies (pAbs) and 21 mouse monoclonal antibodies (mAbs) with various recognition properties were obtained. Extensive combinatorial associations of antibody pairs for simultaneously binding to ABM were performed, and only two mAb-mAb pairs were observed to achieve a sandwich immunoassay for ABM with a total success rate of 0.27%. The best mAb pair for sandwich immunoassay was confirmed by surface plasmon resonance, used to develop a sandwich immunoassay, and then evaluated by cross-reactivities and molecular docking with structurally similar analogues and abamectin. Altogether, the study provided a theoretical foundation as well as practical experience and demonstrated the importance of careful hapten design and extensive antibody screening to successfully establish the sandwich immunoassay for small molecules.
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Affiliation(s)
- Jie Fei
- National Key Laboratory of Veterinary Public Health Safety, Beijing Key Laboratory of Detection Technology for Animal Derived Food Safety, College of Veterinary Medicine, China Agricultural University, 100193 Beijing, People's Republic of China
| | - Jiaqun Jiang
- National Key Laboratory of Veterinary Public Health Safety, Beijing Key Laboratory of Detection Technology for Animal Derived Food Safety, College of Veterinary Medicine, China Agricultural University, 100193 Beijing, People's Republic of China
| | - Yuchen Bai
- National Key Laboratory of Veterinary Public Health Safety, Beijing Key Laboratory of Detection Technology for Animal Derived Food Safety, College of Veterinary Medicine, China Agricultural University, 100193 Beijing, People's Republic of China
| | - Weilin Wu
- National Key Laboratory of Veterinary Public Health Safety, Beijing Key Laboratory of Detection Technology for Animal Derived Food Safety, College of Veterinary Medicine, China Agricultural University, 100193 Beijing, People's Republic of China
| | - Xiangjun Zhao
- National Key Laboratory of Veterinary Public Health Safety, Beijing Key Laboratory of Detection Technology for Animal Derived Food Safety, College of Veterinary Medicine, China Agricultural University, 100193 Beijing, People's Republic of China
| | - Wenbo Yu
- National Key Laboratory of Veterinary Public Health Safety, Beijing Key Laboratory of Detection Technology for Animal Derived Food Safety, College of Veterinary Medicine, China Agricultural University, 100193 Beijing, People's Republic of China
| | - Kai Wen
- National Key Laboratory of Veterinary Public Health Safety, Beijing Key Laboratory of Detection Technology for Animal Derived Food Safety, College of Veterinary Medicine, China Agricultural University, 100193 Beijing, People's Republic of China
| | - Xuezhi Yu
- National Key Laboratory of Veterinary Public Health Safety, Beijing Key Laboratory of Detection Technology for Animal Derived Food Safety, College of Veterinary Medicine, China Agricultural University, 100193 Beijing, People's Republic of China
| | - Jianzhong Shen
- National Key Laboratory of Veterinary Public Health Safety, Beijing Key Laboratory of Detection Technology for Animal Derived Food Safety, College of Veterinary Medicine, China Agricultural University, 100193 Beijing, People's Republic of China
| | - Zhanhui Wang
- National Key Laboratory of Veterinary Public Health Safety, Beijing Key Laboratory of Detection Technology for Animal Derived Food Safety, College of Veterinary Medicine, China Agricultural University, 100193 Beijing, People's Republic of China
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2
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Gorris HH, Soukka T. What Digital Immunoassays Can Learn from Ambient Analyte Theory: A Perspective. Anal Chem 2022; 94:6073-6083. [PMID: 35404586 DOI: 10.1021/acs.analchem.1c05591] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Immunoassays are important tools for clinical diagnosis as well as environmental and food analysis because they enable highly sensitive and quantitative measurements of analyte concentrations. In the 1980s, Roger Ekins suggested to improve the sensitivity of immunoassays by employing microspot assays, which are carried out under ambient analyte conditions and do not change the bulk analyte concentration of a sample during a measurement. More recently, the measurement of single analyte molecules has additionally attracted wide research interest. Although the ability to detect a single analyte molecule is not synonymous with the highest analytical sensitivity, single-molecule detection makes new routes accessible to avoiding background noise. This perspective follows the development of solid-phase immunoassays from the design of label techniques to single-molecule (digital) assays against the backdrop of Ekins's fundamental work on immunoassay theory. The essential aspects of both ambient analyte and digital assay approaches are presented as a guideline to finding a balance between the speed, sensitivity, and precision of immunoassays.
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Affiliation(s)
- Hans H Gorris
- Department of Biochemistry, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - Tero Soukka
- Department of Life Technologies/Biotechnology, University of Turku, Kiinamyllynkatu 10, 20520 Turku, Finland
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3
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Mills C, Campbell K. A new chapter for anti-idiotypes in low molecular weight compound immunoassays. Trends Biotechnol 2022; 40:1102-1120. [DOI: 10.1016/j.tibtech.2022.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 02/16/2022] [Accepted: 02/22/2022] [Indexed: 11/25/2022]
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4
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Fu HJ, Chen ZJ, Wang H, Luo L, Wang Y, Huang RM, Xu ZL, Hammock B. Development of a sensitive non-competitive immunoassay via immunocomplex binding peptide for the determination of ethyl carbamate in wine samples. JOURNAL OF HAZARDOUS MATERIALS 2021; 406:124288. [PMID: 33525128 PMCID: PMC8893042 DOI: 10.1016/j.jhazmat.2020.124288] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 10/07/2020] [Accepted: 10/13/2020] [Indexed: 05/03/2023]
Abstract
Ethyl carbamate is a group of 2A carcinogen ubiquitously existed in fermented foods. The monitoring of its residues was important for evaluating the potential risk to human beings. Immunoassays with good accuracy and simplicity are great analytical tools for small molecule contaminants. However, it is typically confined in a competitive mode for small molecules with drawback of the sensitivity curbing. In this work, three different phages displayed peptides with capability of identifying the xanthyl ethyl carbamate immunocomplex were isolated from phage library. The binding mechanism of peptides and immunocomplex was studied by computer-assisted simulation. Results indicated that the xanthydrol group of xanthyl ethyl carbamate and the Asn-32 and Asn-92 residues of the antibody light chain were mainly responsible for binding. Simultaneously, a sensitive non-competitive immunoassay for detecting ethyl carbamate in wine samples was developed. The established method exhibited a limit of detection of 5.4 ng/mL and a linear range from 8.7 ng/mL to 32 ng/mL for wine samples. In comparison with the conventional competitive immunoassay, the sensitivity of the proposed non-competitive immunoassay was improved by 17-fold. The results of the immunoassay were validated by a standard ultra-performance liquid chromatography-quadrupole/orbitrap high-resolution mass spectrometry, which illustrated good reliability of the proposed assay.
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Affiliation(s)
- Hui-Jun Fu
- Guangdong Provincial Key Laboratory of Food Quality and Safety/ Guangdong Laboratory of Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Zi-Jian Chen
- Guangdong Provincial Key Laboratory of Food Quality and Safety/ Guangdong Laboratory of Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Hong Wang
- Guangdong Provincial Key Laboratory of Food Quality and Safety/ Guangdong Laboratory of Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Lin Luo
- Guangdong Provincial Key Laboratory of Food Quality and Safety/ Guangdong Laboratory of Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Yu Wang
- Guangzhou Institute for Food Control, Guangzhou 510410, China.
| | - Ri-Ming Huang
- Guangdong Provincial Key Laboratory of Food Quality and Safety/ Guangdong Laboratory of Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Zhen-Lin Xu
- Guangdong Provincial Key Laboratory of Food Quality and Safety/ Guangdong Laboratory of Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Bruce Hammock
- Department of Entomology and UCD Comprehensive Cancer Center, University of California, Davis 95616, CA, United States.
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5
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Li Y, Zhang G, Mao X, Yang S, De Ruyck K, Wu Y. High sensitivity immunoassays for small molecule compounds detection – Novel noncompetitive immunoassay designs. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2018.04.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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6
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Liu A, Anfossi L, Shen L, Li C, Wang X. Non-competitive immunoassay for low-molecular-weight contaminant detection in food, feed and agricultural products: A mini-review. Trends Food Sci Technol 2018. [DOI: 10.1016/j.tifs.2017.11.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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7
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Akter S, Vehniäinen M, Spoof L, Nybom S, Meriluoto J, Lamminmäki U. Broad-Spectrum Noncompetitive Immunocomplex Immunoassay for Cyanobacterial Peptide Hepatotoxins (Microcystins and Nodularins). Anal Chem 2016; 88:10080-10087. [DOI: 10.1021/acs.analchem.6b02470] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sultana Akter
- Molecular
Biotechnology and Diagnostics, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland
| | - Markus Vehniäinen
- Molecular
Biotechnology and Diagnostics, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland
| | - Lisa Spoof
- Biochemistry,
Faculty of Science and Engineering, Åbo Akademi University, FI-20520 Turku, Finland
| | - Sonja Nybom
- Biochemistry,
Faculty of Science and Engineering, Åbo Akademi University, FI-20520 Turku, Finland
| | - Jussi Meriluoto
- Biochemistry,
Faculty of Science and Engineering, Åbo Akademi University, FI-20520 Turku, Finland
| | - Urpo Lamminmäki
- Molecular
Biotechnology and Diagnostics, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland
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8
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HE J, LIANG Y, FAN MT, LIU XJ. Preparation of Anti-idiotype Antibodies of O,O-Dimethyl Organophosphorus Pesticides by Phage Display Technology. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2011. [DOI: 10.1016/s1872-2040(10)60415-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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9
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HE J, FAN MT, LIANG Y, LIU XJ. Application of Anti-idiotype Antibody in Small Molecules Immunoassay. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2010. [DOI: 10.1016/s1872-2040(09)60068-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Abstract
Most steroid disorders of the adrenal cortex come to clinical attention in childhood and in order to investigate these problems, there are many challenges to the laboratory which need to be appreciated to a certain extent by clinicians. The analysis of sex steroids in biological fluids from neonates, over adrenarche and puberty present challenges of specificities and concentrations often in small sample sizes. Different reference ranges are also needed for interpretations. For around 40 years, quantitative assays for the steroids and their regulatory peptide hormones have been possible using immunoassay techniques. Problems are recognised and this review aims to summarise the benefits and failings of immunoassays and introduce where tandem mass spectrometry is anticipated to meet the clinical needs for steroid analysis in paediatric endocrine investigations. It is important to keep a dialogue between clinicians and the laboratory, especially when any laboratory result does not make sense in the clinical investigation.
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Affiliation(s)
- John W Honour
- Clinical Biochemistry, University College London Hospitals, London, England.
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11
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Pulli T, Höyhtyä M, Söderlund H, Takkinen K. One-step homogeneous immunoassay for small analytes. Anal Chem 2007; 77:2637-42. [PMID: 15828804 DOI: 10.1021/ac048379l] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have developed a one-step, homogeneous noncompetitive immunoassay for small analytes using recombinant antibodies and morphine as the model analyte. A highly specific antibody against the immune complex (IC) formed between an anti-morphine antibody and morphine was selected from a naive scFv phage display library. The in vitro phage library selection procedure avoids the difficulties associated with the production of anti-IC antibodies by animal immunization. The anti-morphine and the anti-IC antibodies were labeled with a pair of fluorescence resonance energy transfer (FRET) fluorophores. In the FRET assay the labeled antibodies were incubated with saliva samples spiked with morphine, codeine, or heroin. Within 2 min, 5 ng/mL morphine, which is clearly under the recommended cutoff level, was detected without cross-reactivity to codeine or heroin. This assay principle is also widely applicable to other small analytes.
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Affiliation(s)
- Timo Pulli
- VTT Biotechnology, Tietotie 2, P.O. Box 1500, FI-02044 VTT, Espoo, Finland.
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12
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Volland H, Pradelles P, Taran F, Buscarlet L, Creminon C. Recent developments for SPIE-IA, a new sandwich immunoassay format for very small molecules. J Pharm Biomed Anal 2004; 34:737-52. [PMID: 15019052 DOI: 10.1016/s0731-7085(03)00560-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2003] [Indexed: 11/18/2022]
Abstract
Recent publications describing new elegant approaches to assay small analytes using noncompetitive format were briefly reviewed. Among these methods, we have developed a new protocol, named SPIE-IA, which involves a cross-linking step achieved using chemical hombifunctional reagents, UV irradiation or free radicals. This new method proved to be useful to detect naturally occurring analyte/antibody complexes or to protect the analytes against degradation by peptidases. On the other hand, SPIE-IA could allow to study the adverse biological effects of UV and some aspects of free radical chemistry or to evaluate the antioxidant activity of molecules.
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Affiliation(s)
- Hervé Volland
- CEA, Service de Pharmacologie et d'Immunologie, DRM/DSV, CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France.
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13
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Yokozeki T, Ueda H, Arai R, Mahoney W, Nagamune T. A homogeneous noncompetitive immunoassay for the detection of small haptens. Anal Chem 2002; 74:2500-4. [PMID: 12069229 DOI: 10.1021/ac015743x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We describe a noncompetitive homogeneous immunoassay for small haptens based on the antigen-dependent reassociation of antibody variable domains and beta-galactosidase (beta-gal) complementation (open sandwich enzymatic complementation immunoassay). As a model system, the reassociation of two fusion proteins, an anti 4-hydroxy-3-nitrophenylacetyl (NP) antibody heavy-chain variable-region fragment fused to an N-terminal deletion mutant of beta-gal (V(H)delta alpha) and the light-chain variable-region fragment fused to a C-terminal deletion mutant of beta-gal (V(L)delta omega), was monitored by the enzymatic complementation between the two. Upon simple mixing of the reagents with the sample, an antigen (NP)-dependent increase in enzymatic activity was observed. When 5-iodo-NP was measured, a 10 times higher sensitivity was observed, probably due to its higher affinity. Compared with our corresponding heterogeneous open sandwich enzyme-linked immunosorbent assay, approximately 1000-fold improvement in the sensitivity was attained, probably due to lower background V(H)-V(L) association. In addition, the assay required less time, handling, sample volume, and assay reagents.
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Affiliation(s)
- Tomoichi Yokozeki
- Department of Chemistry and Biotechnology, School of Engineering, University of Tokyo, Japan
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14
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Hafner FT, Kautz RA, Iverson BL, Tim RC, Karger BL. Noncompetitive immunoassay of small analytes at the femtomolar level by affinity probe capillary electrophoresis: direct analysis of digoxin using a uniform-labeled scFv immunoreagent. Anal Chem 2000; 72:5779-86. [PMID: 11128936 DOI: 10.1021/ac000853+] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A general method for noncompetitive immunoassay of small analytes using affinity probe capillary electrophoresis (APCE) is demonstrated using digoxin as a model analyte. A uniform immunoreagent was prepared from a single-chain antibody (scFv) gene specific for digoxin. Site-directed mutagenesis introduced a unique cysteine residue for uniform labeling with a thiol-reactive fluorochrome. After expression in E. coli, the scFv was purified by immobilized metal affinity chromatography (IMAC) using an added C-terminal 6-histidine sequence. The protein was renatured and labeled while immobilized on the IMAC resin. After 0.02-microm filtration to remove microaggregates, the resulting reagent was highly uniform and stable at -12 degrees C for at least 1 year. Three formats of APCE using the scFv reagent were explored. A "mix-and-inject" assay optimized for low detection limits demonstrated analysis of 10 pM digoxin in aqueous standard solutions in 10 min. A rapid mix-and-inject format in a short capillary allowed detection of 1 nM digoxin in 1 min. Digoxin samples in serum and urine were injected directly after 10-fold dilution. In combination with solid-phase extraction, 400 fM digoxin was detected in 1 mL of serum. Including solid-phase extraction, reproducibility was within 2.5%, and the linear range was 3 orders of magnitude. The strategy adopted in this paper should be of general use in the low-level analysis of small analytes.
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Affiliation(s)
- F T Hafner
- Barnett Institute and Department of Chemistry, Northeastern University, Boston, Massachusetts 02115, USA
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15
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Giraudi G, Anfossi L, Rosso I, Baggiani C, Giovannoli C, Tozzi C. A general method to perform a noncompetitive immunoassay for small molecules. Anal Chem 1999; 71:4697-700. [PMID: 10546535 DOI: 10.1021/ac981282c] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A new general method to perform a noncompetitive immunoassay for low-molecular-mass analytes (less than 6000 Da) is described and checked using cortisol as a model system. The method is based on the use of a "polydentate ligand" (cortisol-poly(L-lysine) conjugate) able to block the antibody sites unoccupied by the analyte, followed by the replacement of an antibody-bound analyte by an enzyme-labeled analyte (cortisol-horseradish peroxidase), and permits the direct measurement of the analyte bound sites. The observed signal shows a near-linear correlation with the analyte concentration. The characteristics of interactions between the analyte and polydentate ligand with the specific antibody were studied to perform a preliminary evaluation of the noncompetitive immunoassay for cortisol. The noncompetitive assay was compared with a competitive immunoassay obtained under the same conditions and using the same reagents. The results of the experiments showed a lower detection limit for the noncompetitive model (0.15 ng mL-1 rather than 0.72 ng mL-1), emphasizing that the model is successful. Moreover, as the polydentate ligand is prepared from the same hapten used for the immunogen synthesis, this type of noncompetitive immunoassay appears generally applicable to all small molecules for which antibodies have been obtained.
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Affiliation(s)
- G Giraudi
- Dipartimento di Chimica Analitica, Università di Torino, Italy.
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16
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Buscarlet L, Grassi J, Créminon C, Pradelles P, Dupret-Carruel J, Jolivet M, Mons S. Cross-linking of 17 beta-estradiol to monoclonal antibodies by direct UV irradiation: application to an enzyme immunometric assay. Anal Chem 1999; 71:1002-8. [PMID: 10079761 DOI: 10.1021/ac980870n] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ultraviolet irradiation was used to cross-link 17 beta-estradiol directly to monoclonal anti-17 beta-estradiol antibodies coated on 96-well microtiter plates. Cross-linking efficiency was directly correlated with both irradiation energy and wave-length. The best results were obtained at 254 (10 J/cm2, 45-min irradiation) and 312 nm (40 J/cm2, 160-min irradiation). The irradiation fully denatured both individual molecules (i.e., 17 beta-estradiol and monoclonal anti-17 beta-estradiol antibody), but 17 beta-estradiol was at least partly protected when immunologically bound to the paratope of the antibody. Four different monoclonal anti-17 beta-estradiol antibodies yielded positive results, demonstrating that this photo-cross-linking has considerable potential. We used this original approach to develop a new enzyme immunometric assay of 17 beta-estradiol based on our previously described immunometric procedure, solid-phase immobilized epitope immunoassay, which uses chemical agents to cross-link haptens via amino groups to specific antibodies. The assay was specific (no cross-reactivity with other natural steroids), precise, and sensitive (detection limit of 38 pg/mL in human serum). It correlated well with two competitive commercial immunoassays when tested on 40 human sera.
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Affiliation(s)
- L Buscarlet
- CEA, Laboratoire d'Etudes Radioimmunologiques, SPI/DRM/DSV, CEA/Saclay, Gif-sur-Yvette, France
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17
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O'Connor T, Gosling JP. The dependence of radioimmunoassay detection limits on antibody affinity. J Immunol Methods 1997; 208:181-9. [PMID: 9433473 DOI: 10.1016/s0022-1759(97)00148-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Competitive radioimmunoassay standard curves for progesterone were established with tritiated progesterone and six different anti-progesterone monoclonal antibodies ranging in affinity from 1.23 x 10(8) to 2.82 x 10(10) l/mol. The detection limits for these curves ranged from 133 to 6,670 pmol/l final assay concentration (16.7 to 839.1 pg/tube). Separately, a mass-action mathematical model was used to predict lower detection limits for assays run under equivalent conditions with the six antibodies. When compared to the experimental data the predictions were reliable for the higher affinity antibodies but became less accurate as the affinity decreased.
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Affiliation(s)
- T O'Connor
- Department of Biochemistry, University College, Galway, Ireland
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18
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Tamate K, Charleton M, Gosling JP, Egan D, Ishikawa M, Fottrell PF, Kane MM. Direct colorimetric monoclonal antibody enzyme immunoassay for estradiol-17β in saliva. Clin Chem 1997. [DOI: 10.1093/clinchem/43.7.1159] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
AbstractWe developed a direct microtiter plate enzyme immunoassay to measure estradiol-17β in saliva. The assay has a commercially available monoclonal antibody, raised against estradiol-17β–6-carboxymethyloxime–bovine serum albumin, and a homologous horseradish peroxidase conjugate measured colorimetrically. The detection limit (equivalent to B0 − 3 SD) is 365 amol/well or 7.3 pmol/L when 50-μL samples are assayed. Cross-reactivity with estrone and estriol, testosterone, or progesterone is <0.2%. Estradiol-17β was measured in daily samples over five natural menstrual cycles and eight cycles stimulated as a preliminary to in vitro fertilization, and the concentrations and fluctuations found agreed with previously published data. This method gives results in ∼3 h and may be useful for fertility monitoring and management.
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Affiliation(s)
- Kenichi Tamate
- National Diagnostics Centre—Bioresearch Ireland, University College, Galway, Ireland
- Department of Obstetrics & Gynecology, Asahikawa Medical College, Japan
| | - Margaret Charleton
- National Diagnostics Centre—Bioresearch Ireland, University College, Galway, Ireland
| | - James P Gosling
- Department of Biochemistry, University College, Galway, Ireland
| | - Declan Egan
- Fertility Unit, Department of Obstetrics & Gynecology, University College Hospital, Galway, Ireland
| | - Mutsuo Ishikawa
- Department of Obstetrics & Gynecology, Asahikawa Medical College, Japan
| | | | - Marian M Kane
- National Diagnostics Centre—Bioresearch Ireland, University College, Galway, Ireland
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19
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Kohen F, Bagci H, Barnard G, Bayer EA, Gayer B, Schindler DG, Ainbinder E, Wilchek M. Preparation and properties of anti-biotin antibodies. Methods Enzymol 1997; 279:451-63. [PMID: 9211297 DOI: 10.1016/s0076-6879(97)79049-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- F Kohen
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
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20
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Abstract
Major developments continue to be reported in key areas of immunoassay technology. Following the development of excellent signal generation methods, attention has shifted to the development of immunochemical methods and instrumentation to provide convenient systems of high performance. Important advances have been made in the design of immunochemical approaches that permit the replacement of competitive format assays for small molecules, such as drugs, metabolites and pollutants, with non-competitive formats, bringing advantages previously seen only with large molecular analytes. Bispecific antibodies and recombinant proteins are also beginning to impact immunodiagnostics, with the promise of even more highly specified reagents. Improvements in automation have brought the facility of homogeneous systems to high-throughput and high-performance heterogeneous systems. Similarly, 'point of need' testing continues to progress. Through all of these advances, systems are evolving according to the needs of users in terms of operator convenience, accuracy, specificity, speed, robustness, and sensitivity.
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Affiliation(s)
- C H Self
- Department of Clinical Biochemistry, University of Newcastle upon Tyne, UK
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21
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Barnard G, Osher J, Lichter S, Gayer B, De Boever J, Limor R, Ayalon D, Kohen F. The measurement of progesterone in serum by a non-competitive idiometric assay. Steroids 1995; 60:824-9. [PMID: 8650706 DOI: 10.1016/0039-128x(95)00144-f] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A novel non-competitive idiometric time-resolved fluoroimmunoassay for the determination of serum progesterone was developed, based on the use of two types of anti-idiotypic antibody that recognize different epitopes within the hypervariable region of the primary antiprogesterone antibody. The first anti-idiotype, the betatype, competes with progesterone for an epitope of the primary antiprogesterone antibody at the binding site. The second anti-idiotype, the alphatype, binds to the antiprogesterone antibody in the presence of progesterone, but does not bind to the betatype antiprogesterone complex due to epitope proximity. In the present configuration, the biotinylated alphatype was captured onto anti-biotin IgG which was immobilized on microtiter wells. Reaction mixtures containing europium-labeled antiprogesterone antibody complexed sequentially with progesterone in standards or serum samples and with the betatype anti-idiotypic antibody were then reacted with the immobilized alphatype anti-idiotypic antibody. After 30 min of incubation, the fluorescence of europium is measured by time-resolved fluorescence and is proportional to the concentration of progesterone over the range 0-320 nmol/mL. The method demonstrates good sensitivity, precision, and comparability with a direct competitive radioimmunoassay. The idiometric assay for progesterone is suitable for dipstick technology and biosensors.
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Affiliation(s)
- G Barnard
- Department of Hormone Research, Weizmann Institute of Science, Rehovot, Israel
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