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Development of a multiplexing potency assay using upconverting nanoparticles-based luminescence resonance energy transfer. J Immunol Methods 2022; 510:113364. [PMID: 36179896 DOI: 10.1016/j.jim.2022.113364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 09/22/2022] [Accepted: 09/22/2022] [Indexed: 12/31/2022]
Abstract
A homogeneous particle-based immunoassay using upconverting nanoparticles (UCNPs) has been developed for multiplexing potency analysis of two different therapeutic monoclonal antibodies (mAbs) in a fixed-combination formulation.The UCNP, considered as the best donor lumiphore for luminescence resonance energy transfer (LRET), offers long lasting excitation state and increased signal-to-noise (S/N) ratio due to low autofluorescence effect and light scattering from near infrared (NIR) excitation. In this study, the dose-response curves for each therapeutic mAb were generated using two distinct UCNPs. This proof-of-concept LRET-based immunoassay demonstrated a novel approach for increasing testing throughput and analyzing the potency of mixed therapeutic mAbs in co-formulated products.
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Doménech-Carbó MT, Doménech-Carbó A. Spot tests: past and present. CHEMTEXTS 2022; 8:4. [PMID: 34976574 PMCID: PMC8710564 DOI: 10.1007/s40828-021-00152-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 10/11/2021] [Indexed: 11/21/2022]
Abstract
Microchemistry, i.e., the chemistry performed at the scale of a microgram or less, has its roots in the late eighteenth and early nineteenth centuries. In the first half of the twentieth century a wide range of spot tests have been developed. For didactic reasons, they are still part of the curriculum of chemistry students. However, they are even highly important for applied analyses in conservation of cultural heritage, food science, forensic science, clinical and pharmacological sciences, geochemistry, and environmental sciences. Modern pregnancy tests, virus tests, etc. are the most recent examples of sophisticated spot tests. The present ChemTexts contribution aims to provide an overview of the past and present of this analytical methodology.
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Affiliation(s)
- María Teresa Doménech-Carbó
- Institut de Restauració del Patrimoni, Universitat Politècnica de València, Camí de Vera 14, 46022 Valencia, Spain
| | - Antonio Doménech-Carbó
- Departament de Química Analítica, Universitat de València. Dr. Moliner, 50, Burjassot, 46100 Valencia, Spain
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Wang R, Zong C, Li G, Wang J, Kong T, Li F, Chang J. High-throughput immunosensor chip coupled with a fluorescent DNA dendrimer for ultrasensitive detection of cardiac troponin T. RSC Adv 2021; 11:27523-27529. [PMID: 35480665 PMCID: PMC9037839 DOI: 10.1039/d1ra03420k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 07/13/2021] [Indexed: 11/21/2022] Open
Abstract
A novel fluorescence (FL) imaging platform was established for ultrasensitive and rapid detection of cardiac troponin T (cTnT), based on a high-throughput immunosensor chip and a DNA dendrimer capped with a large number of fluorescent dyes (FDD@Cy5). Through an enzyme-free and step-by-step strategy, FDD@Cy5 was self-assembled facilely. After the formation of a sandwich immunocomplex and biotin–streptavidin conjugation, FDD@Cy5 could be captured on the chip. FL signals emerged from Cy5 under external light and the enrichment of Cy5 on the dendrimer led to signal amplification. A FL image containing 90 spots could be collected instantaneously by laser confocal scanning microscopy and the brightness of all the spots corresponded to the concentrations of target cTnT. Under optimal conditions, the immunosensor chip coupled with FDD@Cy5 exhibited an excellent detection limit of 0.10 pg L−1, a wide linear range from 0.20 pg L−1 to 2.0 ng L−1, a sample consumption down to 3.0 μL and a maximum throughput of 45 tests per h. The proposed approach was also applied to cTnT quantitation in serum samples with acceptable accuracy, providing a new avenue for early diagnosis and the prognosis evaluation of acute myocardial infarction. A novel fluorescence imaging platform based on a high-throughput immunosensor chip and a DNA dendrimer capped with plenty of fluorescent dyes was proposed for ultrasensitive quantitation of cardiac troponin T.![]()
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Affiliation(s)
- Ruike Wang
- College of Pharmacy, Xinjiang Medical University Urumqi 830011 P. R. China .,State Key Laboratory of Natural Medicines, China Pharmaceutical University Nanjing 210009 P. R. China
| | - Chen Zong
- State Key Laboratory of Natural Medicines, China Pharmaceutical University Nanjing 210009 P. R. China
| | - Gairu Li
- College of Pharmacy, Xinjiang Medical University Urumqi 830011 P. R. China
| | - Junhong Wang
- Jiangsu Province Hospital, Nanjing Medical University First Affiliated Hospital Nanjing 210029 P. R. China
| | - Tiantian Kong
- Xinjiang Medical University Affiliated Second Hospital Urumqi 830063 P. R. China
| | - Fei Li
- College of Pharmacy, Xinjiang Medical University Urumqi 830011 P. R. China .,State Key Laboratory of Natural Medicines, China Pharmaceutical University Nanjing 210009 P. R. China
| | - Junmin Chang
- College of Pharmacy, Xinjiang Medical University Urumqi 830011 P. R. China
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Qiao M, Lin L, Xia K, Li J, Zhang X, Linhardt RJ. Recent advances in biotechnology for heparin and heparan sulfate analysis. Talanta 2020; 219:121270. [PMID: 32887160 PMCID: PMC7474733 DOI: 10.1016/j.talanta.2020.121270] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 05/29/2020] [Accepted: 05/30/2020] [Indexed: 01/07/2023]
Abstract
Heparan sulfate (HS) is a class of linear, sulfated, anionic polysaccharides, called glycosaminoglycans (GAGs), which present on the mammalian cell surfaces and extracellular matrix. HS GAGs display a wide range of critical biological functions, particularly in cell signaling. HS is composed of repeating units of 1 → 4 glucosidically linked uronic acid and glucosamine residues. Heparin, a pharmacologically important version of HS, having higher sulfation and a higher content of iduronic acid than HS, is a widely used clinical anticoagulant. However, due to their heterogeneity and complex structure, HS and heparin are very challenging to analyze, limiting biological studies and even resulting in safety concerns in their therapeutic application. Therefore, reliable methods of structural analysis of HS and heparin are critically needed. In addition to the structural analysis of heparin, its concentration in blood needs to be closely monitored to avoid complications such as thrombocytopenia or hemorrhage caused by heparin overdose. This review summarizes the progress in biotechnological approaches in the structural characterization of HS and heparin over the past decade and includes the development of the ultrasensitive approaches for detection and measurement in biological samples.
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Affiliation(s)
- Meng Qiao
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Wenyuan Road 1, Nanjing, 210023, China
| | - Lei Lin
- School of Environment, Nanjing Normal University, Wenyuan Road 1, Nanjing, 210023, China
| | - Ke Xia
- Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Jun Li
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Xing Zhang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Wenyuan Road 1, Nanjing, 210023, China.
| | - Robert J Linhardt
- Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA; Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
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Wang Q, DU J, Liu F. Changes of Serum Adiponectin and Glycated Albumin Levels in Gestational Diabetes Mellitus Patients and Their Relationship with Insulin Resistance. IRANIAN JOURNAL OF PUBLIC HEALTH 2020; 49:1252-1261. [PMID: 33083291 PMCID: PMC7548504 DOI: 10.18502/ijph.v49i7.3578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Background: We aimed to investigate the changes of serum adiponectin and glycated albumin (GA) levels in gestational diabetes mellitus patients and their relationship with insulin resistance. Methods: Overall, 137 pregnant women were enrolled from Jinan City People's Hospital, Laiwu District, China from Jan 2015 to Jun 2018. Among them, 71 pregnant women with gestational diabetes mellitus were examined as diabetes group, and 66 normal pregnant women as normal pregnant women group. In addition, 58 normal non-pregnant women of childbearing age who were examined in our hospital during the same period were selected as a control group. The serum adiponectin and GA levels of the three groups were compared, and the relationship between serum adiponectin, GA levels and insulin resistance was analyzed. Results: The serum adiponectin level of pregnant women in gestational diabetes mellitus (GDM) group was significantly lower than that of normal pregnant women and control group (P=0.031, P=0.027). The serum GA level of pregnant women in GDM group was significantly higher than that of normal pregnant women and control group (P<0.001). Pearson correlation analysis showed that GA was positively correlated with Fasting plasma glucose (FPG), Fasting insulin (FINS) and Insulin resistance index(HOMA-IR) levels (P<0.001), while adiponectin was negatively correlated with FPG FINS and HOMA-IR levels (P<0.001). Conclusion: Abnormal levels of serum GA and adiponectin are closely related to insulin resistance in patients with gestational diabetes mellitus. Detection of serum GA and adiponectin levels can diagnose gestational diabetes mellitus quickly and effectively.
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Affiliation(s)
- Qingju Wang
- Department of General Medicine, Jinan City People's Hospital, Jinan, China
| | - Juan DU
- Department of General Medicine, Jinan City People's Hospital, Jinan, China
| | - Fenglian Liu
- Department of General Medicine, Jinan City People's Hospital, Jinan, China
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Kim HU, Kim HY, Seok H, Kanade V, Yoo H, Park KY, Lee JH, Lee MH, Kim T. Flexible MoS2–Polyimide Electrode for Electrochemical Biosensors and Their Applications for the Highly Sensitive Quantification of Endocrine Hormones: PTH, T3, and T4. Anal Chem 2020; 92:6327-6333. [DOI: 10.1021/acs.analchem.9b05172] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Hyeong-U Kim
- Department of Materials Science and Engineering, Northwestern University, Evanston 60208, United States
| | - Hye Youn Kim
- School of Integrative Engineering, Chung-Ang University, Seoul 06973, Republic of Korea
| | | | | | - Hocheon Yoo
- Department of Electronic Engineering, Gachon University, Seongnam 13120, Republic of Korea
| | - Kyu-Young Park
- Department of Materials Science and Engineering, Northwestern University, Evanston 60208, United States
| | - Jae-Hyun Lee
- Department of Energy Systems Research and Department of Materials Science and Engineering, Ajou University, Suwon 16499, Republic of Korea
| | - Min-Ho Lee
- School of Integrative Engineering, Chung-Ang University, Seoul 06973, Republic of Korea
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Kooshki H, Abbaszadeh R, Heidari R, Akbariqomi M, Mazloumi M, Shafei S, Absalan M, Tavoosidana G. Developing a DNA aptamer-based approach for biosensing cystatin-c in serum: An alternative to antibody-based methods. Anal Biochem 2019; 584:113386. [DOI: 10.1016/j.ab.2019.113386] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 07/22/2019] [Accepted: 08/03/2019] [Indexed: 12/28/2022]
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Mattison CP, Khurana T, Tarver MR, Florane CB, Grimm CC, Pakala SB, Cottone CB, Riegel C, Bren-Mattison Y, Slater JE. Cross-reaction between Formosan termite (Coptotermes formosanus) proteins and cockroach allergens. PLoS One 2017; 12:e0182260. [PMID: 28767688 PMCID: PMC5540505 DOI: 10.1371/journal.pone.0182260] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 07/14/2017] [Indexed: 11/30/2022] Open
Abstract
Cockroach allergens can lead to serious allergy and asthma symptoms. Termites are evolutionarily related to cockroaches, cohabitate in human dwellings, and represent an increasing pest problem in the United States. The Formosan subterranean termite (Coptotermes formosanus) is one of the most common species in the southern United States. Several assays were used to determine if C. formosanus termite proteins cross-react with cockroach allergens. Expressed sequence tag and genomic sequencing results were searched for homology to cockroach allergens using BLAST 2.2.21 software. Whole termite extracts were analyzed by mass-spectrometry, immunoassay with IgG and scFv antibodies to cockroach allergens, and human IgE from serum samples of cockroach allergic patients. Expressed sequence tag and genomic sequencing results indicate greater than 60% similarity between predicted termite proteins and German and American cockroach allergens, including Bla g 2/Per a 2, Bla g 3/Per a 3, Bla g 5, Bla g 6/Per a 6, Bla g 7/Per a 7, Bla g 8, Per a 9, and Per a 10. Peptides from whole termite extract were matched to those of the tropomyosin (Bla g 7), arginine kinase (Per a 9), and myosin (Bla g 8) cockroach allergens by mass-spectrometry. Immunoblot and ELISA testing revealed cross-reaction between several proteins with IgG and IgE antibodies to cockroach allergens. Several termite proteins, including the hemocyanin and tropomyosin orthologs of Blag 3 and Bla g 7, were shown to crossreact with cockroach allergens. This work presents support for the hypothesis that termite proteins may act as allergens and the findings could be applied to future allergen characterization, epitope analysis, and clinical studies.
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Affiliation(s)
- Christopher P. Mattison
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, New Orleans, Louisiana, United States of America
| | - Taruna Khurana
- Division of Vaccines and Related Products Applications, United States Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Matthew R. Tarver
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, New Orleans, Louisiana, United States of America
| | - Christopher B. Florane
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, New Orleans, Louisiana, United States of America
| | - Casey C. Grimm
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, New Orleans, Louisiana, United States of America
| | - Suman B. Pakala
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Carrie B. Cottone
- New Orleans Mosquito, Termite and Rodent Control Board, New Orleans, Louisiana, United States of America
| | - Claudia Riegel
- New Orleans Mosquito, Termite and Rodent Control Board, New Orleans, Louisiana, United States of America
| | | | - Jay E. Slater
- Division of Bacterial, Parasitic and Allergenic Products, United States Food and Drug Administration, Silver Spring, Maryland, United States of America
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Abstract
Food allergy is a public health concern especially after recognizing its constantly increased prevalence and severity. Despite careful reading of food ingredient statements, food allergic individuals may experience reactions caused by "hidden", "masked", or "contaminated" proteins that are known major allergens. Many techniques have been developed to detect even small traces of food allergens, for clinical or laboratory purposes. Enzyme-linked immunosorbent assay (ELISA) is one of the best validated and most routinely used immunoassay in allergy research, in allergy diagnosis in allergy-related quality control in various industries. Although as a technique it has been implemented for the last 45 years, the evolution in biochemistry allowed the development of ultrasensitive ELISA variations that are capable of measuring quantities in the scale of picograms, rendering ELISA attractive, robust, and very famous.
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Affiliation(s)
- George N Konstantinou
- Department of Allergy and Clinical Immunology, 424 General Military Training Hospital, 11 Eleftheriou Venizelou Street, Kalamaria, 55 133, Thessaloniki, Greece.
- Division of Allergy and Immunology, Jaffe Food Allergy Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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Yi SY, Lee U, Chung BH, Jung J. A scanometric antibody probe for facile and sensitive immunoassays. Chem Commun (Camb) 2016; 51:8865-7. [PMID: 25926018 DOI: 10.1039/c5cc02838h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We have developed a novel scanometric antibody probe for rapid, sensitive, and naked-eye-visible immunoassays. Using this probe, we clearly demonstrated the successful scanometric detection and identification of influenza A viruses on a microarray. In addition, the sensitivity of the scanometric immunoassay was comparable to that of the fluorescence-based method.
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Affiliation(s)
- So Yeon Yi
- BioNanotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, 305-806, Daejeon, Republic of Korea.
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Khurana T, Dobrovolskaia E, Shartouny JR, Slater JE. Multiplex Assay for Protein Profiling and Potency Measurement of German Cockroach Allergen Extracts. PLoS One 2015; 10:e0140225. [PMID: 26444288 PMCID: PMC4596881 DOI: 10.1371/journal.pone.0140225] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/22/2015] [Indexed: 11/22/2022] Open
Abstract
Background German cockroach (GCr) allergens induce IgE responses and may cause asthma. Commercial GCr allergen extracts are variable and existing assays may not be appropriate for determining extract composition and potency. Objective Our aim was to develop a multiplex antibody/bead-based assay for assessment of GCr allergen extracts. Methods Single chain fragment variable (scFv) antibodies against GCr were obtained by screening libraries derived from naïve human lymphocytes and hyperimmunized chicken splenocytes and bone marrow. Selected clones were sequenced and characterized by immunoblotting. Eighteen scFv antibodies (17 chicken, 1 human) coupled to polystyrene beads were used in this suspension assay; binding of targeted GCr allergens to antibody-coated beads was detected using rabbit antisera against GCr, and against specific allergens rBla g 1, rBla g 2, and rBla g 4. The assay was tested for specificity, accuracy, and precision. Extracts were also compared by IgE competition ELISA. Results Chicken scFv’s generated eight different binding patterns to GCr proteins from 14 to 150 kDa molecular weight. Human scFv’s recognized a 100 kDa GCr protein. The multiplex assay was found to be specific and reproducible with intra-assay coefficient of variation (CV) of 2.64% and inter-assay CV of 10.0%. Overall potencies of various GCr extracts were calculated using mean logEC50s for eight selected scFvs. Overall potency measures were also analyzed by assessing the contributions to potency of each target. Conclusions An scFv antibody-based multiplex assay has been developed capable of simultaneously measuring different proteins in a complex mixture, and to determine the potencies and compositions of allergen extracts.
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Affiliation(s)
- Taruna Khurana
- Laboratory of Immunobiochemistry, Division of Bacterial, Parasitic and Allergenic Products, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Ekaterina Dobrovolskaia
- Laboratory of Immunobiochemistry, Division of Bacterial, Parasitic and Allergenic Products, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Jessica R. Shartouny
- Laboratory of Immunobiochemistry, Division of Bacterial, Parasitic and Allergenic Products, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Jay E. Slater
- Laboratory of Immunobiochemistry, Division of Bacterial, Parasitic and Allergenic Products, US Food and Drug Administration, Silver Spring, Maryland, United States of America
- * E-mail:
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Chen A, Wang R, Bever CRS, Xing S, Hammock BD, Pan T. Smartphone-interfaced lab-on-a-chip devices for field-deployable enzyme-linked immunosorbent assay. BIOMICROFLUIDICS 2014; 8:064101. [PMID: 25553178 PMCID: PMC4241779 DOI: 10.1063/1.4901348] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Accepted: 10/30/2014] [Indexed: 05/09/2023]
Abstract
The emerging technologies on mobile-based diagnosis and bioanalytical detection have enabled powerful laboratory assays such as enzyme-linked immunosorbent assay (ELISA) to be conducted in field-use lab-on-a-chip devices. In this paper, we present a low-cost universal serial bus (USB)-interfaced mobile platform to perform microfluidic ELISA operations in detecting the presence and concentrations of BDE-47 (2,2',4,4'-tetrabromodiphenyl ether), an environmental contaminant found in our food supply with adverse health impact. Our point-of-care diagnostic device utilizes flexible interdigitated carbon black electrodes to convert electric current into a microfluidic pump via gas bubble expansion during electrolytic reaction. The micropump receives power from a mobile phone and transports BDE-47 analytes through the microfluidic device conducting competitive ELISA. Using variable domain of heavy chain antibodies (commonly referred to as single domain antibodies or Nanobodies), the proposed device is sensitive for a BDE-47 concentration range of 10(-3)-10(4 ) μg/l, with a comparable performance to that uses a standard competitive ELISA protocol. It is anticipated that the potential impact in mobile detection of health and environmental contaminants will prove beneficial to our community and low-resource environments.
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Affiliation(s)
- Arnold Chen
- Department of Biomedical Engineering, University of California , Davis, California 95616, USA
| | - Royal Wang
- Department of Biomedical Engineering, University of California , Davis, California 95616, USA
| | - Candace R S Bever
- Department of Entomology and Nematology, University of California , Davis, California 95616, USA
| | - Siyuan Xing
- Department of Biomedical Engineering, University of California , Davis, California 95616, USA
| | | | - Tingrui Pan
- Department of Biomedical Engineering, University of California , Davis, California 95616, USA
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Al Ahmad M, Mustafa F, Ali LM, Rizvi TA. Virus detection and quantification using electrical parameters. Sci Rep 2014; 4:6831. [PMID: 25355078 PMCID: PMC4213776 DOI: 10.1038/srep06831] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 10/06/2014] [Indexed: 01/31/2023] Open
Abstract
Here we identify and quantitate two similar viruses, human and feline immunodeficiency viruses (HIV and FIV), suspended in a liquid medium without labeling, using a semiconductor technique. The virus count was estimated by calculating the impurities inside a defined volume by observing the change in electrical parameters. Empirically, the virus count was similar to the absolute value of the ratio of the change of the virus suspension dopant concentration relative to the mock dopant over the change in virus suspension Debye volume relative to mock Debye volume. The virus type was identified by constructing a concentration-mobility relationship which is unique for each kind of virus, allowing for a fast (within minutes) and label-free virus quantification and identification. For validation, the HIV and FIV virus preparations were further quantified by a biochemical technique and the results obtained by both approaches corroborated well. We further demonstrate that the electrical technique could be applied to accurately measure and characterize silica nanoparticles that resemble the virus particles in size. Based on these results, we anticipate our present approach to be a starting point towards establishing the foundation for label-free electrical-based identification and quantification of an unlimited number of viruses and other nano-sized particles.
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Affiliation(s)
- Mahmoud Al Ahmad
- Department of Electrical Engineering, College of Engineering, United Arab Emirates University, Al Ain, UAE
| | - Farah Mustafa
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, UAE
| | - Lizna M Ali
- Department of Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, UAE
| | - Tahir A Rizvi
- Department of Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, UAE
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Bla g 3: a novel allergen of German cockroach identified using cockroach-specific avian single-chain variable fragment antibody. Ann Allergy Asthma Immunol 2013; 112:140-145.e1. [PMID: 24468254 DOI: 10.1016/j.anai.2013.11.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 10/30/2013] [Accepted: 11/03/2013] [Indexed: 11/22/2022]
Abstract
BACKGROUND The IgE response to cockroach allergens is thought to be associated with asthma. German cockroach (GCr) allergen extract is a complex mixture of allergens, and the identification and characterization of immunodominant allergens is important for the effective diagnosis and treatment of GCr-induced asthma. OBJECTIVE To characterize a novel GCr allergen homologous to the American cockroach allergen Per a 3. METHODS GCr-specific avian monoclonal antibodies were used for direct immunoprecipitation of specific targets from whole-body GCr extract. Precipitated protein was identified by mass spectrometry and sequence analysis. Putative recombinant protein also was expressed, purified, and used for determination of allergenicity, determined by IgE enzyme-linked immunosorbent assay with serum from 61 GCr-allergic patients. The identified target also was analyzed for heat stability using a bead-based assay. RESULTS The immunoprecipitated target of monoclonal antibody 2A1 was identified as a novel allergen of GCr homologous to American cockroach allergen Per a 3. This homolog, designated Bla g 3, has an apparent mass of 78 kDa, can be measured in GCr extract using antibody 2A1, and is a heat-stable protein. Screening of 61 serum samples from GCr-allergic patients showed a 22% prevalence of Bla g 3-specific IgE. CONCLUSION Bla g 3 is a GCr allergen with structural homology to American cockroach allergen Per a 3.
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Hu CQ, Chen HB, Gao JY, Luo CP, Ma XJ, Tong P. High-pressure microfluidisation-induced changes in the antigenicity and conformation of allergen Ara h 2 purified from Chinese peanut. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2011; 91:1304-1309. [PMID: 21384372 DOI: 10.1002/jsfa.4318] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 12/16/2010] [Accepted: 12/16/2010] [Indexed: 05/30/2023]
Abstract
BACKGROUND Peanut allergy is one of the most serious food allergies, and Ara h 2 is one of the most important peanut allergens as it is recognised by serum immunoglobulin E from more than 90% of peanut-allergic individuals. Dynamic high-pressure microfluidisation has been widely used in food processing as a new technology. The aim of this study was to investigate the effect of high-pressure microfluidisation on the antigenicity and structure of Ara h 2. Extracted peanut allergen Ara h 2 was treated under a continuous pressure array of 60, 90, 120, 150 and 180 MPa. Immunoreactivity was measured by indirect enzyme-linked immunosorbent assay with rabbit polyclonal antibodies. Secondary structure was analysed by circular dichroism. Surface hydrophobicity and sulfhydryl groups were assessed via fluorescence and UV absorption spectra respectively. RESULTS High-pressure microfluidisation treatment decreased the antigenicity of peanut allergen Ara h 2, changed its secondary structure and increased its UV absorption intensity and surface hydrophobicity. CONCLUSION The change in conformation contributed to the decrease in antigenicity of Ara h 2, and the spatial conformation of peanut allergen Ara h 2 plays a critical role in its antigenicity.
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Affiliation(s)
- Chun-qiu Hu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China
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deVore NC, Huynh S, Dobrovolskaia EN, Slater JE. Multiplex microbead measurements for the characterization of cat and ragweed allergen extracts. Ann Allergy Asthma Immunol 2011; 105:351-8. [PMID: 21055660 DOI: 10.1016/j.anai.2010.09.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 08/27/2010] [Accepted: 09/26/2010] [Indexed: 10/18/2022]
Abstract
BACKGROUND Current assays for allergen extracts can measure either overall potency or the levels of individual allergens. OBJECTIVE To develop a multiplex allergen extract potency assay (MAEPA) for allergen extracts that can concurrently measure individual allergens and characterize the overall allergen levels in the mixture. METHODS Six anti-Fel d 1 and 6 anti-Amb a 1 recombinant antibodies were generated and were covalently bound to carboxy-labeled beads. Antibody-bound beads were then used to measure Fel d 1 and Amb a 1 levels in commercial cat hair and short ragweed pollen (SRP) extracts, respectively, using bead-based flow cytometry. These major allergen levels were compared with those obtained using a conventional antibody-based method. Allergen levels were calculated by comparing the half-maximal effective concentrations of dose-response curves analyzed using 4-parameter fits. Bead-antibody pairs were tested to determine whether the presence of additional bead-antibody pairs affected the apparent potency of the extract. RESULTS Allergen contents of cat hair and SRP extracts determined using the MAEPA and anti-Fel d 1 and anti-Amb a 1 antibodies were comparable with potencies determined using conventional methods. Cross-interference from the concurrent use of multiple beads was minimal. Six lots of cat hair extract and 6 lots of SRP extract were tested. CONCLUSIONS The MAEPA, a bead-based assay using recombinant antibodies, accurately determined Fel d 1 levels in cat hair allergenic extracts and Amb a 1 levels in SRP extracts. The results of this assay are reproducible and are consistent with data obtained using conventional methods.
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Affiliation(s)
- Nicolette C deVore
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda, Maryland, USA
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Abstract
The development of reliable and clinically relevant potency assays is essential to the practice of safe and effective allergen-specific immunotherapy. Allergen standardization in the United States is based on the establishment of a national reference assigned with a biological potency unit to which manufacturers' products are compared using validated relative potency assays. This ensures, at least with standardized allergen vaccines, comparability between lots used in clinical practice. Recent progress in the ability to measure the specific allergen content of allergen vaccines has led to its application in monitoring consistency and characterizing allergen preparations. More recently, the "major allergen" content of allergen vaccines has become a means to compare extracts from different manufacturers and to recommend immunotherapy dosing regimens. At the same time, qualitative differences exist between manufacturers' products, and most allergen vaccines used in clinical practice are nonstandardized. Therefore, this approach can be confusing and is misleading. The establishment of additional allergen reference standards and the development of reliable, accurate, and clinically relevant potency assays are urgently needed.
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Affiliation(s)
- Robert E Esch
- Greer Laboratories, 639 Nuway Circle, Lenoir, NC 28645, USA.
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