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Luo Y, Liu X, Jiang T, Liao P, Fu W. Dual-aptamer-based biosensing of toxoplasma antibody. Anal Chem 2013; 85:8354-60. [PMID: 23899133 DOI: 10.1021/ac401755s] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A panel of seven aptamers to antitoxoplasma IgG is first discovered in this report. The aptamers are selected using systematic evolution of ligands by exponential enrichment (SELEX) technology, cloned, and identified by sequencing and affinity assay. Among them, two aptamers (TGA6 and TGA7) with the highest affinities are employed as capture probe and detection probe in developing a quantum dots-labeled dual aptasensor (Q-DAS). In the presence of antitoxoplasma IgG, an aptamer-protein-aptamer sandwich complex (TGA6-IgG-TGA7) is formed and captured on a multiwell microplate, whose fluorescence can be read out using quantum dots as the fluorescence label, ensuring highly sensitive and specific sensing of antitoxoplasma IgG. The operating characteristics of the proposed assay are guaranteed using dual aptamers as the recognizing probes when compared with antibody-based immunoassay. Q-DAS has a linearity within the range of 0.5-500 IU with a lowest detection of 0.1 IU. Receiver operating curves of 212 clinical samples show a 94.8% sensitivity and 95.7% specificity when the cutoff value is set as 6.5 IU, indicating the proposed Q-DAS is a promising assay in large-scale screening of toxoplasmosis.
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Affiliation(s)
- Yang Luo
- Department of Laboratory Medicine, Southwest Hospital, the Third Military Medical University, Chong Qing 400038, China
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Wiklund M, Nord O, Gothäll R, Chernyshev AV, Nygren PA, Hertz HM. Fluorescence-microscopy-based image analysis for analyte-dependent particle doublet detection in a single-step immunoagglutination assay. Anal Biochem 2005; 338:90-101. [PMID: 15707939 DOI: 10.1016/j.ab.2004.11.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2004] [Indexed: 10/26/2022]
Abstract
A novel fluorescence-microscopy-based image analysis method for classification of singlet and doublet latex particles is demonstrated and applied to a particle-based immunoagglutination assay for quantification of biomolecules in microliter-volume bulk samples. The image analysis method, verified by flow cytometric agglutination analysis, is based on a pattern recognition algorithm employing Gaussian-base-function fitting which allows robust identification and counting of singlets, doublets, and higher agglomerates of fluorescent microparticles. The immunoagglutination assay is experimentally modeled by a biotin-streptavidin interaction, with the goal of both theoretically and experimentally investigating the performance of a general immunoagglutination-based assay. For this purpose a theoretical model of the initial agglutination kinetics, based on particle diffusion combined with a steric factor determined by the level of specific and nonspecific agglutination, was developed. The theoretical model combined with the experimental data can be used to optimize an agglutination-based assay with regard to sensitivity and dynamic range and to estimate the affinity, receptor surface density, molecular and binding site sizes, and level of nonspecific binding that is present in the assay. The experimental results are in good agreement with the theoretical model, indicating the usefulness of the model for immunoagglutination assay optimization.
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Affiliation(s)
- Martin Wiklund
- Biomedical and X-Ray Physics, Royal Institute of Technology, AlbaNova University Center, SE-106 91 Stockholm, Sweden.
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Kudo T, Kido A, Nishiyama Y, Koganeya H, Okuda T, Nabeshima M, Iinuma Y, Ichiyama S. Whole-Blood Counting Immunoassay as a Short-Turnaround Test for Detection of Hepatitis B Surface Antigen, Anti-Hepatitis C Virus Antibodies, and Anti-
Treponema pallidum
Antibodies. J Clin Microbiol 2004; 42:4250-2. [PMID: 15365019 PMCID: PMC516346 DOI: 10.1128/jcm.42.9.4250-4252.2004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ABSTRACT
Whole-blood samples were used for a counting immunoassay (CIA) with the aim of developing a short- turnaround test. After optimization of the CIA, hepatitis B surface antigen (HBsAg), anti-hepatitis C virus antibodies (anti-HCV), and anti-
Treponema pallidum
antibodies (anti-TP) were detected as efficiently as by an enzyme immunoassay (EIA) with serum samples. The correlations between whole-blood CIA and serum EIA were 99.8, 97.1, and 99.4% for HBsAg, anti-HCV, and anti-TP, respectively. Whole-blood CIA may be of value when rapid screening of many samples is required.
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Affiliation(s)
- Toyoichiro Kudo
- Deaprtment of Laboratory Medicine, Graduate School of Medicine, Kyoto University Hospital, 54 Kawahara Shogoin, Sakyoku, Kyoto 606-8507, Japan.
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Markine-Goriaynoff D, Hulhoven X, Cambiaso CL, Monteyne P, Briet T, Gonzalez MD, Coulie P, Coutelier JP. Natural killer cell activation after infection with lactate dehydrogenase-elevating virus. J Gen Virol 2002; 83:2709-2716. [PMID: 12388806 DOI: 10.1099/0022-1317-83-11-2709] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Early after infection, lactate dehydrogenase-elevating virus (LDV) alters the immune system by polyclonally activating B lymphocytes, which leads to IgG2a-restricted hypergammaglobulinaemia, and by suppressing the secretion of Th2 cytokines. Considering that these alterations may involve cells of the innate immune system and cytokines such as interferon-gamma (IFN-gamma), we analysed the effect of LDV on natural killer (NK) cells. Within a few days of infection, a strong and transient NK cell activation, characterized by enhanced IFN-gamma message expression and cytolysis, was observed. LDV triggered a large increase in serum IFN-gamma levels. Because NK cells and IFN-gamma may participate in the defence against virus infection, we analysed their possible role in the control of LDV titres with a new agglutination assay. Our results indicate that neither the activation of NK cells nor the IFN-gamma secretion affect the early and rapid virus replication that follows LDV inoculation.
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Affiliation(s)
- Dominique Markine-Goriaynoff
- Unit of Experimental Medicine1 and Unit of Cellular Genetics2, Institute for Cellular Pathology, Université Catholique de Louvain, UCL MEXP 7430, Av. Hippocrate 74, 1200 Bruxelles, Belgium
| | - Xavier Hulhoven
- Unit of Experimental Medicine1 and Unit of Cellular Genetics2, Institute for Cellular Pathology, Université Catholique de Louvain, UCL MEXP 7430, Av. Hippocrate 74, 1200 Bruxelles, Belgium
| | - César L Cambiaso
- Unit of Experimental Medicine1 and Unit of Cellular Genetics2, Institute for Cellular Pathology, Université Catholique de Louvain, UCL MEXP 7430, Av. Hippocrate 74, 1200 Bruxelles, Belgium
| | - Philippe Monteyne
- Unit of Experimental Medicine1 and Unit of Cellular Genetics2, Institute for Cellular Pathology, Université Catholique de Louvain, UCL MEXP 7430, Av. Hippocrate 74, 1200 Bruxelles, Belgium
| | - Thérèse Briet
- Unit of Experimental Medicine1 and Unit of Cellular Genetics2, Institute for Cellular Pathology, Université Catholique de Louvain, UCL MEXP 7430, Av. Hippocrate 74, 1200 Bruxelles, Belgium
| | - Maria-Dolores Gonzalez
- Unit of Experimental Medicine1 and Unit of Cellular Genetics2, Institute for Cellular Pathology, Université Catholique de Louvain, UCL MEXP 7430, Av. Hippocrate 74, 1200 Bruxelles, Belgium
| | - Pierre Coulie
- Unit of Experimental Medicine1 and Unit of Cellular Genetics2, Institute for Cellular Pathology, Université Catholique de Louvain, UCL MEXP 7430, Av. Hippocrate 74, 1200 Bruxelles, Belgium
| | - Jean-Paul Coutelier
- Unit of Experimental Medicine1 and Unit of Cellular Genetics2, Institute for Cellular Pathology, Université Catholique de Louvain, UCL MEXP 7430, Av. Hippocrate 74, 1200 Bruxelles, Belgium
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Singh AK. Evaluation of solid-phase chemiluminescent enzyme immunoassay, enzyme-linked immunosorbent assay, and latex agglutination tests for screening toxoplasma IgG in samples obtained from cats and pigs. J Vet Diagn Invest 2000; 12:136-41. [PMID: 10730942 DOI: 10.1177/104063870001200206] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Serum samples from cats and pigs were analyzed by the solid-phase chemiluminescent enzyme immunoassay (SPCEI), enzyme-linked immunosorbent assay (ELISA), and indirect latex agglutination (ILA) methods. The SPCEI and ILA methods accurately analyzed Toxoplasma IgG (T-IgG) in both clinical and spiked samples from pigs and cats. The ELISA method accurately analyzed T-IgG in spiked samples from cats and pigs or clinical samples from pigs, but it did not accurately analyze T-IgG in clinical samples from cats. The antibody used in the ELISA kit did not cross-react with cat T-IgG. The SPCEI method that uses a stand-alone automated analyzer provided quantitative analysis, whereas the ELISA and ILA methods provided qualitative or, at best, semiquantitative analysis of T-IgG. The SPCEI and ELISA methods were rapid (60-90 minutes for 30 samples), whereas the ILA method required 13-15 hours for 30 samples. Although the three methods accurately distinguished positive from negative samples, the ILA method yielded many weakly positive results that were not confirmed by either the ELISA or SPCEI method. Thus, the indirect agglutination tests may give nonspecific responses at lower T-IgG concentrations.
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Affiliation(s)
- A K Singh
- Minnesota Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul 55108, USA
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