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Liu S, Song D, Bai H, Lu W, Dai X, Hao C, Zhang Z, Guo H, Zhang Y, Li X. A safe and reliable neutralization assay based on pseudovirus to measure neutralizing antibody titer against poliovirus. J Med Virol 2017; 89:2075-2083. [PMID: 28786502 DOI: 10.1002/jmv.24909] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 07/01/2017] [Indexed: 12/11/2022]
Abstract
With the promotion of inactivated poliomyelitis vaccine (IPV) and live attenuated oral poliomyelitis vaccine (OPV), the global reported cases of poliomyelitis have reduced sharply from 0.35 million in 1988 to 74 in 2015. The Polio Eradication & Endgame Strategic Plan published by WHO in 2013 included the strategy of implementation of poliovirus safe handling and containment measures to minimize the risks of facility-associated reintroduction of virus into the polio-free community to prevent the re-import of poliovirus. Toward this strategy, we produced replication-incompetent pseudovirus of poliovirus type 1, 2, 3 attenuated strains by constructing poliovirus capsid expression vectors and poliovirus replicon then transfecting HEK293T cells and developed a pseudovirus-based neutralization assay (pNA) to determine neutralizing antibody titer which is more secure, time-saving and reliable than conventional neutralization assay (cNA). By using anti-poliovirus rat serum, we demonstrated excellent correlation between neutralizing antibody titers measured by cNA and pNA. It was concluded that pNA can be a potential alternative to replace cNA as a safe and time-saving system for titer determination after live poliovirus's safekeeping.
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Affiliation(s)
- Shaohua Liu
- National Vaccine and Serum Institute, Beijing, China
| | - Dongmei Song
- National Vaccine and Serum Institute, Beijing, China
| | - Han Bai
- National Vaccine and Serum Institute, Beijing, China
| | - Weiwei Lu
- National Vaccine and Serum Institute, Beijing, China
| | - Xinxian Dai
- National Vaccine and Serum Institute, Beijing, China
| | - Chunsheng Hao
- National Vaccine and Serum Institute, Beijing, China
| | | | - Huijie Guo
- National Vaccine and Serum Institute, Beijing, China
| | - Yue Zhang
- National Vaccine and Serum Institute, Beijing, China
| | - Xiuling Li
- National Vaccine and Serum Institute, Beijing, China
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Abstract
High-throughput screening (HTS) is a key process used in drug discovery to identify hits from compound libraries that may become leads for medicinal chemistry optimization. This updated overview discusses the utilization of compound libraries, compounds derived from combinatorial and parallel synthesis campaigns and natural product sources; creation of mother and daughter plates; and compound storage, handling, and bar coding in HTS. The unit also presents an overview of established and emerging assay technologies (i.e., time-resolved fluorescence, fluorescence polarization, fluorescence-correlation spectroscopy, functional whole cell assays, and high-content assays) and their integration in automation hardware and IT systems. This revised unit provides updated descriptions of state-of-the-art instrumentation and technologies in this rapidly changing environment. The section on assay methodologies now also covers enzyme complementation assays and methods for high-throughput screening of ion channel activities. Finally, a section on criteria for assay robustness is included discussing the Z'-factor, which is now a widely accepted criterion for evaluation and validation of high throughput screening assays.
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Affiliation(s)
- Michael Entzeroth
- Experimental Therapeutics Centre, Agency for Science, Technology, and Research (A*STAR), Singapore
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Applications of molecular imaging. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 95:237-98. [PMID: 21075334 DOI: 10.1016/b978-0-12-385071-3.00009-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Today molecular imaging technologies play a central role in clinical oncology. The use of imaging techniques in early cancer detection, treatment response, and new therapy development is steadily growing and has already significantly impacted on clinical management of cancer. In this chapter, we overview three different molecular imaging technologies used for the understanding of disease biomarkers, drug development, or monitoring therapeutic outcome. They are (1) optical imaging (bioluminescence and fluorescence imaging), (2) magnetic resonance imaging (MRI), and (3) nuclear imaging (e.g., single-photon emission computed tomography (SPECT) and positron emission tomography (PET)). We review the use of molecular reporters of biological processes (e.g., apoptosis and protein kinase activity) for high-throughput drug screening and new cancer therapies, diffusion MRI as a biomarker for early treatment response and PET and SPECT radioligands in oncology.
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Bukh AS, Roslev P. Characterization and validation of a chemiluminescent assay based on a 1,2-dioxetane for rapid detection of enterococci in contaminated water and comparison with standard methods and qPCR. J Appl Microbiol 2011; 111:407-16. [PMID: 21575110 DOI: 10.1111/j.1365-2672.2011.05051.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To evaluate the potential for using a novel chemiluminescence-based enzyme assay for rapid detection of enterococci in water contaminated with faecal waste. METHODS AND RESULTS The novel assay (EntLight) was based on the enzymatic hydrolysis of the chemiluminescent 1,2-dioxetane [(4-methoxy-4(3-β-d-glucoside-4-chlorophenyl)]spiro[1,2-dioxetane-3-1,3-tricyclo[7·3·1·0(2,7) ]tridec-2,7-ene] specific for β-d-glucosidase. The specificity of the proposed EntLight assay was characterized using 26 different Enterococcus strains and 10 bacterial genera other than Enterococcus. With an analysis time of ≤8 h, the assay was found to be sensitive and specific. Validation experiments were carried out using water samples contaminated with raw municipal wastewater in comparison with qPCR and ISO standard methods. EntLight was successfully applied to detect enterococci in contaminated water within ≤8 h, and the proposed assay correlated well with both qPCR and ISO standard methods (R(2) > 0·776). CONCLUSIONS EntLight can be applied to rapid and simple detection of viable enterococci in water contaminated with faecal matter. SIGNIFICANCE AND IMPACT OF THE STUDY The novel EntLight assay and qPCR have the potential to be used as methods for early warning (1-7 h) of faecal pollutions in different water types.
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Affiliation(s)
- A S Bukh
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Aalborg, Denmark
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Garcia JM, Lai JCC. Production of influenza pseudotyped lentiviral particles and their use in influenza research and diagnosis: an update. Expert Rev Anti Infect Ther 2011; 9:443-55. [PMID: 21504401 DOI: 10.1586/eri.11.25] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Pseudotyped viral particles are being used as safe surrogates to mimic the structure and surface of many viruses, including highly pathogenic viruses such as avian influenza H5N1, to investigate biological functions mediated by the envelope proteins derived from these viruses. The first part of this article evaluates and discusses the differences in the production and characterization of influenza pseudoparticles. The second part focuses on the applications that such a flexible tool can provide in modern influenza research, in particular in the fields of drug discovery, molecular biology and diagnosis.
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Affiliation(s)
- Jean-Michel Garcia
- HKU-Pasteur Research Centre, Dexter HC Man Building, 8 Sassoon Road, Pokfulam, Hong Kong.
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Liu L, Mason RP. Imaging beta-galactosidase activity in human tumor xenografts and transgenic mice using a chemiluminescent substrate. PLoS One 2010; 5:e12024. [PMID: 20700459 PMCID: PMC2917367 DOI: 10.1371/journal.pone.0012024] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Accepted: 06/29/2010] [Indexed: 01/04/2023] Open
Abstract
Background Detection of enzyme activity or transgene expression offers potential insight into developmental biology, disease progression, and potentially personalized medicine. Historically, the lacZ gene encoding the enzyme β-galactosidase has been the most common reporter gene and many chromogenic and fluorogenic substrates are well established, but limited to histology or in vitro assays. We now present a novel approach for in vivo detection of β-galactosidase using optical imaging to detect light emission following administration of the chemiluminescent 1,2-dioxetane substrate Galacto-Light PlusTM. Methodology and Principal Findings B-gal activity was visualized in stably transfected human MCF7-lacZ tumors growing in mice. LacZ tumors were identified versus contralateral wild type tumors as controls, based on two- to tenfold greater light emission following direct intra tumoral or intravenous administration of reporter substrate. The 1,2-dioxetane substrate is commercially available as a kit for microplate-based assays for β-gal detection, and we have adapted it for in vivo application. Typically, 100 µl substrate mixture was administered intravenously and light emission was detected from the lacZ tumor immediately with gradual decrease over the next 20 mins. Imaging was also undertaken in transgenic ROSA26 mice following subcutaneous or intravenous injection of substrate mixture. Conclusion and Significance Light emission was detectable using standard instrumentation designed for more traditional bioluminescent imaging. Use of 1,2-dioxetane substrates to detect enzyme activity offers a new paradigm for non-invasive biochemistry in vivo.
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Affiliation(s)
- Li Liu
- Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Ralph P. Mason
- Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- * E-mail:
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Bukh AS, Roslev P. Characterization and validation of a chemiluminescent assay based on 1,2-dioxetanes for rapid detection of viable Escherichia coli. Appl Microbiol Biotechnol 2010; 86:1947-57. [DOI: 10.1007/s00253-010-2514-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Revised: 02/16/2010] [Accepted: 02/16/2010] [Indexed: 12/19/2022]
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Garcia JM, Gao A, He PL, Choi J, Tang W, Bruzzone R, Schwartz O, Naya H, Nan FJ, Li J, Altmeyer R, Zuo JP. High-throughput screening using pseudotyped lentiviral particles: a strategy for the identification of HIV-1 inhibitors in a cell-based assay. Antiviral Res 2008; 81:239-47. [PMID: 19118579 DOI: 10.1016/j.antiviral.2008.12.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 11/27/2008] [Accepted: 12/01/2008] [Indexed: 10/21/2022]
Abstract
Two decades after its discovery the human immunodeficiency virus (HIV) is still spreading worldwide and killing millions. There are 25 drugs formally approved for HIV currently on the market, but side effects as well as the emergence of HIV strains showing single or multiple resistances to current drug-therapy are causes for concern. Furthermore, these drugs target only 4 steps of the viral cycle, hence the urgent need for new drugs and also new targets. In order to tackle this problem, we have devised a cell-based assay using lentiviral particles to look for post-entry inhibitors of HIV-1. We report here the assay development, validation as well as confirmation of the hits using both wild-type and drug-resistant HIV-1 viruses. The screening was performed on an original library, rich in natural compounds and pure molecules from Traditional Chinese Medicine pharmacopoeia, which had never been screened for anti-HIV activity. The identified hits belong to four chemical sub-families that appear to be all non-nucleoside reverse transcriptase inhibitors (NNRTIs). Secondary tests with live viruses showed that there was good agreement with pseudotyped particles, confirming the validity of this approach for high-throughput drug screens. This assay will be a useful tool that can be easily adapted to screen for inhibitors of viral entry.
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Yu JX, Kodibagkar VD, Liu L, Mason RP. A 19F-NMR approach using reporter molecule pairs to assess beta-galactosidase in human xenograft tumors in vivo. NMR IN BIOMEDICINE 2008; 21:704-12. [PMID: 18288788 PMCID: PMC3044929 DOI: 10.1002/nbm.1244] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Gene therapy has emerged as a promising strategy for treatment of various diseases. However, widespread implementation is hampered by difficulties in assessing the success of transfection in the target tissue and the longevity of gene expression. Thus, there is increasing interest in the development of non-invasive in vivo reporter techniques to assay gene expression. We recently demonstrated the ability to detect beta-galactosidase activity in stably transfected human prostate tumor xenografts in mice in vivo using 19F NMR. We now extend the studies to human MCF7 breast cancer cells growing as xenografts in nude mice. Moreover, by using two spectrally resolved reporters (o-fluoro-p-nitrophenyl-beta-D-galactopyranoside and an isomer), two tumors could be interrogated simultaneously revealing lacZ transgene activity in a stably transfected tumor versus no activity in a wild-type tumor. Most significantly, hydrolytic activity observed by 19F NMR corresponded to differential activity in lacZ-expressing tumors.
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Affiliation(s)
- Jian-Xin Yu
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9058, USA
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Festoff BW, Suo Z, Citron BA. Prospects for the pharmacotherapy of amyotrophic lateral sclerosis : old strategies and new paradigms for the third millennium. CNS Drugs 2003; 17:699-717. [PMID: 12873154 DOI: 10.2165/00023210-200317100-00002] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Biomedical researchers interested in amyotrophic lateral sclerosis (ALS) must invoke newly developing technologies if we are to discover pharmaceutical treatments that will help a significant population of patients with the disease. The focus of ALS research over the last 10 years has been on reactive oxygen species (ROS) and glutamate excitotoxicity, resulting in several clinical trials and the launch of the only drug currently available for the treatment of ALS, riluzole. Unfortunately, the therapeutic benefits have been minimal, at best, and the prognosis for patients with ALS has not improved beyond very modest retardation of the disease course. By emphasising ROS and glutamate excitotoxicity, current ALS research has only partially been able to attenuate the rate of motor decline and neuronal loss associated with this illness. Clues to additional therapeutic potentialities will come from an increased understanding of the mode of cell death (apoptotic or other) and the pathways leading to neuronal demise. If death is apoptotic, inhibiting caspases may be useful. The regulatory modifications for cell death at the molecular level remain to be determined and exploited to prevent neuronal loss, although novel pathways have been recently elucidated that impact on protein aggregation and processing. Oxidative stress, seen in both familial and sporadic forms of ALS, may be only one post-translational mechanism likely to affect specific proteins essential for the health and stability of motor neurons. Protein cross-linking by transglutaminase paralleling that may lead to defects in proteasome function may also be a significant mechanism. The latest capabilities to screen protein changes in specific cells represent the kinds of advances needed to combat ALS in the third millennium.
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Affiliation(s)
- Barry W Festoff
- Department of Veterans Affairs Medical Center, Heartland Veterans Integrated Service Network, Kansas City, Missouri 64128, USA.
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McCaffrey A, Kay MA, Contag CH. Advancing Molecular Therapies through In Vivo Bioluminescent Imaging. Mol Imaging 2003; 2:75-86. [PMID: 12964305 DOI: 10.1162/15353500200303124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Effective development of therapeutics that target the molecular basis of disease is dependent on testing new therapeutic moieties and delivery strategies in animal models of human disease. Accelerating the analyses of these models and improving their predictive value through whole animal imaging methods, which provide data in real time and are sensitive to the subtle changes, are crucial for rapid advancement of these approaches. Modalities based on optics are rapid, sensitive, and accessible methods for in vivo analyses with relatively low instrumentation costs. In vivo bioluminescent imaging (BLI) is one of these optically based imaging methods that enable rapid in vivo analyses of a variety of cellular and molecular events with extreme sensitivity. BLI is based on the use of light-emitting enzymes as internal biological light sources that can be detected externally as biological indicators. BLI has been used to test spatio-temporal expression patterns of both target and therapeutic genes in living laboratory animals where the contextual influences of whole biological systems are preserved. BLI has also been used to analyze gene delivery, immune cell therapies, and the in vivo efficacy of inhibitory RNAs. New tools for BLI are being developed that will offer greater flexibility in detection and analyses. BLI can be used to accelerate the evaluation of experimental therapeutic strategies and whole body imaging offers the opportunity of revealing the effects of novel approaches on key steps in disease processes.
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Reporter genes for monitoring gene expression in mammalian cells. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0167-7306(03)38018-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Abstract
A heterogeneous, dual analyte-binding assay which makes use of the flash luminescence from both aequorin and an acridinium-9-carboxamide label is presented. The signal generating species were triggered both differentially and sequentially using Ca(2+) followed by basic peroxide. Both signals were resolved readily using a single photomultiplier tube without the need for multiwavelength detection. To demonstrate the tandem luminescence concept in a model assay system, dose-response curves for two analytes, biotinylated BSA and myoglobin, were generated using a competitive binding format. Because of the relatively short assay time and the well-resolved signals, this format will be useful in the development of dual analyte high-throughput assays.
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Affiliation(s)
- Maciej Adamczyk
- Department of Chemistry (9NM), Abbott Diagnostics Division, Abbott Laboratories, 60064-6016, Abbott Park, IL 60064-6016, USA.
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