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Li Y, Liu M, Kong Y, Guo L, Yu X, Yu W, Shen J, Wen K, Wang Z. Significantly improved detection performances of immunoassay for ractopamine in urine based on highly urea-tolerant rabbit monoclonal antibody. Food Chem Toxicol 2022; 168:113358. [PMID: 35964837 DOI: 10.1016/j.fct.2022.113358] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/21/2022] [Accepted: 08/06/2022] [Indexed: 10/16/2022]
Abstract
Highly sensitive and accurate screening of ractopamine (RAC) residue in animal urine is greatly needed to ensure food security. The detection performance of immunoassay for RAC was always seriously harmed by the antibody inactivation derived from urea. Here, we first discovered one rabbit monoclonal antibody (RmAb) to RAC with a high affinity of 0.007 ng mL-1 and a surprising urea tolerance of 3 M urea, which is beneficial for developing robustly developed immunoassay in urine without sample pretreatment. The limits of detection of developed indirect competitive enzyme-linked immunosorbent assay based on RmAb1 for RAC were 0.0042-0.014 μg L-1 with the coefficient of variation below 11.7% in swine, sheep, and cow urine, significantly improved 10-100-fold in sensitivity. Moreover, the urea-tolerant mechanism of RmAb1 showed that more non-polar amino acids, more hydrogen bond donors on the surface, and preponderant Pi interaction of antibody-RAC all contributed to the stability of the RmAb1 in a high concentration of urea.
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Affiliation(s)
- Yuan Li
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, Beijing Laboratory for Food Quality and Safety, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, People's Republic of China
| | - Minggang Liu
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, Beijing Laboratory for Food Quality and Safety, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, People's Republic of China
| | - Yihui Kong
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, Beijing Laboratory for Food Quality and Safety, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, People's Republic of China
| | - Lina Guo
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, Beijing Laboratory for Food Quality and Safety, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, People's Republic of China
| | - Xuezhi Yu
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, Beijing Laboratory for Food Quality and Safety, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, People's Republic of China
| | - Wenbo Yu
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, Beijing Laboratory for Food Quality and Safety, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, People's Republic of China
| | - Jianzhong Shen
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, Beijing Laboratory for Food Quality and Safety, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, People's Republic of China
| | - Kai Wen
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, Beijing Laboratory for Food Quality and Safety, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, People's Republic of China
| | - Zhanhui Wang
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, Beijing Laboratory for Food Quality and Safety, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, People's Republic of China.
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2
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de Rutte J, Dimatteo R, Archang MM, van Zee M, Koo D, Lee S, Sharrow AC, Krohl PJ, Mellody M, Zhu S, Eichenbaum JV, Kizerwetter M, Udani S, Ha K, Willson RC, Bertozzi AL, Spangler J, Damoiseaux R, Di Carlo D. Suspendable Hydrogel Nanovials for Massively Parallel Single-Cell Functional Analysis and Sorting. ACS NANO 2022; 16:7242-7257. [PMID: 35324146 PMCID: PMC9869715 DOI: 10.1021/acsnano.1c11420] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Techniques to analyze and sort single cells based on functional outputs, such as secreted products, have the potential to transform our understanding of cellular biology as well as accelerate the development of next-generation cell and antibody therapies. However, secreted molecules rapidly diffuse away from cells, and analysis of these products requires specialized equipment and expertise to compartmentalize individual cells and capture their secretions. Herein, we describe methods to fabricate hydrogel-based chemically functionalized microcontainers, which we call nanovials, and demonstrate their use for sorting single viable cells based on their secreted products at high-throughput using only commonly accessible laboratory infrastructure. These nanovials act as solid supports that facilitate attachment of a variety of adherent and suspension cell types, partition uniform aqueous compartments, and capture secreted proteins. Solutions can be exchanged around nanovials to perform fluorescence immunoassays on secreted proteins. Using this platform and commercial flow sorters, we demonstrate high-throughput screening of stably and transiently transfected producer cells based on relative IgG production. Chinese hamster ovary cells sorted based on IgG production regrew and maintained a high secretion phenotype over at least a week, yielding >40% increase in bulk IgG production rates. We also sorted hybridomas and B lymphocytes based on antigen-specific antibody production. Hybridoma cells secreting an antihen egg lysozyme antibody were recovered from background cells, enriching a population of ∼4% prevalence to >90% following sorting. Leveraging the high-speed sorting capabilities of standard sorters, we sorted >1 million events in <1 h. IgG secreting mouse B cells were also sorted and enriched based on antigen-specific binding. Successful sorting of antibody-secreting B cells combined with the ability to perform single-cell RT-PCR to recover sequence information suggests the potential to perform antibody discovery workflows. The reported nanovials can be easily stored and distributed among researchers, democratizing access to high-throughput functional cell screening.
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Affiliation(s)
- Joseph de Rutte
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
- Partillion Bioscience Corporation, Los Angeles, CA 90095, USA
| | - Robert Dimatteo
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA
| | - Maani M. Archang
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
| | - Mark van Zee
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
| | - Doyeon Koo
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
| | - Sohyung Lee
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA
| | - Allison C. Sharrow
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA
| | - Patrick J. Krohl
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21231, USA
| | - Michael Mellody
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA
| | - Sheldon Zhu
- Partillion Bioscience Corporation, Los Angeles, CA 90095, USA
| | - James V. Eichenbaum
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
| | - Monika Kizerwetter
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21231, USA
| | - Shreya Udani
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
| | - Kyung Ha
- Department of Mathematics, University of California, Los Angeles, CA 90095, USA
| | - Richard C. Willson
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204, USA
| | - Andrea L. Bertozzi
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA 90095, USA
- Department of Mathematics, University of California, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA
| | - Jamie Spangler
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21231, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21231, USA
- Translational Tissue Engineering Center, Johns Hopkins University, Baltimore, MD 21231, USA
| | - Robert Damoiseaux
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA
- Jonsson Comprehensive Cancer Center, University of California, Los Angeles, CA 90095, USA
| | - Dino Di Carlo
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA
- Jonsson Comprehensive Cancer Center, University of California, Los Angeles, CA 90095, USA
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3
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Abstract
Monoclonal antibodies are among the most significant biological tools used in medicine and biology that have revolutionized the field of diagnostics, therapeutics, and targeted drug delivery systems for many diseases. Among them, rabbit monoclonal antibodies have attracted significant attention for having high affinity and specificity. During the past few decades, different techniques have been developed to produce monoclonal antibodies. Single B cell cloning technology offers many advantages compared to other methods and has been used to generate monoclonal antibodies from different species including rabbits. This review briefly describes some of these methods, with main focus on single B cell cloning and production of rabbit monoclonal antibodies.
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4
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Kaneyoshi K, Yamano-Adachi N, Koga Y, Uchiyama K, Omasa T. Analysis of the immunoglobulin G (IgG) secretion efficiency in recombinant Chinese hamster ovary (CHO) cells by using Citrine-fusion IgG. Cytotechnology 2019; 71:193-207. [PMID: 30610509 PMCID: PMC6368511 DOI: 10.1007/s10616-018-0276-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 11/02/2018] [Indexed: 12/14/2022] Open
Abstract
Biopharmaceuticals represented by immunoglobulin G (IgG) are produced by the cultivation of recombinant animal cells, especially Chinese hamster ovary (CHO) cells. It is thought that the intracellular secretion process of IgG is a bottleneck in the production of biopharmaceuticals. Many studies on the regulation of endogenous secretory protein expression levels have shown improved productivity. However, these strategies have not universally improved the productivity of various proteins. A more rational and efficient establishment of high producer cells is required based on an understanding of the secretory processes in IgG producing CHO cells. In this study, a CHO cell line producing humanized IgG1, which was genetically fused with fluorescent proteins, was established to directly analyze intracellular secretion. The relationship between the amount of intracellular and secreted IgG was analyzed at the single cell level by an automated single-cell analysis and isolation system equipped with dual color fluorescent filters. The amounts of intracellular and secreted IgG showed a weak positive correlation. The amount of secreted IgG analyzed by the system showed a weak negative linear correlation with the specific growth of isolated clones. An immunofluorescent microscopy study showed that the established clones could be used to analyze the intracellular secretion bottleneck. This is the first study to report the use of fluorescent protein fusion IgG as a tool to analyze the secretion of recombinant CHO cells.
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Affiliation(s)
- Kohei Kaneyoshi
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 5650871, Japan
| | - Noriko Yamano-Adachi
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 5650871, Japan
- Manufacturing Technology Association of Biologics, 7-1-49 Minatojima-Minamimachi, Kobe, Hyogo, 6500047, Japan
| | - Yuichi Koga
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 5650871, Japan
| | - Keiji Uchiyama
- The Institute for Enzyme Research, Tokushima University, 3-18-15 Kuramoto, Tokushima, Tokushima, 7708503, Japan
| | - Takeshi Omasa
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 5650871, Japan.
- Manufacturing Technology Association of Biologics, 7-1-49 Minatojima-Minamimachi, Kobe, Hyogo, 6500047, Japan.
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5
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Priola JJ, Calzadilla N, Baumann M, Borth N, Tate CG, Betenbaugh MJ. High-throughput screening and selection of mammalian cells for enhanced protein production. Biotechnol J 2016; 11:853-65. [DOI: 10.1002/biot.201500579] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 02/09/2016] [Accepted: 05/17/2016] [Indexed: 01/05/2023]
Affiliation(s)
- Joseph J. Priola
- Department of Chemical and Biomolecular Engineering; Johns Hopkins University; Baltimore MD USA
| | - Nathan Calzadilla
- Department of Chemical and Biomolecular Engineering; Johns Hopkins University; Baltimore MD USA
| | | | - Nicole Borth
- Department of Biotechnology; Universität für Bodenkultur; Vienna Austria
| | | | - Michael J. Betenbaugh
- Department of Chemical and Biomolecular Engineering; Johns Hopkins University; Baltimore MD USA
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6
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Generation of Recombinant Monoclonal Antibodies from Immunised Mice and Rabbits via Flow Cytometry and Sorting of Antigen-Specific IgG+ Memory B Cells. PLoS One 2016; 11:e0152282. [PMID: 27022949 PMCID: PMC4811437 DOI: 10.1371/journal.pone.0152282] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 03/12/2016] [Indexed: 11/29/2022] Open
Abstract
Single B cell screening strategies, which avoid both hybridoma fusion and combinatorial display, have emerged as important technologies for efficiently sampling the natural antibody repertoire of immunized animals and humans. Having access to a range of methods to interrogate different B cell subsets provides an attractive option to ensure large and diverse panels of high quality antibody are produced. The generation of multiple antibodies and having the ability to find rare B cell clones producing IgG with unique and desirable characteristics facilitates the identification of fit-for-purpose molecules that can be developed into therapeutic agents or research reagents. Here, we describe a multi-parameter flow cytometry single-cell sorting technique for the generation of antigen-specific recombinant monoclonal antibodies from single IgG+ memory B cells. Both mouse splenocytes and rabbit PBMC from immunised animals were used as a source of B cells. Reagents staining both B cells and other unwanted cell types enabled efficient identification of class-switched IgG+ memory B cells. Concurrent staining with antigen labelled separately with two spectrally-distinct fluorophores enabled antigen-specific B cells to be identified, i.e. those which bind to both antigen conjugates (double-positive). These cells were then typically sorted at one cell per well using FACS directly into a 96-well plate containing reverse transcriptase reaction mix. Following production of cDNA, PCR was performed to amplify cognate heavy and light chain variable region genes and generate transcriptionally-active PCR (TAP) fragments. These linear expression cassettes were then used directly in a mammalian cell transfection to generate recombinant antibody for further testing. We were able to successfully generate antigen-specific recombinant antibodies from both the rabbit and mouse IgG+ memory B cell subset within one week. This included the generation of an anti-TNFR2 blocking antibody from mice with an affinity of 90 pM.
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Torres A, Hill AS, Love JC. Nanowell-based immunoassays for measuring single-cell secretion: characterization of transport and surface binding. Anal Chem 2014; 86:11562-9. [PMID: 25347613 PMCID: PMC4255675 DOI: 10.1021/ac4030297] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Accepted: 10/27/2014] [Indexed: 12/17/2022]
Abstract
Arrays of subnanoliter wells (nanowells) provide a useful system to isolate single cells and analyze their secreted proteins. Two general approaches have emerged: one that uses open arrays and local capture of secreted proteins, and a second (called microengraving) that relies on closed arrays to capture secreted proteins on a solid substrate, which is subsequently removed from the array. However, the design and operating parameters for efficient capture from these two approaches to analyze single-cell secretion have not been extensively considered. Using numerical simulations, we analyzed the operational envelope for both open and closed formats, as a function of the spatial distribution of capture ligands, their affinities for the protein, and the rates of single-cell secretion. Based on these analyses, we present a modified approach to capture secreted proteins in-well for highly active secreting cells. This simple method for in-well detection should facilitate rapid identification of cell lines with high specific productivities.
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Affiliation(s)
- Alexis
J. Torres
- Department of Chemical Engineering, Department of Biological
Engineering, and Koch Institute for
Integrative Cancer Research, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Abby S. Hill
- Department of Chemical Engineering, Department of Biological
Engineering, and Koch Institute for
Integrative Cancer Research, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - J. Christopher Love
- Department of Chemical Engineering, Department of Biological
Engineering, and Koch Institute for
Integrative Cancer Research, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139, United States
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8
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Clargo AM, Hudson AR, Ndlovu W, Wootton RJ, Cremin LA, O'Dowd VL, Nowosad CR, Starkie DO, Shaw SP, Compson JE, White DP, MacKenzie B, Snowden JR, Newnham LE, Wright M, Stephens PE, Griffiths MR, Lawson ADG, Lightwood DJ. The rapid generation of recombinant functional monoclonal antibodies from individual, antigen-specific bone marrow-derived plasma cells isolated using a novel fluorescence-based method. MAbs 2014; 6:143-59. [PMID: 24423622 DOI: 10.4161/mabs.27044] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Single B cell technologies, which avoid traditional hybridoma fusion and combinatorial display, provide a means to interrogate the naturally-selected antibody repertoire of immunized animals. Many methods enable the sampling of memory B cell subsets, but few allow for the direct interrogation of the plasma cell repertoire, i.e., the subset of B cells responsible for producing immunoglobulin in serum. Here, we describe the use of a robust and simple fluorescence-based technique, called the fluorescent foci method, for the identification and isolation of antigen-specific IgG-secreting cells, such as plasma cells, from heterogeneous bone marrow preparations. Following micromanipulation of single cells, cognate pairs of heavy and light chain variable region genes were recovered by reverse transcription (RT)-polymerase chain reaction (PCR). During the PCR, variable regions were combined with a promoter fragment and a relevant constant region fragment to produce two separate transcriptionally-active PCR (TAP) fragments that were directly co-transfected into a HEK-293F cell line for recombinant antibody expression. The technique was successfully applied to the generation of a diverse panel of high-affinity, functional recombinant antibodies to human tumor necrosis factor (TNF) receptor 2 and TNF derived from the bone marrow of immunized rabbits and rats, respectively. Progression from a bone marrow sample to a panel of functional recombinant antibodies was possible within a 2-week timeframe.
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9
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Junkin M, Tay S. Microfluidic single-cell analysis for systems immunology. LAB ON A CHIP 2014; 14:1246-60. [PMID: 24503696 DOI: 10.1039/c3lc51182k] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The immune system constantly battles infection and tissue damage, but exaggerated immune responses lead to allergies, autoimmunity and cancer. Discrimination of self from foreign and the fine-tuning of immunity are achieved by information processing pathways, whose regulatory mechanisms are little understood. Cell-to-cell variability and stochastic molecular interactions result in diverse cellular responses to identical signaling inputs, casting doubt on the reliability of traditional population-averaged analyses. Furthermore, dynamic molecular and cellular interactions create emergent properties that change over multiple time scales. Understanding immunity in the face of complexity and noisy dynamics requires time-dependent analysis of single-cells in a proper context. Microfluidic systems create precisely defined microenvironments by controlling fluidic and surface chemistries, feature sizes, geometries and signal input timing, and thus enable quantitative multi-parameter analysis of single cells. Such qualities allow observable dynamic environments approaching in vivo levels of biological complexity. Seamless parallelization of functional units in microfluidic devices allows high-throughput measurements, an essential feature for statistically meaningful analysis of naturally variable biological systems. These abilities recapitulate diverse scenarios such as cell-cell signaling, migration, differentiation, antibody and cytokine production, clonal selection, and cell lysis, thereby enabling accurate and meaningful study of immune behaviors in vitro.
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Affiliation(s)
- Michael Junkin
- Department of Biosystems Science and Engineering, ETH Zürich, Switzerland.
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Gierahn TM, Loginov D, Love JC. Crossword: a fully automated algorithm for the segmentation and quality control of protein microarray images. J Proteome Res 2014; 13:362-71. [PMID: 24417579 PMCID: PMC3979532 DOI: 10.1021/pr401167h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Biological assays formatted as microarrays have become a critical tool for the generation of the comprehensive data sets required for systems-level understanding of biological processes. Manual annotation of data extracted from images of microarrays, however, remains a significant bottleneck, particularly for protein microarrays due to the sensitivity of this technology to weak artifact signal. In order to automate the extraction and curation of data from protein microarrays, we describe an algorithm called Crossword that logically combines information from multiple approaches to fully automate microarray segmentation. Automated artifact removal is also accomplished by segregating structured pixels from the background noise using iterative clustering and pixel connectivity. Correlation of the location of structured pixels across image channels is used to identify and remove artifact pixels from the image prior to data extraction. This component improves the accuracy of data sets while reducing the requirement for time-consuming visual inspection of the data. Crossword enables a fully automated protocol that is robust to significant spatial and intensity aberrations. Overall, the average amount of user intervention is reduced by an order of magnitude and the data quality is increased through artifact removal and reduced user variability. The increase in throughput should aid the further implementation of microarray technologies in clinical studies.
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Affiliation(s)
- Todd M Gierahn
- Department of Chemical Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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Rapid identification and drug susceptibility screening of ESAT-6 secreting Mycobacteria by a NanoELIwell assay. Sci Rep 2012; 2:635. [PMID: 22957139 PMCID: PMC3434393 DOI: 10.1038/srep00635] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/10/2012] [Indexed: 01/05/2023] Open
Abstract
To meet the global needs of tuberculosis (TB) control, a nanoELIwell device was developed as a multifunctional assay for TB diagnosis and drug susceptibility testing. The device integrates on-chip culturing of mycobacteria, immunoassay, and high-resolution fluorescent imaging. Mycobacterium smegmatis and Mycobacterium kansasii were used as models of Mycobacterium tuberculosis to evaluate device integrity by using antigens, Ag85 and ESAT-6, as biomarkers. As a result, the nanoELIwell device detected antigens released from a single bacterium within 24–48-hour culture. Antimycobacterial drug-treated M. smegmatis showed significant decreased in Ag85 antigen production when treated with ethambutol and no change in antigen production when treated with rifampin, demonstrating drug susceptibility and resistance, respectively. The nanoELIwell assay also distinguished the ESAT-6-secreting M. kansasii from the non-ESAT-6-secreting M. simiae. The combination of microwell technology and ELISA assay holds potential to the development of a rapid, sensitive, and specific diagnostics and susceptibility testing of TB.
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