Name: standardization of transfer across labs between flow cytometers for detection of lymphocytes in japanese encephalitis vaccinated children
Uploaded: 2023-02-10T13:30:00
Description: Watch this Scientific Journal Video about Standardization of Transfer across Labs between Flow Cytometers for Detection of Lymphocytes in Japanese Encephalitis Vaccinated Children at JoVE.com

RW was supported by Beijing Natural Science Foundation, China (No. 7222059), National Natural Science Foundation of China (No. 82002130), XZ was supported by the CAMS Innovation Fund for Medical Sciences (No. 2019-I2M-5-026).

The study was approved by the Ethics Committee of Beijing Children&#39;s Hospital, Capital Medical University (Approval Number: 2020-k-85). Informed consent of human subjects was waived as only residual samples after clinical testing were used in this study. Two labs are involved in this study. The transferring lab is where the standardized method was developed using one flow cytometer. The cytometer in this lab is hereinafter referred to as cytometer A. The test method lab</stro...

<ol>
	<li>Cabanski, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow+cytometric+method+transfer:+Recommendations+for+best+practice.">Flow cytometric method transfer: Recommendations for best practice.</a> Cytometry Part B. Clinical Cytometry. 100 (1), 52-62 (2021).</li><li>Le Lann, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standardization+procedure+for+flow+cytometry+data+harmonization+in+prospective+multicenter+studies.">Standardization procedure for flow cytometry data harmonization in prospective multicenter studies.</a> Scientific Reports. 10 (1), 11567 (2020).</li><li>Linskens, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+standardization+of+flow+cytometry+diagnostic+screening+of+primary+immunodeficiency+by+software-based+automated+gating.">Improved standardization of flow cytometry diagnostic screening of primary immunodeficiency by software-based automated gating.</a> Frontiers in Immunology. 11, 584646 (2020).</li><li>Glier, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standardization+of+8-color+flow+cytometry+across+different+flow+cytometer+instruments:+A+feasibility+study+in+clinical+laboratories+in+Switzerland.">Standardization of 8-color flow cytometry across different flow cytometer instruments: A feasibility study in clinical laboratories in Switzerland.</a> Journal of Immunological Methods. 475, 112348 (2019).</li><li>Wang, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+epidemiology+and+disease+burden+of+children+hospitalized+for+viral+infections+within+the+family+Flaviviridae+in+China:+A+national+cross-sectional+study.">The epidemiology and disease burden of children hospitalized for viral infections within the family Flaviviridae in China: A national cross-sectional study.</a> PLOS Neglected Tropical Diseases. 16 (7), e0010562 (2022).</li><li>Ding, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reference+values+for+peripheral+blood+lymphocyte+subsets+of+healthy+children+in+China.">Reference values for peripheral blood lymphocyte subsets of healthy children in China.</a> The Journal of Allergy and Clinical Immunology. 142 (3), 970-973 (2018).</li><li>Zhang, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+polyfunctional+T+cells+in+children+vaccinated+with+Japanese+encephalitis+vaccine+via+the+flow+cytometry+technique.">Detection of polyfunctional T cells in children vaccinated with Japanese encephalitis vaccine via the flow cytometry technique.</a> Journal of Visualized Experiments. (187), e64671 (2022).</li><li>Yu, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CD4(+)+CD25+(+)+CD127+(low/-)+T+cells:+a+more+specific+Treg+population+in+human+peripheral+blood.">CD4(+) CD25 (+) CD127 (low/-) T cells: a more specific Treg population in human peripheral blood.</a> Inflammation. 35 (6), 1773-1180 (2012).</li><li>Kalina, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reproducibility+of+flow+cytometry+through+standardization:+opportunities+and+challenges.">Reproducibility of flow cytometry through standardization: opportunities and challenges.</a> Cytometry Part A. 97 (2), 137-147 (2020).</li><li>Sommer, U., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Implementation+of+highly+sophisticated+flow+cytometry+assays+in+multicenter+clinical+studies:+considerations+and+guidance.">Implementation of highly sophisticated flow cytometry assays in multicenter clinical studies: considerations and guidance.</a> Bioanalysis. 7 (10), 1299-1311 (2015).</li><li>Glier, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comments+on+EuroFlow+standard+operating+procedures+for+instrument+setup+and+compensation+for+BD+FACS+Canto+II,+Navios+and+BD+FACS+Lyric+instruments.">Comments on EuroFlow standard operating procedures for instrument setup and compensation for BD FACS Canto II, Navios and BD FACS Lyric instruments.</a> Journal of Immunological Methods. 475, 112680 (2019).</li></ol>

Immunophenotyping of peripheral blood lymphocyte subsets can help understand the changes in cell-mediated adaptive immunity after vaccination in children. In clinical applications, unexpected situations occur, such as a failure to detect samples in a timely manner or the replacement of a flow cytometer; therefore, rapid standardized methods that facilitate transfers between flow cytometers in different labs are needed9,10,11. He...

The standardization of flow cytometry is useful for the comparability of results obtained from different cytometers across different laboratories and study centers, and conducive to the mutual recognition of results to improve work efficiency. An increasing number of scenarios require standardization. During the drug development process, flow cytometry standardization is important, as a developed and validated assay will support the whole drug development process from preclinical to clinical analysis. Flow cytometric methods are frequently transferred between the pharmaceutical industry and collaborating laboratories1. Moreover, it is essential to obtain comparable data from multicentric clinical studies. For example, a standardization workflow was developed in the Systemic Autoimmune Diseases Multicenter Clinical Research Project to obtain comparable data from multicentric flow cytometry2.
The standardization of flow cytometry methods is challenging. The challenges experienced across labs are attributed to the lack of standardized materials, software compatibility issues, inconsistencies in instrument setup, and the use of different configurations among different flow cytometers and divergent gating strategies between the centers3,4. Therefore, it is important to conduct a gap analysis between laboratories. Sample access, quality systems, personnel qualifications, and instrument configuration must be reviewed to ensure that the requirements are met.
At present, children vaccinated with the Japanese encephalitis (JE) vaccine have a significantly reduced incidence of JE5. Monitoring peripheral blood immune cells can help understand the changes in cell-mediated adaptive immunity after vaccination, and the correlation between the changes in peripheral blood lymphocyte subsets and the effects of vaccination. Due to the limited stability of whole blood samples, evaluations of vaccine efficacy are often performed in multiple centers. For this analysis, we defined na&#239;ve CD8+ or CD4+ T cells as CD27+ CD45RA+, central memory T cells (TCM) as CD27+ CD45RA-, effector memory T cells (TEM) as CD27- CD45RA-,&#160;and terminally differentiated effector memory T cells (TEMRA) as CD27- CD45RA+. CD19+ B cells can be separated into populations that express CD27 versus IgD6,7, na&#239;ve B cells express CD27n memory B cells (mBCs) can be identified based on the expression of IgD6, and regulatory T cells (Tregs) can be identified as CD4+CD25++CD127low 8. To establish a standardized flow cytometry experiment to achieve the consistency and comparability of experimental results in multiple centers, a rapid and feasible standardization method was established to facilitate the transfer of protocols across different flow cytometers for the detection of lymphocytes in the whole blood of JE-vaccinated children. Six healthy children (2 years old) were recruited from Beijing Children&#39;s Hospital, Capital Medical University. After receiving a prime and boost vaccination with a live-attenuated JE SA14-14-2 vaccine less than 6 months prior, peripheral blood samples were collected from the volunteers. Highly comparable data were obtained from different instruments following standardized procedures, which is helpful for multicenter assessments.

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			<td>BD CompBeads Anti-Mouse Ig, &#954;/Negative Control Compensation Particles Set</td>
			<td>BD</td>
			<td>552843</td>
			<td>compensation</td>
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		<tr>
			<td>BD FACSCanto</td>
			<td>BD</td>
			<td>FACSCanto</td>
			<td>flow Cytometry A in the transferring lab</td>
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		<tr>
			<td>BD FACSDiva CS&#38;T Research Beads</td>
			<td>BD</td>
			<td>655051</td>
			<td>define flow cytometer baseline and track cytometer performance</td>
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		<tr>
			<td>BD Horizon BV421 Mouse Anti-Human CD127</td>
			<td>BD</td>
			<td>562436</td>
			<td>Fluorescent antibody&#160;</td>
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			<td>BD Horizon BV605 Mouse Anti-Human CD27</td>
			<td>BD</td>
			<td>562656</td>
			<td>Fluorescent antibody&#160;</td>
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		<tr>
			<td>BD Horizon V500 Mouse Anti-Human CD45</td>
			<td>BD</td>
			<td>560777</td>
			<td>Fluorescent antibody&#160;</td>
		</tr>
		<tr>
			<td>BD LSRFortessa</td>
			<td>BD</td>
			<td>LSRFortessa</td>
			<td>flow Cytometry B in the test method lab</td>
		</tr>
		<tr>
			<td>BD OptiBuild BB700 Mouse Anti-Human CD19</td>
			<td>BD</td>
			<td>745907</td>
			<td>Fluorescent antibody&#160;</td>
		</tr>
		<tr>
			<td>BD OptiBuild R718 Mouse Anti-Human CD8</td>
			<td>BD</td>
			<td>751953</td>
			<td>Fluorescent antibody&#160;</td>
		</tr>
		<tr>
			<td>BD Pharmingen APC Mouse Anti-Human CD45RA</td>
			<td>BD</td>
			<td>550855</td>
			<td>Fluorescent antibody&#160;</td>
		</tr>
		<tr>
			<td>BD Pharmingen APC-H7 Mouse Anti-Human CD3</td>
			<td>BD</td>
			<td>560176</td>
			<td>Fluorescent antibody&#160;</td>
		</tr>
		<tr>
			<td>BD Pharmingen FITC Mouse Anti-Human CD4</td>
			<td>BD</td>
			<td>566320</td>
			<td>Fluorescent antibody&#160;</td>
		</tr>
		<tr>
			<td>BD Pharmingen PE Mouse Anti-Human CD25</td>
			<td>BD</td>
			<td>555432</td>
			<td>Fluorescent antibody&#160;</td>
		</tr>
		<tr>
			<td>BD Pharmingen PE-Cy7 Mouse Anti-Human IgD</td>
			<td>BD</td>
			<td>561314</td>
			<td>Fluorescent antibody&#160;</td>
		</tr>
		<tr>
			<td>Brilliant Staining Buffer Plus</td>
			<td>BD</td>
			<td>566385</td>
			<td>Staining Buffer</td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Eppendorf</td>
			<td>5810</td>
			<td>Cell centrifugation</td>
		</tr>
		<tr>
			<td>Centrifuge Tube</td>
			<td>BD Falcon</td>
			<td>BD-35209715</td>
			<td>15 mL centrifuge tube</td>
		</tr>
		<tr>
			<td>CS&#38;T IVD Beads</td>
			<td>BD</td>
			<td>662414</td>
			<td>standard beads to setup cytometer settings in different flow cytometer</td>
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			<td>Lysing Solution 10x Concentrate</td>
			<td>BD</td>
			<td>349202</td>
			<td>lysing red blood cells</td>
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			<td>Phosphate-buffered Saline (PBS)</td>
			<td>Gibco</td>
			<td>10010-023</td>
			<td>PBS</td>
		</tr>
		<tr>
			<td>Round-bottom test tube</td>
			<td>BD Falcon</td>
			<td>352235</td>
			<td>5 mL test tube</td>
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standardization of transfer across labs between flow cytometers for detection of lymphocytes in japanese encephalitis vaccinated children

An increasing number of laboratories need to collect data from multiple flow cytometers, especially for research projects performed across multiple centers. The challenges of using two flow cytometers in different labs include the lack of standardized materials, software compatibility issues, inconsistencies in instrument setup, and the use of different configurations for different flow cytometers. To establish a standardized flow cytometry experiment to achieve the consistency and comparability of experimental results across multiple centers, a rapid and feasible standardization method was established to transfer parameters across different flow cytometers. 
The methods developed in this study allowed the transfer of experimental settings and analysis templates between two flow cytometers in different laboratories for the detection of lymphocytes in Japanese encephalitis (JE)-vaccinated children. A consistent fluorescence intensity was obtained between the two cytometers using fluorescence standard beads to establish the cytometer settings. Comparable results were obtained in two laboratories with different types of instruments. Using this method, we can standardize analysis for evaluating the immune function of JE-vaccinated children in different laboratories with different instruments, diminish the differences in data and results among flow cytometers in multiple centers, and provide a feasible approach for the mutual accreditation of laboratory results. The standardization method of flow cytometer experiments will ensure the effective performance of research projects across multiple centers.

Figure 1&#160;shows a global worksheet of the target value template for the CST bright beads. Using an FSC/SSC plot, a polygon gate is drawn to select the CST bright beads. Histogram plots of 10 fluorescence channels were obtained for the CST bright beads: FITC, PE, BB700, PE-Cy7, APC, R718, APC-H7, BV421, V500, and BV605. The target value for each parameter is displayed by showing the median within the histogram gates in Table 2. The screenshots of templates and parameter s...

Watch this Scientific Journal Video about Standardization of Transfer across Labs between Flow Cytometers for Detection of Lymphocytes in Japanese Encephalitis Vaccinated Children at JoVE.com

Standardization of Transfer across Labs between Flow Cytometers for Detection of Lymphocytes in Japanese Encephalitis Vaccinated Children

In this study, a method was developed to facilitate the transfer of experimental settings and analysis templates between two flow cytometers in two laboratories for the detection of lymphocytes in Japanese encephalitis-vaccinated children. The standardization method for the flow cytometer experiments will allow research projects to be effectively conducted in multiple centers.

An increasing number of laboratories need to collect data from multiple flow cytometers, especially for research projects performed across multiple ...

The standardization method of the flow cytometer provide a feasible approach for the mutual accreditation of laboratory results and ensures the consistency of results with research projects across multiple centers. The method minimize time consumption is easy to execute, is equipped to automate, analyzes template, and can dramatically reduce the requirement of data analysis. Begin creating a new configuration in the software of cytometer A, from the transferring lab, by clicking the cytometer button, and choosing view configurations.Right click the base configurations folder in the configuration list, choose new folder and rename it. Next, create a new configuration by right clicking the base configuration and copying it. Right click the new folder and paste the base configuration before renaming the new configuration, Standardized method transfer"Drag the parameter name, such as, FETC from the parameters list, onto the appropriate detector 530/30, also edit additional parameters to the new configuration.To standardize the experiment in the transferring lab, run a performance check using this cytometer A setup and track the beads to verify that the cytometer A is performing well. Right click cytometer A settings in the software browser window and create a worksheet by selecting the application settings. Then use an unstained sample to adjust the photo multiplier tube, or PMT voltages, of the forward scattering area, or FSC, and side scattering area, or SSC, and all fluorescence parameters.Save the application settings by right-clicking the experiment cytometer settings and selecting application settings. To add compensation controls automatically, click on the experiment button and select the compensation setup menu, before selecting create compensation controls. Record data for all compensation control beads.Once done, click on the experiment and select compensation setup, calculate the compensation automatically, before recording the data for single cell stained controls. use CD45 RAA APC to modify the compensation value of R7-18 to 15%APC, use CD19 BB700 to modify the compensation value of APC H7 to 14%BB700, and use CD8 R7-18 to modify the compensation value of APC H7 to 60%R7-18. After recording the data for the CST beads, create a global worksheet of the target value template for the CST bright beads, once done, run the samples on the flow cytometer array and collect 25, 000 lymphocytes.Create a global worksheet of the analysis template for the samples and save the experimental template on cytometer A.Export the experimental template using the CD-ROM. To transfer the experimental template to cytometer B in the test lab, conduct a performance check using CST beads to verify that cytometer B is performing well. Import the experimental template from cytometer A and create an experiment for cytometer B using the template.Using the same lot of CST beads adjust the fluorescent parameter voltages for each fluorescence channel to match the previous MFI instrument. If needed, adjust the FSC voltage using the unstained sample. Right click on the experimental cytometer settings and select application settings to save the application settings.Next, modify the compensation value of R7-18 to 15%APC using CD45 RA APC. Use CD19 BB700 to modify the compensation value of APC H7 to 24%BB700. And use CD8 R7-18 to modify the compensation value of APC H7 to 60%R7-18.After compensation value modification, run the samples on the flow cytometer B and collect 25, 000 lymphocytes. In a global worksheet of the target value template for the cytometer setup and tracking, or CST bright beads, the histogram plots of 10 fluorescence channels were obtained, the target value for each parameter was displayed by showing the median within the histogram gates. the dot plots of the sample obtained using the cytometer A and B after instrument standardization, demonstrated the consistency of data between different instruments using an automatic analysis template.No significant difference was observed when the results from six samples were compared across two different instrument models. The results of 15 lymphoid subsets obtained from different instruments using the standardized method acquired highly comparable data. The same configuration name, creating the template, and making the ecotech values of safety beads in different instruments are critical steps in this protocol.

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Research

JoVE Journal

Immunology and Infection

Combination of Adhesive-tape-based Sampling and Fluorescence in situ Hybridization for Rapid Detection of Salmonella on Fresh Produce

This protocol describes a simple approach for adhesive-tape-based sampling of tomato and other fresh produce surfaces, followed by on-tape fluorescence in situ hybridization (FISH) for rapid culture-independent detection of Salmonella spp. Cell-charged tapes can also be placed face-down on selective agar for solid-phase enrichment prior to detection. Alternatively, low-volume liquid enrichments (liquid surface miniculture) can be performed on the surface of the tape in non-selective broth, followed by FISH and analysis via flow cytometry. To begin, sterile adhesive tape is brought into contact with fresh produce, gentle pressure is applied, and the tape is removed, physically extracting microbes present on these surfaces. Tapes are mounted sticky-side up onto glass microscope slides and the sampled cells are fixed with 10% formalin (30 min) and dehydrated using a graded ethanol series (50, 80, and 95%; 3 min each concentration). Next, cell-charged tapes are spotted with buffer containing a Salmonella-targeted DNA probe cocktail and hybridized for 15 - 30 min at 55&deg;C, followed by a brief rinse in a washing buffer to remove unbound probe. Adherent, FISH-labeled cells are then counterstained with the DNA dye 4',6-diamidino-2-phenylindole (DAPI) and results are viewed using fluorescence microscopy. For solid-phase enrichment, cell-charged tapes are placed face-down on a suitable selective agar surface and incubated to allow in situ growth of Salmonella microcolonies, followed by FISH and microscopy as described above. For liquid surface miniculture, cell-charged tapes are placed sticky side up and a silicone perfusion chamber is applied so that the tape and microscope slide form the bottom of a water-tight chamber into which a small volume (&le; 500 &mu;L) of Trypticase Soy Broth (TSB) is introduced. The inlet ports are sealed and the chambers are incubated at 35 - 37&deg;C, allowing growth-based amplification of tape-extracted microbes. Following incubation, inlet ports are unsealed, cells are detached and mixed with vigorous back and forth pipetting, harvested via centrifugation and fixed in 10% neutral buffered formalin. Finally, samples are hybridized and examined via flow cytometry to reveal the presence of Salmonella spp. As described here, our "tape-FISH" approach can provide simple and rapid sampling and detection of Salmonella on tomato surfaces. We have also used this approach for sampling other types of fresh produce, including spinach and jalape&ntilde;o peppers.

Combination of Adhesive-tape-based Sampling and Fluorescence in situ Hybridization for Rapid Detection of Salmonella on Fresh Produce

This protocol describes a simple adhesive-tape-based approach for sampling of tomato and other fresh produce surfaces, followed by rapid whole cell detection of Salmonella using fluorescence in situ hybridization (FISH).

This protocol describes a simple approach for adhesive-tape-based sampling of tomato and other fresh produce surfaces, followed by on-tape fluorescence in ...

Locked Nucleic Acid Flow Cytometry-fluorescence in situ Hybridization (LNA flow-FISH): a Method for Bacterial Small RNA Detection

Fluorescence in situ hybridization (FISH) is a powerful technique that is used to detect and localize specific nucleic acid sequences in the cellular environment. In order to increase throughput, FISH can be combined with flow cytometry (flow-FISH) to enable the detection of targeted nucleic acid sequences in thousands of individual cells. As a result, flow-FISH offers a distinct advantage over lysate/ensemble-based nucleic acid detection methods because each cell is treated as an independent observation, thereby permitting stronger statistical and variance analyses. These attributes have prompted the use of FISH and flow-FISH methods in a number of different applications and the utility of these methods has been successfully demonstrated in telomere length determination1,2, cellular identification and gene expression3,4, monitoring viral multiplication in infected cells5, and bacterial community analysis and enumeration6.
Traditionally, the specificity of FISH and flow-FISH methods has been imparted by DNA oligonucleotide probes. Recently however, the replacement of DNA oligonucleotide probes with nucleic acid analogs as FISH and flow-FISH probes has increased both the sensitivity and specificity of each technique due to the higher melting temperatures (Tm) of these analogs for natural nucleic acids7,8. Locked nucleic acid (LNA) probes are a type of nucleic acid analog that contain LNA nucleotides spiked throughout a DNA or RNA sequence9,10. When coupled with flow-FISH, LNA probes have previously been shown to outperform conventional DNA probes7,11 and have been successfully used to detect eukaryotic mRNA12 and viral RNA in mammalian cells5.
Here we expand this capability and describe a LNA flow-FISH method which permits the specific detection of RNA in bacterial cells (Figure 1). Specifically, we are interested in the detection of small non-coding regulatory RNA (sRNA) which have garnered considerable interest in the past few years as they have been found to serve as key regulatory elements in many critical cellular processes13. However, there are limited tools to study sRNAs and the challenges of detecting sRNA in bacterial cells is due in part to the relatively small size (typically 50-300 nucleotides in length) and low abundance of sRNA molecules as well as the general difficulty in working with smaller biological cells with varying cellular membranes. In this method, we describe fixation and permeabilzation conditions that preserve the structure of bacterial cells and permit the penetration of LNA probes as well as signal amplification steps which enable the specific detection of low abundance sRNA (Figure 2).

Locked Nucleic Acid Flow Cytometry-fluorescence in situ Hybridization LNA flow-FISH: a Method for Bacterial Small RNA Detection

A novel high-throughput method is described that enables the detection and relative quantitation of small RNA and mRNA expression from single bacterial cells using locked nucleic acid probes and flow cytometry-fluorescence in situ hybridization.

Fluorescence in situ hybridization (FISH) is a powerful technique that is used to detect and localize specific nucleic acid sequences in the cellular ...

Total Protein Extraction and 2-D Gel Electrophoresis Methods for Burkholderia Species

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Total Protein Extraction and 2-D Gel Electrophoresis Methods for Burkholderia Species

Members of the Burkholderia genus are pathogens of clinical importance. We describe a method for total bacterial protein extraction, using mechanical disruption, and 2-D gel electrophoresis for subsequent proteomic analysis.

The investigation of  the intracellular protein levels of bacterial species is of importance to  understanding the pathogenic mechanisms of diseases ...

Detection of Fluorescent Nanoparticle Interactions with Primary Immune Cell Subpopulations by Flow Cytometry

Engineered nanoparticles are endowed with very promising properties for therapeutic and diagnostic purposes. This work describes a fast and reliable method of analysis by flow cytometry to study nanoparticle interaction with immune cells. Primary immune cells can be easily purified from human or mouse tissues by antibody-mediated magnetic isolation. In the first instance, the different cell populations running in a flow cytometer can be distinguished by the forward-scattered light (FSC), which is proportional to cell size, and the side-scattered light (SSC), related to cell internal complexity. Furthermore, fluorescently labeled antibodies against specific cell surface receptors permit the identification of several subpopulations within the same sample. Often, all these features vary when cells are boosted by external stimuli that change their physiological and morphological state. Here, 50 nm FITC-SiO2 nanoparticles are used as a model to identify the internalization of nanostructured materials in human blood immune cells. The cell fluorescence and side-scattered light increase after incubation with nanoparticles allowed us to define time and concentration dependence of nanoparticle-cell interaction. Moreover, such protocol can be extended to investigate Rhodamine-SiO2 nanoparticle interaction with primary microglia, the central nervous system resident immune cells, isolated from mutant mice that specifically express the Green Fluorescent Protein (GFP) in the monocyte/macrophage lineage. Finally, flow cytometry data related to nanoparticle internalization into the cells have been confirmed by confocal microscopy.

Analysis of nanoparticle interaction with defined subpopulations of immune cells by flow cytometry.

Engineered nanoparticles are endowed with very promising properties for therapeutic and diagnostic purposes. This work describes a fast and reliable ...

Static Adhesion Assay for the Study of Integrin Activation in T Lymphocytes

T lymphocyte adhesion is required for multiple T cell functions, including migration to sites of inflammation and formation of immunological synapses with antigen presenting cells. T cells accomplish regulated adhesion by controlling the adhesive properties of integrins, a class of cell adhesion molecules consisting of heterodimeric pairs of transmembrane proteins that interact with target molecules on partner cells or extracellular matrix. The most prominent T cell integrin is lymphocyte function associated antigen (LFA)-1, composed of subunits &#945;L and &#946;2, whose target is the intracellular adhesion molecule (ICAM)-1. The ability of a T cell to control adhesion derives from the ability to regulate the affinity states of individual integrins. Inside-out signaling describes the process whereby signals inside a cell cause the external domains of integrins to assume an activated state. Much of our knowledge of these complex phenomena is based on mechanistic studies performed in simplified in&#160;vitro model systems. The T lymphocyte adhesion assay described here is an excellent tool that allows T cells to adhere to target molecules, under static conditions, and then utilizes a fluorescent plate reader to quantify adhesiveness. This assay has been useful in defining adhesion-stimulatory or inhibitory substances that act on lymphocytes, as well as characterizing the signaling events involved. Although described here for LFA-1 - ICAM-1 mediated adhesion; this assay can be readily adapted to allow for the study of other adhesive interactions (e.g.&#160;VLA-4 - fibronectin).

Static adhesion assay is a powerful tool that can be used to model the interactions between T lymphocytes and other cell types. Interactions are generated by injecting labeled T cells into wells coated with adhesion molecules, while a plate reader is used to quantify the number of adherent cells following serial washes.

T lymphocyte adhesion is required for multiple T cell functions, including migration to sites of inflammation and formation of immunological synapses with ...

A Simple and Rapid Protocol to Non-enzymatically Dissociate Fresh Human Tissues for the Analysis of Infiltrating Lymphocytes

The ability of malignant cells to evade the immune system, characterized by tumor escape from both innate and adaptive immune responses, is now accepted as an important hallmark of cancer. Our research on breast cancer focuses on the active role that tumor infiltrating lymphocytes play in tumor progression and patient outcome. Toward this goal, we developed a methodology for the rapid isolation of intact lymphoid cells from normal and abnormal tissues in an effort to evaluate them proximate to their native state. Homogenates prepared using a mechanical dissociator show both increased viability and cell recovery while preserving surface receptor expression compared to enzyme-digested tissues. Furthermore, enzymatic digestion of the remaining insoluble material did not recover additional CD45+ cells indicating that quantitative and qualitative measurements in the primary homogenate likely genuinely reflect infiltrating subpopulations in the tissue fragment. The lymphoid cells in these homogenates can be easily characterized using immunological (phenotype, proliferation, etc.) or molecular (DNA, RNA and/or protein) approaches. CD45+ cells can also be used for subpopulation purification, in vitro expansion or cryopreservation. An additional benefit of this approach is that the primary tissue supernatant from the homogenates can be used to characterize and compare cytokines, chemokines, immunoglobulins and antigens present in normal and malignant tissues. This protocol functions extremely well for human breast tissues and should be applicable to a wide variety of normal and abnormal tissues.

This protocol describes the rapid non-enzymatic dissociation of fresh human tissue fragments for qualitative and quantitative assessment of CD45+ cells (lymphocytes/leukocytes) present in various normal and malignant human tissues. Additionally, the supernatant obtained from the primary tissue homogenate can be collected and stored for further analysis or experimentation.

The ability of malignant cells to evade the immune system, characterized by tumor escape from both innate and adaptive immune responses, is now accepted ...

Isolation and Flow Cytometric Characterization of Murine Small Intestinal Lymphocytes

The intestines &#8212; which contain the largest number of immune cells of any organ in the body &#8212; are constantly exposed to foreign antigens, both microbial and dietary. Given an increasing understanding that these luminal antigens help shape the immune response and that education of immune cells within the intestine is critical for a number of systemic diseases, there has been increased interest in characterizing the intestinal immune system. However, many published protocols are arduous and time-consuming. We present here a simplified protocol for the isolation of lymphocytes from the small-intestinal lamina propria, intraepithelial layer, and Peyer&#39;s patches that is rapid, reproducible, and does not require laborious Percoll gradients. Although the protocol focuses on the small intestine, it is also suitable for analysis of the colon. Moreover, we highlight some aspects that may need additional optimization depending on the specific scientific question. This approach results in the isolation of large numbers of viable lymphocytes that can subsequently be used for flow cytometric analysis or alternate means of characterization.

There is growing interest in the quantitative characterization of intestinal lymphocytes owing to increasing recognition that these cells play a critical role in a variety of intestinal and systemic diseases. In this protocol, we describe how to isolate single cell populations from different small-intestinal compartments for subsequent flow cytometric characterization.

The intestines &#8212; which contain the largest number of immune cells of any organ in the body &#8212; are constantly exposed to foreign antigens, both ...

Visualizing the Effects of Sputum on Biofilm Development Using a Chambered Coverglass Model

Biofilms consist of groups of bacteria encased in a self-secreted matrix. They play an important role in industrial contamination as well as in the development and persistence of many health related infections. One of the most well described and studied biofilms in human disease occurs in chronic pulmonary infection of cystic fibrosis patients. When studying biofilms in the context of the host, many factors can impact biofilm formation and development. In order to identify how host factors may affect biofilm formation and development, we used a static chambered coverglass method to grow biofilms in the presence of host-derived factors in the form of sputum supernatants. Bacteria are seeded into chambers and exposed to sputum filtrates. Following 48 hr of growth, biofilms are stained with a commercial biofilm viability kit prior to confocal microscopy and analysis. Following image acquisition, biofilm properties can be assessed using different software platforms. This method allows us to visualize key properties of biofilm growth in presence of different substances including antibiotics.

This protocol describes the visualization of biofilm development following exposure to host-factors using a slide chamber model. This model allows for direct visualization of biofilm development as well as analysis of biofilm parameters using computer software programs.

Biofilms consist of groups of bacteria encased in a self-secreted matrix. They play an important role in industrial contamination as well as in the ...

A High-throughput Platform for the Screening of Salmonella spp./Shigella spp.

Fecal-oral transmission of acute gastroenteritis occurs from time to time, especially when people who handled food and water are infected by Salmonella spp./Shigella spp. The gold standard method for the detection of Salmonella spp./Shigella spp. is direct culture but this is labor-intensive and time-consuming. Here, we describe a high-throughput platform for Salmonella spp./Shigella spp. screening, using real-time polymerase chain reaction (PCR) combined with guided culture. There are two major stages: real-time PCR and the guided culture. For the first stage (real-time PCR), we explain each step of the method: sample collection, pre-enrichment, DNA extraction and real-time PCR. If the real-time PCR result is positive, then the second stage (guided culture) is performed: selective culture, biochemical identification and serological characterization. We also illustrate representative results generated from it. The protocol described here would be a valuable platform for the rapid, specific, sensitive and high-throughput screening of Salmonella spp./Shigella spp.

A High-throughput Platform for the Screening of Salmonella spp./Shigella spp.

Salmonella spp./Shigella spp. are common pathogens attributed to diarrhea. Here, we describe a high-throughput platform for the screening of Salmonella spp./Shigella spp. using real-time PCR combined with guided culture.

Fecal-oral transmission of acute gastroenteritis occurs from time to time, especially when people who handled food and water are infected by Salmonella ...

Intravital Imaging of Intraepithelial Lymphocytes in Murine Small Intestine

Intraepithelial lymphocytes expressing &#947;&#948; T cell receptor (&#947;&#948; IEL) play a key role in immune surveillance of the intestinal epithelium. Due in part to the lack of a definitive ligand for the &#947;&#948; T cell receptor, our understanding of the regulation of &#947;&#948; IEL activation and their function in vivo remains limited. This necessitates the development of alternative strategies to interrogate signaling pathways involved in regulating &#947;&#948; IEL function and the responsiveness of these cells to the local microenvironment. Although &#947;&#948; IELs are widely understood to limit pathogen translocation, the use of intravital imaging has been critical to understanding the spatiotemporal dynamics of IEL/epithelial interactions at steady-state and in response to invasive pathogens. Herein, we present a protocol for visualizing IEL migratory behavior in the small intestinal mucosa of a GFP &#947;&#948; T cell reporter mouse using inverted spinning disk confocal laser microscopy. Although the maximum imaging depth of this approach is limited relative to the use of two-photon laser-scanning microscopy, spinning disk confocal laser microscopy provides the advantage of high speed image acquisition with reduced photobleaching and photodamage. Using 4D image analysis software, T cell surveillance behavior and their interactions with neighboring cells can be analyzed following experimental manipulation to provide additional insight into IEL activation and function within the intestinal mucosa.

We describe a method to visualize GFP-labeled &#947;&#948; IELs using intravital imaging of murine small intestine by inverted spinning disk confocal microscopy. This technique enables the tracking of live cells within the mucosa for up to 4 h and can be used to investigate a variety of intestinal immune-epithelial interactions. &#160;