This project was supported by Agriculture and Food Research Initiative Competitive Grant no. 2100-68003-30395 from the USDA National Institute of Food and Agriculture.

NOTE: All blood collection procedures were conducted in accordance with the guidelines set forth by the Appalachian State University (ASU) Institutional Review Board (IRB).
1. Whole Blood Collection
<ol>
	<li>Have a certified phlebotomist draw blood according to World Health Organization&#39;s guidelines.</li>
	<li>Draw blood into one 4 ml blood collection tube containing Di-Potassium Ethylenediaminetetraacetic acid (K2EDTA). Invert blood collection tube according to the manufactu...

<ol>
	<li>Cerwenka, A., Lanier, L. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Natural+killer+cells,+viruses+and+cancer.">Natural killer cells, viruses and cancer.</a> Nat Rev Immunol. 1 (1), 41-49 (2001).</li><li>Nieman, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exercise,+infection,+and+immunity.">Exercise, infection, and immunity.</a> Int J Sports Med. 15, 131-141 (1994).</li><li>Romeo, J., Warnberg, J., Pozo, T., Marcos, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physical+activity,+immunity+and+infection.">Physical activity, immunity and infection.</a> Proc Nutr Soc. 69 (3), 390-399 (2010).</li><li>Nieman, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Marathon+training+and+immune+function.">Marathon training and immune function.</a> Sports Med. 37 (4-5), 412-415 (2007).</li><li>Simpson, R. J., Kunz, H., Agha, N., Graff, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exercise+and+the+Regulation+of+Immune+Functions.">Exercise and the Regulation of Immune Functions.</a> Prog Mol Biol Transl Sci. 135, 355-380 (2015).</li><li>Walsh, N. P., 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=Position+statement.+Part+one:+Immune+function+and+exercise.">Position statement. Part one: Immune function and exercise.</a> Exerc Immunol Rev. 17, 6-63 (2011).</li><li>Timmons, B. W., Cieslak, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+natural+killer+cell+subsets+and+acute+exercise:+a+brief+review.">Human natural killer cell subsets and acute exercise: a brief review.</a> Exerc Immunol Rev. 14, 8-23 (2008).</li><li>Westermann, J., Pabst, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distribution+of+lymphocyte+subsets+and+natural+killer+cells+in+the+human+body.">Distribution of lymphocyte subsets and natural killer cells in the human body.</a> Clin Investig. 70 (7), 539-544 (1992).</li><li>Boyum, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+leucocytes+from+human+blood.+Further+observations.+Methylcellulose,+dextran,+and+ficoll+as+erythrocyteaggregating+agents.">Isolation of leucocytes from human blood. Further observations. Methylcellulose, dextran, and ficoll as erythrocyteaggregating agents.</a> Scand J Clin Lab Invest Suppl. 97, 31-50 (1968).</li><li>McMillan, R., Scott, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Leukocyte+labeling+with+51-Chromium.+I.+Technic+and+results+in+normal+subjects.">Leukocyte labeling with 51-Chromium. I. Technic and results in normal subjects.</a> Blood. 32 (5), 738-754 (1968).</li><li>Berk, L. S., 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+effect+of+long+endurance+running+on+natural+killer+cells+in+marathoners.">The effect of long endurance running on natural killer cells in marathoners.</a> Med Sci Sports Exerc. 22 (2), 207-212 (1990).</li><li>McAnulty, L. S., 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=Effect+of+blueberry+ingestion+on+natural+killer+cell+counts,+oxidative+stress,+and+inflammation+prior+to+and+after+2.5+h+of+running.">Effect of blueberry ingestion on natural killer cell counts, oxidative stress, and inflammation prior to and after 2.5 h of running.</a> Appl Physiol Nutr Metab. 36 (6), 976-984 (2011).</li><li>Millard, A. 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=Brief+Exercise+Increases+Peripheral+Blood+NK+Cell+Counts+without+Immediate+Functional+Changes,+but+Impairs+their+Responses+to+ex+vivo+Stimulation.">Brief Exercise Increases Peripheral Blood NK Cell Counts without Immediate Functional Changes, but Impairs their Responses to ex vivo Stimulation.</a> Front Immunol. 4, 125 (2013).</li><li>Janeway, C. A., Travers, P., Walport, M., Shlomchik, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Immunobiology: The Immune System in Health and Disease. 5th edn. , (2001).</li></ol>

The method described in this study directly measures the specific activity of an individual&#39;s NK cells in response to stimuli (in this particular case, prolonged exercise). Typically, NK cells are isolated from one&#39;s blood using density gradients or cell sorting by using a combination of markers. While these methods are widely used, they have many drawbacks: they are time consuming, involve multiple manipulations, and are heavily user dependent. As a result, undue stress is placed on the isolated NK cells, which ...

Natural killer cells are an essential element of the innate immune system. While they are very regulated, they have the capability to recognize and eliminate abnormal cells through cell-to-cell contact and without prior activation1. As such, they form a quick line of defense against infections. Exercise, especially intense, has been shown to transiently depress the immune system2,3,4,5. NK cells are particularly prone to this effect4,6,7, effectively creating a window of enhanced sensitivity to disease. Hence, the study of interventions before, during or after intense exercise with the goal of reducing its impact on NK cell function is of particular interest for the well-being of athletes post-competitions.
However, the study of such interventions is complicated by numerous factors: 1)&#160;NK cells are sparse8, at about 1% of the white blood cell compartment; 2)&#160;NK cells are very sensitive to stress and rely on constant exposure to physiological conditions to remain viable and stable during experimentation; and 3)&#160;standard assays to determine NK cell cytotoxicity, such as Ficoll gradients9 and release assays10, are unreliable and inconsistent. The inherent variability of human samples only compound these issues. Fresh human samples collected during interventions are fairly regulated and difficult to procure, at least when compared to animal samples or immortalized cell lines. This reduces opportunities to repeat experiments or add participants to the study cohort to reach significant statistical thresholds. Collectively, these issues support the need for a streamlined protocol that allows for both high-throughput and a high-reliability analysis of NK cell lytic activity in human samples.
We established a workflow that shortens the time necessary to identify, isolate and test NK cells from human whole blood while minimizing exposure to extraneous factors. The method optimizes the use of two instruments, a magnetic-based cell sorter and an imaging flow cytometer, and an assay-specific, optimized T:E ratio to allow the detection of decreases or increases of NK cell cytotoxicity.

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		<tr height="21">
			<td height="21" style="height:21px;width:371px;">K-562 lymphoblasts</td>
			<td style="width:183px;">ATCC</td>
			<td style="width:136px;">CCL-243</td>
			<td style="width:585px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Iscove&#39;s Modified Dulbecco&#39;s Media</td>
			<td style="width:183px;">ATCC</td>
			<td style="width:136px;">30-2005</td>
			<td>High glucose, with L-Glutamine, with HEPES, Sterile-filtered</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Alpha Minimum Essential medium</td>
			<td style="width:183px;">ATCC</td>
			<td style="width:136px;">CRL-2407</td>
			<td style="width:585px;">Without ribonucleosides and deoxyribonucleosides but with 2 mM L-glutamine and 1.5 g/L sodium bicarbonate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:371px;">Trypan Blue Solution 0.4%</td>
			<td style="width:183px;">Amresco</td>
			<td style="width:136px;">K940-100ML</td>
			<td>Tissue culture grade</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:371px;">Propridium Iodide Staining Solution</td>
			<td style="width:183px;">BD Pharmingen</td>
			<td style="width:136px;">51-66211E</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:371px;">Vybranto DiO cell-labeling solution</td>
			<td style="width:183px;">Vybranto</td>
			<td style="width:136px;">V-22886</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:371px;">autoMACS Pro Separator</td>
			<td style="width:183px;">Miltenyi Biotec</td>
			<td style="width:136px;">130-092-545</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:371px;">autoMACS Running Buffer</td>
			<td style="width:183px;">Miltenyi Biotec</td>
			<td style="width:136px;">130-091-221</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:371px;">autoMACS Washing Buffer</td>
			<td style="width:183px;">Miltenyi Biotec</td>
			<td style="width:136px;">130-092-987</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:371px;">autoMACS Columns</td>
			<td style="width:183px;">Miltenyi Biotec</td>
			<td style="width:136px;">130-021-101</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Whole Blood CD56 MicroBeads, human</td>
			<td style="width:183px;">Miltenyi Biotec</td>
			<td style="width:136px;">130-090-875</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">ImageStream X Mark II Imaging Flow Cytometer</td>
			<td style="width:183px;">EMD Millipore</td>
			<td style="width:136px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Speedbeads</td>
			<td style="width:183px;">Amnis Corporation</td>
			<td style="width:136px;">400030</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">0.4-0.7% Hypochlorite (Sterilizer)</td>
			<td style="width:183px;">VWR</td>
			<td>JT9416-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Coulter Clenz</td>
			<td style="width:183px;">Beckman Coulter</td>
			<td>8546929</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">70% Isopropanol (Debubbler)</td>
			<td style="width:183px;">EMD Millipore</td>
			<td style="width:136px;">1.3704</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">D-PBS (Sheath fluid)</td>
			<td style="width:183px;">EMD Millipore</td>
			<td style="width:136px;">BSS-1006-B (1X)</td>
			<td>No calcium or magnesium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">INSPIRE Software</td>
			<td style="width:183px;">EMD Millipore</td>
			<td style="width:136px;"></td>
			<td>Version Mark II, September 2013</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ideas Application Software</td>
			<td style="width:183px;">EMD Millipore</td>
			<td style="width:136px;"></td>
			<td>Version 6.1, July 2014</td>
		</tr>
	</tbody>
</table>

flow cytometric analysis of natural killer cell lytic activity in human whole blood

NK cell cytotoxicity is a widely used measure to determine the effect of outside intervention on NK cell function. However, the accuracy and reproducibility of this assay can be considered unstable, either because of user&#39;s errors or because of the sensitivity of NK cells to experimental manipulation. To eliminate these issues, a workflow that reduces them to a minimum was established and is presented here. To illustrate, we obtained blood samples, at various time points, from runners (n = 4) that were submitted to an intense bout of exercise. First, NK cells are simultaneously identified and isolated through CD56 tagging and magnetic-based sorting, directly from whole blood and from as little as one milliliter. The sorted NK cells are removed of any reagent or capping antibodies. They can be counted in order to establish an accurate NK cell count per milliliter of blood. Secondly, the sorted NK cells (effectors cells or E) can be mixed with 3,3&#39;-Diotadecyloxacarbocyanine Perchlorate (DiO) tagged K562 cells (target cells or T) at an assay-optimal 1:5 T:E ratio, and analyzed using an imaging flow-cytometer that allows for the visualization of each event and the elimination of any false positive or false negatives (such as doublets or effector cells). This workflow can be completed in about 4 h, and allows for very stable results even when working with human samples. When available, research teams can test several experimental interventions in human subjects, and compare measurements across several time points without compromising the data&#39;s integrity.

Determination of NK cell count 
The effect of heavy running on NK cell count in whole blood was measured, using the exercise protocol described in Figure 2. Blood samples were drawn before exercise, immediately after exercise, 1.5 h after exercise, and finally 24 and 48 h after the initial blood draw. The concentration of NK cells per milliliter of whole blood was measured for each runner (Figure 3A) and on average (Figure 3B) for ea...

Watch this Scientific Journal Video about Flow Cytometric Analysis of Natural Killer Cell Lytic Activity in Human Whole Blood at JoVE.com

Flow Cytometric Analysis of Natural Killer Cell Lytic Activity in Human Whole Blood

This work describes an advanced workflow for the accurate and fast determination of NK (Natural Killer) cell count and NK cell cytotoxicity in human blood samples.

NK cell cytotoxicity is a widely used measure to determine the effect of outside intervention on NK cell function. However, the accuracy and ...

The overall goal of this experiment is to determine NK cell count and cytotoxic activation levels in a human whole blood sample in a fast, reliable and stable manner. This method can help answer questions in the immunological fields, such as, What are the effects of outside interventions on the bioactivity of NK cells? The main advantage of this technique is that it is fast and accurate, While still providing reproducible results across experiments.To isolate NK cells from human whole blood, first place 15 milliliter tubes labeled Whole blood sample, Negative Fraction and Positive Fraction into the appropriate positions in the cell separator tube rack. When all of the tubes are loaded, insert the separator rack onto the mini-sampler for auto labeling, and select Reagent on the menu, to highlight the position where the vial will be placed on the rack. Select Read Reagent to activate the 2D code reader and hold the appropriate reagent vial in front of the 2D code reader at an angle 0.5 to 2.5 centimeters from the code reader cover.Place the read vial into the appropriate separator rack position. Next, under the Separation tab, highlight the desired positions. Then open the Labeling submenu and select an auto-labeling program.Assign the cell separation reagent microbeads to rack positions 1, 2, 3 and 4. And select the Posselwb separaton program. Select the Rinse Wash program.Enter 1500 microliters for the Sample Volume under the Volume sub menu, and press Enter. Then click Run to begin the cell separation. Clicking okay to confirm that enough buffer is available for processing all of the samples.To prepare a Cytotoxicity Assay sample, first, label 1.5 milliliter tubes for each sample and/or participant as appropriate, and pipe out the desired ratio of NK cells and DIO labeled K562 cells into each tube. Collect the cells by centrifugation, and carefully remove the supernatant without disturbing the cell pellet. Next, resuspend the cell mixture in 500 microliters of incomplete NK cell medium, and label the cells in each tube with 5 microliters of propidium iodide.Collect the cells via another centrifugation, and incubate the cull culture at 37 degrees celsius for two hours. At the end of the incubation, centrifuge the cells under the same centrifuge conditions, and resuspend the pellet in 25 microliters of fresh incomplete NK cell culture medium. To analyze the cells by Flow Cytometry, first, click the start up button in the imaging flow cytometer software to flush the system.Next, click on the scatterplot button to create four scatterplots, and load the double positive control tube. Using the double positive control sample, determine the desired intensity for the 405 milliwatt laser, so that the detector is not overloaded, and set the imager to acquire the appropriate number of cell counts. Setting the 405 milliwatt laser at an intensity that is suitable for the detection of both DIO and PI will require experience with both dyes and the detection range of the flow cytometer.After the acquisition of the double positive control sample finishes, load the DIO only control sample, select the 40X objective, and turn off the 642 milliwatt laser and the Brightfield channel. Breed the appropriate number of cells and repeat the acquisition for the propidium iodide only sample. When all of the control samples have been run, turn the 405 milliwatt laser and Brightfield channel, back on, and click Set Intensity.Then, under the File Acquisition tab, enter a custom file name, and select a folder for saving the data files. Next, enter the number of cells to acquire. Load the first experimental sample tube and click the Acquire button.When all of the samples have been run, open the imaging flow cytometer analysis software application, and open a single experimental RIF file. Under the compensation tab, select Create New Matrix. The software will prompt for the selection of the single color files, and merge them to create a matrix file to be selected for applying the channel compensation.Use the Building Blocks function to set up the appropriate dot plots. Then click on the statistics function to access the cell numbers in each gate. In this representative experiment, blood samples were drawn as indicated and the concentration of NK cells per milliliter of whole blood was measured for each runner, and on average for each time point.Three out of four runners presented a similar slight increase in NK cell count after exercise. Immediately followed by a sharp decrease, before slowly returning to normal, 24 to 48 hours after the end of the event. On average the NK cell count decreased 1.5 hours after exercise, but returned to near normal levels after 24 hours.After calculating the cell count, the cytotoxic activity of the NK cells was immediately analyzed as just demonstrated, with an average decrease in NK cell cytotoxicity immediately, and 1.5 hours after the termination of the exercise event, that increased significantly by 24 hours post exercise. The NK cytotoxicity remained high compared to the pre-exercise levels, albeit nonsignificantly. Once mastered, this technique can be completed in about four hours when performed properly.After watching this video, you should have a good understanding of how to obtain and characterize NK cells count and cytotoxic activity from human blood samples in a reproducible hydropic manner.

flow-cytometric-analysis-natural-killer-cell-lytic-activity-human

Research

JoVE Journal

Immunology and Infection

12.2K ビュー.  North Carolina A&T State University, North Carolina Research Campus. The overall goal of this experiment is to determine NK cell count and cytotoxic activation levels in a human whole blood sample in a fast, reliable and stable manner. This method can help answer questions in the immunological fields, such as, What are the effects of outside interventions on the bioactivity of NK cells? The main advantage of this technique is that it is fast and accurate, While still providing reproducible results across experiments.To isolate NK cells from human whole ...

ビデオ: Flow Cytometric Analysis of Natural Killer Cell Lytic Activity in Human Whole Blood

Super-resolution Imaging of the Natural Killer Cell Immunological Synapse on a Glass-supported Planar Lipid Bilayer

The glass-supported planar lipid bilayer system has been utilized in a variety of disciplines. One of the most useful applications of this technique has been in the study of immunological synapse formation, due to the ability of the glass-supported planar lipid bilayers to mimic the surface of a target cell while forming a horizontal interface. The recent advances in super-resolution imaging have further allowed scientists to better view the fine details of synapse structure. In this study, one of these advanced techniques, stimulated emission depletion (STED), is utilized to study the structure of natural killer (NK) cell synapses on the supported lipid bilayer. Provided herein is an easy-to-follow protocol detailing: how to prepare raw synthetic phospholipids for use in synthesizing glass-supported bilayers; how to determine how densely protein of a given concentration occupies the bilayer's attachment sites; how to construct a supported lipid bilayer containing antibodies against NK cell activating receptor CD16; and finally, how to image human NK cells on this bilayer using STED super-resolution microscopy, with a focus on distribution of perforin positive lytic granules and filamentous actin at NK synapses. Thus, combining the glass-supported planar lipid bilayer system with STED technique, we demonstrate the feasibility and application of this combined technique, as well as intracellular structures at NK immunological synapse with super-resolution.

We describe here a combination of the glass-supported lipid bilayer technique of forming immunological synapses with the super-resolution imaging technique of stimulated emission depletion (STED) microscopy. The goal of this protocol is to provide users with the instructions necessary to successfully carry out these two techniques.

The glass-supported planar lipid bilayer system has been utilized in a variety of disciplines. One of the most useful applications of this technique has ...

Whole-animal Imaging and Flow Cytometric Techniques for Analysis of Antigen-specific CD8+ T Cell Responses after Nanoparticle Vaccination

Traditional vaccine adjuvants, such as alum, elicit suboptimal CD8+ T cell responses. To address this major challenge in vaccine development, various nanoparticle systems have been engineered to mimic features of pathogens to improve antigen delivery to draining lymph nodes and increase antigen uptake by antigen-presenting cells, leading to new vaccine formulations optimized for induction of antigen-specific CD8+ T cell responses. In this article, we describe the synthesis of a &#8220;pathogen-mimicking&#8221; nanoparticle system, termed interbilayer-crosslinked multilamellar vesicles (ICMVs) that can serve as an effective vaccine carrier for co-delivery of subunit antigens and immunostimulatory agents and elicitation of potent cytotoxic CD8+ T lymphocyte (CTL) responses. We describe methods for characterizing hydrodynamic size and surface charge of vaccine nanoparticles with dynamic light scattering and zeta potential analyzer and present a confocal microscopy-based procedure to analyze nanoparticle-mediated antigen delivery to draining lymph nodes. Furthermore, we show a new bioluminescence whole-animal imaging technique utilizing adoptive transfer of luciferase-expressing, antigen-specific CD8+ T cells into recipient mice, followed by nanoparticle vaccination, which permits non-invasive interrogation of expansion and trafficking patterns of CTLs in real time. We also describe tetramer staining and flow cytometric analysis of peripheral blood mononuclear cells for longitudinal quantification of endogenous T cell responses in mice vaccinated with nanoparticles.

We describe whole-animal imaging and flow cytometry-based techniques for monitoring expansion of antigen-specific CD8+ T cells in response to immunization with nanoparticles in a murine model of vaccination.

Traditional vaccine adjuvants, such as alum, elicit suboptimal CD8+ T cell responses. To address this major challenge in vaccine development, various ...

Isolation and Flow Cytometric Analysis of Immune Cells from the Ischemic Mouse Brain

Ischemic stroke initiates a robust inflammatory response that starts in the intravascular compartment and involves rapid activation of brain resident cells. A key mechanism of this inflammatory response is the migration of circulating immune cells to the ischemic brain facilitated by chemokine release and increased endothelial adhesion molecule expression. Brain-invading leukocytes are well-known contributing to early-stage secondary ischemic injury, but their significance for the termination of inflammation and later brain repair has only recently been noticed.
Here, a simple protocol for the efficient isolation of immune cells from the ischemic mouse brain is provided. After transcardial perfusion, brain hemispheres are dissected and mechanically dissociated. Enzymatic digestion with Liberase&#160;is followed by density gradient (such as Percoll) centrifugation to remove myelin and cell debris. One major advantage of this protocol is the single-layer density gradient procedure which does not require time-consuming preparation of gradients and can be reliably performed. The approach yields highly reproducible cell counts per brain hemisphere and allows for measuring several flow cytometry panels in one biological replicate. Phenotypic characterization and quantification of brain-invading leukocytes after experimental stroke may contribute to a better understanding of their multifaceted roles in ischemic injury and repair.

Inflammation plays a central role in the pathogenesis of ischemic stroke. Increasing evidence suggests that it acts as a double-edged sword which exacerbates early brain injury, but also contributes to later repair. This protocol describes the isolation of immune cells from the ischemic brain and their subsequent flow cytometric phenotyping.

Ischemic stroke initiates a robust inflammatory response that starts in the intravascular compartment and involves rapid activation of brain resident ...

Isolation and Flow Cytometric Analysis of Glioma-infiltrating Peripheral Blood Mononuclear Cells

Our laboratory has recently demonstrated that natural killer (NK) cells are capable of eradicating orthotopically implanted mouse GL26 and rat CNS-1 malignant gliomas soon after intracranial engraftment if the cancer cells are rendered deficient in their expression of the &#946;-galactoside-binding lectin galectin-1 (gal-1). More recent work now shows that a population of Gr-1+/CD11b+ myeloid cells is critical to this effect. To better understand the mechanisms by which NK and myeloid cells cooperate to confer gal-1-deficient tumor rejection we have developed a comprehensive protocol for the isolation and analysis of glioma-infiltrating peripheral blood mononuclear cells (PBMC). The method is demonstrated here by comparing PBMC infiltration into the tumor microenvironment of gal-1-expressing GL26 gliomas with those rendered gal-1-deficient via shRNA knockdown. The protocol begins with a description of&#160;how to culture and prepare GL26 cells for inoculation into the syngeneic C57BL/6J mouse brain. It then explains the steps involved in the isolation and flow cytometric analysis of glioma-infiltrating PBMCs from the early brain tumor microenvironment. The method is adaptable to a number of in vivo experimental designs in which temporal data on immune infiltration into the brain is required. The method is sensitive and highly reproducible, as glioma-infiltrating PBMCs can be isolated from intracranial tumors as soon as 24 hr post-tumor engraftment with similar cell counts observed from time point matched tumors throughout independent experiments. A single experimentalist can perform the method from brain harvesting to flow cytometric analysis of glioma-infiltrating PBMCs in roughly 4-6 hr depending on the number of samples to be analyzed. Alternative glioma models and/or cell-specific detection antibodies may also be used at the experimentalists&#8217; discretion to assess the infiltration of several other immune cell types of interest without the need for alterations to the overall procedure.

Presented here is a straightforward method for the isolation and flow cytometric analysis of glioma-infiltrating peripheral blood mononuclear cells that yields time-dependent quantitative data on the number and activation status of immune cells entering the early brain tumor microenvironment.

Our laboratory has recently demonstrated that natural killer (NK) cells are capable of eradicating orthotopically implanted mouse GL26 and rat CNS-1 ...

A Simple Flow Cytometric Method to Measure Glucose Uptake and Glucose Transporter Expression for Monocyte Subpopulations in Whole Blood

Monocytes are innate immune cells that can be activated by pathogens and inflammation associated with certain chronic inflammatory diseases. Activation of monocytes induces effector functions and a concomitant shift from oxidative to glycolytic metabolism that is accompanied by increased glucose transporter expression. This increased glycolytic metabolism is also observed for trained immunity of monocytes, a form of innate immunological memory. Although in vitro protocols examining glucose transporter expression and glucose uptake by monocytes have been described, none have been examined by multi-parametric flow cytometry in whole blood. We describe a multi-parametric flow cytometric protocol for the measurement of fluorescent glucose analog 2-NBDG uptake in whole blood by total monocytes and the classical (CD14++CD16-), intermediate (CD14++CD16+) and non-classical (CD14+CD16++) monocyte subpopulations. This method can be used to examine glucose transporter expression and glucose uptake for total monocytes and monocyte subpopulations during homeostasis and inflammatory disease, and can be easily modified to examine glucose uptake for other leukocytes and leukocyte subpopulations within blood.

Monocytes are integral components of the human innate immune system that rely on glycolytic metabolism when activated. We describe a flow cytometry protocol to measure glucose transporter expression and glucose uptake by total monocytes and monocyte subpopulations in fresh whole blood.

Monocytes are innate immune cells that can be activated by pathogens and inflammation associated with certain chronic inflammatory diseases. Activation of ...

Flow Cytometric Analysis of Particle-bound Bet v 1 Allergen in PM10

Flow cytometry is a method widely used to quantify suspended solids such as cells or bacteria in a size range from 0.5 to several tens of micrometers in diameter. In addition to a characterization of forward and sideward scatter properties, it enables the use of fluorescent labeled markers like antibodies to detect respective structures. Using indirect antibody staining, flow cytometry is employed here to quantify birch pollen allergen (precisely Bet v 1)-loaded particles of 0.5 to 10 &#181;m in diameter in inhalable particulate matter (PM10, particle size &#8804;10 &#181;m in diameter). PM10 particles may act as carriers of adsorbed allergens possibly transporting them to the lower respiratory tract, where they could trigger allergic reactions.
So far the allergen content of PM10 has been studied by means of enzyme linked immunosorbent assays (ELISAs) and scanning electron microscopy. ELISA measures the dissolved and not the particle-bound allergen. Compared to scanning electron microscopy, which can visualize allergen-loaded particles, flow cytometry may additionally quantify them. As allergen content of ambient air can deviate from birch pollen count, allergic symptoms might perhaps correlate better with allergen exposure than with pollen count. In conjunction with clinical data, the presented method offers the opportunity to test in future experiments whether allergic reactions to birch pollen antigens are associated with the Bet v 1 allergen content of PM10 particles &#62;0.5 &#181;m.

Here, we present a protocol to quantify allergen-loaded particles by flow cytometry. Ambient particulate matter particles may act as carriers of adsorbed allergens. We show here that flow cytometry, a method widely used to characterize suspended solids &#62;0.5 &#181;m in diameter, can be used to measure these allergen-loaded particles.

Flow cytometry is a method widely used to quantify suspended solids such as cells or bacteria in a size range from 0.5 to several tens of micrometers in ...

Isolation and Flow Cytometric Analysis of Human Endocervical Gamma Delta T Cells

The female reproductive tract (FRT) mucosal immune system serves as the first line of defense. Better knowledge of the genital mucosa is therefore essential for understanding pathogenicity of different pathogens including HIV. Gamma delta (GD) T cells are the prototype of &#39;unconventional&#39; T cells and represent a relatively small subset of T cells defined by their expression of heterodimeric T-cell receptors (TCRs) composed of gamma and delta chains. This sets them apart from the classical and much better known CD4+ helper T cells and CD8+ cytotoxic T cells that are defined by alpha-beta TCRs. GD T cells often show tissue-specific localization and are enriched in epithelium. GD T cells orchestrate immune responses in inflammation, tumor surveillance, infectious disease, and autoimmunity.
Here, we present a method to reproducibly isolate and analyze human endocervical intraepithelial GD T lymphocytes. We have used endocervical cytobrush samples from women participating in the Women&#39;s Interagency HIV Infection Study (WIHS). Knowledge about GD T cells interactions during conditions in which there is an insult to the vaginal mucosal could be applied to any clinical study in which mucosal vulnerability is addressed, including the development of vaginal microbicides.In addition, knowledge about mucosal GD T cell responses has potential for application of GD T cell-based immune therapy in treating infectious diseases.

We describe here an isolation method to obtain human endocervical intraepithelial lymphocytes for the analysis of intraepithelial gamma delta T cells. This protocol can be extended for the purification of endocervical gamma delta T cells by magnetic beads or by cell sorting.

The female reproductive tract (FRT) mucosal immune system serves as the first line of defense. Better knowledge of the genital mucosa is therefore ...

Dextran Enhances the Lentiviral Transduction Efficiency of Murine and Human Primary NK Cells

The efficient transduction of specific genes into natural killer (NK) cells has been a major challenge. Successful transductions are critical to defining the role of the gene of interest in the development, differentiation, and function of NK cells. Recent advances related to chimeric antigen receptors (CARs) in cancer immunotherapy accentuate the need for an efficient method to deliver exogenous genes to effector lymphocytes. The efficiencies of lentiviral-mediated gene transductions into primary human or mouse NK cells remain significantly low, which is a major limiting factor. Recent advances using cationic polymers, such as polybrene, show an improved gene transduction efficiency in T cells. However, these products failed to improve the transduction efficiencies of NK cells. This work shows that dextran, a branched glucan polysaccharide, significantly improves the transduction efficiency of human and mouse primary NK cells. This highly reproducible transduction methodology provides a competent tool for transducing human primary NK cells, which can vastly improve clinical gene delivery applications and thus NK cell-based cancer immunotherapy.

The goal of this study was to formulate technologies that allow for successful gene transduction in primary natural killer (NK) cells. The dextran-mediated lentiviral transduction of human or mouse primary NK cells results in higher gene expression efficiencies. This method of gene transduction will vastly improve NK cell genetic manipulation.

The efficient transduction of specific genes into natural killer (NK) cells has been a major challenge. Successful transductions are critical to defining ...

Characterization of Human Monocyte Subsets by Whole Blood Flow Cytometry Analysis

Monocytes are key contributors in various inflammatory disorders and alterations to these cells, including their subset proportions and functions, can have pathological significance. An ideal method for examining alterations to monocytes is whole blood flow cytometry as the minimal handling of samples by this method limits artifactual cell activation. However, many different approaches are taken to gate the monocyte subsets leading to inconsistent identification of the subsets between studies. Here we demonstrate a method using whole blood flow cytometry to identify and characterize human monocyte subsets (classical, intermediate, and non-classical). We outline how to prepare the blood samples for flow cytometry, gate the subsets (ensure contaminating cells have been removed), and determine monocyte subset expression of surface markers &#8212; in this example M1 and M2 markers. This protocol can be extended to other studies that require a standard gating method for assessing monocyte subset proportions and monocyte subset expression of other functional markers.

Here we present a protocol for characterizing monocyte subsets by whole blood flow cytometry. This includes outlining how to gate the subsets and assess their expression of surface markers and giving an example of the assessment of the expression of M1 (inflammatory) and M2 markers (anti-inflammatory).

Monocytes are key contributors in various inflammatory disorders and alterations to these cells, including their subset proportions and functions, can ...

Measuring Phagocytosis of Aspergillus fumigatus Conidia by Human Leukocytes using Flow Cytometry

Invasive pulmonary infection by the mold Aspergillus fumigatus poses a great threat to immunocompromised patients. Inhaled fungal conidia (spores) are cleared from the human lung alveoli by being phagocytosed by innate monocytes and/or neutrophils. This protocol offers a fast and reliable measurement of phagocytosis by flow cytometry using fluorescein isothiocyanate (FITC)-labeled conidia for co-incubation with human leukocytes and subsequent counterstaining with an anti-FITC antibody to allow discrimination of internalized and cell-adherent conidia. Major advantages of this protocol are its rapidness, the possibility to combine the assay with cytometric analysis of other cell markers of interest, the simultaneous analysis of monocytes and neutrophils from a single sample and its applicability to other cell wall-bearing fungi or bacteria. Determination of percentages of phagocytosing leukocytes provides a means to microbiologists for evaluating virulence of a pathogen or for comparing pathogen wildtypes and mutants as well as to immunologists for investigating human leukocyte capabilities to combat pathogens.

Measuring Phagocytosis of Aspergillus fumigatus Conidia by Human Leukocytes using Flow Cytometry

This protocol provides a fast and reliable method to quantitatively measure phagocytosis of Aspergillus fumigatus conidia by human primary phagocytes using flow cytometry and to discriminate phagocytosis of conidia from mere adhesion to leukocytes.

Invasive pulmonary infection by the mold Aspergillus fumigatus poses a great threat to immunocompromised patients. Inhaled fungal conidia (spores) are ...