Name: reliable and high efficiency extraction of kidney immune cells
Uploaded: 2016-08-19T13:00:00
Description: Watch this Scientific Journal Video about Reliable and High Efficiency Extraction of Kidney Immune Cells at JoVE.com

This work is supported by a Research Grant from Dialysis Clinics Inc. and from the University of Missouri Research Board Grant.

All protocol steps performed were reviewed and approved by the University of Missouri Animal Care and Use Committee (ACUC). For this protocol, male C57Bl/6 mice aged 15 weeks were utilized although theoretically any rodent at any age can be used for experiments. Since, this is a non-survival surgery, euthanasia is achieved by exsanguination and bilateral&#160;pneumothorax.
1. Perfusion of the Kidneys&#160;
Note: Perfusion of organs such as heart, liver and kidney remo...

<ol>
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Immunol. 177 (5), 3380-3387 (2006).</li><li>Ascon, 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=Renal+ischemia-reperfusion+leads+to+long+term+infiltration+of+activated+and+effector-memory+T+lymphocytes.">Renal ischemia-reperfusion leads to long term infiltration of activated and effector-memory T lymphocytes.</a> Kidney Int. 75 (5), 526-535 (2009).</li><li>Belliere, J., 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=Specific+macrophage+subtypes+influence+the+progression+of+rhabdomyolysis-induced+kidney+injury.">Specific macrophage subtypes influence the progression of rhabdomyolysis-induced kidney injury.</a> J. Am. Soc. Nephrol. 26 (6), 1363-1377 (2015).</li><li>Chen, Z., 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=Collagenase+digestion+down-regulates+the+density+of+CD27+on+lymphocytes.">Collagenase digestion down-regulates the density of CD27 on lymphocytes.</a> J. Immunol. Methods. 413, 57-61 (2014).</li><li>Dong, X., 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=Resident+dendritic+cells+are+the+predominant+TNF-secreting+cell+in+early+renal+ischemia-reperfusion+injury.">Resident dendritic cells are the predominant TNF-secreting cell in early renal ischemia-reperfusion injury.</a> Kidney Int. 71 (7), 619-628 (2007).</li><li>Hickey, F. B., Martin, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diabetic+kidney+disease+and+immune+modulation.">Diabetic kidney disease and immune modulation.</a> Curr. Opin. Pharmacol. , (2013).</li><li>Kawakami, T., 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=Resident+renal+mononuclear+phagocytes+comprise+five+discrete+populations+with+distinct+phenotypes+and+functions.">Resident renal mononuclear phagocytes comprise five discrete populations with distinct phenotypes and functions.</a> J. Immunol. 191 (6), 3358-3372 (2013).</li><li>Liu, X., 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=Isolating+glomeruli+from+mice:+A+practical+approach+for+beginners.">Isolating glomeruli from mice: A practical approach for beginners.</a> Exp. Ther. Med. 5 (5), 1322-1326 (2013).</li><li>Picot, J., Guerin, C. L., Le Van, K. C., Boulanger, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow+cytometry:+retrospective,+fundamentals+and+recent+instrumentation.">Flow cytometry: retrospective, fundamentals and recent instrumentation.</a> Cytotechnology. 64 (2), 109-130 (2012).</li><li>Ricardo, S. D., van, G. H., Eddy, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macrophage+diversity+in+renal+injury+and+repair.">Macrophage diversity in renal injury and repair.</a> J. Clin. Invest. 118 (11), 3522-3530 (2008).</li><li>Rodriguez-Iturbe, B., Pons, H., Herrera-Acosta, J., Johnson, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+immunocompetent+cells+in+nonimmune+renal+diseases.">Role of immunocompetent cells in nonimmune renal diseases.</a> Kidney Int. 59 (5), 1626-1640 (2001).</li><li>Vielhauer, V., 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=Efficient+renal+recruitment+of+macrophages+and+T+cells+in+mice+lacking+the+duffy+antigen/receptor+for+chemokines.">Efficient renal recruitment of macrophages and T cells in mice lacking the duffy antigen/receptor for chemokines.</a> Am. J. Pathol. 175 (1), 119-131 (2009).</li><li>Weisheit, C. K., Engel, D. R., Kurts, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendritic+Cells+and+Macrophages:+Sentinels+in+the+Kidney.">Dendritic Cells and Macrophages: Sentinels in the Kidney.</a> Clin. J. Am. Soc. Nephrol. , (2015).</li><li>Williams, S. K., McKenney, S., Jarrell, B. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collagenase+lot+selection+and+purification+for+adipose+tissue+digestion.">Collagenase lot selection and purification for adipose tissue digestion.</a> Cell Transplant. 4 (3), 281-289 (1995).</li><li>Yamamoto, T., 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=Deterioration+and+variability+of+highly+purified+collagenase+blends+used+in+clinical+islet+isolation.">Deterioration and variability of highly purified collagenase blends used in clinical islet isolation.</a> Transplantation. 84 (8), 997-1002 (2007).</li><li>Zhou, J., Nagarkatti, P., Zhong, Y., Nagarkatti, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immune+modulation+by+chondroitin+sulfate+and+its+degraded+disaccharide+product+in+the+development+of+an+experimental+model+of+multiple+sclerosis.">Immune modulation by chondroitin sulfate and its degraded disaccharide product in the development of an experimental model of multiple sclerosis.</a> J. 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We have presented here a methodology to obtain immune cells from the kidney in a reliable and efficient manner. The major modification to the widely used collagenase digestion step (mechanical disruption of tissue) saves about 30 min and the isolation of a large number of viable immune cells takes under two hours for 4 kidney samples. Moreover, depending on our research question, we now only use a single kidney (the other kidney can be used for protein analysis by Western blots, immunohistochemistry and mRNA analysis by ...

Immune system activation occurs in multiple kidney diseases and pathophysiological processes 6,10,11,13. Potential areas of active research encompass the various triggers for immune system activation, various cell types involved, the cytokine/chemokine pattern in a particular disease setting, modulation of all of the aforementioned processes by a particular drug etc. To exemplify, in ischemia-reperfusion injury (a model for acute kidney injury), there is an increase in immune cells or bone-marrow derived hematopoietic cells or CD45+ cells within a few hours, which is sustained through the period of repair or fibrosis (6 weeks later) 5,12. These immune cells secrete both pro-inflammatory and anti-inflammatory cytokines and chemokines to orchestrate the process of repair 5,12. Currently, the ability to use multiple fluorophores simultaneously to label cell populations in a single cell suspension has increased with the advent of modern flow cytometry machines with four to five lasers. This has substantially added to the capability to discriminate the cell populations based on their functional status 3,7. For example, to accurately label a macrophage as F4/80lowCD11bhighLy6bhighCD206low, at least 3 more fluorophores would be needed in the same sample volume to gate for live cells, CD45+ (leukocytes) and Ly6G- (neutrophils) and this is very much possible with the newer Flow Cytometers 3. However, the downstream assays for cytokine secretion, cell proliferation, cytotoxicity, macrophage activation and the quantification of numbers of various subsets of lymphocytes and monocytes not only needs good quality (live cells, singlets) but adequate numbers of cells.
The immune system in the kidney is made up of both adaptive and innate components and multiple cell types 1,7,13. For example, in mice the two kidneys together are reported to contain 2-17% (28,000-266,000) CD45+ cells of the total kidney immune cells isolated (1.4 x 106 cells) and about 5-15% (1,400-4,200) of these are CD4+ cells 1,5,12. A small percentage (5-15%, 70-630) of these CD4+ cells are FoxP3+ cells (Figure 1)1. Due to these step wise reductions in percentages of cells, sometimes the cell population of interest (in this case CD45+CD4+FoxP3+ cells) is represented by a mere ~100 cells. The small number of CD45+CD4+FoxP3+ cells makes it imperative that a large number of total cells are isolated and the cells are of good quality for downstream studies such as cytokine secretion assays. Moreover, it may be necessary to combine kidneys from 2-3 mice since the subpopulations are not represented in high enough numbers to perform quantifiable assays. Hence, reliable and efficient isolation of kidney mononuclear cell populations is desirable in order to study the immunological spectrum associated with kidney diseases.
Traditionally, for isolation of kidney mononuclear cells, investigators have used a variety of enzymatic digestions such as collagenase 1A or II including DNase 1 1,5,12. It is well known that collagenases have enzymatic activity that varies with lot numbers and by company of manufacture, necessitating titration for the optimum concentration and duration of incubation 4,14,15. In addition, digestion with collagenase adds time for mincing the kidney into small pieces, necessitates incubation of the kidney pieces in a heated (37 &#176;C) bath and additional time for incubation in EDTA for stopping the reaction. In addition, less sterility may be achieved for some downstream procedures needing cell culture. More importantly, depending on the investigator and all the variables involved, it leads to variability in the data and interpretation across laboratories. Recently, with the development of mechanical tissue disruptors/homogenizers 16, the collagenase digestion step is completely avoided and replaced by a simple mechanical disruption of the kidneys 2. Herein, we demonstrate a simple yet efficient method for the isolation of kidney immune cells for everyday immune cell extractions. Importantly, this technique can be adapted to other soft and non-fibrous tissues such as the liver and brain 16.

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			<td>Stomacher 80 Biomaster lab system</td>
			<td>Seward</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Stomacher 80 Classic bags</td>
			<td>Seward</td>
			<td>BA6040/STR</td>
			<td></td>
		</tr>
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			<td>Sorvall Legend XFR Centrifuge</td>
			<td>Thermo Scientific</td>
			<td></td>
			<td>Or equivalent equipment&#160;</td>
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			<td>Hemocytometer</td>
			<td>Electron Microscopy Sciences</td>
			<td>63514-11</td>
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			<td>Analytical flow cytometer</td>
			<td>BD LSR-X20 Fortessa</td>
			<td></td>
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			<td>Percoll&#160;</td>
			<td>Sigma</td>
			<td>P1644</td>
			<td></td>
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			<td>Dulbecco&#8217;s phosphate buffered saline 1X (DPBS)</td>
			<td>Gibco, Life Technologies</td>
			<td>14190-250</td>
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			<td>Polypropylene tubes, no cap</td>
			<td>Becton Dickinson</td>
			<td>352002</td>
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			<td>Fixable Viability Stain</td>
			<td>BD Biosciences&#160;</td>
			<td>FVS510,&#160; 564406</td>
			<td></td>
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			<td>Anti-CD16/32 (Clone: 93)</td>
			<td>EBioscience</td>
			<td>14-0161</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-CD45 (clone: 30-F11)&#160; BV421&#160;</td>
			<td>BD Pharmingen</td>
			<td>103133/4</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Foxp3 (Clone: FJK-16s) APC</td>
			<td>EBioscience</td>
			<td>17-5773</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-CD127 (Clone: A7R34) PE/Cy7</td>
			<td>Biolegend</td>
			<td>135013/4</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-CD44 (Clone: IM7) PerCP/Cy5.5</td>
			<td>Biolegend</td>
			<td>103031/2</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-CD4 (Clone: RM4-5) APC-Cy7</td>
			<td>Biolegend</td>
			<td>100413/4</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-CD8 (Clone: 53-6.7) BV785</td>
			<td>Biolegend</td>
			<td>100749/50</td>
			<td></td>
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		<tr>
			<td>Anti-Ly6G (Clone: 1A8) FITC</td>
			<td>Biolegend</td>
			<td>127605/6</td>
			<td></td>
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			<td>Anti-CD11b (Clone: M1/70) PerCP-Cy5.5</td>
			<td>Biolegend</td>
			<td>101227/8</td>
			<td></td>
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			<td>Anti-F4/80 (Clone: BM8) APC</td>
			<td>Biolegend</td>
			<td>123115/6</td>
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			<td>Anti-CD11c (Clone: N418) BV785</td>
			<td>Biolegend</td>
			<td>117335/6</td>
			<td></td>
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			<td>Anti-CD301 (Clone: LOM-14) PE-Cy7</td>
			<td>Biolegend</td>
			<td>145705/6</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-CD26 (Clone: H194-112) PE</td>
			<td>Biolegend</td>
			<td>137803/4</td>
			<td></td>
		</tr>
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			<td>100 &#956;m filter&#160;</td>
			<td>Fisher Scientific</td>
			<td>22363548</td>
			<td></td>
		</tr>
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			<td>Fisherbrand Tubes 50 ml</td>
			<td>Fisher</td>
			<td></td>
			<td>Or equivalent equipment&#160;</td>
		</tr>
		<tr>
			<td>Fisherbrand Tubes 15 ml</td>
			<td>Fisher</td>
			<td></td>
			<td>Or equivalent equipment&#160;</td>
		</tr>
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			<td>Sucrose</td>
			<td>Fisher chemical</td>
			<td>S5-3</td>
			<td></td>
		</tr>
		<tr>
			<td>Transfer pipette fine tip</td>
			<td>Samco Scientific</td>
			<td>232</td>
			<td>Or equivalent equipment&#160;</td>
		</tr>
		<tr>
			<td>Flow Cytometery Staining Buffer Solution</td>
			<td>EBioscience</td>
			<td>00-4222-26</td>
			<td>Or equivalent equipment&#160;</td>
		</tr>
		<tr>
			<td>1X RBC Lysis Buffer</td>
			<td>EBioscience</td>
			<td>00-4333-57</td>
			<td>Or equivalent equipment&#160;</td>
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reliable and high efficiency extraction of kidney immune cells

Immune system activation occurs in multiple kidney diseases and pathophysiological processes. The immune system consists of both adaptive and innate components and multiple cell types. Sometimes, the cell type of interest is present in very low numbers among the large numbers of total cells isolated from the kidney. Hence, reliable and efficient isolation of kidney mononuclear cell populations is important in order to study the immunological problems associated with kidney diseases. Traditionally, tissue isolation of kidney mononuclear cells have been performed via enzymatic digestions using different varieties and strengths of collagenases/DNAses yielding varying numbers of viable immune cells. Recently, with the development of the mechanical tissue disruptors for single cell isolation, the collagenase digestion step is avoided and replaced by a simple mechanical disruption of the kidneys after extraction from the mouse. Herein, we demonstrate a simple yet efficient method for the isolation of kidney mononuclear cells for every day immune cell extractions. We further demonstrate an example of subset analysis of immune cells in the kidney. Importantly, this technique can be adapted to other soft and non-fibrous tissues such as the liver and brain.

The number of panels that can be run depends on the number of immune cells that can be reliably extracted out of the kidneys. Herein, we demonstrate the ability to run 2 panels, one for T-lymphocytes and one for macrophages/dendritic cells. On the T-lymphocyte panel, we first look at the forward scatter (FSC) and side scatter (SSC) pattern and delineate the population of interest as shown in Figure 1 (top left dot plot). Next, a viability marker, in this case a fixable vi...

Watch this Scientific Journal Video about Reliable and High Efficiency Extraction of Kidney Immune Cells at JoVE.com

Reliable and High Efficiency Extraction of Kidney Immune Cells

Techniques that are reliable and efficient for the isolation of kidney immune cells are needed for downstream applications. This requires surface antibody labeling of a small number of kidney immune cells. Herein, we describe a concise method for isolation of kidney immune cells that seemingly achieves this goal.

Immune system activation occurs in multiple kidney diseases and pathophysiological processes.  The immune system consists of both adaptive and innate ...

The overall goal of this kidney immune cell isolation protocol is to extract viable single cell suspensions of kidney immune cells in adequate numbers for downstream analysis using multicolor flow cytometry. The main advantage of this technique, compared to collagenase digestion, is the ability to reliably and inexpensively isolate a large number of kidney immune cells for downstream experimental analysis. This method can help answer key questions in the kidney immunobiology field.For example, what subset of kidney immune cells regulate cytokine or chemokine secretion in a specific kidney disease. This method is demonstrated for the isolation of the immune cells from the kidney. However, it can be easily adapted to isolate the cells from other systems like liver or brain.Today, we'll be demonstrating a procedure for collecting kidney immune cells. And the procedure will be demonstrated by Alex Meuth, a research specialist from my lab. After confirming a lack of response to toe pinch, use 70%ethanol to clean the ventral abdomen of an anesthetized mouse.Then, use scissors to open the abdominal cavity, and reflect the abdominal organs to the left side of the animal. Using a one cc syringe equipped with a bent 25 gauge needle, collect the blood from the inferior vena cava into a 1.5 milliliter microcentrifuge tube containing 10 microliters of potassium EDTA. Next, make a small cut in the right atrium, and use a pair of forceps to gently grasp the heart.Then, insert a 21 to 25 gauge needle attached to a 50 cc syringe filled with 20 to 30 milliliters of ice-cold PBS into the left ventricle at its apex, and slowly perfuse the ventricle for one to two minutes. The heart will blanch after the first few milliliters of PBS. Liver blanching indicates that blood is being flushed through the liver via the venous return through the vena cava.When the perfusion is complete, use scissors and forceps to dissect the right kidney from the attached blood vessels, fat, and adrenal glands. Then, gently remove the kidney capsule with forceps, and weigh the kidney as experimentally appropriate. Next, transfer the kidney into a 50 milliliter conical tube containing one milliliter of flow cytometry buffer on ice.Label a five to 80 milliliter capacity homogenization bag with the appropriate sample identification information, and discard the inside strainer. Fill the bag with five milliliters of ice-cold flow cytometry staining buffer, and place the kidney in the bag. Fold the homogenization bag in half, such that one half has the kidney submerged in the buffer, and the other half is folded over it.Place the folded homogenization bag with the kidney facing the paddle close to the bottom edge, taking care that the lower end of the bag does not slide below the lower border of the paddles. Then, visually confirm that the kidneys are adequately homogenized and that no large chunks are visible. If the kidneys are not sufficiently mashed by the instrument, move the paddles closer to the wall of the homogenizer.Then, place one 100 micron cell strainer into an individual 50 milliliter conical tube per sample on ice, and completely filter the homogenates through the strainers. When all of the samples have been dissociated, centrifuge the tubes with the strainers to ensure that all of the tissues are completely filtered, and place the tubes back on ice. Next, add an equal volume of RBC lysis buffer to each sample, and pipette up and down several times to generate uniform cell suspensions.After five minutes, pellet the cells by centrifugation, and carefully discard the supernatant from each tube in one smooth motion, decanting the final drop of liquid that forms while each tube is still upside down. To isolate the kidney immune cells, add one milliliter of 72%density gradient reagent into one round-bottom polypropylene tube for each sample. Next, gently but vigorously triturate one milliliter of 0.25 molar sucrose into each pellet to obtain single cell suspensions, and add the cells to the density gradient solutions.Then, gently layer one milliliter of 72%density gradient reagent under each cell suspension to form distinct heavy layers. Confirm that the kidney cells are uniformly suspended for the 36%percoll gradient in each tube. Then, carefully layer the 72%percoll underneath the 36%percoll to form distinct 36 and 72 layers.Carefully place the tubes in the centrifuge for density gradient separation. Then, use a polypropylene Pasteur pipette to gently but thoroughly transfer all but about the last three millimeters of the upper junk layers into individual empty round-bottom centrifuge tubes. Now, use a fresh Pasteur pipette to gently transfer the buffy coats into new round-bottom centrifuge tubes until three to five millimeters below the buffy coat has been removed to ensure that most of the cells from each sample have been collected.Then, mix one to two milliliters of flow cytometry staining buffer into the buffy coats, and centrifuge the cells. Resuspend the pellets in 500 microliters of flow cytometry staining buffer for counting, and evenly split the samples into a dark, U-bottomed, 96-well plate. Incubate the samples in blocking antibody for 15 minutes at four degrees Celsius.Then, prepare an antibody cocktail for each immune cell type to be tested. For example, lymphocytes, macrophages, and dendritic cells, and incubate the cells in the appropriate antibody cocktail for 30 minutes at four degrees Celsius. After selecting the population of interest by forward and side scatter, exclude the non-viable cells.Two to 18%of the total kidney immune cells typically express CD45. To isolate the effector and cytotoxic T cells, for example, these bone marrow-derived hematopoietic cells can then be gated on CD4 and CD8 respectively. Further characterization of the CD4-positive cells reveals an approximately eight to 14%population of FoxP3-positive regulatory T cells, which can be subdivided into CD44 and CD127 expressing populations.To evaluate the myeloid cell panel, the CD45-positive cells can be gated by their Ly6G expression to first exclude the neutrophils. CD11b and F4/80 can then be used to further subdivide the Ly6C positive cells into the infiltrating macrophage and dendritic cell populations. Once mastered, this technique can be completed in one to two hours.Following this procedure, downstream experiments, such as the isolation of CD11b or CD4-positive cells can be performed to answer questions on cytokine secretion by this specific subset of cells. After watching this video, you should have a good understanding of how to perfuse the kidneys, generate a viable kidney cell suspension, isolate kidney immune cells by gradient density centrifugation, and label the kidney cells for flow cytometric analysis.

reliable-and-high-efficiency-extraction-of-kidney-immune-cells

Research

JoVE Journal

Immunology and Infection

Measuring Calpain Activity in Fixed and Living Cells by Flow Cytometry

Calpains are ubiquitous intracellular, calcium-sensitive, neutral cysteine proteases 1. Calpains play crucial roles in many physiological processes, including signaling, cytoskeletal remodeling, regulation of gene expression, apoptosis and cell cycle progression 1. Calpains have been implicated in many pathologies including muscular dystrophies, cancer, diabetes, Alzheimer's disease and multiple sclerosis 1. Calpain regulation is complex and incompletely understood. mRNA and protein levels correlate poorly with activity, limiting the use of gene or protein expression techniques to measure calpain activity. This video protocol details a flow cytometric assay developed in our laboratory for measuring calpain activity in fixed and living cells. This method uses the fluorescent substrate BOC-LM-CMAC, which is cleaved specifically by calpain, to measure calpain activity. 2 In this video, calpain activity in fixed and living murine 32Dkit leukemia cells, alone or as part of a splenocyte population is measured using an LSRII (BD Bioscience). 32Dkit cells are shown to have elevated activity compared to normal splenocytes.

This article will detail the protocol for measuring calpain activity in fixed and living cells using flow cytometry.

Calpains are ubiquitous intracellular, calcium-sensitive, neutral cysteine proteases 1. Calpains play crucial roles in many physiological processes, ...

Seven Steps to Stellate Cells

Hepatic stellate cells are liver-resident cells of star-like morphology and are located in the space of Disse between liver sinusoidal endothelial cells and hepatocytes1,2. Stellate cells are derived from bone marrow precursors and store up to 80% of the total body vitamin A1, 2. Upon activation, stellate cells differentiate into myofibroblasts to produce extracellular matrix, thus contributing to liver fibrosis3. Based on their ability to contract, myofibroblastic stellate cells can regulate the vascular tone associated with portal hypertension4. Recently, we demonstrated that hepatic stellate cells are potent antigen presenting cells and can activate NKT cells as well as conventional T lymphocytes5. 

 Here we present a method for the efficient preparation of hepatic stellate cells from mouse liver. Due to their perisinusoidal localization, the isolation of hepatic stellate cells is a multi-step process. In order to render stellate cells accessible to isolation from the space of Disse, mouse livers are perfused in situ with the digestive enzymes Pronase E and Collagenase P. Following perfusion, the liver tissue is subjected to additional enzymatic treatment with Pronase E and Collagenase P in vitro. Subsequently, the method takes advantage of the massive amount of vitamin A-storing lipid droplets in hepatic stellate cells. This feature allows the separation of stellate cells from other hepatic cell types by centrifugation on an 8% Nycodenz gradient. The protocol described here yields a highly pure and homogenous population of stellate cells. Purity of preparations can be assessed by staining for the marker molecule glial fibrillary acidic protein (GFAP), prior to analysis by fluorescence microscopy or flow cytometry. Further, light microscopy reveals the unique appearance of star-shaped hepatic stellate cells that harbor high amounts of lipid droplets. 


 Taken together, we present a detailed protocol for the efficient isolation of hepatic stellate cells, including representative images of their morphological appearance and GFAP expression that help to define the stellate cell entity.

Here we describe a method for the isolation of hepatic stellate cells from mouse liver. For stellate cell purification, mouse livers are digested in situ and in vitro by pronase-collagenase treatment prior to density gradient centrifugation. This technique yields highly pure hepatic stellate cells.

Hepatic stellate cells are liver-resident  cells of star-like morphology and are located in the space of Disse between  liver sinusoidal endothelial cells ...

Flow Cytometry Analysis of Immune Cells Within Murine Aortas

Atherosclerosis is a chronic inflammatory process of medium and large size vessels that is characterized by the formation of plaques consisting of foam cells, immune cells, vascular endothelial and smooth muscle cells, platelets, extracellular matrix, and a lipid-rich core with extensive necrosis and fibrosis of surrounding tissues.1 The innate and adaptive arms of the immune response are involved in the initiation, development and persistence of atherosclerosis.2, 3 There is a significant body of evidence that different subsets of the immune cells, such as macrophages, dendritic cells, T and B lymphocytes, are present within the aortas of healthy and atherosclerosis-prone mice4. Additionally, immune cells are found in the surrounding aortic adventitia which suggests an important role of this tissue in atherogenesis.2
For some time, the quantitative detection of different types of immune cells, their activation status, and the cellular composition within the aortic wall was limited by RT-PCR and immunohistochemical methods for the study of atherosclerosis. Few attempts were made to perform flow cytometry using human aortas, and a number of problems, such as a high autofluorescence, have been reported5,6. Human atherosclerotic plaques were digested with collagenase 1, and free cells were collected and stained for CD14+/CD11c+ to highlight macrophage-derived foam cells. In this study, a "mock" channel was used to avoid false-positive staining.6 Necrotic materials accumulating during the digestion process give rise in a large amount of debris that generates a high autofluorescence in aortic samples. To resolve this problem, a panel of negative and positive controls has been proposed, but only double staining could be applied in these samples. We have developed a new flow cytometry-based method7 to analyze the immune cell composition and characterize the activation, proliferation, differentiation of immune cells in healthy and atherosclerosis-prone aorta. This method allows the investigation of the immune cell composition of the aortic wall and opens possibilities to use a broad spectrum of immunological methods for investigations of immune aspects of this disease.

This paper presents a flow cytometry-based method to investigate the immune composition of aortas. The paper also illustrates an additional technique that allows examining surrounding adventitia and vessel wall separately. This method opens possibilities to perform phenotypical analyses of aortic leukocytes and apply several immunological assays for atherosclerosis studies.

Atherosclerosis is a chronic inflammatory process of medium and large size vessels that is characterized by the formation of plaques consisting of foam ...

Isolation of Functional Cardiac Immune Cells

Cardiac immune cells are gaining interest for the roles they play in the pathological remodeling in many cardiac diseases.1-5 These immune cells, which include mast cells, T-cells and macrophages; store and release a variety of biologically active mediators including cytokines and proteases such as tryptase.6-8 These mediators have been shown to be key players in extracellular matrix metabolism by activating matrix metalloproteinases or causing collagen accumulation by modulating the cardiac fibroblasts' function.9-11 However, available techniques for isolating cardiac immune cells have been problematic because they use bacterial collagenase to digest the myocardial tissue. This technique causes activation of the immune cells and thus a loss of function. For example, cardiac mast cells become significantly less responsive to compounds that cause degranulation.12 Therefore, we developed a technique that allows for the isolation of functional cardiac immune cells which would lead to a better understanding of the role of these cells in cardiac disease.13, 14
This method requires a familiarity with the anatomical location of the rat's xiphoid process, axilla and falciform ligament, and pericardium of the heart. These landmarks are important to increase success of the procedure and to ensure a higher yield of cardiac immune cells. These isolated cardiac immune cells can then be used for characterization of functionality, phenotype, maturity, and co-culture experiments with other cardiac cells to gain a better understanding of their interactions.

This method for isolating functional immune cells from the heart provides an alternative to the conventional methods of collagenase digestion, which causes unwanted immune cell activation, resulting in a decreased responsiveness of these cells. Our method of isolation yields functional cardiac immune cells by avoiding problems associated with enzymatic digestion.

Cardiac immune cells are gaining interest for the roles they play in the pathological remodeling in many cardiac diseases.1-5  These immune cells, which ...

Intravital Imaging of the Mouse Thymus using 2-Photon Microscopy

Two-photon Microscopy (TPM) provides image acquisition in deep areas inside tissues and organs. In combination with the development of new stereotactic tools and surgical procedures, TPM becomes a powerful technique to identify "niches" inside organs and to document cellular "behaviors" in live animals. While intravital imaging provides information that best resembles the real cellular behavior inside the organ, it is both more laborious and technically demanding in terms of required equipment/procedures than alternative ex vivo imaging acquisition. Thus, we describe a surgical procedure and novel "stereotactic" organ holder that allows us to follow the movements of Foxp3+ cells within the thymus.
Foxp3 is the master regulator for the generation of regulatory T cells (Tregs). Moreover, these cells can be classified according to their origin: ie. thymus-differentiated Tregs are called "naturally-occurring Tregs" (nTregs), as opposed to peripherally-converted Tregs (pTregs). Although significant amount of research has been reported in the literature concerning the phenotype and physiology of these T cells, very little is known about their in vivo interactions with other cells. This deficiency may be due to the absence of techniques that would permit such observations. The protocol described in this paper provides a remedy for this situation.
Our protocol consists of using nude mice that lack an endogenous thymus since they have a punctual mutation in the DNA sequence that compromises the differentiation of some epithelial cells, including thymic epithelial cells. Nude mice were gamma-irradiated and reconstituted with bone marrows (BM) from Foxp3-KIgfp/gfp mice. After BM recovery (6 weeks), each animal received embryonic thymus transplantation inside the kidney capsule. After thymus acceptance (6 weeks), the animals were anesthetized; the kidney containing the transplanted thymus was exposed, fixed in our organ holder, and kept under physiological conditions for in vivo imaging by TPM. We have been using this approach to study the influence of drugs in the generation of regulatory T cells.

We have developed novel laboratory tools and protocols for intravital imaging acquisition of the thymus. Our technique should help in the identification of &#x201C;niches&#x201D; within the thymus where T cell development occurs.

Two-photon Microscopy (TPM) provides image acquisition in deep areas inside tissues and organs. In combination with the development of new stereotactic ...

Isolation of Adipose Tissue Immune Cells

The discovery of increased macrophage infiltration in the adipose tissue (AT) of obese rodents and humans has led to an intensification of interest in immune cell contribution to local and systemic insulin resistance. Isolation and quantification of different immune cell populations in lean and obese AT is now a commonly utilized technique in immunometabolism laboratories; yet extreme care must be taken both in stromal vascular cell isolation and in the flow cytometry analysis so that the data obtained is reliable and interpretable. In this video we demonstrate how to mince, digest, and isolate the immune cell-enriched stromal vascular fraction. Subsequently, we show how to antibody label macrophages and T lymphocytes and how to properly gate on them in flow cytometry experiments. Representative flow cytometry plots from low fat-fed lean and high fat-fed obese mice are provided. A critical element of this analysis is the use of antibodies that do not fluoresce in channels where AT macrophages are naturally autofluorescent, as well as the use of proper compensation controls.

Adipose tissue (AT) is a site of intense immune cell activation and interaction. Almost all cells of the immune system are present in AT and their ratios are altered by obesity. Proper isolation, quantification, and characterization of AT immune cell populations are critical for understanding their role in immunometabolic disease.

The discovery of increased macrophage infiltration in  the adipose tissue (AT) of obese rodents and humans has led to an  intensification of interest in ...

Isolation of Double Negative &#945;&#946; T Cells from the Kidney

There is currently no standard protocol for the isolation of DN T cells from the non-lymphoid tissues despite their increasingly reported involvement in various immune responses. DN T cells are a unique immune cell type that has been implicated in regulating immune and autoimmune responses and tolerance to allotransplants1-6. DN T cells are, however, rare in peripheral blood and secondary lymphoid organs (spleen and lymph nodes), but are major residents of the normal kidney. Very little is known about their pathophysiologic function7 due to their paucity in the periphery. We recently described a comprehensive phenotypic and functional analysis of this population in the kidney8 in steady state and during ischemia reperfusion injury. Analysis of DN T cell function will be greatly enhanced by developing a protocol for their isolation from the kidney.
Here, we describe a novel protocol that allows isolation of highly pure ab CD4+ CD8+ T cells and DN T cells from the murine kidney. Briefly, we digest kidney tissue using collagenase and isolate kidney mononuclear cells (KMNC) by density gradient. This is followed by two steps to enrich hematopoietic T cells from 3% to 70% from KMNC. The first step consists of a positive selection of hematopoietic cells using a CD45+ isolation kit. In the second step, DN T cells are negatively isolated by removal of non-desired cells using CD4, CD8, and MHC class II monoclonal antibodies and CD1d &#945;-galcer tetramer. This strategy leads to a population of more than 90% pure DN T cells. Surface staining with the above mentioned antibodies followed by FACs analysis is used to confirm purity.

Isolation of Double Negative &amp;#945;&amp;#946; T Cells from the Kidney

DNabT cells are rare among peripheral T cells; however, they are abundant in certain non-lymphoid tissues. Difficulty of isolating DN T cells from non-lymphoid tissue hinders their functional analysis despite increasing recognized pathophysiologic significance. We describe a novel protocol for isolation of highly purified DN T cells from murine kidney.

There is currently no standard protocol for the isolation of DN T cells from the non-lymphoid tissues despite their increasingly reported involvement in ...

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 ...

Light-sheet Microscopy for Three-dimensional Visualization of Human Immune Cells

In vivo, activation, proliferation, and function of immune cells all occur in a three-dimensional (3D) environment, for instance in lymph nodes or tissues. Up to date, most in vitro systems rely on two-dimensional (2D) surfaces, such as cell-culture plates or coverslips. To optimally mimic physiological conditions in vitro, we utilize a simple 3D collagen matrix. Collagen is one of the major components of extracellular matrix (ECM) and has been widely used to constitute 3D matrices. For 3D imaging, the recently developed light-sheet microscopy technology (also referred to as single plane illumination microscopy) is featured with high acquisition speed, large penetration depth, low bleaching, and photocytotoxicity. Furthermore, light-sheet microscopy is particularly advantageous for long-term measurement. Here we describe an optimized protocol how to set up and handle human immune cells, e.g. primary human cytotoxic T lymphocytes (CTL) and natural killer (NK) cells in the 3D collagen matrix for usage with the light-sheet microscopy for live cell imaging and fixed samples. The procedure for image acquisition and analysis of cell migration are presented. A particular focus is given to highlight critical steps and factors for sample preparation and data analysis. This protocol can be employed for other types of suspension cells in a 3D collagen matrix and is not limited to immune cells.

Here, we present a protocol to visualize immune cells embedded in a three-dimensional (3D) collagen matrix using light-sheet microscopy. This protocol also elaborates how to track cell migration in 3D. This protocol can be employed for other types of suspension cells in the 3D matrix.

In vivo, activation, proliferation, and function of immune cells all occur in a three-dimensional (3D) environment, for instance in lymph nodes or ...

Isolation and Identification of Extravascular Immune Cells of the Heart

The immune system is an essential component of a healthy heart. The myocardium is home to a rich population of different immune cell subsets with functional compartmentalization both during steady state and during different forms of inflammation. Until recently, the study of immune cells in the heart required the use of microscopy or poorly developed digestion protocols, which provided enough sensitivity during severe inflammation but were unable to confidently identify small &#8212; but key &#8212; populations of cells during steady state. Here, we discuss a simple method combining enzymatic (collagenase, hyaluronidase and DNAse) and mechanical digestion of murine hearts preceded by intravascular administration of fluorescently-labelled antibodies to differentiate small but unavoidable intravascular cell contaminants. This method generates a suspension of isolated viable cells that can be analyzed by flow cytometry for identification, phenotyping and quantification, or further purified with fluorescence-activated cell sorting or magnetic bead separation for transcriptional analysis or in vitro studies. We include an example of a step-by-step flow cytometric analysis to differentiate the key macrophage and dendritic cell populations of the heart. For a medium sized experiment (10 hearts) the completion of the procedure requires 2&#8211;3 h.

This protocol presents a simple and efficient method to isolate, identify and quantify immune cells residing in the myocardium of mice during steady state or inflammation. The protocol combines enzymatic and mechanical digestion for the generation of a single cell suspension that can be further analyzed by flow cytometry.