Authors were supported by the German Cancer Aid (Max Eder Nachwuchsgruppe, Deutsche Krebshilfe; EU), the LOEWE Center for Cell and Gene Therapy Frankfurt (EU, ST) funded by the Hessian Ministry of Higher Education, Research and the Arts, Germany (III L 4- 518/17.004) and by the "Alfred- und Angelika Gutermuth-Stiftung", Frankfurt, Germany (EU). BJ was funded by a Mildred Scheel postdoctoral scholarship from the Dr. Mildred Scheel Foundation for Cancer Research. ST was founded by a GO-IN postdoctoral fellowship (PCOFUND-GA-2011-291776). The authors thank Becton Dickinson (BD) for providing the FACSCanto II and Canto10c Flow Cytometry Analyzers used in this study.

This study was carried out in accordance with the recommendations of the local ethics committee of the University of Frankfurt.
1. Culturing of K562 Cells
<ol>
	<li>Culture K562 cells in R10 media (RPMI1640 with glutamine medium, 1% penicillin/streptomycin, 10% fetal calf serum) at a density of 0.5-1 x 106 cells per ml in a cell culture flask at 37 &#176;C and 5% CO2.</li>
	<li>Harvest K562 Cells 24 hr Before the Start of a New Experiment.
	<ol>
		<li>Remove the cell culture flask containing the K562 cells from the incubator. Re-suspend the K562 cells within the culture media by gently pipetting up and down.</li>
		<li>Transfer the culture media containing the K562 cells into a 15 or 50 ml tube and pellet the cells at 400 x g for 8 min. Discard the supernatant and re-suspend the cells in 5 ml R10 media and mix well.</li>
		<li>Transfer 20 &#181;l of the cell solution into a well of a 96-U-well plate. Add 20 &#181;l trypan blue and mix well by pipetting up and down for at least 5 times. Pipette 10 &#181;l of the solution into a cell counting chamber and count the cells.</li>
		<li>Pellet the cells at 400 x g for 8 min. Re-suspend the cells in R10 media and adjust the K562 cell concentration to 0.5-1 x 106 cells per ml.</li>
		<li>Incubate the K562 cells in a cell culture flask at 37 &#176;C and 5% CO2 until use.</li>
	</ol>
	</li>
</ol>
2. Isolation of NK Cells
<ol>
	<li>According to the approval and guidelines of the local ethics committee, obtain written informed consent of the healthy donor or patient before the collection of 6-10 ml of either EDTA or heparinized peripheral blood.</li>
	<li>Store reagents for the NK cell isolation at 4 &#176;C until the start of the experiment and then use them at room temperature (RT) under sterile conditions. Isolate NK cells from peripheral blood using magnetic microbeads and a specific magnet for cell isolation according to the manufacturer&#39;s instructions.
	<ol>
		<li>Reconstitute one vial of the lyophilized NK cell negative isolation antibody cocktail by pipetting 7.5 ml of the provided buffer A (included within the NK cell isolation kit) into the vial. Mix gently by pipetting up and down 3-4 times. 
		NOTE: Make sure, that the suspension is homogenous before each use.</li>
		<li>Prepare the final cocktail solution by mixing appropriate volumes of the reconstituted pellet from step 2.2.1 and buffer B (included within the NK cell isolation kit). To determine these volumes, define the volume of the whole blood sample in ml as volume = 1.0. Use 0.25 volumes of the reconstituted pellet (from step 2.2.1) and 0.25 volumes of buffer B to process 1 volume of whole blood.</li>
		<li>Transfer the mixture into an adequate tube containing the whole blood sample. Do not pipette up and down to avoid the loss of blood within the pipette. Instead, close the tube and move it carefully up and down until the suspension is homogenous. Do not vortex.</li>
		<li>Further homogenize the sample using a tube rotator for 5 min at RT.</li>
		<li>Under sterile conditions, remove the cap and place the tube into the magnetic separator for 15 min as recommended by the manufacturer. Make sure that the tube labels face towards the backside of the magnet to allow undisturbed visibility of the separation line. Do not move the magnet during separation, as this procedure would be disturbed.</li>
		<li>Carefully transfer the supernatant into a new 15 ml tube and fill up with complete media (CM; hematopoietic cell media, 1% penicillin/streptomycin, 5% human sera). Pellet the cells at 400 x g for 8 min.
		<ol>
			<li>Optional: If the pellet is red, re-suspend the cells in 1ml of erythrocyte lysis buffer (e.g., 1 ml of ammonium-chloride-potassium (ACK) lysing buffer: 155 mM NH4Cl; 0.1 mM EDTA; 10 mM KHCO3 in 1 L distilled water (DW)) and incubate for 8 min at RT. Alternatively, use an erythrocyte depletion kit. 
			NOTE: Keep in mind, that the use of ACK buffer might negatively impact NK cell functions14.</li>
			<li>Rapidly dilute the ACK buffer by adding at least 1 ml of CM to stop the lysis and centrifuge at 400 x g for 8 min to pellet the cells.</li>
		</ol>
		</li>
		<li>Re-suspend the cell pellet in 1 ml CM and proceed with the counting. Transfer 20 &#181;l of the NK cell solution onto a 96-U-well plate. Add 20 &#181;l of methylene blue to each well and mix well by pipetting up and down for at least 5 times. Pipette 10 &#181;l of the solution into a cell counting chamber and count cells. Alternatively, use 30 &#181;l of undiluted cell suspension for counting with a commercially available cell counter.</li>
		<li>Adjust the cells to a concentration of at least 2 x 104 NK cells per 100 &#181;l CM.</li>
		<li>Perform a surface antibody staining of the isolated NK cell population to check the purity using a flow cytometer.
		<ol>
			<li>Prepare a master mix solution by mixing the volumes of the indicated antibodies as per Table 1.</li>
			<li>Re-suspend the cells in 88.5 &#181;l washing buffer (WB; 0.5% bovine serum albumin (BSA), 0.1% NaN3 in PBS) and add 11.5 &#181;l of the master mix solution. Incubate the cells for 20 min at 4 &#176;C in the dark. 
			Caution: NaN3 is toxic and mutagen. Handle it accordingly to the corresponding Material Safety Data Sheet (MSDS).</li>
			<li>Add 1 ml of WB and pellet the cells at 400 x g for 4 min.</li>
			<li>Re-suspend the cells in 300 &#181;l staining buffer plus DAPI. Acquire the cells using a flow cytometer. 
			NOTE: Proceed further with the experiment only if the NK cell purity is at least 80% of all alive lymphocytes.</li>
		</ol>
		</li>
	</ol>
	</li>
</ol>
3. Harvesting of the K562 Cells for NK Cell Stimulation
<ol>
	<li>Remove the cell culture flask containing the K562 cells (from step 1.2) from the incubator. Re-suspend the K562 cells within the culture media by gently pipetting up and down.</li>
	<li>Transfer the whole culture media into a 15 or 50 ml tube and pellet the cells at 400 x g for 8 min. Discard the supernatant and re-suspend the cells in 5 ml phosphate-buffered saline (PBS) and mix well.</li>
	<li>Transfer 20 &#181;l of the cell solution into a well of a 96-U-well plate. Add 20 &#181;l trypan blue and mix well by pipetting up and down for at least 5 times. Pipette 10 &#181;l of the solution into a cell counting chamber and count the cells. Alternatively use 30 &#181;l of undiluted cell suspension to count with a commercially available cell counter.</li>
	<li>Pellet the cells at 400 x g for 8 min. Re-suspend cells in CM at a concentration of at least 2 x 104 K562 cells per 100 &#181;l media. 
	NOTE: Use the same K562 and NK cell concentrations in order to incubate both at an effector:target (E:T) ratio of 1:1 later on.</li>
</ol>
4. Stimulation of NK Cells with the Tumor Cell Line K562 and Cytokines
<ol>
	<li>Gently mix the cells by pipetting them up and down for at least 5 times. Distribute 100 &#181;l/well of the NK cell solution into the required wells of a 96-V-well plate.
	<ol>
		<li>Use at least two wells for each donor, one with and one without a stimulus (e.g., K562 tumor cells and cytokines). Whenever possible, perform the experiment at least in duplicate and add a positive control (e.g., phorbol 12-myristate 13-acetate (PMA) and ionomycin; final concentration: 50 nM PMA, 1 &#181;M ionomycin per well). Prepare updated flow cytometry compensations for the date of the experiment. 
		NOTE: Titrate the antibodies prior use (see discussion).</li>
	</ol>
	</li>
	<li>Switch off the light and add the anti-CD107a antibody (2 &#181;l, final concentration: 1:100) to each well with NK cells on the 96-V-well plate.</li>
	<li>Gently mix the K562 cells by pipetting them up and down for at least 5 times.
	<ol>
		<li>From the wells containing the NK cell/anti-CD107a antibody solution, identify the ones planned for stimulation with K562 cells. Add 100 &#181;l/well of the K562 cell solution into these wells. Mix carefully by pipetting up and down for at least 5 times.</li>
		<li>Add interleukin-2 (IL-2; final concentration 100 U/ml) and interleukin-15 (IL-15; final concentration 10 ng/ml) to the wells containing K562 cells and the NK cell/anti-CD107a antibody solution.
		<ol>
			<li>Optional: Test the impact of either K562 cells or cytokines alone on the distributed NK cells to decipher tumor-induced versus cytokine-induced NK cell functions.</li>
		</ol>
		</li>
		<li>Identify the wells on the 96-V-well plate planned as negative controls without stimulus. Add 100 &#181;l/well CM to these wells containing only the NK cell/anti-CD107a antibody solution. Mix carefully by pipetting up and down for at least 5 times.
		<ol>
			<li>Optional: For a positive control, add 100 &#181;l CM containing PMA and ionomycin (final concentration: 50 nM PMA, 1 &#181;M ionomycin per well) to a well with the NK cell/anti-CD107a antibody solution.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Incubate the Cells for 3 hr in the Dark at 37 &#176;C and 5% CO2.</li>
	<li>Prepare a protein transport inhibitor solution (e.g., brefeldin A and/or monensin) in CM. After 1 hr of incubation, add the solution to each well of the 96-V-well plate with the light switched off (final concentration: 0.5-1&#181;M brefeldin A and 2-3 &#181;M monensin). Mix carefully by pipetting up and down for at least 5 times. Continue the incubation for the remaining 2 hr.</li>
</ol>
5. Surface and Intracellular Staining
<ol>
	<li>After the 3 hr incubation period, mix the cells within the wells of the 96-V-well plate carefully by pipetting up and down for at least 5 times and transfer them into flow cytometry tubes. Add 1 ml/tube of WB. Pellet cells at 400 x g for 4 min.
	<ol>
		<li>Optional: Before centrifugation rinse the wells with 100 &#181;l/well PBS, in order to optimize the cell recovery, by pipetting up and down for at least 5 times before transferring the cells into the respective FACS tube.</li>
	</ol>
	</li>
	<li>Discard the Supernatant and Continue with the Surface Staining.</li>
	<li>Include an amine-reactive fluorescent dye that is non-permeant to live cells with an emission maximum of 423 nm as a fixable dead cell marker (DCM). Perform the staining before (see below) or in parallel with the antibody surface staining depending on the type of the DCM used.
	<ol>
		<li>Re-suspend cells in 99 &#181;l/tube PBS and add 1 &#181;l/tube of the fixable DCM (final concentration: 1:100). Mix cells well using a vortex and incubate them for 15 min at RT in the dark.</li>
		<li>Prepare a master mix solution by mixing together the &#34;surface&#34; antibodies listed in Table 2 (see staining step column highlighted in blue). Use the indicated volumes/tube and multiply them with the number of flow cytometry tubes to be stained.</li>
		<li>After incubation take the flow cytometry tubes with the cells and add 1 ml/tube of WB. Pellet the cells at 400 x g for 4 min.</li>
		<li>Discard the supernatant, re-suspend the cells in 84 &#181;l/tube of WB and add 16 &#181;l/tube of the master mix solution. Mix cells well using a vortex. Incubate cells for 20 min at 4 &#176;C in the dark.</li>
		<li>After 20 min add 1 ml/tube WB and pellet cells at 400 x g for 4 min.</li>
	</ol>
	</li>
	<li>Discard the supernatant and re-suspend the cells in 100 &#181;l/tube of a cold fixation solution (e.g., 2% (final) paraformaldehyde or formaldehyde). Mix cells well using a vortex. Incubate cells for 10 min at 4 &#176;C in the dark.
	<ol>
		<li>Stain the cells for intracellular cytokines/chemokines after this step or store them overnight at 4 &#176;C in WB. 
		NOTE: After overnight incubation, a lower cell recovery may occur. 
		Caution: Paraformaldehyde and formaldehyde are potential carcinogens. Handle them accordingly to the respective Material Safety Data Sheet (MSDS).</li>
	</ol>
	</li>
	<li>Wash cells in 1 ml/tube WB at 400 x g for 4 min and proceed with the permeabilization step.</li>
	<li>Prepare a permeabilization buffer (PB) (e.g., 0.2% saponin, 1% BSA solution in PBS).</li>
	<li>Wash the cells twice in 1 ml/tube of PB at 400 x g for 4 min. Continue with the intracellular staining. 
	Caution: Saponin is potentially irritating. Handle it accordingly to the corresponding Material Safety Data Sheet (MSDS).</li>
	<li>Prepare a master mix solution using the indicated &#34;intracellular&#34; antibody volumes in Table 2 (highlighted in green). Multiply these volumes with the number of tubes to be stained.
	<ol>
		<li>Re-suspend the cells in 90 &#181;l/tube PB and apply 10 &#181;l/tube of the antibody master mix solution. Mix well using a vortex and incubate the cells for 30 min at 4 &#176;C in the dark.</li>
	</ol>
	</li>
	<li>Wash Cells Twice in 1 ml/tube of PB at 400 x g for 4 min.</li>
	<li>Discard the supernatant and re-suspend the cells in 400 &#181;l/tube PB. Mix cells well using a vortex. Place cells on ice in the dark until measurement.</li>
</ol>
6. Flow Cytometry Compensation and Acquisition
<ol>
	<li>Select the channels for the different fluorochromes (see Table 2) within the flow cytometry acquisition software in the parameter setup folder. Additionally, choose the channels for FSC-A and -H as well as for SSC-A and -H.</li>
	<li>Load a compensation matrix created for the chosen parameters into the acquisition file.
	<ol>
		<li>Create a compensation matrix using isolated NK cells from step 2.2.8 by performing a single color stain for each used fluorochrome (see Table 2). Use the surface staining protocol described in steps 5.1-5.4. Include an unstained control (without any antibodies) as well as isotype controls and/or fluorescence minus one controls (FMO). 
		NOTE: As an alternative to cell-based compensation, use IgG-binding beads as compensation controls.</li>
		<li>Place each tube for single stain samples and the sample without antibodies into the sample injection port (SIP). Click on the &#34;record&#34; button in the flow cytometry acquisition software and acquire a cell number of at least 5 x 103 NK cells per sample.</li>
		<li>Use the compensation calculation application of the cytometry acquisition software to create a compensation matrix.</li>
	</ol>
	</li>
	<li>Create Dot Plots for Identifying the NK Cell Population.
	<ol>
		<li>Identify single cells using FSC-A/FSC-H and SSC-A/SSC-H dot plots. Click on the &#34;polygon gate&#34; button. Draw a gate around cells, which have a linear distribution pattern in both dot plots. Double-click on the gates to open a new dot plot.</li>
		<li>Choose a FSC-A/SSC-A dot plot to identify the lymphocyte/NK cell population (see Figure 1). Draw a polygon gate around it and double-click on the gate.</li>
	</ol>
	</li>
	<li>Place each sample tube of the NK cell stimulation assay into the SIP. Click on the &#34;record&#34; button and acquire a cell number of at least 5 x 103 NK cells per sample.</li>
</ol>
7. Analysis and Statistics
<ol>
	<li>Open the flow cytometry analysis software program. Click on the loading sample button to open the unstimulated control sample.</li>
	<li>Create a Gating System for the Different NK Cell Subpopulations (see Figure 1).
	<ol>
		<li>Click on the dot plot button to create a FSC-A/SSC-A plot. Click on the rectangle gate button and draw a rectangle gate over all events with a FSC-A value &#62;5 x 104 to exclude debris. Open the gate by double-clicking on the gate.</li>
		<li>Choose again the FSC-A/SSC-A parameters within the new dot plot and click on the polygon gate button. Draw a polygon gate around the lymphocyte population (see Figure 1). Open the gate.</li>
		<li>Select the SSC-A/SSC-H parameter for the new dot plot and draw a polygon gate around all single cells. Single cells demonstrate a linear distribution across the FSC-A/FSC-H and SSC-A/SSC-H parameters (see Figure 1). Open the gate by double-clicking on it.</li>
		<li>Repeat step 7.2.3 using the FSC-A/FSC-H parameters this time.</li>
		<li>Use the parameter CD45 and Dump channel (CD3; CD14; CD19; DCM) to exclude dead cells. Draw a rectangle gate around all CD45 positive and Dump channel negative cells. Open the gate by double-clicking on the gate.</li>
		<li>Identify the whole NK cell population by using the CD56 and Dump channel parameters. Create a rectangle gate around the CD56 positive and Dump channel negative cells. Open the gate by double-clicking on it.</li>
		<li>Draw a rectangle gate around all the three NK cell subsets within a CD56/CD16 dot plot. Identify the different subsets as CD56++CD16-, CD56++CD16+ and CD56+CD16++ NK cell subsets.</li>
	</ol>
	</li>
	<li>Analyze NK Cell Functions for Each Individual NK Cell Subset.
	<ol>
		<li>Click on one of the three NK cell subset gates to open it. Create three different dot plots for CD56/CD107a, CD56/IFN-&#947; and CD56/MIP-1&#946;.</li>
		<li>Draw a rectangle gate for CD56 positive cells, which are positive as well for CD107a, IFN-&#947; or MIP-1&#946; respectively (see Figure 1).</li>
		<li>Repeat step 7.3.1-7.3.2 for each remaining NK cell subset.</li>
	</ol>
	</li>
	<li>Repeat step 7.2 and 7.3 for all stimulated samples. Save all statistical values of each individual sample by clicking on the statistic-exporting button within the analysis software.</li>
	<li>Open the files containing the statistical values of the individual samples to analyze NK cell functions. Select the values for individual NK cell subsets (e.g., CD56++CD16- NK cells) by copying them into another file.
	<ol>
		<li>Subtract the percentage of CD107a positive NK cells, which have not been treated with a stimulus, from the percentage of CD107a positive NK cells, which have been treated with a stimulus. 
		NOTE: Use the result to demonstrate the degranulation capacity of this particular NK cell subset in response to the stimulus.</li>
		<li>Repeat step 7.5.1 for IFN-&#947; and MIP-1&#223;-positive NK cells to demonstrate the cytokine and chemokine production in response to the stimulus.</li>
		<li>Repeat step 7.5.1-7.5.2 for each remaining NK cell subset to evaluate their degranulation capacity and cytokine/chemokine production upon stimulation.</li>
	</ol>
	</li>
</ol>

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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=Serglycin+determines+secretory+granule+repertoire+and+regulates+NK+cell+and+CTL+cytotoxicity.">Serglycin determines secretory granule repertoire and regulates NK cell and CTL cytotoxicity.</a> FEBS J. 283 (5), 947-961 (2016).</li><li>Sch&#246;nberg, K., Hejazi, M., Uhrberg, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protocol+for+the+clonal+analysis+of+NK+cell+effector+functions+by+multi-parameter+flow+cytometry.">Protocol for the clonal analysis of NK cell effector functions by multi-parameter flow cytometry.</a> Methods Mol Biol. 903, 381-392 (2012).</li><li>Bj&#246;rkstr&#246;m, N. K., 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=Expression+patterns+of+NKG2A,+KIR,+and+CD57+define+a+process+of+CD56dim+NK-cell+differentiation+uncoupled+from+NK-cell+education.">Expression patterns of NKG2A, KIR, and CD57 define a process of CD56dim NK-cell differentiation uncoupled from NK-cell education.</a> Blood. 116 (19), 3853-3864 (2010).</li><li>Bryceson, Y. T., Ljunggren, H. G., Long, E. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimal+requirement+for+induction+of+natural+cytotoxicity+and+intersection+of+activation+signals+by+inhibitory+receptors.">Minimal requirement for induction of natural cytotoxicity and intersection of activation signals by inhibitory receptors.</a> Blood. 114 (13), 2657-2666 (2009).</li><li>Cooper, M. A., 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=Human+natural+killer+cells:+a+unique+innate+immunoregulatory+role+for+the+CD56(bright)+subset.">Human natural killer cells: a unique innate immunoregulatory role for the CD56(bright) subset.</a> Blood. 97 (10), 3146-3151 (2001).</li><li>Fauriat, C., Long, E. O., Ljunggren, H. G., Bryceson, Y. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+human+NK-cell+cytokine+and+chemokine+production+by+target+cell+recognition.">Regulation of human NK-cell cytokine and chemokine production by target cell recognition.</a> Blood. 115 (11), 2167-2176 (2010).</li><li>Postow, M. A., Callahan, M. K., Wolchok, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immune+Checkpoint+Blockade+in+Cancer+Therapy.">Immune Checkpoint Blockade in Cancer Therapy.</a> J Clin Oncol. 33 (17), 1974-1982 (2015).</li><li>Glienke, W., 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=Advantages+and+applications+of+CAR-expressing+natural+killer+cells.">Advantages and applications of CAR-expressing natural killer cells.</a> Front Pharmacol. 6, 21 (2015).</li><li>Curran, K. J., Brentjens, 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=Chimeric+antigen+receptor+T+cells+for+cancer+immunotherapy.">Chimeric antigen receptor T cells for cancer immunotherapy.</a> J Clin Oncol. 33 (15), 1703-1706 (2015).</li><li>Zappasodi, R., de Braud, F., Di Nicola, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lymphoma+Immunotherapy:+Current+Status.">Lymphoma Immunotherapy: Current Status.</a> Front. Immunol. 6, 448 (2015).</li><li>Laprevotte, 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=Endogenous+IL-8+acts+as+a+CD16+co-activator+for+natural+killer-mediated+anti-CD20+B+cell+depletion+in+chronic+lymphocytic+leukemia.">Endogenous IL-8 acts as a CD16 co-activator for natural killer-mediated anti-CD20 B cell depletion in chronic lymphocytic leukemia.</a> Leuk Res. 37 (4), 440-446 (2013).</li><li>Maloney, D. G., 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=IDEC-C2B8+(Rituximab)+anti-CD20+monoclonal+antibody+therapy+in+patients+with+relapsed+low-grade+non-Hodgkin's+lymphoma.">IDEC-C2B8 (Rituximab) anti-CD20 monoclonal antibody therapy in patients with relapsed low-grade non-Hodgkin's lymphoma.</a> Blood. 90 (6), 2188-2195 (1997).</li><li>Salles, G., 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=Phase+1+study+results+of+the+type+II+glycoengineered+humanized+anti-CD20+monoclonal+antibody+obinutuzumab+(GA101)+in+B-cell+lymphoma+patients.">Phase 1 study results of the type II glycoengineered humanized anti-CD20 monoclonal antibody obinutuzumab (GA101) in B-cell lymphoma patients.</a> Blood. 119 (22), 5126-5132 (2012).</li><li>Terszowski, G., Klein, C., Stern, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=KIR/HLA+interactions+negatively+affect+rituximab-+but+not+GA101+(obinutuzumab)-induced+antibody-dependent+cellular+cytotoxicity.">KIR/HLA interactions negatively affect rituximab- but not GA101 (obinutuzumab)-induced antibody-dependent cellular cytotoxicity.</a> J Immunol. 192 (12), 5618-5624 (2014).</li><li>Hsu, A. K., 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+immunostimulatory+effect+of+lenalidomide+on+NK-cell+function+is+profoundly+inhibited+by+concurrent+dexamethasone+therapy.">The immunostimulatory effect of lenalidomide on NK-cell function is profoundly inhibited by concurrent dexamethasone therapy.</a> Blood. 117 (5), 1605-1613 (2011).</li><li>Salih, 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=The+BCR/ABL-inhibitors+imatinib,+nilotinib+and+dasatinib+differentially+affect+NK+cell+reactivity.">The BCR/ABL-inhibitors imatinib, nilotinib and dasatinib differentially affect NK cell reactivity.</a> Int J Cancer. 127 (9), 2119-2128 (2010).</li><li>Benson, D. 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=A+phase+1+trial+of+the+anti-KIR+antibody+IPH2101+in+patients+with+relapsed/refractory+multiple+myeloma.">A phase 1 trial of the anti-KIR antibody IPH2101 in patients with relapsed/refractory multiple myeloma.</a> Blood. 120 (22), 4324-4333 (2012).</li><li>Vey, 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=A+phase+1+trial+of+the+anti-inhibitory+KIR+mAb+IPH2101+for+AML+in+complete+remission.">A phase 1 trial of the anti-inhibitory KIR mAb IPH2101 for AML in complete remission.</a> Blood. 120 (22), 4317-4323 (2012).</li><li>Terme, M., Ullrich, E., Delahaye, N. 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The authors have nothing to disclose.

The described method is an easy, fast and reliable approach to study NK cell functions from whole blood samples of healthy donors or patients. This method offers the great advantage to directly purify NK cells from whole blood, avoiding the time-consuming density gradient centrifugation, which is mandatory for many other purification methods15. Moreover, it requires a smaller sample size compared to &#34;classical&#34; NK cell isolation/enrichment methods, which makes it a suitable alternative for samples of p...

As part of the innate immune system natural killer (NK) cells contribute to the first line of defense against virus-infected or malignantly transformed cells. A system of inhibitory and activating receptors enables them to distinguish between healthy and transformed cells without prior antigen priming in contrast to T cells. Upon target cell encounter NK cells release the content of their cytotoxic granules (e.g., perforin, granzymes) into the immune synapse to kill their target. Moreover, NK cells produce and secrete different kinds of cytokines (e.g., interferon- &#947;: IFN-&#947;; tumor necrosis factor-&#945;: TNF-&#945;) and chemokines (e.g., macrophage inflammatory protein-1&#946;: MIP-1&#946;) upon target cell interaction or cytokine stimulation1.
Sufficient NK cell functions such as cytotoxicity, chemokine and cytokine production have an important impact on the fate of diverse diseases. Leukemia patients show increased relapse rates if they exhibit a defective NK cell profile at diagnosis consisting of reduced IFN-&#947; production and reduced expression of activating NK cell receptors2. An early recovery of NK cell numbers and function including cytokine production upon target cell interaction is associated with a reduced relapse and improved survival rate in patients receiving allogeneic stem cell transplantation3. Moreover, upon initiation of interferon therapy in hepatitis C virus-infected patients the degranulation capacity of peripheral NK cells is stronger in early responders than in non-responders4. NK cell numbers (&#62;80/&#181;l) on day 15 after autologous stem cell transplantation (autoSCT) in patients suffering from lymphoma or multiple myeloma are predictive for an improved progression free and overall survival5. In melanoma patients the expression of the T-cell immunoglobulin- and mucin-domain-containing molecule-3 (TIM-3), an immune-regulatory protein on NK cells, correlates with disease stage and prognosis6.
Scientists have monitored NK cell functions throughout the last decades. The initial analysis of NK cell cytotoxicity against tumor cells without prior priming was addressed using a 51Cr-release assay7. More recently, scientists developed a non-radioactive method to evaluate the cytotoxicity of expanded NK cells8. Cytokine and chemokine production has been frequently evaluated using enzyme-linked immunosorbent assay (ELISA) techniques9,10. During the last decades these methods have been complemented by flow cytometry-based assays. The use of protein transport inhibitors (e.g., brefeldin A and monensin) and cell permeabilization methods in combination with conventional surface staining protocols have enabled scientists to study chemokine and cytokine production in different specific lymphocyte subsets (e.g., T, B or NK cells)11. Moreover, different flow cytometry-based assays have been developed to monitor T and NK cell cytotoxicity. In 2004 Alter et al. described the surface expression of the lysosome-associated protein CD107a (Lamp1) on NK cells upon target cell encounter as a marker for the degranulation of cytotoxic granules12. Since a wide range of different fluorochromes and multi-channel flow cytometers are available in our days, it has become possible to simultaneously monitor diverse NK cell functions (cytotoxicity, cytokine and chemokine production) in different NK cell subsets. This becomes especially important in situations where sample size is limited, e.g., in biopsies or blood samples of patients suffering from leukopenia.
To test global NK cell functions, the different flow cytometry-based assays can be efficiently combined. Theorell et al. stimulated NK cells from healthy donors with the tumor cell line K562 and analyzed NK cell degranulation, inside-out signal and chemokine production via flow cytometry13. Recently NK cell subgroups, phenotypes and functions in tumor patients during autoSCT were analyzed using flow cytometry-based assays. It was demonstrated that NK cells were able to degranulate and produce cytokines/chemokines upon tumor cell recognition at very early time points after autoSCT11.
Here a protocol is described to evaluate NK cell functions upon interaction with tumor cells including degranulation capacity, chemokine and cytokine production using a flow cytometry-based assay that makes it possible to monitor NK cell functions in different subsets simultaneously.

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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">RPMI 1640 + glutamine</td>
			<td style="width:135px;">Invitrogen</td>
			<td style="width:119px;">6187-044</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">penicilin/streptomycin</td>
			<td style="width:135px;">Invitrogen</td>
			<td style="width:119px;">15140-122</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">BD Falcon Round Bottom Tube</td>
			<td style="width:135px;">BD</td>
			<td style="width:119px;">352008</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">fetal calf serum</td>
			<td style="width:135px;">Invitrogen</td>
			<td style="width:119px;">10270-106</td>
			<td style="width:167px;">heat inactivated before use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">T-flask</td>
			<td style="width:135px;">Greiner Bio-One</td>
			<td style="width:119px;">690195</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">K562 tumor cell line</td>
			<td style="width:135px;">DSMZ GmbH</td>
			<td style="width:119px;">ACC 10</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">ammonium-chloride-potassium (ACK) lysis buffer</td>
			<td style="width:135px;">made in house</td>
			<td style="width:119px;">/</td>
			<td style="width:167px;">components are listed in the text</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Distilled water: Ampuwa Sp&#252;ll&#246;sung 1000ml Plastipur</td>
			<td style="width:135px;">Fresenius Kabi</td>
			<td style="width:119px;">1088813</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Megafuge 40R Centrifuge</td>
			<td>Heraeus</td>
			<td style="width:119px;">/</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">EDTA blood collector tubes</td>
			<td style="width:135px;">Sarstedt</td>
			<td style="width:119px;">386453</td>
			<td style="width:167px;">S-Monovette 7,5 ml, K3 EDTA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">UltraPure 0.5M EDTA, pH 8.0</td>
			<td>Life Technologies</td>
			<td style="width:119px;">15575-020</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Hematopoietic media (XVIVO)</td>
			<td>Lonza Group Ltd</td>
			<td style="width:119px;">BE04-743Q</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">human serum</td>
			<td style="width:135px;">DRK Blutspendedienst, Frankfurt/M&#160;</td>
			<td style="width:119px;">/</td>
			<td style="width:167px;">healthy donors with blood type AB; heat inactivated before use</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Neubauer-improved counting chamber, bright line</td>
			<td style="width:135px;">Marienfeld superior/ LO-Laboroptik Ltd.</td>
			<td style="width:119px;">0640030/ 1110000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">trypan blue solution (0,4%)</td>
			<td>Invitrogen</td>
			<td style="width:119px;">15250-061</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">3% acetic acid with methylene blue</td>
			<td style="width:135px;">Stemcell Technologies&#160;</td>
			<td style="width:119px;">07060</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Corning 96 Well Clear V-Bottom TC-treated Microplates</td>
			<td style="width:135px;">Corning&#160;</td>
			<td style="width:119px;">3894</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Falcon 96 Well Round Bottom Not Treated Microplates</td>
			<td style="width:135px;">Corning&#160;</td>
			<td style="width:119px;">351177</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">DPBS (Ca2+- and Mg2+-free)</td>
			<td style="width:135px;">Gibco Invitrogen</td>
			<td style="width:119px;">14190-169</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">BSA</td>
			<td style="width:135px;">Sigma Aldrich</td>
			<td style="width:119px;">A2153-100G</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">NaN3</td>
			<td style="width:135px;">Sigma Aldrich</td>
			<td style="width:119px;">08591-1ML-F</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">phorbol 12-myristate 13-acetate (PMA)&#160;</td>
			<td style="width:135px;">Merck</td>
			<td style="width:119px;">524400-1MG</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">ionomycin&#160;</td>
			<td style="width:135px;">PromoKine</td>
			<td style="width:119px;">PK-CA577-1566-5</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">interleukin 15 (IL-15)</td>
			<td>PeproTech</td>
			<td>200-15</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Proleukin S (IL-2)&#160;</td>
			<td style="width:135px;">Novartis Pharma</td>
			<td style="width:119px;">730523</td>
			<td></td>
		</tr>
		<tr height="126">
			<td height="126" style="height:126px;width:216px;">Golgi Stop, Protein Transport Inhibitor (containing Monensin)</td>
			<td style="width:135px;">BD Biosciences</td>
			<td style="width:119px;">554724</td>
			<td style="width:167px;">This product can be used in combination or instead of Golgi Plug. The best combination for the wished experimental setting has to be tested.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Golgi Plug, Protein Transport Inhibitor (containing Brefeldin A)</td>
			<td style="width:135px;">BD Biosciences</td>
			<td style="width:119px;">555029</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">paraformaldehyde</td>
			<td style="width:135px;">AppliChem</td>
			<td style="width:119px;">UN2209</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">saponin</td>
			<td style="width:135px;">Sigma Aldrich</td>
			<td style="width:119px;">47036</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">flow cytometer: Canto10C</td>
			<td style="width:135px;">BD Biosciences</td>
			<td style="width:119px;">/</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">FlowJo</td>
			<td style="width:135px;">TreeStar Inc.</td>
			<td style="width:119px;">/</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Graph Pad</td>
			<td style="width:135px;">Graph Pad Inc.</td>
			<td style="width:119px;">/</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">MACSxpress Separator</td>
			<td style="width:135px;">Miltenyi Biotec&#160;</td>
			<td style="width:119px;">130-098-308</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">MACSxpress NK isolation kit</td>
			<td style="width:135px;">Miltenyi Biotec&#160;</td>
			<td style="width:119px;">130-098-185</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">MACSxpress Erythrocyte Depletion Kit, human</td>
			<td style="width:135px;">Miltenyi Biotec&#160;</td>
			<td style="width:119px;">130-098-196</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">MACSmix Tube Rotator&#160;</td>
			<td style="width:135px;">Miltenyi Biotec&#160;</td>
			<td style="width:119px;">130-090-753</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">anti-human CD3 APC</td>
			<td style="width:135px;">Biolegend</td>
			<td>300412</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">anti-human CD3 V450</td>
			<td style="width:135px;">BD Biosciences</td>
			<td>560366</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">anti-human CD14 PerCP</td>
			<td style="width:135px;">Miltenyi Biotec&#160;</td>
			<td>130-094-969</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">anti-human CD14 V450</td>
			<td style="width:135px;">BD Biosciences</td>
			<td>560349</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">anti-human CD16 PE</td>
			<td style="width:135px;">Biolegend</td>
			<td>302008</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">anti-human CD16 PerCP</td>
			<td style="width:135px;">Biolegend</td>
			<td>302029</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">anti-human CD19 PE-Cy7</td>
			<td style="width:135px;">Biolegend</td>
			<td>302216</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">anti-human CD19 V450</td>
			<td style="width:135px;">BD Biosciences</td>
			<td>560353</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">anti-human CD45 BV510</td>
			<td style="width:135px;">BD Biosciences</td>
			<td>563204</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">anti-human CD56 FITC</td>
			<td style="width:135px;">Biolegend</td>
			<td>345811</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">anti-human CD107a PE</td>
			<td style="width:135px;">Biolegend</td>
			<td>328608</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">anti-human IFN-&#947; AF-647</td>
			<td style="width:135px;">BD Biosciences</td>
			<td>557729</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">anti-human MIP-1&#946; APC-H7</td>
			<td style="width:135px;">BD Biosciences</td>
			<td>561280</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">DAPI</td>
			<td style="width:135px;">Biolegend</td>
			<td>422801</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Zombie Violet Fixable Viability Kit</td>
			<td>Biolegend</td>
			<td>423113</td>
			<td>fixable dead cell marker</td>
		</tr>
	</tbody>
</table>

flow cytometry-based assay for the monitoring of nk cell functions

Natural killer (NK) cells are an important part of the human tumor immune surveillance system. NK cells are able to distinguish between healthy and virus-infected or malignantly transformed cells due to a set of germline encoded inhibitory and activating receptors. Upon virus or tumor cell recognition a variety of different NK cell functions are initiated including cytotoxicity against the target cell as well as cytokine and chemokine production leading to the activation of other immune cells. It has been demonstrated that accurate NK cell functions are crucial for the treatment outcome of different virus infections and malignant diseases. Here a simple and reliable method is described to analyze different NK cell functions using a flow cytometry-based assay. NK cell functions can be evaluated not only for the whole NK cell population, but also for different NK cell subsets. This technique enables scientists to easily study NK cell functions in healthy donors or patients in order to reveal their impact on different malignancies and to further discover new therapeutic strategies.

The gating strategy for analyzing the degranulation, cytokine and chemokine production of the whole NK cell population and three different NK cell subsets are illustrated in Figure 1.
Representative results of one healthy donor are illustrated in Figure 2. NK cells without any stimulus produced neither IFN-&#947; nor MIP-1&#946; and did not express CD107a on their surface (Figure 2A</str...

Watch this Scientific Journal Video about Flow Cytometry-based Assay for the Monitoring of NK Cell Functions at JoVE.com

Flow Cytometry-based Assay for the Monitoring of NK Cell Functions

A simple and reliable method is described here to analyze a set of NK cell functions such as degranulation, cytokine and chemokine production within different NK cell subsets.

Natural killer (NK) cells are an important part of the human tumor immune surveillance system. NK cells are able to distinguish between healthy and ...

flow-cytometry-based-assay-for-the-monitoring-of-nk-cell-functions

Research

JoVE Journal

Immunology and Infection

20.7K Views.  Johann Wolfgang Goethe-University. A simple and reliable method is described here to analyze a set of NK cell functions such as degranulation, cytokine and chemokine production within different NK cell subsets.

Video: Flow Cytometry-based Assay for the Monitoring of NK Cell Functions

Detection of Infectious Virus from Field-collected Mosquitoes by Vero Cell Culture Assay

Mosquitoes transmit a number of distinct viruses including important human pathogens such as West Nile virus, dengue virus, and chickungunya virus. Many of these viruses have intensified in their endemic ranges and expanded to new territories, necessitating effective surveillance and control programs to respond to these threats. One strategy to monitor virus activity involves collecting large numbers of mosquitoes from endemic sites and testing them for viral infection. In this article, we describe how to handle, process, and screen field-collected mosquitoes for infectious virus by Vero cell culture assay. Mosquitoes are sorted by trap location and species, and grouped into pools containing &le;50 individuals. Pooled specimens are homogenized in buffered saline using a mixer-mill and the aqueous phase is inoculated onto confluent Vero cell cultures (Clone E6). Cell cultures are monitored for cytopathic effect from days 3-7 post-inoculation and any viruses grown in cell culture are identified by the appropriate diagnostic assays. By utilizing this approach, we have isolated 9 different viruses from mosquitoes collected in Connecticut, USA, and among these, 5 are known to cause human disease. Three of these viruses (West Nile virus, Potosi virus, and La Crosse virus) represent new records for North America or the New England region since 1999. The ability to detect a wide diversity of viruses is critical to monitoring both established and newly emerging viruses in the mosquito population.

We describe a method to process and screen field-collected mosquitoes for a diversity of viruses by Vero cell culture assay. By employing this technique, we have detected 9 different viruses from 4 taxonomic families in mosquitoes collected in Connecticut.

Mosquitoes transmit a number of distinct viruses including important human pathogens such as West Nile virus, dengue virus, and chickungunya virus. Many ...

Monitoring Dendritic Cell Migration using 19F / 1H Magnetic Resonance Imaging

Continuous advancements in noninvasive imaging modalities such as magnetic resonance imaging (MRI) have greatly improved our ability to study physiological or pathological processes in living organisms. MRI is also proving to be a valuable tool for capturing transplanted cells in vivo. Initial cell labeling strategies for MRI made use of contrast agents that influence the MR relaxation times (T1, T2, T2*) and lead to an enhancement (T1) or depletion (T2*) of signal where labeled cells are present. T2* enhancement agents such as ultrasmall iron oxide agents (USPIO) have been employed to study cell migration and some have also been approved by the FDA for clinical application. A drawback of T2* agents is the difficulty to distinguish the signal extinction created by the labeled cells from other artifacts such as blood clots, micro bleeds or air bubbles. In this article, we describe an emerging technique for tracking cells in vivo that is based on labeling the cells with fluorine (19F)-rich particles. These particles are prepared by emulsifying perfluorocarbon (PFC) compounds and then used to label cells, which subsequently can be imaged by 19F MRI. Important advantages of PFCs for cell tracking in vivo include (i) the absence of carbon-bound 19F in vivo, which then yields background-free images and complete cell selectivityand(ii) the possibility to quantify the cell signal by 19F MR spectroscopy.

Monitoring Dendritic Cell Migration using 19F / 1H Magnetic Resonance Imaging

Tracking of cells using MRI has gained remarkable attention in the past years. This protocol describes the labeling of dendritic cells with fluorine (19F)-rich particles, the in vivo application of these cells, and monitoring the extent of their migration to the draining lymph node with 19F/1H MRI and 19F MRS.

Continuous  advancements in noninvasive imaging modalities such as magnetic resonance  imaging (MRI) have greatly improved our ability to study ...

Cell-based Flow Cytometry Assay to Measure Cytotoxic Activity

Cytolytic activity of CD8+ T cells is rarely evaluated. We describe here a new cell-based assay to measure the capacity of antigen-specific CD8+ T cells to kill CD4+ T cells loaded with their cognate peptide. Target CD4+ T cells are divided into two populations, labeled with two different concentrations of CFSE. One population is pulsed with the peptide of interest (CFSE-low) while the other remains un-pulsed (CFSE-high). Pulsed and un-pulsed CD4+ T cells are mixed at an equal ratio and incubated with an increasing number of purified CD8+ T cells. The specific killing of autologous target CD4+ T cells is analyzed by flow cytometry after coculture with CD8+ T cells containing the antigen-specific effector CD8+ T cells detected by peptide/MHCI tetramer staining. The specific lysis of target CD4+ T cells measured at different effector versus target ratios, allows for the calculation of lytic units, LU30/106 cells. This simple and straightforward assay allows for the accurate measurement of the intrinsic capacity of CD8+ T cells to kill target CD4+ T cells.

This protocol describes a sensitive, cell-based cytotoxicity assay. By enumerating the decrease in frequency of live target CD4+ T cells in the presence of an increasing number of effector CD8+ T cells, this assay allows for the direct assessment of cytolytic activity of antigen-specific CD8+ T cells.

Cytolytic activity of CD8+ T cells is rarely evaluated. We describe here a new cell-based assay to measure the capacity of antigen-specific CD8+ T cells ...

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 ...

Fluorescence-activated Cell Sorting for Purification of Plasmacytoid Dendritic Cells from the Mouse Bone Marrow

Fluorescence-activated cell sorting (FACS) is a technique to purify specific cell populations based on phenotypes detected by flow cytometry. This method enables researchers to better understand the characteristics of a single cell population without the influence of other cells. Compared to other methods of cell enrichment, such as magnetic-activated cell sorting (MCS), FACS is more flexible and accurate for cell separation due to the ability of phenotype detection by flow cytometry. In addition, FACS is usually capable of separating multiple cell populations simultaneously, which improves the efficiency and diversity of experiments. Although FACS has some limitations, it has been broadly used to purify cells for functional studies in both in vitro and in vivo settings. Here we report a protocol using fluorescence-activated cell sorting to isolate a very rare population of immune cells, plasmacytoid dendritic cells (pDC), with high purity from the bone marrow of lupus-prone mice for in vitro functional studies of pDC.

We report a protocol using fluorescence-activated cell sorting to isolate plasmacytoid dendritic cells (pDC) with high purity from the bone marrow of lupus-prone mice for functional studies of pDC.

Fluorescence-activated cell sorting (FACS) is a technique to purify specific cell populations based on phenotypes detected by flow cytometry. This method ...

Assessing Retinal Microglial Phagocytic Function In Vivo Using a Flow Cytometry-based Assay

Microglia are the tissue resident macrophages of the central nervous system (CNS) and they perform a variety of functions that support CNS homeostasis, including phagocytosis of damaged synapses or cells, debris, and/or invading pathogens. Impaired phagocytic function has been implicated in the pathogenesis of diseases such as Alzheimer's and age-related macular degeneration, where amyloid-&#946; plaque and drusen accumulate, respectively. Despite its importance, microglial phagocytosis has been challenging to assess in vivo. Here, we describe a simple, yet robust, technique for precisely monitoring and quantifying the in vivo phagocytic potential of retinal microglia. Previous methods have relied on immunohistochemical staining and imaging techniques. Our method uses flow cytometry to measure microglial uptake of fluorescently labeled particles after intravitreal delivery to the eye in live rodents. This method replaces conventional practices that involve laborious tissue sectioning, immunostaining, and imaging, allowing for more precise quantification of microglia phagocytic function in just under six hours. This procedure can also be adapted to test how various compounds alter microglial phagocytosis in physiological settings. While this technique was developed in the eye, its use is not limited to vision research.

Assessing Retinal Microglial Phagocytic Function In Vivo Using a Flow Cytometry-based Assay

Microglial phagocytosis is critical for the maintenance of tissue homeostasis and inadequate phagocytic function has been implicated in pathology. However, assessing microglia function in vivo is technically challenging. We have developed a simple but robust technique for precisely monitoring and quantifying the phagocytic potential of microglia in a physiological setting.

Microglia are the tissue resident macrophages of the central nervous system (CNS) and they perform a variety of functions that support CNS homeostasis, ...

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 ...

A Flow Cytometry-Based Cytotoxicity Assay for the Assessment of Human NK Cell Activity

Within the innate immune system, effector lymphocytes known as natural killer (NK) cells play an essential role in host defense against aberrant cells, specifically eliminating tumoral and virally infected cells. Approximately 30 known monogenic defects, together with a host of other pathological conditions, cause either functional or classic NK cell deficiency, manifesting in reduced or absent cytotoxic activity. Historically, cytotoxicity has been investigated with radioactive methods, which are cumbersome, expensive and potentially hazardous. This article describes a streamlined, clinically applicable flow cytometry-based method to quantify NK cell cytotoxic activity. In this assay, peripheral blood mononuclear cells (PBMCs) or purified NK cell preparations are co-incubated at different ratios with a target tumor cell line known to be sensitive to NK cell-mediated cytotoxicity (NKCC). The target cells are pre-labeled with a fluorescent dye to allow their discrimination from the effector cells (NK cells). After the incubation period, killed target cells are identified by a nucleic acid stain, which specifically permeates dead cells. This method is amenable to both diagnostic and research applications and, thanks to the multi-parameter capabilities of flow cytometry, has the added advantage of potentially enabling a deeper analysis of NK cell phenotype and function.

A flow cytometry-based method to quantitatively determine the cytotoxic activity of human natural killer cells is shown here.

Within the innate immune system, effector lymphocytes known as natural killer (NK) cells play an essential role in host defense against aberrant cells, ...

A Simple Flow Cytometry Based Assay to Determine In Vitro Antibody Dependent Enhancement of Dengue Virus Using Zika Virus Convalescent Serum

Antibody dependent enhancement of infection has been shown to play a major role in Dengue viral pathogenesis. Traditional assays that measure the capacity of antibodies or serum to enhance infection in impermissible cell lines have relied on using viral output in the media followed by plaque assays to quantify infection. More recently, these assays have examined Dengue virus (DENV) infection in the cell lines using fluorescently labeled antibodies. Both these approaches have limitations that restrict the widespread use of these techniques. Here, we describe a simple in vitro assay using Dengue virus reporter viral particles (RVPs) that express green fluorescent protein and K562 cells to examine antibody dependent enhancement (ADE) of DENV infection using serum that was obtained from rhesus macaques 16 weeks after infection with Zika virus (ZIKV). This technique is reliable, involves minimal manipulation of cells, does not involve the use of live replication competent virus, and can be performed in a high throughput format to get a quantitative readout using flow cytometry. Additionally, this assay can be easily adapted to examine antibody dependent enhancement (ADE) of other flavivirus infections such as Yellow Fever virus (YFV), Japanese Equine Encephalitis virus (JEEV), West Nile virus (WNV) etc. where RVPs are available. The ease of setting up the assay, analyzing the data, and interpreting results makes it highly amenable to most laboratory settings.

A Simple Flow Cytometry Based Assay to Determine In Vitro Antibody Dependent Enhancement of Dengue Virus Using Zika Virus Convalescent Serum

We describe a simple and easy protocol for measuring antibody dependent enhancement of infection by Zika virus convalescent serum using Dengue virus Reporter Viral Particles.

Antibody dependent enhancement of infection has been shown to play a major role in Dengue viral pathogenesis. Traditional assays that measure the capacity ...

Multicolor Flow Cytometry-based Quantification of Mitochondria and Lysosomes in T Cells

T cells utilize different metabolic programs to match their functional needs during differentiation and proliferation. Mitochondria are crucial cellular components responsible for supplying cell energy; however, excess mitochondria also produce reactive oxygen species (ROS) that could cause cell death. Therefore, the number of mitochondria must constantly be adjusted to fit the needs of the cells. This dynamic regulation is achieved in part through the function of lysosomes that remove surplus/damaged organelles and macromolecules. Hence, cellular mitochondrial and lysosomal contents are key indicators to evaluate the metabolic adjustment of cells. With the development of probes for organelles, well-characterized lysosome or mitochondria-specific dyes have become available in various formats to label cellular lysosomes and mitochondria. Multicolor flow cytometry is a common tool to profile cell phenotypes, and has the capability to be integrated with other assays. Here, we present a detailed protocol of how to combine organelle-specific dyes with surface markers staining to measure the amount of lysosomes and mitochondria in different T cell populations on a flow cytometer.

This article illustrates a powerful method to quantify mitochondria or lysosomes in living cells. The combination of lysosome- or mitochondria-specific dyes with fluorescently conjugated antibodies against surface markers allows the quantification of these organelles in mixed cell populations, like primary cells harvested from tissue samples, by using multicolor flow cytometry.

T cells utilize different metabolic programs to match their functional needs during differentiation and proliferation. Mitochondria are crucial cellular ...