Name: techniques for the analysis of extracellular vesicles using flow cytometry
Uploaded: 2015-03-17T15:00:00
Description: Watch this Scientific Journal Video about Techniques for the Analysis of Extracellular Vesicles Using Flow Cytometry at JoVE.com

The authors would like to thank Dale Hirschkorn from Blood Systems Research Institute for his help with flow cytometer instrument settings. This work was supported by NIH grants HL095470 and U01 HL072268 and DoD contracts W81XWH-10-1-0023 and W81XWH-2-0028.

NOTE: The following protocols have been performed in compliance with all institutional, national and international guidelines for human welfare. All human subject samples were tested under an institutional review board (IRB)-approved protocol and with informed consent of the subjects.
1. METHOD A: Individual Detection Method
1.1) Processing of Blood Sample/Isolation of EVs
<ol>
	<li>Draw blood from donor/patient into two 10 ml glass tubes containing 1.5 ml of ACD-Sol...

<ol>
	<li>Andaloussi, S., M&#228;ger, I., Breakefield, X. O., Wood, M. J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+vesicles:+biology+and+emerging+therapeutic+opportunities.">Extracellular vesicles: biology and emerging therapeutic opportunities.</a> Nature Reviews Drug Discovery. 12 (5), 347-357 (2013).</li><li>Sugawara, A., Nollet, K. E., Yajima, K., Saito, S., Ohto, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preventing+platelet-derived+microparticle+formation--and+possible+side+effects-with+prestorage+leukofiltration+of+whole+blood.">Preventing platelet-derived microparticle formation--and possible side effects-with prestorage leukofiltration of whole blood.</a> Archives of Pathology &amp; Laboratory Medicine. 134 (5), 771-775 (2010).</li><li>Th&#233;ry, C., Ostrowski, M., Segura, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Membrane+vesicles+as+conveyors+of+immune+responses.">Membrane vesicles as conveyors of immune responses.</a> Nature Reviews Immunology. 9 (8), 581-593 (2009).</li><li>Mause, S. 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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exosomes+Released+by+Melanoma+Cells+Prepare+Sentinel+Lymph+Nodes+for+Tumor+Metastasis.">Exosomes Released by Melanoma Cells Prepare Sentinel Lymph Nodes for Tumor Metastasis.</a> Cancer Research. 71 (11), 3792-3801 (2011).</li><li>Gatti, S., Bruno, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microvesicles+derived+from+human+adult+mesenchymal+stem+cells+protect+against+ischaemia-reperfusion-induced+acute+and+chronic+kidney+injury.">Microvesicles derived from human adult mesenchymal stem cells protect against ischaemia-reperfusion-induced acute and chronic kidney injury.</a> Nephrology Dialysis Transplantation. 26 (5), 1474-1483 (2011).</li><li>Barteneva, N. 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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow+cytometric+measurement+of+microparticles:+Pitfalls+and+protocol+modifications.">Flow cytometric measurement of microparticles: Pitfalls and protocol modifications.</a> Platelets. 19 (5), 365-372 (2008).</li><li>Dey-Hazra, E., Hertel, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+circulating+microparticles+by+flow+cytometry:+influence+of+centrifugation,+filtration+of+buffer,+and+freezing.">Detection of circulating microparticles by flow cytometry: influence of centrifugation, filtration of buffer, and freezing.</a> Vascular Health and Risk Management. 6, 1125-1133 (2010).</li><li>Lacroix, R., Judicone, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standardization+of+pre-analytical+variables+in+plasma+microparticle+determination:+results+of+the+International+Society+on+Thrombosis+and+Haemostasis+SSC+Collaborative+workshop.">Standardization of pre-analytical variables in plasma microparticle determination: results of the International Society on Thrombosis and Haemostasis SSC Collaborative workshop.</a> Journal of Thrombosis and Haemostasis. 11 (6), 1190-1193 (2013).</li><li>Mullier, F., Bailly, N., Chatelain, C., Chatelain, B., Dogn&#233;, J. -. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pre-analytical+issues+in+the+measurement+of+circulating+microparticles:+current+recommendations+and+pending+questions.">Pre-analytical issues in the measurement of circulating microparticles: current recommendations and pending questions.</a> Journal of Thrombosis and Haemostasis. 11 (4), 693-696 (2013).</li><li>Peramo, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physical+Characterization+of+Mouse+Deep+Vein+Thrombosis+Derived+Microparticles+by+Differential+Filtration+with+Nanopore+Filters.">Physical Characterization of Mouse Deep Vein Thrombosis Derived Microparticles by Differential Filtration with Nanopore Filters.</a> Membranes. 2 (1), 1-15 (2012).</li><li>Tilley, R. E., Holscher, T., Belani, R., Nieva, J., Mackman, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+Factor+Activity+is+Increased+in+a+Combined+Platelet+and+Microparticle+Sample+from+Cancer+Patients.">Tissue Factor Activity is Increased in a Combined Platelet and Microparticle Sample from Cancer Patients.</a> Thrombosis research. 122 (5), 604-609 (2008).</li><li>Rood, I. M., Deegens, J. K. 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=Comparison+of+three+methods+for+isolation+of+urinary+microvesicles+to+identify+biomarkers+of+nephrotic+syndrome.">Comparison of three methods for isolation of urinary microvesicles to identify biomarkers of nephrotic syndrome.</a> Kidney international. 78 (8), 810-816 (2010).</li><li>Van der Pol, E., Hoekstra, A. G., Sturk, A., Otto, C., van Leeuwen, T. G., Nieuwland, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+and+non-optical+methods+for+detection+and+characterization+of+microparticles+and+exosomes.">Optical and non-optical methods for detection and characterization of microparticles and exosomes.</a> Journal of Thrombosis And Haemostasis: JTH. 8 (12), 2596-2607 (2010).</li><li>Gy&#246;rgy, B., Szab&#243;, T. 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=Membrane+vesicles,+current+state-of-the-art:+emerging+role+of+extracellular+vesicles.">Membrane vesicles, current state-of-the-art: emerging role of extracellular vesicles.</a> Cellular and Molecular Life Sciences. 68 (16), 2667-2688 (2011).</li><li>Miguet, L., Be&#769;chade, 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=Proteomic+Analysis+of+Malignant+B-Cell+Derived+Microparticles+Reveals+CD148+as+a+Potentially+Useful+Antigenic+Biomarker+for+Mantle+Cell+Lymphoma+Diagnosis.">Proteomic Analysis of Malignant B-Cell Derived Microparticles Reveals CD148 as a Potentially Useful Antigenic Biomarker for Mantle Cell Lymphoma Diagnosis.</a> Journal of Proteome Research. 8 (7), 3346-3354 (2009).</li><li>Smalley, D. M., Root, K. E., Cho, H., Ross, M. M., Ley, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteomic+discovery+of+21+proteins+expressed+in+human+plasma-derived+but+not+platelet-derived+microparticles.">Proteomic discovery of 21 proteins expressed in human plasma-derived but not platelet-derived microparticles.</a> Thrombosis and Haemostasis. 97 (1), 67-80 (2007).</li><li>Lacroix, R., Robert, S., Poncelet, P., Dignat-George, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overcoming+Limitations+of+Microparticle+Measurement+by+Flow+Cytometry.">Overcoming Limitations of Microparticle Measurement by Flow Cytometry.</a> Seminars in Thrombosis and Hemostasis. 36 (08), 807-818 (2010).</li><li>Mobarrez, F., Antovic, 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=A+multicolor+flow+cytometric+assay+for+measurement+of+platelet-derived+microparticles.">A multicolor flow cytometric assay for measurement of platelet-derived microparticles.</a> Thrombosis Research. 125 (3), e110-e116 (2010).</li><li>Van der Pol, E., van Gemert, M. J. C., Sturk, A., Nieuwland, R., van Leeuwen, T. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single+vs.+swarm+detection+of+microparticles+and+exosomes+by+flow+cytometry.">Single vs. swarm detection of microparticles and exosomes by flow cytometry.</a> Journal of Thrombosis And Haemostasis: JTH. 10 (5), 919-930 (2012).</li><li>Gy&#246;rgy, B., Szab&#243;, T. 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=Improved+Flow+Cytometric+Assessment+Reveals+Distinct+Microvesicle+(Cell-Derived+Microparticle)+Signatures+in+Joint+Diseases.">Improved Flow Cytometric Assessment Reveals Distinct Microvesicle (Cell-Derived Microparticle) Signatures in Joint Diseases.</a> PLoS ONE. 7 (11), e49726 (2012).</li><li>Gy&#246;rgy, B., M&#243;dos, 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=Detection+and+isolation+of+cell-derived+microparticles+are+compromised+by+protein+complexes+resulting+from+shared+biophysical+parameters.">Detection and isolation of cell-derived microparticles are compromised by protein complexes resulting from shared biophysical parameters.</a> Blood. 117 (4), e39-e48 (2011).</li><li>Gy&#246;rgy, B., Pasztoi, M., Buzas, E. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Response:+systematic+use+of+Triton+lysis+as+a+control+for+microvesicle+labeling.">Response: systematic use of Triton lysis as a control for microvesicle labeling.</a> Blood. 119 (9), 2175-2176 (2012).</li><li>Trummer, A., De Rop, C., Tiede, A., Ganser, A., Eisert, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isotype+controls+in+phenotyping+and+quantification+of+microparticles:+a+major+source+of+error+and+how+to+evade+it.">Isotype controls in phenotyping and quantification of microparticles: a major source of error and how to evade it.</a> Thrombosis Research. 122 (5), 691-700 (2008).</li><li>Shet, A. S., Aras, O., 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=Sickle+blood+contains+tissue+factor-positive+microparticles+derived+from+endothelial+cells+and+monocytes.">Sickle blood contains tissue factor-positive microparticles derived from endothelial cells and monocytes.</a> Blood. 102 (7), 2678-2683 (2003).</li><li>Connor, D. E., Exner, T., Ma, D. D. F., Joseph, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+majority+of+circulating+platelet-derived+microparticles+fail+to+bind+annexin+V,+lack+phospholipid-dependent+procoagulant+activity+and+demonstrate+greater+expression+of+glycoprotein+Ib.">The majority of circulating platelet-derived microparticles fail to bind annexin V, lack phospholipid-dependent procoagulant activity and demonstrate greater expression of glycoprotein Ib.</a> Thrombosis and Haemostasis. 103 (5), 1044-1052 (2010).</li><li>Nolte-&#8217;t Hoen, E. N. M., van der Vlist, E. 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Two different protocols for the isolation, treatment and analysis of EVs were presented, using either an individual detection or bead-based approach. Selecting the most appropriate method to use is not always straightforward and requires an understanding of the sample being tested as well as the individual subpopulations of interest. Furthermore, the sensitivity of the cytometer used for acquisition must be considered when choosing the most appropriate method. Oftentimes there is no single best protocol to use, rather, a...

Extracellular Vesicles (EVs) are small, membrane-derived vesicles found in bodily fluids that are highly involved in cell-cell communication and help regulate a diverse range of biological processes. Analysis of EVs using flow cytometry (FCM) has been notoriously difficult due to their small size and lack of discrete populations positive for markers of interest. Methods for EV analysis, while considerably improved over the last decade, are still a work in progress. Unfortunately, there is no one-size-fits-all protocol, and several aspects must be considered when determining the most appropriate method to use. Presented here are several different techniques for processing EVs and two protocols for analyzing EVs using either individual detection or a bead-based approach. The methods described here will assist with eliminating the antibody aggregates commonly found in commercial preparations, increasing signal&#8211;to-noise ratio, and setting gates in a rational fashion that minimizes detection of background fluorescence. The first protocol uses an individual detection method that is especially well suited for analyzing a high volume of clinical samples, while the second protocol uses a bead-based approach to capture and detect smaller EVs and exosomes. 
EVs, also known as microparticles, are small, membrane-derived vesicles found in bodily fluids that are involved in cell-cell communication and help regulate a diverse range of biological processes1. Through expression of various surface markers and/or direct transfer of biological material, EVs are able to alter the function of recipient cells to play either activating or suppressing roles in intercellular communication2&#8211;4. Clinically, platelet-derived EVs are known to have strong anticoagulant activity5, while others have been shown to contribute to a wide range of conditions, from promoting tumor metastasis6&#160;to protecting against disease7. EVs can be classified into smaller categories of cell-derived vesicles such as exosomes and microvesicles (MVs), depending on their size and mechanism of generation8. The nomenclature of cell-derived vesicle subpopulations continues to be a topic of ongoing debate8,9, however, exosomes are generally described as small, 40 to 100 nm particles derived from endosomal fusion with the plasma membrane, while MVs are larger 100 to 1,000 nm particles formed by shedding of the plasma membrane10. Here, the general term &#8220;EVs&#8221; will be used to refer to all types of extracellular biological vesicles released by cells.
Isolation of EVs from whole blood is a multi-step procedure and many different processing variables have been shown to affect EV content, including storage temperature and duration11,12, anticoagulant/preservative used13&#160;and centrifugation method used14. A need for standardization of these variables has led to recommendations by the International Society on Thrombosis and Haemostasis Scientific and Standardization Committee (ISTH SSC) for proper blood processing and EV isolation procedures15,16, yet there exists no consensus among researchers on the optimal protocol to use 12. Most agree, however, that tightly controlled pre-analytical variables are crucial for accurate and reproducible data.
In order to analyze EVs, researchers have utilized various methods, including transmission electron microscopy17, scanning electron microscopy18,19, atomic force microscopy, dynamic light scattering20,21&#160;and western blotting22,23. While FCM is the method of choice for many researchers9,24&#8211;26&#160;due to its high throughput capabilities, analysis of EVs using FCM has been notoriously difficult due to their size and lack of discrete positive populations27&#8211;32. Compared to analysis of cells, the small size of the EVs results in 1) less fluorescence emitted due to the fewer number of antigens per particle and 2) limited feasibility of post-stain washing, which is necessary to reduce background fluorescence. Common challenges among researchers include signals arising from immunoglobulin aggregates27,28and self-aggregation of antibodies29. Furthermore, the long processing times and lengthy washing/isolation procedures used by many of the current protocols33,34&#160;require multi-day time commitments to analyze a small number of samples, making them less than ideal for high throughput applications. Some researchers forgo a wash step altogether, rendering traditionally used FCM negative controls such as fluorescence minus one (FMO) and antibody isotypes useless for accurately assessing background fluorescence30.
Our protocols address three common problems that can impede proper FCM analysis of EVs: signals arising from antibody aggregates and other non-vesicles, difficulty in removing unbound antibody, and lack of discernible positive populations. The techniques described here will assist with eliminating the antibody aggregates commonly found in commercial preparations, increasing signal&#8211;to-noise ratio, and setting gates in a rational fashion that minimizes detection of background fluorescence. Two different detection methods are presented here: the first protocol uses an individual detection method that is especially well suited for analyzing a high volume of clinical samples, while the second protocol uses a beads-based approach to capture and detect smaller EVs and exosomes.

<table border="0" cellpadding="0" cellspacing="0" >
	<tbody>
		<tr >
			<td >LSR II benchtop flow cytometer</td>
			<td >BD Biosciences</td>
			<td ></td>
			<td >3-laser (20 mW Coherent Sapphire 488 nm blue, 25 mW Coherent Vioflame 405 nm violet, and 17 mW JDS Uniphase HeNe 633nm red)</td>
		</tr>
		<tr >
			<td >FACS Diva software&#160;</td>
			<td >BD Biosciences</td>
			<td ></td>
			<td >PC version 6.0</td>
		</tr>
		<tr >
			<td >FlowJo software&#160;</td>
			<td >Treestar US</td>
			<td ></td>
			<td >Mac version 9.6.1 or PC version 7.6.5</td>
		</tr>
		<tr >
			<td >Sphero Rainbow fluorescent particles</td>
			<td >BD Biosciences</td>
			<td >556298</td>
			<td >used to adjust all channel voltages to maintain fluorescence intensity consistency&#160;</td>
		</tr>
		<tr >
			<td >Ultra Rainbow fluorescent particles&#160;</td>
			<td >Spherotech</td>
			<td >URFP-10-5</td>
			<td >used in addition to Megamix-Plus SSC beads to ensure EV gating consistency from batch to batch</td>
		</tr>
		<tr >
			<td >Megmix-Plus SSC beads</td>
			<td >Biocytex</td>
			<td >7803</td>
			<td >used to adjust FSC and SSC&#160; voltages to maintain&#160; consistency&#160; between runs. Can also used to monitor flow rate and ajust flow rate dial in order to ensure that same flow rate is used in all runs</td>
		</tr>
		<tr >
			<td >AbC Anti-Mouse Bead Kit</td>
			<td >Life Technologies</td>
			<td >A-10344</td>
			<td >used for compensation controls &#38; negative AbC beads used for beads-based method</td>
		</tr>
		<tr >
			<td >Nonidet P-40 Alternative (NP-40) (CAS 9016-45-9)</td>
			<td >Santa Cruz&#160;</td>
			<td >sc-281108</td>
			<td >used in the individual detection method only to lyse samples after initial reading for use as negative controls. Stock may be diluted to 1:10 in PBS and stored in fridge for up to 1 month.</td>
		</tr>
		<tr >
			<td >BD TruCOUNT Tubes</td>
			<td >BD Biosciences</td>
			<td >340334</td>
			<td >used whenver absolute EV concentrations are needed</td>
		</tr>
		<tr >
			<td >Ultrafree-MC, GV 0.22 &#181;m Centrifugal Filter Units</td>
			<td >Millipore&#160;</td>
			<td >UFC30GVNB</td>
			<td >used to post-stain wash Evs and/or fractionate EVs based on size</td>
		</tr>
		<tr >
			<td >Vacutainer glass whole blood tubes ACD-A</td>
			<td >BD Biosciences</td>
			<td >364606</td>
			<td ></td>
		</tr>
		<tr >
			<td >Facs tubes 12x75 polystrene</td>
			<td >BD Biosciences</td>
			<td >352058</td>
			<td ></td>
		</tr>
		<tr >
			<td >50mL Reservoirs individually wrapped&#160;</td>
			<td >Phenix</td>
			<td >RR-50-1s</td>
			<td ></td>
		</tr>
		<tr >
			<td >Green-Pak pipet tips - 10&#181;L</td>
			<td >Rainin</td>
			<td >GP-L10S</td>
			<td ></td>
		</tr>
		<tr >
			<td >Green-Pak pipet tips -200&#181;L&#160;</td>
			<td >Rainin</td>
			<td >GP-L250S</td>
			<td ></td>
		</tr>
		<tr >
			<td >Green -Pak pipet tips - 1000&#181;L&#160;</td>
			<td >Rainin</td>
			<td >GP-L1000S</td>
			<td ></td>
		</tr>
		<tr >
			<td >Stable Stack L300 tips presterilized</td>
			<td >Rainin</td>
			<td >SS-L300S</td>
			<td ></td>
		</tr>
		<tr >
			<td >Pipet-Lite&#160;XLS 8 Channel LTS&#160;Adjustable&#160;Spacer&#160;</td>
			<td >Rainin</td>
			<td >LA8-300XLS</td>
			<td ></td>
		</tr>
		<tr >
			<td >96 well tissue culture plates</td>
			<td >E&#38;K Scientific</td>
			<td >EK-20180</td>
			<td ></td>
		</tr>
		<tr >
			<td >RPMI 1640 Media (without Hepes)</td>
			<td >UCSF Cell Culture Facility</td>
			<td >CCFAE001</td>
			<td >media used for bead-based detection method</td>
		</tr>
		<tr >
			<td >Dulbeccos PBS D-PBS, CaMg-free, 0.2&#181;m filtered</td>
			<td >UCSF Cell Culture Facility</td>
			<td >CCFAL003</td>
			<td ></td>
		</tr>
		<tr >
			<td >Ultracentrifuge Tube, Thinwall, Ultra-Clear</td>
			<td >BECKMAN COULTER INC</td>
			<td >344058</td>
			<td ></td>
		</tr>
		<tr >
			<td >PANEL I</td>
			<td ></td>
			<td ></td>
			<td ></td>
		</tr>
		<tr >
			<td >CD3 PerCP-Cy5.5</td>
			<td >Biolegend</td>
			<td >344808</td>
			<td >2 &#181;l</td>
		</tr>
		<tr >
			<td >CD14 APC-Cy7</td>
			<td >Biolegend</td>
			<td >301820</td>
			<td >2 &#181;l</td>
		</tr>
		<tr >
			<td >CD16 V450</td>
			<td >BD Biosciences</td>
			<td >560474</td>
			<td >2 &#181;l</td>
		</tr>
		<tr >
			<td >CD28 FITC</td>
			<td >biolegend</td>
			<td >302906</td>
			<td >2 &#181;l</td>
		</tr>
		<tr >
			<td >CD152 APC</td>
			<td >BD Biosciences</td>
			<td >555855</td>
			<td >2 &#181;l</td>
		</tr>
		<tr >
			<td >CD19 A700</td>
			<td >Biolegend</td>
			<td >302226</td>
			<td >2 &#181;l</td>
		</tr>
		<tr >
			<td >PANEL II</td>
			<td ></td>
			<td ></td>
			<td ></td>
		</tr>
		<tr >
			<td >CD41a PerCP-Cy5.5</td>
			<td >BD Biosciences</td>
			<td >340930</td>
			<td >2 &#181;l</td>
		</tr>
		<tr >
			<td >CD62L APC</td>
			<td >Biolegend</td>
			<td >304810</td>
			<td >2 &#181;l</td>
		</tr>
		<tr >
			<td >CD108 PE&#160;</td>
			<td >BD Biosciences</td>
			<td >552830</td>
			<td >2 &#181;l</td>
		</tr>
		<tr >
			<td >CD235a FITC</td>
			<td >biolegend</td>
			<td >349104</td>
			<td >2 &#181;l</td>
		</tr>
		<tr >
			<td >PANEL III</td>
			<td ></td>
			<td ></td>
			<td ></td>
		</tr>
		<tr >
			<td >CD11b PE-Cy7</td>
			<td >Biolegend</td>
			<td >301322</td>
			<td >2 &#181;l</td>
		</tr>
		<tr >
			<td >CD62p APC</td>
			<td >Biolegend</td>
			<td >304910</td>
			<td >2 &#181;l</td>
		</tr>
		<tr >
			<td >CD66b PE&#160;</td>
			<td >Biolegend</td>
			<td >305106</td>
			<td >2 &#181;l</td>
		</tr>
		<tr >
			<td >CD15 FITC</td>
			<td >exalpha</td>
			<td >X1496M</td>
			<td >5 &#181;l</td>
		</tr>
		<tr >
			<td >CD9 PE</td>
			<td >Biolegend</td>
			<td >555372</td>
			<td ></td>
		</tr>
		<tr >
			<td >CD63 APC</td>
			<td >Biolegend</td>
			<td >353008</td>
			<td ></td>
		</tr>
		<tr >
			<td >APC-Cy7 Ms IgG2a, &#954;</td>
			<td >Biolegend</td>
			<td >400230</td>
			<td ></td>
		</tr>
	</tbody>
</table>

techniques for the analysis of extracellular vesicles using flow cytometry

Extracellular Vesicles (EVs) are small, membrane-derived vesicles found in bodily fluids that are highly involved in cell-cell communication and help regulate a diverse range of biological processes. Analysis of EVs using flow cytometry (FCM) has been notoriously difficult due to their small size and lack of discrete populations positive for markers of interest. Methods for EV analysis, while considerably improved over the last decade, are still a work in progress. Unfortunately, there is no one-size-fits-all protocol, and several aspects must be considered when determining the most appropriate method to use. Presented here are several different techniques for processing EVs and two protocols for analyzing EVs using either individual detection or a bead-based approach. The methods described here will assist with eliminating the antibody aggregates commonly found in commercial preparations, increasing signal&#8211;to-noise ratio, and setting gates in a rational fashion that minimizes detection of background fluorescence. The first protocol uses an individual detection method that is especially well suited for analyzing a high volume of clinical samples, while the second protocol uses a bead-based approach to capture and detect smaller EVs and exosomes.

Figure 1 outlines the overall processing scheme for the isolation and detection of EVs using either the bead-based method or individual detection method. Individual detection of EVs using FCM works well for analyzing larger EVs but most cytometers are not capable of individually detecting particles as small as exosomes. A bead-based approach allows small EVs to be detected, however, there are drawbacks associated with using this method, as outlined in Table 1. Generally, isolation of EVs...

Watch this Scientific Journal Video about Techniques for the Analysis of Extracellular Vesicles Using Flow Cytometry at JoVE.com

Techniques for the Analysis of Extracellular Vesicles Using Flow Cytometry

Many different methods exist for the measurement of extracellular vesicles (EVs) using flow cytometry (FCM). Several aspects should be considered when determining the most appropriate method to use. Two protocols for measuring EVs are presented, using either individual detection or a bead-based approach.

Extracellular Vesicles (EVs) are small, membrane-derived vesicles found in bodily fluids that are highly involved in cell-cell communication and help ...

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