@article{59, author = {Leonie de Rond and Edwin Van der Pol and Chi Hau and Zoltán Varga and Auguste Sturk and Ton van Leeuwen and Rienk Nieuwland and Frank Coumans}, title = {Comparison of Generic Fluorescent Markers for Detection of Extracellular Vesicles by Flow Cytometry}, abstract = {BACKGROUND: Extracellular vesicles (EVs) in biofluids are potential biomarkers of disease. To explore the clinical relevance of EVs, a specific generic EV marker would be useful, one that does not require antibodies and binds to all EVs. Here we evaluated 5 commonly used generic markers for flow cytometry. METHODS: Flow cytometry (A60-Micro, Apogee) was used to evaluate the ability of the generic EV markers calcein acetoxymethyl ester, calcein acetoxymethyl ester violet, carboxyfluorescein succinimidyl ester (CFSE), 4-(2-[6-(dioctylamino)-2-naphthalenyl] ethenyl)1-(3-sulfopropyl) pyridinium (di-8-ANEPPS), and lactadherin to stain EVs from MCF7 human breast adenocarcinoma cell line-conditioned culture medium [epithelial cell adhesion molecule positive (EpCAM(+))] or platelet EVs from human plasma [integrin beta 3 positive (CD61(+))]. Side scatter triggering was applied as a reference, and the influence of non-EV components (proteins and lipoproteins) was evaluated. RESULTS: Di-8-ANEPPS, lactadherin, and side scatter detected 100% of EpCAM(+) MCF7 EVs. Lactadherin and side scatter detected 33% and 61% of CD61(+) EVs, respectively. Di-8-ANEPPS detected platelet EVs only if soluble protein was first removed. Because all generic markers stained proteins, at best 33% of platelet EVs in plasma were detected. The calcein markers and CFSE were either insensitive to EVs in both samples or associated with swarm detection. CONCLUSIONS: None of the generic markers detected all and only EVs in plasma. Side scatter triggering detected the highest concentration of plasma EVs on our A60-Micro, followed by lactadherin. The choice between scatter or lactadherin primarily depends on the analytical sensitivity of the flow cytometer used. (c) 2018 American Association for Clinical Chemistry}, year = {2018}, journal = {CLINICAL CHEMISTRY}, volume = {64}, number = {4}, pages = {680–689}, issn = {0009-9147}, doi = {10.1373/clinchem.2017.278978}, }