Exosomes are small vesicles comprised of a lipid bilayer containing various proteins, RNAs and bioactive lipids. Recently, the importance of exosomes in disease has become more appreciated as research demonstrates the ability of exosomes to act as intercellular messengers, serve as biomarkers and be used as therapeutic delivery methods. Puriﬁcation and enumeration of small vesicles from biological ﬂuids often requires specialized equipment, an ultra-centrifuge and particle counter for example, which are not readily available to most clinical labs. KCAS, LLC optimized a protocol to isolate exosomes from human plasma using precipitation and characterize their phenotype using ﬂow cytometry. We were able to characterize and enumerate exosomes from diseased patients; immunophenotype was determined by the following panel: CA125, CD59, CD9, CD63, Annexin V (phosphatidylserine), human leukocyte antigen(HLA-) A, B and C cocktail. We demonstrate that we can successfully isolate exosomes and analyze them using ﬂow cytometry. The data provides support for clinical puriﬁcation and enumeration of exosomes using common laboratory equipment as well as phenotypic analysis by ﬂow cytometry.
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