High Purity Isolation and Sensitive Quantification of Extracellular Vesicles Using Affinity to TIM4

Almost all types of cells secrete extracellular vesicles (EVs), including exosomes and microvesicles. EVs carry various proteins, lipids, mRNAs, and microRNAs, and may participate in many aspects of physiological and pathophysiological processes. Various studies are currently being conducted to develop therapeutic and diagnostic methods targeting or utilizing EVs. Therefore, developing ideal methods for isolating and quantifying EVs is an active area of research. EVs express phosphatidylserine on their outer lipid bilayer. This unit describes an affinity-based method for isolating EVs using TIM4, which binds phosphatidylserine in a specific and calcium-dependent manner. EVs captured by TIM4 can be easily released by addition of a chelating agent, or can be retained for quantification by ELISA or flow cytometry. These methods enable the isolation of highly purified EVs and the sensitive quantification of EVs, which will accelerate EV research beyond what has been achievable with conventional methods. © 2017 by John Wiley & Sons, Inc.