ATCC Cell Systems 1 article published in JoVE Immunology and Infection Purification of High Yield Extracellular Vesicle Preparations Away from Virus Catherine DeMarino*1, Robert A. Barclay*1, Michelle L. Pleet1, Daniel O. Pinto1, Heather Branscome1,2, Siddhartha Paul3, Benjamin Lepene4, Nazira El-Hage5, Fatah Kashanchi1 1Laboratory of Molecular Virology, School of Systems Biology, George Mason University, 2American Type Culture Collection (ATCC), 3ATCC Cell Systems, 4Ceres Nanosciences, Inc, 5Department of Immunology and Nano-medicine, Herbert Wertheim College of Medicine, Florida International University This protocol isolates extracellular vesicles (EVs) away from virions with high efficiency and yield by incorporating EV precipitation, density gradient ultracentrifugation, and particle capture to allow for a streamlined workflow and a reduction of starting volume requirements, resulting in reproducible preparations for use in all EV research.