Conditioned cell media were centrifuged at 300 g (for 10 min) and filtered through a 5-µm syringe-filter (Millex, Millipore) in order to remove cell debris and apoptotic bodies. The resulting supernatants were stained with the FITC-conjugated isolectine B4 from Bandeiraea simplicifolia (Sigma-Aldrich), previously centrifuged at 13,000 g for 30 min for discarding aggregates. Calibration beads (BioCytex) of known dimensions (from 0.1 to 0.9 µm) were used to define the gate into which IB4+ events can be considered as bona fide MVs. Samples were acquired at Accuri C6 (BD Biosciences).