For cytometric analysis of vesicles, the CytoFLEX S by Beckman Coulter was used (CytExpert Version 2.4.0.28). Samples were diluted prior to measurement with PBS to achieve an abort rate below 10%. To account for small particle size compared to cells, the primary threshold (trigger level) and the width channel were set to SSC (height: 1000). 50000 events per sample were recorded and a gating strategy was applied to exclude debris (SSC-A [log] vs FSC-A [log]) and to analyse only single vesicles per event (SSC-A [log] vs SSC-Width [linear]). Fluorescence of mClover was measured in the FITC channel (525/40 nm) at maximum gain due to small particle size.