Movie 1

Antigen is transported in vesicles positive for early and late endosomal markers. A20 D1.3 cells were transfected with GFP-Rab5 (right panel), loaded with LysoTracker (left panel) and activated with RRx-αIgM (middle panel). Live-imaging was performed with SDCM (sCMOS Orca Flash4 v2 camera) on a single plane. Triple-positive vesicles are highlighted with a purple circle tracking the spots in the antigen channel. Movie was recorded 10 min after activation and imaged every 2 s.