Contact of target NB4 and APL cells with HUVECs. Two-fold target NB4 or APL cells were added to HUVECs at 37°C for various times before the mixed cells were imaged. (A) Confocal image of free (arrowhead) and bound (arrows) CMFDA-labeled target NB4 cells (green) to the membrane of a CMTPX-stained EC (red) after 30 minutes of incubation. (B) After 1-hour coculture, attached target APL cell (left; star; scanning electron microscopy) and target APL cell with apoptotic bodies (right; square; transmission electron microscopy) to the surface of ECs (triangles). (C) A target NB4 cell with apoptotic bodies (left; square; transmission electron microscopy) and a target APL cell (right; star; scanning electron microscopy) trapped by ECs (triangles) after 1.5 hours of incubation. (D) Transmission microscopic image of several separated apoptotic bodies of APL cells (square) in an EC (triangle) and another target APL cell with apoptotic bodies (star) bound to this EC after 2-hour incubation. (E-F) Transmission micrographs showed target APL cells (stars) undergoing degradation in ECs (triangles) after 3 hours. Scale bars represent 10 μm (A) or 4 μm (B-F).