Cellular Internalization of Exosomes Occurs Through Phagocytosis

Exosomes play important roles in many physiological and pathological processes. However, the exosome-cell interaction mode and the intracellular trafficking pathway of exosomes in their recipient cells remain unclear. Here, we report that exosomes derived from K562 or MT4 cells are internalized more efficiently by phagocytes than by non-phagocytic cells. Most exosomes were observed attached to the plasma membrane of non-phagocytic cells, while in phagocytic cells these exosomes were found to enter via phagocytosis. Specifically, they moved to phagosomes together with phagocytic polystyrene carboxylate-modified latex beads (biospheres) and were further sorted into phagolysosomes. Moreover, exosome…