Abstract: Exosomes are endosome-derived vesicles (40-100 nm) formed during the formation of multi-vesicular bodies (MVBs),which contains plasma membrane,membrane protein and functional signaling protein.The variety of proteins depends on the origin of EXO and thus imparts distinct biological function.Exosomes derived from antigen-presenting cells (APC),such as dendritic cells,and tumor cells may play an important role in immunological regulation and cancer immunotherapy.The present review summarizes the recent studies of EXO-related biological function.