近年来，多项研究表明外排体（ Exosome）是从细胞上产生的鳞片状脱落的囊泡，具有胞外酶的活性。最初认为它仅仅起到一种“垃圾袋”的作用，允许细胞丢掉不需要的蛋白。当内涵体和细胞膜相互融合并且释放 Exosome进入细胞间隔。这些囊泡体从细胞内释放出来，它们就被认为是Exosome。现证实它来源于细胞后期内涵体，并且可以在造血干细胞和上皮细胞的培养基中检测到。Exosome具有多种生物学功能，它可以使得细胞在不需要直接接触下完成细胞间生物信号转导，其在细胞保护、免疫、疾病诊断等方面成为目前研究的热点。“,”In recent years,several studies have shown that exosome is vesicle shed from the cell with the extracellular enzyme activity.It was initially believed to play a “garbage bags”effect,allowing the cells to lose unwanted proteins.When endosomes and the cell membrane merge and release vesicles into the cell interval.These vesicles released from the cells are considered exosome.Now it is confirmed to have derived from late endosomes,and can be detected in hematopoietic stem cells and epithelial cells in culture medium . Exosome has a variety of biological functions, it can make the cell to complete the biological signal transduc-tion between cells without direct contact,and it has become a hot research in cell protection,immunization, and disease diagnosis.