Progress in research on role of exosomes in tumor immunity

Exosomes are small membrane vesicles formed by multivesicular body of many cells. Their function was considered as only degrading endocytic substances at first. However, the study during the past several years has proved that the specific function of exosomes are closely associated with the cells from which they are derived. Exosomes carry several unique proteins, such as adhesion protein and heat-shock protein, and play important roles in signal transduction. Since exosomes can deliver antigen to T cells, they are also important to immune system. As a novel tool for immune therapy, exosomes may be used for the treatment of tumors and immune tolerance. The mechanisms of exosomes in induction of anti-tumor immune response and immune suppression are reviewed in this paper.