Regulatory effects of stem cell-derived extracellular vesicles on T-lymphocytes

Extracellular vesicles (EVs) are subcellular component secreted by paracellular mechanism, which are essentially a group of nanoparticles. They are bilayer membrane bound vesicles containing proteins, nucleic acids and other active components. EVs gain significant status by the transfer of signal molecules among cells. Recent studies on the regulatory effects of EVs on T cells both in vitro and in vivo have aroused extensive interest. In most investigations, stem cells have been reported to suppress the proliferation, activation and differentiation of T cells, meanwhile, stem cells also have been found to enhance the immune response of T cells in few reports. Virtually all cell types have the ability to release EVs including stem/progenitor cells. EVs are recognized as a novel mechanism of intercellular communication, with immunoregulatory effects similar to those of parental cells such as stem/progenitor cells. The aim of this review is to summarize the possible mechanisms underlying the regulatory effects of stem/progenitor cell-derived EVs on T cells. Key words: Stem cell; Extracellular vesicle; T cell; Immune regulation