Proteomic analysis of human T cell-derived exosomes reveals differential RAS/MAPK signaling.

Exosomes are cell-derived vesicles that have been implicated in the pathogenesis of many inflammatory diseases. More specifically, it has been shown that T cell-derived exosomes can induce immunological responses; however, little is known about the mechanism and the molecular content of these vesicles. Here, we used a proteomic approach to characterize human T cell-derived exosomes. We found that specific proteins of the RAS signaling pathway were enriched in exosomes derived from activated T cells, and that these vesicles induced ERK phosphorylation in recipient immune cells. Our findings support a mechanistic role of exosomes in cellular activation, and further studies should consider exosomes as a biomarker for inflammatory diseases.