Figure 7. A schematic model of the role of tumor-derived extracellular vesicle (TEV) and CD300a in tumor immunity.

RNA-containing TEV is incorporated into the endosomes in dendritic cells (DCs), where phosphatidylserine (PS) on TEV binds to CD300a and inhibits the TLR3–TRIF–IRF3 signaling pathway initiated by TEV-derived RNA binding to TLR3, resulting in the decrease in interferon-β (IFN-β) production by DCs and the number of tumor-infiltrating Treg cells. The Treg cells regulate tumor development.