Extracellular Vesicles in Cancer Immunotherapy

Extracellular vesicles (EVs) are nanoscale vesicles that contain a repertoire of molecules representing the cell of origin. Cancer cell-derived EVs are enriched in cancer-associated antigens. Therefore, these EVs may have applications in cancer immunotherapy, e.g., as components of cancer vaccines to trigger antitumor T-cell activity. Similarly, dendritic cell-derived EVs may also be attractive cancer vaccine candidates because they expose complexes of major histocompatibility complex class I and II molecules loaded with tumor antigens as well as the costimulatory molecules CD80 and CD86, which are essential for the induction of antitumor T-cell immune responses. Cell-free EV-based vaccines have several advantages over classical cell-based vaccines, particularly in terms of no requirement of preserving “viability” and serum stability. However, there are still several challenges to the successful application of EV-based cancer vaccination in the clinical setting. For example, the well-known immunosuppressive characteristics of cancer cell-derived EVs may counteract their antitumor effects. In this chapter, we highlight the potential applications of EVs in cancer immunotherapy, particularly in the field of cancer vaccination.