Engineered Immunomodulatory Extracellular Vesicles from Epithelial Cells with the Capacity for Stimulation of Innate...

Extracellular vesicles (EVs) are generated in all cells. Systemic administration of allogenic EVs derived from epithelial and mesenchymal cells has been shown to be safe, despite carrying an array of functional molecules, including thousands of proteins. To address whether epithelial cell-derived EVs can be modified to acquire the capacity to induce an immune response, we engineered 293T EVs to harbor the immunomodulatory molecules CD80, OX40L, and PD-L1. We demonstrated abundant levels of these proteins in the engineered cells and EVs. Functionally, the engineered EVs efficiently elicited positive and negative costimulation of human and murine T cells. In the setting of cancer and autoimmune hepatitis, the engineered EVs modulated T cell functions and altered disease progression. OX40L EVs also provided enhanced antitumor activity in combination with anti-CTLA-4 in melanoma-bearing mice. In addition, we added multiple immunomodulatory proteins in EVs (EV^mIM), attempting to elicit an immune response in both lymphoid and myeloid compartments. The EV^mIM containing CD80, 4-1BBL, CD40L, CD2, and CD32 engaged both T cells and antigen presenting cells (APCs) in melanoma tumors, demonstrating the capacity for EV^mIM to elicit antitumor activity. Our work provides evidence that EVs can be engineered to induce specific immune responses with translational potential to modulate immune cell functions in pathological settings.