Engineered Immunomodulatory Extracellular Vesicles from Epithelial Cells with the Capacity for Stimulation of Innate and Adaptive Immunity in Cancer and Autoimmunity

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 (EVmIM), attempting to elicit an immune response in both lymphoid and myeloid
compartments. The EVmIM containing CD80, 4-1BBL, CD40L,
CD2, and CD32 engaged both T cells and antigen presenting cells (APCs)
in melanoma tumors, demonstrating the capacity for EVmIM 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.