Extracellular vesicles released by ovarian carcinoma contain arginase 1 that mitigates antitumor immune response.

Expression of arginase-1 (ARG1) is an immunosuppressive feature of tumor microenvironment that leads to depletion of ʟ-arginine, a nutrient required for T-cells expansion. Ovarian carcinoma cells release extracellular vesicles carrying enzymatically active ARG1, that contributes to local and systemic immune suppression, which can be restored by ARG inhibitor.