ARG1 and neoplasm: Consistent with the results obtained in vivo with the EVs-ARG1 in the adoptive transfer model in non-tumor settings, ID8-ARG1 bearing-mice had a significantly reduced percentage of activated CD69-positive CD4+ (Fig. 7b left) and CD8+ (Fig. 7b middle) T-cells in the peritoneal cavity relative to mice bearing control tumor cells.