Interleukin-2 Surface Displayed M1 Macrophage-Derived Extracellular Vesicles for Modulating the Tumor Microenvironment

Purpose: Cancer Immunotherapy aims to enhance the immune system's ability to recognize and eliminate Cancer cells, providing a sustained and effective immune response. However, the tumor microenvironment (TME), characterized by an abundance of tumor-associated M2 macrophages and the presence of exhausted or naïve T cells (non-effector T cells), remains a major barrier to effective immunotherapy. Herein, inflammatory M1 macrophage-derived extracellular vesicles (M1EV) were surface-modified to display interleukin-2 (M1EV_IL2), aiming to develop a multifunctional Cancer immunotherapeutic agent capable of modulating both innate and adaptive immune responses.

Methods: We engineered M1EV to label the surface with azide groups through metabolic glycoengineering and developed M1EV_IL2 that displayed IL-2 via bioorthogonal chemistry. M1EV_IL2 were purified by size-exclusion chromatography (SEC) and characterized through comprehensive analyses, including nanoparticle tracking analysis (NTA). In vitro macrophage repolarization and T cell activation were evaluated at the gene-expression level, followed by ex vivo assays assessing T-cell proliferation, cytokine secretion, and activation marker expression.

Results: M1EV_IL2 effectively retained the intrinsic physicochemical properties of EVs while displaying IL-2 stably on its surface. It upregulated M1 macrophage markers, IL-1β and CXCL10, while downregulating the M2 macrophage marker CD206, thereby inducing M2-to-M1 macrophage repolarization. In addition, M1EV_IL2 also activated CD4⁺ T cells and induced the activation of naïve CD8⁺ T cells to effector T cells, leading to enhanced cell proliferation and secretion of antitumor cytokines.

Conclusion: These results indicate that M1EV_IL2 has the potential to reshape the tumor immune landscape by simultaneously activating macrophages and T cells, thereby enhancing both innate and adaptive immune responses. Unlike conventional Cancer therapies, which directly target tumor cells, M1EV_IL2 is expected to enhance immune responses, potentially mitigating adverse effects while improving therapeutic efficacy.

T cell activation; cancer immunotherapy; extracellular vesicles; interleukin-2; macrophage repolarization.