Natural killer cell-derived extracellular vesicle significantly enhanced adoptive T cell therapy against solid tumors via versatilely immunomodulatory coordination

Insufficient tumor tropism, MHC class I molecules (MHC-I) defects of tumor cells, and immunosuppressive tumor micro-environment (TME) seriously imperil the efficacy of adoptive T cell therapy on solid tumors. Here, natural killer cell-derived extracellular vesicle (Nev) is used as a versatile toolkit to synergistically improve adoptive T cell therapy for solid tumors. Specifically, Nev is modified with dibenzocyclooctynes (DBCO) linked with pH-sensitive benzoic-imine bonds; meanwhile, cytotoxic T lymphocyte (CTL) is decorated with azide groups. Then CTL is armed with Nev (CTL-Nev) through the click chemistry reaction. After systematic administration, Nev obviously promotes the tumor-targeting accumulation of CTL coming from its native tumor-tropism capability. Then, the cleavage of benzoic-imine bonds in the slightly acidic TME leads to the release of Nev, which not only directly induces tumor apoptosis but also promotes the action of CTL via multiplex pathways, such as up-regulating the MHC-I expression on tumor cells, reprogramming tumor-associated macrophages from pro-tumoral M2 phenotypes to tumoricidal M1 phenotypes. The all-around coordination of Nev with CTL results in potent tumor repression. [Figure not available: see fulltext.].