Antibody‐Targeted Artificial T Cell and Natural Killer Cell Derived Vesicles for Cancer Immunotherapy

T cell and NK92 cell‐derived extracellular vesicles or artificial cell‐derived vesicles (ACDVs) exhibit anti‐cancer effects through inherited cytotoxic proteins like perforin and granzyme or transmembrane receptors like FasL and TRAIL. The anti‐cancer potential of artificial T and NK vesicles has been improved by attaching targeting moieties to their surface using genetic engineering or covalent surface modifications. However, the genetic engineering of immune cells from which the vesicles are derived is laborious, expensive, and inefficient, and naturally derived exosomes are released in low quantities. Here, we compared the properties of tumour‐targeted and untargeted ACDVs from activated‐T cells and NK92 cells.

We examined whether the cancer cell‐killing capacity of ACDVs derived from activated‐T and NK92 cells could be targeted to cancer cells by conjugating tumour‐targeting antibodies to their surface. We targeted T and NK92 ACDVs to cancer cells possessing the xenoantigen, N‐glycolyl neuraminic acid GM3 ganglioside, using the 14f7hT antibody or the tumour antigen, epidermal growth factor receptor, using the nimotuzumab antibody. Antibody targeting improved the cell interaction, internalization, and cytotoxicity of T and NK92 ACDVs. Interestingly, the T‐ACDVs retained perforin, granzyme, FasL and TRAIL, whereas NK92 ACDVs retained perforin, granzyme and FasL. Based on their ease of production and lower cost, we chose NK92 ACDVs for in vivo and ex vivo studies. Intravenously injected nimotuzumab‐conjugated NK92 ACDVs decreased the tumour volumes of EGFR‐expressing ovarian cancer xenografts in mice. 14F7hT‐conjugated NK92 ACDVs showed cytotoxic activity against chronic lymphocytic leukaemia biopsies.

This research shows the potential for using antibody‐conjugated, cytotoxic T and NK ACDVs as a feasible and effective approach for tumour‐targeted immunotherapy.