Engineered Generation of Human Natural Killer Cells From Different Somatic Cells Subjected to Physical Reprogramming

Abstract Background: As part of the innate immune system, natural killer (NK) cells can directly kill virus-infected cells and malignant cells without pre-immunization. NK cell-based immunotherapy has attracted tremendous attention as a practical treatment for cancer and other diseases. In order to provide unlimited “off-the-shelf” NK cells to serve many recipients, we designed and demonstrated an overall manufacturing scheme for mass production of NK cells from physically reprogrammed somatic cells. Methods: Different somatic cells would be reprogrammed into induced pluripotent stem cells (iPSCs) by physical-dynamic suspension culture system, which was non-viral, non-integrated, non-compound-induced, feeder-free, and serum-free. The pluripotency of iPSCs was assessed by immunofluorescence, flow cytometry analysis, western blot, and teratoma assay. By using a combination of cytokines, iPSCs would be further differentiated into NK cells. Immunofluorescence, flow cytometry analysis, and lactate dehydrogenase (LDH) release method were performed to evaluate the characteristics of NK cells. Results: Starting from human somatic cells, we obtained iPSCs in the form of spherical embryoids (SEs) through physical reprogramming. iPSCs were similar to embryonic stem cells (ESCs) in their characteristics, including morphology, expression of pluripotency-associated markers, and teratoma formation. NK cells were efficiently generated from SEs by a combination of cytokines under feeder-free conditions. SEs-NK cells share similar phenotypic and functional characteristics with human NK cells, including morphology, cell surface markers, and cytotoxicity. Conclusions: We have not only established a practical approach for large-scale production of universal NK cells, but also provided a platform for generating good manufacturing practice (GMP)-compliant iPSCs through physical dynamics, thus suggesting that the physical reprogramming will become a more promising strategy for future biotherapies.