iPSC-derived feeder platforms potentiate natural killer cell Immunotherapy

Natural killer (NK) cells are attractive effectors for cancer immunotherapy, yet their clinical translation is limited by inefficient expansion, short persistence, and reliance on tumor-derived feeder systems. Here, we establish a hybrid differentiation strategy to generate highly pure NK cells from human induced pluripotent stem cells (iPSCs) via an intermediate hematopoietic progenitor (iHPC) stage and develop iPSC-derived feeder platforms to support NK survival and function. Engineered iHPCs expressing the co-stimulatory molecule CD86 and membrane-bound interleukin-21 (mbIL-21) effectively prolonged the survival of primary NK cells and promoted activation-associated clustering in vitro. Although iPSC-derived NK cells exhibited an immature phenotype, genetic introduction of stimulatory molecules, with predominant expression of CD86, enhanced activation marker expression and cytotoxic activity despite limited surface expression of mbIL-21 and 4-1BBL. These findings identify iPSC-derived hematopoietic progenitors as a tumor-free feeder alternative and demonstrate that implementation of a self-feeder strategy can potentiate NK cell function. Together, this work advances scalable and clinically adaptable approaches for NK cell manufacturing.