Breakthrough in NK Cell Expansion: Novel K562 Feeder Line Enhances Yield and Purity

A new study published in BMC Biotechnology introduces an innovative engineered K562 feeder cell line (K562-4-1BBL-mbIL-21/IL-15) that has demonstrated remarkable performance in NK cell expansion. Researchers reported that when peripheral blood mononuclear cells (PBMCs) were co-cultured with this novel feeder line, NK cells achieved a median 17,902-fold expansion within 14 days, with final purity exceeding 90%.

Importantly, the expanded NK cells maintained strong functional characteristics, including robust cytotoxic activity against tumor cells in vitro. This represents a significant advancement in the development of NK cell–based immunotherapies, where both scalability and functional integrity of the expanded cells are essential for clinical application.

Industry Significance

The ability to reliably expand NK cells at high purity and scale is a major hurdle for the cell therapy field. Traditional feeder systems, while effective, often face limitations in yield, consistency, and regulatory acceptance. The development of engineered feeder cells that incorporate co-stimulatory molecules (4-1BBL) and membrane-bound cytokines (IL-21 and IL-15) demonstrates how rational design can overcome these barriers.

This progress has critical implications for off-the-shelf NK cell therapies, which are increasingly viewed as a complementary or alternative approach to CAR-T therapies due to their lower risk of graft-versus-host disease and potential for broader applicability.

Outlook

As NK cell-based therapies continue to gain traction, advances in feeder cell technology will be key to unlocking their clinical and commercial potential. By combining strong expansion efficiency with functional potency, feeder systems such as the novel K562-4-1BBL-mbIL-21/IL-15 line pave the way for more accessible, effective, and scalable NK cell therapies.

Hillgene's Contribution

At Hillgene, we have developed our own Genetically Modified K562 Feeder Cells , designed to enable rapid and efficient NK cell expansion. Compared to conventional cytokine-based culture methods, our product can achieve the same fold expansion at one-tenth of the cost, offering a practical and scalable solution for both research and clinical applications. → Start with Genetically Modified K562 Feeder Cell

Source: BMC Biotechnology - “A novel feeder cell based on 4-1BBL and membrane-bound IL-21/IL-15 induce highly expansion and anti-tumor effect of natural killer cells” (August 27, 2025).