Scientists Reprogram Immune System’s ‘cleanup Crew’ to Target Cancer and Autoimmune Diseases
A groundbreaking new approach to precision medicine harnesses the body’s natural cellular disposal system to eliminate harmful cells, offering a potential alternative to complex immunotherapies like CAR-T cell therapy. Published November 25, 2025, in Nature Bioengineering, research from Kyoto University in Japan details the triumphant repurposing of phagocytes – immune cells that engulf and remove debris – to target and destroy cells involved in cancer and autoimmune disorders.
The human body constantly clears out dead and damaged cells through a process involving phagocytes, specialized immune cells that act as a natural “cleanup crew.” When a cell is slated for removal,it displays a molecule called phosphatidylserine on its surface,essentially tagging itself for disposal. A blood protein known as Protein S then binds to this tag and together attaches to receptors on phagocytes, initiating the engulfment process, or phagocytosis.
Researchers have now engineered a way to hijack this natural system, directing it to target living cells that pose a threat to the body. “What we’ve done is take that natural cleaning system and reprogram it to target living cells that shouldn’t be there,” explained a senior researcher involved in the study.
The team developed a modified version of Protein S, dubbed “Crunch,” which retains the ability to bind to phagocytes but has been altered to recognize specific markers on targeted cells. “We built Crunch by modifying protein S, which normally helps phagocytes recognize dead cells. But rather of binding to dead cells, we gave Crunch the ability to recognize specific living cells we want to remove, like cancer cells or overactive immune cells in autoimmune diseases,” the researcher elaborated.
Crunch was created by replacing the protein’s usual binding site for dead-cell lipids with a customizable component capable of recognizing unique surface markers on targeted cells.In laboratory tests using mice, Crunch successfully eliminated cancer cells engineered to express a specific surface protein, allowing researchers to track its effectiveness.
Furthermore, the team demonstrated Crunch’s potential in treating autoimmune diseases. “We also used it to eliminate certain immune cells in a model of lupus, a disease where the immune system attacks healthy tissue. In both cases, the harmful cells were successfully cleared, and signs of disease were reduced,” stated the study’s lead investigator.
This marks the first time the body’s innate cleanup system has been intentionally repurposed as a therapeutic tool. The success of Crunch in animal models suggests a promising new avenue for precision therapeutics,potentially overcoming the limitations of current immunotherapies that require extensive manipulation of a patient’s own immune cells.
Unlike CAR-T cell therapy, which involves collecting, modifying, and reinfusing a patient’s immune cells, Crunch, as a protein-based treatment, could be administered via a simple injection.”We think this could become a new kind of therapy that can be adapted to many conditions,” the lead investigator noted. “We can also adopt the targeting sensors from antibodies and CAR-T. It’s the ecosystem for the various therapeutic tools.”
This research, originating from Kyoto University and detailed in Nature Bioengineering, represents a significant step toward a more streamlined and adaptable approach to treating a wide range of diseases.
Source: Kyoto University ; Image: Shutterstock
– Crunch, the modified Protein S, offers a potential advantage over CAR-T cell therapy due to its simpler governance method-a simple injection versus cell collection and reinfusion.
– This research focuses on repurposing the body’s existing systems. How does this differ from customary drug development? This approach aims to harness natural processes,potentially reducing side effects and increasing effectiveness.
This article can be found at Phagocytic clearance of targeted cells with a synthetic ligand.
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