Scientists at Stanford University and Ben-Gurion University have discovered a previously unknown type of immune cell in flatworms that kills invading bacteria by exploding — a process the researchers have named "ruptosis."
The cells, dubbed "ruptoblasts," detonate within roughly five minutes of activation and then disappear completely, according to findings published by the team. The blast, triggered by the hormone activin, kills nearby bacteria and affects roughly 70 surrounding cells within its radius. In laboratory tests, the mechanism effectively killed E. coli bacteria and was shown to interact with human kidney cells and mouse blood cells, suggesting the underlying biology may not be unique to flatworms.
The findings, published in the journal Cell in June and drawing renewed attention this week, add a new entry to the relatively short list of known immune-cell types across the animal kingdom. Researchers say the self-destructing defense mechanism could eventually inform targeted treatments for infections or cancer, since a cell type that reliably detonates on command and clears itself afterward could, in principle, be harnessed or mimicked in engineered therapies.
Much of the excitement around the discovery stems from how basic it is: flatworms are simple, ancient organisms often used to study regeneration and fundamental biology, and finding an entirely new class of immune cell in such a well-studied model organism suggests there may be more undiscovered immune mechanisms waiting to be found even in extensively researched species. Follow-up research is expected to explore whether related self-destructing immune cells exist in other invertebrates, and whether the activin-triggered pathway that controls ruptosis in flatworms has any functional parallel in more complex animals.