Stanford team identifies explosive immune cells in flatworms that self-destruct to kill microbes

Stanford scientists have uncovered a previously unknown immune cell in planarian flatworms that self-destructs explosively, a phenomenon they term ruptosis. Triggered by elevated activin levels, the ruptoblasts burst open in five minutes, releasing compounds that kill nearby bacteria and mammalian cells while the cell itself disappears. Experiments showed the cells effectively eliminated E. coli, human kidney cells and mouse blood cells, with damage confined to the immediate vicinity.

The researchers note that flatworms' remarkable regenerative capacity allows them to tolerate such localized destruction, a feature absent in vertebrates. They propose that understanding this rapid, localized attack could guide the development of targeted treatments for bacterial infections and cancer. The findings highlight the value of studying unconventional model organisms to reveal immune strategies not present in humans.