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In the early 2000s, Arturo Zychlinsky at the Max Planck Institute for Infection Biology in Berlin found that mammalian immune cells called neutrophils use an enzyme called neutrophil elastase (NE) to cleave bacterial virulence factors. When Zychlinsky and his colleagues delved deeper into this defense mechanism, they realized that when activated by bacteria, human neutrophils release NE in what, under the microscope, looked like a fibrous structure. This structure turned out to be a meshwork of NE, other proteins, and copious amounts of DNA. In cultured human neutrophils, the webs were able to trap the bacteria that had triggered their formation, thereby limiting infection, so Zychlinsky and colleagues dubbed them neutrophil extracellular traps, or NETs.
The fact that neutrophils used their nuclear material to catch pathogens was intriguing to immunologists and cell biologists alike. The work of the Zychlinsky lab suggested that the release of ...