A web of DNA flung at pathogens
Neutrophils are among the first responders to infection, and beyond engulfing microbes they can deploy neutrophil extracellular traps (NETs). A NET is a web of decondensed DNA studded with histones and antimicrobial proteins from the neutrophil's granules. Extruded into the surrounding space, it physically ensnares bacteria and fungi and concentrates toxic proteins on them.
The process, often called NETosis, can involve the death of the neutrophil that releases the trap, though some NET release occurs without cell death. The enzyme peptidylarginine deiminase 4 (PAD4) helps unwind the chromatin that becomes the web.
When a useful weapon turns harmful
NETs help contain infection, but they are double-edged. Excess or poorly cleared NETs expose self-DNA and histones in tissue and have been linked in research to autoimmune conditions such as lupus, to clot formation in blood vessels, and to organ injury in severe systemic illness.
How tightly NET formation should be encouraged or restrained therapeutically is an open research question. This is general educational information about immunology, not medical advice.