Neutrophil extracellular traps (NETs) are tangles of DNA impregnated with proteolytic molecules and are released ('NETosis') by neutrophils as these cells die in response to bacterial or fungal infection. In Nature Medicine, Kubes and colleagues investigate 'NETosis' in vivo and its contribution to the control of infection. Intravital microscopy of skin shows rapid (<2 hours) NETosis specifically in response to bacterial challenge but not in response to sterile inflammation. NETosis occurs only in tissue parenchyma but not in the vasculature, presumably to limit widespread and potentially pathogenic dissemination of NETs. Furthermore, signaling via Toll-like receptor 2 and complement receptors is required for NETosis, although specific stimulation of either of these pathways is not sufficient to trigger NETosis. Interestingly, neutrophils undergoing NETosis continue chemotaxis and phagocytosis, a previously unappreciated degree of multitasking for 'NETosing' cells. Finally, inhibiting NET formation in vivo exacerbates bacteremia, which demonstrates the importance of this process to microbial control.

Nat. Med. 18, 1386–1393 (2012)