NETosis by neutrophils is characterized by the extrusion of genomic DNA embedded with antimicrobial factors in response to bacterial or fungal infection. In PLoS Pathogens, Rada and colleagues investigate the mechanisms by which the opportunistic pathogen Pseudomonas aeruginosa triggers NETosis. Flagellated P. aeruginosa can elicit NETosis, but non-flagellated P. aeruginosa cannot. However, NETosis is not dependent on the known flagellin receptors TLR5 or NLRC4, nor is the monomeric purified form of flagellin able to trigger NETosis. Instead, what seems to be critical is the motility of flagella, because non-motile mutant bacteria that have otherwise normal flagella cannot trigger NETosis. Flagellar motility is therefore an additional parameter sensed by the immune system and used to 'tune' the extent of the neutrophil response.

PLoS Pathog. (17 November 2016) http://dx.doi.org/10.1371/journal.ppat.1005987