LL-37 induces the release of neutrophil-chemotatic factors from airway epithelial cells during infection with <i>P</i>. <i>aeruginosa</i>.

A) Representative examples of neutrophil migration assayed in ChemoTx chambers. Human neutrophils were assayed migrating towards chambers containing filtered conditioned supernatant from NHBE cells treated for 3 hours with media only (untreated control), 20 μg/ml LL-37, 20 μg/ml ScrLL-37, PAO1 at 10:1 MOI, PAO1 + LL-37 or PAO1 + ScrLL-37. Migrated cells were stained with 1 μM Calcein AM for 15 minutes at 37˚C, and imaged by microscopy. B) Quantitation of migrating neutrophils shown in A, expressed as fold change compared to untreated control. Data represent means +/- SEM from n = 3–6 separate experiments performed with neutrophils isolated from a different donor for each experiment, *** p < 0.001, ** p<0.01, * p < 0.05 versus PAO1 + LL-37 condition, by 2-way ANOVAs with Bonferroni Post-test, to examine the effect of PAO1 infection, with or without LL-37, or scrLL-37 treatment. ns = no significant difference.