Figure 2. Non-oxidative PMN pathways promote mucoid conversion.

The mucoid conversion frequency was determined upon treatment of PAO1algD-cat with PMN lysates or granule preparations (A), sub-inhibitory concentrations (0.25 µM) of LL-37, human beta defensin 1 and 2 (hBD1/2) and human neutrophil peptide 1 (HNP1) (B), or sputum isolated from CF patients (C). In C, sputum was immune-depleted with a monoclonal LL-37 antibody or mouse IgG₁ isotype control antibody. All experiments were performed in triplicate on four independent occasions. Values are mean +/− SEM. Statistical analysis was carried out comparing HBSS or 10 mM sodium phosphate buffer (pH 6.2) (SPB) to PMN component treated in A and B and anti-LL-37 to isotype control treated sputum in C, using an unpaired two-tailed Mann-Whitney test (* p≤0.05, **p≤0.001).