255 A Bacterial Serine Protease Inhibitor, Ecotin Inhibits Neutrophil Elastase in Cystic Fibrosis Airway Samples

Abstract

OBJECTIVES/GOALS: Ecotin is a potent periplasmic serin protease inhibitor that was first described in Escherichia coli (E. coli). Ecotin is known to inhibit a broad range of serine proteases including NE. Therefore, we hypothesized that ecotin can inhibit the NE activity present in CF clinical sputum samples. METHODS/STUDY POPULATION: To investigate the function of ecotin on CF sputum, orthologues from Campylobacter rectus and Campylobacter showae were recombinantly expressed and purified from E. coli to generate C. rectus ecotin, C. showae ecotin, and E. coli ecotin. Ecotin was added to CF sputum supernatant samples at various concentrations and NE enzymatic activity was measured by a fluorometric assay kit. In addition, CF sputum and healthy sputum was added to PMNs isolated from healthy donors for 3.5 hours and NE was measured with immunofluorescence staining. The sputum was washed two times prior to measuring NE released and on the PMNs, and PBMCs was used as a control. RESULTS/ANTICIPATED RESULTS: Our results indicate a clear inhibition of NE activity in CF sputum supernatant. C. showae ecotin showed the greatest inhibitory effect on NE activity in CF sputum supernatant. We also saw that CF sputum supernatant causing healthy PMNs to release more NE suggesting that NE in the CF airway may trigger more NE release from newly incoming PMNs to the lung. Our next steps will be to determine if ecotin can inhibit NE on the PMN surface and released from PMNs. DISCUSSION/SIGNIFICANCE: Neutrophil elastases are produced by PMNs to kill microbial pathogens in the lung, however in CF, the pathogens are unable to be killed by NE and instead causes severe lung damage. PMNs and NE has been shown to be elevated in the sputum of CF patients and there is currently no NE therapeutic inhibitor that has been effective in these patients.