Fibronectin-Cleaving Activity in Bronchial Secretions of Patients with Cystic Fibrosis

In cystic fibrosis, colonization of the airways with Pseudomonas aeruginosa follows colonization with Staphylococcus aureus and is related to accelerated deterioration of pulmonary function. Because P. aeruginosa adheres better to cell surfaces devoid of fibronectin, we searched for fibronectin-cleaving activity in bronchial secretions and saliva from 24 patients with cystic fibrosis who were followed up for 4.5 y and from two control groups. Proteolytic activity against 125I-labeled fibronectin wascontinuously present in cystic fibrosis bronchial secretions; significantly higher fibronectin-cleaving activity was found in older vs. younger patients, in patients with advanced disease stages determined by a five-stage scoring system, and in those colonized with P. aeruginosa. The fibronectin-cleaving activity was due to neutrophil elastase and cathepsin G. Cystic fibrosis bronchial secretions had proteolytic activity against surface fibronectin of airway mucosal cells. Thus fibronectin-cleaving activity of bronchial secretions rather than of saliva may favor P. aeruginosa colonization of the upper respiratory tract in individuals with cystic fibrosi

Eukaryote ribosomes possess a binding site for concanavalin A.

Ribosomes prepared from chicken liver or rabbit reticulocytes bound concanavalin A in a molar ratio of approximately 1:1. This binding is to the large subunit of the eukaryote ribosomes with a dissociation constant of 5 X 10(-7) M (0 degrees). The binding of concanavalin A to Escherichia coli ribosomes was much less. Binding to the RNA or to possible membrane contaminants was ruled out in control experiments. Chicken liver ribosomes were labeled in vivo with 3H-labeled amino acids, purified, and dissociated in sodium dodecyl sulfate. Affinity chromatography of this preparation made it possible to isolate the small proportion of the ribosomal proteins (about 1.5%) containing the concanavalin A binding site. This protein moved as a single band during electrophoresis on polyacrylamide gels containing sodium dodecyl sulfate and showed an apparent molecular weight of 31,000

Fibronectin-Cleaving Activity in Bronchial Secretions of Patients with Cystic Fibrosis

In cystic fibrosis, colonization of the airways with Pseudomonas aeruginosa follows colonization with Staphylococcus aureus and is related to accelerated deterioration of pulmonary function. Because P. aeruginosa adheres better to cell surfaces devoid of fibronectin, we searched for fibronectin-cleaving activity in bronchial secretions and saliva from 24 patients with cystic fibrosis who were followed up for 4.5 y and from two control groups. Proteolytic activity against 125I-labeled fibronectin wascontinuously present in cystic fibrosis bronchial secretions; significantly higher fibronectin-cleaving activity was found in older vs. younger patients, in patients with advanced disease stages determined by a five-stage scoring system, and in those colonized with P. aeruginosa. The fibronectin-cleaving activity was due to neutrophil elastase and cathepsin G. Cystic fibrosis bronchial secretions had proteolytic activity against surface fibronectin of airway mucosal cells. Thus fibronectin-cleaving activity of bronchial secretions rather than of saliva may favor P. aeruginosa colonization of the upper respiratory tract in individuals with cystic fibrosis