Modifications of plasma fibronectin in cystic fibrosis patients.

Recurrent pulmonary infections with Staphylococcus aureus and Pseudomonas aeruginosa are a major problem in cystic fibrosis (CF), leading to severe and progressive deterioration of the respiratory tract. Fibronectin (FN) has a binding site(s) for S. aureus and Streptococcus pyogenes. This bacterial bindings site(s) was studied by using FN from patients with CF and comparing them with FN purified from the plasma of bronchitis and normal subjects by an enzyme-linked immunosorbent assay technique. We found a decreased binding of the CF FN to these bacteria in all seven CF patients. Other differences between the CF FN and normal FN were a marked modification in the pattern of peptide migration in polyacrylamide gel electrophoresis after hydrolysis with various proteinases and an increase or decrease of the total sugar content of the FN.