LIPOPOLYSACCHARIDE IS PRESENT IN IMMUNE-COMPLEXES ISOLATED FROM SPUTUM IN PATIENTS WITH CYSTIC-FIBROSIS AND CHRONIC PSEUDOMONAS-AERUGINOSA LUNG INFECTION

Sputum samples from seven patients with cystic fibrosis and chronic P. aeruginosa lung infection were investigated for immune complexes by P EG precipitation and in two different complement binding assays. All s even patients were immune complex positive. The components involved in immune complex formation were identified by SDS-PAGE and immunoblotti ng. We found P aeruginosa lipopolysaccharide as a major antigen. Both core and O-specific saccharide antigens could be demonstrated. IgG and IgA were the immunoglobulins involved, with IgG2 as the dominating Ig G subclass. Lipopolysaccharide has a number of biological activities a nd its presence in sputum may have consequences for the pathogenesis o f lung disease in cystic fibrosis.