Lipopolysaccharide antigens produced by Pseudomonas aeruginosa from cystic fibrosis lung infection

Abstract The lipopolysaccharides (LPS) produced by 10 Pseudomonas aeruginosa isolates from cystic fibrosis (CF) lung infection were investigated using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) techniques. The silverstained SDS-polyacrylamide gel of proteinase K digested whole-cell lysates from these isolates showed great variation in the number of repeat units in the O polysaccharide and also in the amounts of O polysaccharide produced. LPS was extracted from the sputum of a CF patient. The SDS-PAGE profile obtained from in vivo-grown bacteria showed a ladder-like pattern similar to that obtained for LPS extracted from early stationary phase cells of the same isolate grown in vitro in iron-depleted chemically defined media, indicating that an O polysaccharide was produced during growth in the CF lung. Results of ELISA titrations indicated that the patient's serum, but not sputum, contained high titres of IgG to P .