700 CYSTIC FIBROSIS (CF) FACTOR – AN ABNORMAL SERUM GLY- COPEFTIDE

Abstract

A CF-specific peptide affecting the rhythmic beat of cilia from rabbit tracheal explants and oyster gills has previously been partially purified and characterized. In the present study, a glycopeptide (molecular weight about 6000) was purified to homogeneity from sera of controls and CF patients. Both the CF and control glycopeptides were characterized by the absence of aromatic amino acids and were rich in lysine. The carbohydrate moiety of both was deficient in sialic acid and contained mannose and glucosamine. The purified glycopeptides were diluted in phosphate buffered saline, and the ciliary dyskinetic activities were compared in a double-blind fashion. Two preparations of the CF glycopeptide (1 μg/ml) revealed ciliary dyskinetic activity, whereas four control preparations did not alter ciliary rhythm, even at 50 μg/ml. The CF purified glycopeptide (10 μg/ml) caused dyskinesia within 30 seconds with swelling and accumulation of mucus-like droplets. A volcano-like appearance (see insert) was observed at a mucus gland. The glycopeptide from controls revealed no mucociliary activity and was indistinguishable from controls in medium. Abnormalities of glycoprotein metabolism have been suggested as an underlying defect in CF; the mucociliary activity of the CF glycopeptide might be part of such a generalized phenomenon. (Supported by the Cystic Fibrosis Foundation.)