Mucin glycosylation changes in cystic fibrosis lung disease are not manifest in submucosal gland secretions

SMG (submucosal gland) secretions are a major component of the airway surface liquid, are associated with innate immunity in the lung, and have been reported to be altered in lung disease. Changes in lung mucosal glycosylation have been reported in CF (cystic fibrosis), which may be responsible for differential bacterial binding to glycosylated components in the lung mucosa and hence increased pre-disposition to pulmonary infection. Glyco-proteomic analysis was performed on SMG secretions collected from explanted bronchial tissue of subjects with severe lung disease, with and without CF, and controls without lung disease. Mucins MUC5B and MUC5AC were shown to be the dominant high-molecular-mass glycoprotein components, with a minor nonmucin glycoprotein component, gp-340, also present. Oligosaccharides containing blood-group determinants corresponding to subjects' blood type were abundant on MUC5B/MUC5AC, as were Lewis-type epitopes and their sialylated analogues, which