INTERACTIONS BETWEEN GLYCOCONJUGATES FROM HUMAN RESPIRATORY AIRWAYS AND PSEUDOMONAS-AERUGINOSA

Pseudomonas aeruginosa binds to different glycoconjugates in vitro. As six other bacteria, it binds to several glycolipids, mainly asialo GM 1 and asialo GM2. Asialo GM1 has been reported to exist at the surface of cystic fibrosis cells. The binding of P. aeruginosa to asialo GM1 involves the pill, especially the C-terminal part of pilin that recogn izes the GalNAc(beta 1,4)Gal sequence of asialo GM1. P. aeruginosa may also bind to sialylated membrane-bound glycoproteins. Human salivary and respiratory mucins are also recognized by P. aeruginosa. Mucins re present the main components of mucus. The peptide part (apomucin) of t his broad family of secreted glycoproteins is encoded by several mucin genes. The apomucins are covered by a large number of carbohydrate ch ains that can be remarkably different and represent a mosaic of sites for attachment of microorganisms. The binding of P. aeruginosa to muci ns involves outer membrane proteins and mucin carbohydrate chains that are structurally different from the carbohydrate recognized by pilin. Airway and salivary mucins secreted by patients suffering from cystic fibrosis (CF) show alterations in their carbohydrate moiety. The incr eased sulfation of airway mucins seems to correspond to a primary defe ct. Other abnormalities such as increased sialylation or fucosylation have also been detected. The binding of P. aeruginosa to airway or sal ivary mucins is increased in CF. However, the precise link between the carbohydrate alterations and the increased binding of P. aeruginosa t o CF mucins remains to be elucidated.