ROLE OF CATIONS AND IGA IN SALIVA-MEDIATED AGGREGATION OF PSEUDOMONAS-AERUGINOSA IN CYSTIC-FIBROSIS PATIENTS

Oral colonization by Pseudomonas aeruginosa possibly precedes the pulm onary infection process in cystic fibrosis (CF) patients. As bacterial aggregates may play a role in establishment of pulmonary infections, involvement of IgA and cations in CF patient saliva-mediated aggregati on of P. aeruginosa was investigated. For colonized patients, P aerugi nosa aggregation correlated with bacterial-specific and total salivary IgA. Cation or IgA depletion reduced P aeruginosa aggregation by sali va from all patients. However, if cations were removed before IgA, and saliva was then reconstituted with calcium, only colonized patient sa liva showed reduced aggregation. Aggregation by IgA-depleted saliva wa s augmented by reconstituting with original IgA. CF patient saliva-med iated aggregation of P aeruginosa thus is cation-dependent and enhance d by bacterial-specific IgA. Characterizing the interactions among bac terial aggregating factor(s), cations, and antibodies in CF saliva wil l help clarify the link between P aeruginosa oral colonization and pul monary infections in CF patients.