ATTACHMENT OF MORAXELLA-CATARRHALIS TO PHARYNGEAL EPITHELIAL-CELLS ISMEDIATED BY A GLYCOSPHINGOLIPID RECEPTOR

Moraxella catarrhalis is one of the major pathogens of respiratory inf ections and has the ability to attach to the pharyngeal cells via fimb riae. We characterized the epithelial cell receptor to which fimbriate M. catarrhalis binds. Neuraminidase pretreatment of pharyngeal epithe lial cells resulted in a significant decrease of M. catarrhalis attach ment, suggesting interaction with the sialic acid component. The attac hment was not decreased in M. catarrhalis pretreated with 2 and 1 mg/m l of fucose, N-acetyl-neuraminic acid, N-acetyl-glucosamine, N-acetyl- galactosamine, acetyl-salicylic acid and colominic acid. However, M. c atarrhalis treated with gangliosides M1, M2, Dla, Dib and Tla at a con centration of 2.5 mu g/ml had significantly decreased the attachment c ompared to the control. Tn contrast treatment with gangliosides M3 and asialoganglioside M1 did not decrease the attachment of M. catarrhali s and thereby provided evidence for specificity of the inhibition. Con centration dependent effects of ganglioside M2 on the attachment were also observed. Other fimbriate isolates of M. catarrhalis showed decre ase in attachment after treatment with ganglioside M2. However there w as no effect on attachment when a nonfimbriate isolate was treated wit h ganglioside M2. This study indicates that the receptor of fimbriate M. catarrhalis on pharyngeal epithelial cells resides in the sequences of ganglioside M2.