A 200 KDA PROTEIN IS ASSOCIATED WITH HEMAGGLUTINATING ISOLATES OF MORAXELLA (BRANHAMELLA) CATARRHALIS

Moraxella catarrhalis adheres to human erythrocytes by means of a prot einaceous, trypsin sensitive, heal modifiable haemagglutinin. A 200 kD a protein was found to be associated with haemagglutinating isolates o f M. catarrhalis. This protein was present on all haemagglutinating is olates (n = 17), but was absent on the non-haemagglutinating isolates (n = 23) examined. This protein demonstrated heat-modifiable propertie s in sodium dodecyl sulfate and was degraded by trypsin. Immunoblot as says with polyclonal antiserum indicated that the 200 kDa protein was associated exclusively with haemagglutinating isolates and antibodies to this protein did not recognise epitopes on non-haemagglutinating is olates. This protein, which appears to be a surface expressed protein may be a haemagglutinin of M. catarrhalis.