EVIDENCE FOR LECTIN-MEDIATED ADHERENCE OF MORAXELLA-CATARRHALIS

Clinical isolates of Moraxella catarrhalis (n=86) were evaluated for t heir haemagglutinating activity with different types of erythrocytes. Of all the isolates tested, 12 did not agglutinate with any of the ery throcytes, whereas 65 reacted with human erythrocytes of type A, B, an d 0, and 26 with erythrocytes from rabbit, guinea pig, dog, or rat. No ne of the isolates agglutinated with sheep and goat erythrocytes. The agglutination titres ranged from 0 to 64. Among these isolates, 13 dif ferent agglutination patterns could be distinguished. The agglutinatin g activity was Ca2+-dependent and was inhibited by proteases, by tempe ratures exceeding 50 degrees C and by the addition of D-glucosamine or D-galactosamine. The adherence capacity of the M. catarrhalis isolate s to tracheal epithelium correlated with their agglutination titre and could be inhibited by the same treatments. These data provide strong evidence that adherence of M. catarrhalis is mediated by lectins locat ed on the bacterial surface.