Identification of the rhamnose-sensitive adhesin of Capnocytophaga ochracea ATCC 33596

The coaggregation of the Gram-negative microoganism Capnocytophaga ochracea ATCC 33596 with several Gram-positive bacteria, including streptococci, actinomyces and rothia, is mediated by rhamnose-sensitive adhesin(s). In the present study, MAbs against the C. ochracea adhesin(s) were prepared. These antibodies inhibited all the rhamnose-sensitive interactions, indicating that they recognize epitopes at or near the rhamnose binding site of the adhesin. The monoclonals served as probes in immunoblot analysis and recognized a polypeptide of Mr 155 K present in the wild-type organism but absent in a coaggregation defective mutant. It is concluded that the rhamnose-sensitive interactions of C. ochracea are mediated by a 155 K Mr polypeptide present on its outer surface.