Characterization of a novel N-acetylneuraminic acid-specific Fusobacterium nucleatum PK1594 adhesin.

Fusobacterium nucleatum has been identified as significantly associated with sites with active periodontal disease and, as a group, the oral fusobacteria coaggregate with members of all oral bacteria genera tested. Monoclonal antibodies were prepared and used in conjunction with other potential inhibitors, such as simple sugars and amino acids, to characterize coaggregation interactions, of F. nucleatum PK1594. Four unique monoclonal antibodies, 5H11, 14C7, 19F2 and 29C12, were obtained by their ability to inhibit coaggregation of F. nucleatum PK1594 with Actinomyces israelii PK16. They were also capable of inhibiting other coaggregations including Streptococcus oralis H1, S. oralis J22, Capnocytophaga ochracea ATCC33596, Prevotella denticola PK1277 and Prevotella intermedia PK1511. All of these interactions were completely inhibited by N-acetylneuraminic acid. Neither N-acetylneuraminic acid nor monoclonal antibody 5H11 had any inhibitory effect on other F. nucleatum PK1594 interactions, including all galactose-inhibitable coaggregations. The results indicate that F. nucleatum PK1594 expresses upon its surface a distinct type of adhesin that mediates coaggregation interactions that are inhibited by N-acetylneuraminic acid.