Additionally, FomA has been recognized as a major immunogen of F. nucleatum [16] and [17]. Intriguingly, it has been reported that FomA is involved in binding between fusobacteria and Streptococcus sanguis on the tooth-surface and to Porphyromonas gingivalis (P. gingivalis)

in the periodontal pockets [18], supporting the view that FomA acts as a receptor protein in co-aggregation with other oral pathogenic bacteria. Thus, FomA is a potential target for the prevention of bacterial co-aggregation. Nutlin3a Classical treatments for periodontal diseases involve not only mechanical and antibiotic therapies but also surveillances on dynamic processes including the periodontopathogenic bacteria and the host responses. Chemical antiseptics are also used for treatments of periodontitis and halitosis. However, most of the chemical antiseptics fail to cure chronic, severe periodontitis and halitosis. Treatments using multiple doses of antibiotics to cure infection-induced periodontitis and halitosis have risks of generating resistant Ibrutinib nmr strains and misbalancing the resident

body flora [19]. In addition, even though bacteria in the dental biofilm can invade the periodontal tissues, most of bacteria located in the dental biofilm and outside the host tissues are inaccessible to antibiotics. The treatments of periodontitis and halitosis have not been significantly improved during the past 40 years due to the lack of focus on the awareness that these diseases are polymicrobial diseases as opposed to mono-infections. Vaccines targeting oral bacteria [such as Streptococcus mutans (S. mutans) for dental caries; P. gingivalis Resveratrol for periodontitis] are currently being evaluated [20] and [21]. However, these vaccines cannot combat the enhanced pathogenesis (e.g. co-aggregation/biofilms) by F. nucleatum. Since the plaque biofilm is a common feature for almost all oral

bacteria, blocking the bacterial co-aggregation at an early stage in biofilm formation will broadly prevent various biofilm-associated oral diseases including periodontitis and halitosis [22]. In the study, we demonstrate that F. nucleatum FomA is immunogenic, and that mice immunized with FomA produce neutralizing antibodies which prevent bacterial co-aggregation and, also gum abscesses and halitosis associated with co-aggregation. Moreover, immunization with FomA conferred a protective effect on bacteria-induced gum swelling and decreased the production of macrophage-inflammatory protein-2 (MIP-2) cytokine. These findings envision a novel infectious mechanism by which F. nucleatum interacts with P. gingivalis to aggravate oral infections. Moreover, this work has identified FomA as a potential molecular target for the development of drugs and vaccines against biofilm-associated oral diseases. F. nucleatum (ATCC® 10953) and P. gingivalis (ATCC® 33277) were cultured in 4% (w/v) trypticase soy broth (TSB, Sigma–Aldrich, St. Louis, MO) supplemented with 0.