Effectiveness of egg yolk immunoglobulin (IgY) against periodontal disease-causing Fusobacterium nucleatum.

AIMS: To evaluate the in vitro and in vivo effectiveness of egg yolk immunoglobulin (IgY) against periodontal disease-causing Fusobacterium nucleatum.

METHODS AND RESULTS: Four White Leghorn hens (120 days old) were immunized with whole Fus. nucleatum cells killed with 1% formaldehyde using three injections provided at 2-week intervals. IgY was produced from egg yolks obtained from these immunized hens using water dilution, two-step salt precipitation and ultrafiltration. This IgY was shown to have a purity of 86·8% based on its optical intensity in the stained SDS-PAGE bands. An enzyme-linked immunosorbent assay indicated a high specificity for the IgY against Fus. nucleatum with a maximum antibody titre of 80 000. The IgY had only weak cross-reactivity with Porphyromonas gingivalis, Prevotella intermedia and Solobacterium moorei. Growth and biofilm formation by Fus. nucleatum were inhibited by IgY at concentrations of 10 and 20 mg ml(-1) . Immunofluorescence and immunoelectron microscope assays revealed a high binding ability of specific IgY, which may explain the in vitro effectiveness of IgY. In an in vivo study, IgY treatment resulted in a marked decrease in alveolar bone loss after Fus. nucleatum infection in a mouse model confirming the effectiveness of IgY against periodontal disease-causing Fus. nucleatum.

CONCLUSIONS: IgY effectively inhibited growth and biofilm formation by Fus. nucleatum and prevented the progression of periodontal disease by decreasing alveolar bone loss.

SIGNIFICANCE AND IMPACT OF THE STUDY: Specific IgY may have potential for the treatment of periodontal disease.