A built-in adjuvant-engineered mucosal vaccine against dysbiotic periodontal diseases

Periodontitis is associated with a dysbiotic shift in the oral microbiome. Vaccine approaches to prevent microbial shifts from healthy to diseased state in oral biofilms would provide a fundamental therapeutic strategy against periodontitis. Since dental plaque formation is a polymicrobial and multilayered process, vaccines targeting single bacterial species would have limited efficacy in clinical applications. In this study, we developed a divalent mucosal vaccine consisting of a mixture of FlaB-tFomA and Hgp44-FlaB fusion proteins targeting virulence factors of inflammophilic bacteria Fusobacterium nucleatum and Porphyromonas gingivalis, respectively. Introduction of peptide linkers between FlaB and antigen improved the stability and immunogenicity of engineered vaccine antigens. The intranasal immunization of divalent vaccine induced protective immune responses inhibiting alveolar bone loss elicited by F. nucleatum and P. gingivalis infection. The built-in flagellin adjuvant fused to protective antigens enhanced antigen-specific antibody responses and class switch recombination. The divalent vaccine antisera recognized natural forms of surface antigens and reacted with diverse clinical isolates of Fusobacterium subspecies and P. gingivalis. The antisera inhibited F. nucleatum-mediated biofilm formation, co-aggregation of P. gingivalis and Treponema denticola, and P. gingivalis-host cell interactions. Taken together, the built-in adjuvant-engineered mucosal vaccine provides a technological platform for multivalent periodontitis vaccines targeting dysbiotic microbiome.