A Flagellin-Adjuvanted Trivalent Mucosal Vaccine Targeting Key Periodontopathic Bacteria

Periodontal disease (PD) is caused by microbial dysbiosis and accompanying adverse inflammatory responses. Due to its high incidence and association with various systemic diseases, disease-modifying treatments that modulate dysbiosis serve as promising therapeutic approaches. In this study, to simulate the pathophysiological situation, we established a "temporary ligature plus oral infection model" that incorporates a temporary silk ligature and oral infection with a cocktail of live (), (), and () in mice and tested the efficacy of a new trivalent mucosal vaccine. It has been reported that , a red complex pathogen, amplifies periodontitis severity by interacting with periodontopathic bacteria such as and . Here, we developed a recombinant mucosal vaccine targeting a surface-associated protein, BspA, of by genetically combining truncated BspA with built-in adjuvant flagellin (FlaB). To simultaneously induce -, -, and -specific immune responses, it was formulated as a trivalent mucosal vaccine containing -FlaB-tBspA (BtB), -Hgp44-FlaB (HB), and -FlaB-tFomA (BtA). Intranasal immunization with the trivalent mucosal vaccine (BtB + HB + BtA) prevented alveolar bone loss and gingival proinflammatory cytokine production. Vaccinated mice exhibited significant induction of tBspA-, Hgp44-, and tFomA-specific IgG and IgA responses in the serum and saliva, respectively. The anti-sera and anti-saliva efficiently inhibited epithelial cell invasion by and and interfered with biofilm formation by . The flagellin-adjuvanted trivalent mucosal vaccine offers a novel method for modulating dysbiotic bacteria associated with periodontitis. This approach leverages the adjuvant properties of flagellin to enhance the immune response, aiming to restore a balanced microbial environment and improve periodontal health.