Immunization with cell-free-generated vaccine protects from Porphyromonas gingivalis-induced alveolar bone loss

Abstract

Introduction: Periodontal diseases (PD) are complex oral inflammatory diseases initiated by keystone bacteria such as Porphyromonas gingivalis. A vaccine for PD is desirable as clinical treatment involves protracted maintenance strategies aimed to retain dentition. Although prior immunization approaches targeting P. gingivalis have reported variable success in limiting facets of disease such as oral bone loss, it remains that a vaccine for this disease may be attainable.

Aim: To investigate cell-free protein synthesis (CFPS) as a platform to produce vaccinable targets suitable for efficacy testing in a P. gingivalis-induced murine oral bone loss model.

Materials and methods: Recombinantly generated P. gingivalis minor fimbriae protein (Mfa1), RgpA gingipain hemagglutinin domain 1 (HA1), and RgpA gingipain hemagglutinin domain 2 (HA2) were combined in equivalent doses in adjuvants and injected intramuscularly to immunize mice. Serum levels of protein-specific antibody were measured by ELISA, and oral bone levels were defined by morphometrics.

Results: Recombinantly generated P. gingivalis proteins possessed high fidelity to predicted size and elicited protein-specific IgG following immunization. Importantly, immunization with the vaccine cocktail protected from P. gingivalis elicited oral bone loss.

Conclusion: These data verify the utility of the CFPS technology to synthesize proteins that have the capacity to serve as novel vaccines.

Keywords: Porphyromonas gingivalis; cell-free protein synthesis; gingipain; immunization; minor fimbriae; oral bone loss.