An immunogenic composition, a periodontal vaccine formulation containing the immunogenic composition, and methods for treating or preventing periodontal disease are provided, where the methods involves administering an immunologically effective amount of the composition or vaccine formulation to a subject. The immunogenic composition contains at least one polypeptide that comprises: an Mfa1 antigen sequence that is substantially homologous to an immunogenic amino acid sequence from an Mfa1 fimbrilin protein of a Porphyromonas bacterium； and an HA1 antigen sequence, an HA2 antigen sequence, or both an HA1 antigen sequence and an HA2 antigen sequence, wherein the HA1 antigen sequence is substantially homologous to an immunogenic amino acid sequence from an RgpA Gingipain hemagglutinin domain 1 contained within an RgpA Gingipain protein of a Porphyromonas bacterium, and the HA2 antigen sequence is substantially homologous to an immunogenic amino acid sequence from an RgpA Gingipain hemagglutinin domain 2 contained within an RgpA Gingipain protein of a Porphyromonas bacterium.
