The invention provides a composition for use in raising an immune response to P. gingivalis in a subject, the composition comprising an amount effective to raise an immune response of a polypeptide having an amino acid sequence substantially identical to at least 50 amino acids, or an antigenic or immunogenic portion, of a polypeptide corresponding to accession number AAQ66654. The invention also provides a method of preventing or treating a subject for P. gingivalis infection comprising administering to the subject a composition of the invention.
