Prevention, treatment and diagnosis of P. gingivalis infection

A method of reducing the secerity of a P. gingivalis-related disease or condition in a subject, comprising administering to the subject an antibody raised against a chimeric or fusion protein comprising a first peptide joined directly or through a linker to a second peptide or polypeptide, wherein:

• (A) said first peptide comprises a region of a P. gingivalis trypsin-like enzyme selected from the group consisting of the amino acid sequence that is the same as, or at least 90% homologous to, the sequence shown in any one of SEQ ID NOs:
• 1-34;
• and
• (B) said second peptide or polypeptide is selected from the group consisting of:
• (i) the amino acid sequence that is the same as, or at least 90% homologous to, the sequence of an adhesin domain of the Lys-X-proteinase of P. gingivalis shown in any one of SEQ ID NOs:
• 35-37 and 40-43;
• and
• (ii) the amino acid sequence that is the same as, or at least 90% homologous to, the sequence of an adhesin domain of the Arg-X-proteinase of P. gingivalis shown in any one of SEQ ID NOs:
• 38-39 and 44-46;
• (iii) the amino acid sequence that is the same as, or at least 90% homologous to, the sequence of a HagA adhesin domain of P. gingivalis shown in any one of SEQ ID NOs:
• 80-82;
• and
• (iv) the amino acid sequence that is the same as or at least 90% homologous to, the sequence shown in any one of SEQ ID NOs:
• 69-79 and 83 to 85.