This invention relates to a peptide selected from the group: FLLDADHNTFGSVIPATGPLFTGTASS LYSANFESLIPANADPVVTTQNIIVTG LYSANFEYLIPANADPVVTTQNIIVTG TNPEPASGKMWIAGDGGNQP RYDDFTFEAGKKYTFTMRRAGMGDGTD DDYVFEAGKKYHFLLLMKKMGSGDGTE TNPEPASGKMWIAGDGGNQPARYDDFTFEAGKKYTFTMRRAGMGDGTD NTFGSVIPATGPL PASGKMWIAGDG EAGKKYTFTMRRA EAGKKYHFLMKKM. It also relates to compositions and use of these peptides for treating and testing Porphyromonas gingialis. 展开▼