An antiserum to a synthetic fimbrial peptide of Actinobacillus actinomycetemcomitans blocked adhesion of the microorganism.

The purpose of this study is to certify the importance of the fimbriae as an attachment factor of Actinobacillus actinomycetemcomitans, a human periodontopathic bacterium, and the significance of anti-fimbrial antibody function as an attachment inhibitor. Fimbrial antigen was prepared from the A. actinomycetemcomitans 310-a strain. Oligopeptides were synthesized according to the amino acid sequence of the fimbrial protein. The peptide antigen was conjugated with branched lysine polymer resin beads. The peptide antigen was suspended in PBS emulsified with incomplete Freund's adjuvant and used to immunize rabbits. A rabbit antiserum reacted with an approximately 54 kDa protein of the fimbriae protein from A. actinomycetemcomitans 310-a and with those of other fimbriated strains. This antiserum strongly inhibited the attachment of fimbriated A. actinomycetemcomitans strains to saliva-coated hydroxyapatite beads, buccal epithelial cells, and a fibroblast cell line, Gin-1. Such a synthetic fimbrial peptide antigen may be effective in inducing antibodies which inhibit adhesion and subsequent colonization by A. actinomycetemcomitans.