Streptococcus mutans　ト　スイエキ　タンパクシツ　ノ　ハンノウ　ニ　オヨボス　ラクトフェリン　ノ　サヨウ

Streptococcus mutans has been implicated as the prime cause of dental caries, one of the most common diseases in humans. In the oral cavity, there are two types of bacterial interaction with salivary components; saliva-induced bacterial aggregation in solution phase, and bacterial adherence to salivary components adsorbed on the tooth surface. As for S. mutans cells, a 190-kDa surface protein antigen of the organism (PAc) is responsible for these interactions. We have recently shown that bovine milk lactoferrin inhibits both the saliva-induced S. mutans aggregation and the adherence of the organism to a salivary film by binding strongly to salivary agglutinin. Using deletion analysis, we also demonstrated that amino acid residues 473 to 538 of lactoferrin (Lf411) are implicated in these activities. Several studies have demonstrated that salivary agglutinin is a member of the scavenger receptor cysteine-rich (SRCR) superfamily, and the S. mutow-binding peptide domain on salivary agglutinin was revealed to be SRCRP2 peptide. We have recently shown that both the rPAc of S. mutans and bovine lactoferrin bind to peptide domain SRCRP2 of salivary agglutinin, and that lactoferrin inhibits the interaction between rPAc and SRCRP2. The lactoferrin residues from 480 to 492 are important for this inhibition, and the peptide corresponding to this region could be used as an inhibitor of S. mutans adherence to a salivary film