COLLAGEN MEDIATES ADHESION OF STREPTOCOCCUS-MUTANS TO HUMAN DENTIN

Some strains of Streptococcus mutans were found to. recognize and bind collagen type I. Binding of I-125-labeled collagen type I was specifi c in that collagen types I and II, but not unrelated proteins, were ab le to inhibit binding of the labeled ligand to bacteria. Collagen bind ing to S. mutans was partially reversible and involved a limited numbe r of bacterial binding sites per cell. S. mutans UA 140 cells bound co llagen type I with high affinity (K(d) = 8 x 10(-8) M). The number of binding sites per cell was 4 x 10(4). Collagen-binding strains of S. m utans were found to adhere to collagen-coated surfaces as well as to p ulverized root tissue. S. mutans strains that did not bind the soluble ligand were unable to adhere to these substrata. Adherence to collage n-coated surfaces could be inhibited with collagen or clostridial coll agenase-derived collagen peptides. Adherence of S. mutans to dentin wa s enhanced by collagen types I and II but inhibited by collagen peptid es. S. mutans UA 140 bound significantly less I-125-collagen type I fo llowing treatment with peptidoglycan-degrading enzymes. These enzymes released a collagen-binding protein (collagen receptor) with a relativ e molecular size of 16 kDa. The results of this study suggest that col lagen mediates adhesion of S. mutans to dentin. This interaction may t arget collagen-binding strains of S. mutans to dentin in the oral cavi ty and may play a role in the pathogenesis of root surface caries.