SALIVA PROTEIN-BINDING TO LAYERS OF ORAL STREPTOCOCCI IN-VITRO AND IN-VIVO

This paper reports a system for measuring saliva protein binding to or al streptococci. Enamel chips with layers of Streptococcus gordonii Bl ackburn or Streptococcus oralis 10557 were incubated in vitro with who le saliva from eight persons. Blackburn bound significantly more amyla se than 10557; no strain differences were seen for lysozyme or lactofe rrin. There were significant correlations between saliva and bound amy lase and lactoferrin. Blackburn and 10557 chips were then placed in te n subjects. Sites included the buccal left and right upper premolars a nd molars (UL, UR), labial upper central incisors (UC), and lingual lo wer central incisors (LL). That study was repeated three months later; chips with Streptococcus sanguis 13379 were also placed then. Blackbu rn bound significantly more amylase than the other strains. Blackburn and 10557 both bound the most amylase at UL and UR, and the least amyl ase at UC. However, strain 13379 bound less amylase at UL. That strain also bound significantly less sIgA at UL. All three strains bound the least sIgA at UC. Lysozyme and lactoferrin binding showed few differe nces among sites or strains. Bound protein concentrations were signifi cantly correlated across sites and strains within subjects, but not co rrelated with whole saliva. Strain differences may reflect species dif ferences in amylase binding, or differences in species-specific sIgA t iters. Site differences may indicate local variation in protein availa bility. Differences between chip correlations with whole saliva in vit ro and in vivo suggest that the salivary film may be modified as it fl ows over tooth surfaces.