Adherence of Streptococcus mutans and Streptococcus sanguis to salivary components bound to glass

Adherence of radiolabeled Streptococcus mutans and Streptococcus sanguis to saliva-treated glass surfaces was studied under conditions which minimized bacteria-glass interactions. Treatment of glass with an alkylsilane solution decreased nonspecific bacterial adherence and enhanced adsorption of radiolabeled salivary components to these surfaces. Addition of Triton X-100 to the bacterial suspensions also reduced nonspecific adherence to siliconized glass, but did not affect adherence to salivary components attached to siliconized glass. Calcium stimulated S. mutans adherence to saliva-free glass, but inhibited adherence to saliva-treated glass. S. sanguis adherence to either saliva-free or saliva-treated glass was inhibited slightly at high calcium ion concentrations. Adherence of streptococci to saliva-treated glass exhibited saturation kinetics, and the numbers of binding sites on the experimental salivary pellicle and the affinity constants for bacteria-saliva attachment were determined. Preincubation of the streptococci with whole saliva decreased their capacity to adhere to saliva-treated glass, but not to saliva-free glass. Bacteria adherent to saliva-treated glass surfaces were readily desorbed by washing with saliva. The addition of homologous antisera, ammonium sulfate-precipitated immunoglobulins, or Fab fragments to the bacterial suspensions inhibited cell adherence to saliva-treated glass.