COMBINED INHIBITORY EFFECT OF BOVINE IMMUNE WHEY AND PEROXIDASE-GENERATED HYPOTHIOCYANITE AGAINST GLUCOSE-UPTAKE BY STREPTOCOCCUS-MUTANS

Immune whey product was obtained from Streptococcus mutans- and Strept ococcus sobrinus-immunized cows. Hypothiocyanite (HOSCN/OSCN-) was gen erated in VMG-buffer, pH 5.5 or 6.5, by bovine milk lactoperoxidase, K SCN and hydrogen peroxide. The glucose incorporation by late-log cells of S. mutans 10449, serotype c, was followed by measuring the uptake of C-14-glucose at 37 degrees C. At pH 5.5 and 6.5 both immune whey pr oduct and HOSCN/OSCN- dose-dependently inhibited glucose uptake. The i nhibition by their combination was additive if bacterial cells were tr eated with HOSCN/OSCN- before exposed to immune whey product. In contr ast to immune whey product, the control product from sham-immunized co ws increased the glucose uptake even when added simultaneously with HO SCN/OSCN-. However, when bacterial cells were pretreated with HOSCN/OS CN- an enhanced inhibitory effect was observed also with control produ ct. The results indicate that colostral proteins from S. mutans- or S. sobrinus-immunized cows inhibit glucose uptake and that the effect is enhanced by pretreatment with lactoperoxidase-generated HOSCN/OSCN-.