Development of bovine milk antibody to prevent dental caries

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Cell surface Protein antigen(PAc) and water-insoluble glucan-synthesizing enzyme(GTF-I) produced by cariogenic Streptococcus mutans are two major factors implicated in the colonization of the human oral cavity by this bacterium. We examined the effect of bovine milk, produced after immunization with a fusion protein of functional domains of these proteins, on the recolonizaion of S.mutans. To prerare immune milk, a pregnant Holstein cow was immunized with the fusion protein PAcA-GB, a fusion of the saliva-binding alanine-rich region(PAcA) of PAc and the glucan-binding(GB) domain of GTF-I. After eight adult subjects received cetylpyridinium chloride(CPC) treatment, one subgroup(n=4) rinsed their mouths with immune milk arid a control group(n=4) rinsed with nonimmune milk. S.mutans levels in saliva and dental plaque decreased after CPC treatment in both groups. Mouth rinsing with immune milk significantly inhibited recolonization of S.mutans in saliva and plaque. On the other hand, the n … More umber of S.mutans cells in saliva and plaque in the control group increased immediately after the CPC treatment and surpassed the baseline level 42 and 28 days, respectively, after the CPC treatment. The ratios of S.mutans to total streptococci in saliva and plaque in the group that received immune milk were lower than those in the control group. These results suggest that milk produced from immunized cow may be useful for controlling S.mutans in the human oral cavity.We examined the effect of the immune milk on the cariogenicity of S.mutans in a rat model. Concentrated immune milk was fed to rats once a day for 55 days. The group that received immune milk had significantly less caries development than controls.The bovine lactoferrin molecule and relatively long lactoferrin fragments containing residues 473 to 538 strongly inhibited adherence of S.mutans to saliva-coated hydroxyapatite beads. Each cysteine residue in Lf411(residents 473 to 538) was replaced by a serine residue, and the mutants Lf411-C481S and Lf411-C532S strongly inhibited S.mutans adherence. These results suggests that the functional domain of lactoferrin that binds to a salivary film lies in residues 473 to 538 and that region might be concealed by disulfide bond formation between Cys481 and Cys532 in the Lf411 fragment. Less