Development of bovine milk antibody to prevent dental caries

致龋性变形链球菌产生的细胞表面蛋白抗原(PAC)和水不溶性葡聚糖合成酶(GTF-I)是该菌在口腔中定植的两个主要因素。我们检测了用这些蛋白功能区的融合蛋白免疫后产生的牛乳对变形链球菌重新克隆的影响。为了预制免疫乳，将PACA-GB融合蛋白免疫一头怀孕荷斯坦奶牛，该融合蛋白是PAC的唾液结合富含丙氨酸区域(PACA)和GTF-I的葡聚糖结合(GB)区域的融合。在8名成人受试者接受十六烷基氯吡啶(CPC)治疗后，一组(n=4)用免疫牛奶漱口，另一组(n=4)用非免疫牛奶漱口。经CPC治疗后，两组患者唾液和牙菌斑中变形链球菌水平均有所下降。用免疫乳漱口可显著抑制唾液和菌斑中变形链球菌的再繁殖。另一方面，n…对照组唾液和菌斑中变形链球菌细胞数在CPC治疗后即刻增加，分别在治疗后第42天和28天超过基线水平。免疫乳组唾液和菌斑中变形链球菌占总链球菌的比例均低于对照组。这些结果表明，免疫奶牛生产的牛奶可能有助于控制人类口腔中的变形链球菌。我们在大鼠模型上检测了免疫牛奶对变形链球菌致龋性的影响。每天给大鼠喂一次免疫浓缩乳，连续55天。接受免疫牛奶的那一组患龋齿的几率明显低于对照组。牛乳铁蛋白分子和含有残基473到538的相对较长的乳铁蛋白片段强烈地抑制变形链球菌对唾液包裹的羟基磷灰石微珠的黏附。Lf411(居民点473~538)的每个半胱氨酸残基都被丝氨酸残基取代，突变株Lf411-C481S和Lf411-C532S强烈抑制变形链球菌的黏附。这些结果表明，乳铁蛋白与唾液膜结合的功能结构域位于残基473到538，该区域可能被Lf411片段中Cys481和Cys532之间的二硫键所掩盖。较少

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