Development of Passive Immunization System Against Dental Caries by Hen Egg Yolk Antibodies of Streptococcus Mutans.

从体外抑制变形链球菌毒力相关因子和保护变形链球菌感染大鼠龋病的角度，研究了抗变形链球菌全细胞多克隆卵黄抗体(YIgG)、无细胞(CF)葡萄糖转移酶(GTase)、细胞相关(CA)GTase、表面蛋白抗原(PAC)对变形链球菌毒力相关因子的体外抑制作用。用经甲醛处理的全细胞、纯化的CF-GTase、CA-GTase或PAC与弗氏完全佐剂联合免疫18周龄母鸡。用硫酸铵沉淀法、DEAE-Sephacel柱层析法或乙醇分级沉淀法纯化yIg G。纯化的yIg G蛋白大小为2 2 0 kDa，加入2-巯基乙醇后解离为H链和L链。对全细胞的yIg G对变形链球菌的生物体有较强的聚集作用，而对Cf-和CA-GTase的yIg G分别特异性地抑制这些GTase的活性。抗CA-GTase抗体和全细胞抗体对变形链球菌在玻璃表面的黏附有明显的抑制作用。反复重度感染变形链球菌的无特定病原体的Spraogue-Dawley大鼠和喂食#2000饮食的大鼠诱发了严重的龋齿，而喂食含有-gt；0.1%yIg G到CA-GTase的#2000饮食的大鼠在统计学上显著减少了牙菌斑的积累和龋齿的发展。给Cf-GTase注射yIg G不能预防龋病。这些结果清楚地表明，YIg G突变株CA-GTase特异性地抑制了该菌的一种毒力因子，即合成CA-GTase的不溶性葡聚糖，从而显著降低了龋病的发生。

The effect of polyclonal egg yolk antibodies (yIgG) raised against whole cells, cell-free (CF) glucosyltransferase (GTase), cell-associated (CA) GTase, surface protein antigen (PAc) of serotype c S. Mutans was examined in terms of in vitro inhibition of virulence-related factors of S. mutans and protection of S. mutans-infected rats against the development of dental caries. Hens (18 weeks old) were immunized with formalintreated whole cells, purified CF-GTase, CA-GTase or PAc together with Freund complete adjuvant. yIgG was purified by ammonium sulfate precipitation followed by DEAE-Sephacel column chromatography or fractional precipitation with ethanol. Purified yIgG was found to be a 220-kDa protein, which was dissociated into H and L chains upon addition of 2-mercaptoethanol. yIgG to whole cells gave a heavy aggregation of the organisms of S. mutans, while yIgG to CF-and CA-GTase specifically inhibited the enzymatic activity of these GTases, respectively. yIgG to CA-GTase and whole cells was found to suppress clearly the cell adherence of S. mutans to a glass surface. Specific-pathogen-free Sprague-Dawley rats that had been infected heavily and repeatedly with S. Mutans and fed diet #2000 induced severe dental caries, while rats fed diet #2000 containing>0.1% yIgG to CA-GTase resulted in a statistically significant reduction in dental plaque accumulation and caries development. Administration of yIgG to CF-GTase failed to protect against caries. These results clearly suggest that yIgG to S. mutants CA-GTase specifically inhibited a virulence factor of this organism, i. e. Insoluble glucan synthesizing CA-GTase, resulting in a significant drop in the development of dental caries.