变异链球菌的传播、定植及其与唾液sIgA的关系

Transmission and colonization of inutans streptococci and its relationship with natural salivary sIgA

目的利用夫妻配对模式,纵向监测变异链球菌的基因型,探讨其传播和定植的特点,以及唾液sIgA与不同基因型菌株的免疫印迹的差异。方法选择9对夫妻,取口腔唾液和牙菌斑的样本,计数唾液中变链菌数,牙菌斑中变链菌分离株采用PCR技术鉴定菌种,限制性核酸内切酶分析REA基因型。每隔2个月取样1次,经过3次跟踪鉴定分离菌株的基因型。Western blot分析个体唾液sIgA与自身变链菌株、配偶菌株、2株参考菌株GS-5、Ingbritt C的免疫印迹反应。结果(1)变链菌菌株的定植是稳定的,一般只有1-2种基因型。在正常成年人群,变链菌可以出现短暂的一过性传播,但外源性变链菌株难以长期定植。(2)个体sIgA对自身菌株的免疫印迹可以不同于对配偶的反应。(3)不同唾液sIgA对参考菌株的免疫印迹存在个体差异。结论个体变异链球菌在口腔中的定植是稳定的,该菌株的定植和对外源性菌株的排斥不是由sIgA单因素决定的。

Objective To investigate the transmission and colonization of mutans streptococci in adults by genotype monitoring and identify the natural salivary sIgA activity by a spouse model. Methods Clinical mutans streptococci were isolated from 9 pairs of couple volunteers, serotyped by biochemical test and PCR, and genotyped by REA. The indigenous strain of subject was identified three times at a three-month interval. Unstimulated secretions from submandibular glands and sublingual glands were collected by modified collectors, sIgA activity to different Streptococcus mutans genotypes was detected by Western blot. Results （ 1 ） The colonization of mutans streptococci was stable in adults. （2） Subjects had different sIgA activity to different genotype strains, and there was no common specific recognition bands to exogenous strains. （3） Immunoreactivity to the same reference strain could be different among individuals. Conclusion The colonization of mutans strepococci was stable in adults. The naturally induced sIgA antibody activity does not function as a significant factor in the prevention of transmission of exogenous mutans streptococci and the colonization of indigenous strains.