HBV在宫内传播途径的分子进化特点研究

目的 探讨乙型肝炎病毒(HBV)的宫内传播的分子进化特点.方法 选择有乙型肝炎母子无症状携带者两对母子的血清样本分离HBV准种病毒株,进行PCR-克隆-测序后,构建遗传进化树及拓扑结构比较,计算每对母子准种种群内及种群间的进化距离.结果 2个进化树包括2种类型,第1种类型,大部分母亲株聚集为一枝,但新生儿株与小部分母亲株聚集在另一枝,母亲株为新生儿株的起源.第2种类型,母亲株与新生儿株未形成总的单源群,也没形成各自的单源群,有1株新生儿的病毒株为大部分母子序列的起源.结论 两组病例的传播途径分别符合"胎盘泄漏"和"细胞途径"特点.

A study on molecular evolution characters of intrauterine transmission route of HBV

Objective To study the characters of the molecular evolution of the intrauterine transmission route of HBV.Methods The quasispecies isolated from two pairs of HBsAg-positive mothers and their neonates,who were infected with HBV by intrauterine transmission,were selected as study subjects.After PCR-cloning-sequencing,the phylogenetic trees of the HBV strains of each pair of mother and neonate were constructed,the topological structures were compared,and the distance between and within the quasispecies was calculated.Results The two phylogenetic trees included two types.In the first type,most of the maternal sequences clustered into one clade,the neonatal sequences and some of maternal sequences clustered into another clade.One of maternal strains was the ancestor of the neonatal strains.In the second type,the sequences of the mothers and neonates could form neither a monophyletic cluster nor separate monophyletic clusters.One of the neonatal strains was the ancestor of most strains of mother and neonate.Conclusion The characters of the molecular evolution of the two cases were separately accorded with those of ’placental leakage’ and ’cellular route’.