宫内感染乙型肝炎病毒的新生儿及其母亲HBV基因结构分析

Structural analysis of hepatitis B virus genomes from mothers and neonates infected by HBV in uterus

目的 :探讨HBV基因变异与宫内感染的关系 .方法 :扩增 2对发生宫内感染的新生儿及母亲血清中 2 5kbHBVDNA ,克隆、测序并分析其基因结构 .同时用免疫染色法检测孕妇胎盘组织HBsAg .结果 :母婴HBVDNA序列中 ,前S1、前S2和S区都发生突变并且导致相应编码蛋白的氨基酸组成发生改变 ,其中以前S2区突变率为最高 (P <0 0 1) ;而前C、C区基因只有少数核苷酸发生沉默突变 .孕妇胎盘组织各层细胞中均有HBsAg阳性信号 .结论 :新生儿HBV的细胞源性宫内感染可能主要与HBV突变株的前S/S区的基因变异有关 ,而前C/C区相对比较保守 。

AIM: To investigate the relationship between intrauterine HBV infection and gene variation. METHODS: 2 5 kb HBV DNA fragments were amplified by PCR from sera of two neonates infected with HBV in uterus and sera of their mothers. These DNA fragments were cloned and sequenced, and the mutations were analyzed. The placentas were detected for HBsAg by immunohistochemical method. RESULTS: In both the fragments of neonates and their mothers, there were mutations in preS1, preS2, and S regions and the amino acid sequences encoded by those regions also changed. The rate of divergence in preS2 was the highest, while the mutations in preC/C were few and silent. CONCLUSION: There may be some relationship between intrauterine HBV infection through the so called cellular route and mutations in preS1, preS2, and S regions, while preC/C regions may be conservative and bear no significant relationship with intrauterine HBV infection.