乙型肝炎病毒"a"决定簇突变对乙型肝炎疫苗保护效果的影响

目的研究乙型肝炎（乙肝）病毒（HBV）“a”决定簇热点突变对乙肝疫苗保护效果的影响。方法根据HBV基因保守序列设计PCR扩增引物,针对“a”决定簇突变设计简并探针,制备检测HBV“a”决定簇16种热点突变的基因芯片,并用克隆测序对芯片检测结果进行验证。基因芯片法检测47对乙肝疫苗阻断失败的母婴配对样本和323例阻断成功的母亲样本。结果克隆测序证明,基因芯片法具有特异性。应用该法检测发现,野生株（阳性率为78．66%）仍为主要流行株,依次为126A（11．27%）、145R（5．76%）、126S-1（5．28%）、126S-2（4．56%）、129H（1．20%）、144A（0．72%）、129R（0．24%）,但126A阳性率显著高于其他突变（P值均＜0．01）。阻断失败组母婴均感染的样本与阻断成功组的126A、126S-1、126S-2和145R检出率的差异无统计学意义。结论现有乙肝疫苗可阻断126A、126S和145R突变株的母婴传播,目前毋需研制针对126和145位点突变的新型乙肝疫苗,但需加强对突变株的流行病学监测。

Role of mutations on the "hepatitis B virus 'a' determinant hotpoint" to the efficacy of hepatitis B vaccine

OBJECTIVE: To study how hepatitis B virus(HBV) 'a' determinant hotpoint mutations were influecing the hepatitis B vaccine efficacy. METHODS: Primers were designed in HBV conservative region, and the degenerate probes for detecting 16 'a' determinant hotpoint mutations were developed for gene chips. Sensitivity and specificity of the gene chips were evaluated by clone sequencing. Sera of 47 pairs of mothers and infants with immune failure and 323 mothers of children with immune protection of HB vaccine were detected by the gene chips. RESULTS: Result from clone sequencing demonstrated that the gene chips were specific for the detection of 'a' determinant hotpoint mutations. The wild type of HBV was still dominant, with the prevalence of 78.66%, and the mutation frequencies of 126A, 145R, 126S-1, 126S-2, 129H, 144A, and 129R were 11.27%, 5.76%, 5.28%, 4.56%, 1.20%, 0.72% and 0.24%, respectively. The prevalence of 126A mutation was significantly higher than that of other mutations(P < 0.01). No significant differences were found in mother-infant transmission rates of 126A, 126S-1, 126S-2 and 145R variants. CONCLUSION: The currently available hepatitis B vaccine could block mother-infant transmission of 126A, 126S and 145R variants. It appears that there is no need to develop a new hepatitis B vaccine against 126 and 145 variants at present, but the consistent epidemiological surveillance on HBV mutants should be carried out.