乙型肝炎病毒准种特性及相互作用对抗病毒疗效影响的研究

项目名称： 乙型肝炎病毒准种特性及相互作用对抗病毒疗效影响的研究

项目编号： No.30872251

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 张欣欣

作者单位： 上海交通大学

项目金额： 33万元

中文摘要： 乙型肝炎病毒（HBV）变异而产生的准种动力学特性在核苷（酸）类似物治疗早期的动态变化特点尚未完全阐明，本课题利用聚合酶链式反应（PCR）扩增技术和克隆测序的方法研究了在拉米夫定和恩替卡韦治疗基线及治疗4 周时，HBV 逆转录酶区的准种复杂度及离散度等特征，以观察HBV 准种的动态变化特征及其与抗病毒应答的关系。同时利用体外表型研究技术对目前存在争议的rtI233V变异进行分析。研究结果显示恩替卡韦治疗应答组治疗4 周的准种离散度的净变化值与准种进化速率均比部分应答组高，与治疗的病毒学应答相关;包含准种进化参数的模型可以预测94.1%的应答者和92.9％的部分应答者;恩替卡韦组应答组与拉米夫定应答组的治疗后的准种特征明显不同；rtI233V对阿德福韦酯的耐药倍数是野毒株的6.5倍。上述研究结果提示治疗最初4 周的HBV 准种进化特征有助于预测长期病毒学应答。恩替卡韦部分应答组和拉米夫定无应答组间相似的HBV准种特征提示一种可能的耐药新机制。rtI233V变异可导致对阿德福韦酯的轻度耐药。上述结果有助于深化HBV变异及致病机制的认识,为新的抗HBV治疗方法提供理论依据.

中文关键词： 乙型肝炎病毒；准种；抗病毒治疗；耐药变异；表型研究

英文摘要： The dynamic characteristics of Hepatitis B virus (HBV) qusispecies during nucleos(t)ide analogues treatment were not well defined yet.?To investigate the evolution of HBV QS within the reverse transcriptase (RT) region during the early stage of entecavir and Lamivudine treatment and its impact on virological response, in this study, samples from patients with treatment were collcected at baseline and week 4. Clones spanning the RT region per sample were sequenced. To evaluate rtI233V mutation on adefovir resistance, in vitro phenotypic analysis was conducted.The results showed that QS complexity and diversity were comparable between responders and partial responders at baseline. However, QS complexity in responders at week 4 was statistically lower than that in partial responders at the nucleotide level, but the extent was lower than that of lamivudine group at. Net changes in diversity as well as the viral nucleotide substitution rate of responders were higher than those of partial responders, and both correlated with virological responses. A preliminary model of QS evolution variables predicted 94.1% responders and 92.9% partial responders in the entecavir group. Despite significant differences between responders to entecavir and responders to lamivudine at week 4, the characteristics of QS were quite similar between partial responders to entecavir and non-responders to lamivudine. The variant harboring rtI233V mutation exhibited a 6.5-fold decrease of suseptibility to ADV. These results suggested that the evolutionary patterns of HBV RT QS differ between responders and partial responders during the early stage of entecavir treatment. Characteristics of HBV QS evolution during the first 4 weeks contribute to the prediction of long-term virological responses. The similar patterns of HBV RT QS in partial responders and non-responders receiving different nucleoside analogues might imply a novel mechanism of drug resistance, which warrants further investigation;the emergence of a single substitution at position rtI233V is sufficient to induce resisantce to ADV. This study will provid further understanding to HBV mutation and drug resistance mechanism and more evidences for novel therapy.

英文关键词： Hepatitis B virus; quasispecies; drug resistance;antiviral theropy; phenotypic analysis