Allen M I, Deslauriers M, Andrews C W, Tipples G A, Walters K A, Tyrrell D L, Brown N, Condreay L D
Department of Virology, Glaxo Wellcome Inc., Research Triangle Park, NC 27709-3398, USA.
Hepatology. 1998 Jun;27(6):1670-7. doi: 10.1002/hep.510270628.
Cirrhosis and hepatocellular carcinoma occur as long-term complications of chronic hepatitis B virus (HBV) infection. Antiviral therapy is potentially a successful approach for the treatment of patients with HBV infection, which includes the nucleoside analog, lamivudine [(-)2'-deoxy-3'-thiacytidine, 3TC]. Although resistance to lamivudine therapy has been reported in several HBV-infected patients, the pattern of resistance-associated mutations in HBV has not been fully characterized. We report a DNA sequence database that includes a 500-base pair region of the HBV polymerase gene from 20 patients with clinical manifestations of lamivudine resistance. Analysis of the database reveals two patterns of amino acid substitutions in the tyrosine, methionine, aspartate, aspartate (YMDD) nucleotide-binding locus of the HBV polymerase. HBV DNA from the sera of patients in Group I exhibits a substitution of valine for methionine at residue 552, accompanied by a substitution of methionine for leucine at residue 528. Patients in Group II had only an isoleucine-for-methionine substitution at position 552. Reconstruction of these mutations in an HBV replication-competent plasmid was performed in a transient transfection cell assay to determine the function/relevance of these mutations to lamivudine resistance. Both Group I and Group II mutations resulted in a substantial decrease in sensitivity to lamivudine treatment (> 10,000-fold shift in IC50 over wild-type [wt] IC50), strongly indicating that these mutations were involved in resistance to lamivudine. A hypothetical model of the HBV reverse transcriptase has been generated for further study of the role of these mutations in lamivudine resistance.
肝硬化和肝细胞癌是慢性乙型肝炎病毒（HBV）感染的长期并发症。抗病毒治疗可能是治疗HBV感染患者的一种成功方法，其中包括核苷类似物拉米夫定[（-）2'-脱氧-3'-硫代胞苷，3TC]。尽管在一些HBV感染患者中已报道对拉米夫定治疗产生耐药性，但HBV中耐药相关突变的模式尚未完全明确。我们报告了一个DNA序列数据库，该数据库包含来自20例有拉米夫定耐药临床表现患者的HBV聚合酶基因的500个碱基对区域。对该数据库的分析揭示了HBV聚合酶酪氨酸、甲硫氨酸、天冬氨酸、天冬氨酸（YMDD）核苷酸结合位点的两种氨基酸替代模式。第一组患者血清中的HBV DNA在第552位残基处表现为缬氨酸替代甲硫氨酸，同时在第528位残基处表现为甲硫氨酸替代亮氨酸。第二组患者仅在第552位有甲硫氨酸被异亮氨酸替代。在瞬时转染细胞试验中，在具有HBV复制能力的质粒中重建这些突变，以确定这些突变对拉米夫定耐药性的功能/相关性。第一组和第二组突变均导致对拉米夫定治疗的敏感性大幅降低（IC50相对于野生型[wt]IC50有>10000倍的变化），强烈表明这些突变与拉米夫定耐药有关。已生成HBV逆转录酶的假设模型，以进一步研究这些突变在拉米夫定耐药中的作用。
