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目的 研究慢性乙型肝炎患者体内乙型肝炎病毒 (HBV)表面抗原一级结构的多态性。方法 设计特异性引物 ,自 7例慢性乙型肝炎患者血清中扩增S基因全长或全基因组片段 ,TA克隆法克隆到T载体中 ,随机选择克隆测序。结果 共 2 0个克隆被测序。 2 0个克隆全S蛋白的总一致率仅为 3 2 .0 % ,13株全长为 40 1氨基酸残基的克隆氨基酸一致率为 82 .5 %。患者血清中发现2株克隆编码截短型表面抗原中蛋白 ,在前S1或前S2的免疫决定区或可能的肝细胞结合部位均发现缺失突变。结论 慢性乙肝患者体内存有HBV准种群 ,病毒编码的截短型表面抗原中蛋白可为HBV诱导原发性肝癌提供一种途径 ,应加强对HBsAg一级结构多态性的研究。
Objective To study the primary structure of hepatitis B virus (HBV) surface antigen in patients with chronic hepatitis B (HBV). Methods Specific primers were designed and the full length or whole genome of S gene was amplified from sera of 7 patients with chronic hepatitis B. The TA clones were cloned into T vector and cloned and sequenced randomly. A total of 20 clones were sequenced. The overall concordance rate of 20 cloned whole S proteins was only 32.0%, and that of 13 full-length 40 1 amino acid residues was 82.5%. Two of the clones in the sera of patients were found to encode proteins in truncated surface antigens, with deletion mutations found in pre-S1 or pre-S2 immunoreactive areas or possible hepatocyte binding sites. Conclusion HBV quasispecies population exists in chronic hepatitis B patients. The proteins encoded by virus-encoded truncated surface antigen may provide a way for HBV-induced primary hepatocellular carcinoma, and the research on the primary structure polymorphism of HBsAg should be strengthened.