Functional analysis of 'a' determinant mutations associated with occult HBV in HIV-positive South Africans.
Functional analysis of 'a' determinant mutations associated with occult HBV in HIV-positive South Africans.
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与 HIV 阳性南非人隐匿性 HBV 相关的“a”决定突变的功能分析。
DOI：
10.1099/jgv.0.000469
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
Blackard,JasonT
中科院分区：
文献类型：
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作者：
Powell,EleanorA;Boyce,CeejayL;Gededzha,MaemuP;Selabe,SelokelaG;Mphahlele,MJeffrey;Blackard,JasonT
隐匿性B型肝炎的定义是存在B型肝炎病毒（HBV）DNA，但不存在B型肝炎表面抗原（HBsAg）。隐匿性HBV与肝细胞癌的发生、免疫抑制期间的再激活和病毒传播有关。病毒突变对隐匿性HBV表型有重要作用。乙型肝炎表面抗原“a”决定簇中的突变特别令人感兴趣，因为这些突变与免疫逃逸、疫苗逃逸和诊断失败有关。我们研究了在HIV阳性的南非人群中发现的某些HBV相关隐性突变对体外HBsAg生成的影响。将突变插入到两个不同的慢性HBV骨架中，并转染到肝细胞衍生的细胞系中。通过酶联免疫吸附试验（ELISA）定量HBsAg水平，同时使用HA标记的HBsAg表达系统确定突变型HBsAg的可检测性。在分析的7种突变中，4种（S132 P、C138 Y、N146 D和C147 Y）导致一种病毒背景中HBsAg表达降低，但在第二种病毒背景中不降低。与HA-标签相比，一个突变（N146 D）导致检测到的HBsAg减少，表明该突变损害了ELISA检测HBsAg的能力。通过在单一病毒背景下检测突变的影响，无法充分确定隐匿性HBV的隐匿性相关突变对HBeAg阴性表型的贡献，需要对这些突变进行严格分析。
Occult hepatitis B is defined by the presence of hepatitis B virus (HBV) DNA in the absence of hepatitis B surface antigen (HBsAg). Occult HBV is associated with the development of hepatocellular carcinoma, reactivation during immune suppression, and virus transmission. Viral mutations contribute significantly to the occult HBV phenotype. Mutations in the ‘a’ determinant of HBsAg are of particular interest, as these mutations are associated with immune escape, vaccine escape and diagnostic failure. We examined the effects of selected occult HBV-associated mutations identified in a population of HIV-positive South Africans on HBsAg production in vitro. Mutations were inserted into two different chronic HBV backbones and transfected into a hepatocyte-derived cell line. HBsAg levels were quantified by enzyme-linked immunosorbent assay (ELISA), while the detectability of mutant HBsAg was determined using an HA-tagged HBsAg expression system. Of the seven mutations analysed, four (S132P, C138Y, N146D and C147Y) resulted in decreased HBsAg expression in one viral background but not in the second viral background. One mutation (N146D) led to a decrease in HBsAg detected as compared to HA-tag, indicating that this mutation compromises the ability of the ELISA to detect HBsAg. The contribution of occult-associated mutations to the HBsAg-negative phenotype of occult HBV cannot be determined adequately by testing the effect of the mutation in a single viral background, and rigorous analysis of these mutations is required.