氨基酸取代在乙型肝炎病毒表面蛋白对病毒粒子分泌，抗原

StephenW

Effects of amino acid substitutions in hepatitis B virus surface protein on virion secretion, antigenicity, HBsAg and viral DNA
Kuan-hui Xiang
, Eleftherios Michailidis
, Hai Ding
, Ya-qin Peng
, Ming-ze Su
, Yao Li
, Xue-en Liu
, Viet Loan Dao Thi
, Xian-fang Wu
, William M. Schneider
, Charles M. Rice
, Hui Zhuang correspondencePress enter key for correspondence informationemailPress enter key to Email the author
, Tong Li correspondencePress enter key for correspondence informationemailPress enter key to Email the author


DOI:            http://dx.doi.org/10.1016/j.jhep.2016.09.005 |





Background & AimsAs important virological markers, serum hepatitis B surface antigen (HBsAg) and hepatitis B virus (HBV) DNA levels show large fluctuations among chronic hepatitis B patients. The aim of this study was to reveal the potential impact and mechanisms of amino acid substitutions in small hepatitis B surface proteins (SHBs) on serum HBsAg and HBV DNA levels.
MethodsSerum samples from 230 untreated chronic hepatitis B patients with genotype C HBV were analyzed in terms of HBV DNA levels, serological markers of HBV infection and SHBs sequences. In vitro functional analysis of the identified SHBs mutants was performed.
ResultsAmong 230 SHBs sequences, there were 39 (16.96%) sequences with no mutation detected (wild-type) and 191 (83.04%) with single or multiple mutations. SHBs consist of 226 amino acids, of which 104 (46.02%) had mutations in our study. Some mutations (e.g., sE2G, sL21S, sR24K, sT47A/K, sC69stop (sC69∗), sL95W, sL98V, and sG145R) negatively correlated with serum HBsAg levels. HBsAg and HBV DNA levels from this group of patients had a positive correlation (r = 0.61, p <0.001). In vitro analysis showed that these mutations reduced extracellular HBsAg and HBV DNA levels by restricting virion secretion and antibody binding capacity. Virion secretion could be rescued for sE2G, sC69∗, and sG145R by co-expression of wild-type HBsAg.
ConclusionThe serum HBsAg levels were lower in untreated CHB patients with novel SHBs mutations outside the major antigenic region than those without mutations. Underlying mechanisms include impairment of virion secretion and lower binding affinity to antibodies used for HBsAg measurements.
Lay summaryThe hepatitis B surface antigen (HBsAg) is a major viral protein of the hepatitis B virus (HBV) secreted into patient blood serum and its quantification value serves as an important marker for the evaluation of chronic HBV infection and antiviral response. We found a few new amino acid substitutions in HBsAg associated with lower serum HBsAg and HBV DNA levels. These different substitutions might impair virion secretion, change the ability of HBsAg to bind to antibodies, or impact HBV replication. These could all result in decreased detectable levels of serum HBsAg. The factors affecting circulating HBsAg level and HBsAg detection are varied and caution is needed when interpreting clinical significance of serum HBsAg levels.
Clinical trial number: NCT01088009.

Keywords:                HBV, HBsAg mutation, Virion secretion, Antigenicity, ‘a’ determinant, Hepatitis B surface antigens, Amino acid substitution, DNA, Viral, Membrane proteins

StephenW

氨基酸取代在乙型肝炎病毒表面蛋白对病毒粒子分泌，抗原性，HBsAg和病毒DNA的影响
甘惠祥
，Eleftherios Michailidis
，海定
，赵亚琴
，Ming-ze Su
，姚丽
，Xue-en Liu
，越南道
，西安吴
，William M. Schneider
，Charles M. Rice
，回传通信按回车键进入通信信息邮件按回车键发电子邮件给作者
，通利通信按确认键输入通信信息
文章的评分为17分
DOI：http://dx.doi.org/10.1016/j.jhep.2016.09.005 |

图缩略图fx1
背景与目的

作为重要的病毒学标记物，血清乙型肝炎表面抗原（HBsAg）和乙型肝炎病毒（HBV）DNA水平在慢性乙型肝炎患者中显示出大的波动。本研究的目的是揭示氨基酸替代在小乙型肝炎表面蛋白（SHBs）对血清HBsAg和HBV DNA水平的潜在影响和机制。
方法

根据HBV DNA水平，HBV感染的血清学标志物和SHBs序列分析来自230位未治疗的基因型C HBV的慢性乙型肝炎患者的血清样品。进行了鉴定的SHBs突变体的体外功能分析。
结果

在230个SHB序列中，有39个（16.96％）没有检测到突变的序列（野生型）和191个（83.04％）具有单个或多个突变。 SHB由226个氨基酸组成，其中104个（46.02％）在我们的研究中具有突变。一些突变（例如sE2G，sL21S，sR24K，sT47A / K，sC69stop（sC69 *），sL95W，sL98V和sG145R）与血清HBsAg水平呈负相关。来自这组患者的HBsAg和HBV DNA水平具有正相关（r = 0.61，p <0.001）。体外分析显示这些突变通过限制病毒粒子分泌和抗体结合能力来减少细胞外HBsAg和HBV DNA水平。病毒粒子分泌可以通过野生型HBsAg的共表达来拯救sE2G，sC69 *和sG145R。
结论

在未治疗的CHB患者中，在主要抗原区域之外的新型SHB突变的血清HBsAg水平低于没有突变的那些。基础机制包括病毒粒子分泌的损伤和对用于HBsAg测量的抗体的较低的结合亲和力。
放置摘要

乙型肝炎表面抗原（HBsAg）是分泌到患者血清中的乙型肝炎病毒（HBV）的主要病毒蛋白，其定量值作为评价慢性HBV感染和抗病毒反应的重要标志物。我们在HBsAg中发现了一些新的氨基酸取代与更低的血清HBsAg和HBV DNA水平相关。这些不同的取代可能损害病毒体分泌，改变HBsAg结合抗体的能力或影响HBV复制。这些都可导致血清HBsAg的可检测水平降低。影响循环HBsAg水平和HBsAg检测的因素是多样的，当解释血清HBsAg水平的临床意义时需要谨慎。

临床试验编号：NCT01088009。
关键词：
HBV，HBsAg突变，病毒分泌，抗原性，“a”决定簇，乙型肝炎表面抗原，氨基酸替代，DNA，病毒，膜蛋白