HBsAb阳性隐匿性乙型肝炎病毒T细胞及B细胞表位变异分析
Mutation analysis of T-cell and B-cell epitopes derived from HBV PreS-S protein in HBsAb positive occult hepatitis B virus infection
郭燕 1景媛媛 1李锦 1巩晗实 1段勇 1李燕 2张文娟1
作者信息
- 1. 陕西省血液中心,西安 710061
- 2. 罗氏诊断-中国地区,上海 201100
- 折叠
摘要
目的 分析隐匿性乙型肝炎病毒(occult hepatitis B virus,OHBV)PreS-S基因T、B细胞表位变异情况,探讨隐匿性乙型肝炎病毒感染(occult hepatitis B virus infection,OBI)及HBsAb+OBI发生机制.方法 利用巢式聚合酶链反应(nested PCR)扩增OBI样品PreS-S区并测序,确定基因型.生物信息学分析HBsAb+/HBsAb-以及不同基因型OBI毒株PreS-S基因T、B细胞表位变异情况,分析高频T细胞突变表位突变前后与人类白细胞抗原(human leukocyte antigen,HLA)亲和力变化以及高频B细胞突变表位突变后抗原特性的改变.结果 85份OBI样品成功扩增出PreS-S基因21 份,其中 HBsAb+OBIB 4 份,HBsAb-OBIB 6 份,HBsAb+OBIC 6 份,HBsAb-OBIC 5 份.OBI 毒株 PreS-S区突变率高于野毒株,差异有显著的统计学意义(OBIB vs.WTB:2.64％:0.66％,P＜0.001;OBIC vs.WTC:3.67％:1.19％,P＜0.001).OBI毒株蛋白免疫区突变率大于非蛋白免疫区,差异有显著的统计学意义(OBIB:3.57％:1.86％,P=0.005;OBIC:4.78％:2.65％,P=0.001).OBIC 毒株蛋白免疫区及非蛋白免疫区突变率均大于OBIB毒株,差异无统计学意义(蛋白免疫区:4.78％:3.57％,P=0.107;非蛋白免疫区:2.65％:1.86％,P=0.142).HBsAb-OBI毒株T、B细胞表位突变率高于HBsAb+OBI毒株,差异无统计学意义(HBsAb-OBIB vs.HBsAb+OBIB:4.17:3.01,P=0.303;HBsAb-OBIC vs.HBsAb+OBIC:5.65:4.26,P=0.207).4 个 T 细胞表位高频突变(T47A/K、S174N、L175S、V177A)以及 3 个 B细胞表位高频突变(G73S、K122R、I126M/T)的亲和力分析和抗原性分析显示多数T细胞表位突变前后与HLA分子亲和力变化不大,B细胞表位免疫原性变化不明显,某些位点突变后亲水性、表面可及性甚至优于野生毒株.结论 OBI毒株PreS-S区突变率显著高于野毒株;OBI毒株蛋白免疫区突变率显著高于非蛋白免疫区;OBIC变异活跃程度大于OBIB;各点突变可能在病毒复制过程中随机发生,未发现HBsAb压力或依赖性;PreS-S区关键位点突变或多表位共同突变可能在OBI形成中发挥重要作用.
Abstract
Objective To analyze the mutation of T-cell and B-cell epitopes derived from HBV PreS-S protein in occult hepatitis B virus(OHBV)and investigate the biological mechanisms of occult hepatitis B virus infection(OBI)and HBsAb positive OBI.Methods The PreS-S region of OBI samples were amplified by nested PCR,the products were sequenced and HBV genotypes were determined.The mutations of T-cell and B-cell epitopes derived from HBV PreS-S protein were analyzed and compared among groups of HBV genotypes and the presence of HBsAb.The affinity of the high frequency of T-cell epitope substitutions were analyzed by SYF PEITHI,the changes of antigenic characteristics of high frequency of B-cell epitope substitutions were analyzed by Ab Designer,Expasy ProtParam tool,Epitope Prediction and Analysis Tools.Results The PreS-S region of HBV was amplified in 21 samples,including 4 HBsAb+OBIB,6 HBsAb-OBIB,6 HBsAb+OBIC,5 HBsAb-OBIC.The mutation rates in PreS-S region of OBI were significantly higher than wild type HBV strains(OBIB vs.WTB:2.64％:0.66％,P＜0.001;OBIC vs.WTC:3.67％:1.19％,P＜0.001).The mutation rates of the immunoreactive area were significantly higher than non-immunoreactive area in OBI(OBIB:3.57％:1.86％,P=0.005;OBIC:4.78％:2.65％,P＜0.001).The mutation rates of the immunoreactive and non-immunoreactive area in OBIC were higher than OBIB,but there was no statistically significant difference(immunoreactive area:4.78％:3.57％,P=0.107;non-immunoreactive area:2.65％:1.86％,P=0.142).The mutation rates of T-cell and B-cell epitopes of HBsAb-OBI were higher than HBsAb+OBI,although there was no significant difference(HBsAb-OBIB vs.HBsAb+OBIB:4.17:3.01,P=0.303;HBsAb-OBIC vs.HBsAb+OBIC:5.65:4.26,P=0.207).The affinity analysis of 4 high frequency T-cell epitope substitutions,including T47A/K,S174N,L175S,V177A,showed that the changes of affinity of most mutation sites were not obvious;the antigenicity analysis of 3 high frequency B-cell epitope substitutions,including G73S,K122R,I126M/T,did not show noticeable changes and the hydrophilicity,surface accessibility of some mutation sites were even better than wild strain.Conclusions The mutation rates in PreS-S region of OBI were significantly higher than wild type HBV strains.The mutation rates of the immunoreactive area were higher than non-immunoreactive area in OBI.The variant activity of OBIC was higher than OBIB.The mutations of OBI might occur randomly and were not selected by antibody pressure.Single epitope and multi-epitopes combinational mutations might be a reason for OBI.
关键词
隐匿性乙肝/PreS-S区/细胞表位变异Key words
Occult hepatitis B virus infection/PreS-S region/Cell epitope mutation引用本文复制引用
出版年
2024
NETL
NSTL
万方数据