摘要
目的探讨乙肝疫苗免疫献血者人群中HBV感染的分子生物学特性及其HBsAg＋／抗．HBs＋发生机制。方法从13504（人）份无偿献血者标本中，收集HBsAg＋／HBVDNA＋者58例，应用巢式．聚合酶链反应技术获得其中35例Pre—S／S基因片段并测序、基因分型；采用荧光定量聚合酶链反应技术测定58例阳性标本的病毒载量，通过咨询随访，确认其中的接种乙肝疫苗后HBsAg＋／抗-HBs＋／抗-HBc＋者，并与对应基因型的HBsAg＋／抗。HBs-／抗HBc＋毒株Pre—S／S序列比对，分析其变异特征。结果深圳地区无偿献血者HBV检出率为0．43％（58／13504），HBV感染率约为1．90％（26／13707）；35例Pre—S／S区扩增成功的标本基因型B、C构成比分别为42．86％（15／35）、57．14％（20／35），其中5例HBsAg＋／抗．HBs＋／抗-HBc＋标本均为基因曰型，抗-HBs滴度（10．45—88．76）（中位数21．54）mlU／mL，病毒载量为（3．8～5．5）X10’（中位数6．7x10。）IU／mL。HBsAg＋／抗一HBs＋组除了Pre—S1基因区，Pre．S／S、Pre．S2、S、MHRl、MHR2、a抗原决定簇基因的氨基酸置换率均明显高于HBsAg＋／抗HBs一组各区（P〈0．05），以主要亲水1区（MHRl）和Pre．s2区的氨基酸变异率最高（3．11％、4．36％），MHRl区出现少见的N40S、P62L变异，在主要亲水2区（MHR2）有60％（3／5）标本为高度保守，20％（1／5）标本在整个Pre-SIS区没发生变异。未发现a抗原决定簇常见G145R变异。结论接种乙肝疫苗后出现HBsAg＋／抗-HBs＋的机制与Pre-S／S区变异，特别是MHRl、Pre．s2区变异增多有重要关联，基因B型的HBVDNA可能在乙肝疫苗免疫压力下更易发生变异而导致抗-HBs与HBsAg不能中和。
Objective To investigate the molecular characteristics of HBV infection and the occurrence mechanism of HB- sAg ＋/anti-HBs ＋ from the hepatitis B vaccinated blood donors in Shenzhen area. Methods A total of 58 HBsAg ＋/HBV DNA ＋ serum samples collected from 13 504 donors were quantified by QPCR,35 of 58 samples were amplified the Pre-S/S fragment successfully by the nested PCR and determined the genotype. Through the follow-up of consulting,5-58 were confirmed as vaccinated blood donors with HBsAg ＋/anti-HBs ＋/anti-HBc ＋, and compared to consensus sequences of Pre-S/S of HBsAg ＋/anti-HBs-/anti-HBc ＋ strains with similar genotype. Results The detection rate and infection rate of HBV in Shenzhen donors was 0.43% （58/13 504） and 1.90（26/13 707）% ,respectively. Among 35/58 Pre-S/S positive samples,HBV genotypes B and C were dominant（42.86% and 57.14% ,respectively）. All of 5 HBsAg ＋/anti-HBs ＋/anti-HBc ＋ samples were geno- type B with low anti-HBs titre, ranging between 10.45 ~ 88.76 mIU/mL（ median ：21.54 IU/mL）. In the Pre-S/S, Pre-S2, S, MHR1 ,MHR2 and a determinant regions ,the substitutions of amino acid mutations in HBsAg ＋/anti-HBs ＋ samples were sig- nificant popular than those HBsAg ＋/anti-HBs- samples （P 〈 0. 05 ）, except Pre-Sl region. Most amino acid mutations occurred in major hydrophilic region 1 （ MHR1 ） and Pre-S2 regions （3.11%, 4.36% ）, rare mutations of N40S, P62L were found in MHR1. In Major hydrophilic region 2 （MHR2） and Pre-S/S regions, we found no mutations in 60% （3/5） and 20% （ 1/5 ） samples,respectively. Besides,the popular mutation G145R was not found in adeterminant regions. Conclusion The mutations in Pre-S/S region,especially in MHR1 and Pre-S2 regions play an important rote in the occurrence of HBsAg ＋/anti-HBs ＋ in vaccinated donors. More mutations occurred in HBV DNA of genotype B,which results in anti-HBs failed neutralizing with HB- sAg under HBV vaccine pressure.
出处
《中国输血杂志》
CAS
CSCD
北大核心
2013年第10期976-981,共6页
Chinese Journal of Blood Transfusion
基金
广东省医学科学基金(A2012580)
