B和C基因型HBsAg+/HBsAb+双阳性患者S区基因的抗原表位及相关基因的突变

doi:10.3969/j.issn.1673-8640.2016.08.015

摘要/Abstract

摘要：

目的探讨B和C基因型的乙型肝炎表面抗原（HBsAg）⁺/乙型肝炎表面抗体（HBsAb）⁺双阳性乙型肝炎患者S区基因抗原表位之间的差异及其与HBsAg⁺/HBsAb⁺双阳性现象之间的关系。方法选取5例HBsAg⁺/HBsAb⁺双阳性样本的51个S区克隆株作为研究对象,对其S区基因克隆测序并进行统计分析。结果 5例样本中C基因型3例,B基因型2例。C基因型的30个克隆株S区氨基酸变异率显著高于B基因型的21个克隆株,且在S区的N端、C端及MHR区均存在差异。C基因型样本的变异位点主要分布在194、68、3位点,B基因型样本的变异位点则集中在40、200、129、5位点。结论不同基因型的HBsAg⁺/HBsAb⁺双阳性乙型肝炎患者在S区内的氨基酸变异存在差异,主要表现为变异位点及频次的不同,提示不同基因型的HBsAg可能具有不同的抗原表位,即只有抗原表位区内的氨基酸序列改变方可导致HBsAg抗原性改变,从而使HBsAg不能被HBsAb中和,易出现HBsAg⁺/HBsAb⁺双阳性现象。

关键词: 乙型肝炎表面抗原, 乙型肝炎表面抗体, 双阳性, 基因型, 基因突变

Abstract:

Objective To investigate the difference between S region gene epitope and gene mutation of hepatitis B surface antigen （HBsAg） and hepatitis B surface antibody （HBsAb） coexistence patients with genotype B and C,and to study the correlation of HBsAg and HBsAb coexistence. Methods A total of 5 HBsAg and HBsAb coexistence patients were enrolled,and 51 S region clones were collected. S regions were amplified and sequenced. Result There were 3 patients with genotype C and 2 patients with genotype B. The amino acid mutation rate in S region of 30 clones with genotype C was higher than that of 21 clones with genotype B,and differences were found in S region N-terminal,C-terminal and major hydrophilic region（MHR）. The mutation loci of clones with genotype C were mainly concentrated in locus 194,68 and 3,while the mutation loci of clones with genotype B were mainly concentrated in locus 40,200,129 and 5. Conclusions There is difference in amino acid mutation in S region among HBsAg and HBsAb coexistence patients（mutation loci and frequencies） between different genotypes,so epitopes with different genotypes are different. Amino acid mutations within epitope region could lead to the antigenicity changes of HBsAg and potential subsequent failure of neutralization by HBsAb,leading to the coexistence of HBsAg and HBsAb.

Key words: Hepatitis B surface antigen, Hepatitis B surface antibody, Coexistence, Genotype, Gene mutation

中图分类号:

R446.62

王珊, 陈伟琴, 王蕾, 王绮华, 董静懿, 吴春燕. B和C基因型HBsAg⁺/HBsAb⁺双阳性患者S区基因的抗原表位及相关基因的突变[J]. 检验医学, 2016, 31(8): 697-702.

WANG Shan, CHEN Weiqin, WANG Lei, WANG Qihua, DONG Jingyi, WU Chunyan. S region gene epitope and gene mutation of HBsAg and HBsAb coexistence patients with genotype B and C[J]. Laboratory Medicine, 2016, 31(8): 697-702.

图/表 4

参考文献 18

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基因分型	S区各区段
基因分型	S区全长（aa1~ 226）	N端（aa1~ 99）	MHR（aa100~ 169）	MHR1（aa100~ 119）	MHR2（aa120~ 123）	MHR3（aa124~ 137）	MHR4（aa138~ 147）	MHR5（aa148~ 169）	C端（aa170~ 226）
C基因型	3.23	3.57	2.14	2.50	-	5.23	2.00	0.30	3.98
B基因型	1.50	1.59	1.22	-	-	3.40	-	1.73	1.67
χ²值	48.99	17.94	17.90	10.66	-	1.363	4.25	6.28	12.75
P值	0.031	<0.001	<0.001	0.001	-	0.243	0.039	0.012	<0.001

基因分型	S区各区段
基因分型	S区全长（aa1~ 226）	N端（aa1~ 99）	MHR（aa100~ 169）	MHR1（aa100~ 119）	MHR2（aa120~ 123）	MHR3（aa124~ 137）	MHR4（aa138~ 147）	MHR5（aa148~ 169）	C端（aa170~ 226）
C基因型	3.23	3.57	2.14	2.50	-	5.23	2.00	0.30	3.98
B基因型	1.50	1.59	1.22	-	-	3.40	-	1.73	1.67
χ²值	48.99	17.94	17.90	10.66	-	1.363	4.25	6.28	12.75
P值	0.031	<0.001	<0.001	0.001	-	0.243	0.039	0.012	<0.001

S区各区段	C基因型		B基因型
S区各区段	变异位点	变异数（变异频次/克隆总数）	变异位点	变异数（变异频次/克隆总数
N端（aa1~99）	T68I S3N C69stop P62L E2G、F8S、G10K、V14G、F19S、R24K、 D33G、N40S、L42P、G44E、P46L、T47K、 W74T/L/stop、L77Q/R、V96A、L98R	29/30 19/30 12/30 9/30 <5/30	N40S A5S L49H G18N/V、W36stop、 S55F、P67L、I82T	11/21 8/21 7/21 <5/21
MHR （aa100~169）	I126S Y100F、Q101K、M103T、V106F、C107Y/R、 L110P、S114A、G119R、T125A/M、 G130K、T131N、M133T、P135S、K141E、 G145R、E164G、W165stop	10/30 <5/30	Q129R Y161F、W163R、 A166G	10/21 <5/21
C端（aa170~226）	A194V W182stop L213I S204R T189I、W191R、P217Q、I218T、F220L/C、 C221Y、W223stop、V224I	30/30 11/30 7/30 6/30 <5/30	F200Y、 M197T、S204N、 N207D、V224A	11/21 <5/21

S区各区段	C基因型		B基因型
S区各区段	变异位点	变异数（变异频次/克隆总数）	变异位点	变异数（变异频次/克隆总数
N端（aa1~99）	T68I S3N C69stop P62L E2G、F8S、G10K、V14G、F19S、R24K、 D33G、N40S、L42P、G44E、P46L、T47K、 W74T/L/stop、L77Q/R、V96A、L98R	29/30 19/30 12/30 9/30 <5/30	N40S A5S L49H G18N/V、W36stop、 S55F、P67L、I82T	11/21 8/21 7/21 <5/21
MHR （aa100~169）	I126S Y100F、Q101K、M103T、V106F、C107Y/R、 L110P、S114A、G119R、T125A/M、 G130K、T131N、M133T、P135S、K141E、 G145R、E164G、W165stop	10/30 <5/30	Q129R Y161F、W163R、 A166G	10/21 <5/21
C端（aa170~226）	A194V W182stop L213I S204R T189I、W191R、P217Q、I218T、F220L/C、 C221Y、W223stop、V224I	30/30 11/30 7/30 6/30 <5/30	F200Y、 M197T、S204N、 N207D、V224A	11/21 <5/21