HCV感染后NS5区抗体的动态观察与检测意义

本文报道用ＨＣＶＮＳ５区两段抗原性较好的合成肽研制的ＥＬＩＳＡ试剂盒及ＵＢＩＨＣＶＮＳ５区抗体检测ＥＬＩＳＡ试剂盒观察１４例ＨＣＶ感染者ＮＳ５区抗体的动态变化，证实ＮＳ５区抗体如同ＮＳ４区抗体一样比Ｃ及ＮＳ３区抗体出现晚。ＮＳ５区抗体总体检出率近似于ＮＳ４区抗体；１．５５％的血清为单独ＮＳ５区抗体阳性；存在ＮＳ５区抗体与其他区抗体滴度有互补作用的标本等提示ＮＳ５区抗体仍有一定的诊断价值。采用ＵＢＩＮＳ５区抗体检测试剂盒发现，９５．６５％（２２／２３）ＵＢＩ试剂盒诊断为ＮＳ５区抗体阳性的标本中含ＨＣＶＲＮＡ，６／１４ＨＣｖ感染者用ＵＢＩ试剂盒检出的抗体出现在ＡＬＴ再次异常升高或剧烈升高（高于参考值的３倍以上）前后，４／１４的感染者抗体出现于ＡＬＴ首次升高前后（其余４／１４的感染者未检出抗ＮＳ５抗体），因此ＵＢＩ抗ＨＣＶＮＳ５抗体诊断试剂盒检测的抗体似与疾病的活动有关。     

丙型肝炎病毒（HCV）E2／NS1相对保守区多肽抗原在检？…

目的 研究（ＨＣＶ）Ｅ２／ＮＳ１相对保守区多肽抗原在检测抗－ＨＣＶ中的意义。方法 利用ＨＣＶＥ２／ＮＳ１基因编码的膜区糖蛋白合成Ｅ２／ＮＳ１相对保守区多肽抗原,建立酶免疫试验（ＥＩＡ）,对９６例ＨＣＶ感染者及４０例正常献血员进行ＨＣＶＥ２／ＮＳ１抗体的检测,同时平行检测ＨＣＶＲＮＡ肝炎为１３．５５％,慢性丙型肝炎为２５．０４％,无症状感染者为２．０８％;正常献血员中发现３例抗ＨＣＶＥ２／ＮＳ１抗体     

检测丙型肝炎患者NS5区抗体的临床意义探讨

目的检测慢性丙型肝炎患者和１４例ＨＣＶ原发感染后ＮＳ５抗体长达一年半的动态变化，探讨ＮＳ５抗体的临床意义。方法应用重组ＮＳ５抗原，建立ＥＩＡ方法进行检测。结果慢性丙型肝炎患者抗－ＮＳ５抗体阳性率为６０．４８％，ＨＣＶ感染后一月抗－ＮＳ５抗体阳性率为１６．３５％，三月为７５％。结论抗－ＮＳ５抗体无早期诊断价值。抗－ＮＳ５抗体持续阳性者，血清ＡＬＴ多明显升高，抗－ＮＳ５抗体与肝脏疾病活动性相关。丙型肝炎患者中存在抗－Ｃ、抗－ＮＳ３、抗－ＮＳ４抗体阴性，而抗－ＮＳ５抗体单独阳性，表明检测抗－ＮＳ５抗体具有独特的诊断价值     

输血后丙型肝炎病毒非结构区抗体和丙氨酸转氨酶的动态分析

利用重组的丙型肝炎病毒非结构区（ＨＣＶＮＳ５）抗原建立了酶免疫试验（ＥＩＡ），对２５例输血后丙型肝炎进行了不同区抗体及丙氨酸转氨酶（ＡＬＴ）的动态研究，同时对１５６例慢性丙型肝炎患者血清进行ＨＣＶＲＮＡ和抗－ＮＳ５平行检测，两者符合率为６４．１％。抗－ＮＳ５抗体首次检出时间为３０～５７５天（１８２．９±１６８．５），晚于ＡＬＴ异常和其他区抗体的出现时间。在感染后１，３，６，１２和２４个月后抗－ＮＳ５的阳性率分别为２８％，４０％，５２％，６８％和７６％。抗－ＮＳ５的动态变化类型为四种：一过性阳性、间歇性阳性、持续性阳性和２年内持续阴性     

肝细胞肝癌中丙型肝炎病毒C区、E区、NS3区、NS4区抗原的表达

本文报道研究丙型肝炎病毒抗原在肝细胞肝癌组织内的定位分布情况。以丙型肝炎病毒（ＨＣＶ）的Ｃ、Ｅ、ＮＳ３、ＮＳ４区四种单克隆抗体用免疫组化方法检测了１３９例肝细胞肝癌（ＨＣＣ）的肝脏标本，结果总的阳性率为１５．１％。２１例阳性标本中，Ｃ区单抗检测阳性占８０．９％（１７／２１），Ｅ区占３３．３％（７／２１），ＮＳ３、ＮＳ４区均占５７．１％（１２／２１），表明应用多区段单抗有助于提高ＨＣＶ抗原的检出率。阳性物质主要存在于胞浆中，呈细、粗颗粒及块状，３例出现膜及膜下型，１例核内有阳性反应。ＨＣＶ感染与ＨＣＣ的发生发展有一定的关系。     

首次及重复感染HCV后抗体及HCV RNA的动态观察

本文报道对首次感染ＨＣＶ的１４人与重复输入含ＨＣＶ血的１１位感染者进行长达一年半的动态观察，总结出输入大量含ＨＣＶ血后导致的感染者在自然状态下ＨＣＶ ＲＮＡ及抗体变化的规律。７／８再次输入４００ｍｌ以上含ＨＣＶ血的感染者，其自身存在的高滴度抗体在受血后１～３个月下降０．５～１．０ＯＤ值。首次输出含ＨＣＶ血的感染者中，１１／１４的感染者３个月内ＡＬＴ高于参考值的３倍以上，而再次输入含ＨＣＶ血的患者中     

从四例丙肝患者系列血清标本分析HCV基因的变异

目的 研究丙型肝炎病人系列血清标本的丙型肝炎病毒（ＨＣＶ）基因型变化及ＨＣＶ膜区基因变异和“准种”现象。方法 对４例因献血感染ＨＣＶ病人的系列血标本，用特异性引物ＰＣＲ扩增检测，５’－ＮＣＲ和核心区测序确定ＨＣＶ基因莳工对标本膜区基因进行克隆重，每个标本随机选择５～９个克隆进行测序分析。结果 发现随着时间推移，存在ＨＣＶ基因型的转换现象。在２种ＨＣＶ基因型转换期存在混合感染。所有测定序列均为１ｂ或     

输血后丙型肝炎病毒血症,抗体及转氨酶动态研究

对１０例输血后丙型肝炎进行了病毒血症、抗体及丙氨酸转氨酶（ＡＬＴ）动态研究。用套式ＰＣＲ法检测丙型肝炎病毒（ＨＣＶ）ＲＮＡ，首次检出时间为输血后１５～８７天，平均４０．３±２０．１天，持续或间歇阳性超过１年者７例。抗ＨＣＶＣ１００．Ｎ１４、Ｐ２２和ＳｃＮＳ３／４和５抗体首次阳转时间分别为输血后３３～４３７（１１９．７±１１９．５）天、５２～１６６（７７．９±３５．６）天、３３～１０３（５５．０±２３．８）天和３３～６６（４０．１±１３．５）天，该４种抗体阳转后都持续１年以上。ＡＬＴ首次异常时间为输血后１５～６０天，平均３７．９±１３．９天，异常超过１年者６例。     

多重引物聚合酶链反应扩增丙型肝炎病毒基因及基 …

利用聚合酶链反应（ＰＣＲ）技术对丙型肝炎病毒（ＨＣＶ）的５’－非编码区（５’－ＮＣＲ）、Ｃ及ＮＳ４基因区的３对引物分别及同时扩增，检测８０例抗－ＨＣＶ阳性患者的血清ＨＣＶ ＲＮＡ，并进行了ＨＣＶ基因分型研究。各不同引物所介导的ＰＣＲ检出ＨＣＶ ＲＮＡ的结果为：５’－ＮＣＲ基因区６０％（４８／８０），Ｃ基因区３７％（３０／８０），ＮＳ４基因区３０％（２４／８０）。以上３对引物同时扩增仅４２％（３４／     

丙型肝炎病毒核酸及其编码蛋白在抗-HCV阴性肝组织中的表达

为了了解丙型肝炎病毒（ＨＣＶ）在抗－ＨＣＶ阴性肝组织中的感染情况，以及免疫与分子病理学方法在ＨＣＶ感染诊断中的临床应用价值。我们应用ＨＣＶＲＮＡ的核心区生物素标记探针及ＨＣＶ３’，５’末端非结构基因区（ＮＳ３，ＮＳ５）编码蛋白的单克隆抗体，对６０例血...     

血清中丙型肝炎NS3抗原ELISA检测方法的建立和初步应用

目的 评价血清中丙型肝炎病毒(HCV)游离NS3抗原的酶联免疫吸附(ELISA)检测方法的特异性和灵敏度,初步探讨该方法在临床应用中的意义.方法 对77例正常人血清标本,173例抗-HCV阳性标本和3708例抗-HCV阴性的其他类型肝炎血清标本检测HCV游离NS3抗原;对部分HCV NS3抗原阳性标本进行验证,包括HCV RNA测定、中和试验和免疫斑点试验;对11例患者的25份系列血清标本进行了HCV游离NS3抗原、HCV RNA和HCV抗体的联合检测,并结合临床资料综合分析.结果 3708例抗-HCV阴性的其他类型肝炎血清标本中有48例为HCV NS3抗原阳性,其中3030例单纯乙型肝炎和445例其他类型肝炎血清标本中分别有44例和4例为HCV NS3抗原阳性;173例HCV抗体阳性标本中有42例为HCV NS3抗原阳性;77例正常人血清标本的HCV NS3抗原检测结果均为阴性;15例HCV NS3抗原阳性标本中有9例为HCV RNA阳性;23例HCV NS3抗原阳性标本的中和率和免疫斑点试验的阳性率分别为87.0%和69.6%;25份系列血清标本的检测结果显示其HCV NS3抗原的吸光度值与时间呈负相关,并有2例HCV NS3抗原阳性标本随着血清中HCV NS3抗原的吸光度值下降,其HCV抗体转阳.结论 血清中HCV游离NS3抗原的ELISA检测方法有较好的特异性和敏感度,在发展中国家应用此方法进行HCV感染的早期诊断有一定的临床意义和推广价值.     

Hepatitis C virus infection in dialysis and chronic liver patients: Viraemia dependent anti-E2-antibody response

Cryptic hepatitis C virus (HCV) infection relates to patients infected chronically with HCV that are seronegative but have HCV-RNA. These patients are not identified by the standard serological tests for HCV, which are based on detection of antibodies to core, NS3 and NS5 antigens. They will, therefore, be wrongly diagnosed as non-infected, and are considered as a potential risk for others. Cryptic HCV infection in dialysis units occurs frequently and, due to medical procedures, is a major factor for contracting the virus when unrecognised. This study was conducted in order to assess the humoral immune responses to E2-antigen in sera of patients infected chronically with HCV. Recombinant E2 protein in enzyme linked immunosorbent assay (ELISA) and Western blot (WB) were used to test the occurrence of anti-E2 antibodies in the sera of patients from the liver clinic and of dialysis patients. The presence of E2 antibodies was found to be correlated with the presence of HCV-RNA and with viral load. Antibodies to the E2 protein could be detected in as many as 30% of the sera from dialysis patients with cryptic HCV infection (HCV-RNA only). The results suggest that detection of anti-E2 antibodies may enhance significantly HCV serological standard testing; especially among patients on dialysis, and that antibodies to envelope E2 protein appear to depend on and correlate with the presence of HCV particles.     

A Novel Antigen Detection Immunoassay for Field Diagnosis of Hepatitis C Virus Infection

Abstract

The limitations of dominant methods-based on the detection of anti-HCV antibodies or HCV viremia currently used for the diagnosis of HCV infection enhance efforts to have a rapid, simple, sensitive, and specific alternative diagnostic approach to detect viral antigens. A highly reactive IgG antibody was raised to HCV-NS4 recombinant antigen. The produced antibody showed no cross-reactivity with the other HCV structural and nonstructural recombinant antigens (C1 + 2, C3 + 4, E2/NS1, NS3, NS5). The well established ELISA technique was adapted to detect the new target HCV-NS4 antigen in serum samples. Extremely high agreement was found between the results of ELISA and qualitative detection of HCV-RNA, using a RT-PCR test as a gold standard for the diagnosis of HCV infection. Based on these encouraging results, a novel enzyme immunoassay; dot-ELISA was developed for rapid (?5 min) and simple qualitative detection of the target HCV antigen in serum. The developed method detected the HCV target antigen in 95% of serum samples from HCV infected individuals, with a specificity of 97% using sera of noninfected individuals in comparison with PCR test. The antigen detection method showed high predictive values of positive (99%) and negative (90%). Moreover, the dot-ELISA could detect the HCV target antigen in sera negative for anti-HCV Abs, but positive for HCV-RNA, and in sera of HCV infected individuals with low viremia, as well as those with high viremia, using quantitative RT-PCR. Accordingly, the developed highly sensitive and specific HCV antigen detection method could be applied for mass screening of HCV infection.     

Characterization of mimotopes mimicking an immunodominant conformational epitope on the hepatitis C virus NS3 helicase

The hepatitis C virus (HCV) nonstructural 3 (NS3) protein is composed of an amino terminal protease and a carboxyl terminal RNA helicase. NS3 contains major antigenic epitopes. The antibody response to NS3 appears early in the course of infection and is focused on the helicase region. However, this response cannot be defined by short synthetic peptides indicating the recognition of conformation-dependent epitopes. In this study, we have screened a dodecapeptide library displayed on phage with anti-NS3 mouse monoclonal antibodies (mAbs) that compete with each other and human anti-HCV NS3 positive sera. Two peptides (mimotopes) were selected that appeared to mimic an immunodominant epitope since they were recognized specifically by the different anti-NS3 mAbs of the study and by human sera from HCV infected patients. Homology search between the two mimotopes and the NS3 sequence showed that one of the two peptides shared amino acid similarities with NS3 at residues 1396-1398 on a very accessible loop as visualized on the three-dimensional structure of the helicase domain whereas the other one had two amino acids similar to nearby residues 1376 and 1378. Reproduced as synthetic dodecapeptides, the two mimotopes were recognized specifically by 19 and 22, respectively, out of 49 sera from HCV infected patients. These mimotopes allowed also the detection of anti-NS3 antibodies in sera of HCV patients at the seroconversion stage. These results suggest that the two NS3 mimotopes are potential tools for the diagnosis of HCV infection.     

Evaluation of a multiple peptide assay for typing of antibodies to the hepatitis C virus: Relation to genomic typing by the polymerase chain reaction

A panel of 16 type-specific synthetic peptides corresponding to variable antigenic regions within the hepatitis C virus (HCV) core, nonstruc-tural 4 (NS4), and NS5 proteins was synthesised. The peptide panel was used to develop an enzyme immunoassay (EIA) for the detection of antibodies directed to HCV type 1 (genotypes I/1a and II/1 b), type 2 (genotypes III/2a and IV/2b), and type 3 (genotype V/3). The peptides corresponded to residues 68–81 of the HCV core (types 1,2, and 3), residues 1692–1705 and 1710–1728 of HCV NS4 (types 1 a, 1 b, 2a, 2b, and 3), and residues 2303–2319 of HCV NS5 (types 1a, 1b, 2a, and 2b). The 16-peptide panel was evaluated using human sera from 46 carriers of HCV, which were genotyped in parallel by the polymerase chain reaction (PCR) using primers specific for types I, II, III, IV, and V of HCV core. Of the 46 carriers, 14 (30%) were infected by HCV genotype I, 7 (15%) by genotype II, 16 (35%) by HCV genotype IV, and 6 (13%) by HCV of genotype V. Two carriers had double infections of types I and II, and the HCV strain of one carrier could not be genotyped. Using the serotyping system, 40 (89%) out of the 45 genotyped carriers were found to contain type-specific antibodies corresponding to the genotypes identified by PCR. In 5 of the 23 carriers infected by genotypes I and/or II, antibodies specific for HCV type 1 could not be detected, whereas all 16 carriers infected by genotype IV were serologically typed as type 2. Out of the six carriers infected by HCV of genotype V, all were found to have antibodies of serotype 3, but in most cases together with antibodies to NS5 type 1, indicating sequence homologies between types 1 and 3 of this NS5 region. In the one patient serum where the HCV strain could not be genotyped, a mixture of types 1, 2, and 3 antibodies were found. In conclusion, a serotyping system with a sensitivity and specificity of 89% was developed. It is confirmed that at least three distinct serotypes of antibodies to HCV exist. The major advantage of using four different antigenic regions is that we often obtain high absor-bance values which are easily interpreted, or multiple reactions which confirm each other. © 1995 Wiley-Liss, Inc.     

Hepatitis C virus recombinants are rare even among intravenous drug users

Systematic studies of the circulation of hepatitis C virus (HCV) recombinants in different parts of the world have been initiated only recently, and no detailed information on this subject is available. The aim of the current investigation was to determine the frequency of HCV recombinants in intravenous drug users (IVDU) from two European countries. HCV RNA from serum samples was tested by RT‐PCR with primers derived from the core and NS5B regions with subsequent sequencing and genotype assignment. The 118 samples from Germany (100%) and 45 out of 47 (96%) sera from Russia demonstrated concordant genotyping results. In the two genotype discrepant sera from Russia 2k/1b recombinants were identified. In order to test the hypothesis that the individuals from the IVDU group might be multiply exposed to various genotypes, 145 out of 165 genotyped serum samples, which were found to be positive for anti‐NS4 antibodies, were serotyped with the Murex HCV serotyping kit that is based on detection of antibodies to type‐specific peptides derived from the NS4 proteins of different HCV genotypes. Discrepancy in genotype and serotype attributions was observed in 11% cases. Retesting of 99 type 1a or 3a samples with a set of type‐ and subtype‐specific primers revealed the presence of a mixed infection only in one case (1a/3a). Thus, the cases of the mixed infection with different HCV genotypes as well as the recombinant forms of HCV are very rare even in such a highly exposed group as IVDU. J. Med. Virol. 82:232–238, 2010. © 2009 Wiley‐Liss, Inc.     

A novel antigen detection immunoassay for field diagnosis of hepatitis C virus infection

The limitations of dominant methods-based on the detection of anti-HCV antibodies or HCV viremia currently used for the diagnosis of HCV infection enhance efforts to have a rapid, simple, sensitive, and specific alternative diagnostic approach to detect viral antigens. A highly reactive IgG antibody was raised to HCV-NS4 recombinant antigen. The produced antibody showed no cross-reactivity with the other HCV structural and nonstructural recombinant antigens (C1 + 2, C3 + 4, E2/NS1, NS3, NS5). The well established ELISA technique was adapted to detect the new target HCV-NS4 antigen in serum samples. Extremely high agreement was found between the results of ELISA and qualitative detection of HCV-RNA, using a RT-PCR test as a gold standard for the diagnosis of HCV infection. Based on these encouraging results, a novel enzyme immunoassay; dot-ELISA was developed for rapid (approximately 5 min) and simple qualitative detection of the target HCV antigen in serum. The developed method detected the HCV target antigen in 95% of serum samples from HCV infected individuals, with a specificity of 97% using sera of noninfected individuals in comparison with PCR test. The antigen detection method showed high predictive values of positive (99%) and negative (90%). Moreover, the dot-ELISA could detect the HCV target antigen in sera negative for anti-HCV Abs, but positive for HCV-RNA, and in sera of HCV infected individuals with low viremia, as well as those with high viremia, using quantitative RT-PCR. Accordingly, the developed highly sensitive and specific HCV antigen detection method could be applied for mass screening of HCV infection.     

Antigenic regions within the hepatitis C virus envelope 1 and non-structural proteins: identification of an IgG3-restricted recognition site within the envelope 1 protein

Antibody binding to antigenic regions of hepatitis C virus (HCV) envelope 1 (El; residues 183–380), E2/non-structural (NS) 1 (residues 380–437), NS1 (residues 643–690), and NS4(1684–1751) proteins were assayed for 50 sera with antibodies to HCV (anti-HCV) and for 46 sera without anti-HCV. Thirty-four peptides. 18 residues long with an eight-amino acid overIap within each HCV region, were synthesized and tested with all 96 sera. Within the E region 183–380, the major binding site was located to residues 203–220, and was recognized by eight sera. Within the E2/NS1 region 380–437, the peptide covering residues 410–427 was recognized by two sera, and within the NSl region 643–690, peptides covering residues 663–690 were recognized by four sera. Within the NS4 region 1684–1751, 27 sera were reactive to one or more of the NS4 peptides, and 21 out of these were reactive with peptide 1694–1711. One part of the major binding site could be located to residues 1701–1704, with the sequence Leu-Tyr-Arg-Glu. The IgGl, IgG3 and IgG4 subcIasses were reactive with the five antigenic regions of HCV core, residues 1–18, 11–28, 21–38, 51–68 and 101–118. Reactivity to the major envelope site consisted almost exclusively of IgG3, and reactivity to the major site of NS4 consisted only of IgG1. Thus, a non-restricted IgG response to linear HCV-encoded binding sites was found to the core protein, whereas IgG subcIass-restricted linear binding sites were found within the El protein, and within the NS4 protein.     

Antigenic structure of the complete nonstructural (NS) 2 and 5 proteins of hepatitis C virus (HCV): anti-HCV NS2 and NS5 antibody reactivities in relation to HCV serotype, presence of HCV RNA, and acute HCV infection.

Antigenic regions within the nonstructural (NS) 2 and 5 proteins of hepatitis C virus (HCV) were identified and characterized by the use of 127 overlapping synthetic peptides and a serum panel consisting of 167 human serum samples from persons with antibodies to HCV. Initially, 20 anti-HCV-positive serum samples were used to screen the peptides covering the complete NS2 and NS5 proteins. Among the 27 overlapping peptides spanning the NS2 protein of HCV, only the peptide covering residues 960 to 975 was recognized by human sera. Within the 100 peptides covering the NS5 protein, major linear antigenic regions were located at residues 2284 to 2329 within the putative NS5a and at residues 2584 to 2599 and 2944 to 2959 within the putative NS5b. Additional minor linear antigenic regions were also identified within the NS5. The sequence of the antigenic region of the NS2 protein is, unlike most parts of the NS2 protein, highly conserved among the described types of HCV, whereas the sequence of the major antigenic region of NS5 shows variability among HCV types. The recognition of a peptide corresponding to a part of the major region of NS5 was found to be dependent on HCV type. In 129 anti-HCV-positive serum samples, the prevalence of antibodies to the NS2 protein was found to be 23% among HCV RNA-positive sera and 10% among HCV RNA-negative sera. In the same samples, reactivity to the major linear antigenic regions of HCV NS5 was found in 68% of the HCV RNA-positive sera and 67% of the HCV RNA-negative sera. Of 18 serum samples from five patients with acute HCV infections, and who seroconverted with respect to anti-HCV, 4 were found to be reactive to one or more of the 100 NS5 peptides and in three serum samples the NS5 reactivities were found to shorten the time for serodiagnosis of cross-reactive with a region form residues 2584 to 2599 of NS5, which has 67% homology with a six-residue sequence of NS2. In conclusion, in this study we have identified and evaluated the potential use of synthetic peptides corresponding to linear antigenic regions of the NS2 and NS5 proteins.