HGV／GBV—C与HCV混合感染者HGV／GBV—C复制中间体的研究

目的 关于ＨＧＶ／ＢＧＶ－Ｃ组织亲和性的研究尚无结论性资料。我们研究了ＨＧＶ／ＧＢＶ－Ｃ与ＨＣＶ混合感染者ＰＢＭＣ和肝脏中ＨＧＶ／ＧＢＶ－Ｃ复制中间体（负链ＲＮＡ）的存在状况。方法 应用逆转录－巢式ＰＣＲ技术,检测了３２例肝炎患者ＨＧＶ／ＧＢＶ－Ｃ和ＨＶＣ正、负链ＲＮＡ。结果 有２６例ＨＧＶ／ＧＢＶ－Ｃ与ＨＣＶ混合感染者ＰＢＭＣ和肝脏中均未检测到ＨＧＶ／ＧＢＶ－Ｃ负链ＲＮＡ;而在９份ＰＢＭＣ和１５     

Proteomics computational analyses suggest that hepatitis C virus E1 and pestivirus E2 envelope glycoproteins are truncated class II fusion proteins

Class II fusion proteins encoded by tick-borne encephalitis virus (TBEV), dengue virus, and Semliki Forest virus have a fusion peptide located at the end of a rod-like molecule comprised of three antiparallel beta sheet domains. Proteomics computational analyses suggest that hepatitis C virus (HCV) envelope glycoprotein E1 and pestivirus envelope glycoprotein E2 are truncated class II fusion proteins. Similarities were also detected between the receptor-binding portion of TBEV E and HCV E2, and between TBEV small membrane protein precursor prM and pestivirus E1. The proposed models of Flaviviridae envelope proteins can facilitate drug and vaccine development.     

Evaluation of the clinical usefulness of COBAS AMPLICOR HCV MONITOR assay (ver2.0): Comparison with AMPLICOR HCV MONITOR assay (ver1.0) and HCV core protein level

The quantitation of serum levels of hepatitis C virus (HCV) RNA in chronic hepatitis C has been regarded as one of the most important indicators for the outcome of interferon (IFN) therapy. The AMPLICOR HCV MONITOR version 1.0 (AMPLICOR v1.0) assay is widely used for the evaluation of the HCV level. A new generation assay called the COBAS AMPLICOR HCV MONITOR version 2.0 (COBAS v2.0) assay, which is semiautomated and modified to amplify all genotypes equally, has been developed. The aim of this study was to evaluate the clinical relevance of the COBAS v2.0 assay in comparison with the AMPLICOR v1.0 assay and HCV core protein assay in patients with chronic hepatitis C before IFN therapy. HCV RNA was detectable in 230 cases (97.5%) and undetectable in 6 cases (2.5%) by the COBAS v2.0 assay. The RNA levels measured by the AMPLICOR v1.0 assay correlated significantly with those measured by the COBAS v2.0 assay, and the sensitivity of the new version 2.0 assay was better than that of version 1.0, especially in serotype 2. In relation to the outcome of IFN therapy, HCV RNA levels from virologically sustained responders by the AMPLICOR v1.0 assay were 82.3 +/- 22.9 kcopies/ml in serotype 1 and 36.9 +/- 13.4 kcopies/ml in serotype 2, and those from virologically nonsustained responders were 525.2 +/- 48.6 kcopies/ml in serotype 1 and 76.7 +/- 19.5 kcopies/ml in serotype 2.The rates of sustained response to <100 kcopies/ml were 34/63 (54.0%) in serotype 1 and 24/48 (50.0%) in serotype 2. A statistically significant virological response was seen in serotype 1 (P < 0.0001), but not in serotype 2. In contrast, the levels in virologically sustained responders by the COBAS v2.0 assay were 88.2 +/- 20.5 KIU/ml in serotype 1 and 136.8 +/- 40.1 KIU/ml in serotype 2, and those in virologically nonsustained responders were 608.8 +/- 48.4 KIU/ml in serotype 1 and 328.3 +/- 62.8 KIU/ml in serotype 2. The rates of sustained response to <100 KIU/ml were 33/60 (55.0%) in serotype 1 and 21/35 (60.0%) in serotype 2. Statistical significance in virological response was seen in both serotype 1 (P < 0.0001) and serotype 2 (P < 0.05). Although the sensitivity of the HCV core protein assay was lower than that with the COBAS v2.0 assay, the HCV core protein levels also correlated well with the results of the COBAS v2.0 assay. The HCV core protein levels of virologically sustained responders were 37.6 +/- 12.0 pg/ml in serotype 1, 81.3 +/- 37.0 pg/ml in serotype 2, and those of virologically nonsustained responders were 289.9 +/- 23.5 pg/ml in serotype 1, 191.4 +/- 32.1 pg/ml in serotype 2. This assay could predict the outcome of IFN therapy in both serotype 1 (P < 0.0001) and serotype 2 (P < 0.05). Thus, both the COBAS v2.0 assay and the HCV core protein assay showed that the viral load was an indicator of virologically sustained response in serotype 2 and in serotype 1.     

HBV与HCV融合DNA疫苗的构建及其体液免疫应答

目的 构建含乙型肝炎病毒（HBV）表面抗原基因（S区基因）与丙型肝炎病毒（HCV）核心抗原基因（C区基因）的嵌合真核表达载体,观察preS1和preS2基因对HBV表面抗原及HCV核心抗原体液免疫的影响。方法 用PCR方法,分别扩增HBV S区基因和HCV C区基因。将S区基因克隆入真核表达载体pcDNA3.1,酶切鉴定后,大量提取质粒并免疫Balb/c小鼠,用ELISA法检测抗HBs和抗HCV抗体。结果 成功地扩增出目的基因片段,克隆后酶切鉴定结果正确,序列分析与文献报告相一致。免疫后检测到抗HBs和抗HCV抗体。preS1与preS2基因对构建的融合DNA疫苗的体液免疫应答有一定的抑制作用。抗HBs抗体的产生低于只含S基因的真核表达载体;preS1基因对抗HCV抗体的产生具有抑制作用,而preS2无影响。结论 不同长度的HBV S区基因可影响抗HBs和抗HCV抗体的产生。     

Glycoproteins of representative paramyxoviruses: isolation and antigenic analysis using a zwitterionic surfactant.

A new method for the isolation of biologically active envelope antigens from paramyxo- and myxoviruses was developed using a zwitterionic detergent Empigen BB. Essentially complete recovery of hemagglutinin and sialidase from representative paramyxoviruses (PMY, NDV, and Sendai virus) and influenza virus X7 was achieved. The glycoproteins (HN and F) of PMY were purified in a DEAE-Bio-Gel A column equilibrated with bicarbonate buffer containing Empigen, Polyacrylamide gel electrophoresis analysis of pooled HN fractions revealed one band, indicating that it is a common glycoprotein. Gels of pooled F-enriched fractions revealed three bands corresponding to LGP, HN, and F. Gels of PMY virus revealed six polypeptides, and they have been tentatively designated L, LGP, HN, F, NP, and M. LGP, a large glycoprotein, was not detected in gels of NDV and Sendai virus. It has been proposed that LGP may consist of a complex of F. Antiserum was prepared against purified HN and it was found to be monospecific. The antiserum inhibited both hemagglutination and enzyme activities of PMY, which is in support of the hemagglutinin and sialidase of PMY being associated with a common glycoprotein. By enzyme inhibition analysis of PMY, NDV, and Sendai virus, it was shown that the enzymes of these viruses are antigenically distinct. The methods described for the isolation and purification of PMY glycoproteins may be useful for the preparation of myxo- and paramyxovirus subunit vaccines.     

丙型肝炎患者血清抗丙型肝炎病毒抗体IgM及HCVRNA检测结果的比较

用酶联免疫吸附试验（ＥＬＩＳＡ）对住院病人抗丙型肝炎病毒抗体（抗－ＨＣＶ）阳性血清标本进行抗－ＨＣＶＩｇＭ的检测，并与ＨＣＶＲＮＡ检测结果比较。结果表明，ＨＣＶＲＮＡ阳性、抗－ＨＣＶ阳性，ＨＣＶＲＮＡ阳性、抗－ＨＣＶ阴性及ＨＣＶＲＮＡ阴性、抗－ＨＣＶ阳性三种类型中均有抗－ＨＣＶＩｇＭ阳性者。结果还表明ＨＣＶＲＮＡ阳性病例的抗－ＨＣＶＩｇＭ阳性率明显高于ＨＣＶＲＮＡ阴性的病例（Ｐ＜０．０５），在临床诊断上ＨＣＶＲＮＡ阳性与阴性病例的肝病大多数为急性肝炎（ＡＨ）和慢性活动性肝炎（ＣＡＨ），ＨＣＶＲＮＡ阳性与阴性比较，各类肝病的病例数无明显差别。     

Complement component C3b binds directly to purified glycoprotein C of herpes simplex virus types 1 and 2

Cells infected with herpes simplex virus type 1 (HSV-1), but not HSV-2, express on their surfaces a receptor for the complement component C3b. Receptor activity is markedly enhanced by treatment of the infected cells with neuraminidase. Employing a direct binding assay, consisting of purified HSV glycoproteins immobilized on nitrocellulose and iodinated C3b as a probe, we found that C3b binds directly to gC-1, as well as to gC-2, but not to gB or gD from either serotype. C3b binding was enhanced by treatment of gC-1 or gC-2 with neuraminidase. Endo F or endo H treatment of gC-1 had no effect on C3b binding. However, treatment of gC-2 with these endoglycosidases had a marked negative effect on C3b binding. These results suggest that N-linked oligosaccharides are involved in binding of C3b to gC-2, but not gC-1. Alternatively, removal of N-linked oligosaccharides from gC-2 might adversely affect polypeptide conformation. Glycoprotein C-2 also differs from gC-1 in its effects on the complement cascade. Whereas gC-1 accelerated the decay of the alternative pathway C3 convertase and impaired the efficiency of lysis by the components C5 through C9, gC-2 stabilized the active C3 convertase and had little effect on the late-acting components. The dissimilarity of gC-1 and gC-2 with regard to their effects on the complement cascade may have implications regarding the role of these glycoproteins in confronting the host immune response.     

Activation of natural killer cells by hepatitis C virus particles in vitro

Little is known about the ability of hepatitis C virus (HCV) to alter early innate immune responses in infected patients. Previous studies have shown that natural killer (NK) cells are functionally impaired after interaction of recombinant HCV glycoprotein E2 with the co-stimulatory CD81 molecule in vitro; however, the functional consequences of a prolonged contact of NK cells with HCV particles have remained unclear. We have examined the phenotypes of purified, interleukin-2-activated NK cells from healthy donors and HCV genotype 1b patients after culture for 5 days with HCV pseudoparticles (HCVpp) and serum samples containing HCV genotype 1b. NK cells from healthy donors and chronic HCV patients were found to up-regulate receptors associated with activation (NKp46, NKp44, NKp30, NKG2D), while NK receptors from the killer cell immunoglobulin-like receptor family (KIR/CD158), predominantly having an inhibitory function, were significantly down-modulated after culture in the presence of HCV particles compared with control cultures of NK cells. HCV-infected sera and HCVpp elicited significantly higher secretion of the NK effector lymphokines interferon-γ and tumour necrosis factor-α. Furthermore, HCV stimulated the cytotoxic potential of NK cells from normal donors and patients. The enhanced activation of NK cells after prolonged culture with HCVpp or HCV-containing sera for 5 days suggests that these innate effector cells may play an important role in viral control during early phases of HCV infection.     

Inhibition of the binding of HCV serum particles to human hepatocytes by E1E2‐specific D32.10 monoclonal antibody

The aim of this study was to determine the inhibition of binding activity of the monoclonal antibody (mAb) D32.10 which recognizes a highly conserved discontinuous antigenic determinant (E1:297–306, E2:480–494, and E2:613–621) expressed on the surface of serum‐derived HCV particles (HCVsp) of genotypes 1a, 1b, 2a, and 3a. To this end, an in vitro direct cell‐binding assay based on the attachment of radiolabeled HCVsp was developed, and Scatchard plots were used to analyze ligand–receptor binding data. HCV adsorption was also assessed by quantitating cell‐associated viral RNA by a real‐time RT‐PCR method. Saturable concentration‐dependent specific binding of HCVsp to Huh‐7 or HepaRG cells was demonstrated. The Scatchard transformed data showed two‐site interaction for Huh‐7 and proliferative HepaRG cells: the high‐affinity binding sites (K_d1 = 0.1–0.5 µg/ml) and the low‐affinity binding sites (K_d1 = 5–10 µg/ml), and one‐site high‐affinity binding model between E1E2/D32.10‐positive HCVsp and hepatocyte‐like differentiated HepaRG cells. The E1E2‐specific mAb D32.10 inhibited efficiently (>60%) and selectively the binding with an IC₅₀ ≤0.5 µg/ml in all the experimental approaches using serum HCV of genotype either 3 or 1b. This supports the involvement of the E1E2/D32.10 discontinuous antigenic determinant in the interactions between human hepatocytes and HCVsp, and suggests that D32.10‐like antibodies present in sera from patients infected with HCV could play a protective role. J. Med. Virol. 81:1726–1733, 2009. © 2009 Wiley‐Liss, Inc.     

52 例病毒性肝炎患者肝组织中丙型肝炎病毒 RNA 和 HCAg-NS3 的测定

应用地高辛标记探针原位杂交法和单克隆抗ＨＣＶ－ＮＳ３－ＨＲＰ建立直接酶标免疫组化法分别测定５２例肝炎患者肝组织ＨＣＶＲＮＡ和ＨＣＡｇ－ＮＳ３。结果抗ＨＣＶ阳性组ＨＣＶＲＮＡ检出率５７．１％（１６／２８），ＨＣＡｇ－ＮＳ３检出率５３．６％（１５／２８）；抗ＨＣＶ阴性组其两项检出率均为１２．５％（３／２４）。肝组织中ＨＣＶＲＮＡ阳性物呈蓝紫色细小颗粒存在于肝细胞核或胞浆内，其在肝小叶中的分布可分为３型，即弥漫型、局灶型、散在型。肝组织中ＨＣＡｇ－ＮＳ３阳性物呈棕黄色细小颗粒分布于肝细胞核或胞浆内，以单个或数个阳性细胞散布于肝小叶中。２３例ＨＣＶＲＮＡ或／和ＨＣＡｇ－ＮＳ３阳性病例以肝炎后肝硬化（ＬＣ）病例占多数（１４／２３），其次为慢性重型肝炎（ＣＳＨ）和中度慢性肝炎（ＣＡＨ）。此两种检测方法具有较高符合率（９０．４％，４７／５２），表明病毒核酸及其表达产物均存在于肝细胞内，与ＨＣＶ感染密切相关。这为ＨＣＶ感染诊断提供了直接依据，有利于研究ＨＣＶ感染中病毒复制、慢性化进程、抗病毒治疗监测及重叠感染时病毒相互关系。     

Evaluation of a chimpanzee colony for antibodies to hepatitis C virus.

The chimpanzee is the only species other than man that is generally susceptible to infection by hepatitis C virus (HCV). Aspects of future studies on vaccines and therapeutics for HCV may continue to depend on the chimpanzee. In an attempt to determine the HCV status of the animals in a chimpanzee colony, the recently developed enzyme immunoassay (EIA) for antibodies to HCV was used. The results of the assay indicated that only 31.3% of the animals that had previously been inoculated with a non-A, non-B hepatitis agent were currently positive in the assay. A retrospective analysis suggested that an additional 20% of the chimpanzees had been positive at some time following infection. Seroconversion to an anti-HCV antibody response using this assay did not appear to correlate with the severity of the initial disease or the development of chronic liver damage. Examination of the EIA-positive samples using the second generation recombinant immunoblot assay (RIBA) containing four HCV antigens suggested that chimpanzees responded differentially to these antigens. Examination of serum samples from 139 uninoculated animals by EIA revealed seven positive samples and ten samples with borderline values. The nature of the reactivities in most of the positive samples could not be resolved, but analysis by RIBA indicated that at least one animal in the breeder colony had been exposed to HCV. Due to the low seroconversion rate and the uncertainties surrounding many of the positive reactions, this assay cannot be used to determine the initial source or extent of spread of HCV infections in the uninoculated animals.     

HCV E2 glycoprotein: mutagenesis of N-linked glycosylation sites and its effects on E2 expression and processing

An expression system for analysis of the synthesis and processing of the E2 glycoprotein of a hepatitis C virus (HCV) genotype 1a strain was developed in transiently transfected cells. E2 proteins representing the entire length of the protein, including the transmembrane segment (E2) as well as two truncated versions (E2(660) and E2(715)), were characterized for acquisition of N-linked glycans and transport to the media of transfected cells. To investigate the utilization of the 10 potential N-linked glycosylation sites on this E2 protein, a series of mutations consisting of single or multiple (two, three, four or eight) ablations of asparagine residues in the background of the E2(660) construct were analyzed. E2(660) proteins harboring single or multiple site mutations were produced at levels similar to that of wild-type protein, but secretion of the single mutants was mildly diminished, and elimination of two or more sites dramatically reduced delivery of the protein to the media. Similar results were obtained in Huh-7 cells with respect to intracellular synthesis and secretion of the mutant proteins. Analysis of oligosaccharide composition using endoglycosidase digestion revealed that all of the glycan residues on the intracellular forms of E2(660), E2(715), and E2 contained N-linked glycans modified into high-mannose carbohydrates, in contrast to the secreted forms, which were endo H resistant. The parental E2(660) protein could be readily detected in Huh-7 cells using anti-polyhistidine or antibody to recombinant E2. In contrast, E2(660) lacking the eight N-linked glycans was expressed but not detectable with anti-E2 antibody, and proteins lacking four glycans exhibited reduced reactivity. These experiments provide direct evidence that the presence of multiple N-linked glycans is required for the proper folding of the E2 protein in the ER and secretory pathway as well as for formation of its antigenic structure.     

Individual expression of sindbis virus glycoproteins. E1 alone promotes cell fusion

The envelope of alphavirus particles contains two major glycoproteins, E1 and E2, that participate in virus entry and assembly of new virus particles. Interactions between these glycoproteins determine their correct functioning. The expression of each glycoprotein in the absence of the other counterpart was achieved by means of electroporation of modified Sindbis virus (SV) genomes. In addition, in trans coexpression of both glycoproteins was also tested in BHK cells. Synthesis of the E1 glycoprotein alone gave rise to cell fusion after incubation in low-pH medium. In addition, expression of E1 in the absence of the E2 precursor, PE2 (E3+E2), induced the formation of cytoplasmic vacuoles in the transfected cells. The normal phenotype was recovered when PE2 was coexpressed in trans with E1. Moreover, this coexpression modified the processing of the PE2 glycoprotein. PE2 synthesized in the absence of E1 gave rise to a product, E2', whose migration was slower in SDS-polyacrylamide gel than that of genuine E2 from SV-infected cells. This alteration was corrected upon in trans coexpression of E1 and PE2. These results suggest that the two glycoproteins, E1 and PE2, interact after their expression from two separate SV genomes. Notably, BHK cells cotransfected with the two modified genomes produced SV particles. Our findings suggest that SV E1 and E2 synthesized in trans can interact with each other and participate together with capsid protein in the assembly of new virus particles.     

Evaluation of hepatitis C antibody testing in saliva specimens collected by two different systems in comparison with HCV antibody and HCV RNA in serum

Two different ELISA assays, the Ortho HCV 3.0 ELISA (Ortho Diagnostics Systems) and the Mono-Lisa anti-HCV Plus (Sanofi Diagnostics Pasteur) were evaluated for the detection of hepatitis C virus (HCV) antibody in saliva samples. Specimens were collected from 152 individuals who participated in a longitudinal cohort study on HIV infection, and who used illicit drugs. Saliva specimens were collected using two different systems: Salivette (Sarstedt) and Omni-Sal (Saliva Diagnostic Systems). Saliva specimens were tested following modified protocols by both ELISAs, and the results were compared with serum specimens that were tested according to the instructions of the manufacturer. Serum samples of 102 (67%) participants were positive by both assays, and 50 persons were negative for HCV antibody. A total of 99 of the 102 serum specimens were confirmed as positive using Ortho Riba HCV 3.0 (Ortho Diagnostics System) and Deciscan HCV (Sanofi Diagnostics Pasteur), and 3 yielded discrepant results. As no cut-off level is known for testing saliva samples by ELISA, 3 different levels were chosen: mean (M) + 1 standard deviation (SD), M + 2 SD, and M + 3 SD of the optical densities of saliva tests of the 50 HCV serum antibody negative persons. At a level of M + 1 SD and M + 2 SD the Salivette/Mono-Lisa combination gave the greatest proportion of HCV antibody positive saliva specimens obtained from the 102 HCV serum antibody positive participants, 88% and 79%, respectively. Differences between the various collection systems and assay combinations were not significant statistically. In 76 of the 102 persons with HCV antibodies in serum, HCV RNA was detected in serum. Salivary presence of HCV RNA, however, could not be demonstrated. The results show that the assays compared are unsuitable for diagnostic use, but the sensitivities of the assays are acceptable for use in epidemiological studies.     

HCV 5′ NCR和结构蛋白编码序列的拼接及在pLNSX中的克隆

目的:构建丙型肝炎病毒(HCV)5′末端非编码区(5′NCR)和结构蛋白编码基因序列逆转录病毒重组体,用于探索控制HCV感染的新途径和基因治疗。方法:对多株HCV核酸序列进行同源性比较设计引物,逆转录聚合酶链式反应(RT-PCR)扩增5′NCR、C、E1和E2/NS14个编码区共5个片段,分别克隆。以连接聚合酶链反应(PCR)将这5个片段拼接为一连续的长2547nt的片段,含HCV完整的5′NCR和全部的结构蛋白编码序列。将此序列插入pGEM-Zf(+)载体,与逆转病毒pLNSX载体中,转化大肠杆菌DH5a、转化菌落经酶切、PCR和Southern杂交鉴定。结果:通过RT-PCR和连接聚合酶链式反应(PCR)扩增出2547nt含HCV完整的5′NCR和全部的结构蛋白编码序列,将此序列与pGEM-Zf(+)重组得重组体pHC2547,与逆转录病毒载体pLNSX重组得pL-HC。结论:成功构建了HCV逆转病毒重组体,以利于HCV的胞内基因表达调控研究,更为探索HCV分子致病机制和转基因动物及基因治疗提供可靠的物质基础。     

Rapid viral response and treatment outcome in genotype 2 and 3 chronic hepatitis C: comparison between two HCV RNA quantitation methods

Fifty consecutive patients with genotype 2 or 3 chronic hepatitis C were treated with peg-IFN alfa-2a 135 microg weekly and ribavirin (11 mg/kg body weight) daily during 24 weeks. Rapid viral response treatment week 4, end-of-treatment response, and sustained viral response were analyzed by two different HCV RNA quantitation methods, the Cobas Amplicor Monitor test and the TaqMan test with a sensitivity of 600 and 15 IU/ml, respectively. The TaqMan test differentiated patients with rapid viral response finally achieving sustained viral response better. Hence, patients with and without rapid viral response as tested by the TaqMan test finally achieved sustained viral response in 97% (32/33) versus in 75% (12/16), P < 0.017. The corresponding figures for the Cobas Amplicor test was 91% (41/45) versus (80%) 4/5 a non-significant difference. In conclusion, the more sensitive TaqMan test yielded a lower number of patients with rapid viral response than the less sensitive Amplicor Monitor test, but predicted sustained viral response in a higher percentage of patients with rapid viral response than the Amplicor Monitor test. A rapid viral response meaning HCV RNA levels <15 IU/ml predicted a sustained viral response in 97% of patients with genotype 2 or 3.     

静脉药瘾者丙型肝炎病毒感染及其相关因素的分析

目的了解静脉药瘾者丙型肝炎病毒（HCV）感染状况及其影响因素。方法381例静脉药瘾者作为研究对象，采集血清，用酶联免疫吸附法（ELISA）和聚合酶链反应（PCR）观察HCV感染和常见的血源传播病毒的感染指标。结果静脉药瘾者中抗HCV阳性261人（68．5％），感染率与当地正常人群比较，差异有统计学意义（P〈0．01），单因素分析表明HCV感染与吸毒史长短、共用注射器者和重叠HIV／HBV感染相关。Logistic逐步回归分析主要因素是HIV感染、吸毒史和共用注射器。结论静脉药瘾者是HCV感染的高危人群，而吸毒史长、共用注射器和伴发HIV／HBV感染时，使机体易感性增高，静脉药瘾者是丙型肝炎的重点防治对象。     

Genotype distribution and comparison of the putative envelope region of hepatitis C virus from Korean patients

Comparative nucleotide sequence studies of the genomes of hepatitis C virus (HCV) revealed that there are at least 6 different genotypes of HCV. The prevalence of HCV genotypes among the patients with liver diseases in Korea was investigated using the polymerase chain reaction (PCR) for the NS5 region. In the 75 HCV RNA positive samples, two genotypes, type 1b and type 2a, were the major causative agents which accounted for 60% and 33% of infections respectively, while 7% could not be assigned a genotype by the methods used. The nucleotide sequences of cDNAs encoding the putative envelope proteins from 10 type 1b and 5 type 2a genotype samples were analyzed. Approximately 31–42% of the nucleotide sequences of type 1b samples examined differed from those of different genotypes, In the case of type 2a samples, 36–42% of the nucleotide sequences differed from those of different genotypes. The diversities of the amino acid sequences were the same or greater than those of the nucleotide sequences. Two hypervariable regions (HVR1 and HVR2) were recognized in both HCV genomes of genotypes 1b and 2a. However, the sequence divergence within the HVR2 region of genotype 2a was less than that of genotype 1b. © 1995 Wiley-Liss, Inc.     

Predominance of HCV type 2a in saliva from intravenous drug users

Paired serum and saliva samples were collected simultaneously from 50 intravenous drug users with serologically proven hepatitis C virus infection. The oral health of the volunteers was also assessed. Hepatitis C virus RNA was detected by nested PCR, employing primers from the 5′ non-coding region. Positive PCR products were sequenced using the Sequenase PCR Product Sequencing Kit (Amersham Life Sciences). HCV RNA was detected in 33 (66%) of the 50 serum samples. HCV RNA was detected in 19 (57.6%) of the corresponding 33 saliva samples. There was no correlation between oral health status or HIV seropositivity and the detection of HCV in saliva. However, subjects with HCV in their saliva were significantly more likely to complain of xerostomia (P < 0.05). Isolate genotypes were identified in paired serum and saliva of 15 intravenous drug users. HCV genotypes 1, 2, 3 and 6 were detected in both specimens. In seven cases, a differing HCV genotype was found in serum compared to the paired saliva specimen. The distributions of genotypes in serum and saliva were very different, with genotype 2a more common in saliva than serum (P < 0.005). These data suggest that in some cases the source of salivary HCV may not be serum transudation along the periodontal membrane or across damaged mucosa, and that an alternative local source, possibly the salivary glands themselves, should be considered. J. Med. Virol. 54:271–275, 1998. © 1998 Wiley-Liss, Inc.