用重组痘苗病毒感染动物细胞表达的Epstein-Barr病毒膜抗原检查IgA/MA抗体

用EB病毒膜抗原基因重组的痘苗病毒感染动物细胞,其细胞表面可表达EB病毒膜抗原,以此膜抗原作为诊断抗原检测血清中IgA/MA抗体,明显优于常用的B95-8细胞表面膜抗原,从而为研究人群血清抗体反应与鼻咽癌的关系,为鼻咽癌的诊断和普查开辟了新的途径。     

激活Raji细胞EB病毒早期抗原植物的研究

以前材料证明Raji细胞EB病毒早期抗原对于诊断鼻咽癌有很高的特异性。我们研究了1693种植物,试验发现52种植物具有激活EB病毒作用。本文报道了这些植物并讨论它们与鼻咽癌关系。     

鼻咽癌患者血清中抗Epstein-Barr病毒早期和晚期膜抗原抗体的检测

对Epstein-Barr(EB)病毒抗原的研究,发现有淋巴细胞确定的膜抗原(Lydma)、早期抗原(EA)、壳抗原(VCA)、核抗原(EBNA)、早期膜抗原(EMA)和晚期膜抗原(LMA)。除了Lydma抗原外,鼻咽癌患者对上述抗原均产生相应的IgG和IgA抗体。因而研究这些抗体,对阐明EB病毒与鼻咽癌的关系及鼻咽癌的早期诊断都十分有价值。     

Epstein-Barr病毒相关的淋巴细胞确定的膜抗原和潜伏感染膜蛋白的某些生物学特性及其与鼻咽癌关系的研究进展

已有大量研究工作证实,Epstein-Barr(EB)病毒与鼻咽癌的关系十分密切。因而,EB病毒在鼻咽癌病因学中的作用引起了人们的广泛重视。在EB病毒与宿主细胞相互关系的研究中,抗原表达与细胞隐性感染和细胞转化的相互关系,是目前所确认的关键课题之一。近年来的研究已经表明,EB病毒感染宿主细胞后,有多种EB病毒的特异性抗原产生,包括早期抗原(EA)、壳抗原(VCA)、膜抗原(MA)、核抗原(EBNA)、淋巴细胞确定的膜抗原(Lymphocyte-defined membrane antigen,LYDMA)和EB病毒潜     

EB病毒诊断学意义及其方法学进展

EB病毒可以导致多种疾病,其与鼻咽癌的关系已得到确认。近年来发现EB病毒在人体内感染情况对于鼻咽癌的诊断、临床分期、预后判断和监测放疗后转移复发等均具有重要意义。各种EB病毒检测方法应运而生。本文就EB病毒诊断方法进展及其意义作一综述。     

土壤中含EB病毒诱导物的检测

从广西壮族自治区梧州市、苍梧县、罗城县和北京市收集的土壤标本中发现有EB病毒诱导物。梧州市和苍梧县沿公路和江河两旁桐油树下的土壤标本,对EB病毒早期抗原诱导的阳性率为40～58％。在其他大戟科植物下的土壤标本中,也发现有EB病毒诱导物。对桐油树下土壤中EB病毒诱导物与鼻咽癌发生的可能关系进行了讨论。     

Epstein-Barr病毒基因工程活疫苗人体免疫的初步研究

Epstein-Barr(EB)病毒的原发感染发生在儿童时期,在我国3～5岁儿童的感染率为70％～90％。感染后终生带毒,并经唾液不断排出病毒。我国南方是鼻咽癌高发区,其发病率和死亡率均占恶性肿瘤的第一位。早期诊断方法的改进和早期治疗,使鼻咽癌治疗后的5年生存率明显增加,但不能降低发病率。EB病毒疫苗有可能成为控制该病的有效手段之一。 Epstein等人从淋巴母细胞株(B95-8细胞)细胞表面提取EB病毒膜抗原(MA),用于免疫棉顶猴能产生中和抗体。免疫动物能抵抗EB病毒攻击后所诱发的恶性淋巴瘤。该中和抗体在体外能中和EB病毒的转化活性。EB病毒的主要膜抗原(MA)是由分子量220kD和     

EB病毒及其疫苗的研究进展

EB病毒广泛存在于人群中,它的潜伏感染与多种疾病密切相关,包括鼻咽癌等恶性肿瘤,研制疫苗用于EB病毒相关疾病的预防和治疗十分必要。本综述了EB病毒的结构及基因表达特点、EB病毒潜伏期感染基因表达及潜伏期基因产物的功能,以及研制EB病毒疫苗的靶抗原的选择。     

广西梧州市EB病毒IgA/VCA抗体阳性者的追踪观察

在广西梧州市对20,726人进行EB病毒IgA/VCA抗体血清学普查和4年追踪观察,共发现35例鼻咽癌病人,其中早期病人占91.5％。同期门诊查出的1,036例鼻咽癌中,早期病人仅占31.8％。在鼻咽癌确诊前16～41个月即可检出IgA/VCA抗体。说明EB病毒与鼻咽癌的发生关系密切,血清学普查和追踪观察对本病的早期诊断十分重要。     

细胞DNA倍体分析和EBERs原位检测在鼻咽癌早期诊断中的应用

目的　探讨鼻咽脱落细胞进行DNA倍体和EB病毒编码RNA (EBERs)检测在鼻咽癌诊断中的应用。方法　对 38例经细胞学诊断为鼻咽癌和 8例为正常的鼻咽细胞涂片分别进行图像分析测定细胞DNA含量和EB病毒EBERs原位杂交检测。结果　与病理细胞学诊断相比 ,DNA异倍体分析和EBERs检测诊断癌的敏感性分别为 5 0 %和 92 %,其特异性均为 10 0 %;其阴性预测值分别为 30 %和 72 %。结论　与EBERs检测相比 ,DNA异倍体分析的诊断敏感性和阴性预测值较低 ,差异具有显著性 (分别为P <0 0 0 1和P <0 0 5 )。证明在鼻咽细胞学涂片应用EB病毒原位杂交检测诊断鼻咽癌优于应用DNA异倍体分析诊断。与细胞DNA图像分析相比 ,EB病毒原位杂交检测具有客观、实验条件简单等优点 ,在鼻咽癌可疑病人的早期诊断和鉴别诊断上具有重要的实用价值。     

Epstein-Barr viral antigens used in the diagnosis of nasopharyngeal carcinoma

The major antigen complexes of Epstein-Barr virus (EBV) include the latent infectious proteins, early antigens, membrane antigens and viral capsid antigens. The various polypeptides within each antigen complex have been identified and isolated through gene-cloning technology. These polypeptides are exploited to be used as serological markers for the diagnosis of nasopharyngeal carcinoma (NPC) through enzyme-linked immunosorbent assay. This paper reviews the recent studies on the profile of antibodies in patients with NPC towards these EBV polypeptides of each antigen complex. The sensitivity and specificity of each polypeptide when used as serological markers to NPC patients' sera are summarized.     

Nasopharyngeal carcinoma patients from Norway show elevated Epstein-Barr virus IgA and IgG antibodies prior to diagnosis

BackgroundIgA antibodies against few Epstein-Barr virus (EBV) proteins are established serological markers for nasopharyngeal carcinoma (NPC). We recently validated a novel, comprehensive EBV marker panel and showed that IgA, but also IgG antibodies against multiple EBV proteins are highly sensitive and specific for EBV-positive NPC at diagnosis. However, data about these novel biomarkers as prospective markers for NPC are sparse.MethodsThis study included 30 incident NPC cases and 60 matched controls from the Norwegian Janus Serum Bank. For 21 NPCs, molecular EBV and human papillomavirus (HPV) status were assessed by EBER-ISH and HPV DNA/RNA testing by PCR, respectively. IgA and IgG serum antibodies against 17 EBV antigens were analyzed in prediagnostic sera of cases (median lead time 14 years) and controls using multiplex serology. Sensitivities were calculated using receiver operating characteristic analysis pre-specified to yield 90% specificity in the control group. From 10 cases, serial samples were available.ResultsQuantitative EBV antibody levels were significantly elevated among all cases (p < 0.05) for three IgA and six IgG antibodies. The highest sensitivities for defining 12 EBER-ISH-positive NPCs were observed for BGLF2 IgA (67%) and BGLF2 IgG (83%). Increased IgA and IgG antibody levels between the first and last draw before diagnosis were observed for EBER-ISH positive, but not for EBER-ISH negative NPCs. Among 21 molecularly analyzed NPCs, 4 EBER-ISH negative NPCs showed concomitant positivity to HPV type-specific DNA and RNA; 3 NPCs were HPV16 and 1 NPC was HPV18 positive.ConclusionBoth, EBV IgA and IgG antibody levels are significantly elevated many years before diagnosis of EBV-positive NPCs in Norway, an NPC low-incidence region. This study provides insights into one of the largest available prospective sample collections of NPCs in a non-endemic country.     

Sequential detection of different antigens induced by Epstein-Barr virus and herpes simplex virus in the same Western blot by using dual antibody probes

A dual antibody probing technique that permitted a color-coded identification of polypeptides representing different classes of Epstein-Barr virus (EBV) antigens as well as differentiation of the polypeptides induced by different herpesviruses in the same Western blot was developed. When the nitrocellulose sheet was probed first with monoclonal antibody against EBV early antigen diffuse component (EA-D) and then stained with 4-chloro-1-naphthol, four polypeptides specific for EA-D were identified by purple bands. Subsequently, the same nitrocellulose sheet was reprobed with human serum containing antibodies against EBV early antigen, viral capsid antigen, and nuclear antigen and stained with 3,3'-diaminobenzidine. Several brown bands corresponding to early, viral capsid, and nuclear antigen polypeptides were detected. The dual antibody probing technique was used in an analysis to differentiate polypeptides resulting from either EBV or herpes simplex virus infection, either in cells infected by individual virus or in a cell line dually infected by both viruses. On the basis of different colored bands in different lanes of the same gel, 20 polypeptides with molecular weights ranging from 31,000 to 165,000 were identified as herpes simplex virus-specific proteins. These results suggested that the dual antibody probing technique may be applicable in clinical diagnosis for detecting antigens and antibodies derived from different pathogens.     

Fluctuations of epstein-barr virus serological antibodies and risk for nasopharyngeal carcinoma: a prospective screening study with a 20-year follow-up

Background

The impact of variation of Epstein-Barr virus (EBV) antibody titers before the development of nasopharyngeal carcinoma (NPC) is still unclear. We analyzed the fluctuations of antibodies against EBV before histopathological diagnosis to assess the risk of NPC and aimed to provide a reliable basis for screening in high risk populations.

Methods

This study was based on a population-based screening program in Sihui County in Guangdong Province of China. A total of 18,986 subjects were recruited in 1987 and 1992, respectively. Baseline and repeated serological tests were performed for IgA antibodies against EBV capsid antigen (VCA/IgA) and early antigen (EA/IgA). Follow-up until the end of 2007 was accomplished through linkage with population and health registers. Cox proportional hazards regression model was used to estimate the relative risk of NPC in association with EBV antibodies. Time-dependent receiver operating characteristic curve (ROC) analysis was used to further evaluate the predictive ability.

Results

A total of 125 NPCs occurred during an average of 16.9 years of follow-up. Using baseline information alone or together with repeated measurements, serological levels of VCA/IgA and EA/IgA were significantly associated with increased risks for NPC, with a striking dose-response relationship and most prominent during the first 5 years of follow-up. Considering the fluctuant types of serological titers observed during the first three tests, relative risk was highest among participants with ascending titers of EBV VCA/IgA antibodies with an adjusted hazard ratio (HR) of 21.3 (95% confidence interval [CI] 7.1 to 64.1), and lowest for those with decreasing titers (HR = 1.5, 95% CI 0.2 to 11.4), during the first 5 years of follow-up. Time-dependent ROC analysis showed that VCA/IgA had better predictive performance for NPC incidence than EA/IgA.

Conclusion

Our study documents that elevated EBV antibodies, particularly with ascending titers, are strongly associated with an increased risk for NPC.     

实时定量PCR方法检测鼻咽癌病人全血EB病毒拷贝数的实验研究

EBV is detected in more and more tumors, and is relative to carcinogenesis. We studied the copies of EBV DNA in whole blood of NPC patients and healthy controls by real-time quantitative PCR. In the 73 NPC patients and 83 controls, the positive rate of EBV in blood of NPC is 46.6%, while 13.3% in control. The mean copy number is 3.9 x 10(4) copys/microgram DNA in controls, which is much higher than NPC patients (which is 1.7 x 10(5) copies/microgram DNA). EBV infection is relative with NPC, while the lytic form of EBV maybe more important than its latent form. These results suggest that whole blood EBV DNA may be a valuable tool for molecular diagnosis of NPC.     

Amplification of Epstein-Barr virus (EBV) DNA by superinfection with a strain of EBV derived from nasopharyngeal carcinoma.

Epstein-Barr virus (EBV) from a nasopharyngeal carcinoma (NPC) hybrid cell line (NPC-KT) lacking defective viral DNA molecules superinfected Raji cells and induced EBV early antigens (EA), as did virus from P3HR-1 cells, which contained defective molecules. The EBV polypeptides induced by NPC-KT appeared to be identical to those induced by P3HR-1 virus. The ability of NPC-KT virus to induce EA was enhanced more than 10-fold by treatment of superinfected cells with dimethyl sulfoxide; however, dimethyl sulfoxide treatment did not enhance superinfection by P3HR-1 virus. After infection, DNA synthesis of both the superinfecting NPC-KT virus and the resident Raji viral genome was induced. In addition to amplified Raji EBV episomal DNA, a fused terminal fragment of NPC-KT viral DNA was detected. The detection of fused terminal DNA fragments suggests that the superinfecting virion DNA either circularizes or polymerizes after superinfection and is possibly amplified through circular or concatenated replicative intermediates.     

用转染EB病毒基因片段的真核细胞检测鼻咽癌病人的抗EB病毒核抗原-1(EBNA-1)抗体

用转染EBV DNA Bam HI K片段后稳定表达EBNA-1的K_4细胞作为靶细胞,检测50份鼻咽癌病人和38份健康对照者血清中的IgG/EBNA-1抗体;阳性率分别为100％和92％。前者的平均几何滴度为89.4,后者为18.3,前者约为后者的5倍。同一批被检血清经SPA吸收去除IgG竞争性抑制后,鼻咽癌病人的IgA/EBNA-1抗体阳性率达78％(GMT 20.9),健康人的IgA/EBNA-1抗体阳性率仅5.3％,效价亦很低(GMT 5.2)。表明IgA/EBNA-1抗体对鼻咽癌是比较特异的,可考虑作为鼻咽癌血清学诊断的指标之一。     

Purification and properties of Epstein-Barr virus DNase expressed in Escherichia coli.

A cDNA corresponding to the BGLF5 open reading frame of the Epstein-Barr virus (EBV) genome and coding for an early DNase was inserted into the procaryotic expression vector pKK223-3. One bacterial clone producing the expected 52-kilodalton DNase was used as a source of EBV DNase. The 52-kilodalton Dnase was purified in the active form to near homogeneity by ammonium sulfate precipitation and successive chromatographies on phosphocellulose, DNA-cellulose, and gel filtration columns. The purified enzyme exhibited both exonuclease and endonuclease activities, an absolute requirement for divalent cations, an alkaline pH preference, and a typical residual activity in presence of 300 mM KCl. Moreover, the enzyme was specifically inhibited by human sera with high antibody titers to EBV early antigens. These properties are similar to those observed for EBV-induced DNase from lymphoblastoid cell extracts. In addition, the enzyme was recognized by both immunoglobulin G and A serum fractions from patients with nasopharyngeal carcinoma (NPC). From these results and previous studies which demonstrated the value of antibody titers to this viral DNase as an NPC marker, it appears that EBV-encoded DNase produced in a heterologous expression system could be used in the development of a specific and early NPC diagnosis test.     

EBV up-regulates cytochrome c through VDAC1 regulations and decreases the release of cytoplasmic Ca2+ in the NPC cell line

EBV (Epstein-Barr virus) is considered to be a major factor that causes NPC (nasopharyngeal carcinoma), which is one of the sneakiest cancers frequently occurring in Southeast Asia and Southern China. Apoptosis and pro-apoptotic signals have been studied for decades; however, few have extended the prevailing view of EBV to its impact on NPC in perspective of apoptosis. One of the important proteins named VDAC1 (voltage-dependent anion protein 1) on the mitochondrial outer membrane controls the pro-apoptotic signals in mammalian cells. The impact of EBV infection on VDAC1 and related apoptotic signals remains unclear. In order to study the VDAC1's role in EBV-infected NPC cells, we employ siRNA (small interfering RNA) inhibition to analyse the release of Ca2+ and Cyto c (cytochrome c) signals in the cytoplasm, as they are important pro-apoptotic signals. The results show a decrease of Ca2+ release and up-regulation of Cyto c with EBV infection. After siRNA transfection, the dysregulation of Cyto c is neutralized, which is evidence that the level of Cyto c release in virus-infected NPC cells is the as same as that of non-infected NPC cells. This result indicates that EBV infection changes the cytoplasmic level of Cyto c through regulating VDAC1. In summary, this study reports that EBV changes the release of Ca2+ and Cyto c in the cytoplasm of NPC cells, and that Cyto c changes are mediated by VDAC1 regulation.