High Hepatitis B Surface Antigen Levels Predict Insignificant Fibrosis in Hepatitis B e Antigen Positive Chronic Hepatitis B

Introduction

There is no data on the relationship between hepatitis B surface antigen (HBsAg) levels and liver fibrosis in hepatitis B e antigen (HBeAg)-positive patients with chronic hepatitis B (CHB).

Methods

Serum HBsAg and HBV DNA levels in HBeAg-positive CHB patients with liver biopsies were analyzed. The upper limit of normal (ULN) of alanine aminotransferase (ALT) was 30 and 19 U/L for men and women respectively. Histologic assessment was based on Ishak fibrosis staging for fibrosis and Knodell histologic activity index (HAI) for necroinflammation.

Results

140 patients (65% male, median age 32.7 years) were recruited. 56 (40%) had ALT ≤2×ULN. 72 (51.4%) and 42 (30%) had fibrosis score ≤1 and necroinflammation grading ≤4 respectively. Patients with fibrosis score ≤1, when compared to patients with fibrosis score >1, had significantly higher median HBsAg levels (50,320 and 7,820 IU/mL respectively, p<0.001). Among patients with ALT ≤2×ULN, serum HBsAg levels achieved an area under receiver operating characteristic curve of 0.869 in predicting fibrosis score ≤1. HBsAg levels did not accurately predict necroinflammation score. HBsAg ≥25,000 IU/mL was independently associated with fibrosis score ≤1 (p = 0.025, odds ratio 9.042).Using this cut-off HBsAg level in patients with ALT ≤2×ULN, positive and negative predictive values for predicting fibrosis score ≤1 were 92.7% and 60.0% respectively. HBV DNA levels had no association with liver histology.

Conclusion

Among HBeAg-positive patients with ALT ≤2×ULN, high serum HBsAg levels can accurately predict fibrosis score ≤1, and could potentially influence decisions concerning treatment commencement and reduce the need for liver biopsy.     

用Far-Western印迹技术筛选人肝组织中与乙肝病毒表面抗原PreS1相互作用的蛋白

目的:利用Far-Western印迹技术从正常人肝组织中筛选乙型肝炎病毒(HBV)表面抗原PreS1结合蛋白,为阐明HBV的感染致病机理提供依据。方法:提取正常人肝组织细胞膜蛋白,双向电泳展示后转膜,对表达纯化获得的PreS1的重要片段与GST的融合蛋白PreS/1-48myr-GST进行Far-Western印迹实验,对筛选获得的蛋白点切胶,质谱鉴定。结果:对PreS/1-48myr-GST融合蛋白进行Far-Western-2D筛选,共获得22个蛋白点,经质谱鉴定获得15个候选相互作用蛋白,其中膜蛋白Ezrin可能在HBV感染致病过程中具有重要作用。结论:Ezrin蛋白能够与乙肝病毒表面抗原PreS1结合,其在HBV感染致病过程中的重要作用值得探索。     

纳米磁性颗粒标记的免疫层析法定量检测人乙型肝炎表面抗原

目的:应用纳米磁性颗粒标记的免疫层析法,研制可应用于乙肝表面抗原(HBsAg)快速定量检测的层析试纸条。方法:用1-乙基-3-(3-二甲基氨丙基)-碳化二亚胺(EDC)/N-羟基琥珀酰亚胺(NHS)交联的方法标记纳米磁珠,喷膜仪喷点硝酸纤维膜;根据双抗体夹心法原理建立免疫层析试纸条,对HBsAg特异性抗体捕获的磁信号进行检测,并对磁信号检测结果进行统计学分析和评价。结果:建立了HBsAg纳米磁性免疫层析试纸条,最低限度检测为0.1 ng/mL的HBsAg抗原,检测灵敏度达到了同类产品ELISA分析法的标准,且检测时间控制在5 min内;经检测临床血清标本证实,该方法可根据磁信号定量检测乙肝患者血清中HBsAg的浓度。结论:HBsAg纳米磁性免疫层析方法具有简单快速、灵敏度高的特点,可应用于临床血清样本中HBsAg的检测;该方法为体内极微量抗原抗体的快速检测建立了新模式。     

A Human Monoclonal Antibody against Hepatitis B Surface Antigen with Potent Neutralizing Activity

We describe the production and characterization of human monoclonal antibodies (mAb) specific for the major hepatitis B virus (HBV) S protein. The mAbs, two IgG1κ and one IgG1λ, were secreted by B-cell clones obtained from peripheral blood mononuclear cells (PBMC) of one person convalescent from acute hepatitis B and one vaccinated individual. The former recognized a denaturation-insensitive epitope within the p24 protein whereas the latter recognized a denaturation-sensitive, conformational epitope located within the HBsAg common “a” determinant. This mAb, denominated ADRI-2F3, displayed a very high protective titer of over 43,000 IU/mg mAb and showed an extremely potent neutralizing activity in the in vitro model of HBV infection using primary hepatocytes from Tupaia belangeri as target. Recombinant variable heavy and light domain sequences derived from mAb ADRI-2F3 were cloned into eukaryotic expression vectors and showed identical fine specificity and 1 log₁₀ higher titer than the original IgG1λ. It is envisaged that such mAb will be able to efficiently prevent HBV reinfection after liver transplantation for end-stage chronic HBV infection or infection after needle-stick exposure, providing an unlimited source of valuable protective anti-HBs antibody.     

乙肝病毒表面抗原基因在人参细胞中的表达

为获得表达乙肝病毒表面抗原(HBsAg)的人参细胞系,构建携带HBsAg基因的植物细胞表达载体pBIBSa,采用以农杆菌LBA4404感染的方法,经G418筛选后得到13株具有抗性的人参细胞.提取基因组DNA进行PCR反应,其中8株得到约700bp的HBsAg基因片段;提取mRNA进行RT-PCR反应,其中6株得到约700bp的HBsAg基因片段;用ELISA方法检测HBsAg,6株均为阳性.每克人参细胞中最高含HBsAg184 ng,占细胞可溶性蛋白的0.009%.免疫组化切片染色显示HBsAg主要分布在细胞膜上,少量位于细胞核中.这些结果表明人参细胞整合了HBsAg基因,并能稳定表达HBsAg.     

Hepatitis B Antigen Inhibitor in Human Faeces and Intestinal Mucosa

Hepatitis B antigen (HB Ag) positive sera became negative after in-vivo incubation with homogenates of human faeces or intestinal mucosa. This was found to occur in all sera tested by various methods. These findings suggest the existence in the human intestine of a substance able to inactivate the HB Ag and that it is not an antibody or of the nature of interferon. The presence of an inhibitor could explain why B-type hepatitis is seldom if ever faecally transmitted and also the low oral infectiousness of the B virus.     

DNA Polymerase Associated with Human Hepatitis B Antigen

DNA polymerase activity was detected in each of eight preparations of concentrated human hepatitis B antigen (HBAg) rich in Dane particles prepared by high-speed centrifugation of antigen-positive human plasma and in none of seven control preparations prepared in the same way from HBAg-negative plasma. The incorporation of (3)H-thymidine-methyl-5'-triphosphate into DNA was dependent on four deoxyribonucleoside triphosphates and MgCl(2). Treatment of the concentrated HBAg preparations with the nonionic detergent Nonidet P-40 (NP40) more than doubled the enzyme activity. Fractionation of the concentrated HBAg preparation in sucrose density gradients after treatment with NP40 revealed that the enzyme activity appeared within the density range of Dane core antigen but at a slightly higher density than the average for core antigen. The only particles observed by electron microscopy in this region of the gradient were typical 28-nm cores, suggesting that the DNA polymerase activity was associated with a subpopulation of cores. No DNA polymerase activity was found in purified 20-nm HBAg particles. The DNA product of the reaction remained associated with the 110S core and was not susceptible to DNase digestion when associated with the core. Inhibition of the reaction by actinomycin D and daunomycin suggested that the reaction was dependent on a DNA template associated with the core.     

抗HBsAg人源单链可变区抗体的筛选与可溶性抗体的表达

采用噬菌体表达展示技术,以从乙型肝炎病毒（HBV）表达抗原（HBsAg）阳性血汪有超速离心纯化的HBsAg为固相抗原,从噬菌体单链可变区半合成抗体库中经过5轮“吸附－洗脱－扩增”筛选过程,获得特异性较强的HBsAg人源单链可变区抗体（ScFv）克隆并提取质粒,经SfiⅠ/NotⅠ酶切鉴定后,亚克隆到pCANTAB5E表达载体中,转化大肠杆菌XL1－Blue。经IPTG诱导后,表达的可溶性HBsAg特异性ScFv以50％硫酸胺沉淀,经SDS－PAGE电泳表明,XL1－Blue中表达的HBsAg可溶性ScFv的分子量约28kD。免疫活性检测结果表明,该单链抗体具有较强的抗原结合性和特异性。HBsAg人源单链抗体的筛选和表达成功,为今后HBsAg人源抗体的研究和应用奠定了基础。     

抗HBsAg人源单链可变区抗体的筛选与可溶性抗体的表达

采用噬菌体表面展示技术,以从乙型肝炎病毒(HBV)表面抗原(HBsAg)阳性血清超速离心纯化的HBsAg为固相抗原,从噬菌体单链可变区半合成抗体库中经过5轮“吸附-洗脱-扩增”筛选过程,获得特异性较强的HBsAg人源单链可变区抗体(ScFv)克隆并提取质粒,经SfiⅠ/NotⅠ酶切鉴定后,亚克隆到pCANTAB5E表达载体中,转化大肠杆菌XL1-Blue。经IPTG诱导后,表达的可溶性HBsAg特异性ScFv以50%硫酸胺沉淀,经SDS-PAGE电泳表明,XL1-Blue中表达的HBsAg可溶性ScFv的分子量约28?kD。免疫活性检测结果表明,该单链抗体具有较强的抗原结合活性和特异性。HBsAg人源单链抗体的筛选和表达成功,为今后HBsAg人源抗体的研究和应用奠定了基础。     

人抗体组合文库的构建和抗HBsAg噬菌体抗体的筛选

应用噬菌体表面递呈表达系统构筑建了人抗体组合文库,并同了结合乙肝表面抗原（ＨＢｓＡｇ）的人噬菌体抗体（Ｆａｂ片段）。以免疫球蛋白信号肽序列为引物进行半套式ＰＣＲ所得到的产物在质和量上优越于以可变区５末端保守库列为引物进行ＰＣＲ所得到的产物,经过３次亲和选择后,抗体阳性率为６９％,抑制实验表明,所筛选出来的噬菌体本具有抗ＨＢｓＡｇ的特异性,序更分析表明ＶＨ分别属于ＶＨＩ亚群和Ⅲ亚群,其轻链ＶＬ分别属     

Expression and Characterization of Hepatitis B Surface Antigen in Transgenic Potato Plants

Transgenic potato plants expressing the gene of hepatitis B surface antigen (HBsAg) under the control of the double promoter of 35S RNA of cauliflower mosaic virus (CaMV 35SS) and the promoter of patatin gene of potato tubers have been obtained. Biochemical analysis of the plants was performed. The amount of HBsAg in leaves, microtubers, and tubers of transgenic potatoes growing in vitro and in vivo was 0.005-0.035% of the total soluble protein. HBsAg content reached 1 microg/g in potato tubers and was maximal in plants expressing the HBsAg gene under the control of CaMV 35SS promoter. In transgenic plants expressing HBsAg gene under the control of tuber-specific patatin promoter, HBsAg was found only in microtubers and tubers and was absent in leaves. Western blot analysis of HBsAg eluted from immunoaffinity protein A-Sepharose matrix has been performed. The molecular weight of HBsAg peptide was approximately 24 kD, which is in agreement with the size of the major protein of the envelope of hepatitis B virus. Using gel filtration, it was determined that the product of HBsAg gene expression in potato plants is converted into high-molecular-weight multimeric particles. Therefore, as well as in recombinant HBsAg-yeast cells, assembling of HBsAg monomers into immunogenic aggregates takes place in HBsAg-transgenic potato, which can be used as a source of recombinant vaccine against hepatitis B virus.     

Hepatocellular Carcinoma in Hepatitis B Surface Antigen Carriers in Eight Institutions

We reviewed records of all persons dying between 1979 and 1986 in eight California institutions for the mentally retarded. Autopsies had been done in 71% of the 1,181 deaths. Nine deaths were due to hepatocellular carcinoma, which invariably developed in carriers of hepatitis B surface antigen (HBsAg) and was fatal within four months of diagnosis. The mean age at death was 32.7 years. The incidence of hepatocellular carcinoma in HBsAg carriers was 140 times greater than in the US population. Persistent hepatitis B infection was probably etiologically related to hepatocellular carcinoma in this population, which is relatively free of exposure to other hepatocarcinogens.     

Structural Relationships Between Minor and Major Proteins of Hepatitis B Surface Antigen

The minor glycoproteins from hepatitis B surface antigen, GP33 and GP36, contain at their carboxy-terminal part the sequence of the major protein P24. They have 55 additional amino acids at the amino-terminal part which are coded by the pre-S region of the viral DNA.     

Rare Detection of Occult Hepatitis B Virus Infection in Children of Mothers with Positive Hepatitis B Surface Antigen

The prevalence of occult Hepatitis B virus (HBV) infection in children was considerably varied from 0.1–64% in different reports. In this study we aimed to investigate the prevalence of occult HBV infection among the children born to mothers with positive hepatitis B surface antigen (HBsAg) in Jiangsu, China. Serum samples were collected from 210 children of 207 mothers with positive HBsAg. HBV serological markers were detected by ELISA and HBV DNA was detected by nested PCR. Homology comparison of HBV sequences recovered from the child and mother was used to define the infection. Three children (1.43%) were positive for HBsAg, in whom the HBV pre S and S gene sequence in each child was identical to that in her mother. Of the 207 HBsAg-negative children, nine displayed HBV DNA positive by two nested PCR assays using primers derived from S and C genes. However, the sequence alignment showed that the sequences in each child were considerably different from those in his/her mother. Therefore, the sequences amplified from the children were very likely resultant from the cross-contaminations. Furthermore, the nine children with ‘positive HBV DNA’ were all negative for anti-HBc, and one had anti-HBs 3.42 mIU/ml and eight others had anti-HBs from 72 to >1000 mIU/ml, indicating that the nine children were less likely infected with HBV. Therefore, none of the 207 HBsAg-negative children of HBV-infected mothers was found to have occult HBV infection. We conclude that the prevalence of occult HBV infection in vaccinated children born to HBsAg positive mothers should be extremely low. We recommend that homology comparison of sequences recovered from the child and mother be used to define the occult HBV infection in children born to HBV infected mothers.     

Familial Clustering of Hepatitis B Antigen: A Study in Relatives of Patients with Liver Diseases and Hepatitis B Antigenaemia

Twelve of the 100 family contacts of 29 patients with transient and persistent hepatitis B antigenaemia were found to be positive for hepatitis B antigen (HBAg). No relation was found between familial clustering and the nature of liver disease or the duration of antigenaemia in the index cases.Eight affected relatives were apparently healthy carriers of HBAG, one had cirrhosis, and three (in the same family) developed acute viral hepatitis.The absence of parenteral exposure in the HBA,-positive family contacts and the identity in antigenic determinants d or y with those of the index cases, suggest a non-parenteral spread of HBAg in families of patients with HBAg-associated liver diseases.     

Hepatitis B Surface Antigen Concentrations in Patients with HIV/HBV Co-Infection

HBsAg clearance is associated with clinical cure of chronic hepatitis B virus (HBV) infection. Quantification of HBsAg may help to predict HBsAg clearance during the natural course of HBV infection and during antiviral therapy. Most studies investigating quantitative HBsAg were performed in HBV mono-infected patients. However, the immune status is considered to be important for HBsAg decline and subsequent HBsAg loss. HIV co-infection unfavorably influences the course of chronic hepatitis B. In this cross-sectional study we investigated quantitative HBsAg in 173 HBV/HIV co-infected patients from 6 centers and evaluated the importance of immunodeficiency and antiretroviral therapy. We also compared 46 untreated HIV/HBV infected patients with 46 well-matched HBV mono-infected patients. HBsAg levels correlated with CD4 T-cell count and were higher in patients with more advanced HIV CDC stage. Patients on combination antiretroviral therapy (cART) including nucleos(t)ide analogues active against HBV demonstrated significant lower HBsAg levels compared to untreated patients. Importantly, HBsAg levels were significantly lower in patients who had a stronger increase between nadir CD4 and current CD4 T-cell count during cART. Untreated HIV/HBV patients demonstrated higher HBsAg levels than HBV mono-infected patients despite similar HBV DNA levels. In conclusion, HBsAg decline is dependent on an effective immune status. Restoration of CD4 T-cells during treatment with cART including nucleos(t)ide analogues seems to be important for HBsAg decrease and subsequent HBsAg loss.     

Total Hepatitis B Core Antigen Antibody,a Quantitative Non-Invasive Marker of Hepatitis B Virus Induced Liver Disease

Non invasive immunologic markers of virus-induced liver disease are unmet needs. We tested the clinical significance of quantitative total and IgM-anti-HBc in well characterized chronic-HBsAg-carriers. Sera (212) were obtained from 111 HBsAg-carriers followed-up for 52 months (28-216) during different phases of chronic-HBV-genotype-D-infection: 10 HBeAg-positive, 25 inactive-carriers (HBV-DNA≤2000IU/ml, ALT<30U/L), 66 HBeAg-negative-CHB-patients and 10 with HDV-super-infection. In 35 patients treated with Peg-IFN±nucleos(t)ide-analogues (NUCs) sera were obtained at baseline, end-of-therapy and week-24-off-therapy and in 22 treated with NUCs (for 60 months, 42-134m) at baseline and end-of-follow-up. HBsAg and IgM-anti-HBc were measured by Architect-assays (Abbott, USA); total-anti-HBc by double-antigen-sandwich-immune-assay (Wantai, China); HBV-DNA by COBAS-TaqMan (Roche, Germany). Total-anti-HBc were detectable in all sera with lower levels in HBsAg-carriers without CHB (immune-tolerant, inactive and HDV-superinfected, median 3.26, range 2.26-4.49 Log₁₀ IU/ml) versus untreated-CHB (median 4.68, range 2.76-5.54 Log₁₀ IU/ml), p<0.0001. IgM-anti-HBc positive using the chronic-hepatitis-cut-off" (0.130-S/CO) were positive in 102 of 212 sera (48.1%). Overall total-anti-HBc and IgM-anti-HBc correlated significantly (p<0.001, r=0.417). Total-anti-HBc declined significantly in CHB patients with response to Peg-IFN (p<0.001) and in NUC-treated patients (p<0.001); the lowest levels (median 2.68, range 2.12-3.08 Log₁₀ IU/ml) were found in long-term responders who cleared HBsAg subsequently. During spontaneous and therapy-induced fluctuations of CHB (remissions and reactivations) total- and IgM-anti-HBc correlated with ALT (p<0.001, r=0.351 and p=0.008, r=0.185 respectively). Total-anti-HBc qualifies as a useful marker of HBV-induced-liver-disease that might help to discriminate major phases of chronic HBV infection and to predict sustained response to antivirals.     

Generation and Characterization of High Affinity Humanized Fab Against Hepatitis B Surface Antigen

5S is a mouse monoclonal IgG1 that binds to the ‘a’ epitope of the Hepatitis B surface antigen (HBsAg) and tested positive in an in vitro test for virus neutralization. We have earlier reported the generation of humanized single chain variable fragment (scFv) from the same. In this article we report the generation of a recombinant Fab molecule by fusing humanized variable domains of 5S with the constant domains of human IgG1. The humanized Fab expressed in E. coli and subsequently purified, retained a high binding affinity (K_D = 3.63 nmol/L) to HBsAg and bound to the same epitope of HBsAg as the parent molecule. The humanized Fab also maintained antigen binding in the presence of various destabilizing agents like 3 M NaCl, 30% DMSO, 8 M urea, and extreme pH. This high affinity humanized Fab provides a basis for the development of therapeutic molecules that can be safely utilized for the prophylaxis and treatment for Hepatitis B infection.