Prevalence of HBsAg among reproductive age couples in Chongqing: A population-based, cross-sectional study

Hepatitis B is a leading cause of death worldwide. Here, we performed a large, population-based, cross-sectional study in Chongqing, China from 2011 to 2016 to assess the prevalence of HBsAg among couples of reproductive age, to predict subsequent trends, and to provide evidence for the WHO goal of "the elimination of viral hepatitis as a public health threat by 2030". A total of 386,286 couples aged 20 to 49 years were enrolled in the study. Approximately 14.35% of couples were HBsAg positive, including 95.00% with discordant HBsAg positivity. HBsAg prevalence was higher in men than in women. Among different occupations, the two categories of "houseworker" (female 6.73%, male 9.99%) and "unemployed" (female 6.64%, male 9.94%) showed the highest HBsAg positivity. In different regions, the lowest prevalence appeared in southeastern Chongqing (female 4.87%, male 7.71%). In 2030, the HBsAg positivity rate is expected to be 2.79%, 7.27% and 5.13% in females, males, and the whole population, respectively. According to the trends, this rate would drop to less than 2% in 2034, 2078 and 2051. In conclusion, the HBsAg prevalence in Chongqing is still relatively high compared with that in other parts of western China, especially among reproductive-age men. HBsAg-positive couples should be taken as an important unit of care. Vaccination is necessary before pregnancy if no antibody is found. More attention should be given to people without stable jobs. HBsAg-positive rate will decrease perceptibly by 2030 and will reach the level of low in epidemic areas by 2050.

A recombinant human immunoglobulin with coherent avidity to hepatitis B virus surface antigens of various viral genotypes and clinical mutants

The hepatitis B virus (HBV) envelope is composed of a lipid bilayer and three glycoproteins, referred to as the large (L), middle (M), and small (S) hepatitis B virus surface antigens (HBsAg). S protein constitutes the major portion of the viral envelope and an even greater proportion of subviral particles (SVP) that circulate in the blood. Recombinant S proteins are currently used as a preventive vaccine, while plasma fractions isolated from vaccinated people, referred to as hepatitis B immune globulin (HBIG), are used for short-term prophylaxis. Here, we characterized a recombinant human IgG1 type anti-S antibody named Lenvervimab regarding its binding property to a variety of cloned S antigens. Immunochemical data showed an overall consistent avidity of the antibody to S antigens of most viral genotypes distributed worldwide. Further, antibody binding was not affected by the mutations in the antigenic ‘a’ determinant found in many clinical variants, including the immune escape mutant G145R. In addition, mutations in the S gene sequence that confer drug resistance to the viral polymerase did not interfere with the antibody binding. These results support for a preventive use of the antibody against HBV infection.

Distinct disease features in chimpanzees infected with a precore HBV mutant associated with acute liver failure in humans

Transmission to chimpanzees of a precore hepatitis B virus (HBV) mutant implicated in acute liver failure (ALF) in humans did not cause ALF nor the classic form of acute hepatitis B (AHB) seen upon infection with the wild-type HBV strain, but rather a severe AHB with distinct disease features. Here, we investigated the viral and host immunity factors responsible for the unusual severity of AHB associated with the precore HBV mutant in chimpanzees. Archived serial serum and liver specimens from two chimpanzees inoculated with a precore HBV mutant implicated in ALF and two chimpanzees inoculated with wild-type HBV were studied. We used phage-display library and next-generation sequencing (NGS) technologies to characterize the liver antibody response. The results obtained in severe AHB were compared with those in classic AHB and HBV-associated ALF in humans. Severe AHB was characterized by: (i) the highest alanine aminotransferase (ALT) peaks ever seen in HBV transmission studies with a significantly shorter incubation period, compared to classic AHB; (ii) earlier HBsAg clearance and anti-HBs seroconversion with transient or undetectable hepatitis B e antigen (HBeAg); (iii) limited inflammatory reaction relative to hepatocellular damage at the ALT peak with B-cell infiltration, albeit less extensive than in ALF; (iv) detection of intrahepatic germline antibodies against hepatitis B core antigen (HBcAg) by phage-display libraries in the earliest disease phase, as seen in ALF; (v) lack of intrahepatic IgM anti-HBcAg Fab, as seen in classic AHB, but at variance with ALF; and (vi) higher proportion of antibodies in germline configuration detected by NGS in the intrahepatic antibody repertoire compared to classic AHB, but lower than in ALF. This study identifies distinct outcome-specific features associated with severe AHB caused by a precore HBV mutant in chimpanzees, which bear closer resemblance to HBV ALF than to classic AHB. Our data suggest that precore HBV mutants carry an inherently higher pathogenicity that, in addition to specific host factors, may play a critical role in determining the severity of acute HBV disease.

High Frequency of Either Altered Pre-Core StartCodon or Weakened Kozak Sequence in the CorePromoter Region in Hepatitis B Virus A1 Strainsfrom Rwanda

Hepatitis B virus (HBV) is endemic in Rwanda and is a major etiologic agent for chronic liver disease in the country. In a previous analysis of HBV strains from Rwanda, the S genes of most strains segregated into one single clade of subgenotype, A1. More than half (55%) of the anti-HBe positive individuals were viremic. In this study, 23 complete HBV genomes and the core promoter region (CP) from 18 additional strains were sequenced. Phylogenetic analysis of complete genomes confirmed that most Rwandan strain formed a single unique clade, within subgenotype A1. Strains from 17 of 22 (77%) anti-HBe positive HBV carriers had either mutated the precore start codon (9 strains with either CUG, ACG, UUG, or AAG) or mutations in the Kozak sequence preceding the pre-core start codon (8 strains). These mutually exclusive mutations were also identified in subgenotypes A1 (70/266; 26%), A2 (12/255; 5%), and A3 (26/49; 53%) sequences from the GenBank. The results showed that previous, rarely described HBV variants, expressing little or no HBeAg, are selected in anti-HBe positive subgenotype Al carriers from Rwanda and that mutations reducing HBeAg synthesis might be unique for a particular HBV clade, not just for a specific genotype or subgenotype.

Label Free Quantitative Immunoassay for Hepatitis B

Complementary metal oxide semiconductor (CMOS) technology has already been proven in molecular diagnostics. The present research proved that CMOS image sensor based immunodetection is a suitable diagnostic system for hepatitis B virus antigen (HBV-Ag)-antibody (Ab) interaction. The Ag-Ab was interacted on InNP substrate which was analyzed by a CMOS image sensor by photon number variation. The photon passes through the protein adsorbed substrate and hits the sensor surface. The number of photons attained by the sensor depends on the Ag concentration, nanoparticles size and substrates thickness; therein substrate with higher concentrations of Ag were blocked more photons. The number of photons was detected by the sensor and converted into a digital number with the aid of an analog-to-digital-converter (ADC). A topographical study of AFM and fluorescence images have evaluated the morphological changes, height increment, surface roughness of protein treated and non-treated InNP substrates, to prove the efficiency of CMOS image sensor based immunodetection. Also, the study was compared with conventional ELISA method, to find the sensitivity of CMOS image sensor. Hence, the detection of HBV Ag-Ab interactions by CMOS image sensors is suitable for point-of-care diagnosis.

Immunogenicity of HBV vaccine during stated shelf-life

Thiomersal has been used as preservative in multi-dose vials of hepatitis B vaccine (Engerix-B). Due to safety concerns, thiomersal was replaced with 2-phenoxyethanol (2PE) as preservative in multi-dose vials. The potency of 2PE preserved hepatitis B vaccine multiple use vials was measured over the shelf-life in terms of immunogenicity, reactogenicity and safety. This single-blind, randomized study was conducted with the assistance of employees of GlaxoSmithKline Biologicals, makers of the Engerix-B vaccine. Four hundred twenty subjects aged > or =18 years were randomized to receive three doses (0, 1, 6 months) of 2PE preserved hepatitis B vaccine kept on the shelf <12 months (2PE New group), 2PE preserved hepatitis B vaccine kept on the shelf >18 months (2PE Old group), or thiomersal preserved hepatitis B vaccine [HBV(Thio) group]. Anti-HBs was measured by GlaxoSmithKline Biologicals post-vaccination; the reactogenicity and safety of the vaccines were assessed. Protective anti-HBs levels (> or =10 mIU/ml) were measured one month after dose 3. The results showed protective levels in 86.8% (2PE New), 89% (2PE Old) and 95.3% [HBV(Thio)]. There was no difference detected between the 2PE New and 2PE Old groups in terms of anti-HBs seroprotection rates and geometric mean concentrations one month after dose 3. However, both 2PE groups had significantly lower seroprotection rates than the HBV(Thio) group and the number of non-responders was higher in the 2PE groups than in the Thio group. A antibody response rates over time were similar between the 2PE New and Old groups. The reactogenicity profiles were acceptable and the ranges were similar for each group. The shelf-life of the vaccines had no impact on immunogenicity or reactogenicity and 2PE preserved hepatitis B vaccine can be considered stable over time.

Escalated regimen of hepatitis B vaccine in childhood hematological malignancies while on chemotherapy

This prospective study was conducted to find the effective vaccination schedule against hepatitis B virus (HBV) infection for children with hematological malignancies. Sixty patients ages 2-15 years old with hematological malignancies on chemotherapy, negative for hepatitis B surface antigen (HBsAg) and never vaccinated for HBV before, were vaccinated with 40 microg of vaccine at 0, 1 and 2 months. Antibody titers were measured 6 weeks after administration of last dose. Out of the 60 children enrolled, 5 died during the course of treatment and 4 dropped out before completion, leaving 51 for final analysis. More than 70% exhibited protective levels of antibodies (> 10 mIU/ml) against hepatitis B virus. There were no significant effects of age or sex on the antibody response, although antibodies were higher among girls (90.9%) than boys (65%). Patients with non-Hodgkin's lymphoma were found to exhibit a better antibody response than leukemic children (p = 0.024). Children with hematological cancers should be vaccinated with an escalated regimen of the vaccine.

Immunogenicity and reactogenicity of two recombinant hepatitis B vaccines in small infants: a randomized, double-blind comparative study

Hepatitis B infection is very common in infants, especially in countries with limited resources. Hepatitis B vaccination is recommended in the routine immunization schedules in many countries, including India. We compared immunogenicity and reactogenicity of two recombinant hepatitis B (HB) vaccines in healthy infants. A total of 262 evaluable Indian infants received three doses of 10 microg of an Indian (GeneVac-B) or European (Engerix-B) HB vaccine in a double-blind, randomized fashion. The first dose, given at birth, was followed by a dose at age 6 and 14 weeks. All the subjects were initially seronegative for HB surface antigen (HBsAg) and anti-HB antibodies (anti-HBs). The post-vaccination anti-HBs titers were assessed by ELISA at the time of second and third dose, and 1 month after the third dose. Seroconversion and seroprotection were defined as anti-HBs titers > or =1 mIU/ml and > or =10 mIU/ml, respectively. After first dose, the seroconversion rates were 20% and 17%, in Indian and European vaccine recipients, respectively. The second and third dose increased the seroconversion to 84% and 80%, and to 98% and 98%, respectively. Correspondingly, the seroprotection rates after the first dose was 11% and 10%, and consequently 54% and 58%, and 97% and 95%. None of the differences between vaccines reached statistically significant proportions. Geometric Mean Titer after third dose was 383 mIU/ml and 285 mIU/ml, respectively, also this difference remaining insignificant. Adverse events were similar in both vaccine groups. Immunogenicity and reactogenicity of the Indian and European Hepatitis B vaccines were comparable, when immunization was started at birth.

Viral quasi-species evolution during hepatitis Be antigen seroconversion

BACKGROUND & AIMS

Although viral quasi-species evolution may be related to pathogenesis of disease, little is known about this in hepatitis B virus (HBV); consequently, we aimed to evaluate the evolution of HBV quasi-species in patients with well-characterized clinical phenotypes of chronic hepatitis B.

METHODS

Four cohorts of well-defined clinical phenotypes of chronic hepatitis B, hepatitis Be antigen (HBeAg) seroconverters (spontaneous seroconverters and interferon-induced seroconverters) and nonseroconverters (controls and interferon nonresponders) were followed during 60 months on average. Serum from 4 to 5 time points was used for nested polymerase chain reaction, cloning, and sequencing of the precore/core gene (20 clones/sample). Only patients with genotype B were used. Sequences were aligned using Clustal X, then serial-sample unweighted pair grouping method with arithmetic means phylogenetic trees were constructed using Pebble 1.0 after which maximum likelihood estimates of pairwise distances under a GTR + I + G model was assessed. Viral diversity and substitution rates were then estimated.

RESULTS

Analysis of 3386 sequences showed that HBeAg seroconverters had 2.4-fold higher preseroconversion viral sequence diversity (P = .0183), and 10-fold higher substitution rate (P < .0001) than did nonseroconverters, who had persistently low viral diversity (3.6 x 10(-3) substitutions/site) and substitution rate (2.2 x 10(-5) substitutions x site(-1) x month(-1)). After seroconversion, there was a striking increase in viral diversity. Most seroconverters had viral variants that showed evidence of positive selection, which was seen mainly after seroconversion.

CONCLUSIONS

The high viral diversity before a reduction in HBV DNA and before HBeAg seroconversion could either be related to occurrence of stochastic mutations that lead to a break in immune tolerance or to increased immune reactivity that drives escape mutations.

An hepatitis B virus surface antigen specific single chain of variable fragment derived from a natural immune antigen binding fragment phage display library is specifically internalized by HepG2.2.15 cells

Hepatitis B virus surface antigen (HBsAg), a specific antigen on the membrane of hepatitis B virus (HBV)-infected cells, provides a perfect target for therapeutic drugs. In order to mediate successful targeted delivery of these therapies, it is essential to have antibodies that recognize HBsAg with high specificity and affinity. In this report, we constructed a natural immune antigen binding fragments (Fab) antibody phage display library against HBsAg and after three rounds of panning, five Fab fragments with significant HBsAg binding ability were selected and analysed. DNA sequencing revealed that all the light chains had the same sequence, while all the Fd genes exhibited different sequences. For further application, all of the Fab antibodies were reconstructed into single chain antibodies (scFvs) and expressed in Escherichia coli BL21 cells. Indirect enzyme-linked immunosorbent assay analysis demonstrated that all five scFvs maintained a high affinity for HBsAg and could bind HBsAg on the membrane of HBV-infected cells. Indirect fluorescent staining analysis revealed that one of the scFvs (scFv15) could be internalized into HBsAg-positive HepG2.2.15 cells through clathrin-mediated endocytosis pathway. The internalizing scFv15 antibody would have great potential for the targeted delivery of therapeutics to HBV-infected cells.

[Postoperative safety of liver donors with positive anti-hepatitis B core antibodies for adult to adult living donor liver transplantation]

OBJECTIVE

To evaluate the safety of liver donors with positive anti-HBc for adult to adult living-donor liver transplantation.

METHODS

Between March 2003 and July 2005, 52 donors underwent hepatectomy for living-donor liver transplantation at the West China Hospital. Among them, four were anti-HBc-positive, 48 were anti-HBc-negative. The perioperative clinical profiles of the two groups were compared which included the Hepatitis B indicators, liver functions and growth of liver after operation.

RESULTS

No significant differences were found between the two groups of donors in liver function, hepatitis B indicators, comorbidity, regeneration of remnant livers, and length of stay in hospitals.

CONCLUSION

Anti-HBc-positive donors do not have higher risks than anti-HBc-negative donors for liver transplantation.

Immunogenicity of recombinant hepatitis B vaccine in treatment-naive and treatment-experienced chronic hepatitis C patients: the effect of pegylated interferon plus ribavirin treatment

AIM

To retrospectively evaluate the vaccination-induced anti-HBs seroconversion rates in treatment-naive and treatment-experienced chronic hepatitis C (CHC) patients. Also to prospectively evaluate the seroconversion rates in CHC patients during pegylated interferon (PEG) plus ribavirin (RIB) treatment.

METHODS

Seventy treatment-naive CHC patients (group A), 22 sustained virological responders-SVR following interferon (IFN) plus RIB treatment CHC patients (group B) and 121 healthy subjects (group C) had been participated in the same HBV vaccination schedule (20 microg, 0-1-6 mo). Seroconversion was considered if anti-HBs levels were above 10 mIU/mL within 3 mo following the third dose of the vaccine. Moreover, we prospectively selected 30 non-cirrhotic CHC patients and evaluated them for the efficacy of the same vaccine schedule randomizing them in two groups: Group-1, 15 CHC patients received the first dose of the vaccine in parallel with the initiation of PEG plus RIB treatment and Group-2, 15 patients received the same vaccination schedule without concomitant treatment. Determination of anti-HBs was performed at mo 1, 2, and 7. Statistical analysis of data was based on ANOVA student's t-test and chi-square analysis (P < 0.05).

RESULTS

Fifty-eight of 70 group A patients (82.85%), 20/22 group B (90.9%) and 112/121 healthy subjects (92.56%) had been seroconverted. The seroconversion rates were significantly higher in the control group than in treatment-naive CHC patients (P = 0.04). The corresponding rates were comparable between group A and group B CHC patients (P = 0.38). The vast majority of non-responders (10/14, 71.43%) had been infected by genotype-1 of HCV. The seroconversion rates were comparable between group 1 and 2 CHC patients at mo 1 (20% versus 26.7%, P = 0.67), mo 2 (46.7% vs 60%, P = 0.46) and mo 7 (86.7% versus 93.3%, P = 0.54) of follow-up.

CONCLUSION

The immunogenicity of HBV vaccine seems to be lower in CHC patients compared to healthy subjects. SVR following IFN plus RIB treatment does not affect the antibody response to HBV vaccine. Infection by genotype-1 seems to negatively influence the seroconversion rates. Vaccination against HBV during PEG plus RIB combination treatment is not beneficial in terms of anti-HBs seroconversion rates.

[Adsorption condition optimization for anti-HBsAg Fab fragment separation and purification from E. coli using Streamline SP]

OBJECTIVE

To optimize the adsorption condition of cation-exchange chromatographic media Streamline SP for separation and purification of anti-HBsAg Fab fragment from E. coli.

METHODS

The adsorption of the target protein for separation and purification by the cation-exchange chromatographic media Streamline SP was tested using test tube method in balanced buffer solution with different pH values and ion concentrations. The adsorption effect was then verified by cation-exchange chromatography using 1-ml Streamline SP prepacked column and 28-ml Streamline SP self-assembly column.

RESULTS

According to the experiment results of test tube method, the loading buffer with pH of 4.4 and ionic concentration of 100 to 600 mmol/L could achieve optimal target protein adsorption effect by cation-exchange chromatographic media Streamline SP, as verified by cation-exchange chromatography with 1-ml SP prepacked column and 28-ml Streamline SP self-assembly column.

CONCLUSION

The optimal condition of cation-exchange chromatography selected by test tube method can be applied for separation and purification of anti-HBsAg Fab fragment from E. coli.

Immunization with an adjuvant hepatitis B vaccine in liver transplant recipients: antibody decline and booster vaccination with conventional vaccine

Patients after orthotopic liver transplantation (OLT) due to hepatitis B virus (HBV)-related disease are at risk of endogenous hepatitis B reinfection and may receive life long prophylaxis with hepatitis B hyperimmunoglobulin (HBIG). In a previous study 16 of 20 OLT patients were immunized successfully with an adjuvant hepatitis B vaccine. To maintain protective antibody levels under immunosuppressive therapy, 11 of these patients were revaccinated with a double dosed conventional hepatitis B vaccine. Median interval between last vaccination and booster was 24 months (range 22-31 months). Antibody titres against hepatitis B surface antigen (anti-HBs) were monitored at the day of booster vaccination (day 0), at day 7 and day 28. At day 0, all vaccinees but one had anti-HBs titres greater than 500 IU/L (median 1,925 IU/L, range 196-7,612 IU/L). Maximum antibody titres after previous vaccination declined by a median of 82% (range 47-96%). After booster vaccination the anti-HBs titre increased significantly by a median factor of 2.42 (P<0.05). In conclusion, the majority of liver transplant recipients who previously had responded to adjuvant hepatitis B vaccine exhibited sufficient immunocompetence to produce a substantial antibody response after booster immunization with a conventional vaccine.

Cloning, expression and identification of the gene of human single-chain variable fragment antibody against Hepatitis B virus surface antigen

Expression of single-chain variable fragment (scFv) antibodies on the surface of bacteriophage is widely used to prepare antibodies with pre-defined specificities. A phage antibody library containing the gene for scFv antibody against Hepatitis B virus surface antigen (HBsAg) was panned with HBsAg immobilized on microtiter plate wells. After five rounds of panning 30 phage clones specific to HBsAg were obtained and one selected clone was sequenced. It was found to consist of 789 bp and its amino acid sequence and specifically detected the respective antigen in the patients but not in healthy persons.

Formation of vesicular stomatitis virus pseudotypes bearing surface proteins of hepatitis B virus

It has been difficult to propagate and titrate hepatitis B virus (HBV) in tissue culture. We examined whether vesicular stomatitis virus (VSV) pseudotypes bearing HBV surface (HBs) proteins infectious for human cell lines could be prepared. For this, expression plasmids for three surface proteins, L, M, and S, of HBV were made. 293T cells were then transfected with these plasmids either individually or in different combinations. 293T cells expressing HBs proteins were infected with VSVdeltaG*-G, a recombinant VSV expressing green fluorescent protein (GFP), to make VSV pseudotypes. Culture supernatants together with cells were harvested and sonicated for a short time. The infectivities of freshly harvested supernatants were determined by quantifying the number of cells expressing GFP after neutralization with anti-VSV serum and mouse monoclonal antibodies (MAbs) against HBs protein. Among 14 cell lines tested for susceptibility to HBV pseudotype samples, HepG2, JHH-7, and 293T cells were judged to be the most susceptible. Namely, the infectious units (IU) of the culture supernatant samples neutralized with anti-VSV in the absence and presence of anti-HBs S MAbs and titrated on HepG2 cells ranged from 1,000 to 4,000 IU/ml and 200 to 400 IU/ml, respectively, suggesting the presence of VSVdeltaG*(HBV) pseudotypes. This infectivity was inhibited by treatment with lactoferrin or dextran sulfate. Pretreatment of the cells with trypsin or tunicamycin inhibited plating of the pseudotype samples. The HBV pseudotypes can be used to analyze early steps of HBV infection, including the entry mechanism of HBV.

Fatal reactivation of hepatitis B post-chemotherapy for lymphoma in a hepatitis B surface antigen-negative, hepatitis B core antibody-positive patient: potential implications for future prophylaxis recommendations

In the absence of prophylaxis, the reactivation of hepatitis B in oncology patients who are hepatitis B carriers is a well-known and often fatal complication of chemotherapy. The current recommendations in Canada and the USA are that patients who are positive for hepatitis B surface antigen (HBsAg) receive antiviral prophylaxis prior to chemotherapy. We report a 67-year-old man with B-cell lymphoma who developed hepatitis B reactivation following chemotherapy with cyclophosphamide, adriamycin, vincristine, prednisone and rituximab. Pre-chemotherapy, the patient was negative for HBsAg, positive for hepatitis B core antibody (anti-HBc) and weakly positive for hepatitis B surface antibody. Despite treatment with lamivudine, the patient died of fulminant hepatic failure. Our experience indicates that patients who are negative for HBsAg but positive for anti-HBc are still at risk for reactivation of latent hepatitis B during and after chemotherapy and may be considered for prophylaxis.

Hepatitis B Core Antibody Positive Donors as a Safe and Effective Therapeutic Option to Increase Available Organs for Lung Transplantation

BACKGROUND

The use of hepatitis B core antibody (HBcAb+) and hepatitis C antibody (HCV Ab+) positive donors represents one strategy to increase available donor organs, but this remains controversial because of concern for viral transmission to recipients. We hypothesized that isolated HBcAb+ donors represent minimal risk of viral transmission in vaccinated lung transplant (LTx) recipients.

METHODS

A retrospective study was performed of LTx recipients who received HBcAb+ or HCV Ab+ pulmonary allografts. We analyzed liver function studies, viral hepatitis screening tests, quantitative polymerase chain reaction for hepatitis B viral DNA (HBV DNA) and hepatitis C viral RNA (HCV RNA), freedom from bronchiolitis obliterans syndrome, acute rejection, and survival.

RESULTS

Between April 1992 and August 2003, 456 LTx operations were performed. Twenty-nine patients (HB group) received HBcAb+ allograft transplants with a median posttransplant follow-up of 24.5 months. Three critically ill patients (HC group) received HCV Ab+ allografts with a median follow-up of 21.5 months. One-year survival for the HB group is 83% versus 82% for all patients who received non-HB organs (P=0.36). No patient in the HB group developed clinical liver disease because of viral hepatitis, and all patients alive (n=21) at follow-up are, to date, HBV DNA and/or HBcAb negative. All patients in the HC group tested HCV RNA positive; one patient died of liver failure at 22 months.

CONCLUSIONS

Risk of viral transmission with HCV Ab+ allografts seems high after LTx. However, the use of HBcAb+ pulmonary allografts in recipients with prior hepatitis B vaccination seems to be a safe and effective strategy to increase organ availability.

An outbreak of fulminant hepatitis B in immunocompromised hemodialysis patients

BACKGROUND

We aimed to clarify the pathogenesis of an outbreak of fulminant hepatitis B in hemodialysis (HD) patients whose compromised cell-mediated immunity in turn contributed to chronic hepatitis B virus (HBV) carriage.

METHODS

Five consecutive adult HD patients with acute hepatitis B were evaluated. Viral genotype, mutations, and HBV-DNA levels were studied in relation to viral clearance, liver disease severity, and liver histology by immunostaining.

RESULTS

All five patients had hepatitis B surface antigen (HBsAg) genotype C, a G-to-A stop codon mutation at nucleotide (nt) 1896 in the precore region, an A-to-T mutation at nt 1762 and an G-to-A mutation at nt 1764 in the basal core promoter. The possible index patient, who suffered from liver cirrhosis, had HBsAg genotype C, anti-hepatitis B envelope (HBe), and these mutations. The level of HBV-DNA declined by about 10 percent per week and no difference in viral kinetics between the patients who died and the survivor was found, irrespective of therapies. The amount of liver cell apoptosis, as assessed by single-stranded DNA, was scarce. The risk of fulminant hepatic failure did not correlate with the preexistent liver histopathological changes. Acute HBV superinfection was associated with hepatitis C virus (HCV) elimination and increased mortality.

CONCLUSIONS

This outbreak of fulminant hepatitis B suggests that HD patients can foster highly virulent HBV strains (possibly owing to their compromised immune responses), which may place others at risk of severe, life-threatening acute liver damage and at increased risk of mortality if chronic carriers of HCV should be infected. We aimed to clarify the pathogenesis of an outbreak of fulminant hepatitis B in hemodialysis (HD) patients whose compromised cell-mediated immunity in turn contributed to chronic hepatitis B virus (HBV) carriage.

[HBsAg uptake into human trophoblasts cultured in vitro]

OBJECTIVE

To detect the entry of HBsAg into human trophoblasts cultured in vitro, to provide some clues for the mechanism responsible for HBV intrauterine transmission.

METHODS

Digestion with both trypsin (0.25%) and Dnase I(0.15 U/ml) followed by repeated purification was performed to obtain a homogeneous population of trophoblast cells. The well-developed cells during longitudinal phase were randomly divided in 6 groups, which were co-incubated respectively with HBsAg-anti-HBs complex (I), co-culture of heat-inactivated sera positive for HBsAg, HBeAg, and anti-HBc and sera with high titer anti-HBs(II), heat-inactivated sera positive for HBsAg, HBeAg, and anti-HBc(III), HBsAg (IV), heat-inactivated normal sera (V), and normal medium(VI). The coverglasses mounted with confluent cells were harvested for anti-HBs immunohistochemical staining.

RESULTS

The isolated cells comprised a highly purified villous trophoblast population and could meet the demands of further experiments. After co-incubation of the cells with different agents, HBsAg test yielded positive results in the cells co-incubated with the HBsAg-anti-HBs complex and in the co-cultures of heat-inactivated sera positive for HBsAg, HBeAg and anti-HBc with sera containing high-titer anti-HBs. HBsAg test was negative in all other cell groups.

CONCLUSION

Human trophoblast cells could take in HBsAg in the form of HBsAg-anti-HBs complex instead of single HBsAg molecule.

Transplantation of livers from hbc Ab positive donors into HBc Ab negative recipients: a strategy and preliminary results

Here we describe a strategy for using livers from hepatitis B core antibody (anti-HBc) positive donors in anti-HBc negative recipients and report our preliminary results. Adult anti-HBc negative recipients were immunized against hepatitis B virus (HBV) prior to transplantation. Liver biopsies from anti-HBc positive, HBs Ag negative donors were performed at the time of procurement to rule out acute hepatitis or chronic liver disease. Donor serum and liver samples were collected for HBV DNA analysis by PCR. Recipients were given HBIG (10000 units, i.v.) during the anhepatic phase of transplantation. Patients were treated with lamivudine (150 mg) beginning on postoperative day (POD) 1. If HBV DNA was not detected in either donor liver or serum by PCR, recipient antiviral therapy was stopped. If donor liver and serum were positive for HBV DNA by PCR, the recipient was maintained on combination lamivudine and HBIG therapy. If HBV DNA was detected in donor liver but not in donor serum, the patient was managed on lamivudine therapy alone. Between February 1999 and June 2000, six anti-HBc negative recipients received liver transplants from anti-HBc positive donors. PCR analysis of serum from the six donors was negative for HBV DNA in each, while donor liver PCR analysis was positive in five of six for HBV DNA. Accordingly, all patients were given HBIG in the anhepatic phase of transplantation and five of six were maintained on daily lamivudine therapy. Follow-up periods have ranged from 2 to 18 months. There has been no emergence of de novo hepatitis B. Serial serum HBs Ag and HBV DNA assays have all proven negative. Moreover, while on lamivudine therapy, 2 patients now have undetectable HBV DNA in hepatic allograft biopsies by PCR analysis. Our strategy for using livers from anti-HBc donors has yielded promising initial results. De novo hepatitis B has not occurred and our data suggest residual hepatitis B virus may be eradicated in recipients maintained on lamivudine therapy.

Characterization and diagnostic potential of hepatitis B virus nucleocapsid expressed in E. coli and P. pastoris

The hepatitis B core antigen (HBcAg) was expressed in Escherichia coli and in Pichia pastoris. A hexahistidine tag was introduced at the C terminus of the E. coli expressed protein allowing its purification by Ni(2+)-chelate affinity chromatography. The P. pastoris expressed HBcAg was isolated following heat treatment. The two recombinant HBcAgs were purified further on a sucrose gradient. Mass spectrometry analysis suggested that HBcAg was N-acetylated only in P. pastoris and reaction with Ellman's reagent allowed the measurement respectively, of 0.37 and 0.23 mole of free sulfydryl groups per mole of HBcAg monomer expressed in E. coli or P. pastoris. Electron microscopy indicated that the E. coli and the P. pastoris proteins formed capsid-like particles with respectively, a diameter of 34 and 28-nm. Nucleic acid components were found entrapped in both particles but protected from enzymatic treatment only in the P. pastoris derived particles suggesting structural discrepancies between the two recombinant molecules. The high purity of these recombinant antigens allowed the development of a sandwich immunoassay to detect anti-HBc antibodies in human serum. The preliminary results indicate that the P. pastoris HBcAg produced intracellularly is more suitable than the renatured E. coli HBcAg for detection of anti-HBc in this diagnostic assay.

Anti-HBs after hepatitis B immunization with plasma-derived and recombinant DNA-derived vaccines: binding to mutant HBsAg

The G145R mutant of the small S-protein is a major escape mutant of hepatitis B virus observed in natural infection, after immunization and HBIG therapy. In a previous study we found that plasma-derived and recombinant DNA-derived vaccine HBsAg reacted differently with monoclonal antibodies sensitive for the G145R change. In the present study we investigated the binding of polyclonal anti-HBs obtained after immunization with plasma vaccine and recombinant DNA vaccine to synthetic peptides (adw(2), adr) and rHBsAg (HepG2) (ayw(3); wild type and a 145R mutant). Anti-HBs binding to synthetic peptids (25-mers, 7aa overlap) from the "a"-loop was significantly reduced by the G145R substitution and by changing the amino acid sequence from adw(2) into adr. With mutant G145R rHBsAg the inhibitory activity of vaccine anti-HBs was decreased compared to rHBsAg wild type. In general only minor differences were observed between plasma vaccine and recombinant DNA vaccine related antibody responses. However, the individual heterogeneity in epitope specific reactivity with its possible consequences for protection (against escape mutants) is not reflected in an anti-HBs titer by standard anti-HBs assays. The presented differentiation in anti-HBs response after immunization may deliver new tools for evaluation of future vaccines.

Transmission of hepatitis B infection from hepatitis B core antibody--positive liver allografts is prevented by lamivudine therapy

Donor shortage has led to the use of hepatitis B core antibody (anti-HBc)--positive (anti-HBc(+)) liver allografts for patients in need of relatively urgent orthotopic liver transplantation (OLT). Because anti-HBc(+) allografts transmit hepatitis B virus (HBV) infection at a high rate, effective prophylaxis is required. We assessed the effectiveness of lamivudine in preventing HBV transmission by anti-HBc(+) allografts. Between March 1996 and March 2000 at Cedars-Sinai Medical Center (Los Angeles, CA), 15 of 169 patients (8.9%) received liver allografts from anti-HBc(+) donors. Six patients were hepatitis B surface antigen (HBsAg)(+) (group 1), and 9 patients were HBsAg negative (HBsAg(-); group 2) before OLT. All patients were administered lamivudine, 100 or 150 mg/d, orally after OLT. Patients who were HBsAg(+) before OLT also were administered hepatitis B immunoglobulin (HBIG) prophylaxis. Hepatitis B serological tests were performed on all patients, and HBV DNA was determined in liver tissues in 10 patients. All 15 patients remained HBsAg(-) at their last follow-up 2 to 40 months (mean, 17 months) post-OLT. All patients in group 1 had antibody to HBsAg (anti-HBs) titers greater than 250 mIU/mL post-OLT (mean follow-up, 20 months; range, 7 to 40 months). Of the 2 patients in group 1 who underwent liver biopsy after OLT, 1 patient had detectable hepatic HBV DNA despite being anti-HBs(+) and HBsAg(-). Among the patients in group 2, none acquired anti-HBc or HBsAg. Hepatic HBV DNA was undetectable in the 7 patients in group 2 who underwent liver biopsy after OLT. Anti-HBc(+) allografts can be safely used in patients who undergo OLT for chronic hepatitis B and susceptible transplant recipients if prophylaxis with combination HBIG and lamivudine or lamividine alone is administered after OLT, respectively. However, more data are needed to determine the efficacy of lamivudine monotherapy in preventing transmission of HBV infection from anti-HBc(+) liver allografts to susceptible recipients.

Immunostimulatory sequence up-modulate the interaction between immunoglobulins and plasmid DNA at acidic pH

To identify specific receptors for immunostimulatory sequence (ISS), a cDNA library of human bone marrow was screened by one-hybrid system using ISS as bait. Among four duel-positive clones isolated so far, two encode light chain of immunoglobulin (Ig) homologous to anti-DNA and anti-HBsAg (HBsAb), respectively, suggesting a direct interaction between ISS and Igs. ELISA revealed that HBsAb, as well as Igs in normal mouse serum and a monoclonal anti-v5 antibody, bound to plasmid DNA in a pH-dependent way; more importantly, the plasmids inserted with more copies of ISS shown higher reactivity with these Igs than their blank vectors. Electrophoretic mobility shift assay (EMSA) showed HBsAb bound to oligonucleotides (ODN) also in a pH-dependent and ISS-specific way. Furthermore, ISS-containing ODN could enhance the binding of Igs to plasmid DNA at acidic pH. These results support existence of direct ISS-Ig interaction and demonstrated that DNA-Ig interaction could be up-modulated by ISS. In consideration of the crucial role of membrane Ig (mIg) in B cell activation, these results suggest mIg may be a candidate ISS receptor in ISS-induced B cell activation.

Targeting murine immune responses to selected T cell- or antibody-defined determinants of the hepatitis B surface antigen by plasmid DNA vaccines encoding chimeric antigen

By exchanging sequences from the middle-surface (MS) and small-surface (S) Ag of hepatitis B virus (HBV) with corresponding sequences of the MS Ag of woodchuck hepatitis virus, we constructed chimeric MS variants. Using these constructs as DNA vaccines in mice, we selectively primed highly specific (non-cross-reactive) Ab responses to pre-S2 of the HBV MS Ag and the "a" determinant of the HBV S Ag, as well as L(d)- or K(b)-restricted CTL responses to HBV S epitopes. In transgenic mice that constitutively express large amounts of HBV surface Ag in the liver we could successfully suppress serum antigenemia (but not Ag production in the liver) by adoptive transfer of anti-pre-S2 or anti-"a" immunity but not CTL immunity. DNA vaccines greatly facilitate construction of chimeric fusion Ags that efficiently prime specific, high-affinity Ab and CTL responses. Such vaccines, in which sequences of an Ag of interest are exchanged between different but related viruses, are interesting tools for focusing humoral or cellular immunity on selected antigenic determinants and elucidating their biological role.

Can hepatitis B core antibody positive livers be used safely for transplantation: hepatitis B virus detection in the liver of individuals who are hepatitis B core antibody positive

A major impediment to the wider application of clinical liver transplantation is the paucity of acceptable organs. Most centers refuse organs that come from donors who are hepatitis B core antibody positive because of a fear of transmission of hepatitis B virus (HBV) infection to the recipient. The risk related to the use of such donor organs has never been assessed in an ordered manner. The presence or absence of polymerase chain reaction detectable HBV-DNA in liver tissue of individuals undergoing liver biopsy for clinical reasons was assessed in 133 consecutive patients. A total of 8.2% of these livers resulted positive for HBV-DNA; interestingly the rate was higher among those who were hepatitis B surface antibody positive (12.5%) as compared to those without detectable hepatitis B surface antibody (5.7%). These data provide measures of putative risk for HBV infection in liver transplant recipients associated with the use of organs obtained from a hepatitis B core antibody positive donor.

A mathematical model predicting anti-hepatitis B virus surface antigen (HBs) decay after vaccination against hepatitis B

The determination of serum levels of antibodies against hepatitis B virus surface antigen (anti-HBs) after hepatitis B vaccination is currently the only simple test available to predict the decay of protection and to plan the administration of booster doses. A total of 3085 vaccine recipients of plasma-derived and recombinant vaccine have been followed for 10 years to determine the kinetics of anti-HBs production and to construct a mathematical model which could efficiently predict the anti-HBs level decline. The anti-HBs peak level was reached 68 days after the last dose of recombinant vaccine and 138 days after the last dose of plasma-derived vaccines. The age of vaccinees negatively influenced the anti-HBs levels and also the time necessary to reach the anti-HBs peak. A bilogarithmic mathematical model (log10 level, log10 time) of anti-HBs decay has been constructed on a sample of recombinant vaccine recipients and subsequently validated on different samples of recombinant or plasma-derived vaccine recipients. Age, gender, type of vaccine (recombinant or plasma-derived), number of vaccine doses (three or four) did not influence the mathematical model of antibody decay. The program can be downloaded at the site: http:@www2.stat.unibo.it/palareti/vaccine.htm . Introducing an anti-HBs determination obtained after the peak, the program calculates a prediction of individual anti-HBs decline and allows planning of an efficient booster policy.

Comparison of immune reactivity and pharmacokinetics of two hepatitis B immune globulins in patients after liver transplantation

Hepatitis B virus (HBV) immune globulin (HBIg) administration will prevent HBV graft reinfection in HBV patients after orthotopic liver transplantation (OLT). However, the expenditure for such prophylaxis is extremely high ranging between $2,000 to $10,000 per month in various countries for an undefined period and presumably for life. As a consequence, there is a need for introduction of additional and less expensive modes of treatment. In a preliminary clinical trial a new HBIg preparation has been shown to induce longer lasting levels of circulating antibodies to hepatitis B surface antigen (anti-HBs) in patients after OLT compared with previous experience with conventional HBIg preparations. In the present study the pharmacokinetics of this new HBIg, OMRI-Hep-B, were studied and compared with a conventional, licensed preparation, Hepatect. Fifteen post-OLT patients (2-8 years post-OLT, 18-62 years of age, 6 men, 9 women) were treated intravenously with 49 doses of OMRI-Hep-B or Hepatect given at least once, alternately, at 10,000 to 14,000 units per injection ( approximately 130 IU/kg body weight). The new HBIg was well tolerated and no adverse effects were observed. Administration of OMRI-Hep-B was shown to induce high and long-lasting levels of circulating anti-HBs antibodies and greater areas under the curve (AUC) compared with the conventional preparation. Thus, anti-HBs half-life was 22 +/- 1.3 days for OMRI-Hep-B recipients and 13 +/- 1.3 days for Hepatect recipients (P <.001). Time to reach trough anti-HBs levels of 150 mIU/mL was significantly longer after administration of OMRI-Hep-B than after Hepatect (79 +/- 4.5 and 52 +/- 3.8 days, respectively; P <.001). In summary, the pharmacokinetic profile of the new HBIg, and in particular its prolonged elimination half-life, may reduce the cost of administration by approximately 30% and improve the quality of life of patients by extending the interval between repeated immune globulin injections.

Use of PCR in resolving diagnostic difficulties potentially caused by genetic variation of hepatitis B virus

AIMS

To assess the relevance of genetic variants of hepatitis B virus (HBV) and to demonstrate the usefulness of the polymerase chain reaction (PCR) in cases of HBV diagnostic difficulty.

METHODS

Five serum samples from patients that presented diagnostic difficulty in routine laboratories were sent to a research laboratory for PCR, and if appropriate, S gene sequencing, in vitro expression, and antigenic analysis.

RESULTS

The demonstration of HBV in serum by PCR allowed a definitive diagnosis of current infection. One serum sample with poor reactivity in a diagnostic assay had a minor hepatitis B surface antigen (HBsAg) variant and another with very poor reactivity had multiple variants of HBsAg. Transient HBsAg reactivity was observed in a recently vaccinated patient. A hepatitis Be antigen (HBeAg) false positive reaction was noted in a patient from a well defined risk group for HBV. One patient who was strongly HBsAg/HBeAg positive, but anti-hepatitis B core antibody negative, was viraemic.

CONCLUSIONS

PCR may become the gold standard for the diagnosis of current HBV infection. HBV variants are responsible for a proportion of diagnostically difficult cases. Modification of commercial assays is necessary to increase the sensitivity of detection of such variants.

Intravenous or intramuscular anti-HBs immunoglobulin for the prevention of hepatitis B reinfection after orthotopic liver transplantation

To prevent reinfection with hepatitis B virus after orthotopic liver transplantation, patients receive long-term intravenous anti-HBs immunoprophylaxis. We compared the pharmacokinetics of intravenously and intramuscularly administered commercially available hepatitis B virus immunoglobulins. The study group consisted of 12 patients on immunoprophylaxis after orthotopic liver transplantation, who were Hbs antigen negative; 11 were anti-HBe positive and one was HBe positive. The patients first received intravenous immunoglobulin, and six of them were then transferred to intramuscular immunoglobulin. Our findings show that with fortnightly intramuscular application of 1000 IU of anti-HBs, reproducible and stable antibody titers above 100 IU of anti-HBs can be achieved. Side effects of intramuscular immunoprophylaxis are minimal and the method is safe. The switch from intravenous (1500 IU of anti-HBs) to intramuscular (1000 IU of anti-HBs) reduced the cost of immunoprophylaxis by more than 50%.

Maltodextrin-binding protein hybrids carrying epitopes from the preS2 region of hepatitis B virus: expression, antibody-binding and preliminary crystallographic studies

Five hybrid constructions of maltodextrin-binding protein (MBP), each containing an inserted epitope(s) from the preS2 region of the envelope proteins of hepatitis B virus (HBV), have been expressed. The anti-preS2 monoclonal antibody S2.3 was shown to cross-react with the MBP hybrid constructions, demonstrating that the epitopes presented by these recombinant proteins mimic the antigenic behaviour of the native viral antigen. In addition, all five hybrid proteins have been crystallized. Preliminary structural solutions obtained by molecular replacement indicate that the native conformation of MBP is preserved in the hybrid constructions despite the significant length of the epitope insertions.

Persistence of anti-HBs in children vaccinated against viral hepatitis B in the first year of life: follow-up at 5 and 10 years

The persistence of anti-HBs protective levels in groups of children who had been immunized against Hepatitis B 5 and 10 years earlier, in their first year of life, has been studied. The results were analyzed according to the type of vaccine (both plasma-derived and DNA recombinant) and the number of doses administered (three or four doses). In addition, the protective effect of the vaccine in vaccinated subjects was studied in relation to the anti-HBc presence. The serologic results suggest that, in cohorts of children vaccinated 5 years earlier, a higher prevalence of subjects with anti-HBs protective levels was found, when the DNA recombinant vaccines were administered (97.6% for MSD Recombivax and 97.1% for SKF Engerix B); a lower one when the plasma-derived vaccine was used (80.4% Pasteur Merieux, Hevac B). Moreover, in cohorts of children vaccinated with plasma derived vaccine (hevac B) 10 years earlier, a higher prevalence of subjects with anti-HBs protective levels was demonstrated when four doses were administered (76.9%); a lower one when three doses were inoculated (57.5%). The absence of core antibody (anti-HBc) in responders to the vaccination shows the protective efficacy of both the DNA recombinant and plasma derived vaccines. On the other hand the presence of anti-HBc in some anti-HBs negative non-responders subjects shows the susceptibility of these people to infection. In anti-HBs negative vaccinated subjects the appearance of levels of anti-HBs in 95.9% of subjects, 1 week after the administration of a booster dose, demonstrates the presence of a solid immunologic memory.

Highly specific, cross-reactive sequences recognized by an anti-HBsAg antibody identified from a positional scanning synthetic combinatorial library

The binding specificity of a monoclonal antibody (MAb 12) known to recognize the surface antigen of hepatitis B virus (HBsAg) was studied using a positional scanning synthetic combinatorial library. A hexapeptide library totaling more than 30 x 10(6) sequences, made up of 120 mixtures having a single position defined with individual amino acids and the remaining five positions composed of mixtures of amino acids, was screened by competitive enzyme-linked immunosorbent assay (ELISA). This led to the identification of Ac-STTSMM-NH2 (IC50 = 170 nM), which specifically inhibited the interaction between HBsAg and MAb 12. One of the most active individual mixtures from the library was Ac-XXXPXX-NH2; however, none of the individual peptides synthesized containing proline at the fourth position showed significant activity (IC50 > 100,000 nM). To identify the individual peptide(s) responsible for the activity of Ac-XXXPXX-NH2, a bidirectional iterative synthesis and selection process was carried out. A completely different but active peptide sequence was identified (Ac-SVGPPH-NH2, IC50 = 165 nM). The two different hexapeptide sequences were prepared as linear homo- and heterodimer peptides in an attempt to improve the antigenicity. Of the four different sequences prepared, one heterodimer (Ac-STTSMMGGGSVGPPH-NH2) was found by ELISA to have a 10-fold improvement in activity over the two individual hexapeptides, and was equal to the inhibitory activity of the protein antigen. The equilibrium affinity constant of the MAb 12 toward this heterodimer sequence was 50-fold higher than the protein antigen when measured in a biosensor system. Since motifs from these two hexapeptides, namely, -STTS- and -GP-, were located in the primary sequence of the protein (residues 114-120, subtype ad), overlapping hexapeptides of this region were synthesized and assayed. The most active hexapeptide, namely, Ac-TTSTGP-NH2 (IC50 = 2.3 microM), was 10-fold less active than either hexapeptide found from the library. Extending the specific motif sequences to eleven residues resulted in an analog (Ac-STTSTGPSRTC-NH2) having an equilibrium affinity constant similar to the heterodimer. The combined use of positional scanning libraries and the iterative synthesis and selection process in this study illustrates the power of these methods for the identification of novel peptides that inhibit anti-protein antibodies. These methods can be directly applied to the development of improved immunodiagnostics.

Tumor necrosis factor receptors in patients with chronic hepatitis B virus infection

BACKGROUND/AIMS

Patients with chronic hepatitis B infection have elevated plasma tumor necrosis factor (TNF) alpha levels. Two TNF-alpha receptors have been identified, each responsible for distinct TNF-alpha activities. The aim of this study was to evaluate the biological function of the elevated TNF-alpha in chronic hepatitis B virus infection by examining the two TNF signaling pathways in the evolution of hepatitis B-related liver injury.

METHODS

The hepatic expression of the two TNF receptors and the corresponding serum levels of the soluble forms of both TNF receptors were determined and correlated with hepatic inflammation and virus replication in 98 chronic hepatitis B surface antigen carriers. Forty hepatitis B e antigen-positive patients were also studied prospectively, while on interferon alfa treatment, to examine the TNF receptor response during viral clearance.

RESULTS

In chronic hepatitis B virus infection, the hepatic expression and serum levels of TNF receptors, in particular 75-kilodalton TNF receptor subtype (TNF-R p75), are significantly enhanced in association with hepatic inflammation and hepatocytolysis but not with hepatitis B virus replication. During interferon alfa treatment, a significant increase of soluble TNF-R p75 always precedes the hepatitis B e antigen antibody against hepatitis B e antigen seroconversion in responders to treatment.

CONCLUSIONS

In chronic active hepatitis B infection, there is an up-regulation of the TNF receptor system, preferentially the TNF-R p75 signaling pathway, which suggests that the TNF-alpha/TNF receptor system has an important role in the pathogenesis of liver damage and viral clearance.

[Investigation on change of acquired antibodies in responders against hepatitis B vaccine]

Changes of titers of acquired hepatitis B surface (HBs) antibodies against HB vaccine were investigated by measuring them again after a long lapse of time. Ten micrograms of the recombinant HB vaccine was intramuscularly injected respectively to the staff of the authors' hospital three times. Four weeks after a full course of the vaccination 185 persons could acquire antibodies, whose titers were 2.0 or more in cut off index (C.I.) by radioimmunoassay (RIA). Of these members titers of antibodies of 48 subjects could be remeasured for the first time 38 months after the measurement of the titers in the 4th week after a full course of the vaccination. Four weeks after the last vaccination 7 persons were high responders whose titers of antibodies were 50 or more in C.I. 29 were medium responders with their titers from 49 to 10, and 12 were low responders having titers of less than 10. However, 38 months after the course the titers of those responders decreased so much that nobody remained highly responders, 22 were low responders, and the remaining 22 turned to be negative again with titers less than 2.0. Supposing that the titer of antibody enough to protect the infection of HB virus is 10 or more in C.I., 32 of 36 persons needed booster shots 38 months later because their titers dwindled down to less than 10.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis B virus carrier with low titer of antibody to hepatitis B core antigen

Of 798 hepatitis B virus (HBV) carriers, 22 had low titers (lower than 80% inhibition in 200- or 400-fold diluted serum) of antibody to hepatitis B core antigen (anti-HBc). Among these 22 patients, there were 12 (1.50%) with viremia who were positive for hepatitis B e antigen and had a high titer of HBV-associated DNA polymerase activity. Among these 12 patients, four showed no significant change in the anti-HBc titer, while four others showed significant increases in the anti-HBc titer during the follow-up periods. The former all remained asymptomatic carriers (ASCs), while the latter all developed chronic hepatitis (CH). The liver histology of four patients (ASC: 2, CH: 2) showed mild inflammation, and the localization of hepatitis B core antigen (HBcAg) in the liver specimens showed a nuclear pattern in the two ASCs, but a nuclear plus cytoplasmic pattern in the two CH cases. In HBV carriers, the increase in anti-HBc titer seems to be closely correlated to the change in HBcAg localization from the nucleus to the cytoplasm in the liver. Therefore, rising titers of anti-HBc were assumed to be associated with increased expression of HBcAg on the hepatocyte, and hence increased immune-mediated hepatic damage and the onset of hepatitis in ASC with low titer of anti-HBc.

Anti-HBs antibody kinetics--a 4-year follow-up after hepatitis B vaccination

To describe anti-HBs kinetics after hepatitis B vaccination, a logarithmic function was established using anti-HBs determinations in sera drawn from 97 to 147 vaccinees at 5 times during a 4 year follow-up period. A comparison with 2 published mathematical models showed that the logarithmic formula was less complex, and computed values correlated better with real anti-HBs titres.

PreS antigen expression and anti-preS response in hepatitis B virus infections: relationship to serum HBV-DNA, intrahepatic HBcAg, liver damage and specific T-cell response

The diagnostic value of preS antigens and anti-preS antibodies during Hepatitis B virus (HBV) infections have not yet been clearly elucidated. Therefore, the objectives of this study were: 1) to better understand the clinical significance of the expression of both preS1 and preS2 antigens (preS1Ag and preS2Ag) in the serum of chronic HBsAg carriers, and 2) to define the respective role of antibody responses to HBs-, preS2- and preS1-specific determinants in the course of acute hepatitis B (AH-B) infections with different outcomes. Our data showed that the serum preS1Ag/HBsAg ratio correlated well with the level of viral replication (serum HBV-DNA as monitored by PCR assay and liver HBcAg), especially in anti-HBe positive chronic carriers. The complete eradication of virions required a persistent antibody response to conformation-dependent HBs-epitopes, temporally associated with a vigorous T cell response to nucleocapsid antigens. Recovery from hepatitis B can be achieved when there is no early antibody response to preS2- and preS1-proteins, which was found to be transient, concomitant with a flare-up of the liver disease, and preceding anti-HBs production. Information on the patterns of preS antigens and their antibodies remained clouded because of the varying specificities and sensitivities of research methods used in studies to date. We have, therefore, developed original Polyclonal-Monoclonal RadioImmunoAssays (PAb-MAb RIAs) by using monoclonal antibodies (MAbs) having previously well-defined specificities. We could thus detect and quantify simultaneously the three distinct antigenicities of the HBV envelope, HBsAg, preS2Ag and preS1Ag, with the same sensitivity. In this way, the preS1Ag/HBsAg and preS2Ag/HBsAg ratios can be calculated to estimate the serum expression of both preS1Ag and preS2Ag in relation to total HBsAg activity during different stages of chronic HBV infection. For optimal management of the state of HBV replication in chronic viral infection, the detection of HBV-DNA in serum was monitored by the Polymerase Chain Reaction (PCR) assay. We extended our work by investigating the clinical significance of antibody response to preS-specific determinants in patients with AH-B showing different outcomes in both natural course or response to alpha-interferon therapy. In a first attempt, we chose to use the Western Immuno-Blotting Assay (WIBA) to obtain a qualitative assessment of the nature of preS antibody responses. Finally, the cell-mediated immune response to HBV antigens was also studied in several patients with self-limited AH-B leading to a relevant finding which may help to clarify the mechanisms responsible for complete clearance of HBV.

Defective immune adherence and elimination of hepatitis B surface antigen/antibody complexes in patients with mixed essential cryoglobulinemia type II

Mixed essential cryoglobulinemia type II (monoclonal Ig/polyclonal IgG) is characterized by systemic vasculitis caused by the deposition of circulating immune reactants that include the monoclonal component. Such reactants may include immune complexes (IC) formed from exogenous Ag. IC binding to E C receptor type 1 appears to play a role in transport and buffering of such IC (immune adherence: IA). To define the mechanisms responsible for immune deposition, 7 patients with cryoglobulinemia type II (IgM kappa/polyclonal IgG) and 14 normal volunteers were injected i.v. with hepatitis B surface Ag/antibody complexes. Two minutes after injection, only 19.4% (mean) of the circulating complexes were bound to E in patients as compared with 63.1% in normal subjects. This IA correlated directly with C4 and inversely with the IgM rheumatoid factor (RF) titer. Disappearance of IC was faster in patients (mean elimination rate: 15.7%/min) than in normal subjects (9.3%). In vitro experiments demonstrated that C depletion, interference with IC opsonization by monoclonal IgM RF, and decreased binding of opsonized IC in the presence of monoclonal RF are each associated with decreased IA. These observations suggest that, in patients with cryoglobulinemia type II, monoclonal IgM RF and low C contribute to reducing IA of circulating IC that might be rapidly trapped in tissues, resulting in injury.

Antibodies in anti-HBe-positive patient sera bind to an HBe protein expressed on the cell surface of human hepatoma cells: implications for virus clearance

The relevance of the recently described membrane-bound form of the HBe protein for the antiviral immune response was examined. The data show that antibodies in anti-HBe, but not in anti-HBc-positive human sera efficiently bind to the membrane expressed HBe. No evidence was obtained that the HBc can reach the cell surface in a form that can be detected with human antibodies. The findings suggest that the decline of virus titer that is usually observed after seroconversion from HBe to anti-HBe might be the result of an antibody-mediated elimination of infected cells.

Hepatitis B virus propagated in a rat hepatoma cell line is infectious in a primate model

The human hepatitis B virus (HBV) produced by a rat hepatoma cell line through transfection with HBV DNA is infectious in the human primate model--chimpanzee. Since hepadnaviruses are known to have an extremely narrow host range, our results support the idea that the host species barrier of HBV infection resides on the penetration/adsorption step rather than any postpenetration intracellular event during the virus life cycle.

Changing of hepatitis B virus markers in patients with bone marrow transplantation

The hepatitis B virus (HBV) infection and its resulting hepatic abnormalities are very high in prevalence among the Taiwan population. They also seem to compose a major problem to patients subjected to bone marrow transplantation (BMT) due to intensive chemoradiotherapy. In this study, the sera of 42 patients were investigated before and after BMT to detect the presence of HBV markers and to test their liver function (LF). Being followed-up for 3-12 months after BMT, 12 out of 27 were found to have altered HBV markers according to the classification of the following: seroconversion of HBsAg, clearance of HBsAb, appearance of HBeAg, clearance of HBeAb, and acute hepatitis. Thirty-seven out of 42 patients (88.1%) were found in routine LF test to develop one or more abnormality; however, 90% of them turned normal within one year after BMT. Only one patient died of complications associated with fulminant hepatitis. In conclusion, the previous hepatic damage from HBV infection appears unlikely to increase the risk of posttransplant morbidity and mortality.

Persistence of antibodies after immunization with a recombinant yeast-derived hepatitis B vaccine following two different schedules

Four years after vaccination of healthy adults with either a recombinant yeast-derived (YDV) or plasma-derived (PDV) hepatitis B vaccine, the persistence of antibodies to hepatitis B surface antigen (anti-HBs) was examined. Subjects received three 20 micrograms doses in the deltoid region according to either a 0, 1, 6 month or 0, 1, 2 month vaccination schedule, with a 20 micrograms booster dose of YDV administered at month 12 for subjects on the second schedule. The recombinant vaccine was found to be immunologically comparable to the PDV, with anti-HBs persisting equally in both groups.