Multiplication of hepatitis B virus in fulminant hepatitis B.

The presence in serum of hepatitis B e antigen (HBeAg) and hepatitis B virus DNA, which are each regarded as reflecting multiplication of hepatitis B virus, were looked for one to five days after the onset of hepatic encephalopathy in 64 patients with fulminant hepatitis B. HBeAg and hepatitis B virus DNA were found in the serum of only 24 (37%) and six (9%) patients, respectively. Hepatitis B virus DNA was absent from the serum in all 13 patients positive for anti-HBs. These findings indicate that replication of hepatitis B virus stopped after the onset of hepatic encephalopathy in most of the patients and support the view that an enhanced immune response stops the replication. Agents that inhibit viral multiplication would probably not have any effect at this stage of the disease.     

Antigenic and structural relationships of the surface antigens of hepatitis B virus, ground squirrel hepatitis virus, and woodchuck hepatitis virus.

The surface antigens of human hepatitis B (HBsAg), ground squirrel hepatitis (GSHsAg), and woodchuck hepatitis (WHsAg) viruses were compared serologically, and their major polypeptides were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and tryptic peptide mapping. Results showed that both GSHsAg and WHsAg are antigenically cross-reactive, that their major pairs of polypeptides have identical mobilities on sodium dodecyl sulfate gels, and that the major polypeptides of GSHsAg and WHsAg migrate faster in sodium dodecyl sulfate-polyacrylamide gel electrophoresis than do the corresponding bands of HBsAg. The peptide maps of the major (P-22) surface antigen polypeptides of GSHsAg and WHsAg showed that they shared over half of their spots. Peptide mapping of HBsAg subtypes indicated a close relationship between the major polypeptides (P-24) of adw and adr and a more distal relationship to ayw. Only about 25% of the spots shared by the combined HBsAg subtypes were also found in the peptide maps of GSHsAg and WHsAg, indicating at least some structural homology among the major polypeptides of the human and animal virus surface antigen particles. This is also reflected in the serological cross-reactivity among HBsAg, GSHsAg, and WHsAg. Further, the detection of ground squirrel and woodchuck antigens by Ausria II radioimmunoassay, combined with peptide mapping data indicating the common origin of these viruses, suggests that the common a determinant is shared by each and is restricted to approximately 25% of the sequences in their major polypeptides.     

Serological relationship of woodchuck hepatitis virus to human hepatitis B virus.

Two antigenic systems of the woodchuck hepatitis virus have been identified. The relationship between viral antigens of the woodchuck hepatitis virus and the human hepatitis B virus was determined by using immunoprecipitation, hemagglutination, and immune electron microscopy techniques. Antigens found on the cores of the two viruses were cross-reactive. Lack of cross-reactivity between the surface antigens of the two viruses in immunodiffusion experiments suggested that the major antigenic determinants of the viral surfaces are different; however, results of passive hemagglutination tests indicated that there are common minor determinants. Nucleic acid homology, as measured by liquid hybridization, was found to be 3 to 5% of the viral genomes. The results of this study provide further evidence that woodchuck hepatitis virus is the second member of a new class of viruses represented by human hepatitis B virus. Since virus-infected woodchucks may acquire chronic hepatitis and hepatocellular carcinoma, these antigens and their respective antibodies will be useful markers for following the course of virus infection in investigations of the oncogenic potential of this class of viruses. The nucleocapsid antigen described may be a class-specific antigen of these viruses and, thus, may be useful in discovering new members of the group.     

Core particles of hepatitis B virus and ground squirrel hepatitis virus. II. Characterization of the protein kinase reaction associated with ground squirrel hepatitis virus and hepatitis B virus.

The recently described protein kinase activity in hepatitis B virus core antigen particles (Albin and Robinson, J. Virol. 34:297-302, 1980) has been demonstrated here in the liver-derived core particles of ground squirrel hepatitis virus. Both protein kinase activities were initially associated with DNA polymerase-positive heavy core particles in CsCl density equilibrium gradients and shifted to polymerase-negative cores during the course of purification. The major core-associated polypeptide of each virus was the dominant species labeled. A variable number of other polypeptide species were also labeled by this reaction. Tryptic peptide mapping of both major and minor phosphorylated polypeptides of each virus resulted in similar patterns, suggesting that many of the sites of phosphorylation were the same in the components of each core particle. Hydrolysis of these phosphorylated core particles revealed a major phosphoamino acid as serine and a minor phosphoamino acid as threonine. The products of the protein kinase reaction in both human hepatitis B and ground squirrel hepatitis virus core particles, then, share many characteristics. The possible function(s) of this protein kinase activity is discussed in the light of similarly characterized activities in other animal viruses.     

Hybrid hepatitis B virus nucleocapsid bearing an immunodominant region from hepatitis B virus surface antigen.

A hepatitis B core antigen (HBcAg) gene bearing the 39-amino-acid-long domain A of hepatitis B surface antigen (HBsAg) within the HBcAg immunodominant loop has been constructed and expressed in Escherichia coli. Chimeric capsids demonstrated HBs but not HBc antigenicity and elicited in mice B-cell and T-cell responses against native HBcAg and HBsAg.     

Perinatal transmission of hepatitis B virus.

Transmission of hepatitis B virus from carrier mothers to their infants seems most likely to occur during birth. Both cord blood and breast milk have been found to be positive (in 35% and 72% of cases respectively) for hepatitis B surface antigen (HBsAg), but they do not appear to play an important role in transmission. To control this problem high-risk women should be tested during pregnancy for HBsAg. The infants of infected women should be given several doses of hepatitis B immunoglobulin starting at birth. In less developed regions, where hepatitis B is endemic, administration of the immunoglobulin in combination with vaccine, or even the vaccine alone, may be preferable in order to provide infants with lasting protection.     

Fidelity of hepatitis B virus polymerase.

Although efficient vaccines are available, chronic hepatitis B (HBV) infection poses a major health problem worldwide, and prolonged treatment of chronically infected HBV patients with nucleoside analogs often results in drug-resistant HBV variants. Therefore, it is critical to evaluate the contribution of the HBV polymerase to mutations. FLAG-tagged wild-type (FPolE) and mutant (FPolE/D551A) HBV polymerases have been expressed in insect cells and purified. The purified FPolE showed DNA polymerase activity, but FPolE/D551A did not, implying that the activity was derived from FPolE. No 3'-->5'exonuclease activity was detected in FPolE. The fidelity of FPolE was investigated and compared with that of HIV-1 RT, which is highly error-prone. The fidelity of HBV polymerase seems to be achieved by increasing the Km for the dNTP being misinserted. The nucleotide misinsertion efficiency of FPolE and HIV-1 RT ranged from 3.59 x 10-4 (C : T) to 1.51 x 10-3 (G : T) and from 1.75 x 10-4 (C : T) to 1.62 x 10-3 (G : T), respectively, and the overall misinsertion efficiency of HIV-1 RT was just 1.04-fold higher than that of FPolE, implying that HBV polymerase is fairly error-prone. Though HBV genetic mutation rate in replication is thought to be between those in RNA and DNA viruses, our data shows that the rate of mutation by HBV polymerase is higher than the rate of genetic mutation in vivo. This may be a result from more overlapping HBV genes in the HBV genome than that of other retroviruses.     

Structure of the hepatitis B virus genome.

The extent and position of the single-stranded gap in DNA molecules from Dane particles isolated from two donors of the adw serotype were determined by molecular hybridization and electron microscopic methods. The results showed that in each preparation more than 99% of the circular molecules are of uniform length and contain both single- and double-stranded regions. They confirmed that one end of the short strand is fixed with respect to the single EcoRI site within the molecule and to the nick in the long strand, but they also showed that although the position of the other end is variable, there is a preferred minimum length of about 650 to 700 nucleotides for the single-stranded region.     

Defective replication units of hepatitis B virus.

Templates for the synthesis of defective hepatitis B virus RNA pregenomes were constructed. Viral sequences in these constructs were replaced by the neomycin resistance gene. Deletions spanned up to 80% of the genome and did not include the cohesive end region. The size of the defective replication units was reduced up to half of the wild-type unit length. After cotransfection with replication competent wild-type DNA, defective pregenomes became included into the pool of replicating viral nucleic acids. A natural template for a defective pregenome was derived from the integrated state in a hepatocellular carcinoma. Owing to a deletion, this unit was devoid of the hepatitis B virus enhancer.     

Immunology of hepatitis B virus and hepatitis C virus infection

More than 500 million people worldwide are persistently infected with the hepatitis B virus (HBV) and/or hepatitis C virus (HCV) and are at risk of developing chronic liver disease, cirrhosis and hepatocellular carcinoma. Despite many common features in the pathogenesis of HBV- and HCV-related liver disease, these viruses markedly differ in their virological properties and in their immune escape and survival strategies. This review assesses recent advances in our understanding of viral hepatitis, contrasts mechanisms of virus-host interaction in acute hepatitis B and hepatitis C, and outlines areas for future studies.     

Prevalence of hepatitis B virus in chronic hepatitis B patients

The aim of the current study was to detect HBV by Real time - PCR in chronic hepatitis B patients. Fifty-eight sera of chronic hepatitis B patients were subjected during the period March 2009 to April 2010 in Ilam cities in West of Iran. Sera assayed by real-time PCR and ELISA methods. Twenty serum samples from healthy volunteers and non-hepatitis B patients and negative for hepatitis B seromarkers served as negative controls for the study. Among fifty-eight sera, ELISA showed fifty-five (94.8%) of the samples were positive for HBsAg and three (5.2%) negative results obtained while real-time PCR specified fifty-eight (100%) positive results in chronic hepatitis B patients. HBsAg status did not necessarily reflect HBV DNA level in the serum, as 5.2% of chronic Hepatitis B patients were positive for HBV DNA but negative for HBsAg. HBV DNA was not found to be positive amongst any of the negative controls. Real time - PCR is a sensitive and reproducible assay for HBV DNA quantization.     

Lymphocyte and neutrophil dysfunction associated with hepatitis B virus and hepatitis non-A, non-B virus infection in the chimpanzee.

Chimpanzees were examined for the effect of viral hepatitis infections on specific and nonspecific immune response mechanisms. The data suggest that infection with either hepatitis B virus or hepatitis non-A, non-B virus may result in suppression of cellular immune response components. Mitogen-induced lymphocyte proliferation was lower in virus-infected chimpanzees than in naive animals. Neutrophils from virus infected animals exhibited decreased or altered chemiluminescence kinetics.     

A plant-derived edible vaccine against hepatitis B virus.

The infectious hepatitis B virus represents 42 nm spherical double-shelled particles. However, analysis of blood from hepatitis B virus carriers revealed the presence of smaller 22 nm particles consisting of a viral envelope surface protein. These particles are highly immunogenic and have been used in the design of hepatitis B virus vaccine produced in yeast. Upon expression in yeast, these proteins form virus-like particles that are used for parenteral immunization. Therefore, the DNA fragment encoding hepatitis B virus surface antigen was introduced into Agrobacterium tumerifacience LBA4404 and used to obtain transgenic lupin (Lupinus luteus L.) and lettuce (Lactuca sativa L.) cv. Burpee Bibb expressing envelope surface protein. Mice that were fed the transgenic lupin tissue developed significant levels of hepatitis B virus-specific antibodies. Human volunteers, fed with transgenic lettuce plants expressing hepatitis B virus surface antigen, developed specific serum-IgG response to plant produced protein.     

Sexual transmission of hepatitis C virus and its relation with hepatitis B virus and HIV.

OBJECTIVE--To determine the extent of transmission of hepatitis C virus in sexual partners of intravenous drug misusers and to examine the relation between the prevalences of HIV, hepatitis B virus, and hepatitis C virus infections in homosexual men and intravenous drug misusers and their sexual partners. DESIGN--Serum samples collected between 1984 and 1988 were tested for hepatitis B virus markers and antibodies against hepatitis C virus by enzyme linked immunosorbent assay (ELISA) and for HIV antibody by enzyme immune analysis and western blotting. SETTING--Large referral university hospital with an external AIDS clinic in the metropolitan area of Barcelona, Spain. SUBJECTS--243 Intravenous drug misusers, 143 of their regular heterosexual partners, and 105 homosexual men. MAIN OUTCOME MEASURES--Prevalences of hepatitis C virus, hepatitis B virus, and HIV infections. RESULTS--In all, 178 of the 243 (73%) intravenous drug misusers, 16 out of 143 (11%) of their partners, and 17 of the 105 (16%) homosexual men had antibodies against hepatitis C virus. The presence of hepatitis C virus infection was unrelated to sex, age, the presence of HIV or hepatitis B virus infections, or the Centers for Disease Control stage of HIV. In sexual partners of intravenous drug misusers there were strong correlations between the presence of hepatitis C virus infection and that of HIV (p = 0.001) and hepatitis B virus (p = 0.013) infections. CONCLUSIONS--Intravenous drug misusers have a high risk of acquiring hepatitis C virus, hepatitis B virus, and HIV infections, but the presence of hepatitis C virus infection seems to be unrelated to the presence of the other two viruses. Homosexual men have a high prevalence of HIV and hepatitis B virus infections with a low prevalence of hepatitis C virus infection, the presence of which is not related to that of the other two infections. Conversely, heterosexual partners of intravenous drug misusers have low prevalences of the three virus infections, but the presence of hepatitis C virus infection correlates significantly with the presence of HIV and hepatitis B infections. The rate of sexual transmission of hepatitis C virus seems to be low, even in partners of people known to be seropositive for this virus.     

High-level hepatitis B virus replication in transgenic mice.

Hepatitis B virus (HBV) transgenic mice whose hepatocytes replicate the virus at levels comparable to that in the infected livers of patients with chronic hepatitis have been produced, without any evidence of cytopathology. High-level viral gene expression was obtained in the liver and kidney tissues in three independent lineages. These animals were produced with a terminally redundant viral DNA construct (HBV 1.3) that starts just upstream of HBV enhancer I, extends completely around the circular viral genome, and ends just downstream of the unique polyadenylation site in HBV. In these animals, the viral mRNA is more abundant in centrilobular hepatocytes than elsewhere in the hepatic lobule. High-level viral DNA replication occurs inside viral nucleocapsid particles that preferentially form in the cytoplasm of these centrilobular hepatocytes, suggesting that an expression threshold must be reached for nucleocapsid assembly and viral replication to occur. Despite the restricted distribution of the viral replication machinery in centrilobular cytoplasmic nucleocapsids, nucleocapsid particles are detectable in the vast majority of hepatocyte nuclei throughout the hepatic lobule. The intranuclear nucleocapsid particles are empty, however, suggesting that viral nucleocapsid particle assembly occurs independently in the nucleus and the cytoplasm of the hepatocyte and implying that cytoplasmic nucleocapsid particles do not transport the viral genome across the nuclear membrane into the nucleus during the viral life cycle. This model creates the opportunity to examine the influence of viral and host factors on HBV pathogenesis and replication and to assess the antiviral potential of pharmacological agents and physiological processes, including the immune response.     

Functional organization of the hepatitis B virus enhancer.

We have studied the functional constituents of the hepatitis B virus enhancer in a number of cell lines. The sequence of this enhancer, being embedded within an open reading frame of the virus, is in part evolutionarily frozen and therefore serves as a good model to investigate the fundamental enhancer elements. The hepatitis B virus enhancer contains three functionally important DNA sequence elements, EP, E, and NF-1a, each of which is bound by a distinct protein(s). The synergistic action of these elements accounts for all of the enhancer activity in a nonliver cell line and for most, but not all, of the activity in liver-derived cell lines. Multimers of the E but not of the EP element act as an autonomous enhancer. Conversely, a single element of either the E or the NF-1a element can act only when linked to the EP element. These results suggest that EP is a crucial enhancer element that acts only in interaction with a second enhancer element with intrinsic enhancer activity. Interestingly, a highly similar enhancer structure is found in a number of distinct viruses.     

Effect of concurrent acute infection with hepatitis C virus on acute hepatitis B virus infection.

OBJECTIVE--To investigate the possible interference with acute hepatitis B virus infection by co-infection with hepatitis C virus. DESIGN--Analysis of stored sera collected for transfusion transmitted viruses study in 1970s. SETTING--Four major medical centres in the United States. PATIENTS--12 recipients of blood infected with hepatitis B virus. MAIN OUTCOME MEASURES--In 1970s, presence of antibodies in hepatitis B virus and raised serum alanine aminotransferase concentration; detection of antibodies to hepatitis C virus with new enzyme linked immunoassays. RESULTS--Five of the 12 patients were coinfected with hepatitis C virus. Hepatitis B surface antigen was first detected at day 59 in patients infected with hepatitis B virus alone and at day 97 in those coinfected with hepatitis C virus (p = 0.01); median durations of antigenaemia were 83 and 21 days respectively (p = 0.05), and the antigen concentration was lower in the coinfected patients. Alanine aminotransferase patterns were uniphasic when hepatitis B virus infection occurred alone (range 479-2465 IU/l) and biphasic in patients with combined acute infection (no value > 380 IU/l; p = 0.0025). Four coinfected recipients developed chronic hepatitis C virus infection. The fifth patient was followed for only four months. CONCLUSIONS--Acute coinfection with hepatitis C virus and hepatitis B virus inhibits hepatitis B virus infection in humans, and onset of hepatitis B may reduce the severity of hepatitis C virus infection but not frequency of chronicity. Alanine aminotransferase concentration showed a biphasic pattern in dual infection.