SEARCH · PubMed Health

Results for “HBV integration”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources

PubMed2001

[Study on the replication of hepatitis B virus compared with that of duck hepatitis B virus in primary duck hepatocytes].

OBJECTIVE: By studying the replication of Hepatitis B virus (HBV) compared with that of Duck Hepatitis B virus (DHBV) in primary duck hepatocytes (PDH), we want to explore the host-specific regulating roles on the replication of HBV in hepatocytes from heterologous species. METHODS: PDH were transfected with complete HBV genome by electroporation (transfected group, 1.19 x 10(12) copies of linear HBV DNA/1 x 10(7) PDH) or infected with DHBV (infected group, 4 x 10(8) virions/1 x 10(7) PDH). 1, 3 and 5 days after transfection or infection, HBsAg, HBeAg and DHBsAg in the supernatant and lysate of PDH were measured with IMX System or ELISA. Meanwhile, replicative intermediates of HBV DNA and DHBV DNA were analyzed by Southern blotting and dot blotting. PDH electroporated only was used as control group. RESULTS: HBsAg in the lysates of transfected group were 15.24 (1 day), 14.55 (3 days) and 5.13 (5 days; P/N values, positive > or = 2.1), HBeAg all was negative (< 2.1), and both were negative in the supernatants of transfected group. DHBsAg in the supernatants of infected group were 14.6 (1 day), 31.53 (3 days) and 34.73(5 days; S/N values, positive > or = 2.1). Dot blotting revealed that both the total amount of HBV DNA in the transfected group and DHBV DNA in the infected group were strongly positive, whereas that of the control group was negative. Southern blot analysis of intracellular total DNA indicated that there are relaxed circular (RC), covalently closed circular (ccc) and single-stranded (SS) HBV DNA replicative intermediates in the transfected group, there was no integrated HBV DNA in the cellular genome, as the same as that of DHBV DNA in the infected group. Control groups were negative at all. CONCLUSION: Our results demonstrate that expression of HBV genes and production can occur in hepatocytes from nonmammalian species and strongly support the idea that HBV replication has no critical species-specificity, and yet hepatic-specific regulating factors could be essential for viral replication.

Animals↗

PubMed1984

Establishment and characterization of a new human hepatocellular carcinoma cell line.

A human hepatocellular carcinoma cell line (FOCUS--Friendship of China and United States) was derived from a patient with primary hepatocellular carcinoma. This cell line has been in continuous culture over an 18-mo period. The morphological and ultrastructural features of FOCUS are consistent with its neoplastic hepatocellular origin. FOCUS cells contain aspartate aminotransferase and glucose-6-phosphatase activity. In addition, alpha 1-antitrypsin, fibrinogen, alpha fetoprotein, and carcinoembryonic antigens were detectable in the cytoplasm of the cultured cells by immunochemical staining techniques. The karyotype of the FOCUS cell is human in origin and its contains human DNA sequences as detected by molecular hybridization analysis. The FOCUS cells do not show evidence of density-dependent inhibition of growth under confluent conditions. Repeated growth curves over an 18-mo period were identical, revealing a doubling time of 42 to 48 h. The malignant potential of FOCUS cells was further demonstrated by their ability to lead to gross tumor formation after subcutaneous injection into nude mice. From one of the solid tumors grown in nude mice, recultured cell lines have been established and found to have properties identical to the original FOCUS cell line. This FOCUS cell line represents an additional model for further investigation of tumor specific antigens and the relationship between hepatitis B virus (HBV) and hepatocellular carcinoma. Preliminary molecular characterization has indicated the existence of integrated HBV sequences within the FOCUS genome.

Animals↗

PubMed1990

Replication of hepatitis B virus in transfected nonhepatic cells.

Permanent murine fibroblasts (LTK-) were transfected with a dimer of hepatitis B virus (HBV) DNA and a neomycin resistance gene which were both linked to the simian virus 40 (SV40) early promoter/enhancer. One of the stably transfected clones, LTK4/36, which secreted HBsAg, HBeAg, and HBV DNA was further analyzed. It contained eight to nine copies of integrated HBV DNA per haploid genome and low amounts of episomal HBV DNA. The secreted viral DNA was covalently linked to protein and was associated with particles which had the characteristic density of natural virions from serum of human viremic carriers. The particles contained an endogenous DNA polymerase, small and middle surface proteins, but in contrast to natural virions very little core protein and large surface protein. Instead of core protein, they contained incompletely processed HBe protein which is colinear to core protein. The fibroblast-derived virions were less stable than virions from human carriers or from transfected hepatoma cells. After several days of storage, their DNA was only partially protected against DNase. Obviously, nonhepatic cells can express HBV-like particles, even if liver-dependent gene products like large surface protein and core protein are missing.

Animals↗

PubMed2004

Hepatitis B virus infection and vaccination among young injection and non-injection drug users: missed opportunities to prevent infection.

INTRODUCTION: We examined correlates of HBV infection and vaccination and the missed vaccination opportunities among young injection drug users (IDUs) and non-injection drug users (NIDUs). METHODS: Two hundred IDUs and 124 NIDUs aged 15-30 years were studied. Demographics, drug use and sexual behaviors, and health and incarceration history data were collected. Serology was conducted for antibodies to HBV-core antigen (anti-HBc) and HBV-surface antigen (anti-HBs). Presence of anti-HBc indicated past HBV infection; presence of anti-HBs alone indicated past vaccination. RESULTS: More IDUs had been infected with HBV in the past than NIDUs (37% versus 19%, P = 0.001). Among male and female IDUs, injection drug use behaviors were significantly associated with past infection. For female IDUs, being African-American and trading sex were also associated with previous infection. Among NIDUs, being female and longer time since sexual debut were associated with past infection. Overall, 11% were vaccinated (10% IDU versus 14% NIDU, P = 0.30). Younger age and drug treatment history were associated with vaccination. Most susceptibles (84%) experienced at least one missed opportunity for vaccination. CONCLUSION: Young drug users remain at high risk for HBV infection. Vaccination rates remain low despite multiple opportunities for vaccination. An integrated HBV immunization effort should be coordinated among venues frequented by young drug users.

Adolescent↗

PubMed2002

[Replication and transfection of hepatitis B virus DNA into primary duck hepatocytes].

OBJECTIVE: By studying the possibility of obtaining expression of human hepatitis B virus (HBV) genes and production in normal liver cells from heterologous species like normal primary duck hepatocytes (PDH), to investigate the species-specificity of HBV infection and replication. METHODS: Two days after transfecting the complete HBV genome into PDH by electroporation (transfected group), HBsAg and HBeAg in the supernatants and lysates of PDH were measured by the IMX system. Meanwhile, replication of HBV in PDH was analyzed by Southern blotting and dot blotting procedures. PDH was electroporated as control. RESULTS: HBsAg in the lysate of transfected group was 9.10 (P/N values, positive?2.1), HBeAg was 1.0 (negative?2.1), both were negative in the supernatants of transfected group. dot blotting revealed that transfected group was strongly positive, whereas the control group was negative. Southern blot analysis of intracellular total DNA indicated that there were relaxed circular (RC), covalently closed circular (CCC) and single-stranded (SS) HBV DNA replicative intermediates in the transfected group, and there was no integrated HBV DNA in the cellular genome. Control groups were negative. CONCLUSIONS: Replication of HBV can occur in hepatocytes from nonmammalian species, which strongly supports the idea that replication of HBV has no critical species-specificity, and yet it depends on the endoenvironment of hepatocyte.

Animals↗

PubMed1992

[Significance of detailed Hepatitis B virus marker studies in chronic liver diseases].

The hepatitis B virus (HBV) markers were studied by Sorin RIA kits in the sera of 390 patients suffered from histologically confirmed chronic liver disease. On the base of HBsAg, anti-HBs, anti-HBc seronegativity the HBV infection was excluded in 235 cases. In most HBV negative cases the diagnosis was fatty liver and alcoholic hepatitis (52%), while chronic active hepatitis and/or liver cirrhosis occurred only in 21.7% of patients. Past or present HBV infection was proved in 155 patients. The diagnosis of 52.9% of cases in this group was chronic active hepatitis and/or liver cirrhosis, while fatty liver and alcoholic hepatitis occurred in 27.7%. The detailed HBV marker analysis was performed in 76 patients. Previous infection without replication (anti-HBs and/or anti-HBc and/or anti-HBe positivity) was proved in 48 cases, 12 patients have active HBV infection (HBsAg, HBe, IgM anti--HBc, positivity), while in 16 cases integrated HBV infection (HBsAg, anti-HBc, anti-HBe positivity) was proved. The HBsAg--IgM complex seropositivity was detected in every case with active HBV replication. Because of therapeutic, prognostic and epidemiologic significances the detailed HBV serology in chronic liver diseases is stressed.

Adolescent↗

PubMed1987

[Hepatitis B virus integration and oncogene activation].

In hepatitis B virus (HBV) related hepatoma samples there is a high frequency of HBV-DNA integration into the chromosome, but the frequency of integration in the early-stage of carcinogenesis is expected to be even higher. Structural an analysis of integrated HBV-DNA and chromosomal flanking DNAs disclosed that the marked rearrangement of chromosomal DNA is not directly linked to carcinogenesis. HBV-DNA integration and chromosomal DNA depletion occur even in chronic hepatitis tissues. Integration is, therefore, thought to trigger a series of reactions which lead to carcinogenesis. However, the oncogene is not detected within the HBV genome, and the HBV integration site in the chromosome is variable. As one approach to clarifying the cause and effect relationship between HBV-DNA integration and liver carcinogenesis DNA transfection experiments were conducted using mouse NIH3T3 cells to detect hepatoma-related oncogenes. As a result, the well-known N-ras gene and an unknown oncogene were independently isolated from different hepatoma tissues.

Carcinoma, Hepatocellular↗

PubMed1994

[Preparation of monoclonal antibody directed against hepatitis B virus X protein and detection of reactive antigen in hepatocellular carcinoma].

A mouse monoclonal antibody directed against hepatitis B virus (HBV) X protein (HBxAg) was prepared. The antibody was used to screen by immunohistochemistry 50 liver tissue sections from patients with hepatocellular carcinoma (HCC), and 15 patients with chronic active hepatitis (CAH). 28 of 50(56%) samples were HBxAg positive in tumor tissues. The positive rates of HBxAg only in tumor tissues or in adjacent nontumor tissues were 24% and 16%. HBsAg was detected in 16% of cases in tumor tissues and 74% in surrounding nontumor tissues. In CAH samples, the positive rates of HBxAg and HBsAg were 6.6% and 73.3%. HBcAg was only detected in nontumor surrounding liver tissues, the positive rates being 18%. In CAH samples, no HBcAg was detected. The results showed that HBxAg is a common marker in liver tissue from patients with HBV-related HCC. The findings of HBxAg in the absence of detectable HBsAg and HBcAg in the liver tissues suggested that HBxAg could be independent of HBV replication and implied that the synthesis of HBxAg may be directed from integrated HBV DNA templates. It is possible to use antiHBx monoclonal antibody as a carrier for the targeting therapy of HCC.

Animals↗

PubMed1985

Presence of HBV DNA in spermatozoa: a possible vertical transmission of HBV via the germ line.

Using molecular hybridization we studied the presence and state of HBV DNA in sperm samples obtained from 17 patients with HBV infection (eight HBsAg chronic carrier, nine acute hepatitis B). Presence of HBV DNA was detected in three samples of seminal fluid from three patients with acute hepatitis. Restriction enzyme patterns of cellular DNA were consistent with presence of integrated HBV DNA sequences in spermatozoa from two of these three patients. The results indicate that HBV DNA may be present in the semen, at least during the acute phase of HBV infection. The presence of HBV DNA in seminal fluid confirms the possibility of venereal transmission. The presence of integrated sequences in spermatozoa suggests the possibility of true vertical transmission of HBV via the germ line.

DNA, Viral↗

PubMed1995

Core antigen mutations of human hepatitis B virus in hepatomas accumulate in MHC class II-restricted T cell epitopes.

Despite the extensive molecular information on serum-derived human hepatitis B viruses (HBV), liver-derived replicative HBV genomes have remained largely uninvestigated. We have examined the sequences of the entire core antigen (nucleocapsid) of liver-derived HBVs in 15 different hepatoma patients. Bona fide mutations, rather than subtype polymorphism, have been identified based on the high-frequency occurrence of structural differences from wild type at the highly evolutionarily conserved positions, instead of at the positions known to contain genetic heterogeneity among different isolates from different geographic locations. The distribution of these naturally occurring mutations of HBV core gene appears to be nonrandom and is found predominantly within three major (I, IV, and V) and four minor domains (II, III, VI, and VII). In general, domain IV mutations correlate with domain V mutations. The replicative HBV DNAs tend to accumulate a higher number of mutated core domains than the integrated HBV DNAs. At the domain level, there is no significant difference in HBV core mutation frequencies between the liver tumors and the adjacent nontumorous livers. Strikingly, domains I, III, and V coincide with three major known T cell epitopes within the core protein in acute and chronic hepatitis B patients. Furthermore, these domains coincide with HLA class II-restricted T cell epitopes, rather than with the conventional HLA class I-restricted epitopes of cytotoxic T lymphocytes. Our results support the hypothesis that HBV core antigen variants can accomplish immunoevasion via accumulated escape mutations. In addition, they also provide a potential molecular explanation for the maintenance of persistent infection of human hepatitis B virus in chronic carriers.

Adult↗

PubMed2004

[Study on the replication of Hepatitis B Virus in primary hepatocytes from heterogenous species].

OBJECTIVES: By studying the possibility and degree of the replication and expression of human hepatitis B virus (HBV) genes in normal liver cells from heterogenous species, such as primary duck hepatocytes (PDH) and primary rat hepatocytes (PRH), to investigate the species-specificity of HBV infection and replication. METHODS: PDH and PRH isolated by in situ perfusion with low concentration collagenase were transfected with complete HBV genome by electroporation (transfection group, about 1.19 10(12) copies of linear HBV DNA/1 10(7) PRH/PDH). From 1 day to 15 days after transfection, HBsAg and HBeAg in the supernatants and lysates of PRH/PDH were measured with IMX System, HBcAg was assayed with western blotting, Immunol dot blotting and Immunocytochemistry. Moreover, HBV S-mRNA and X-mRNA were tested with RT-PCR. Meanwhile, replicative intermediates of HBV DNA were analyzed by Southern blotting and Dot blotting. PRH/PDH electroporated only was used as control group. RESULTS: HBsAg in the lysates of transfected PDH group were 15.24 (1day), 14.55 (3 days) and 5.13 ( 5 days; P/N values, positive>or=2.1), HBeAg all was negative (<2.1), and both were negative in the supernatants of transfected group. Viral antigen production in transfected rat hepatocytes: HBsAg in the lysates of transfected hepatocytes was positive, P/N values ranging from 2.17 to 93.41, The average P/N values was 14.74+/-31.82, and could be maintained for 15 days after transfection. Whereas, HBsAg in the supernatants of transfected group was only found positive on 1 day after transfection, which P/N value was 6.66. HBeAg and HBcAg in the lysates of PRH of transfection group were positive during the first 3 days following transfection, P/N values was around 2.8. The total amount of HBV DNA in the transfected PDH and PRH groups was strongly positive by dot blotting, whereas that of the control group was negative. Southern blot analysis of intracellular total HBV DNA indicated that there were relaxed circular (RC), covalently closed circular (ccc) and single-stranded (SS) HBV DNA replicative intermediates in the transfected PDH and PRH groups, there was no integrated HBV DNA in the cellular genome. Control groups were negative at all. CONCLUSION: Expression of HBV genes and production can occur in hepatocytes from nonmammalian species or mammalian species, which strongly supports the idea that replication of HBV has no critical species-specificity, and yet it depends on the endoenvironment of hepatocyte.

Animals↗

PubMed1991

Hepatitis B x antigen in hepatitis B virus carrier patients with liver cancer.

Formalin-fixed, paraffin-embedded specimens from 110 cases of primary hepatocellular carcinoma were stained for hepatitis B x antigen (HBxAg), hepatitis B surface antigen (HBsAg), and hepatitis B core antigen (HBcAg). Eighty-four % of these patients were HBxAg positive in their tumor cells. Among the 110 cases studied, 80 had adjacent nontumorous tissue in the same block, and 65 of these nontumorous liver tissues stained positive for HBxAg (81%). HBsAg was positive in 19% of cases within tumor tissue and 61% in surrounding nontumorous tissue. HBcAg was positive in 11% of cases within tumor tissue and 26% in surrounding nontumorous tissue. These findings show that HBxAg is a common marker in the liver of patients with hepatitis B virus (HBV)-associated primary hepatocellular carcinoma and that it is closely associated with tumor cells in these individuals. In addition, the finding of HBxAg in the absence of detectable HBsAg and HBcAg in the liver tissues of many HBsAg carriers suggests that HBxAg could be expressed independent of HBV replication and implies that the synthesis of this antigen may be directed from integrated HBV DNA templates. The finding of HBxAg in the nucleus of hepatocytes from primary hepatocellular carcinoma patients with dysplasia, combined with the known trans-activating properties of HBxAg, implies that HBxAg plays one or more important roles in hepatocarcinogenesis. The finding of HBxAg in bile duct epithelium and cholangiocarcinoma tissues is compatible with the hypothesis that HBV may contribute to this other primary tumor type in the liver. Together, these results further implicate HBxAg in the pathogenesis of primary liver cancers.

Carcinoma, Hepatocellular↗

PubMed1990

Different forms of hepatitis B virus DNA and expression of HBV antigens in peripheral blood mononuclear cells in chronic hepatitis B.

The presence of both hepatitis B virus (HBV) DNA and HBV antigens (HBsAg, HBeAg) was assessed in peripheral blood mononuclear cells (PBMC) from 32 patients chronically infected with HBV. Three different molecular forms of HBV DNA were observed: free monomers (5), high-molecular-weight free concatemers (11), and integrated HBV DNA (9). The HBV DNA patterns in the PBMC were different from those found in liver and did not correlate with any specific profile of serum HBV markers. When the same PBMC were assayed for HBsAg, 22 of the 25 HBV DNA positive samples, but only three of the seven HBV DNA negative samples, were positive. By contrast, none of the PBMC samples from five healthy HBV vaccine recipients gave any positive signal in the HBV DNA or HBsAg assays. In some patients, T and B cells, monocytes, and polymorphonuclear (PMN) cells were assayed separately, showing that the DNA pattern was similar for these different leucocytes subsets and ruling out the possibility that these patterns might reflect PMN cell contamination. Thus, in chronic HBV infection, 87.5% (28/32) of patients were found to contain at least one HBV marker in their PBMC, and a strong correlation was found between the presence of HBV DNA and viral antigens, suggesting a specific expression of HBV encoded proteins.

B-Lymphocytes↗

PubMedDate not supplied

Hepatitis B virus DNA integration in a sequence homologous to v-erb-A and steroid receptor genes in a hepatocellular carcinoma.

Hepatitis B virus (HBV) is clearly involved in the aetiology of human hepatocellular carcinoma (HCC) and the finding of HBV DNA integration into human liver DNA in almost all HCCs studied suggested that these integrated viral sequences may be involved in liver oncogenesis. Several HBV integrations in different HCCs and HCC-derived cell lines have been analysed after molecular cloning without revealing any obvious role for HBV. From a comparison of a HBV integration site present in a particular HCC with the corresponding unoccupied site in the non-tumorous tissue of the same liver, we now report that HBV integration places the viral sequence next to a liver cell sequence which bears a striking resemblance to both an oncogene (v-erb-A) and the supposed DNA-binding domain of the human glucocorticoid receptor and human oestrogen receptor genes. We suggest that this gene, usually silent or transcribed at a very low level in normal hepatocytes, becomes inappropriately expressed as a consequence of HBV integration, thus contributing to the cell transformation.

Amino Acid Sequence↗

PubMed1991

Hepatitis B virus integration event in human chromosome 17p near the p53 gene identifies the region of the chromosome commonly deleted in virus-positive hepatocellular carcinomas.

The development of hepatocellular carcinoma (HCC) presumably occurs in multiple steps and is influenced by numerous factors. Hepatitis B virus (HBV) is strongly associated with the development of HCC in people chronically infected with the virus, but the mechanism of viral involvement remains unclear. One possibility is that the gross chromosomal alterations frequently observed in HCC DNA at the site of HBV integration may alter the expression of important nearby cellular genes. We previously reported the cloning and characterization of a HBV insert from a Chinese HCC. The viral insert mapped to chromosome 17p11.2-12, and cellular sequences were duplicated at the site of viral integration. In the present study a DNA probe derived from cellular DNA sequences adjacent to the previously characterized HBV insert was used to analyze a set of 19 matched normal liver and HBV-positive hepatoma samples obtained from the same region of China, near Shanghai. Tumor-specific DNA changes were detected in two additional HCCs, suggesting that the small region of chromosome 17p defined by the flanking cell DNA probe is commonly altered in hepatomas. Restriction fragment length polymorphism studies demonstrated that the loss of one copy of portions of chromosome 17 occurred in 10 (53%) of the 19 patients. The loss of one allele of the p53 gene (located on chromosome 17p13) occurred in at least 6 (60%) of the 10 patients who were heterozygous at the p53 locus. As the p53 gene is known to possess tumor suppressor activity, the functional loss of this gene may be a significant step in the development of a subset of HCCs. High levels of allele loss also were detected for chromosomes 8q (4 of 9; 44%) and 16p (5 of 6; 83%) and may indicate the presence of additional cellular genes whose functional loss is important in the development of HCCs.

Carcinoma, Hepatocellular↗

PubMedDate not supplied

The hepatitis B virus.

DNA recombinant technology has radically changed hepatitis B virus (HBV) virology. The genetic organization, transcription and replication of the virus are basically understood, structures of integrated HBV sequences in hepatocellular carcinoma have been characterized, and new vaccines produced by recombinant DNA technique are being developed.

Amino Acid Sequence↗

PubMedDate not supplied

Natural history of chronic hepatitis B virus infection: new light on an old story.

Chronic hepatitis B virus (HBV) infection is one of the most common persistent virus infection in man. It causes significant morbidity and mortality, and therefore is important. Extensive studies on clinicopathologic studies and long-term follow up on hepatitis B surface antigen (HBsAg) carriers have largely disclosed the natural history of chronic HBV infection. The infection easily becomes chronic when contracted in early infancy. As high as 90% of babies born to HBV carrier mothers will also become HBsAg carriers. Once chronic infection is established, it is refractory, and HBsAg carriage usually persists for life. However, the chronic infection is not monotonous, it actually evolves from an HBV replicative phase to a non-replicative phase. The host responds differently and with more complexity in different phases. The virus-host interactions, divided into three phases, virus tolerance, virus clearance and residual HBV integrated phases, result in a heterogeneous variety of hepatic lesions. The first two phases occur when HBV is actively replicating, and the last corresponds to the non-replicative phase. The high HBV level (and hence HBV gene products) renders the host's immune system tolerant to the virus, and the infected host does not exert an effort to get rid of the virus. At this stage, the liver is nearly normal, and the host is asymptomatic. However, later in the replicative phase, the HBV replication begins to wane, and the immune tolerance is no longer maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic Disease↗

PubMed1996

Inhibition of the expression of hepatitis A and B viruses (HAV and HBV) proteins by interferon in a human hepatocarcinoma cell line (PLC/PRF/5).

AIMS/METHODS: PLC/PRF/5 is a continuous human hepatocarcinoma cell line whose genome contains integrated HBV DNA and which secretes two of the hepatitis B virus envelope proteins (HBs and PreS2). This line is also susceptible to infection by hepatitis A virus and was therefore used to compare the effects of interferon on protein synthesis of these two viruses and to assess the interactions which occur between them during infection. RESULTS: Results showed that recombinant interferon alpha 2-a inhibited the expression of the two hepatitis B virus envelope antigens (HBs and PreS2) and of the only hepatitis A virus antigen in a dose-dependent fashion. Comparison of the effect of interferon on antigenic protein production of these two viruses, showed stronger inhibition of hepatitis A virus capsid antigen than of hepatitis B virus envelope antigens. Infection with hepatitis A virus also downregulates the expression of the two hepatitis B virus proteins. CONCLUSIONS: Considering the absence of cytotoxic effects from the doses used, this study confirms the relevance of this cellular model for the study of antiviral cytokines in vitro. It also provides a further rationale for the clinical evaluation of the therapeutic potential of interferons in severe hepatitis cases due either to hepatitis A virus alone or to superinfection of hepatitis B virus carriers by hepatitis A virus.

Antigens, Viral↗