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Cui XJ, Cho YK, Song BC. Influence of the basal core promoter and precore mutation on replication of hepatitis B virus and antiviral susceptibility of different genotypes. J Med Virol 2015; 87:601-8. [PMID: 25612255 DOI: 10.1002/jmv.24117] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2014] [Indexed: 12/22/2022]
Abstract
Mutations in the basal core promoter (BCP) and precore (PC) regions of the hepatitis B virus (HBV) are more common in genotypes B and C than in genotype A, suggesting that these mutations might affect replication competency depending on genotype. The purpose of the study was to investigate the influence of these mutations on the capacity of HBV for replication and antiviral drug susceptibility according to genotype. Genotypes A, B, and C of HBV strains with a BCP mutation, PC mutation, or BCP + PC mutation were made by site-directed mutagenesis. Replication competency of each construct and susceptibility to nucleos(t) ide analogues were tested in an Huh7 cell line. In genotype A, the BCP and BCP + PC mutations increased the viral replication around 6.5 times compared with the wild type, and the PC mutation alone similarly increased the viral replication around three times. In genotypes B and C, all three mutant types increased viral replication to a similar extent, regardless of mutation pattern. Interestingly, the BCP mutation appeared to have a greater effect on viral replication in genotype A than in genotypes B and C. This finding was unexpected because the BCP mutation is more common in HBV genotypes B and C. Moreover, the BCP, PC, and BCP + PC mutations decreased the sensitivity of HBV to antiviral agents to various degrees (2- to 10-fold) regardless of genotype. In conclusion, BCP and PC mutations increased viral replication regardless of HBV genotype and decreased in vitro antiviral susceptibility to the nucleos(t) ide analogues.
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Affiliation(s)
- Xiu-Ji Cui
- Department of Internal Medicine, School of Medicine, Jeju National University, Korea
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Chook JB, Ngeow YF, Yap SF, Tan TC, Mohamed R. Combined use of wild-type HBV precore and high serum iron marker as a potential tool for the prediction of cirrhosis in chronic Hepatitis B infection. J Med Virol 2011; 83:594-601. [PMID: 21328372 DOI: 10.1002/jmv.22016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Abstract
Hepatitis B virus (HBV) infection is a global health issue. Effective and individualized treatment of chronic hepatitis B to prevent progression to end-stage liver diseases and hepatocellular carcinoma is needed. HBV can be classified into eight genotypes (A-H) on the basis of genome sequence divergence. In addition, several naturally occurring HBV mutants have also been identified. The epidemiology of HBV genotypes and their implications for response to antiviral therapy have become increasingly recognized. Recent studies suggested that responses to standard interferon treatment in patients with genotype A or B are better than those with genotype C or D; however, conflicting results exist regarding the response to pegylated interferon. The influence of dose and duration on interferon-based therapy remains to be clarified. In addition to genotype, naturally occurring mutations such as precore and core promoter mutations have also attracted much attention, because they have been shown to affect the disease progression of HBV-related chronic liver disease and possibly the response to antiviral therapy. Here, we review the differences in antiviral theraputic response among HBV genotypes and discuss the role of precore or core promoter mutations in response to antiviral therapy.
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Affiliation(s)
- Chun-Jen Liu
- Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine and National Taiwan University Hospital, Taipei, Taiwan
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4
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Inhibition on Hepatitis B virus in vitro of recombinant MAP30 from bitter melon. Mol Biol Rep 2007; 36:381-8. [DOI: 10.1007/s11033-007-9191-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2007] [Accepted: 11/26/2007] [Indexed: 12/12/2022]
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Abstract
Under most circumstances, HBV is not cytopathic and it is the immune response of the host that determines the outcome of infection. The most complete immune response is associated with the most severe liver injury and the greatest likelihood of viral clearance, whereas an immature immune response leads to chronic hepatitis. The natural history of chronic hepatitis B is similar to that of acute HBV infection except for the different time frame, and can be viewed in four stages. The first stage is characterized by high viral loads and immune tolerance. In acute infection, this corresponds to the incubation period, but with neonatal chronic infection, this period often lasts for decades. In the second stage, an immunologic response develops leading to hepatocyte necrosis. In patients with chronic infection, stage 2 may persist for 10-20 years and lead to cirrhosis and its complications. When the immune response decreases the number of infected cells, a third stage begins with low viral replication, referred to as the inactive carrier state. In this stage, HBeAg is no longer detectable, a marked decrease in HBV viral load is observed, and aminotransferase levels become normal. During stage 3, some patients continue to have high levels of serum HBV DNA and amino-transferases (referred to as HBeAg-negative chronic hepatitis), because of HBV variants that prevent the production of HBeAg. In the fourth stage, patients become negative for HBeAg and positive for anti-HBs, and HBV DNA is usually no longer detectable in serum, although still present in liver tissue. Immune clearance occurs at a rate of about 1% per year in chronic carriers of HBV During stage 4, some patients can reactivate their hepatitis B when given chemotherapy or immuno-suppressive treatment. Patients with active HBV replication are at increased risk for cirrhosis, hepatic decompensation and hepatocellular carcinoma compared to inactive carriers. Available evidence indicates that control of HBV replication with antiviral agents decreases the incidence of these complications.
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Affiliation(s)
- Jean-Pierre Villeneuve
- Dioision of Hepatology, Hôpital Saint-Luc, Centre Hospitalier de l'Université de Montréal, Montréal, Canada.
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Shindo M, Hamada K, Muramatsu A, Morikawa T, Okuno T. Early reduction of infected hepatocytes by activated immunity at the time of interferon withdrawal hepatitis followed by lamivudine administration resulted in higher seroconversion in hepatitis Be antigen-positive patients with chronic hepatitis B. J Gastroenterol 2006; 41:151-7. [PMID: 16568374 DOI: 10.1007/s00535-005-1734-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Accepted: 09/08/2005] [Indexed: 02/04/2023]
Abstract
BACKGROUND It has been found that the efficacy of lamivudine (LAM) therapy can be improved by preceding administration with a short course of corticosteroid that induces a flare of the disease upon its withdrawal. Because of the side effects of corticosteroid, we tested the effect of a short course of interferon (IFN) as the primer instead of prednisolone, which was followed by LAM when the hepatitis flare occurred. The incidence of LAM resistance mutations and the effect of core promoter and precore mutations on the durability of the responses were also studied. METHODS Patients treated with interferon (IFN)-LAM therapy (n=73) were compared to those treated with IFN alone (n=117). The IFN-LAM group received IFN-alpha MU/day, t.i.w. for a 3-month period. LAM (10mg/day during 1 year) was started when IFN withdrawal hepatitis occurred during 2-10 months after stopping IFN. The LAM-resistant, core promoter, and precore mutations were examined by sequencing. RESULTS (1) The IFN-LAM group developed exacerbated hepatitis following IFN withdrawal in 63 patients before starting LAM therapy. The seroconversion (SC) rate was significantly higher in the IFN-LAM group than in the IFN-alone group (61% vs 26%, P=0.0001). (2) The LAM resistance mutation rate was 31% at 1 year after initiating LAM therapy. (3) In a stepwise discriminant-function analysis, decreased level of HBeAg determined at 4 weeks after LAM administration and increased level of HBeAb before the start of LAM administration contributed significantly on seroconversion to anti-HBe (P = 0.0073 and 0.004, respectively). (4) The reappearance rate of HBeAg within 6 months after the therapy (relapse) was 33% in the IFN-LAM group and 10% in the IFN-alone group. The prevalence of core promoter and precore mutations did not change before and after the therapy, nor did these mutations correlate with the relapse after stopping IFN-LAM therapy. CONCLUSIONS (1) Our findings suggest that early reduction of infected hepatocytes expressed by HBeAg by LAM may contribute to a high SC rate of IFN-LAM therapy. (2) The emergence of LAM-resistant mutations was similar to the previously reported rate, and neither core promoter nor precore mutations correlated with relapse of seroconverters after IFN-LAM withdrawal.
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Affiliation(s)
- Michiko Shindo
- Liver Diseases Section, Akashi Municipal Hospital, 1-33 Takashoumachi, Akashi 673-8501, Japan
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Yi J, Gong WD, Wang L, Ling R, Chen JH, Yun J. VP22 fusion protein-based dominant negative mutant can inhibit hepatitis B virus replication. World J Gastroenterol 2005; 11:6429-32. [PMID: 16425411 PMCID: PMC4355781 DOI: 10.3748/wjg.v11.i41.6429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the inhibitory effect of VP22 fusion protein-based dominant negative (DN) mutant on Hepatitis Bvrus (HBV) replication.
METHODS: Full-length or truncated fragment of VP22 was fused to C terminal of HBV core protein (HBc), and subcloned into pcDNA3.1 (-) vector, yielding eukaryotic expression plasmids of DN mutant. After transfection into HepG2.2.15 cells, the expression of DN mutant was identified by immunofluorescence staining. The inhibitory effect of DN mutant on HBV replication was indexed as the supernatant HBsAg concentration determined by RIA and HBV-DNA content by fluorescent quantification-PCR (FQ-PCR). Meanwhile, metabolism of HepG2.2.15 cells was evaluated by MTT colorimetry.
RESULTS: VP22-based DN mutants and its truncated fragment were expressed in HepG2.2.15 cells, and had no toxic effect on host cells. DN mutants could inhibit HBV replication and the transduction ability of mutant-bearing protein had a stronger inhibitory effect on HBV replication. DN mutants with full length of VP22 had the strongest inhibitory effect on HBV replication, reducing the HBsAg concentration by 81.94%, and the HBV-DNA content by 72.30%. MTT assay suggested that there were no significant differences in cell metabolic activity between the groups.
CONCLUSION: VP22-based DN mutant can inhibit HBV replication effectively.
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Affiliation(s)
- Jun Yi
- Department of general Surgery, Xijing Hospital, Fourth Military Medical University, Shaanxi Province, China
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8
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Karayiannis P, Carman WF, Thomas HC. Molecular Variations in the Core Promoter, Precore and Core Regions of Hepatitis B Virus, and their Clinical Significance. VIRAL HEPATITIS 2005:242-262. [DOI: 10.1002/9780470987131.ch15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2025]
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Abstract
AIM: To investigate the inhibitive effect of hepatitis B virus (HBV)-TRL on HBV replication.
METHODS: Based on previously constructed pcDNA3.1(-)/TRL, TR, TRmut, HBV core protein (HBVc) and hEDN, interest gene sequences TRL, TR, HBVc and hEDN were inserted into adenovirus shuttle plasmid pDC316 respectively and co-transfected HEK293 cells with rescue plasmid pBHGlox(delta)E1,3Cre to acquire RAd/TRL, TR, HBVc and hEDN. And then RAds were identified, amplified and the titers in HEK293 cells were determined. RAd/TRL and TR were named as the experimental groups, and others were control ones. After HepG2.2.15 cells were infected, RAd/TRL expression was identified by indirect immunofluorescence staining. Supernatant HBV-DNA content was determined by fluorescent quantification PCR. Meanwhile, metabolism of HepG2.2.15 cells was evaluated by MTT colorimetry.
RESULTS: RAd vectors with distinct interest gene sequence were successfully constructed. Effective expression of RAd/TRL in HepG2.2.15 cells resulted in a significant decrease of supernatant HBV-DNA content compared to RAd/TR (0.63±0.14 vs 1.60±0.47, P = 0.0266, <0.05) and other control groups (0.63±0.14 vs 8.50±2.78, 8.25±2.26, 8.25±2.29, 8.50±1.51, 8.57±1.63, P<0.01). MTT assay suggested that there were no significant differences in cell metabolic activity between groups (P>0.05).
CONCLUSION: The construction and expression of RAd/TRL has been achieved and it could inhibit HBV replication successfully, which has laid the foundation for further research on anti-HBV activity in vivo.
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Affiliation(s)
- Wei-Dong Gong
- Department of Oncology, Zhujiang Hospital, Nanfang Medical University, Guangzhou 510280, Guangdong Province, China.
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Yang HZ, Zhao JA, Dai M, Li YW, Wang YZ, Guan WB, Xie HP. Traditional Chinese medicine syndromes of chronic hepatitis B with precore mutant. World J Gastroenterol 2005; 11:2004-8. [PMID: 15800995 PMCID: PMC4305726 DOI: 10.3748/wjg.v11.i13.2004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: This study aims at exploring the distribution of TCM syndromes in CHB patients with HBV pre-core mutation (1896) and the relationship between pre-core mutation and T lymphocytes subgroup, through which to provide objective data on clinical syndrome differentiation of TCM, and further to suggest the therapeutic principle and guide clinical treatment.
METHODS: One hundred and forty CHB patients were evenly divided into two study groups, HBV pre-core mutant group and HBV pre-core wild-type group. Besides, 30 healthy blood donors were selected as a healthy control group. HBV-labeled compound, T lymphocytes subgroup, and HBV-DNA pre-core mutant were tested in the study groups. T lymphocytes subgroup were also tested in the control group. All the patients were both diagnosed by syndrome differentiation of TCM and western medicine.
RESULTS: The most common syndrome in mutant group was damp-heat combined with blood stasis, and the most common syndrome in the wild-type group was damp-heat stasis in the middle-jiao. There were more cases of medium and severe hepatitis in mutant group than that in wild-type group. The content of CD4+ lymphocytes and CD4+/CD8+ ratio were decreased gradually (healthy control group>wild-type group>mutant group). In the wild-type group, severe and medium CHB patients had considerably lower level of them than mild CHB patients. However, in the mutant group, the opposite result appeared. Meanwhile, the content of HBV-DNA in mutant group was higher than that in wild-type group.
CONCLUSION: Damp, heat, toxin and blood stasis were the basic pathogens of CHB, whether pre-core mutant or not. CHB with precore mutant may lead to more severe hepatitis. The decreased content of CD4+ lymphocytes and ratio of CD4+/CD8+ may be taken as one of the indices in confirming the deficiency syndrome of CHB patients with pre-core mutation.
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Affiliation(s)
- Hong-Zhi Yang
- Department of Traditional Chinese Medicine, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510630, Guangdong Province, China.
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Wang Y, Wei L, Jiang D, Cong X, Fei R, Xiao J, Wang Y. In vitro resistance to interferon of hepatitis B virus with precore mutation. World J Gastroenterol 2005; 11:649-55. [PMID: 15655815 PMCID: PMC4250732 DOI: 10.3748/wjg.v11.i5.649] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: Chronic hepatitis B virus (HBV) infection is predominantly treated with interferon alpha (IFN-α), which results in an efficient reduction of the viral load only in 20-40% of treated patients. Mutations at HBV precore prevail in different clinical status of HBV infection. The roles of precore mutation in the progression of chronic hepatitis and interferon sensitivity are still unknown. The aim of this study was to explore if there was any relationship between HBV precore mutation and sensitivity to interferon in vitro.
METHODS: HBV replication-competent recombinant constructs with different patterns of precore mutations were developed. Then the recombinants were transiently transfected into hepatoma cell line (Huh7) by calcium phosphate transfection method. With or without IFN, viral products in culture medium were collected and quantified 3 d after transfection.
RESULTS: We obtained 4 recombinant constructs by orientation-cloning 1.2-fold-overlength HBV genome into pUC18 vector via the EcoRI and Hind III and PCR mediated site-directed mutagenesis method. All the recombinants contained mutations within precore region. Huh7 cells transfected with recombinants secreted HBsAg and HBV particles into the cell culture medium, indicating that all the recombinants were replication-competent. By comparing the amount of HBV DNA in the medium, we found that HBV DNA in medium reflecting HBV replication efficiency was different in different recombinants. Recombinants containing precore mutation had fewer HBV DNAs in culture medium than wild type. This result showed that recombinants containing precore mutation had lower replication efficiency than wild type. HBV DNA was decreased in pUC18-HBV1.2-WT recombinants after IFN was added while others with precore mutations were not, indicating that HBV harboring precore mutation was less sensitive to IFN in cell culture system.
CONCLUSION: These data indicate that HBV harboring precore mutation may be resistant to IFN in vitro.
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Affiliation(s)
- Yan Wang
- Hepatology Institute, Peking University People's Hospital, No.11 Xizhimen South Street, Beijing 100044, China
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Gong WD, Liu J, Ding J, Zhao Y, Li YH, Xue CF. Inhibition of HBV targeted ribonuclease enhanced by introduction of linker. World J Gastroenterol 2003; 9:1504-7. [PMID: 12854151 PMCID: PMC4615492 DOI: 10.3748/wjg.v9.i7.1504] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To construct human eosinophil-derived neurotoxin(hEDN) and HBV core protein (HBVc) eukaryotic fusion expression vector with a linker (Gly4Ser)3 between them to optimize the molecule folding, which will be used to inhibit HBV replication in vitro.
METHODS: Previously constructed pcDNA3.1(-)/TR was used as a template. Linker sequence was synthesized and annealed to form dslinker, and cloned into pcDNA3.1(-)/TR to produce plasmid pcDNA3.1(-)/HBc-linker. Then the hEDN fragment was PCR amplified and inserted into pcDNA3.1(-)/HBc-linker to form pcDNA3.1(-)/TNL in which the effector molecule and the target molecule were separated by a linker sequence. pcDNA3.1(-)/TNL expression was identified by indirect immunofluorescence staining. Radioimmunoassay was used to analyse anti-HBV activity of pcDNA3.1(-)/TNL. Meanwhile, metabolism of cells was evaluated by MTT colorimetry.
RESULTS: hEDN and HBVc eukaryotic fusion expression vector with a linker (Gly4Ser)3 between them was successfully constructed. pcDNA3.1(-)/TNL was expressed in HepG2.2.15 cells efficiently. A significant decrease of HBsAg concentration from pcDNA3.1(-)/TNL transfectant was observed compared to pcDNA3.1(-)/TR (P = 0.036, P < 0.05). MTT assay suggested that there were no significant differences between groups (P = 0.08, P > 0.05).
CONCLUSION: Linker introduction enhances the inhibitory effect of HBV targeted ribonuclease significantly.
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Affiliation(s)
- Wei-Dong Gong
- Department of Pathogenic Organisms, Fourth Military Medical University, Xi'an 710033, Shaanxi Province, China
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Sugauchi F, Orito E, Ichida T, Kato H, Sakugawa H, Kakumu S, Ishida T, Chutaputti A, Lai CL, Gish RG, Ueda R, Miyakawa Y, Mizokami M. Epidemiologic and virologic characteristics of hepatitis B virus genotype B having the recombination with genotype C. Gastroenterology 2003; 124:925-32. [PMID: 12671889 DOI: 10.1053/gast.2003.50140] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND & AIMS Hepatitis B virus (HBV) isolates of genotype B (HBV/B) with or without the recombination with genotype C over the precore region plus core gene have been reported. METHODS All the 41 HBV/B isolates having the recombination with genotype C (HBV/Ba) possessed the nucleotide 1838 of A in contrast to that of G in all 29 of those without the recombination (HBV/Bj). Taking advantage of this single nucleotide polymorphism, a restriction fragment length polymorphism method was developed that distinguished HBV/Ba from HBV/Bj. RESULTS HBV/Bj was detected in 90 of the 97 (93%) carriers of HBV/B from Japan, whereas HBV/Ba occurred in all 177 carriers of HBV/B from other countries (China, 20; Hong Kong, 45; Taiwan, 32; Thailand, 30; Vietnam, 30; and the United States, 20 [all of an Asian ethnicity]). In a case-control study, hepatitis B e antigen (HBeAg) and the double mutation in the core promoter (T1762/A1764) were significantly more frequent in 80 carriers each of HBV/Ba than HBV/Bj (35% vs. 18%, P < 0.05 and 33% vs. 15%, P < 0.05, respectively). Differences in the prevalence of HBeAg were more conspicuous between the carriers of HBV/Bj and HBV/Ba older than 30 years (5 of 66 or 8% vs. 16 of 62 or 26%, P < 0.01). CONCLUSIONS HBV/B having the recombination with genotype C is frequent in Asia, except in Japan, and HBeAg is more prevalent in carriers of HBV/Ba than HBV/Bj.
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Affiliation(s)
- Fuminaka Sugauchi
- Department of Internal Medicine and Molecular Science and Clinical Molecular Informative Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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14
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Affiliation(s)
- S K Sarin
- Department of Gastroenterology, G.B. Pant Hospital, New Delhi, India.
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15
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Sallam TA, Tong CYW. Two distinct types of hepatitis B virus core promoter variants in Yemeni blood donors. J Med Virol 2002; 68:328-34. [PMID: 12226818 DOI: 10.1002/jmv.10207] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Genetic variations in the basic core promoter (BCP) region of hepatitis B virus (HBV) occur during the natural history of chronic HBV infection. This study investigates the presence of basic core promoter variations in 28 asymptomatic Yemeni blood donors, correlating variations with HBeAg phenotype and viral load. The core promoter/precore and surface gene region of HBV DNA were amplified using nested PCRs and the PCR products were sequenced either directly or after cloning. HBeAg and viral load were measured when HBV DNA was detectable. Sequencing of 18 surface PCR products indicated that all were of genotype D. Two distinct types of variants were identified in the basic core promoter: substitution only (N = 14) and major deletion (N = 9). The commonest substitutions were located at nucleotide positions 1753, 1762, and 1764; 10/14 (71.4%) were associated with the precore 1896A substitution resulting in the premature stop of the precore reading frame and 6/14 (42.9%) had viral loads above 400 copies/ml. Two forms of deletion variants were found: 8 bp deletion (1763-1770) (N = 2) and a novel 12 (1746-1757) + 8 bp (1763-1770) deletion (N = 7). The deletion sequences were never associated with the precore 1896A substitution and all had viral load below 400 copies/ml with negative HBeAg phenotype. The polymorphism 1773C was found in 9/14 (64.3%) substitution sequences whereas all deletion sequences had 1773T. Two donors had mixed sequences of basic core promoter substitution and major deletions (both 8 bp and 12 + 8 bp). While the deletion variants in these two donors were similar to others found in isolation, the substitutions were of a different pattern. Further studies are required to understand the selection process behind these variants.
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Affiliation(s)
- Talal A Sallam
- Department of Microbiology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Republic of Yemen
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Hannoun C, Horal P, Krogsgaard K, Lindh M. Mutations in the X region and core promoter are rare and have little impact on response to interferon therapy for chronic hepatitis B. J Med Virol 2002; 66:171-8. [PMID: 11782925 DOI: 10.1002/jmv.2127] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Therapy for chronic hepatitis B with interferon-alpha (IFN) may result in viral clearance and hepatitis B e seroconversion in 30-40% of patients. It is still unclear whether viral genetic variability influences response rates. However, certain core promoter mutations were recently associated with a better response to IFN. In the present study, the entire X region, including the core promoter, of hepatitis B virus (HBV) from 26 HBeAg-positive patients treated with IFN for 12 weeks, was sequenced. Serum samples pre-treatment, at end-of-treatment, and at follow-up of 18 sustained and 8 nonsustained responders were analyzed. Most patients were of European origin and had moderate aminotransferase elevation (mean 2.4 x upper limit of normal) and genotype A infection. Before treatment, 16 patients had an X region identical to a consensus sequence of the corresponding genotype; in the remaining 10 patients, a median of 1.5 mutations were found. After treatment, 1-4 new mutations (mean 1.8) had emerged in 5 patients. There was no association between specific mutations, or the number of mutations, and response to IFN. The low frequency of mutations indicates that analysis of this region is of limited clinical value and that emerging mutations in this region are not major determinants of response to treatment with IFN-alpha.
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Affiliation(s)
- Charles Hannoun
- Department of Clinical Virology, Göteborg University, Göteborg, Sweden
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Abstract
The control of the global expansion and proliferation of the AIDS pandemic has been complicated by the emergence of resistant strains of HIV-1 to the many new antiviral drugs directed to the genes coding for reverse transcriptase and protease enzymes of the virus. Similarly, new drug regimens for the management of chronic hepatitis B and C infections have been complicated by the lack of sustained clinical responses recently associated with either nucleotide mutation (HBV) or specific genotype of the virus (HCV). Commercial systems for performing and interpreting genotypic analysis will facilitate the recognition of informative mutations, standardize results between laboratories, and produce informative and interpretative result formats for optimal treatment of patients. Drug-resistant strains of herpesviruses (HSV, VZV, CMV) are generally associated with prolonged treatment of these infections in immunocompromised patients. Ultimate relevance of genotypic assays for routine clinical practice will require correlation with phenotypic results and the outcomes of long-term studies associating clinical improvement with antiviral drugs with specific mutation patterns of these viruses.
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Affiliation(s)
- T F Smith
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.
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18
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Fukuda R, Mohammad R, Hamamoto S, Ishimura N, Ishihara S, Akagi S, Watanabe M, Kinoshita Y. Clinical relevance of precore and basal core promoter variants of hepatitis B virus during natural hepatitis B e antigen seroconversion may be overstated. J Pediatr Gastroenterol Nutr 2001; 33:301-6. [PMID: 11593126 DOI: 10.1097/00005176-200109000-00014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Clinical relevance of nucleotide changes in precore and basal core promoters in the hepatitis B virus genome during hepatitis B e antigen seroconversion may be overstated. The authors investigated the existence and changes in the relative proportion of variants to wild virus that occur with seroconversion. METHODS Sera from 30 school-aged long-term hepatitis B virus carriers, including 11 tested before and after seroconversion during 1 to 8 years of follow-up, were evaluated for variations in nucleotide sequences of the basal core promoter (T1762 and A1764), precore region (A1869), and carboxyl-terminus of the X region of the hepatitis B virus genome using an amplification refractory mutation detection system with mutant-specific primers. RESULTS All variants were found to already exist before seroconversion at various wild-type/mutant ratios. The positive rates of these variants were not changed with loss of hepatitis B e antigen. Although there was a relative increase in the concentration of these mutants in wild-type/mutant mixed populations, most patients with only a wild-type population maintained the same pattern after loss of hepatitis B e antigen. CONCLUSIONS Our results indicate that hepatitis B virus exists as a quasi species, and correlations of nucleotide sequences with clinical and serologic findings must be done with caution.
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Affiliation(s)
- R Fukuda
- Second Department of Internal Medicine, Shimane Medical University, Izumo-city, Shimane, Japan.
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Mallat D, Schiff E. Viral hepatitis. Curr Opin Gastroenterol 2000; 16:255-61. [PMID: 17023883 DOI: 10.1097/00001574-200005000-00008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Viral hepatitis accounts for most liver diseases seen in hepatology practice. In the past year studies have been focused on uncovering the basic mechanisms of viral-cellular interactions, the knowledge of which will contribute to more effective treatment. Hepatitis A virus outbreaks still occur, even in the most developed countries, which points to the need for more comprehensive vaccination measures. Lessons learned from the treatment of HIV with combination antiviral therapies are being applied to both chronic hepatitis B and C. Progress has been made toward better understanding of viral kinetics and the quasi-species of hepatitis C virus with new and more sensitive diagnostic methods. Several therapeutic protocols are emerging to identify and tailor the management approach in various subsets of the population. Although posttransplantation hepatitis B has been more effectively managed with lamivudine therapy, no major advances have been accomplished in the treatment of recurrent hepatitis C among transplant recipients. Major advances in the field of viral hepatitis including A to E and TT viruses during the past year are highlighted.
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Affiliation(s)
- D Mallat
- Center for Liver Diseases, University of Miami, Miami, Florida 33136, USA
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