抗肝炎转基因枸杞新品种培育的初步研究

以质粒pMVL-HisE制备金粉子弹,通过基因枪轰击枸杞叶片,经壮观霉素筛选获得了抗性完整再生植株,为探索提高转基因植株同质化程度的可能途径,对再生植株在高浓度的壮观霉素选择压下进行了2轮次的再生抗性筛选,并通过腋芽繁殖的方式继代4～6次,并进一步对枸杞叶绿体转化植株进行PCR扩增分子检测,结果初步证明外源抗肝炎病毒基因已经导入转基因枸杞植株体内。

抗肝炎转基因枸杞新品种培育的初步研究

以质粒pMVL-HisE制备金粉子弹,通过基因枪轰击枸杞叶片,经壮观霉素筛选获得了抗性完整的再生植株;为探索提高转基因植株同质化程度的可能途径,对再生植株在高浓度的壮观霉素选择压下进行了2轮次的再生抗性筛选,并通过腋芽繁殖的方式继代4-6次,并进一步对枸杞叶绿体转化植株进行PCR扩增分子检测,结果初步证明外源抗肝炎病毒基因已经导入转基因枸杞植株体内。

Autoantibodies and hepatitis C virus genotypes in chronic hepatitis C patients in Estonia

AIM: To determine the prevalence of several autoantibodies in chronic hepatitis C patients, and to find out whether the pattern of autoantibodies was associated with hepatitis C virus (HCV) genotypes. METHODS: Sera from 90 consecutive patients with chronic hepatitis C were investigated on the presence of anti-nuclear (ANA), anti-mitochondrial (AMA), anti-smooth muscle (SMA), anti-liver-kidney microsomal type 1 (LKMA1), anti-parietal cell (PCA), anti-thyroid microsomal (TMA), and anti-reticulin (ARA) autoantibodies. The autoantibodies were identified by indirect immunofluorescence. HCV genotypes were determined by a restriction fragment length polymorphism analysis of the amplified 5' noncoding genome region. RESULTS: Forty-six (51.1%) patients were positive for at least one autoantibody. Various antibodies were presented as follows: ANA in 13 (14.4%) patients, SMA in 39 (43.3%), TMA in 2 (2.2%), and ARA in 1 (1.1%) patients. In 9 cases, sera were positive for two autoantibodies (ANA and SMA). AMA, PCA and LKMAI were not detected in the observed sera. HCV genotypes were distributed as follows: 1b in 66 (73.3%) patients, 3a in 18 (20.0%), and 2a in 6 (6.7%) patients. CONCLUSION: A high prevalence of ANA and SMA can be found in chronic hepatitis C patients. Autoantibodies are present at low titre (1:10) in most of the cases. Distribution of the autoantibodies show no differences in the sex groups and between patients infected with different HCV genotypes.

In vitro resistance to interferon of hepatitis B virus with precore mutation

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 lll 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.

Relationship between HLA-DR gene polymorphisms and outcomes of hepatitis B viral infections:A meta-analysis

AIM:To assess the rigorous relationship between human leukocyte antigens(HLA)-DR alleles and outcomes of hepatitis B virus(HBV) infections by means of metaanalysis.METHODS:Medline/PubMed,EMBASE,CNKI and VIP were searched to identify relevant studies.Study quality was evaluated using the Newcastle-Ottawa Scale.Odds ratios(OR) and 95% confidence interval(95% CI) were pooled using Stata 11.0.Subgroup analyses were performed by ethnicity.Heterogeneity and publication bias analyses were performed to validate the credibility.RESULTS:A total of 2609 patients with chronic hepatitis B and 2606 controls spontaneously recovering from prior HBV infection were included.Meta-analysis showed that HLA-DR*04(OR = 0.72,95% CI:0.60-0.85) and DR*13(OR = 0.27,95% CI:0.19-0.37) alleles were significantly associated with HBV clearance while patients carrying HLA-DR*03(OR = 1.47,95% CI:1.16-1.87) or DR*07(OR = 1.59,95% CI:1.24-2.03) alleles had a significantly increased risk of chronic HBV persistence.For the HLA-DR*01 polymorphism,a significantly association with HBV clearance was found in Chinese Han group(OR = 0.48,95% CI:0.26-0.86),but not found in other ethnic groups(P = 0.191).For other polymorphisms,no association with the HBV infection outcome was found.CONCLUSION:HLA-DR*04 and DR*13 alleles may be the protective factors for HBV clearance and HLADR*03,and DR*07 alleles may be the risk factors for HBV persistence.

Human leukocyte antigen class II DQB1*0301, DRB1*1101 alleles and spontaneous clearance of hepatitis C virus infection: A meta-analysis

AIM： To assess the associations of human leukocyte antigen （HI_A） class Ⅱ DQB1＊0301 and/or DRB1＊1101 allele with spontaneous hepatitis C virus （HCV） clearance by meta-analysis of individual dataset from all studies published till date. METHODS： To clarify the impact of HLA class Ⅱ polymorphisms on viral clearance, we performed a metaanalysis of the published data from 11 studies comparing the frequencies of DQB1＊0301 and DRB1＊1101 alleles in individuals with spontaneous resolution to those with persistent infection. As we identified the heterogeneity between studies, summary statistical data were calculated based on a random-effect model. RESULTS： Meta-analyses yielded summary estimatesodds ratio （OR） of 2.36 [95%CI （1.62, 3.43）, P〈0.00001] and 2.02 [95%CI （1.56, 2.62）, P〈0.00001] for the effects of DQB1＊0301 and DRB1＊1101 alleles on spontaneous clearance of HCV, respectively. CONCLUSION： These results support the hypothesis that specific HLA class Ⅱ alleles might influence the susceptibility or resistance to persistent HCV infection. Both DQB1＊0301 and DRB1＊1101 are protective alleles and present HCV epitopes more effectively to CD4^＋T lymphocytes than others, and subjects with these two alleles are at a lower risk of developing chronic HCV infection. Large, multi-ethnic confirmatory and welldesigned studies are needed to determine the host genetic determinants of HCV infection.

Quantification of HBsAg:Basic virology for clinical practice

Hepatitis B surface antigen (HBsAg) is produced and secreted through a complex mechanism that is still not fully understood. In clinical fields, HBsAg has long served as a qualitative diagnostic marker for hepatitis B virus infection. Notably, advances have been made in the development of quantitative HBsAg assays, which have allowed viral replication monitoring, and there is an opportunity to make maximal use of quantitative HBsAg to elucidate its role in clinical fields. Yet, it needs to be underscored that a further understanding of HBsAg, not only from clinical point of view but also from a virologic point of view, would enable us to deepen our insights, so that we could more widely expand and apply its utility. It is also important to be familiar with HBsAg variants and their clinical consequences in terms of immune escape mutants, issues resulting from overlap with corresponding mutation in the P gene, and detection problems for the HBsAg variants. In this article, we review current concepts and issues on the quantification of HBsAg titers with respect to their biologic nature, method principles, and clinically relevant topics.

Prevalence of hepatitis B virus precore stop codon mutations in chronically infected children

AIM： To find out whether there is a significant difference in the prevalence of the precore stop codon mutation between HBeAg positive and anti-HBe positive children. METHODS： We investigated a large pediatric population of 155 European children （mean age 10.9 years） with chronic hepatitis B by PCR and direct sequencing. Ninety were HBeAg positive and 65 had seroconversion to anti-HBe. Additionally genotyping was performed. RESULTS： Seventy-four （48%） of the sequenced HBV strains were attributed to genotype D and 81 （52%） to genotype A. In the group of 90 HBeAg positive patients, 2 （2.2%） 1896-G-to-A transitions leading to precore stop codon mutation were found, and in the group of 65 anti-HBe positive children, 5 （7.7%） were identified harbouring HBeAg-minus mutants. The difference was not statistically significant （P= 0.13）. CONCLUSIONS： HBeAg minus variants as predominant viral HB strains play a minor role in the course of chronic hepatitis B in European children.

Relationship of human leukocyte antigen class II genes with the susceptibility to hepatitis B virus infection and the response to interferon in HBV-infected patients

AIM： To study the relationship of human leukocyte antigen （HLA）-DRB1 and -DQB1 alleles with the genetic susceptibility to HBV infection and the response to interferon （IFN） in HBV-infected patients. METHODS： Low-resolution DNA typing kit was used to determine HLA-DR-1 and -DQB1 genes in 72 patients with chronic hepatitis B （CHB） and HLA-DRB1 in 200 healthy people ready to donate their bone marrow in Shanghai. Among CHB patients, 35 were treated with IFNα-1b for 24 wk. RESULTS： The frequencies of HLA-DRBI＊06, DRBI＊08 and DRB1＊16 alleles in 72 patients were higher than in 200 healthy people （2.08% vs0%, OR = 3.837, P= 0.018; 11.11% vs5.50%, OR = 2.148, P= 0.034; and 6.94% vs 3.00%, OR = 0.625, P = 0.049, respectively）; whereas that of DRBI＊07 allele was lower （2.78% vs 7.75%, OR = 0.340, P= 0.046）. The frequency of HLA-DRBI＊ 14 allele was higher in 11 responders to IFN compared with 24 non-responders （18.18% vs2.08%, OR = 10.444, P = 0.031）, whereas that of DQBI＊07 allele was inverse （9.09% vs37.50%, OR = 0.167, P= 0.021）. CONCLUSION： The polymorphism of HLA class II may influence the susceptibility to HBV infection and the response to IFN in studied CHB patients. Compared with other HLA-DRB1 alleles, HLA-DRBI＊06, DRBI＊08, and DRB1＊16 may be associated with chronicity of HBV infection, HLA-DRBI＊07 with protection against HBV infection, and HLA-DRB1＊14 allele may be associated with a high rate of the response of CHB patients to IFN treatment. Compared with other HLA-DQB1 alleles, HLA-DQBI＊07 may be associated with low response rate to IFN. 2005 The WJG Press and Elsevier Inc. All rights reserved

Genetic diversity of the hepatitis C virus: Impact and issues inthe antiviral therapy

The hepatitis C Virus (HCV) presents a high degree of genetic variability which is explained by the combination of a lack of proof reading by the RNA dependant RNA polymerase and a high level of viral replication. The re- sulting genetic polymorphism defines a classification in clades, genotypes, subtypes, isolates and quasispecies. This diversity is known to reflect the range of responses to Interferon therapy. The genotype is one of the pre- dictive parameters currently used to define the antiviral treatment strategy and the chance of therapeutic suc- cess. Studies have also reported the potential impact of the viral genetic polymorphism in the outcome of antivi- ral therapy in patients infected by the same HCV geno- type. Both structural and non structural genomic regions of HCV have been suggested to be involved in the Inter- feron pathway and the resistance to antiviral therapy. In this review, we first detail the viral basis of HCV diversity. Then, the HCV genetic regions that may be implicated in resistance to therapy are described, with a focus on the structural region encoded by the E2 gene and the non- structural genes NS3, NS5A and NS5B. Both mechanisms of the Interferon resistance and of the new antiviral drugs are described in this review.

Significance of hepatitis B virus surface antigen, hepatitis C virus expression in hepatocellular carcinoma and pericarcinomatous tissues

AIM： To investigate the correlation between hepatitis B virus surface antigen （HBsAg）, hepatitis C virus （HCV） expression in hepatocellular carcinoma （HCC）, the HAI score of the noncancerous region of the liver and the serum Alpha fetoprotein （AFP） level. METHODS： The patterns of HBsAg and HCV in 100 cases of HCC and their surrounding liver tissues were studied on paraffin-embedded sections with immunohistochemistry, the histological status was determined by one pathologist and one surgeon simultaneously using the hepatitis activity index （HAIl score, and AFP was detected by radioimmunity. The study included 100 consecutive patients who underwent curative resection for HCC. Based on HBsAg and HCV expression, the patients were classified into 4 groups： patients positive for HBsAg （HBsAg group）, patients positive for HCV （HCV group）, patients negative for both HCV and HBsAg （NBNC group） and patients positive for both HBsAg and HCV （BC group）. RESULTS： The BC group had significantly higher HAI scores than the other three groups. （BC 〉 HCV 〉 HBsAg 〉 NBNC）. HBV and HCV virus infection was positively correlated with HAI （rs = 0.39, P = 0.00011. The positive rate of AFP （85.7%） and the value of AFP （541.2 ng/mL） in the group with HBV and HCV co-infection were the highest among the four groups. The positive rate （53.3%） of AFP and the value of AFP （ 53.3 ng/mL） in the group with none-infection of HBV and HCV were the lowest. HBV and HCV virus infection was positively correlated with AFP（rs = 0.38, P = 0.0001）. CONCLUSION： The AFP increase in patients with liver cancer was positively correlated with the infection of HBV and HCV. The-serum AFP elevation by the infection of HBV and HCV is one of mechanisms which lead to hepatocarcinogenesis, and the antivirus intervening treatment of hepatitis is significant for the prognosis of liver cancer. From our Spearman＇s rank correlation analysis, we can conclude that the severity of virally induced inflammation is correlated with HBsAg and HCV expression in HCC tissues and noncancerous tissues. Prior co-infection of HBV in HCV patients may be an adverse risk factor for intrahepatic inflammation.