中国人丙型肝炎病毒全长NS3基因的克隆、序列分析及表达

目的　为改进HCV试剂的质量克隆 1b型丙型肝炎病毒 (HCV)全长NS3基因并在原核细胞中表达。方法　用RT PCR方法从中国人血清中扩增全长NS3片段 ,进行序列分析 ,并克隆到pET3 0a(+)原核表达载体中 ,构建的原核表达载体pET NS3 180 0在大肠杆菌BL2 1(DE3 )中表达 ,用Westernblot方法进行验证。结果　扩增到 1b型HCV全长NS3片段 ,经Westernblot实验表明该片段具有抗原活性。结论　构建的质粒可在大肠杆菌中表达完整的NS3蛋白     

丙型肝炎负链RNA的检测及意义

检测HCV（－）RNA是了解HCV复制的有效手段。本研究采用HCV负链RNA检测法检查5例慢性活动性丙型肝炎病人的肝组织及10例慢性活动性肝炎病人的血浆及淋巴－单核细胞。HCV负链RNA在前者均被检出，但在后者未被检出。将一份HCV负链RNA阳性的肝组织提取液作10－2稀释后仍可测得阳性结果，说明肝脏为HCV复制的主要器官；该方法可用于疑难病人肝穿刺标本的检测及其它研究。     

The P2X7R-NLRP3 and AIM2 Inflammasome Platforms Mark the Complexity/Severity of Viral or Metabolic Liver Damage

P2X7R-NLRP3 and AIM2 inflammasomes activate caspase-1 and the release of cytokines involved in viral-related liver disease. Little is known about their role in non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steato-hepatitis (NASH). We characterized the role of inflammasomes in NAFLD, NASH, and HCV. Gene expression and subcellular localization of P2X7R/P2X4R-NLRP3 and AIM2 inflammasome components were examined in histopathological preparations of 46 patients with biopsy-proven viral and metabolic liver disease using real-time PCR and immunofluorescence. P2X7R, P2X4R, and Caspase-1 are two- to five-fold more expressed in patients with NAFLD/NASH associated with chronic HCV infection than those with metabolic damage only (p ≤ 0.01 for all comparisons). The AIM2 inflammasome is 4.4 times more expressed in patients with chronic HCV infection, regardless of coexistent metabolic abnormalities (p = 0.0006). IL-2, a cytokine playing a pivotal role during chronic HCV infection, showed a similar expression in HCV and NASH patients (p = 0.77) but was virtually absent in NAFLD. The P2X7R-NLRP3 complex prevailed in infiltrating macrophages, while AIM2 was localized in Kupffer cells. Caspase-1 expression correlated with elastography-based liver fibrosis (r = 0.35, p = 0.02), whereas P2X7R, P2X4R, NRLP3, Caspase-1, and IL-2 expression correlated with circulating markers of disease severity. P2X7R and P2X4R play a major role in liver inflammation accompanying chronic HCV infection, especially when combined with metabolic damage, while AIM2 is specifically expressed in chronic viral hepatitis. We describe for the first time the hepatic expression of IL-2 in NASH, so far considered a peculiarity of HCV-related liver damage.     

Heads or Tails: Genotyping of Hepatitis C Virus Concerning the 2k/1b Circulating Recombinant Form

As different hepatitis C virus (HCV) genotypes respond differently to initiated therapy, correct HCV genotyping is essential. A potential risk for misclassification of the intergenotypic HCV circulating recombinant form (CRF) 2k/1b strains exists, depending on the genotyping method used. The aim was to investigate the differences in HCV genotyping methods with regard to CRF 2k/1b and to gain insight in the prevalence of the CRF 2k/1b. Genotyping results by Versant HCV Genotype Assay were compared with nonstructural protein 5B (NS5B) sequencing. In total, from November 2001 until March 2015, 3296 serum samples were analyzed by Versant HCV Genotype Assay. As misclassified CRF is harbored among HCV genotype 2, we further focused our search on 142 (4.3%) samples positive for HCV genotype 2. On 116 (81.7%) retrieved samples, the NS5B sequencing was performed. Twelve out of the 116 retrieved samples (10.3%) were classified as CRF 2k/1b by sequencing of the NS5B region. Ten of these 12 samples were originally misclassified as genotype 2a or 2c, while 2 of them were misclassified as genotype 2. Our results show that the current prevalence of CRF 2k/1b is underestimated. The importance of correct HCV genotyping is emphasized, considering the tailored choice of treatment regimen and overall prognosis.     

HCV核心抗原N-端片段生物素化表达质粒的构建及表达

目的构建HCV核心(C)抗原N-端1～130aa片段的生物素化表达质粒,并在大肠杆菌中进行表达。方法PCR扩增HCV C抗原N-端1～130aa片段的编码基因,拼接上生物素-蛋白连接酶底物肽序列(BSP),构建重组原核表达质粒pGEX4T-1-CN130BSP,转化大肠杆菌Rosetta,IPTG诱导表达。表达产物经SDS-PAGE后,电转至硝酸纤维素膜上,以抗HCVC抗原的单克隆抗体和辣根过氧化物酶标记的亲和素对表达产物进行分析。结果PCR扩增出约466bp的目的基因片段;质粒pGEX4T-1-CN130BSP经PCR及双酶切鉴定,与预期结果一致,测序鉴定基因无突变;SDS-PAGE显示表达产物相对分子质量约为42000,22℃诱导16h可溶性表达产物含量较高;表达的重组蛋白可被抗HCV C抗原的单克隆抗体所识别,并能特异性结合辣根过氧化物酶标记的亲和素。结论已成功构建了HCV C抗原N-端1～130aa片段生物素化表达质粒,并表达出带生物素标签的GST融合蛋白,为进一步研制HCV双抗原夹心检测试剂奠定了基础。     

丙型肝炎病毒F蛋白在病毒复制和致病中的作用

丙型肝炎病毒(Hepatitis C virus,HCV)属于黄病毒科,是有包膜的单正链RNA病毒.HCV基因组约有9 600个碱基,编码的单一开放读码框(Open reading frame,ORF)翻译出约3 000个氨基酸残基的多聚蛋白前体,在宿主细胞及病毒蛋白酶的作用下,剪切成至少10种结构蛋白和非结构蛋白.近...     

Difluoromethylornithine (DFMO), an Inhibitor of Polyamine Biosynthesis,and Antioxidant N-Acetylcysteine Potentiate Immune Response in Mice to the Recombinant Hepatitis C Virus NS5B Protein

Hepatitis C virus (HCV) is one of the main triggers of chronic liver disease. Despite tremendous progress in the HCV field, there is still no vaccine against this virus. Potential vaccines can be based on its recombinant proteins. To increase the humoral and, especially, cellular immune response to them, more effective adjuvants are needed. Here, we evaluated a panel of compounds as potential adjuvants using the HCV NS5B protein as an immunogen. These compounds included inhibitors of polyamine biosynthesis and urea cycle, the mTOR pathway, antioxidants, and cellular receptors. A pronounced stimulation of cell proliferation and interferon-γ (IFN-γ) secretion in response to concanavalin A was shown for antioxidant N-acetylcysteine (NAC), polyamine biosynthesis inhibitor 2-difluoromethylornithine (DFMO), and TLR9 agonist CpG ODN 1826 (CpG). Their usage during the immunization of mice with the recombinant NS5B protein significantly increased antibody titers, enhanced lymphocyte proliferation and IFN-γ production. NAC and CpG decreased relative Treg numbers; CpG increased the number of myeloid-derived suppressor cells (MDSCs), whereas neither NAC nor DFMO affected MDSC counts. NAC and DFMO suppressed NO and interleukin 10 (IL-10) production by splenocytes, while DFMO increased the levels of IL-12. This is the first evidence of immunomodulatory activity of NAC and DFMO during prophylactic immunization against infectious diseases.     

几家HCV抗体诊断试剂盒检测系列血清的比较

应用Abbott、UBI及国内几家的HCV第二代抗体诊断试剂盒A、B、c及D检测25名HCV感染者的210份感染后不同时期的系列血清,首次采用ELISA及RIBA分片段检测抗体,并与敏感的PCR法检测血清中HCV RNA结果相比较。虽然各试剂盒的总体检测符合率无显著性差异,但个别国产试剂盒的早期检测能力尚有待提高。用任何一家抗体检测试剂盒均会漏检小部分标本,抗体检测阴性的血清在100000倍稀释后仍可检出HCV RNA,因此,有必要发展包括更多片段包被的第三代HCV抗体诊断试剂盒。     

重组丙型肝炎病毒腺病毒载体疫苗rAd/E2的构建及鉴定

目的构建含丙型肝炎病毒(Hepatitis C virus,HCV)E2基因的复制缺陷型重组腺病毒载体疫苗,并进行鉴定。方法以含HCV(1a亚型)E2基因的质粒pEGFP-HCV/E1E2为模板,PCR扩增E2基因,扩增产物与pGEM-T载体连接,测序正确后双酶切亚克隆至穿梭质粒pAdTrack-CMV上,构建重组穿梭质粒pAdTrack-CMV/E2,Pme I酶切线性化后,与骨架质粒pAdEasy-1在BJ5183细菌内同源重组,获得重组腺病毒质粒pAd/E2,PacⅠ酶切线性化后,脂质体LipofectamineTM 2000介导转染HEK293细胞进行包装,获得重组腺病毒rAd/E2,在HEK293细胞内扩增,利用报告基因GFP的表达监测病毒包装及感染效率,PCR、RT-PCR和Western blot对重组腺病毒进行鉴定,并测定各代病毒的滴度。结果测序结果证明HCV E2基因序列正确;重组腺病毒质粒pAd/E2经酶切证明重组成功;PCR、RT-PCR及Western blot结果均证实重组腺病毒rAd/E2构建正确;第4代重组腺病毒的滴度为7.5×108 pfu/ml。结论已成功构建了重组HCV腺病毒rAd/E2,为丙型肝炎疫苗的研制提供了新的途径。     

丙型肝炎病毒非结构区NS5基因片段的克隆和表达

从抗 HCV和HCVRNA均为阳性的病人血清中 ,采用RT PCR技术扩增得到HCVNS5基因片段。用含此基因片段的重组质粒pET 2 8a转化大肠杆菌BL2 1(DE3)后可高效表达NS5蛋白。该蛋白可用固定化金属离子螯合层析法 (IMAC)纯化。经Westernblot和ELISA检测结果表明 ,纯化的NS5蛋白可与丙型肝炎患者血清发生特异反应 ,在HCV感染的诊断中可能具有良好的应用前景。