丙型肝炎病毒与恶性疟原虫复合多表位抗原基因在小鼠及家兔中免疫应答的研究

目的 :探讨丙型肝炎病毒 (HCV)及恶性疟原虫 (Pf)复合DNA疫苗的可行性。方法 :把HCV复合多表位抗原基因PCX与Pf复合基因AB克隆到带CMV启动子的真核表达载体pcDNA3中 ,构建真核表达载体pcDNA3 CAB ,肌肉注射免疫小鼠及家兔 ,检测其诱发特异性免疫应答水平及安全性。结果 :小鼠及家兔分别于免疫后第 6周及第 8周可检测到抗GZ PCX抗体 ,于第 10周达最高 ,滴度分别为 1:40 0及 1:3 2 0 0 ,但持续时间较短 ;免疫血清可识别Pf抗原 ;免疫动物还可产生针对GZ PCX融合蛋白的迟发性超敏反应 ;免疫后小鼠体重正常 ,肝脾脏未见明显肿大 ,具有良好的安全性。结论 :HCV Pf双价多表位DNA抗原基因在小鼠及家兔中可诱发特异性免疫应答 ,但抗体的持续时间较短。     

乙型肝炎病毒多表位抗原DNA疫苗的免疫原性

目的 :探讨HBV复合多表位DNA疫苗诱导体液及细胞免疫的可行性。方法 :将HBV多表位抗原基因BPT克隆到真核表达载体pcDNA3.1中 ,构建重组真核表达载体pcDNA3.1/BPT。将其通过肌肉注射免疫BALB/c小鼠 ,用间接免疫ELISA法、CTL杀伤功能检测和淋巴细胞增殖试验 ,检测特异性体液免疫和细胞免疫的水平 ,并观察其对免疫小鼠的毒副作用。结果 :用重组质粒pcDNA3.1/BPT免疫BALB/c小鼠后 ,在效靶比为 10 0∶1时 ,可诱导显著地特异性CTL应答 (P <0 .0 5 )。ELISA检测免疫小鼠血清特异性IgG的水平明显升高 (P <0 .0 5 )。在BPT基因原核表达蛋白的刺激下 ,免疫小鼠脾淋巴细胞增殖显著 (P <0 .0 5 )。RT PCR分析表明 ,IL 12mRNA的水平亦明显升高。结论 :HBV多表位基因疫苗可诱发特异性免疫应答 ,为预防、治疗性HBV疫苗的研制提供了一定的实验依据     

丙型肝炎病毒多表位疫苗研究的新进展

丙型肝炎病毒引起慢性肝脏疾病的主要原因之一,HCV疫苗一直是研究的热点.多表位疫苗是指通过筛选与组合优势抗原表位(包括T细胞、B细胞表位)的新型核酸疫苗,目的在于产生高效的细胞免疫和体液免疫应答进而清除病毒.其优势在于通过选择最具免疫保护潜力的表位以覆盖尽量多的病毒亚型和诱导机体全面的抗病毒免疫应答.现就近年来国内外在丙型肝炎病毒多表位疫苗的研究做一介绍.     

丙型肝炎病毒多表位抗原的原核表达及免疫原性分析

目的:研究丙型肝炎病毒(HCV)十表位抗原HCVe在大肠杆菌中的非融合表达及其免疫原性分析.方法:在大肠杆菌DH5α中表达非融合蛋白HCVe, 纯化该蛋白后利用Westerb blot分析其抗原反应性.免疫小鼠, 检测其免疫特异性.结果:HCVe十表位抗原能在原核表达系统中高效表达.Western blot和ELISA分析表明HCVe十表位抗原能与HCV病人阳性血清特异性结合, 并可诱发小鼠产生特异性HCV抗体.结论:表达的HCVe十表位抗原具有特异的抗原反应性及免疫原性.     

丙型肝炎病毒多表位抗原重组体免疫原性分析

目的：研究丙型肝炎病毒(HCV)多表位抗原重组体在大肠杆菌中的非融合表达及其免疫原性分析。方法：利用DNA重组技术将构建的HCV多表位抗原重组体克隆入原核表达载体pBV220并在BL-21中表达，非融合表达蛋白经SDS-PAGE检测，排阻层析纯化，利用ELISA和免疫印迹分析其抗原反应性。免疫昆明鼠和猕猴，并检测其抗体和特异性CTL(Cyto-toxic T lymphocyte)，在抗体转阴后再次用HCV病人血清攻击以检测其免疫应答能力。结果：HCV多表位重组体在pBV220／BL-21中表达量占菌体总蛋白量的15％。Western-blot和ELISA分析表明HCV多表位抗原能与HCV病人血清特异性结合，抗体水平和特异性CTL检测结果显示该抗原肽能诱导小鼠和猕猴产生较好的抗体水平和特异性CTL效应。用病人血清再次攻击后受试动物的抗体迅速阳转。结论：表达的多表位重组体具有特异的抗原反应性和免疫原性。     

乙型肝炎病毒治疗性多表位基因疫苗在小鼠中的免疫应答研究

目的:分析乙型肝炎病毒(HBV)重组多表位抗原基因在大肠杆菌中非融合表达的蛋白B-BPT的免疫原性,以期为HBV预防/治疗性疫苗的研制奠定实验基础。方法:构建重组质粒pBAD/BPT,并在大肠杆菌中诱导表达。以纯化的蛋白B-BPT免疫BALB/c小鼠,用乳酸脱氢酶(LDH)释放法检测该融合蛋白诱导的小鼠细胞毒T淋巴细胞(CTL)应答。用流式细胞术(FCM)检测小鼠CD4+、CD8+T淋巴细胞亚群的比例,用MTT比色法检测淋巴细胞的增殖效应。结果:B-BPT蛋白免疫BALB/c小鼠后,可诱导特异性CTL应答(P<0.05,与空白对照组比较);B-BPT蛋白免疫后,可显著刺激小鼠脾淋巴细胞增值(P<0.05,与空白对照组比较)。结论:该非融合表达的蛋白B-BPT可有效地诱导小鼠特异性CTL免疫应答,为进一步研制乙肝预防治疗性疫苗奠定了基础。     

B细胞表位基因疫苗诱导特异性免疫应答及特性研究

为研究特异性B细胞表位短肽为基础的DNA疫苗的免疫应答特性,将鸭乙肝病毒Pre-S中的P127-138B细胞表位基因克隆到含多肽表达盒(peptideexpressioncassette,PEC)的载体中,体外转染C2C12肌肉细胞,用DOT-EIA检测表位短肽的表达,进一步分别免疫不同品系的BALB/c和C57BL/6小鼠,比较MHC限制性对免疫应答的影响。结果表明,重组pECk-b1b2载体可在体外瞬时高效表达,并保持原有的免疫活性;体内基因免疫能诱导针对表位短肽的特异性抗体;不同品系小鼠抗体产生动力学相似,但抗体滴度差异显著。这些结果提示,以B细胞表位为基础的基因免疫可诱导特异性免疫应答,为DNA疫苗的分子设计提供了新的思路和应用前景。     

乙型肝炎病毒重组多表位抗原诱发的小鼠免疫应答

目的:对乙型肝炎病毒重组多表位抗原基因在大肠杆菌中表达的融合蛋白P/BPT进行免疫原性分析,以期为HBV预防/治疗性疫苗的研制奠定实验基础。方法:构建重组质粒pWR450-1/BPT,在大肠杆菌中诱导表达并纯化蛋白P/BPT,免疫BALB/c小鼠,乳酸脱氢酶释放法检测该融合蛋白诱导小鼠的细胞毒T淋巴细胞(CTL)应答,ELISA法检测小鼠血清抗-P/BPT抗体水平,流式细胞仪检测小鼠CD4+、CD8+T淋巴细胞亚群比例,用RT-PCR方法半定量检测细胞因子特异性mRNA,MTT法测淋巴细胞增殖效应。结果:P/BPT蛋白免疫后,效靶比为100:1时,可有效诱发特异性CTL应答(P<0.05);ELISA方法测出小鼠血清抗-P/BPTIgG明显升高(P<0.05);P/BPT蛋白免疫后,可显著刺激小鼠脾淋巴细胞增值(P<0.05);CD4+T淋巴细胞和细胞因子IFN-γ的增殖和分泌水平亦有明显升高。结论:该融合蛋白可有效诱导小鼠体液免疫和细胞免疫应答,为进一步研制乙肝预防治疗性疫苗奠定了初步基础。     

丙型肝炎病毒与恶性疟原虫复合多表位抗原基因在小？…

目的：探讨丙型肝炎病毒（ＨＣＶ）及恶性疟原虫（Ｐｆ）复合ＤＮＡ疫苗的可行性。方法：把ＨＣＶ复合多表位抗原基因ＰＣＸ与Ｐｆ复合基因ＡＢ克隆到带ＣＭＶ启动子的真核表达载体ｐｃＤＮＡ３中,构建真核表达载体ｐｃｄＤＮＡ３／ＣＡＢ,肌肉注射免疫小鼠及家兔,检测其诱发特异性免疫应答水平及安全性。结果：小鼠及家兔分别于免疫后第６周及第８中检测到抗ＧＺ－ＰＣＸ抗体,于第１０周达最高,滴度分别为１：４００及１：３２     

DNA免疫引起小鼠产生抗丙型肝炎病毒核壳区体液应答的初步研究

采用ｐｃＤＮＡ３与ｐＭＴ两种基因表达裁体，构建包含丙型肝炎病毒（ＨＣＶ）核心区（Ｃ区）或全结构基因区（核心区、包膜区）的质粒。经纯化后直接对Ｂａｌｂ／ｃ小鼠进行骨骼肌或尾部皮内注射，２～６ｗ后采血，用ＥＬＩＳＡ法检测小鼠抗核壳区的体液应答。结果表明：ＤＮＡ免疫可引起小鼠产生抗ＨＣＶ核壳区的体液应答，加强免疫２次后可使特异性抗体平均滴度达到１８００以上。提示ＤＮＡ免疫可作为丙型肝炎病毒感染的潜在防御手段。     

丙肝病毒(HCV)及乙肝病毒(HBV)双表达载体的构建及表达

目的 :为探索HCV/HBV高效联合基因免疫策略 ,构建具有 2套独立表达单元的HCV/HBV真核表达载体。方法 :分别将与HCV核心区基因互补的cDNA和HBV核心区基因克隆于具有 2套独立表达单元的真核表达载体pRSC的巨细胞病毒启动子和RSV启动子下游 ,称为pRSC HBV/HCV ,转染SP2 / 0细胞 ,通过免疫荧光和Western印迹法观测蛋白的表达 ,免疫Balb/c小鼠 ,用酶联免疫小鼠体液免疫应答。结果 :pRSC HBV/HCV转染SP2 / 0细胞可见HBcAg及HCV核蛋白染色阳性荧光细胞 ,SDS Page电泳显示在 14kD及 2 1kD处均可见蛋白条带 ,与HBcAg及HCV核蛋白的的理论预期值一致 ,Western印迹分析显示在 14kD及 2 1kD处可见特异性的蛋白条带。 5只免疫鼠中全部出现抗 HCV及抗 HBV抗体 ,而对照组全阴性。结论 :pRSC HBV/HCV可分别表达HBcAg及HCV核蛋白 ,免疫Balb/c小鼠后可诱导其体液免疫应答 ,为进一步开展HCV/HBV联合基因免疫奠定了实验基础。     

载体和基因片段的选择对戊型肝炎病毒基因免疫抗原表达的影响

目的比较不同载体和不同大小的目的基因片段对戊型肝炎病毒(HEV)基因免疫抗原表达的影响,为基于HEV中和抗原表位的HEV基因免疫提供一定的依据。方法将含Ⅳ型HEV中国株中和抗原表位的p166和p179片段编码基因分别克隆入pTR421和pCDNA3.1两种真核表达载体,用脂质体介导基因转染HepG2人肝癌细胞系,经间接免疫荧光和Western blot分析以及将质粒注射小鼠局部肌肉组织后经免疫组织化学染色检测,分析目的基因在体内外的表达水平。结果成功构建了pTR421-166、pTR421-179、pCDNA3.1-166和pCDNA3.1-179四种重组质粒,经限制性内切酶双酶切和核苷酸测序鉴定,编码基因正确无误;pTR421-179转染的细胞以及注射小鼠的局部肌肉组织可以检测到p179的表达,而pCDNA3.1-179、pCDNA3.1-166以及pTR421-166均检测不到目的基因在体内、外的抗原表达。结论载体和目的基因片段的选择显著影响HEV抗原在体内、外的表达,直接关系到基因免疫的成功与否。     

多型别HCV-E1复合表位抗原研究

目的 设计多型别HCV-E1表位复合免疫原,通过免疫小鼠,探讨其在丙型肝炎治疗性疫苗与诊断试剂研究中的应用.方法 分析比较HCV-E1包膜糖蛋白B细胞表位序列,选取几个代表性基因型的中和性优势抗原表位,再结合泛DR辅助性T细胞表位(PADRE),构建含有不同HCV型别E1表位抗原基因和通用T辅助细胞表位基因的原核表达质粒.结果 成功构建了含有HCV 1a、1b、2a、3a、4a和6a等基因型E1中和性表位以及通用T辅助细胞表位的质粒pBVIL1/E1s-PADRE,该质粒转化大肠杆菌后获得的工程菌,通过诱导培养可以高效表达重组多型别HCV-E1表位复合抗原,所获得的多型别HCV-E1表位复合免疫原可在BALB/c小鼠体内诱发强烈的体液免疫反应,ELISA检测抗体水平可达到1:12 800.结论 新构建的HCV-E1表位复合免疫原具有很好的免疫原性,为进一步研究HCV疫苗奠定了基础.     

Lack of anti-GOR antibody among subjects with GB virus C/hepatitis G virus RNA

Homologies were sought between the putative amino acid sequences of GB virus C/hepatitis G virus (GBV-C/HGV) and the GOR epitope or the liver/kidney microsome-1 (LKM-1) epitope, which share partial sequence identity with the hepatitis C virus (HCV) polyprotein. Anti-GOR antibody (anti-GOR) was assayed among 100 subjects with GBV-C/HGV RNA. Twenty-one and 25 subjects were coinfected with hepatitis B virus (HBV) or HCV, respectively. Homologies were found between the NS5 or E2 polyproteins of GBV-C/HGV and the GOR epitope or the LKM-1 epitope, respectively. These segments of GBV-C/HGV polyproteins sharing identity with the GOR or the LKM-1 epitope were well conserved among three genotypes of GBV-C/HGV. However, only 1 of 55 subjects (1.8%) with GBV-C/HGV RNA, but not with HBV or HCV, was positive for anti-GOR. The positivity for anti-GOR among the group with GBV-C/HGV RNA alone was significantly lower than that among the groups with HCV RNA (P < 0.01 and P < 0.05, respectively). Only 2 of 55 subjects (3.6%) with GBV-C/HGV RNA alone exhibited elevation of alanine aminotransferase. The incidence of liver dysfunction among the group with GBV-C/HGV RNA alone was significantly lower than the incidence among the groups with GBV-C/HGV RNA and hepatitis B surface antigen (HBsAg) or HCV RNA (P < 0.01 and P < 0.01, respectively). These data indicate that 1) there is no association between GBV-C/HGV infection and the presence of anti-GOR, and 2) GBV-C/HGV infection is not related to chronic liver dysfunction. J. Med. Virol. 55:129–133, 1998. © 1998 Wiley-Liss, Inc.     

Prominent proliferative response of peripheral blood mononuclear cells to a recombinant non-structural (NS3) protein of hepatitis C virus in patients with chronic hepatitis C.

The proliferative response of peripheral blood mononuclear cells (PBMC) to a recombinant non-structural (NS3) protein of hepatitis C virus (HCV) was studied in 41 patients with chronic hepatitis C. Of them, 28 had chronic persistent hepatitis (CPH) and 13 chronic active hepatitis (CAH). The positive proliferation rate of PBMC to the recombinant NS3 protein, T9Ag, was 66% in the 41 patients (77% in CAH versus 61% in CPH; P > 0.05) when stimulation index (SI) = 4 was set as the cut-off value. However, mean SI of CAH patients was significantly higher than that of CPH patients (8.3 +/- 5.2 versus 5.1 +/- 3.6; P < 0.05). Six other chronic hepatitis patients who were repeatedly negative for anti-HCV antibody but positive for serum HCV RNA also had an SI of > or = 4.0. The frequency of cellular immune response to the T9Ag is among the highest results obtained by using HCV antigens tested so far. Our studies thus indicate that NS3 is an immunologically important region of HCV for T cells. Moreover, the proliferative response to T9Ag may help to establish hepatitis C etiology in chronic hepatitis patients who are seronegative with currently available anti-HCV assays.     

Simultaneous detection of hepatitis C virus core antigen and antibodies in Saudi drug users using a novel assay

Drug users and particularly, injecting drug users, are at increased risk for infection with hepatitis C virus (HCV). The aims of the study were to simultaneously detect HCV core antigen and specific antibodies in sera from Saudi drug users using the new HCV combination assay and to compare this data with HCV core antigen, anti-HCV antibodies and HCV RNA data from the same patients. A total of 297 patients who are followed up or admitted to a drug rehabilitation hospital over a period of 3 years were included in this study. Samples were analyzed using the new HCV Ag/Ab combination assay (Meurex), HCV core Ag assay, HCV antibodies and with the HCV RNA assay. Out of the 297 samples from Saudi drug users, 111 samples (37.4%) have detectable HCV core Ag, 112 samples (37.7%) have detectable HCV antibodies, 118 have detectable HCV RNA, and 116 samples were positive by the HCV Ag/Ab combination assay (39.1%). Out of the 116 samples, HCV core Ag was detected in 110 samples (94.8%), HCV antibodies were detected in 111 (95.7%) samples and HCV RNA was detected in 114 samples (98.3%). In the control group (n = 305), only 2 (0.66%) blood donor were positive by HCV antibodies assay, HCV RNA assay as well as HCV Ag/Ab combination assay. The new HCV Ag/Ab combination assay may well improve the overall quality of diagnosis of HCV infection especially in high risk population such as drug users that necessitates rigorous testing.