表达HBV preS2S基因重组MVA假病毒颗粒的构建及抗原性鉴定

目的构建携带HBV preS2S基因的重组MVA假病毒颗粒,评价其抗原性。方法将HBV preS2S基因通过基因重组构建入穿梭载体pSC11,得到质粒pSC11-preS2S,将此质粒转染MVA病毒通过同源重组得到MVA—preS2S,通过免疫印迹法鉴定其抗原性。结果利用基因测序,PCR鉴定证实所得假病毒颗粒可以表达HBV preS2S基因,并且具有良好的抗原性,经过9次传代得到单克隆重组病毒。结论本试验成功地构建了表达HBV preS2S基因的重组MVA假病毒颗粒MVA-preS2S,为基因治疗HBV慢性感染做了一项实验性奠基工作。     

CD/5-FC自杀基因体系在正常免疫力动物体内的抑瘤及旁观者效应

目的:观察阳离子脂质体介导的CD/5-FC自杀基因体系协同γ-IFN在正常免疫力小型动物体内对肿瘤的抑制效应及远端旁观者效应.方法:采用阳离子脂质体介导CD基因质粒瞬时转染小鼠肝癌H22及空质粒转染的H22细胞,分别接种于KM鼠双侧前腋下皮下;向小鼠体内注射5-FC及γ-IFN,观察在γ-IFN协同作用下对转染CD基因瘤体的抑制作用和远距离空质粒转染瘤体的抑制即远端旁观者效应.结果:5-FC对转染CD基因侧瘤体抑制明显,抑制率为79.39%;在γ-IFN的协同下CD/5-FC的抑瘤作用得到了增强,抑制率为93.47%,与无γ-IFN协同作用相比,对癌细胞抑制率明显增强(t=3.49,P=0.0036);存在远端旁观者效应,远端未转染瘤体的抑制率为54.42%;在γ-IFN的协同下远端旁观者效应得到显著增强,抑制率达到88.43%,同无γ-IFN相比有差异有显著性(t=2.86,P=0.0212).结论:体内CD/5-FC自杀基因体系联合γ-IFN对肝癌细胞有更好的抑制效应,对肝癌的治疗有很好的应用前景.     

重组质粒pcDNA3．1S2S／Fc在小鼠诱导免疫反应的观察

目的探讨S2S／Fc融合基因疫苗诱导小鼠HBV preS2S特异性体液和细胞免疫应答情况。方法取pcDNA3．1S2S/Fc、pcDNA3．1S2S＋pCMVsFc、pcDNA3．1S2S和空载体对照免疫BALB／c小鼠。在免疫动物2,4和6周后检测血清抗-HBs水平;在初次免疫7周后,测定免疫脾细胞的杀伤活性、增殖活性及细胞因子的分泌水平。结果经pcDNA3．1S2S／Fc免疫小鼠6周抗体滴度升至最高,免疫脾细胞的杀伤活性在效靶比为20：1时最高,免疫脾细胞的增殖活性以及IL-2和IFN-γ的分泌水平均比对照组明显增高。结论S2S／Fc融合基因在小鼠能诱导很强的特异性体液和细胞免疫应答。     

乙型肝炎病毒preS1基因真核表达载体的构建及表达

目的：构建含preS1基因真核表达质粒，探讨乙型肝炎病毒preS1基因在HBV入胞机制中的作用。方法：PCR法扩增含EcoR I与Pst I酶切点的preS1基因序列，PAS2-1载体及preS1基因PCR产物双酶切，经T4DNA连接酶将两者连接并转化到大肠杆菌JM105，对重组质粒经序列测定，命名为PAS 2—1—preS1。经乙酸锂转化法将重组质粒转化入酵母茵AH109，Western Blot法证实重组质粒在酵母细胞中的表达。结果：已构建的质粒PAS2—1-preS1经序列测定合有完整的preS1基因片段，转入酵母后经Western Blot证实酵母细胞正确表达preS1-BD融合蛋白。结论：PAS2—1—preS1的构建为通过酵母双杂交体系筛选体内与preS1蛋白相互作用的preS1相关蛋白，为进一步深入探讨preS1在HBV致病机制中的作用奠定了基础。     

HBV和HCV核酸疫苗的临床应用前景

核酸疫苗是指将含有编码抗原蛋白的DNA序列及必要的表达调控元件的重组质粒DNA直接导入机体组织，通过宿主细胞的转译系统表达目的抗原，诱导机体发生免疫应答的一种新型疫苗。近年来核酸疫苗的研究发展迅速，在乙型肝炎和丙型肝炎防治方面也取得了令人瞩目的成绩。1. HBV、HCV核酸疫苗的目的基因和载体：HBV有多种抗原蛋白编码基因。包括编码包膜蛋白的S基因、preS1基因、preS2基因，编码HBcAg和HBeAg的Ｃ基因等。包膜蛋白能诱导保护性抗体；HBcAg是CTL的靶抗原，其诱发的CTL应答有利于清除HBV，而HBeAg诱导抗HBe产生并减…     

弓形虫ROP2-SAG1重组复合蛋白及其重组质粒的免疫效应

目的研究弓形虫棒状体蛋白2(ROP2)和膜表面蛋白1(SAG1)重组复合抗原(ROP2-SAG1)的核酸和蛋白两种疫苗的免疫效应。方法 60只雌性BALB/c小鼠随机均分为4组(每组15只),即rROP2-SAG1蛋白组、无菌生理盐水组、pcROP2-SAG1质粒组和pcDNA3.1质粒组,rROP2-SAG1组以2.5μgrROP2-SAG1重组蛋白与等体积佐剂乳化后,背部皮下多点免疫小鼠;无菌生理盐水组以等体积无菌生理盐水替代重组蛋白,首次免疫使用福氏完全佐剂,其余使用福氏不完全佐剂。pcROP2-SAG1组和pcDNA3.1组分别以pcROP2-SAG1和空质粒pcDNA3.1腿部肌肉注射免疫,剂量为100μg/次;以上各组小鼠共免疫3次,每次间隔2周。采用间接ELISA方法检测免疫后25、45和70d小鼠血清中特异性IgG抗体,及末次免疫后2周小鼠血清特异性IgG1和IgG2a抗体。用CCK-8细胞增殖法检测小鼠脾细胞增殖,间接ELISA法检测小鼠脾细胞培养上清液中γ干扰素(IFN-γ)和白介素2(IL-2)表达水平。结果 rROP2-SAG1组小鼠血清特异性IgG抗体水平随着免疫时间的延长持续升高,pcROP2-SAG1质粒组抗体则随着免疫时间的延长相对稳定。末次免疫后2周,rROP2-SAG1组小鼠血清IgG1抗体水平(1.538±0.183)显著高于IgG2a(0.618±0.122)(P0.05),而pcROP2-SAG1组IgG1抗体水平(1.107±0.137)与IgG2a(0.830±0.185)间的差异无统计学意义(P0.05)。以特异性抗原rROP2-SAG1为刺激物时,rROP2-SAG1组小鼠脾细胞受特异性抗原刺激的增殖效果(A450值=0.348±0.042)显著高于pcROP2-SAG1组(0.123±0.018)(P0.05)。rROP2-SAG1组小鼠脾细胞培养上清液中IFN-γ含量[(149.37±30.51)pg/ml]、IL-2含量[38.58±9.10)pg/ml],分别与pcROP2-SAG1组IFN-γ[(138.58l±29.92)pg/ml]、IL-2[37.47l±9.26)pg/ml]比较,差异均无统计学意义(P0.05)。结论 ROP2-SAG1重组复合蛋白诱导的抗体水平、脾细胞增值效应显著高于重组质粒pcROP2-SAG1。     

融合基因S2S/IFNα对小鼠免疫反应的影响

目的探讨S2S/IFNα融合基因疫苗诱导HBV preS2S特异性体液免疫及细胞免疫应答的作用。方法pcDNA3.1S2S/IFNα作为实验组,设立pcDNA3.1S2S＋pcDNA3 IFNα组、pcDNA3.1S2S组及空载体对照组作为对照组,免疫BALB/c小鼠。采用0、2、4周的方案接种,检测各次接种后抗体水平。初次免疫后7周,测定免疫脾细胞的杀伤活性、增殖活性、细胞因子的分泌水平及免疫脾细胞CD25的表达量。结果pcDNA3.1S2S/IFNα组小鼠抗体滴度、免疫脾细胞的杀伤活性和增殖活性、Th1型细胞因子的分泌水平及CD25表达量均比对照组明显增强。结论S2S/IFNα融合基因能诱导更强的特异性体液免疫及细胞免疫应答。     

乙型肝炎病毒核心抗原与前S1抗原融合蛋白诱导小鼠免疫反应的实验研究

采用基因重组技术表达了去除C末端的HBV核心抗原和前S1抗原融合蛋白,经免疫印迹试验表明其具有特异抗原反应 性[1]。进一步用该融合抗原免疫BALB/C小鼠,观察其诱导小鼠特异性体液免疫产生情况。 一、材料与方法 1.重组型HBV核心前S1融合蛋白疫苗(HBV CS1)的     

小鼠对乙肝病毒小基因嵌合DNA疫苗免疫应答

目的:探讨含CD80的乙肝病毒小基因嵌合DNA疫苗的免疫应答.方法:以乙肝病毒小基因嵌合DNA疫苗pcHBV-CD80(含CMV启动子、HBV-preS2片段、HBV-C片段和CD80)、pcHBV(含CMV启动子、HBV-preS2片段、HBV-C片段),以及质粒pcDNA-CD80、pcDNA3.1和生理盐水,im免疫小鼠2次(间隔2 wk),末次接种后2 wk时检测特异性抗体、γ-IFN水平和淋巴细胞转化率.结果:质粒pcHBV-CD80和pcHBV免疫后均可检测到特异性的抗体,抗-preS2在pcHBV-CD80组和DcHBV组分别为1 5125.52 nkat/L和14463.56 nkat/L;抗-HB c在pcHBV-CD80组和DcHBV组分别为7607.35 nkat/L和7711.21 nkat/L,两组间无明显差异;但p cHBV-CD80更能增加γ-IFN的产生(1266.7 ng/L vs 986.3 ng/L,P＜0.01),并增强免疫小鼠的激淋巴细胞转化.结论:含CD80的乙肝病毒小基因嵌合DNA疫苗可诱导特异性的体液免疫和细胞免疫应答.     

乙型肝炎病毒基因疫苗诱导小鼠产生免疫应答的效应

目的 :构建编码乙型肝炎病毒 (HBV)表面蛋白S的重组质粒pCR 3 .1 S,将之直接肌肉注射balb/c小鼠 ,观察小鼠HBV特异的免疫应答。方法 :以ELISA法检测小鼠血清 ,3H TdR掺入法测定淋巴细胞增殖 ,51 Cr 4h释放法检测淋巴细胞杀伤功能。结果 :与空载体对照组相比较 ,基因疫苗诱发小鼠产生良好的抗HBs反应及HBV特异的细胞免疫应答 (P <0 .0 5)。结论 :基因疫苗pCR 3 .1 S可诱导balb/c小鼠产生全面的免疫应答     

DNA疫苗诱导健康小鼠抗-HBs产生的实验研究

目的　初步评价DNA疫苗诱导健康小鼠体液免疫应答效果。方法　应用基因重组技术构建编码乙型肝炎病毒(HBV)中蛋白(preS     

Antigenic and immunogenic changes due to mutation of s gene of HBV

AIM: To investigate the change of immunological characteristics of HBsAg caused by the mutation at codon 145 of HBsAg using DNA-based immunization. METHODS: Plasmids expressing mutant and wild type envelope antigens were transfected into human hepatocellular carcinoma cells via electrotransformation. The antigenicity of HBsAg was studied with EIA and immunocytochemical staining. Then plasmids were used to immunize 5 C57BL/6 mice. Sera of mice were detected for anti-HBs and anti-preS2 with ELISA. RESULTS: The mutant HBsAg could be detected by native antibody in EIA and immunocytochemical study. But the A((450 nm)) value of the mutant HBsAg in the supernatant was apparently lower than that of the wild-type. Both mutant and native HBsAg expression plasmid could stimulate a strong humoral immune response to HBsAg and preS2 antigen in mice. Protective antibodies against HBsAg elicited by the native HBsAg occurred earlier than that elicited by the mutant HBsAg about one to two weeks. The occurrence of protective antibodies against preS2 antigen was one to two weeks earlier than that of anti-HBs. CONCLUSION: The amino acid substitution causes changes of the antigenicity and immunogenicity of HBsAg, but mutant HBsAg can still induce a protective humoral immune response in mice.     

重组日本血吸虫P14蛋白对血吸虫感染小鼠保护性免疫效果

目的 目的 探讨重组日本血吸虫P14蛋白 （SjP14） 对血吸虫感染小鼠的免疫保护效果。方法 方法 构建SjP14原核表达质粒pET28a （+） ? SjP14, 异丙基?β?D?硫代半乳糖苷诱导表达重组蛋白rSjP14, 纯化蛋白后, 进行十二烷基磺酸钠?聚丙烯酰胺凝胶电泳 （SDS?PAGE） 和Western blotting鉴定。将6周龄雌性BALB/c小鼠随机分为SjP14重组蛋白实验组 （A组）、 佐剂对照组 （B组）、 生理盐水对照组 （C组）, 每组10只。每鼠每次注射抗原100 μg, 免疫3次, 每次间隔2周, 末次免疫后2周, 血吸虫尾蚴攻击感染。分别于免疫前、 免疫后6周和感染后6周经眶静脉采血, 分离血清, 采用酶联免疫吸附试验 （ELISA） 检测血清总IgG、 IL?4和IFN?γ。血吸虫尾蚴攻击感染后6周, 剖杀小鼠, 计算各组的减虫率和肝脏减卵率。结果 结果 SjP14原核表达产物相对分子质量 （Mr） 约为38 000; rSjP14能被SjP14多克隆抗体识别。血吸虫尾蚴攻击感染后6周, A组特异性IgG抗体水平升高, 为 （25.52±1.91）μg/ml, 与C组 ［（18.65±3.16）μg/ml］ 和B组 ［（22.44±2.83）μg/ml］ 相比差异均有统计学意义 （P 均＜0.05）。IFN?γ浓度升高, 为 （171.30±70.12）ng/L, 与C组 ［（136.89±37.62）ng/L］ 和B组 ［（153.64±43.44）ng/L］ 相比差异均有统计学意义 （P均＜0.05）。A组免疫后6周IL?4先略有升高, 感染后6周下降, 为 （112.05±15.02） ng/L, 与C组 ［（102.82± 27.46）ng/L］ 相比差异有统计学意义 （P＜0.05）。A组小鼠减虫率和减卵率分别为29.2%和41.3%, 与B、 C组相比差异均有统计学意义 （P均＜0.05）。结论 结论 SjP14蛋白疫苗具有一定的抗血吸虫感染免疫保护作用。     

结核杆菌DNA疫苗pVS84与pIL2质粒联合免疫的保护效率研究

目的用构建的人hIL-2质粒和结核杆菌DNA疫苗pVS84联合免疫后,对小鼠的细胞因子进行了测定并对抗结核分枝杆菌H37Rv攻击的能力进行了评估。方法将hil-2插入pVAX1,构建了人hIL-2的质粒pIL2。将雌性C57BL/6鼠分成6组,分别用pVS84和pIL2各50μg,pVS84,pVAX1,pIL2S和PBS免疫3次,间隔2周,加强免疫2次。另一组用BCG(105CFU)皮内免疫1次。每组10只鼠在最后一次加强后,取脾培养,检测上清细胞因子。另10只用结核菌H37Rv攻击,2周后取脾、肝和肺培养结核菌并计数。结果pVS84+pIL2联合免疫组的鼠血清hIL-2平均浓度为720.5±114.5pg/ml,显著高于其它组。pVS84+pIL2组、pVS84组的脾细胞培养上清的mIL-2和mIFN-γ平均含量显著高于3个阴性对照组(P<0.001),与BCG免疫组无显著性差异(P>0.05)。pVS84+pIL2组脾、肝和肺的平均结核菌载量分别为12471.4±2269.3,13622.6±2404.0和14742.0±2378.7CFU/g,低于pVS84组和3个阴性对照组相应器官的结核菌载量(P<0.001),与BCG对照组无显著差异。结论pIL2质粒与pVS84联合免疫能够刺激机体产生Th1型免疫应答,抵抗H37Rv攻击的能力与BCG的效果相当。     

负载食管癌抗原的DC诱导特异性CTL对食管癌细胞体外杀伤作用观察

目的观察负载食管癌抗原的树突状细胞（DC）活化的特异性细胞毒性T淋巴细胞（CTLs）对食管癌细胞的体外杀伤作用。方法冻融法获取食管癌细胞抗原,联合应用粒细胞—巨噬细胞集落刺激因子（rhGM-CSF）、白细胞介素4（IL-4）和肿瘤坏死因子α（TNF-α）诱导培养外周血DC并负载肿瘤抗原,激活自体T淋巴细胞,制备特异性CTLs。将其加入食管癌细胞中培养48 h,用MTT法检测食管癌细胞裂解率,ELISA法检测γ干扰素（γ-IFN）水平。结果负载食管癌抗原的DC激活的CTLs表现出对食管癌Eca109细胞的特异性杀伤作用,γ-IFN水平为（1 625±37.55）pg/ml;而对A549细胞仅有微弱的杀伤作用,γ-IFN水平为（169.04±13.81）pg/ml。未负载食管癌抗原DC刺激的CTLs对食管癌细胞几无杀伤作用。结论负载食管癌抗原的DC激活的CTLs在体外对食管癌细胞能产生高效而特异性的杀伤作用。     

Cloning of HBsAg-encoded genes in different vectors and their expression in eukaryotic cells

AIM: To compare the efficiency of different plasmids as DNA vectors by cloning three HBsAg-encoded genes into two eukaryotic expression vectors, pRc/CMV and pSG5UTPL/Flag, and to express HBsAg S, MS, and LS proteins in SP2/0 cells, and to establish monoclone SP2/0 cell strains that are capable of expressing S or S2S proteins stably.METHODS: Segments of S, preS2-S, preS1-preS2-S genes of Hepatitis B virus were amplified by routine PCR and preS1-S fragment was amplified by Over-Lap Extension PCR. The amplified segments were cleaved with restricted endonuclease Hind Ⅲ/Not I followed by ligation with pRc/CMV, or BamHI/EcoR I followed by ligation with pSG5UTPL/Flag. After the plasmid vectors were cleaved with the correspond enzymes, the amplified segments were inserted into pRc/CMV or pSG5UTPL/Flag plasmid vectors with T4 DNA ligase. KOZAK sequence was added before the initial ATG code of each fragment using specific primer. The inserted segments in the recombinant plasmids were sequenced after subcloning. BALB/c mice myeloma cells(SP2/0 cell line) were transfected with the recombinant plasmids. The expressions of the different recombinants were compared by Western-blot, using a monoclonal anti-HBs antibody as the primary antibody and peroxidase-labeled multi-linker as the secondary. Stable SP2/0-pRc/CMV-S or SP2/0- pRc/CMV-MS clones were established through clone screening with G418.RESULTS: Fragments with anticipated size were harvested after PCR. After recombination and screening, the sequences of the inserted segments in the recombinants were confirmed to be S, preS2S, preS1-preS2S and preS1S encoding genes,determined by sequencing. The results of Western-blot hybridization were positive for the anticipated proteins.Among them, pRc/CMV-S or pRc/CMV-MS demonstrated the highest expressing their respective antigen.CONCLUSION: Eight recombinant plasmids expressing S,M, L or preSiS proteins are obtained. For hepatitis surface antigen expression in eukaryotic cells, the vector pRc/CMV is superior to pSG5UTPL/Flag, and pRc/CMV-S and pRc/CMV-MS are the most efficient in the pRc/CMV clones. SP2/0 cells stably expressing HBsAg are established, and may be used as target cells for evaluating the CTL activity of a DNA vaccine in vitro.     

Contribution of C3d-P28 repeats to enhancement of immune responses against HBV-preS2／S induced by gene immunization

AIM: To investigate whether P28 derived from C3d can enhance the immune response to HBV-preS2/S induced by directly injection of naked plasmids containing variable repeats of P28 and HBV-preS2/S in fusion form.METHODS: One to four copies of C3d-P28 coding gene,amplified by PCR and modified by restriction endonuclease sdigestion, were subcloned into a eukaryotic expression vector pVAON33 to construct pVAON33-P28, pVAON33-P28.2, pVAON33-P28.3 and pVAON33-P28.4 (pVAON33-P28.[1-4]). HBV-preS2/S coding sequence was then introduced into the pVAON33-P28.[1-4] and identified by both PCR and DNA sequencing. BALB/c mice were primed by intramuscular gene immunization with 100 μg different recombinant plasmids on day 0 and were boosted by subcutaneous inoculation with HBsAg protein (1 μg) 12 wk post-priming. The levels and avidity of specific IgG in sera collected at the indicated times from each group were determined by ELISA and NaSCN-displacement ELISA,respectively.RESULTS: HBsAg specific antibody response was elicited in groups primed with plasmids pVAON33-S2/S-P28.[1-4] and pVAON33-S2/S. However, the response against HBsAg in the groups primed with pVAON33-S2/S-P28.[1-4] was significantly higher than that in pVAON33-S2/S group, the highest level of the specific antibody response was observed in the groups primed with pVAON33-S2/S-P28.4 (P＜0.01).After secondary immunization with specific antigen, the acceleration of antibody levels was significantly higher and faster in the mice primed with DNA expressing preS2/S-P28 fusions than that with DNA expressing preS2/S only (P＜0.05).Interestingly, mice primed with DNA expressing preS2/S-P28.4 fusions maintained the highest levels of anti-HBs antibodies in all animals. The avidity assay showed that the avidity index (AI) collected at 18 wk from mice primed with pVAON33-S2/S-P28.3 and pVAON33-S2/S-P28.4 were significantly higher than that from preS2/S-DNA vaccinated mice (P＜0.01).CONCLUSION: Different repeats of C3d-P28 can enhance both humoral immune response and avidity maturation of specific antibodies induced by gene immunization, in which four copies of C3d-P28 may be necessary to achieve the most modest antibody response.     

乙型肝炎病毒转基因小鼠免疫耐受状态及血液生物化学指标的研究

目的 了解HBV转基因鼠HBV基因的复制表达和免疫耐受状态,为探讨乙型肝炎发病机制和抗HBV新药评价提供可靠的参考依据.方法 选取遗传背景相同的SPE级HBsAg阴性非转基因鼠和转基因鼠.化学发光法检测HBsAg、HBeAg、HBV DNA,ELISA检测前S1、HBcAg,肝组织行病理学检查,免疫组织化学染色检测不同时期转基因鼠肝HBsAg表达,流式细胞仪检测小鼠淋巴细胞增殖情况,酶联免疫斑点检测(ELISPOT)分泌IFNγ的T淋巴细胞斑点数,双色免疫荧光法检测脾细胞悬液和脾树突状细胞(DC)中Toll样受体(TLR)2和TLR9的表达.数据行t检验和F检验.结果 HBV转基因鼠可复制表达HBsAg、前S1、HBeAg、HBcAg和HBVDNA,而抗-HBs、抗-HBc、抗-HBe均阴性;肝组织无明显病理改变,肝细胞中HBsAg在胞质表达,HBcAg在胞核表达.HBsAg刺激后,HBV转基因鼠T淋巴细胞增殖能力为(697.6±67.3)cpm,显著低于非转基因鼠的(1315.5±191.6)cpm.经HBsAg刺激后,HBV转基因鼠脾细胞分泌IFNγ的T淋巴细胞斑点数为8.25±1.10,低于非转基因鼠的28.50±4.21(F=155.967,P=0.000).HBV转基因DC表达CD11c+、TLR2和TLR9与非转基因鼠比较,差异无统计学意义(均P＞0.05).在18日龄胎鼠和1日龄仔鼠肝组织观察到HBsAg表达.结论 HBV转基因鼠有HBV相关抗原表达,并对HBV相关抗原存在免疫耐受,其先天和获得性免疫功能均正常,类似于人类慢性HBV无症状携带者.HBV转基因鼠是比较理想的动物模型.