CVB3-VP1基因免疫诱导特异性抗病毒免疫应答及保护作用

目的 :构建表达柯萨奇病毒B3(CVB3)主要包膜蛋白VP1的基因疫苗 ,并研究该疫苗诱导CVB3特异性免疫应答及免疫保护的作用。方法 :抽提CVB3RNA ,以RT PCR扩增VP1基因 ,克隆于真核表达载体 pcDNA3中 ,构建质粒pcDNA3 VP1。将该质粒转染Hela细胞 ,观察其表达情况 ;以 5 0 μgpcDNA3 VP1质粒DNA肌注免疫BALB/c小鼠 3次 ,检测CVB3特异性体液和细胞免疫应答。间隔 4wk以 5×LD50 的CVB3攻击小鼠 ,观察攻击后小鼠的存活情况。结果 :构建了重组质粒 pcDNA3 VP1,并在体外获得有效表达。以该质粒肌肉免疫BALB/c小鼠 ,可诱生高水平的IgM和IgG ,VP1多肽特异性淋巴细胞增殖反应及CTL活性均显著高于 pcDNA3免疫的对照组。病毒攻击试验表明 ,pcDNA3 VP1免疫组33.3%小鼠可长期存活 ,其心肌组织未见明显的病理学改变 ;而对照小鼠平均仅存活 6 .7d ,心肌显示大量的局灶性坏死和炎性细胞浸润。结论 :pcDNA3 VP1免疫可诱生CVB3特异性体液及细胞免疫应答 ,保护免疫小鼠抵抗CVB3的致死性攻击     

接头长度对MDC与CVB3VP1融合基因疫苗免疫效果的影响

目的构建表达不同接头（linker）长度的巨噬细胞源趋化因子（MDC）与CVB3VP1融合基因疫苗，观察接头长度对融合基因疫苗免疫效果的影响。方法构建表达接头长度分别为10、15和19个氨基酸的重组质粒pcDNA3／MDC-L-VP1；将6—8周龄雄性BALB/c小鼠随机分为A-E5组，分别肌肉注射pcDNA3、pcDNA3／VP1、pcDNA3／MDC-L10-VP1、pcDNA3／MDC-L15-VP1和pcDNA3／MDC-L19-VP1，每次接种100μg/只，4周注射1次，共3次，每次免疫后第14天眼眶静脉采血，用微量中和试验滴定血清中和抗体效价。第3次免疫后3周，每组取3只小鼠，制备脾细胞，用CCK-8法检测特异性CTL杀伤活性；每组取3只小鼠以3LD50 CVB3病毒攻击，第7天取血处死，检测血中病毒滴度。结果成功构建了3种不同接头长度的质粒；第3次免疫后，E组中和抗体滴度和小鼠脾淋巴细胞特异性CTL杀伤活性显著高于其他各组，血中病毒滴度显著低于其他各组（P〈0．01）。结论融合基因疫苗pcDNA3／MDC-L19-VP1能诱导小鼠对CVB3VP1产生较强的体液和细胞免疫，有效地抑制了病毒的增殖。     

Chitosan-DNA基因免疫诱导粘膜特异性免疫应答及其抗CVB3感染作用

目的：构建新型粘膜基因疫苗，诱生CVB3VP1特异性粘膜免疫应答，探讨粘膜免疫抗CVB3感染的作用，为病毒性心肌炎的特异性防治奠定基础。方法：抽提CVB3 RNA，以RT-PCR扩增得VP1基因，插入真核表达载体pcDNA3中，构建质粒pcDNA3-VP1，以Chitosan多糖包裹形成Chitosan-DNA基因疫苗。将该质粒转染Hela细胞，观察其体外表达情况。以50辉DNA剂量的Chitosan-DNA疫苗滴鼻免疫BALB／C小鼠3次，检测CVB3特异性体液和细胞免疫应答；隔4周以5LD50活CVB3致死攻击小鼠，观察攻击后存活情况。结果：制备了直径为80-100nm的Chitosan-DNA复合物颗粒，体外转染证实Chitosan-DNA复合物中VPl的表达高于pcDNA3-VP1质粒-Lipofectamine的表达水平。该疫苗滴鼻3次免疫后，不仅诱生了高水平的IgG，而且诱生了高水平的粘膜IgA抗体，第6周抗体P/N值分别达3．5和3．2。特异性细胞免疫应答研究发现，该疫苗诱生了较强的VP1特异性CTL杀伤作用，并显著高于pcDNA3-VP1和pcDNA3组。CVB3攻击后，可保护33．3％小鼠长期存活，而pcDNA3和pcDNA3-VP1质粒滴鼻免疫对照组的平均存活天数分别为8．5和10．8天。病理学研究显示：Chitosan-DNA免疫小鼠心肌组织基本正常，而对照小鼠死亡前心肌显示大量的灶性坏死和炎性浸润。结论：Chitosan-DNA基因疫苗滴鼻免疫可诱生CVB3特异性粘膜IgA应答及CTL反应，具有一定的抗CVB感染的免疫保护力。     

柯萨奇病毒B组3型亚单位疫苗与基因靶向疫苗免疫小鼠的效果比较

目的:观察柯萨奇病毒VP1基因靶向核酸疫苗pcDNA3/C3d3-sVP1、重组腺病毒rAd/C3d3-sVP1和亚单位疫苗VP1蛋白的免疫效果。方法:雄性BALB/c小鼠随机分为4组,每组18只,分别肌肉注射PBS、pcDNA3/C3d3-sVP1、rAd/C3d3-sVP1和VP1蛋白,除重组腺病毒rAd/C3d3-sVP1组免疫2次,间隔2周外,其余3组均免疫3次,间隔3周。质粒每次每只接种100μg/100μl,腺病毒每次每只接种1.2×107pfu/100μl,蛋白每次每只接种50μg。分别用ELISA法和微量中和试验法检测血清CVB3 VP1特异性IgG抗体和中和抗体;CCK-8法检测脾淋巴细胞特异性CTL杀伤活性;以致死量的CVB3病毒液感染已免疫小鼠,检测小鼠血中病毒滴度,观察存活情况以评价各种疫苗的免疫保护作用。结果:各实验组小鼠的特异性IgG抗体和中和抗体滴度随免疫次数增加而提高,末次免疫后,VP1蛋白组的特异性IgG抗体和中和抗体滴度均明显高于pcDNA3/C3d3-sVP1组和rAd/C3d3-sVP1组(P<0.05),但rAd/C3d3-sVP1组CTL杀伤活性高于pcDNA3/C3d3-sVP1组和VP1蛋白组;经致死量CVB3感染后,VP1蛋白组血中病毒滴度低于其他实验组,而生存率明显高于其他各组。结论:VP1蛋白疫苗诱导小鼠产生较强的特异性免疫应答,提高了小鼠的生存率,免疫效果优于靶向基因疫苗pcDNA3/C3d3-sVP1和rAd/C3d3-sVP1。     

小鼠β防御素2与柯萨奇病毒B3 VP1融合基因疫苗的构建和免疫效果研究

目的:构建小鼠β-防御素2(Mouse beta-defensin-2,mBD2)与柯萨奇病毒B组3型(Coxsackievirus B3,CVB3)VP1融合基因疫苗,并观察其对小鼠的免疫效果.方法:克隆mBD2基因,构建重组质粒pcDNA3/mBD2和pcDNA3/mBD2-L-VP1.将4～6周龄BALB/c雄性小鼠随机分为5组,分别于股四头肌注射PBS(A组)、pcDNA3(B组)、pcDNA3/mBD2(C组)、pcDNA3/VP1(D组)、pcDNA3/mBD2-L-VP1(E组),每次接种剂量100 μg/只,3周免疫1次,共3次.每次免疫后第14天眼眶静脉取血,用微量中和试验滴定血清中和抗体效价.第三次免疫后第21天,每组随机取3只小鼠,制备脾淋巴细胞悬液,用CCK-8细胞计数法检测特异性CTL的杀伤活性;每组取3只小鼠以3LD50 CVB3病毒攻击,第7天取血处死,检测血清病毒滴度.结果:成功克隆了mBD2基因,构建了pcDNA3/mBD2和pcDNA3/mBD2-L-VP1两种重组质粒;D组和E组血清中和抗体滴度随免疫次数增加而提高(P＜0.01);E组血清中和抗体滴度和脾细胞特异性CTL杀伤活性显著高于其他组(P＜0.01),血中CVB3病毒滴度显著低于其他组(P＜0.01).结论:pcDNA3/mBD2-L-VP1能诱导小鼠对CVB3产生较强的体液免疫和细胞免疫,能有效抑制病毒在体内增殖.     

CVB3腺病毒载体Ad/sVP1-C3d3的构建及免疫效果研究

目的:构建柯萨奇病毒B3(CVB3)VP1基因重组腺病毒Ad/sVP1-C3d3,并观察对小鼠的免疫效果。方法:利用AdEasy-1系统构建、包装重组腺病毒Ad/sVP1-C3d3。BALB/c小鼠随机分为Ad/sVP1-C3d3、Ad/VP1、Ad和PBS4组,肌肉注射免疫,共免疫2次,每次间隔16d。用ELISA法和微量中和试验法分别检测血清CVB3VP1IgG和中和抗体滴度;CCK-8法检测特异性CTL杀伤活性;用致死量CVB3攻击小鼠后,检测血中病毒滴度。结果:成功构建、包装了重组腺病毒Ad/sVP1-C3d3。免疫小鼠后,Ad/sVP1-C3d3组血清CVB3VP1IgG滴度和中和抗体水平明显高于Ad/VP1(P<0.01),CTL杀伤活性明显高于Ad和PBS对照组(P<0.01)及Ad/VP1组(P<0.05),血清病毒滴度低于Ad和PBS对照组(P<0.05)。结论:重组腺病毒Ad/sVP1-C3d3能明显提高小鼠的细胞和体液免疫应答并降低血液病毒载量。     

柯萨奇B3病毒结构和非结构蛋白DNA 疫苗诱导小鼠产生免疫应答的研究

目的 制备4种柯萨奇B3病毒（CVB3）结构和非结构蛋白重组质粒DNA疫苗,并探讨其诱导机体产生体液和细胞免疫应答的效果。方法 用基因重组技术构建4种CVB3结构和非结构蛋白重组质粒,将各重组质粒体外转染真核细胞,用Western blot检测表达产物;于BALB／c小鼠后腿胫骨前肌注射免疫,于0、4、8周共免疫3次,100μg/次。免疫后不同时间检测体液和细胞免疫应答指标。结果 4种重组质粒酶切出相应大小的片段,经测序证实为CVB3序列,Western blot证实能够在体外真核细胞中表达。pcDNA3/vp2、pcDNA3/VP1、pcDNA3/2A和pcDNA3/3D均可诱导小鼠产生相应的特异性抗体、细胞毒性T淋巴细胞（CTL）和淋巴细胞增殖反应、迟发型超敏反应（DTH）,并对致死量的CVB3m、CVB5和CVB2攻击具有保护作用,表现为病毒攻击后第3天血中病毒滴度降低,第10天心肌病理变化比对照组明显减轻,且小鼠生存率显著提高。其中以pcDNA/VP1和pcDNA3／3D组保护作用最明显。结论 CVB3结构蛋白VP1和非结构蛋白3D质粒DNA有可能用作CVB DNA疫苗的候选基因,值得进一步深入研究。     

CVB3VP1核酸疫苗与重组腺病毒Ad/VP1联合应用的免疫效果

目的:观察柯萨奇病毒B3(Coxsackievirus group B type 3,CVB3)VP1核酸疫苗pcDNA3/VP1与重组腺病毒Ad/VP1联合应用的免疫效果。方法:大量制备pcDNA3/VP1和Ad/VP1,肌肉注射免疫小鼠。4～6周龄雄性BALB/c小鼠随机分为4组:质粒组,注射pcDNA3/VP1,共3次;腺病毒组,注射Ad/VP1,共2次;质粒/腺病毒组,第1、2次注射pcDNA3/VP1,第3次注射Ad/VP1;PBS对照组。各次注射间隔时间为3周。质粒每次接种100μg/只,腺病毒每次接种4×107pfu/只。用微量中和试验和ELISA法分别检测每次免疫后血清中和抗体和IgG抗体滴度;CCK-8法检测淋巴细胞增殖活性和CTL杀伤活性;用致死量病毒感染后检测血中病毒滴度,并观察小鼠的生存情况。结果:各实验组小鼠的中和抗体和IgG抗体水平均随免疫次数增加而提高,末次免疫后,质粒/腺病毒组血清中和抗体和特异性IgG抗体滴度(31.70±1.41,2425.15±1.86)明显高于质粒组(23.78±1.37,918.96±1.36)和腺病毒组(18.88±1.22,800.00±1.63)(P0.05);各实验组淋巴细胞增殖活性和CTL杀伤活性高于PBS对照组(P0.05);以致死量病毒感染后,质粒/腺病毒组血清病毒滴度低于其他组(P0.05),生存率高于其他组(P0.05)。结论:核酸疫苗与重组腺病毒联合应用可以明显提高免疫效果。     

CVB3腺病毒载体疫苗Ad/VP1的构建及免疫效果研究

 目的 构建柯萨奇病毒B3(coxsackievirus B3,CVB3)VP1基因重组腺病毒疫苗Ad/VP1,并观察其对小鼠的免疫效果。方法 利用AdEasy-1系统构建、包装重组腺病毒Ad/VP1,并检测目的蛋白的表达。BALB/c小鼠随机分为Ad/VP1、Ad和PBS 3组,肌肉注射免疫,共免疫2次,每次间隔16d。用ELISA法和微量中和试验法分别检测血清CVB3 VP1 IgG和中和抗体滴度;CCK-8法检测特异性CTL杀伤活性;用致死量CVB3攻击小鼠后,检测血中病毒滴度并观察小鼠的存活率。结果 成功构建、包装了重组腺病毒Ad/VP1,并在293细胞中检测到VP1蛋白的表达。免疫小鼠后,Ad/VP1组血清CVB3 VP1 IgG滴度、中和抗体水平明显高于PBS和Ad对照组(P<0.01),CTL杀伤活性和对小鼠的保护率也高于对照组(P<0.05),血清病毒滴度低于两对照组(P<0.05)。结论 重组腺病毒疫苗Ad/VP1能显著提高小鼠的细胞和体液免疫应答及免疫保护作用。     

iNOS基因和iNOS-VP1融合基因真核表达载体的构建及初步表达

目的 构建pcDNA3．1介导的诱导性一氧化氮合成酶（iNOS）的基因表达载体和pcDNA3．1介导的iNOS与柯萨奇病毒B组3型（CVB3）结构蛋白VP1融和基因的表达载体。方法 应用PCR扩增和DNA重组技术构建pcDNA3．1-iNOS和pcDNA3．1-iNOS—VP1表达载体；应用真核细胞转染技术及间接免疫荧光技术进行所构建的真核表达载体的初步表达和鉴定。结果 经PCR扩增技术用特异引物从质粒pKSiNOS分离编码iNOS开放阅读框架的cDNA，TA克隆于pMD19-T载体，根据设计引物时加入的酶切位点将插入片断亚克隆于表达载体pcDNA3．1；经PCR扩增技术用特异引物从质粒pCR2．1-VP1分离编码CVB3VP1结构蛋白的cDNA，TA克隆于pMD19-T载体，根据设计引物时加入的酶切位点将VP1亚克隆于iNOS的表达载体pcDNA3．1-iNOS，从而构建含有iNOS和VP1融合基因的真核表达载体。限制性内切酶分析、PCR鉴定和测序证实重组体peDNA3．1-iNOS和peDNA3．1-iN—OS—VP1插入片断的大小和方向正确且开放阅读框架的读码框不变；重组质粒peDNA3．1-iNOS和peDNA3．1-iNOS．VP1在HeLa细胞中均有表达，但表达效率较低。结论 获得含iNOS基因和iNOS—VP1融合基因的真核表达载体，并将重组质粒进行了初步表达，为体外iNOS抗CVB3作用的研究奠定了物质基础。     

DNA banking: the effects of storage of blood and isolated DNA on the integrity of DNA

Long-term storage of DNA is required for a number of genetic studies; prior to extraction, blood samples may be subject to elevated temperatures for variable intervals. We have studied the effect of temperatures ranging from -70 degrees C to +65 degrees C on human blood and on DNA extracted from it. DNA in solution stored at ambient temperatures up to 37 degrees C for 6 months was digestible by three different restriction endonucleases, whereas storage at 45 degrees C is deleterious after 6-7 weeks. DNA can be extracted from blood samples stored at -70 degrees C for at least 2 months or at 23 degrees C for a week or more, but blood stored at these temperatures may yield less high-molecular-weight DNA. Cell pellets from which plasma has been removed also can serve as a source of DNA. Isolated DNA stored dry for years (up to 30) is difficult to dissolve and may appear degraded, but a sample stored dry for 13 years and then in solution at -20 degrees C for 7 years appeared to be intact.     

Induction of DNA damage by urethane in mouse testes: DNA binding and unscheduled DNA synthesis

The extent and persistence of DMA damage and repair were investigated in mouse spermatogenic cells exposed in vivo to urethane (ethyl carbamate, EC). Adult male mice exposed to [³H]EC at 10–1,000 mg/kg were sacrificed 12 hr later. EC/metabolite binding to liver and testicular DNA and to sperm heads from the vasa deferentia was measured. Other male mice were exposed to EC at 50–750 mg/kg, and unscheduled DNA synthesis (UDS) induction was investigated in early spermatid stages. Similar experiments were conducted with vinyl carbamate (VC; putative EC metabolite) at 10–75 mg/kg. [³H]EC bound to liver and testicular DNA and to whole sperm heads. Testicular DNA binding increased linearly with dose, although binding was at least 2 orders of magnitude lower than with liver DNA. Sperm head binding also increased linearly with dose. Dose response studies with the UDS assay showed that EC and VC induced a small but significant increase of the UDS response in early spermatid stages. However, the induced UDS responses were quite variable and did not consistently increase with the administered dose. To determine the time kinetics of UDS induction, [³H]dThd was injected at various times after treatment with 500 mg/kg of EC or 60 mg/kg of VC. A slight but significant UDS increase was observed 4 hr after treatment with EC but not with VC. Overall, these results suggest that EC metabolites bind to testis DNA and cause low-level DNA damage in mouse sper-matogenic cells. This type of DNA damage apparently does not have significant genetic consequences. © 1994 Wiley-Liss, Inc.     

Immunochemistry of DNA

Since the first reports of anti-DNA antibodies in sera of patients with systemic lupus erythematosus (SLE) in 1957, studies of nucleic acid immunochemistry have grown in two directions. One has been the analysis of the specificity, the nature and the origins of these autoantibodies. The second has been exploration of anti-nucleic acid antibodies that can be induced experimentally, their specificities, and their application as biochemical reagents. Although the properties of autoantibodies and experimentally induced antibodies differ in certain respects, these two lines of research are complementary and provide important information for each other. For example, the production of autoantibodies by adjuvant-stimulated B cells yields a background that has to be considered in evaluating the specificity of weak responses to experimental nucleic acid immunogens: in turn, the possibilities and limitations of experimental immunization should be considered in evaluating possible stimuli for autoantibody production. Several aspects of nucleic acid immunochemistry have been described and evaluated in previous reviews. Following some general statements of historical perspective, this review will emphasize questions addressed and findings of about the last five years.     

Preferential recognition of specific DNA motifs by anti-double-stranded DNA autoantibodies

Although antibodies (Ab) specific for double-stranded (ds) DNA are thought to be involved in the etiopathogenesis of systemic lupus erythematosus (SLE), the fine structure of their DNA targets remains elusive. We have adapted a polymerase chain reaction (PCR)-assisted immunoprecipitation method to define the binding sites in DNA sequences recognized by high affinity anti-dsDNA Ab of SLE patients. SLE sera were used to bind templates from a pool of double-stranded oligonucleotides (ON). A central part of 20 base-pair random sequence was flanked by restriction endonuclease recognition sites and sequences complementary to predefined PCR primers. Immunoselected ON were precipitated, isolated from the immune complexes and then subjected to a further immunoprecipitation step after amplification by PCR. After five cycles of immunoprecipitation and PCR, the resulting ON were cloned. Sequence analysis revealed that sera from SLE patients and two human monoclonal anti-dsDNA Ab obtained from SLE patients preferentially select sequences expected to form non-B-DNA structures. Inhibition studies of the Farr assay confirmed the increased affinity of the selected epitopes for anti-DNA Ab as compared to random B-DNA.     

Collinear relationships of Herpesvirus Papio DNA to Epstein-Barr Virus DNA

Herpesvirus Papio (HVP) and Epstein-Barr virus (EBV) share both biological and biochemical properties. Since the linkage map of HVP and B95 EBV DNA are now available, the individual restriction fragments of HVP DNA were used as probes to determine the region of DNA homology between the two viral DNAs. In general, a high degree of collinearity was found between HVP DNA and B95 EBV DNA. There are only four small portions of B95 EBV DNA which did not show any homology by blot hybridization, i.e., the center region (EcoR1 K and part of Sal1 C of B95 DNA), the EcoR1 J region of B95 EBV DNA, and the terminal heterogeneous regions. The results also confirmed our previous data that the homologous sequences of HVP DNA to B95 EBV DNA are scattered throughout most of B95 EBV genome.     

The characterization of Gardnerella vaginalis DNA using non-radioactive DNA probes

DNA restriction profiles of various Gardnerella vaginalis isolates, generated by BamHI, EcoRI, PstI and other restriction enzymes, varied considerably. Only a few DNA fragments were identified as common in ethidium bromide fluorescence profile and Southern-blot hybridization patterns (employing a digoxigenin-labelled G. vaginalis DNA probe and an enzyme-linked immunoassay detection method). While the efficiencies of Southern-blot hybridization appeared inconsistent, in dot-blot assays, DNA from each isolate hybridized readily, enabling the detection of at least 10 ng DNA. A 5.7-kb DNA fragment from G. vaginalis ATCC 14018 genomic library, cloned in the BamHI site of pBR322, could replace the total genomic DNA probe. This specific DNA fragment was present in different sizes in 12 analysed G. vaginalis strains, describing a restriction fragment length polymorphism. In control studies, none of the DNA from bacteria other than G. vaginalis (including some genitourinary tract residents) hybridized with the G. vaginalis total or specific DNA probes. Non-radioactive G. vaginalis DNA probes can thus form the basis of a useful detection method for further studies of this organism.     

Vaccinia DNA: Separation of viral from host cell DNA

Summary Virus and cell DNA were separated by isopycnic centrifugation after subjecting a mixture to denaturation and reannealing. Virus DNA renatured, while cell DNA retained the density of single-stranded material. This process magnified the originally very small density difference between the two DNA's. The method's usefulness was demonstrated with mixtures of pure virus DNA and pure cell DNA, and was applied to the study of DNA synthesis in vaccinia infected cells.Supported by Stiftung Volkswagenwerk and Deutsche Forschungsgemeinschaft (We 165/3).On leave of absence from the Carnegie Institute of Washington.     

Presence of DNA in rubella variant with DNA polymerase activity

Summary Rubella variant with DNA polymerase which is formed as a result of recombination between rubella virus and a retrovirus of BHK21/WI-2 cells, contains both RNA and DNA in its virion.With 1 Figure