鼠疫耶尔森菌中国分离株菌体脂肪酸成分分析

目的 探讨利用脂肪酸组织对中国鼠疫耶尔森菌菌株进行分型的可能性,获得中国鼠疫耶尔森菌菌株脂肪酸组成的本底资料。方法 选择历年来从我国不同疫源地分离到的58株鼠疫耶尔森菌进行了菌体脂肪酸成分分析。并利用STATISTICA统计软件进行实验菌株的聚类分析。结果 中国鼠疫耶尔森菌菌株的主要脂肪酸分为16：0酸,环式17：0酸,3-羟基14：0酸和ω7c16:1酸以及十八碳单烯酸,与MIDI公司Sherlock系统的菌库中的数据存在一些差异。结论 实验菌株的脂肪酸成分极为接近,聚类图不能充分体现分离株在分离时间,地点以及生物型别上的差异。表明脂肪酸分析目前不适于鼠疫耶尔森菌的分型,根据实验结果,建立了中国鼠疫耶尔森菌菌株的脂肪权组成数据库。     

口服鼠疫F1-V重组融合基因DNA活菌疫苗的构建及免疫原性研究

目的 构建携带鼠疫耶尔森菌F1-V融合基因的重组减毒沙门菌苗,口服免疫Balb/c小鼠检测其免疫原性,为口服鼠疫活载体DNA疫苗研究打下基础.方法 将F1-V融合基因克隆到真核表达载体asd-pVAX1,进一步依次将重组质粒转化减毒沙门菌X3730、X4550得到重组沙门菌X4550(asd-pVAX1/F1-V),提取重组质粒转染COS-7细胞并做免疫组化和Western-blot检测F1-V融合蛋白在细胞中的表达.以1×109CFU/只的剂量3次口服免疫Balb/c小鼠,ELISA方法检测血清中抗体水平.结果 构建的重组减毒沙门菌转染COS-7细胞后,免疫组化和Western-blot试验证明F1-V融合蛋白在细胞中得到了瞬时表达,ELISA检测到免疫小鼠血清有特异性抗体IgG产生.结论 构建的重组沙门菌能运送DNA疫苗到体内并成功释放质粒刺激机体产生特异性免疫应答,为口服鼠疫活载体DNA疫苗的黏膜免疫研究打下了基础.     

鼠疫耶尔森菌F1抗原的纯化方法改进及其免疫原性的评价

目的 建立从减毒鼠疫菌培养物中提取天然F1抗原的方法,评价F1抗原对鼠疫的免疫保护效果.方法 通过用玻璃珠裂解菌体替代有机溶剂的方法,结合饱和硫酸铵沉淀和凝胶过滤的方法从鼠疫菌培养物中纯化出天然F1抗原.将F1抗原吸附到25%氢氧化铝佐剂中,肌肉注射免疫BALB/c小鼠,于初次免疫后第18周皮下攻毒104 CFU活鼠疫菌141强毒株.结果 一次免疫的两个剂量组之间产生的抗体滴度差异无统计学意义,而加强免疫的两个剂量组中,F1-40 μg剂量组产生的抗体滴度明显高于F1-20μg剂量组.F1抗原免疫的小鼠全部存活,而且健康状况良好,对照组小鼠全部死亡.结论 本研究提供了一种简单、有效和便于大规模提取F1抗原的方法.提取的F1抗原具有较高的免疫原性,可作为鼠疫亚单位疫苗的重要抗原组分用于鼠疫亚单位疫苗的研制.     

两种耶尔森氏菌对动物的致病和交叉免疫性试验

目的了解广东省鼠疫静息期小肠结肠炎、假结核耶尔森氏菌的致病和交叉免疫性。方法致病性试验：菌株分皮下注射、饮水感染昆明小鼠,观察其发病和死亡情况,然后剖检。交叉免疫性试验：提取假结核鼠株冻溶抗原加佐剂研磨免疫家兔,然后分别用小肠结肠炎0：3猪株和鼠疫菌EV76株攻毒。试验均设对照组。结果0：3猪株皮下注射小鼠5只全部死亡,饮水感染死亡3只,2只发病;0：9鼠株皮下注射死亡2只,饮水感染仅发病;假结核鼠株两种途径感染仅发病。假结核鼠株免疫的家兔能抵抗0：3猪株攻毒,用EV76株攻毒未能产生鼠疫F1抗体。结论0：3猪株毒力强,0：9鼠株弱,耶尔森氏菌对动物有交叉免疫力。     

检测鼠疫耶尔森菌LcrV抗体的上转换发光技术免疫层析试纸条的制备及应用

目的　本研究旨在制备一种用于检测鼠疫耶尔森菌LcrV抗体的上转换发光技术(UPT)免疫层析试纸条.方法　通过在试纸条分析膜检测带处固定抗原,质控带处固定抗体,结合垫位置半固定将上转换发光(UCP)颗粒标记的抗原,制备出了双抗原夹心模式的LcrV抗体检测UPT免疫层析试纸条.对制备成型后的试纸条进行了线性和灵敏度、准确性、及热稳定性4个方面的性能评价.最后用此试纸条检测了40份自然感染鼠疫的兔和人血清标本,并将结果与ELISA检测结果进行了比较.结果　试纸灵敏度达0.97 mg/L,对所测17份猴血清标本的检测准确度为100％,在37℃的稳定存放期为10d.试纸对40份实际血清标本的检测结果与ELISA检测结果一致.结论　试纸有良好的灵敏度和线性检测能力.     

鼠疫F1蛋白原核分泌性表达及鉴定

目的构建重组质粒,在大肠杆菌中表达鼠疫菌F1抗原。方法用PCR方法扩增出带有信号肽的F1基因,将其克隆到表达载体pET30a(+)上,转化大肠杆菌BL21(DE3);用IPTG诱导目的基因表达,层析方法纯化F1蛋白,测定其分子量、等电点、N末端氨基酸序列,用Westernblot法检测其抗原性。结果根据双酶切和DNA测序结果显示,F1基因成功连接到表达载体pET30a(+)中,F1蛋白主要为分泌性可溶表达。测定纯化后F1蛋白的相对分子量约为15.6kD,等电点为4.15,N末端氨基酸序列与理论序列一致。经Westernblot鉴定,能被兔抗鼠疫菌EV株血清识别。结论成功克隆并构建了F1蛋白分泌性原核表达系统,所表达的重组F1蛋白具有较好的抗原性,为新型鼠疫疫苗研制提供基础。     

鼠疫耶尔森氏菌Pla蛋白单克隆抗体的制备与鉴定

目的:利用原核表达的鼠疫耶尔森氏菌Pla蛋白(rPla),通过杂交瘤细胞技术制备单克隆抗体(mAb),为相关研究工作奠定基础.方法:大肠杆菌表达的Pla蛋白,包涵体经尿素反复洗涤纯化后免疫BALB/c小鼠,取血清抗体效价高的小鼠脾细胞与Sp2/0骨髓瘤细胞进行细胞融合,以表达Pla、表达GST、天然提取Pla 3种蛋白为抗原物,采用间接ELISA法筛选阳性杂交瘤细胞,并结合Western blot对所获取mAb的特异性进行鉴定.结果:经间接ELISA筛选,获得3株能稳定分泌抗天然Pla蛋白mAb的杂交瘤细胞株,命名为15B8、14H4、19A4,亚类测定分别为IgG2a和IgG1,轻链均为κ链;腹水经间接ELISA法检测效价可达1:106:Western blot实验证实该3株mAb能特异性识别天然Pla蛋白.结论:成功获得了抗鼠疫耶尔森氏菌天然Pla抗原的特异性mAb,为进一步研究Pla蛋白及研发诊断试剂奠定了基础.     

问号钩端螺旋体脂蛋白LipL32膜定位及其免疫应答

目的 确定问号钩端螺旋体(简称钩体)属特异性脂蛋白抗原LipL32膜定位及其自然抗体应答情况和抗体类型.方法 IPTG诱导目的 重组蛋白rLipL32-1和rLipL32-2表达,Ni-NTA亲和层析法提纯rLipL32.采用显微镜凝集试验(MAT)检测四川地区钩体患者血清标本及rLipL32兔抗血清与我国问号钩体参考标准株的交叉凝集情况.采用胶体金免疫电镜技术对LipL32进行膜定位.建立基于rLipL32的ELISA,检测钩体患者血清中特异性抗体类型及其水平.结果 黄疸出血群是四川地区最主要的优势钩体血清群.rLipL32兔抗血清均能与我国问号钩体参考标准株发生MAT效价为1∶80～1∶320的交叉凝集反应.LipL32是位于钩体外膜表面的蛋白质分子.156例MAT阳性钩体患者血清标本中,rLipL32-1和rLipL32-2特异性IgM阳性率分别为91.0%～92.9%和90.4%～92.3%,特异性IgG阳性率分别为99.4%和97.4%～98.1%.结论 LipL32是问号钩体属特异性表面蛋白抗原.自然感染钩体时,LipL32-1和LipL32-2可诱导机体产生IgM和IgG两类血清抗体.rLipL32-1和rLipL32-2可作为研制检测试剂盒的候选抗原.     

神经元膜抗NMDAr1亚基IgG分子构象的原子力显微镜研究

目的　确定兔抗NMDAr1亚基 (N 甲基 D 天冬氨酸受体Nr1亚基 )IgG分子特征性构象。方法　应用原子力显微镜扫描生理状态下分布在云母表面的兔抗NMDAr1亚基蛋白IgG分子 ,并进行理论计算。结果　IgG分子为 136 .4 ×6 2 .8 × 2 6 .1 椭球形三亚基复合物。结论　原子力显微镜可以在生理状态下直观测定生物大分子纳米尺度介观结构。抗NMDAr1蛋白IgG分子的特征性构象 ,可以做为神经细胞膜表面NMDA受体 (N 甲基 D 天冬氨酸受体 )原子力显微镜观测的原位标记物     

嗜水气单胞菌抗独特型单克隆抗体的制备和初步鉴定

目的:制备嗜水气单胞菌(Aeromonas hydophila)抗独特型单克隆抗体(AId mAb)并进行鉴定.方法:以具有中和作用的抗嗜水气单胞菌 mAb 1G10免疫 BALB/c小鼠,采用常规杂交瘤技术制备嗜水气单胞菌 AId mAb.用 ELISA法对 mAb的效价及其模拟嗜水气单胞菌的特性进行鉴定.结果:获得4株能稳定分泌嗜水气单胞菌 AId mAb的杂交瘤细胞株,分别命名为1F9、 1H10、 3F5、 4G3.经测定杂交瘤细胞腹水 mAb效价为10 -4～10 -5.竞争抑制实验结果表明 4株 AId mAb均能不同程度地抑制嗜水气单胞菌与兔抗嗜水气单胞菌多克隆抗体结合,其中两株 1F9、 1H10具有较强的抑制作用.用作制备抗独特性抗体腹水的小鼠,其血清均能检测与嗜水气单胞菌进行免疫结合的抗体,经 ELISA检测,其效价为 1: 100 ～1: 1 000.结论:成功地制备了产生嗜水气单胞菌抗独特型抗体的杂交瘤细胞株,为制备该菌的抗独特性抗体疫苗奠定了基础.     

Anti-V antigen antibody protects macrophages from Yersinia pestis -induced cell death and promotes phagocytosis

The pathogenic Yersinia spp. harbor a common plasmid (pYV) essential for virulence. The plasmid encodes a type III secretion system that functions to translocate Yersinia outer proteins (Yops) into the host cytosol. Within the host cell, the Yops act to inhibit phagocytosis and induce apoptosis. One of the plasmid-encoded proteins, virulence antigen (V), is a major protective immunogen that is involved in Yop translocation. Yersinia pestis, like the enteric Yersinia spp., was both resistant to phagocytosis by and cytotoxic for J774.A1, a murine macrophage cell line. Both of these activities were dependent on culture of the bacteria at 37 degrees C for 1.5-2 h before infection. However, extending the preculture period at 37 degrees C to 24 h, which induced formation of a capsule, completely blocked cytotoxicity. Treating the bacteria with either rabbit polyclonal anti-V antibodies (R anti-V) or monoclonal antibody (MAb) 7.3, antibodies specific for V and protective against plague in vivo, protected J774.A1 cells from Y. pestis -induced cell death and also reversed the inhibition of phagocytosis. Whereas protection against cell cytotoxicity was afforded by the F(ab')(2) portion of R anti-V, the ability of anti-V to induce uptake of Y. pestis appeared to be dependent on the Fc portion of the Ab. The protective epitope(s) recognized by R anti-V was contained in the central region of Y. pestis V (aa 135-275) and were partially cross reactive with Y. pseudotuberculosis and Y. enterocolitica serotype 08 V antigens.     

Role of the Yersinia pestis Ail protein in preventing a protective polymorphonuclear leukocyte response during bubonic plague

The ability of Yersinia pestis to forestall the mammalian innate immune response is a fundamental aspect of plague pathogenesis. In this study, we examined the effect of Ail, a 17-kDa outer membrane protein that protects Y. pestis against complement-mediated lysis, on bubonic plague pathogenesis in mice and rats. The Y. pestis ail mutant was attenuated for virulence in both rodent models. The attenuation was greater in rats than in mice, which correlates with the ability of normal rat serum, but not mouse serum, to kill ail-negative Y. pestis in vitro. Intradermal infection with the ail mutant resulted in an atypical, subacute form of bubonic plague associated with extensive recruitment of polymorphonuclear leukocytes (PMN or neutrophils) to the site of infection in the draining lymph node and the formation of large purulent abscesses that contained the bacteria. Systemic spread and mortality were greatly attenuated, however, and a productive adaptive immune response was generated after high-dose challenge, as evidenced by high serum antibody levels against Y. pestis F1 antigen. The Y. pestis Ail protein is an important bubonic plague virulence factor that inhibits the innate immune response, in particular the recruitment of a protective PMN response to the infected lymph node.     

Mechanisms of long and short term immunity to plague

Long and short term immunity to plague was produced in normal mice by using, respectively, an antibiotic resistant Yersinia pestis and Yersinia pseudotuberculosis. Both immunogens were used live. Passive serum transfer experiments, together with assays for the bactericidal activity of macrophages and delayed hypersensitivity tests, showed that the short term immunity was of a humoral nature and the long term immunity was cell mediated. The plague virulence markers of the two immunogens were: Y. pestis VW- F1+ P1+ P+; Y. pseudotuberculosis VW+ F1- P1- P-. The challenge organism was Y. pestis VW+ F1+ P1+ P+.     

鼠疫耶尔森菌重组质粒pVAX1/Fl-V的构建及其免疫效果的研究

目的获得含有鼠疫F1和V抗原编码基因的重组真核表达质粒pVAX1／F1-V，并测定其诱导特异性免疫应答的能力。方法PCR扩增鼠疫菌Fl和V编码基因，分别与pGEM-T连接测序，构建pVAX1／F1-V融合重组质粒，转染Cos-7细胞，用Western blot方法鉴定目的蛋白的表达，重组质粒pVAXI／F1．V加GM．CSF佐剂免疫BALB／c小鼠，观察免疫效果，400个半数致死量（uk）强毒鼠疫菌皮下攻毒观察保护率。结果pVAX1／F1-V在Cos-7细胞中表达，免疫鼠体内产生特异性抗体，通过抗体亚型分析、细胞因子等指标的测定表明所构建DNA疫苗以诱发TH1型免疫为主，攻毒保护率达60％。结论成功构建F1-V融合蛋白真核表达载体，具有诱导特异性细胞免疫和体液免疫应答的能力，对强毒鼠疫菌皮下攻毒有一定的保护效力，为鼠疫菌新型疫苗研制奠定了基础。     

Role of fraction 1 antigen of Yersinia pestis in inhibition of phagocytosis

Yersinia pestis, the causative agent of plague, expresses a capsule-like antigen, fraction 1 (F1), at 37 degrees C. F1 is encoded by the caf1 gene located on the large 100-kb pFra plasmid, which is unique to Y. pestis. F1 is a surface polymer composed of a protein subunit, Caf1, with a molecular mass of 15.5 kDa. The secretion and assembly of F1 require the caf1M and caf1A genes, which are homologous to the chaperone and usher protein families required for biogenesis of pili. F1 has been implicated to be involved in the ability of Y. pestis to prevent uptake by macrophages. In this study we addressed the role of F1 antigen in inhibition of phagocytosis by the macrophage-like cell line J774. The Y. pestis strain EV76 was found to be highly resistant to uptake by J774 cells. An in-frame deletion of the caf1M gene of the Y. pestis strain EV76 was constructed and found to be unable to express F1 polymer on the bacterial surface. This strain had a somewhat lowered ability to prevent uptake by J774 cells. Strain EV76C, which is cured for the virulence plasmid common to the pathogenic Yersinia species, was, as expected, much reduced in its ability to resist uptake. A strain lacking both the virulence plasmid and caf1M was even further hampered in the ability to prevent uptake and, in this case, essentially all bacteria (95%) were phagocytosed. Thus, F1 and the virulence plasmid-encoded type III system act in concert to make Y. pestis highly resistant to uptake by phagocytes. In contrast to the type III effector proteins YopE and YopH, F1 did not have any influence on the general phagocytic ability of J774 cells. Expression of F1 also reduced the number of bacteria that interacted with the macrophages. This suggests that F1 prevents uptake by interfering at the level of receptor interaction in the phagocytosis process.     

Polyaniline-dacron composite as solid phase in enzyme linked immunosorbent assay for Yersinia pestis antibody detection

Polyaniline (PANI) was chemically synthesized on a dacron disk surface and an antigen (F1 fraction) obtained from Yersinia pestis was covalently fixed onto this composite via glutaraldehyde. The enzyme linked immunosorbent assay (ELISA) or rapid ELISA procedure detected immunoglobulin G (IgG) anti-F1 fraction in human serum employing this derivative. The appropriate conditions for carrying out the test were established as an antigen concentration of 2 microg/PANI-dacron disk, peroxidase labeled goat anti-human IgG conjugate diluted 4000 times, and a serum dilution of 1:100. The PANI-dacron disks showed greater antigen retention than conventional poly(vinyl chloride) plates and less antibody unspecific adsorption.     

应用胶体金层析法快速检测鼠疫耶尔森氏菌F1抗原

目的研究胶体金免疫层析法用于鼠疫耶尔森菌的快速诊断。方法采用胶体金免疫层析测试条,加入待测鼠疫耶尔森菌液及对照菌液。结果金标免疫层析试纸条在检测中并未出现交叉反应,特异性达到100％,显示其在鼠疫耶尔森菌的检测中特异性较好,结果可靠。同时该试纸条敏感性亦较高,少量细菌或抗原就可得到阳性结果,检测效果好。结论该方法简便、快速、敏感、特异性好,适合于公共突发卫生事件中的鼠疫快速诊断和现场鼠疫监测。     

Expression of the Yersinia pestis capsular antigen (F1 antigen) on the surface of an aroA mutant of Salmonella typhimurium induces high levels of protection against plague.

The caf operon from Yersinia pestis encoding the structural subunit (caf1), the molecular chaperone (caf1M), the outer membrane anchor (caf1A), and the regulatory protein (caf1R) was cloned into Salmonella typhimurium SL3261 aroA. The recombinant Salmonella organisms were encapsulated when cultured at 37 degrees C but not when cultured at 28 degrees C. Oral inoculation of mice with the recombinant Salmonella induced predominantly an immunoglobulin G2a response to F1 antigen, and isolated T cells showed a recall response to soluble or Salmonella-associated F1 antigen. Mice immunized with S. typhimurium SL3261 aroA expressing F1 antigen intracellularly developed lower antibody responses to F1 antigen and showed a T-cell recall response only to Salmonella-associated F1 antigen. Mice immunized orally with two doses of the recombinant Salmonella which expressed F1 antigen on the surface were protected against 10(7) 50% lethal doses (LD50) of virulent Y. pestis given by the subcutaneous route of challenge, whereas mice immunized with the recombinant Salmonella expressing F1 antigen intracellularly were only partially protected against 10(5) LD50 of Y. pestis.     

Immunohistochemical detection of Yersinia pestis in formalin-fixed, paraffin-embedded tissue

Yersinia pestis infection usually is limited to lymph nodes (bubo); rarely, if bacteria are aerosolized, pneumonic plague occurs. We developed an immunohistochemical assay using a monoclonal anti-fraction 1 Y pestis antibody for formalin-fixed tissues. We studied 6 cases using this technique. Respiratory symptoms were prominent in 2 cases; histologically, one showed intra-alveolar inflammation, and the other had alveolar hemorrhage and edema. By using the immunohistochemical assay, we found intact Yersinia and granular bacterial antigen staining in alveoli, bronchi, and blood vessels. Of the remaining cases, 2 had septicemia and 2 had a bubo. Pathologic changes included lymphocyte depletion, necrosis, edema, and foamy macrophages in lymph nodes; multiple abscesses in the spleen; fibrin thrombi in glomeruli; and unremarkable lungs. By using the immunohistochemical assay, we identified intact bacteria inside monocytes and granular antigen staining in blood vessels. The immunohistochemical assay provided a fast, nonhazardous method for diagnosing plague. The immunohistochemical assay localizes bacteria, retaining tissue morphologic features, and can help define transmission mechanisms.     

Anti-LcrV antibody inhibits delivery of Yops by Yersinia pestis KIM5 by directly promoting phagocytosis

LcrV of Yersinia pestis is a major protective antigen proposed for inclusion in subunit plague vaccines. One way that anti-LcrV antibody is thought to protect is by inhibiting the delivery of toxins called Yops to host cells. The present study characterizes the relation between this inhibition and the phagocytosis of the bacteria. J774A.1 cells were infected with Y. pestis KIM5 in the presence of a protective polyclonal anti-LcrV antibody or a nonprotective polyclonal anti-YopM antibody, and delivery of YopH and YopE into the cytoplasm was assayed by immunoblotting. The ability to inhibit the delivery of these Yops depended upon having antibody bound to the cell surface; blocking conditions that prevented the binding of antibody to Fc receptors prevented the inhibition of Yop delivery. Anti-LcrV antibody also promoted phagocytosis of the yersiniae, whereas F(ab')(2) fragments did not. Further, anti-LcrV antibody could not inhibit the delivery of Yops into cells that were unable to phagocytose due to the presence of cytochalasin D. However, Yops were produced only by extracellular yersiniae. We hypothesize that anti-LcrV antibody does not directly inhibit Yop delivery but instead causes phagocytosis, with consequent inhibition of Yop protein production in the intracellular yersiniae. The prophagocytic effect of anti-LcrV antibody extended to mouse polymorphonuclear neutrophils (PMNs) in vitro, and PMNs were shown to be critical for protection: when PMNs in mice were ablated, the mice lost all ability to be protected by anti-LcrV antibody.