布鲁氏菌野毒株A544与疫苗株104M的差异蛋白筛选

为给布鲁氏菌病自然感染与疫苗免疫鉴别方法的建立提供参考,采用比较蛋白质组学研究技术,以野毒株A544和疫苗株104M的菌体蛋白为研究对象,以双向电泳技术为分离手段,以基质辅助激光解吸飞行时间质谱为检测手段,利用生物学信息解析所得实验结果。双向电泳结果分析显示,野毒株A544和疫苗株104M之间约有20个差异蛋白点,经质谱成功鉴定了9种蛋白。通过蛋白数据库检索发现,这些蛋白主要参与了一些代谢调节等生物过程,其中有6个蛋白点在野毒株A544上高表达,3个蛋白点在疫苗株104M上高表达。     

一种新的检测牛种布鲁氏菌抗体的方法—荧光极化法（FPA）

目前检测牛种布鲁氏菌（Ｂｒｕｃｅｌａａｂｏｒｔｕｓ）抗体常用的血清学方法有缓冲平板抗原试验（ＢＰＡＴ）、补体结合试验（ＣＦＴ）、间接酶联免疫试验（Ｉ－ＥＬＩＳＡ）和竞争酶联免疫试验（Ｃ－ＥＬＩＳＡ）。本文介绍的荧光极化法（ｆｌｕｏｒｅｓｃｅｎｃｅｐｏ...     

布鲁氏菌BP26抗原胶体金试剂盒的研制及功能初试

目的：应用胶体金免疫层析技术建立一种快速检测布鲁氏菌抗体的方法,组装试剂盒并进行初步验证。方法：采用柠檬酸三钠还原法制备胶体金溶液,标记重组布鲁氏菌BP26抗原和兔抗BP26多抗血清包被在硝酸纤维素膜上分别作为检测线和质控线,确定标记的最佳pH和最佳标记抗原量,检测试剂盒的灵敏度和重复性。结果：该试剂盒最佳标记pH值为6.7,最佳标记抗原量为20 μl,试剂盒的灵敏度和重复性较好。结论：该试剂盒具有较好的灵敏度和重复性,整个检测过程可在15 min内完成,能够快速检测样品血清,适用于现场快速检测。     

运用免疫蛋白质组学方法筛选副猪嗜血杆菌血清4型菌株的免疫反应性蛋白

选取2株副猪嗜血杆菌血清4型菌株(A、B菌株),采用蛋白提纯和双向电泳技术获得高分辨率的蛋白胶。通过比对蛋白胶和免疫印迹膜上的蛋白反应点,并切取相应蛋白点进行质谱鉴定。根据质谱鉴定结果,菌株A和B有13个相同的蛋白点,其中8个蛋白点是新发现的具有免疫原性的蛋白点,它们分别是二氢硫辛酰胺脱氢酶(DLDH)、dppA、过氧化氢酶(CAT)、蛋白酶(P)、转酮醇酶(TK)、延长因子(EF-Ts)、周质丝氨酸蛋白水解酶(SP)、2,3-二磷酸甘油酸变位酶(BPGM)。在2株副猪嗜血杆菌血清4型菌株中发现有13个相同的免疫反应性蛋白,DLDH、dppA、CAT、P、TK、EF-Ts、SP和BPGM是新发现的免疫原性蛋白,它们作为疫苗候选抗原有待进一步研究。     

布鲁氏菌S19号菌苗免疫幼龄牦牛的免疫效果观察

布鲁氏菌S19号菌苗是一种对牛布布鲁氏菌具有良好免疫效果的生物制剂。鉴于其对成年牛免疫后抗体存留时间长而影响布鲁氏菌的常规监测，故许多国家和地区主要用于幼龄牛，并且只用1次即可获得终生免疫保护力。但截止目前尚未见对4－8月龄牦牛免疫效果的报道。为了在我省牦牛集中产区推广应用布鲁氏菌S19号菌苗，以控制部分县布鱼氏菌病回升的趋势，我们于1997－2000年在甘肃省张掖地区和甘南藏族自治州的6个牧业县进行了该菌苗的免疫试验和推广应用。     

布鲁氏菌致病及免疫机制研究进展

布鲁氏菌病是由布鲁氏菌属的细菌引起的人畜共患传染病 ,目前布鲁氏菌属的细菌主要有七个种。随着分子生物学技术的发展 ,对布鲁氏菌的致病机制在分子水平上有了更进一步的理解 :布鲁氏菌自身一些与致病有关的基因使得布鲁氏菌逃避了巨噬细胞的杀伤作用 ,在巨噬细胞内存活和定居。在布鲁氏菌病免疫过程中 ,先天性免疫应答主要通过补体、巨噬细胞、天然杀伤细胞来参与 ,获得性免疫应答中 ,CD4 、CD8 、rδT细胞起很重要的作用。文章围绕这些与致病、免疫有关的基因及参与免疫反应细胞的研究进展进行了探讨 ,可为今后进行布鲁氏菌病预防及开发新型基因工程苗提供理论依据。     

牛支原体免疫相关性蛋白硫锌酰胺脱氢酶的筛选与鉴定

为鉴定牛支原体(M.bovis)菌体免疫相关蛋白及其免疫原性,本实验以M.bovis湖北株为样品,通过建立M.bovis全菌蛋白的双向电泳体系,获得了分辨率及重复性良好的双向电泳(2-DE)图谱。利用western blot技术进行筛选,鉴定得到多个M.bovis蛋白,其中一个分子量为68 ku,经过质谱分析和氨基酸一级结构比对确定该蛋白为硫锌酰胺脱氢酶(LipDH)。经原核重组表达,LipDH重组蛋白与M.bovis阳性血清的western blot反应为阴性,而Dot blot及以重组表达蛋白作为包被抗原的ELISA鉴定结果均为阳性。本研究为进一步研究LipDH的功能以及采用其重组蛋白用于该蛋白缺失的M.bovis疫苗株的鉴别检测方法的建立奠定了基础。     

牛布鲁氏菌抗体荧光快速检测试纸卡的研制

为研制一种快速检测牛布鲁氏菌抗体的便捷试纸卡,采用间接荧光免疫层析技术,以荧光微球为标记物,与兔抗牛IgG偶联,以布鲁氏菌脂多糖（LPS）抗原包被硝酸纤维素膜,通过反应条件优化,研制牛布鲁氏菌抗体荧光微球快速检测试纸卡。结果显示：该试纸卡灵敏度可达0.8 IU/mL,与牛口蹄疫病毒O型、牛口蹄疫病毒A型、牛病毒性腹泻病毒、牛传染性鼻气管炎病毒的抗体阳性血清均无交叉反应;对469份临床牛血清进行检测,同时与荧光偏振方法进行比较,发现两种方法的符合率为100%。结果表明,本次研制的牛布鲁氏菌抗体荧光微球检测试纸卡灵敏度高,特异性好,适用于临床样品的快速检测。本试纸卡的成功研制为牛布鲁氏菌病免疫效果评估和准确诊断提供了一种简便的血清学诊断方法。     

流产布鲁氏菌omp25基因的克隆与原核表达

用设计的1对特异性引物对流产布鲁氏菌2型CVCC70502株总DNA进行外膜蛋白基因omp25的PCR扩增，得到了1条完整的基因，大小为642bp；测序分析证明，它与国外报道的流产布鲁氏菌omp25基因的核苷酸序列完全一致。将该基因克隆到原核表达载体pGEX-6p-1中，经酶切、PCR扩增和测序分析，表明重组表达载体构建成功。将此重组质粒转化至宿主菌BL21（DE3）中，用IPTG进行诱导。结果证实，该基因可以在大肠杆菌中表达，表达产物为分子质量约50ku的融合蛋白，与理论推测的蛋白分子质量一致；Western—blotting试验证明，表达蛋白OMP25可被流产布鲁氏菌阳性血清所识别。     

流产布鲁氏菌疫苗候选株RB6生物学特性研究

为了开发布鲁氏菌病新型标记疫苗,本研究对流产布鲁氏菌基因缺失株RB6的培养特性、染色特性、凝集特性、稳定性及小鼠体内毒力和免疫保护力进行了系统鉴定,旨在阐明该菌株具备的生物学特性。通过对亲本菌株和RB6的比较,发现固体培养基上RB6菌株单菌落可被结晶紫染成紫色,RB6菌株液体培养物可与0.1%吖啶黄染料以及抗布鲁氏菌粗糙型抗体发生凝集反应,证明该菌株为粗糙型。将RB6菌株在体外连续传代培养20次和牛体内连续5次继代,检测结果证明其表型未发生变化,说明该菌株遗传稳定性良好。通过小鼠体内试验发现该菌株毒力显著降低,并对流产布鲁氏菌强毒菌株2308攻毒的免疫保护力与现有疫苗A19接近。本研究结果表明,流产布鲁氏菌基因缺失株RB6为粗糙型菌株,毒力较低、安全性高、遗传性状稳定,并具有良好的免疫保护效力,有望开发成为动物布鲁氏菌病粗糙型标记疫苗。     

Cu/Zn SOD蛋白在布鲁菌S19疫苗株中的过表达及鉴定

以Cu/Zn SOD为目的基因,通过基因工程技术分别构建了组成型过表达系统pBBR-trc-sod和诱导型过表达系统pBBR-lacPtrc-sod,在布鲁菌S19疫苗株中进行了Cu/Zn SOD的过表达。同时,以大肠杆菌为宿主表达纯化的重组Cu/Zn SOD蛋白免疫家兔制备多克隆抗体,对2种过表达系统中Cu/Zn SOD蛋白的表达量进行分析。结果显示,诱导型Cu/Zn SOD过表达系统的表达量更高,且能与所制备的多抗发生特异性反应。结果表明,构建的过表达系统能够实现Cu/Zn SOD蛋白在布鲁菌S19疫苗株中过表达;同时,该试验也提示我们这种表达系统可应用于布鲁菌S19疫苗的抗原改造。     

Loop-mediated isothermal amplification (LAMP) test for specific and rapid detection of Brucella abortus in cattle

Background: Brucella abortus, the major causative agent of abortion in cattle and a zoonotic pathogen, needs to be diagnosed at an early stage. Loop-mediated isothermal amplification (LAMP) test is easy to perform and also promising to be adapted at field level.

Objective: To develop a LAMP assay for specific and rapid detection of B. abortus from clinical samples of cattle.

Methods: LAMP primers were designed targeting BruAb2_0168 region using specific software tool and LAMP was optimized. The developed LAMP was tested for its specificity with 3 Brucella spp. and 11 other non-Brucella spp. Sensitivity of the developed LAMP was also carried out with known quantity of DNA. Cattle whole blood samples and aborted fetal stomach contents were collected and used for testing with developed LAMP assay and results were compared with polymerase chain reaction (PCR).

Results: The developed LAMP assay works at 61 °C for 60 min and the detection limit was observed to be 100-fold more than the conventional PCR that is commonly used for diagnosis of B. abortus. Clinical sensitivity and specificity of the developed LAMP assay was 100% when compared with Rose Bengal plate test and standard tube agglutination test. SYB® green dye I was used to visualize the result with naked eye.

Conclusion: The novelty of the developed LAMP assay for specifically detecting B. abortus infection in cattle along with its inherent rapidness and high sensitivity can be employed for detecting this economically important pathogen of cattle at field level as well be exploited for screening of human infections.     

Use of Brucella abortus vaccine strain RB51 in pregnant cows after calfhood vaccination with strain 19 in Argentina

One hundred and seven pregnant cows, which had been calfhood vaccinated with Brucella abortus strain 19 (S-19) were revaccinated with either S-19 or strain RB51 (S-RB51). All S-19-revaccinated animals seroconverted, while none of the RB51-revaccinated animals seroconverted. Two out of 25 (8%) S-19-revaccinated animals aborted, while none of the 57 RB51-revaccinated group aborted. Four of the S-19-revaccinated animals shed S-19 in the milk for at least 7 days, while only 1 cow shed S-RB51 for at least 3 days (but <7 days) post-parturition. Revaccination of strain 19 calfhood-vaccinated, pregnant cattle with S-RB51 appears to be a safe procedure with no diagnostically negative consequences.     

Global metabolomic analysis of blood from mice infected with Brucella abortus

To better understanding Brucella abortus infection, serum metabolites of B. abortus-infected and -uninfected mice were analyzed and twenty-one metabolites were tentatively identified at 3 and 14 days post-infection (d.p.i.). Level of most lysophosphatidylcholines (LPCs) was found to increase in infected mice at 3 d.p.i., while it was decreased at 14 d.p.i. as compared to uninfected mice. In contrast, acylcarnitines were initially reduced at 3 d.p.i then elevated after two-weeks of infection, while hydroxysanthine was increased at 14 d.p.i. in infected mice. Our findings suggest that the significant changes in LPCs and other identified metabolites may serve as potential biomarkers in acute phase of B. abortus infection.     

Brucella abortus RB51: enhancing vaccine efficacy and developing multivalent vaccines

Brucella abortus vaccine strain RB51 is an attenuated, stable rough mutant that is being used in many countries to control bovine brucellosis. Our earlier study demonstrated that the protective efficacy of strain RB51 can be significantly enhanced by overexpressing Cu–Zn superoxide dismutase (SOD), a homologous protective antigen. We have also previously demonstrated that strain RB51 can be engineered to express heterologous proteins and mice vaccinated with such recombinant RB51 strains develop a strong Th1 type of immune response to the foreign proteins. The present study is aimed at combining these two characteristics to generate new recombinant RB51 vaccines with enhanced abilities to protect against brucellosis and simultaneously able to protect against infections by Mycobacterium spp. We constructed two recombinant RB51 strains, RB51SOD/85A which overexpresses SOD with simultaneous expression of the 85A, a protective protein of Mycobacterium spp., and RB51ESAT which expresses ESAT-6, another protective protein of M. bovis, as a fusion protein with the signal sequence and few additional amino terminal amino acids of SOD. Mice vaccinated with these recombinant strains developed specific immune responses to the mycobacterial proteins and significantly enhanced protection against Brucella challenge compared to the mice vaccinated with strain RB51 alone.     

中国牛种布鲁菌弱毒疫苗株A19 SNP位点的研究

为鉴别我国牛种布鲁菌弱毒疫苗株A19与野生菌株,运用生物信息学方法结合基因测序,对疫苗株A19基因组SNP位点分析筛选,选取其中部分SNP位点,通过与布鲁菌常见种、生物型标准参考菌株和弱毒疫苗株基因组SNP位置核苷酸测序比较,验证SNP位点的A19特异性。结果表明,共筛选获得A19基因组29个SNP位点,验证ClpX G825-C825、LysR A605-C605、Omp2b G503-A503这3个SNP位点为A19（或S19）特异,揭示了A19基因组SNP位点分布情况,为疫苗株 A19与野生菌株鉴别提供了分子依据。     

改进试管凝集试验法检测布鲁氏菌病抗体

为证实改进的试管凝集试验（SAT）的使用价值,分别用微量试管凝集试验（MSAT）和SAT以国际标准血清为参比检测6份牛布鲁氏菌病阳性血清的抗体效价。结果表明：MSAT和SAT试验结果一致,而且MSAT具有稀释方法更简便、精确,省时省力,可节约血清、抗原等试验原材料,试验结果容易判定,重现性良好等优越性。     

Evaluation of Brucella abortus DNA and RNA vaccines expressing Cu-Zn superoxide dismutase (SOD) gene in cattle

This study was conducted to evaluate the immunogenicity of a DNA or RNA vaccines encoding Brucella abortus Cu–Zn superoxide dismutase (SOD) in cattle. Intramuscular injection of plasmid DNA carrying Brucella SOD gene (pcDNA-SOD) into animals elicited both humoral and cellular immune responses. Animals injected with pcDNA-SOD developed SOD IgG antibody with predominance of immunoglobulin G1 (IgG1) isotype over IgG2. In addition, the DNA vaccine elicited a specific T-cell-proliferative response. Furthermore, intraperitoneal injection of cattle with recombinant Semliki Forest virus particles carrying recombinant RNA encoding SOD (SFV-SOD) did not lead to the induction of SOD IgG 1 or 2 antibody, but induced specific T-cell activation. Both vaccines were able to induce a non-significant secretion of gamma interferon and did not induce the secretion of IL-4 or tumor necrosis factor (TNF)-. These results suggest that SOD gene in a genetic vaccine formulation (DNA or RNA) might be of potential us as a vaccine to induce cell-mediated immunity in cattle. To our knowledge, this is the first study to evaluate a genetic vaccine against Brucella in cattle.