检测肠炎沙门氏菌ELISA方法的建立与应用研究

从已建立的抗沙门氏茵单抗中筛选出适用于肠炎沙门氏菌ELISA检验的3—47—26单抗．采用筛选强阳性杂交瘤细胞株制备了高效价的3—47—26单抗．改进用辣根过氧化物酶标记高效价单抗的方法，进行了HRP标记单抗的免疫生物学特性的鉴定。确定了包被浓度和酶标抗体的工作浓度：HRP-3—47—26为1：100；LPS的包被浓度为400ng／mL。试验中采用LPS与多聚赖氨酸的结合，解决了包被过程中的解吸附作用，增强了包被的稳定性，同时也减少了假阳性反应，优化了包被过程。建立了检测肠炎沙门氏菌的抗原竞争ELISA方法，利用样品中的LPS抑制酶标抗体与包被的LPS结合，以降低底物反应的颜色从而达到检测的目的。通过对210份肠炎沙门氏菌感染鸡泄殖腔棉拭子、羽毛和组织样品先筛选后鉴定的方法进行检测具有明显的抑制作用，通过与国标法对大量的样品检测结果比较表明，竞争ELISA方法的检出率为18．09％；检出阳性样品36份，国标法检出率为17．14％；两者符合率为97．14％。竞争ELISA敏感性和特异性分别为94．4％和97．7‰从而为肠炎沙门氏菌的检测提供了一种敏感、特异的检测方法。     

Development and preliminary application of an indirect ELISA for detecting antibodies against Avian Influenza Virus

Fragment of 759 bp DNA spanning the Matrix 1 (M1) gene of Avian Influenza Virus (AIV) was inserted into an expression vector pET28c to construct a recombinant plasmid pET28c-M1. The pET28c-M1 plasmid was transformed into the Escherichia coli BL21 (DE3) competent cell to produce a recombinant strain E. coli 21 (DE3). After being induced by Isopropyl-b-D-galactopyranoside (IPTG), E. coli 21 (DE3) expressed a 28-kDa fusion protein at a high level. This protein can bind anti-AIV (H5N1) positive serum by Western-blot analysis. After being denatured, renatured, and purified by Ni(2+)-column, the fusion protein was used as an antigen to develop Matrix 1 Enzyme-Linked Immunosorbent Assay (M1-ELISA) for detecting antibodies against AIV from chicken serum. We found that this indirect M1-ELISA was sensitive for differentiating antisera against AIV and antisera against other six kinds of avian viruses apart from AIV and this method is more sensitive than Hemagglutination Inhibition (HI) test. When compared with HI test and ELISA (IDEXX) in evaluating 581 serum samples from field vaccinated chickens, this assay showed 93.3% agreement ratio with the HI test, as well as 96.0% agreement ratio with ELISA (IDEXX). In a preliminary application, the assay successfully detected 19 AIVs from 51 nonvaccinated chicken lungs. It concludes that an indirect ELISA was successfully developed for detecting AIV. The assay is specific and sensitive. The application will greatly contribute to the long-term prevention and control of avian influenza in China.     

Development and validation of an ELISA for detecting antibodies to Eimeria tenella in chickens

The aim of this study was to develop and validate an ELISA for detecting chicken antibodies to Eimeria tenella. An initial comparison of merozoite and sporozoite antigen preparations revealed few differences in their ability to monitor the onset, kinetics and magnitude of the antibody response suggesting that both antigens would be equally useful for development of an ELISA. Furthermore the cross-reactivity of these antigens with sera from birds infected with chicken Eimeria species was similar. The merozoite antigen was selected for further evaluation because it was easier to prepare. Discrimination between sera from birds experimentally infected with E. tenella and birds maintained in an Eimeria-free isolation facility was excellent. In sera collected from free-range layers and commercial broilers there also appeared to be clear discrimination between infected and uninfected birds. The ELISA should prove useful for monitoring infectivity in vaccination programmes in layer and breeder flocks and for assessing the effectiveness of biosecurity measures in broiler flocks.     

鸡白细胞介素18双抗体夹心ELISA检测方法的建立及初步应用

应用识别不同表位的鸡白细胞介素18成熟蛋白(Mature chicken interleukin-18,mChIL-18)的2株单克隆抗体(mAb)1G9和2E6,建立检测mChIL-18的双抗体夹心ELISA,并利用此方法对禽网状内皮组织增生症病毒(Reticuloendotheliosis virus,REV)人工感染SPF鸡体内mChIL-18的分泌水平进行检测。结果显示,捕获抗体的最佳质量浓度为8mg/L,检测抗体的工作效价为1∶800,待检样品的最佳稀释度为1∶400,检测敏感度可达31.5ng/L,与其他细胞因子等抗原蛋白无交叉反应;跟对照组相比,REV感染鸡体内mChIL-18的表达量在7、14、21、28、35、42、49d均呈现升高,但只有14日龄时表现差异显著(P<0.05)。结果表明,本试验成功建立了ChIL-18的双抗体夹心ELISA,为鸡传染病的细胞免疫学研究提供了可靠方法。     

鸡白细胞介素18双抗体夹心ELISA检测方法的建立及初步应用

应用识别不同表位的鸡白细胞介素18成熟蛋白（Mature chicken interleukin-18,mChIL-18）的2株单克隆抗体（mAb）1G9和2E6,建立检测mChlL-18的双抗体夹心ELISA,并利用此方法对禽网状内皮组织增生症病毒（Reticuloendotheliosis virus,REV）人工感染SPF鸡体内mChIL-18的分泌水平进行检测。结果显示,捕获抗体的最佳质量浓度为8mg／L,检测抗体的工作效价为1：800,待检样品的最佳稀释度为1：400,检测敏感度可达31．5ng／L,与其他细胞因子等抗原蛋白无交叉反应;跟对照组相比,REV感染鸡体内mChIL-18的表达量在7、14、21、28、35、42、49d均呈现升高,但只有14日龄时表现差异显著（P〈0．05）。结果表明,本试验成功建立了ChIL-18的双抗体夹心ELISA,为鸡传染病的细胞免疫学研究提供了可靠方法。     

Salmonella enteritidis in chicken eggs

After an outbreak caused by salmonella enteritidis (SE) of which home-made mayonnaise and remoulade sauce were found to be the cause, SE was detected in ten of the remaining eggs. Subsequently 409 eggs of the next shipment from the same outlet were examined bacteriologically. Of 70 of the eggs examined, SE was found in 5 egg yolk samples and in 3 egg white samples as well as in 2 of 7 pooled shell samples. Five out of 35 pooled whole egg samples comprising a total of 349 eggs were likewise positive for SE. The isolates belonged to the phage types 4 and 7 carried the virulence plasmid pRQ29.     

牛传染性鼻气管炎间接ELISA诊断方法的建立

以牛肾细胞系（MDBK）培养牛传染性鼻气管炎病毒（IBRV）Bartha Nu/67株,经超速离心纯化病毒,再经超声破碎处理后作为诊断抗原,建立了检测牛血清IBRV抗体的间接酶联免疫吸附试验.该ELISA的判定标准为：血清D490 nm值大于0.369的判为阳性,小于0.295的判为阴性,在0.295与0.369之间的为可疑.特异性和重复性试验结果表明,该方法特异性高、重复性好.与法国进口ELISA抗体诊断试剂盒比较,其符合率为96.3%;与中和试验比较,符合率为95.8%,且敏感性更高.应用该诊断方法调查了我国部分地区IBRV的感染情况,结果显示,这些地区的IBRV感染率为67.1%.     

Prevalence and persistence of Salmonella in broiler chicken flocks.

Cecal contents of 2,345 broiler chickens consisting of 28 flocks originated from 12 farms were examined for the prevalence of Salmonella to know the actual status of infection with Salmonella in the chicken flocks. Salmonella was isolated from 336 (14.3%) samples. From these isolates, eight serovars were identified. Of the 336 Salmonella isolates, 242 (72.0%) were serotyped as S. Blockley, 60 (17.9%) S. Hadar, 15 (4.5%) S. Bredeney, nine (2.7%) S. Schwarzengrund, four (1.2%) S. Anatum, three (0.9%) S. Enteritidis, two (0.6%) S. Ohio, and one (0.3%) S. Livingstone. The same serovars of Salmonella were repeatedly found in the chickens from the same farms. S. Typhimurium and S. Enteritidis were detected in pooled broken eggshell samples collected from the hatchery. Analysis of plasmid profiles revealed 11 patterns of S. Blockley and seven patterns of S. Hadar. Strains of the same plasmid profiles of S. Blockley were isolated repeatedly from the same farm over one year after the first isolation.     

Salmonella enteritidis and other Salmonella in laying hens and eggs from flocks with Salmonella in their environment.

Seven Canadian layer flocks with Salmonella enteritidis in their environment were investigated to determine the numbers of hens infected with S. enteritidis, the localization of S. enteritidis in organs of infected hens and the numbers of S. enteritidis-infected eggs produced by two affected flocks. By a microagglutination test (MAT) using S. pullorum antigens, these flocks had more seropositive hens (mean 51.9 +/- 16.9%) than two Salmonella-free flocks (mean 13.0 +/- 4.2%). Culture of tissues of 580 hens (433 seropositive) from the seven flocks detected 26 (4.5%) S. enteritidis-infected hens from two flocks. In one flock, 2/150 hens were infected with S. enteritidis phage type (PT) 8, which was confined to the ceca, and no Salmonella spp. were isolated from 2520 eggs (one day's lay). In the second flock, where 24/150 hens were infected with S. enteritidis PT13, extraintestinal infection was found in nine hens and involved the ovaries and/or oviduct in two hens. Salmonella enteritidis PT13 was isolated from one sample of egg contents and from one sample of cracked shells from among 14,040 eggs (one day's lay) from this flock. The overall prevalence of S. enteritidis-contaminated eggs from the two flocks with infected hens was less than 0.06%. Other Salmonella spp. isolated were S. heidelberg from 58 hens (10%), and S. hadar, S. mbandaka and S. typhimurium from one hen (0.2%) each. The MAT with antigens of S. pullorum had a sensitivity of 81% and a specificity of 24% for detecting S. enteritidis-infected hens.(ABSTRACT TRUNCATED AT 250 WORDS)     

Environmental contamination and detection of Salmonella enterica serovar enteritidis in laying flocks.

Faecal, dust and other environmental samples were collected from the floors, droppings belts, egg-collection systems and other areas of 14 cage-layer flocks, 10 barn egg production flocks and seven free-range flocks, and cultured for Salmonella species. The distribution of the organism varied with its prevalence and with the vaccination status of the birds. No one sample type was found to be suitable for identifying all contaminated houses. Salmonella was also frequently found on egg-packing equipment and in samples from rodents and wild birds.     

华支睾吸虫间接ELISA检测方法的建立及初步应用

RT-PCR扩增华支睾吸虫(Clonorchis sinensis)的Enolase基因后,进行原核表达,采用SDS-PAGE和Western blot检测表达产物;以纯化后的蛋白为包被抗原建立ELISA方法,并对工作条件进行优化。结果表明,ELISA最佳工作条件为:抗原最佳包被质量浓度为5mg/L,37℃1h再4℃过夜;5%脱脂奶粉,37℃封闭1h;待检血清1∶100稀释37℃孵育1h;酶标二抗1∶5 000稀释,37℃孵育45min;TMB显色作用时间10min;确定的阴阳性血清临界值为0.253。所建立的ELISA方法特异性较好,可检测犬华支睾吸虫病阳性血清,与犬卫氏并殖吸虫病阳性血清、犬蛔虫病阳性血清、犬弓形虫病阳性血清、犬新孢子虫病阳性血清均不发生反应。该方法敏感性为1∶3 200。批间批内重复性试验变异系数均小于10%。在临床应用中,对浙江地区353多份犬血清的检测表明,样品阳性率为1.13%。本研究建立的间接ELISA方法可以用于临床病例的血清学快速检测,为华支睾吸虫的血清流行病学调查提供了有效手段。     

Plasmid analysis and epidemiology of Salmonella enteritidis infection in three commercial layer flocks.

Ninety-six S. enteritidis isolates obtained from three commercial layer flocks in 1988-90 were examined following DNA extraction, restriction enzyme digestion, and gel electrophoresis for plasmid size profiles and restriction fragment length polymorphisms (RFLPs). The S. enteritidis isolates from the three flocks had three, eight, and two different plasmid profiles, respectively. Only four isolates from one flock lacked plasmids. A 36-megadalton (mDa) (54-kilobase) plasmid was present in 73% of the isolates, either alone or in combination with other plasmids. Isolates with only the 36-mDa plasmid had identical RFLPs. The diversity of plasmid profiles was greater than that of phage-types among isolates from the three flocks: 12 unique plasmid profiles vs. four phage-types. Mixed infections with S. enteritidis strains having distinct plasmid profiles occurred in all three flocks. Reinfection of these flocks in 1990 with one or more of the strains obtained earlier was evident, because some of the original isolates and the 1990 isolates had matching plasmid profiles and were of the same phage-types. Isolates from both environmental and tissue samples, examined from one flock, were found to share the same plasmid profile and phage-type.     

猪巨细胞病毒gB基因的原核表达与间接ELISA检测方法的建立

猪巨细胞病毒(PCMV)是引起新生仔猪死亡、鼻炎、肺炎和生长速度减缓的重要病原之一,我国尚无有效的诊断方法.为建立检测PCMV的ELISA方法,本研究以重组PCMV囊膜糖蛋白B(gB蛋白)为包被抗原,优化反应条件:抗原包被量0.4 μg/mL,待检血清稀释度1∶100,37℃包被2h后4℃过夜,5％脱脂乳37℃封闭2h,二抗1∶10 000稀释,37℃作用2h,抗体临界值为S/P≥0.354判为阳性,S/P≤0.295判为阴性,介于二者之间为可疑,建立了PCMV抗体间接ELISA检测方法.与猪瘟、猪伪狂犬病、猪附红细胞体病、副猪嗜血杆菌及猪圆环病毒2型等血清抗体无交叉反应,批间和批内重复性较好,对江苏省259份仔猪血清样品进行检测,抗体阳性率达56.76％,从而为PCMV检测和流行病学调查提供了有效方法.     

Salmonella typhimurium outbreak in broiler chicken flocks in Mexico

A Salmonella typhimurium outbreak in 1-to-2-week-old broiler flocks in Mexico is reported. Clinical signs were growth retardation, blindness, twisted necks, and lameness. Gross lesions consisted of hypopyon, panophthalmitis, hepatomegaly with necrotic foci, enlarged spleen, pericarditis, coagulated and unabsorbed yolks, and purulent arthritis. Mortality and cull rates in different flocks ranged from 1.7% to 10.6% during the first two weeks of age. All internal organs, eyes, and hock joints of diseased chickens that were cultured were Salmonella-positive. The bacteria were also isolated from the breeder source flock. Disease was thought to be transmitted through eggs at hatch.     

肠炎沙门氏菌灭活苗制作和应用

肠炎沙门氏菌属于无宿主特异性而有侵害性的病原菌之一，宿主包括人和各种动物。该菌不仅能引起家禽发病死亡造成严重的经济损失，而且被污染的家禽产品作为肠炎沙门氏菌的携带者，还严重危害人类健康。据报道，日、美等发达国家发生的食物中毒事件中40％～80％是由禽沙门氏菌引起的，其中主要病原为肠炎沙门氏菌(S G Mellroy，et al．1989)。由肠炎沙门氏菌引起人的急性胃肠炎(食物中毒)，在世界各国有增加的趋势，     

鸡传染性贫血重组抗原间接ELISA诊断方法的建立

本研究应用重组抗原,成功建立了检测鸡传染性贫血病毒血清抗体的间接ELISA诊断方法.确定了抗原最适包被浓度为5μg/mL,血清最适稀释度为1:100,其作用时间为60min,酶标抗体最适作用时间为60min,S/P≥0.24为阳性,≤0.19为阴性,介于二者之间为可疑的判定标准.该抗原不与鸡其他疾病的10种阳性血清反应,具有良好的特异性;批内重复试验,变异系数小于10%,批间重复试验,变异系数小于15%,具有良很好的重复性;该方法可检出人工接毒后20d的血清抗体,直到试验结束110 d时,仍能检出鸡血清阳性率为81%与全病毒包被抗原ELISA方法的检测结果符合率达92%以上,与进口诊断试剂盒的符合率为97%.本研究为现地免疫鸡群抗体检测和进行CIA流行病学调查提供了一种简便的血清学诊断方法.