VP7—ELISA检测牛,羊血清蓝舌病抗体的研究Ⅱ应用VP7—ELISA检 …

蓝舌病ＶＰ７抗原包被板在－２０℃保存期为６个月,４℃保存１个月。抗原批内重复性试验ＣＶ＜１０％,批间重复性试验ＣＶ＜１０％。ＶＰ７－ＥＬＩＳＡ与ＡＧＩＤ对４２０份血清平行检测结果：ＶＰ７－ＥＬＩＳＡ较ＡＧＩＤ试验多检出了１３份阳性样品,ＶＰ７－ＥＬＩＳＡ检出的阳性样品对ＡＧＩＤ阳性样品的覆盖率为９７．４％,对采自陕西等省１８１６份牛、羊血清样品进行检测,检出阳性样品数为２５７份,阳性检出率为１４．     

VP_7-ELISA检测牛、羊血清蓝舌病抗体的研究Ⅱ应用VP_7-ELISA检测蓝舌病抗体

蓝舌病ＶＰ７抗原包被板在－２０℃保存期为６个月,４℃保存１个月。抗原批内重复性试验ＣＶ＜１０％,批间重复性试验ＣＶ＜１０％。ＶＰ７－ＥＬＩＳＡ与ＡＧＩＤ对４２０份血清平行检测结果：ＶＰ７－ＥＬＩＳＡ较ＡＧＩＤ试验多检出了 １３份阳性样品, ＶＰ,－ＥＬＩＳＡ检出的阳性样品对ＡＧＩＤ阳性样品的覆盖率为９７．４％,对采自陕西等省１８１６份牛、羊血清样品进行检测,检出阳性样品数为２５７份阳性检出率为１４．２％。     

山羊实验感染绵羊进行性肺炎病毒的抗体应答反应

用琼脂凝胶免疫扩散试验（ＡＧＩＤＴ）和免疫印迹试验（ＩＢＡ）对山羊实验感染绵羊进行性肺炎病毒（ＯＰＰＶ）的抗体应答反应进行了研究。结果,用ＡＧＩＤＴ和ＩＢＡ都可在接毒山羊的血清中检测到ＯＰＰＶ的抗体。ＡＧＩＤＴ最早于接毒后１５ｄ检测到抗体;ＩＢＡ最早于接毒后４ｄ检测到抗ＯＰＰＶ的ｇｐ４４和ｐ２８的抗体,以后又陆续检测到抗ｐ９４、ｐ１４和ｇｐ１２５的抗体。由此看出,ＩＢＡ比ＡＧＩＤＴ更为敏感。本研究结果表明,ＯＰ－ＰＶ可在山羊体内诱生较强的体液免疫应答反应,因此用ＯＰＰＶ通过山羊体传代的方法可能会得到具有良好抗原性的ＯＰＰＶ毒株。     

应用C—ELISA检测禽流感病毒核蛋白抗体

应用杆状病毒表达的重组核蛋白及单抗建立了竞争ＥＬＩＳＡ（Ｃ—ＥＬＩＳＡ）,用于抗Ａ型禽流感病毒核蛋白抗体的检测。试验检测了７５６只鸡,１１２３只火鸡,７０７只鸸鹋和１２６１只鸵鸟的共３８４７个血清样品。与琼脂扩散试验（ＡＧＩＤ）对比,Ｃ—ＥＬＩＳＡ方法对上述四种血样的敏感性均为１００％;而与血凝抑制试验（ＨＩ）相比,则其敏感性在鸡、火鸡和鸸鹋为１００％。鸵鸟为９６．２％。经ＡＧＩＤ检测为阴性而Ｃ—ＥＬＩＳＡ阳性的样品中有９０％以上通过ＨＩ试验至少一种血清亚型呈阳性反应。试验发现Ｃ—ＥＬＩＳＡ和ＡＧＩＤ方法的特异符合率在８５．５％—９９．８％之间。这些结果表明,Ｃ—ＥＬＩＳＡ和ＨＩ一样都比ＡＧＩＤ更敏感、更特异。因此,Ｃ—ＩＬＩＳＡ有可能取代ＡＧＩＤ,用于禽类（包括平胸鸟）Ａ型流感病毒血清学监测。     

应用琼脂免疫扩散试验检测猪伪狂犬病抗体的研究

建立了ＡＧＩＤ用于猪伪狂犬病（Ｐｓｅｕｄｏｒａｂｉｅｓ,Ｐｒ）的诊断。对９８份被俭血清的ＡＧＩＤ结果与ＳＮ结果比较,当ＳＮ滴度大于１：８时两者的阳性检出符合率为１００％,ＳＮ滴度小于或等于１：８时,两者的阳性检出符合率为８７．５％,ＡＧＩＤ和ＳＮ总的阳性符合率为９４．４％,结果表明,ＡＧＩＤ对Ｐｒ可进行特异性诊断,流行病学调查和免疫动态监测。     

用固定细胞阻断酶联免疫吸附试验鉴别诊断猪传染性胃肠炎病毒和猪呼吸道冠状病毒的感染

用固定细胞阻断酶联免疫吸附试验（ＥＬＩＳＡ）对来自丹麦猪的１８０份血清进行了猪传染性胃肠炎病毒（ＴＧＥＶ）和猪呼吸道冠状病毒（ＰＲＣＶ）感染的鉴别诊断，共检出了ＰＲＣＶ抗体阳性血清１０７份（５９．４％），ＴＧＥＶ抗体阳性血清０份。同时也检测了一些来自国内不同ＴＧＥＶ感染类型的猪场血清。该鉴别诊断方法在我国的建立和应用为从ＰＲＣＶ阳性国家进口猪的ＴＧＥ的检疫提供了一条有效途径。     

赤羽病间接ELISA检测方法的建立和标化

应用赤羽病病毒(AKV)OBE-1株和牛标准阴阳性血清，以蔗糖密度梯度离心纯化细胞毒为包被抗原，在国内首次建立了检测AKV抗体的间接ELISA方法。该方法与中和试验相关系数0．7614，特异性和重复性良好。应用此方法对南京、上海附近奶牛抽样检测，阳性率分别为26．7％和32．7％。对澳大利亚、加拿大、美国进口牛13600头份进行检测，全部阴性。     

牛赤羽病胶体金抗体检测试纸条的研制

研究旨在制备一种现场快速筛查牛赤羽病的免疫层析试纸条。通过胶体金标记赤羽病病毒N蛋白,将兔抗牛IgG和兔抗N蛋白多克隆抗体分别喷涂于NC膜上作为检测线（T）和质控线（C）。结果显示,牛赤羽病毒阳性抗体血清稀释度为1∶512时,检测线仍显色;且与牛病毒性腹泻病毒、牛结核病、布鲁氏菌病、牛巴氏杆菌病、地方流行性牛白血病毒和蓝舌病毒的阳性血清均无交叉反应;使用试纸条和商品化ELISA试剂盒同时检测40份田间牛血清样品的结果符合率为92.6%。研究表明,试纸条适用于基层养殖户对牛赤羽病的筛查。     

建立一种牛血清IgG检测的自动比浊免疫分析法

建立一种自动比浊免疫分析法（ＴＩＡ）用于牛ＩｇＧ的检测。２４头份牛血清样品的ＩｇＧ浓度通过ＴＩＡ法测定，结果与放射免疫扩散法（ＲＩＤ）比较：ＴＩＡ法与ＲＩＤ法之间有显著的正向相关性（γ＝０９９５７，Ｐ＜００５），直线回归方程斜率为０７８７０８，Ｙ轴截距为１０２１０２。ＴＩＡ法用于牛血清ＩｇＧ定量检测是自动、快速和高精度的，溶血对ＩｇＧ测量结果无影响。临床应用：ＴＩＡ法可在约１０分钟内提供样品结果，因此可用于替代手工操作ＲＩＤ法。     

禽血清网状内皮组织增殖病毒抗体的检测

采集日本不同地区的鸡和其它禽类的血清检测网状内皮组织增殖病毒抗体琼脂凝胶免疫扩散试验的结果为：５４个鸡场中的２５．９％、１２６个鸡群中的２１．４％、１８９２只鸡中的１４．３％为阴性，所有ＡＧＩＤ阳性血清在间接免疫荧光或病毒中和试验中也为阳性，其它禽血清ＡＧＩＤ试验阳性结果为，北京鸭（１／１２０）和雉鸡（４／２７）。     

Comparison of four serologic tests for the detection of antibodies to bovine leukemia virus

Four tests for detection of antibodies to bovine leukemia virus (BLV) were compared. The sera that were tested came from cattle in naturally infected commercial dairy herds, cattle that were infected under experimental conditions, and cattle in an isolated BLV-free herd. The tests that were compared included a radioimmunoprecipitation assay (RIA) with p24 antigen, a RIA with glycoprotein (gp) antigen, an agar-gel immunodiffusion (AGID) test with gp antigen, and a virus-neutralization (VN) test that was based on inhibition of BLV-induced syncytia in cell culture. Results of the 4 serologic tests agreed for 96.8% of the sera from cattle in commercial herds. The gp RIA detected the greatest number of positive sera (188); it was followed in turn by the p24 RIA (187), the VN test (183), and the AGID test (176). The gpd RIA titers of the 12 sera that gave negative AGID results were 175 or less. In RIA, the percentage of precipitation of labeled antigen by positive sera was almost always higher with gp antigen than with p24 antigen. Satisfactory sensitivity in the p24 RIA required the acceptance of a low level of antigen precipitation, 15%, as a positive test. In the gp RIA, however, almost all positive sera precipitated at least 50% of the labeled antigen. Nonspecific precipitation of antigen in the RIA by sera from BLV-free cattle ranged from 4% to 10%. Examination of sequential serum samples from 17 experimentally infected cattle showed that BLV antibody was first detected 2 to 8 weeks after inoculation. In 9 cattle, seroconversion was detected simultaneously by all of the tests. Results from the other 8 cattle indicated that seroconversion could be detected first by p24 RIA, followed by the gp RIA and the VN test. The longest interval between RIA seroconversion and AGID seroconversion was 10 days. Monthly tests of sera from 10 laboratory cattle that were infected by contact exposure showed that 7 animals seroconverted in all tests at the same time. Two cattle were positive first in RIA, but the next month they were also positive in the VN and AGID tests. One animal was positive in the RIA and the VN test for 2 months before antibody was detected by AGID.     

Comparison of the agar gel immunodiffusion test and ELISA in the detection of bovine leukosis virus antibody in cattle persistently infected with bovine virus diarrhoea virus

When six cattle persistently infected with bovine virus diarrhoea virus (BVDV) were inoculated with lymphocytes infected with bovine leukosis virus (BLV), a depressed antibody response to BLV was observed by ELISA which was due to a decrease in IgG1 synthesis. The ELISA was more sensitive and more reliable than the agar gel immunodiffusion (AGID) test in detecting BLV infection in cattle persistently infected with BVDV. Decreased antibody responses were manifested in the AGID test by negative, inconclusive or weakly positive reactions: only two of the six cattle developed antibodies that generated positive AGID reactions.     

Development and evaluation of an enzyme-linked immunosorbent assay for detection of bovine antibodies to epizootic hemorrhagic disease of deer viruses.

An indirect enzyme-linked immunosorbent assay (I.ELISA) is described for detection of bovine serum antibody to epizootic hemorrhagic diseases of deer virus (EHDV). Serum samples, at a dilution of 1:200, were incubated with group-specific EHDV antigens, pre-adsorbed to microtiter plates. Bound antibodies were detected by a murine monoclonal antibody to bovine immunoglobulin (Ig)G1 (heavy-chain specific) conjugated with horseradish peroxidase. The performance of the I.ELISA in detecting antibodies to EHDV in sequential serum samples from calves experimentally infected with serotypes 1,2,3 and 4 was evaluated. The I.ELISA detected EHDV antibodies from 14 days postinfection when seroconversion by the standard agar gel immunodiffusion (AGID) test was also evident. The group-specific antibodies to EHDV increased exponentially during the first two to four weeks postinfection and remained relatively stable for about 12 months in some calves. Unlike observations with the AGID test, no reaction was seen in the I.ELISA between blue-tongue virus (BTV) antigen and sera from calves given a single dose of EHDV. The performance of the I.ELISA and AGID were compared using 3,135 AGID negative bovine field sera from herds in Ontario, Alberta and British Columbia and 130 AGID positive samples collected from cattle in 1987 and 1988 during and after outbreaks of EHD in the Okanagan Valley, British Columbia. The specificity and sensitivity of the assay relative to the AGID test were 99.3% and 91.5% respectively, with an overall agreement of 99.0% between the tests.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of the complement-fixation and agar gel immunodiffusion tests for diagnosis of subclinical bovine paratuberculosis

The performance of the serum complement fixation (CF) test was compared with that of a serum agar gel immunodiffusion (AGID) test on 74 subclinically infected and 154 uninfected cattle in 6 commercial midwestern dairy herds with Mycobacterium paratuberculosis infection and on 30 cattle in a herd that was free of infection. Infection status of cattle within herds was established by performance of a series of 3 or more fecal cultures and of ileocecal lymph node cultures of culled cattle. In cattle with subclinical infection detected by culturing, the sensitivity estimates of the CF and AGID tests were 10.8% (3.6% SE) and 18.9% (4.5% SE), respectively. In the cattle classified as disease free, the specificity estimates of the CF and AGID tests were 97.4% (1.3% SE) and 99.4% (0.6% SE), respectively. Neither set of estimates was significantly different. Negative test results obtained with the use of either test in apparently normal cattle from suspect herds should be interpreted with caution because both tests suffer from low sensitivities in subclinically infected animals. However, the AGID test may be more useful in regulatory situations in which the CF test is currently used because the AGID test is easier to perform and to interpret.     

Serologic and virologic investigations on the presence of BLV infection in a dairy herd in Syria

237 cattle of a dairy herd in Syria were tested for anti-BLV antibody by the ELISA. 194 animals were additionally examined by the agar gel immunodiffusions test (AGID) on BLV antibodies and 100 by polymerase chain reaction (PCR) for BLV provirus. BLV specific antibodies were determined by means of AGID and ELISA at 62.9% and 69.2% of the examined animals, respectively. Using the PCR method the BLV provirus was detected in 89% of the investigated cattle. Only one ELISA seropositive animal was negative for BLV provirus. The results show the high BLV contamination of this herd and lead to the presumption of wide spread enzootic bovine leukosis in Syria. In the case of the diagnosis of BLV-infection, the PCR-technique compared to the serological tests proved to be much more sensitive. By the detection of BLV antibody, the ELISA showed a higher sensitivity than the AGID and in this way, is advisable as a method of choice for screening investigations. Restriction enzyme and sequence analysis of PCR-amplificates demonstrate that different BLV provirus variants (A, B and C) in the examined herd occur, where the variant C which a high similarity to an Australian BLV provirus isolates showed, occurred most frequently at 92.5%.     

Comparison of competitive ELISA, indirect ELISA and standard AGID tests for detecting blue-tongue virus antibodies in cattle and sheep

The performances of a competitive enzyme-linked immunosorbent assay (ELISA) using a group specific monoclonal antibody against bluetongue virus, an indirect ELISA and the standard agar gel immunodiffusion (AGID) test were compared in the detection of serum antibody against bluetongue virus. Test sera consisted of 1300 bovine, 530 ovine and 160 carpine samples from bluetongue-free areas of Canada, 605 bovine and ovine field samples from the USA and Barbados and 464 samples from 79 cattle and sheep experimentally infected with 19 South African and five USA serotypes of bluetongue virus. The diagnostic specificity of the competitive ELISA, as determined for the bluetongue virus-free cattle sera was superior (99.92 per cent) to that of the indirect ELISA (99.85 per cent) and the AGID (99.0 per cent). The specificities of the competitive ELISA for sheep (99.63 per cent) and goats (100.0 per cent) sera were also higher than those of the AGID test. The performance of the ELISA tests was similar whether a gamma-ray-irradiated (2.0 Mrad) or a non-irradiated bluetongue virus antigen preparation was used. The competitive ELISA results for bovine field sera from endemic areas demonstrated a relatively low level of agreement (92.04 per cent) with AGID test results, with 9.7 per cent false negatives. The possible presence in these sera of antibody to cross-reacting antigens or to other orbiviruses, eg, epizootic haemorrhagic disease virus, which react in the AGID but not in the competitive ELISA may account for this lack of agreement.(ABSTRACT TRUNCATED AT 250 WORDS)     

Agar gel immunodiffusion test for diagnosis of clinical paratuberculosis in cattle

During a 19-month period, the agar gel immunodiffusion (AGID) test was used as an aid in differential diagnosis of paratuberculosis in 51 cattle with a history of chronic weight loss and/or chronic diarrhea. Thirty-three cattle were AGID test-positive for paratuberculosis. Twenty-eight cattle (87.5%) yielded Mycobacterium paratuberculosis from bacterial culture of feces. Four cattle were confirmed as having paratuberculosis on necropsy. One had a negative fecal culture but was lost to follow-up. Thus, 32 of the 33 AGID test-positive cattle (96.9%) were confirmed as paratuberculous by culture or necropsy. Of the 18 cattle that were AGID test-negative, 17 (94%) also were culture-negative after 12 to 20 weeks' incubation of the culture tubes. Direct fecal smears from 29 confirmed paratuberculous cattle were examined. Twenty-three (79.3%) had smears positive for M paratuberculosis. Fifteen culture-negative cattle were examined by direct smear; the results were negative for all.     

Evaluation of the agar gel immunodiffusion test for diagnosis of subclinical paratuberculosis in cattle

Concurrent bacteriologic culture of feces and agar gel immunodiffusion (AGID) testing was performed on all cows and bred heifers over 14 months old in 10 dairy herds during a 32-month period to determine the effectiveness of the AGID test for the detection of subclinical paratuberculosis. Herds were sampled 5 times and, when possible, culled animals were tested again at slaughter. During 5 herd-wide samplings, Mycobacterium paratuberculosis was isolated from 139 fecal specimens obtained from 109 cattle. Results of the AGID test were simultaneously positive 40 of 139 times (28.8%). Thirty-six of the 109 cattle (33.0%) determined to be infected had a positive AGID test result at some point during the 5 herd-wide samplings. When results of tests performed at time of slaughter were included, 117 cattle were identified as infected by culture methods; 55 of these (47.0%) were AGID test-positive at some point during the study. The upper limit of the maximal false-positive rate for the AGID test was 2.1%. On the basis of colony counts from cultures, subclinically infected cows shedding higher numbers of M paratuberculosis in their feces were more likely to have positive AGID test results (P less than 0.0001). In known infected cattle, neither the culture nor AGID test results were consistently positive on repeated testing. Of 48 official calfhood paratuberculosis vaccinates tested as adults, 3 had positive AGID test results and in 1 of these, M paratuberculosis was also isolated from the feces, indicating that the rate of false-positive AGID test results in calfhood vaccinates is low.     

Specificity of absorbed ELISA and agar gel immuno-diffusion tests for paratuberculosis in goats with observations about use of these tests in infected goats

OBJECTIVE: To determine the specificity of serological tests that are currently used in veterinary diagnostic laboratories in Australia for detection of Mycobacterium avium subsp paratuberculosis infection in goats. DESIGN: A laboratory study. PROCEDURE: Four tests were studied, comprising AGID with M. a. paratuberculosis antigen derived from cattle isolates of caprine or bovine origin, the EMAI caprine Johne's disease absorbed ELISA and the CSL PARACHEK Johne's absorbed EIA. The specificities of AGID and ELISA for paratuberculosis (Johne's disease) were estimated after examining a panel of 1000 serum samples collected from goats in Western Australia, a region free of paratuberculosis. In addition a comparison was made of test performance in a small number of paratuberculous goats from New South Wales using sera from two archival collections. RESULTS: The specificity of the AGID tests was 100% while the specificities of the two absorbed ELISA were 99.7 to 99.8% at appropriate positive-negative cut-offs. Based on testing the small sample of sera from infected goats, the absorbed ELISA tests detected about twice as many goats with Johne's disease as the AGID. Each test detected paratuberculous animals regardless of whether infection was caused by cattle or sheep strains of M. a. paratuberculosis. CONCLUSIONS: Both ELISA and AGID tests for paratuberculosis have high specificity and can be used in a market assurance program without risk of generating large proportions of false positive test results. However, the results suggested the ELISA is more sensitive for detection of infected goats and should be used in preference to the AGID. The two formats of ELISA evaluated in this study have similar characteristics and could be used in paratuberculosis control programs for the goat industries, but further data on sensitivity would increase confidence in their application.     

An enzyme-linked immunosorbent assay for detection of antibodies to maedi-visna virus in sheep. II. Comparison to conventional agar gel immunodiffusion test.

A study was conducted to compare the indirect enzyme-linked immunosorbent-assay (i-ELISA) test using antigen prepared by a simple technique using sodium dodecyl sulfate (SDS) treatment to the conventional agar gel immunodiffusion test (AGID). Ten specific-pathogen-free (SPF) sheep were inoculated with maedi-visna virus (MVV) and serum antibody titers compared over a period of 14 weeks. All the sheep seroconverted by the i-ELISA compared to 90% by the AGID. The i-ELISA detected antibody at a mean of 2.6 weeks prior to the AGID. In both tests, fluctuations were observed in the serum antibody response of two sheep. The i-ELISA had a specificity of at least 98.8% and an increased relative sensitivity of 15.5% compared to the AGID, based on the analysis of sera from experimental sheep with MVV free status and sera from sheep from various sources. Of the sera from a seronegative flock which had been monitored with the AGID after a "test and remove" eradication program, 10.2% were positive by the i-ELISA. It was concluded that the AGID test may not be adequate to monitor samples for an eradication scheme.