间接Dot—ELISA检测猪细小病毒抗原的研究

本文成功地建立了间接斑点酶联免疫吸附试验（Ｄｏｔ－ＥＬＩＳＡ）用于检测ＰＰＶ抗原体对纯化ＰＰＶ抗原的最低检出量为２．５ｎｇ／点。ＰＰＶ阳性猪血清的特异性阻断试验及交叉反应试验证明，该方法对ＰＰＶ抗原的检测具有特异性。以该方法检测ＰＰＶ人工感染兔样本和自然染猪样本，ＰＰＶ抗原的阳性检出率分别为肾样本１００％（１７／１７）、８１．８２％（９／１１），肝样本１００％（１６／１６）、５６．５２％（１３／２     

银加强胶体金技术检测猪细小病毒的研究

本研究首次成功地建立了检测猪细小病毒（ＰＰＶ）抗原的银加强胶体金检测法（ＳＥＣＧＡ），并确定了操作流程中的最佳试验条件。应用该法对纯化ＰＰＶ抗原的最低检出量为０．３１２５ｎｇ／点，其敏感性分别为间接Ｄｏｔ－ＥＬＩＳＡ和ＨＡ的８倍和１０００倍。特异性阻断试验和交叉反应试验证明ＳＥＣＧＡ具有较高的特异性。２０份样本ＳＥＣＧＡ的检测结果与病毒分离和鉴定结果完全相符。ＳＥＣＧＡ和间接Ｄｏｔ－ＥＬＩＳＡ对７７份样本检测的阳性率分别为８３．１％和８０．５％，其阳性符合率为９６．９％。研究结果表明本法具有经济、敏感性、特异性强等优点，可用于ＰＰＶ感染的特异诊断。为胶体金技术应用于畜禽传染病的诊断和研究奠定基础。     

斑点酶联免疫吸附试验检测猪繁殖与呼吸综合征病毒抗体方法的建立

首次建立了斑点－酶联免疫吸附试验（Ｄｏｔ－ＥＬＩＳＡ）检测猪繁殖与呼吸综合征病毒（ＰＲＲＳＶ，美洲株）抗体的方法。特异性鉴定表明，ＰＲＲＳＶ不与猪瘟病毒、猪伪狂犬病病毒、猪细小病毒阳性血清反应；与美国进口的ＰＲＲＳＶ抗体ＥＬＩＳＡ诊断试验盒检测结果比较，３５份猪血清的阴、阳性检出总符合率为８２．９％（２９／３５），其中Ｄｏｔ－ＥＬＩＳＡ的阳性检出率略高于进口试剂盒的检出率。     

斑点酶联免疫吸附试验检测牛羊捻转血矛线虫病的研究

应用斑点酶联免疫吸附试验（Ｄｏｔ－ＥＬＩＳＡ）检测牛羊捻转血矛线虫病抗体，经对３９头剖检羊血纸检测，结果表明该法与剖检法的阳性符合率达１００％（２７／２７），阴性符合率也达１００％（１２／１２）。Ｄｏｔ＝ＥＬＩＳＡ能检出第四胃寄生１＝３３８条捻转血矛线虫羊的血清或血纸抗体；应用Ｄｏｔ－ＥＬＩＳＡ对５９９份牛、羊血纸的测定结果，与粪检地的阳性符合率达９５．５８％，阴性符合率达９１．４３％。初步认为Ｄ     

斑点免疫金银染色法检测鸡传染性支气管炎病毒抗原的研究

用建立的斑点免疫金银染色（Ｄｏｔ－ＩＧＳＳ）法检测鸡传染性支气管炎病毒（ＩＢＶ）抗原,确定兔抗ＩＢＶ血清工作浓度为１：４００,ＳＰＡ－胶体金探针的工作浓度为１：８０,该法对纯化ＩＢＶ抗原的最低检出量为０．４３１４ｎｇ／点,用Ｄｏｔ－ＩＧＳＳ与斑点酶联免疫吸附试验（Ｄｏｔ－ＥＬＩＳＡ）同时检测１５只人工感染ＩＢＶ鸡的气管,肺,肾病科,ＩＢＶ阳性检出率均为１００％,对３２份疑似ＩＢＶ感染鸡病料检测,Ｉ     

间接法Dot－ELISA检测鸡败血支原体（MG）抗原的研究

本文首次建立了检测鸡败血支原体（ＭＧ）抗原的间接法Ｄｏｔ－ＥＬＩＳＡ。ＭＧ抗原的最低检出量为７．８１×１０￣４ＣＦＵ／ｍｌＭＧ人工及自然感染样本的抗原检测结果与ＭＧ分离的符合率分别为８４．６％和９２．９％。间接法Ｄｏｔ－ＥＬＩＳＡ检测抗原经济、快速、操作简便，有较好的敏感性、特异性和重复性，能检出ＭＧ人工及自然感染病鸡的带菌情况，适合于大规模抗原样本的检测，可以用作疫病早期诊断的依据和进行流行病学调查。     

单抗介导的斑点ELISA检测鸡传染性支气管炎病毒的研究

用群特异性的单克隆抗体作第一抗体,用酶标兔抗体ＩＢＶＩｇＧ作第二抗体,建立夹心法Ｄｏｔ－ＥＬＩＳＡ程序检测鸡传染性支气管炎病毒抗原。试验表明,本程序检测ＩＢＶ抗原高度敏感性和特异性。最低抗原检出量为０．５μｇ,约１００个气管环半数感染量（１００ＴＯＣＩＤ５０）,阳性检出率为９６％。     

间接法Dot－ELISA检测副鸡嗜血杆菌的研究

本文首次成功地建立了检测副鸡嗜血杆菌（ｈｐｇ）抗原的间接法Ｄｏｔ－ＥＬＩＳＡ。Ｈｐｇ抗原的最低检出量为３．９１×１０￣５ＣＦＵ／ｍｌ。Ｈｐｇ人工感染样本的抗原阳性检出率为：口咽试子９５．５％；鼻窦及眶下分泌物拭子９０．９％。经统计学分析，二者在５％显著水平无显著差异。人工感染后４天及８天口咽拭子的抗原阳性检出率分别为１００％和９５．５％。经统计学分析，二者在５％显著水平无显著差异。Ｈｐｇ自然感染样本的抗原检出率为：口咽拭子８１．７％，鼻分泌物拭子７７．８％，眶下窦分泌物拭子７６．９％。间接法Ｄｏｔ－ＥＬＩＳＡ检测抗原经济、快速、操作简便，有较好的敏感性、特异性和重复性，能有效检出Ｈｐｇ人工及自然感染病鸡的带菌菌况，适合于大规模抗原样本的检测，可以用作疫病早期诊断和进行流行病学调查。     

ELISAA法检测犬腹泻粪样中的犬冠状病毒

用ＦＥ细胞增殖犬冠状病毒（ＣＣＶ）参考株，分别免疫家兔和ＢＡＬＢ／ｃ小鼠制备ＣＣＶ多抗和单抗，建立了夹心ＥＬＩＳＡ及Ｄｏｔ－ＥＬＩＳＡ诊断方法。在检测的８４例犬腹泻粪样中，多抗、单抗夹心法显示ＣＣＶ阳性１６例，Ｄｏｔ－ＥＬＩＳＡ阳性１３便，后１３例包括在前１６例中，从８４例腹泻犬粪样中随机取３例作ＣＣＶ、犬细小病毒（ＣＰＶ）双项检测，ＣＣＶ阳性１６例，ＣＰＶ阳性６例，ＣＣＶ、ＣＰＶ混合感染４例。结     

Dot—ELISA检测猪生殖和呼吸综合征抗体的研究

用差速离心法提纯ＰＲＲＳ病毒，利用ＮＣ膜作为载体，在国内外首次成功建立了检测ＰＲＲＳ血清抗体的斑点酶联免疫吸附试验（Ｄｏｔ－ＥＬＩＳＡ）。抗原包被浓度为１００μｇ／ｍｌ，被检血清工作浓度为１：１０，酶标兔抗猪ＩｇＧ工作浓度为１：６００。对７２份北京地区猪血清分别用Ｄｏｔ－ＥＬＩＳＡ和ＩＦ检测，Ｄｏｔ－ＥＬＩＳＡ检测阳性率为３３．３％，ＩＦ检测阳履率为３０．６％，与ＩＦ符合率较高，对部分待检血清检测     

Comparison of Dot-ELISA, ELISA and IFAT for the detection of IgG antibodies to Sarcocystis muris in experimentally infected and immunized mice

The dot enzyme-linked immunosorbent assay (Dot-ELISA) was used for the detection of IgG antibodies to Sarcocystis muris and compared with the enzyme-linked immunosorbent assay (ELISA) and the indirect fluorescent antibody test (IFAT). In experimentally infected mice, first positive reactions occurred in the Dot-ELISA between 18 and 32 days after infection (dpi), in the ELISA between 18 and 49 dpi, and in the IFAT between 11 and 25 dpi. Maximum titers were 1:40 960 in the Dot-ELISA, 1:1280 in the ELISA and 1:2560 in the IFAT. High titers persisted until the end of the examination period (182 dpi) in all 3 tests. In immunized mice, all 3 tests detected antibodies 7 days after the first injection of protein antigen. The highest titers of 1:5120 and 1:10 240 were recorded in the Dot-ELISA after 35 days; titers of 1:1280 and 1:2560 were observed in the ELISA, and titers of 1:160 and 1:320 in the IFAT after 42 days. No false-positive reactions occurred in the Dot-ELISA and in the IFAT when 177 sera from non-infected mice were examined, but 1% (2/177) of the sera reacted positively in the ELISA. Sixty-three percent (94/150) of sera from mice infected experimentally with Toxoplasma gondii showed slight positive reactions up to 1:40 in the Dot-ELISA; 9% (13/150) of the sera reacted positively up to 1:40 in the IFAT and 4% (6/150) up to 1:20 in the ELISA. The Dot-ELISA appears to be a good alternative to the ELISA and the IFAT in the serodiagnosis of sarcosporidiosis and should be further evaluated for the serodiagnosis of other parasitic diseases.     

Identification of viral pathogens in aborted fetuses and stillborn piglets from cases of swine reproductive failure in Spain

The objective of the present study was to determine the presence of recognised abortifacient viruses such as porcine reproductive and respiratory virus (PRRSV), Aujeszky's disease virus (ADV), porcine parvovirus (PPV) and porcine circovirus type 2 (PCV2), in tissues from aborted fetuses and stillborn neonates in cases of late reproductive failure in swine. A total of 293 specimens (fetuses aborted in the last third of gestation and stillborn piglets) from 100 different cases of late-term abortions and premature farrowing from 15 different Spanish provinces were studied. PRRSV was detected in 9/100 cases by RT-PCR. Only 1/100 cases analysed (corresponding to a late-term aborted fetus with a negative PRRSV RT-PCR result) was positive for PCV2 by PCR. Neither ADV (monitored by viral isolation plus antigen detection) nor PPV (monitored by ELISA antigen capture test) infection was identified. The results suggest that PRRSV is one of the most important infectious agents, if not the most relevant one, associated with fetal infection leading to abortion or premature farrowing in Spain. Moreover, other viral pathogens such as ADV, PPV and PCV2 seem to have a minor impact on reproductive disease.     

Occurrence of Toxoplasma gondii antibodies in Dasyprocta aguti from Brazil: comparison of diagnostic techniques

In this study, the occurrence of antibodies to Toxoplasma gondii in Brazilian agouti (Dasyprocta aguti) was compared by modified agglutination test (MAT) and indirect fluorescent antibody test (IFAT) using anti-capybara conjugate. Sera from 109 animals were tested using MAT (1:25 cut-off) and IFAT (1:16 cut-off); 19% were positive by MAT, and 18% were positive by IFAT. Overall, the 17 IFAT-positive samples were also positive for MAT. The four positive MAT samples with a titer < or = 200 were IFAT negative. All negative samples obtained by MAT matched with the results of the IFAT. Comparing both tests, and considering MAT as the gold standard, the sensitivity of IFAT was 81%, the specificity was 100%, the accuracy was 97%, the positive predictive value (PPV) was 100%, and the negative predictive value 96%. The kappa value agreement was 87.3% (75.1-99.6%). The anti-capybara conjugate can be successfully used to perform IFAT in Brazilian agouti with maximum specificity and PPV.     

A current assessment of the role of porcine parvovirus as a cause of fetal porcine death.

One hundred one litters containing 1 or more dead porcine fetuses were collected at an Iowa abattoir during a 2-month interval and examined for evidence of viral infection. Each of 1,137 fetuses (302 dead, 835 alive) of these litters was tested for porcine parvovirus (PPV) antigens by direct immunofluorescence microscopy (FA) of fetal lung. Antigens of PPV were detected in the lungs of most of the fetuses of 11 of the litters. The 11 FA-positive litters contained 105 dead (100 FA-positive) and 14 live (12 FA-positive) fetuses. Infectious PPV was isolated from 10 of the 11 FA-positive litters and from 3 of the 90 FA-negative litters. No cytopathogenic agents other than PPV were isolated from any of the litters. Eleven of 101 (11%) litters examined and 100 of 302 (33%) dead fetuses examined were FA positive for viral antigen, indicating that PPV remains as a major cause of porcine fetal death.     

Detection of Campylobacter antibodies in sheep sera by a Dot-ELISA using acid extracts from c. fetus ssp. fetus and c. jejuni strains and comparison with a complement fixation test

In this study, a dot-enzyme-linked immunosorbent assay (Dot-ELISA) was evaluated in comparison with a complement fixation test (CFT) for the detection of Campylobacter antibodies in sheep sera. Acid glycine extracts (AGE) of both Campylobacter fetus ssp. fetus and Campylobacter jejuni strains that had been isolated from the gall-bladder of slaughtered sheep was used as antigen in both tests. A total of 153 sheep sera from aborted (74) and slaughtered (79) sheep were examined by both Dot-ELISA and CFT. Twenty-two sera showed anti-complementary activity were not suitable for CFT. Of the 22 sera showing anti-complementary activity, two sera were found to be positive in Dot-ELISA. Eighty-eight (67.2%) of the remaining 131 sera were negative by both Dot-ELISA and CFT using AGE of both Campylobacter strains whereas 43 sera (32.8%) gave different reaction patterns in Dot-ELISA and CFT with the extracts of both Campylobacter strains. Twelve sera were positive by both tests using AGE of C. fetus ssp. fetus but CFT failed to detect antibodies in nine of these sera when AGE of C. jejuni was used. Twelve sera were positive by both tests only when AGE of C. fetus ssp. fetus was used. Eleven sera were positive only by CFT. Seven of these reacted only with the AGE of C. fetus ssp. fetus and four sera were positive by using AGE of both Campylobacter strains. The remaining eight sera were found to be positive only by dot-immunobinding assay either with the AGE of both Campylobacter strains or with the AGE of one of the Campylobacter strains. It is concluded that Dot-ELISA using AGE from C. fetus ssp. fetus could be employed for the detection of Campylobacter antibodies in sheep sera and the additional use of AGE from C. jejuni as antigen appeared not to be profitable for this purpose.     

基于重组NS1蛋白猪细小病毒野毒抗体间接ELISA诊断方法的建立与应用

本研究以原核表达的重组NS1蛋白作为诊断抗原,建立了检测猪细小病毒(PPV)野毒抗体的NS1-ELISA诊断方法。该方法检测猪瘟病毒、猪繁殖与呼吸综合征病毒、猪伪狂犬病病毒、猪圆环病毒2型、猪流行性腹泻病毒5种常见猪病病毒的阳性血清均为阴性;检测灵敏度为1:12800;批内、批间重复性试验的变异系数分别小于5%和10%;与血凝抑制试验(HI)符合率为100%。本研究建立的PPV NS1-ELISA检测方法具有良好的特异性、敏感性和重复性,为PPV的野毒抗体检测及PPV流行病学调查等快速诊断提供了一种技术手段。     

基于非洲猪瘟病毒p30与p54蛋白表位串联多肽的间接ELISA抗体检测方法的建立

旨在建立检测非洲猪瘟病毒(ASFV)血清抗体的间接ELISA方法。本研究以两株纯化的ASFV p30与p54蛋白单克隆抗体(mAbs)为靶分子,利用噬菌体展示十二肽库进行四轮生物淘选,筛选多肽表位,以氨基酸GGG为接头设计合成表位串联多肽作为包被抗原,通过棋盘滴定法确定间接ELISA的最佳反应条件,利用不同类型血清样本对建立的方法进行特异性分析、敏感度分析、稳定性分析及符合性评价。噬菌体淘选试验结果表明¹⁴⁶PAEPYTT¹⁵²为本实验室保存的mAb所识别的p54蛋白抗原表位核心序列。ELISA条件优化试验结果显示,以鸡卵白蛋白(OVA)作为N端偶联物的表位串联多肽抗原具有较低的非特异性血清反应背景,当多肽以碳酸盐缓冲液包被(2 μg·mL^-1),血清以封闭液(1%明胶溶液)稀释100倍,辣根过氧化物酶(HRP)标记抗体以0.05% PBST溶液稀释5 000倍时,反应效果最佳;以上述优化后的条件确定了血清抗体阳性临界值为0.339。方法评价试验结果显示,该方法与经典猪瘟病毒(CSFV)、猪繁殖与呼吸综合征病毒(PRRSV)、猪圆环病毒2型(PCV2)、猪细小病毒(PPV)及猪伪狂犬病病毒(PRV)的抗体阳性血清均无交叉反应,能检测低至1 600倍稀释的ASFV阳性血清,具有较好的重复性。用该方法与商品化的ASFV抗体检测试剂盒同时检测320份猪血清样本,两种方法的相对特异性和相对敏感性分别为97.6%与97.3%,总体符合率达97.5%(312/320)。综上表明,本研究建立的多肽间接ELISA方法具有良好的特异性、敏感性及重复性,具有发展为临床诊断试剂盒的潜在应用价值。     

种公猪精液中与繁殖障碍有关的6种病毒的检测

采用PCR和RT-PCR技术,于2006年4月～10月对上海及其周边地区的30个猪场和人工授精站的生产公猪精液样品355份进行了猪繁殖与呼吸综合征病毒(PRRSV)、猪伪狂犬病病毒(PRV)、猪细小病毒(PPV)、猪圆环病毒(PCV)、猪瘟病毒(CSFV)和日本脑炎病毒(JEV)等6种与猪繁殖障碍有关的病毒的检测,结果表明,日本脑炎病毒检测为阴性,检出PRRSV、PRV、CSFV、PPV和PCV阳性数和阳性率分别为6份(1.69%)、9份(2.54%)、5份(1.41%)、75份(21.1%)、6份(1.69%),有一个猪场的5份样品存在PRV和PPV混合感染.     

A sequential study of experimental infection of pigs with porcine circovirus and porcine parvovirus: immunostaining of cryostat sections and virus isolation

The sequential tissue distribution of virus was investigated using virus isolation and immunofluorescence tests in 1-day-old piglets inoculated with porcine circovirus 2 (PCV2) and/or porcine parvovirus (PPV). Enlarged mesenteric lymph nodes were seen in the pig inoculated with PCV2 alone and killed at 26 days post-inoculation (PI). One of the pigs inoculated with PCV2 and PPV and killed at 21 days PI had an enlarged liver. The pig killed at 26 days PI in this group had enlarged liver, kidneys and heart. Histopathological changes were seen in lymphoid tissues of the pigs inoculated with PCV2 alone and killed at 14 and 26 days PI. Similar, but more severe, lesions were observed in the pigs infected with PCV2 and PPV and killed from 10 days PI onwards. Histological lesions of nephritis, pneumonia and hepatitis were also apparent in these animals. Mild nephritis was also seen in the pigs infected with PPV alone and killed at 14 and 26 days PI. Moderate amounts of PPV antigen were detected in tissues from the pigs inoculated with PPV alone and killed at 14 days PI. Low levels of PCV antigen were detected, mainly in lymphoid tissues, in the pigs inoculated with PCV alone and killed at 14 days PI. Low to moderate amounts of PCV antigen were detected in a wider range of tissues in the pig in this group killed at 26 days PI. In the pigs inoculated with both viruses, PPV antigen was detected in tissues of pigs killed from 3 to 26 days PI with maximal amounts detected between 6 and 14 days PI. PCV2 antigen was detected in low to moderate amounts in the tissues of pigs killed at 14 days PI. Large amounts of PCV2 antigen were detected in most of the tissues from pigs in this group killed between 17 and 26 days PI. Virus isolation results for PCV2 generally correlated well with the results for immunofluorescent staining. PPV was isolated from almost all tissues from pigs inoculated with PCV2 and PPV, a much higher incidence of positive tissues than observed for immunofluorescent staining.     

Assay for Antibody in Pig Fetuses Infected with Porcine Parvovirus

Fetal fluids from field cases of fetal death were assayed for antibody to porcine parvovirus (PPV) using 3 different techniques. An indirect immunofluorescent antibody test, a counter immunoelectrophoresis test and a hemagglutination inhibition test were compared. The indirect immunofluorescent antibody test was found to be the most sensitive of the tests employed. The hemagglutination inhibition test apparently suffered from the occurrence of false positive results.