禽流感病毒重组核蛋白ELISA诊断技术的研究

用表达禽流感病毒（ＡＩＶ）核蛋白基因的杆状病毒感染Ｓｆ９昆虫细胞。以其表达产物制备抗原,建立了以杆状病毒系统表达的ＡＩＶ核蛋白为抗原的禽流感间接酶联免疫吸附试验诊断技术（ｒＮＰ－ＥＬＩＳＡ）。其抗原最适包被量为０．６μｇ／孔,等检血清最适稀释度为１：２００,酶标抗体使用浓度为１：１０００。根据对１４０份ＳＰＦ鸡血清检测结果的统计分析,确定其判定标准为ＯＤ均为阴性;检测Ａ型ＡＩＶ１５个不同亚型（Ｈ１￣Ｈ１５）毒株的特异性血清均为阳性;对人工接种ＡＩＶ的ＳＰＦ鸡第３天即能检出抗体,到第１６２天试验结束时检测仍为阳性。其批内和批间重复试验的变异系数分别在２．９％￣７．２％和３．４％￣９．８％之间。对３１３８份鸡血清进行监测,ｒＮＰ－ＥＬＩＳＡ与全病毒间接ＥＬＩＳＡ与全病毒间接ＥＬＩＳＡ（ＡＩＶ－ＥＬＩＳＡ）、琼脂扩散     

检测鸡慢性呼吸道病抗体ELISA方法的建立

用败血支原体（ＭＧ）Ａ５９６９株制备ＥＬＩＳＡ抗原,与抗鸡ＩＧ单抗ＩＢ７酶结合物建立了检测鸡血清抗体水平的间接ＥＬＩＳＡ方法,交叉试验、阻断试验、重复性试验等表明该方法重复性好、特异性强、灵敏度高。确立了将鸡血清６４倍稀释监测ＥＬＩＳＡ效价（ＥＴ）的回收方程ｙ＝１．３８３＋０．２２４ｘ,可用于定量测定,血凝抑制试验（ＨＩ）与ＥＬＩＳＡ比较试验表明,ＥＬＩＳＡ法比ＨＩ试验敏感性高４倍以上。     

用ELISA检测牛血清中的牛病毒性腹泻病毒抗体

一般均用血清中和（ＳＮ）试验和间接免疫荧光（１１Ｆ）试验检测牛血清中的抗牛病毒性腹泻病毒（ＢＶＤＶ）抗体，本文用ＳＮ和１１Ｆ敏感性相当的ＥＬＩＳＡ检测ＢＶＤＶ抗体，共测定４７２份牛血清，有７９．２％为阳性。ＥＳＩＳＡ与ＳＮ呈正相关，表明ＥＬＩＳＡ可用于ＢＶＤＶ的常规诊断。     

用抗传染性氏囊病毒单克隆抗体建立夹心阻断ELISA检测鸡血清抗体及 …

用酶标记抗传染性法氏囊病毒（ＩＢＤＶ）单克隆抗体，建立夹心阻断ＥＬＩＳＡ，检测ＩＢＤＶ鸡血清抗体。用Ｄ７８细胞毒免疫２４日龄的雏鸡，每周采血一次，共４次，用夹心阻断ＥＬＩＳＡ、微量细胞中和试验（ＶＮ）、琼脂扩散试验（ＮＧＰ）检测鸡血清抗体，结果表明：夹心阻断ＥＬＩＳＡ同ＶＮ之间具有较高的相关性（ｒ＝０．８１２６），与ＡＧＰ的相关性较低（ｒ＝０Ｘ．７５７５）。     

用ELISA法检测犬细小病毒抗体

本文采用吸附豚鼠犬细小病毒（ＣＰＶ）多克隆抗体的微量板，进行间接酶免疫测定（ＥＬＩＳＡ）检测犬血清中的ＣＰＶ抗体。结果，ＥＬＩＳＡ抗体效价比血凝抑制抗体（ＨＩ）效价高，与ＨＩ效价的相关系数ｒ＝０．７８。     

小鼠PVM血清抗体I—ELISA检测法的建立及其应用

对实验小鼠感染小鼠肺炎病毒（ＰＶＭ）用间接酶联免疫吸附试验（Ｉ－ＥＬＩＳＡ）进行检测,其敏感性、特异性、重复性和稳定性的达到满意效果。结果显示,用ＰＶＭ接种ＢＨＫ２１细胞经初、高、超差速离心浓缩制备的抗原,与仙台病毒,小鼠肝炎 呼肠孤病毒３型的免疫小鼠血清抗体不产生交叉反应,阻断抑制率大于５０％;Ｉ－ＥＬＩＳＡ与ＨＩ对５０份小鼠血清检测其阳性检出率分别为３０％和２０％;将制备的检测抗的在－２０℃保     

快速检测鸡新城疫病毒的聚乙二醇单抗夹心ELISA试验的建立和应用

以抗鸡新城疫病毒（ＮＤＶ）单抗夹心ＥＬＩＳＡ试验为基础，在６０００，建立了ＰＥＧ－ＥＬＩＳＡ法，使用此法检测临诊样品，与单抗夹心ＥＬＩＳＡ相比，时间缩短７０分钟且提高了ＯＤ４９０值，易于识别。结果表明，ＰＥＧ－ＥＬＩＳＡＩ法具有实际应用价值。ＰＥＧ能加强抗原－抗体反应的速率和强度，这种效应在固相夹心ＥＬＩＳＡ第二步表现尤其明显。ＰＥＧ的这种非特异性效应对于检测其它抗原或抗体的ＥＬＩＳＡ试验可能具有     

一种检测猪生殖——呼吸道综合征的ELISA抗原的制备

利用ＴｒｉｔｏｎＸ－１００助溶，由猪生殖－－呼吸道综合征病毒（ＰＲＲＳＶ）感染的ＭＡＲＣ－１４５细胞可制备出高纯度的ＥＬＩＳＡ抗原。这一技术消除了涉及到ＰＲＲＳＶ抗的及细胞抗在的常见本底反应。将这种高质量抗原应用到检测抗ＰＲＲＳＶ抗体的间接ＥＬＩＳＡ中，辅以一咱有效的血清封闭稀释剂可消除血清样品的非特异性反应。这种ＥＬＩＳＡ技术比间接免疫荧光试验（ＩＦＡ）更为敏感；特别是对感染后期血清有高度特异性     

应用间接酶联免疫吸附试验检测鸡传染性法氏囊病病毒

用制备的抗鸡ＩｇＧＭｃＡｂ－ＨＲＰ作为免疫试剂，以ＩＢＤＶ的高免阳性鸡血清作为抗体，用间接ＥＬＩＳＡ法检测经ＩＢＤＶ强毒攻击的各脏器含毒情况，同时与ＡＧＰ法进行比较。结果表明两种方法具有良好的平行关系，间接ＥＬＩＳＡ法比ＡＧＰ法更为敏感；攻毒鸡的法氏囊带毒最多，而在脾、胸腺、肾中均未检出病毒抗原。     

间接酶联免疫吸附试验检测禽流感抗体的最佳工作条件

禽流感病毒（ＡＩＶ）感染的鸡胚囊液经差速离心后,再经蔗糖密度梯度离心,提纯ＡＩＶ,纯化的ＡＩＶ经ＮＰ４０处理并反复冻融,即为ＡＩＥＬＩＳＡ抗原,用该抗原包被聚苯乙烯微量反应板,将健康鸡ＩｇＧ提纯后免疫兔,制备兔抗鸡ＩｇＧ用过碘酸钠法制备辣根过氧化物酶标记的兔抗鸡ＩｇＧ,确立了间接酶联免疫吸附试验（ＥＬＩＳＡ）检测禽流感抗最适工作条件,即：抗原包被浓度１．９～３．８μｇ／ｍｌ,每孔１００μｌ４℃冰箱     

检测禽流感病毒抗体的重组核蛋白间接ELISA方法的建立

以大肠杆菌系统表达的H9N2亚型禽流感病毒（AIV）核蛋白（NP）为抗原，建立了禽流感间接酶联免疫吸附试验抗体检测技术（NP—ELISA）。对263份待检血清（包括临床收集的243份血清和20份H9N2亚型AIV免疫鸡阳性血清）进行检测，NP—ELISA与琼脂免疫扩散试验（AGP）的总符合率为83．3％，与血凝抑制试验（HI）的总符合率为92％。特异性试验表明，NP—ELISA方法可以检测H5、H7和H9亚型AIV特异性抗体，检测为阳性的血清样品能够被阳性鸡胚尿囊液阻断。敏感性试验证实，NP—ELISA最早可以检测鸡感染后7d的血清样品，并于感染后10d确定100％血清阳性，而AGP检测直到首免后21～28d才出现部分血清阳性，HI检测直到10～14d才出现部分血清阳性，并且NP-ELISA要比HI敏感4～40倍。试验证明，NP—ELISA是检测AIV血清型特异性抗体的一种特异、敏感、快速、经济的血清学检测技术。     

Comparative serological evaluation of avian influenza vaccine in turkeys

Four- and six-week-old turkeys were vaccinated subcutaneously using avian influenza virus (AIV) A/Duck/613/MN/79 (H4N2) killed oil-emulsion vaccine. Sequential serological tests using agar gel precipitin (AGP), hemagglutination inhibition (HI), and enzyme-linked immunosorbent assay (ELISA) for measuring antibodies to AIV were performed up to 4 weeks postvaccination, when birds were challenged intranasally using A/Turkey/MN/80 (H4N2) live AIV. The ELISA was 25 to 1600 times more sensitive than the HI test and was able to detect antibody production earlier than the HI test. All turkeys with an ELISA titer of greater than or equal to 800 were protected against homologous challenge, as measured by virus recovery 3 days postchallenge. Four turkeys out of 20 serologically negative by AGP and HI tests but ELISA-positive were protected.     

Detection of antibodies in serum and egg yolk following infection of chickens with an H6N2 avian influenza virus.

Active serologic surveillance programs to detect avian influenza viruses (AIVs) in table egg-laying chickens have been initiated by several states as a response to the economic threat posed by these viruses. Most outbreaks of avian influenza in domestic poultry are caused by mildly pathogenic AIVs. In the study reported here, infection by an H6N2 AIV was used as a model of mildly pathogenic AIV infections in egg-type chickens. The total number of eggs laid by 5 control hens was 619 or 0.904 eggs/day/hen, whereas the total number laid by 10 infected hens was 1,018 or 0.743 eggs/day/hen. The difference in egg production between the 2 groups was not statistically significant (P = 0.38). Anti-influenza antibodies were monitored by use of an agar gel immunodiffusion test and an ELISA for a period of 20 weeks after inoculation. Antibodies in serum developed sooner, peaked at higher levels, and remained at higher levels than did antibodies found in egg yolk, as indicated by ELISA results. For infected chickens, the correlation between serum and egg yolk ratios was 0.66. Serum samples would appear to be preferable to egg yolk samples for surveillance programs intended to identify chicken flocks that may have been infected by an AIV weeks or months before samples are collected.     

Evaluation of a competitive ELISA for antibody detection against avian influenza virus

Active serologic surveillance is necessary to control the spread of the avian influenza virus (AIV). In this study, we evaluated a commercially-available cELISA in terms of its ability to detect AIV antibodies in the sera of 3,358 animals from twelve species. cELISA detected antibodies against reference H1- through H15-subtype AIV strains without cross reactivity. Furthermore, the cELISA was able to detect antibodies produced following a challenge of the AIV H9N2 subtype in chickens, or following vaccination of the AIV H9 or H5 subtypes in chickens, ducks and geese. Next, we tested the sensitivity and specificity of the cELISA with sera from twelve different animal species, and compared these results with those obtained by the hemagglutination-inhibition (HI) test, the "gold standard" in AIV sera surveillance, a second commercially-available cELISA (IZS ELISA), or the agar gel precipitation (AGP) test. Compared with the HI test, the sensitivities and specificities of cELISA were 95% and 96% in chicken, 86% and 88% in duck, 97% and 100% in turkey, 100% and 87% in goose, and 91% and 97% in swine, respectively. The sensitivities and specificities of the cELISA in this study were higher than those of IZS ELISA for the duck, turkey, goose, and grey partridge sera samples. The results of AGP test against duck and turkey sera also showed significant correlation with the results of cELISA (R-value >0.9). In terms of flock sensitivity, the cELISA correlated better with the HI test than with commercially-available indirect ELISAs, with 100% flock sensitivity.     

鸡新城疫-禽流感二联灭活疫苗免疫不同日龄商品肉鸡的效果比较

使用鸡新城疫-禽流感（H9N2 HP株）二联灭活疫苗分别免疫3、7、14日龄三组商品肉鸡各40羽,同时设一组空白对照组。各免疫组及对照组于3、7、14、21、28、35、42日龄采血检测新城疫、禽流感抗体,于21、28、35日龄进行禽流感病毒攻毒,对比不同日龄免疫组的抗体消涨情况及不同日龄禽流感攻毒结果。发现对照组随鸡日龄增加,新城疫与禽流感抗体逐渐下降,在42日龄时下降至0,而不同免疫组新城疫与禽流感抗体均先下降,21日龄左右开始上升,至35日龄新城疫与禽流感抗体升至6log2以上。3日龄免疫组的禽流感免疫保护效果最好,21、28、35日龄时禽流感强毒攻毒保护率均达100%;7日龄免疫组在21、35日龄时禽流感强毒攻毒保护率均达100%,28日龄时禽流感强毒攻毒保护率达70%;14日龄免疫组在28、35日龄时禽流感强毒攻毒保护率均达100%,21日龄时禽流感强毒攻毒保护率只达30%。试验表明,商品肉鸡选择3日龄免疫鸡新城疫-禽流感（H9N2 HP株）二联灭活疫苗时禽流感免疫保护效果最好,采用3日龄免疫程序可以提高新城疫与禽流感的免疫保护效果,减少养殖业的经济损失。     

Heterologous antibodies to evaluate the kinetics of the humoral immune response in dogs experimentally infected with Toxoplasma gondii RH strain

An IgM capture ELISA using heterologous antibodies was developed to evaluate the kinetics of the humoral immune response in dogs experimentally infected with Toxoplasma gondii RH strain. Detection of parasite in tissues from inoculated dogs was evaluated by mouse bioassay and immunohistochemical techniques. Serum samples were obtained at regular intervals up to 62 days post-inoculation (p.i.), when the animals were necropsied and their tissues examined. Antibody levels were measured by IgM capture ELISA (McELISA), indirect hemagglutination (IHA), indirect fluorescent antibody test (IgG-IFAT) and indirect immunoenzymatic assay (IgG-ELISA). All dogs seroconverted but only one exhibited severe clinical signs of infection. IgM antibodies were detected by McELISA from the seventh day on, with decreasing IgM levels around the 27th day. Similar results were obtained from IHA, although McELISA showed earlier and longer detection of IgM antibodies. IgG antibodies were detected from the seventh day on, and throughout the period of observation. Immunohistochemical findings and mouse bioassay revealed the presence of free tachyzoites in tissues of the clinically affected dog only. These results suggest that T. gondii acute infection in dogs shows a remarkably transient IgM synthesis, and this feature may constitute an important marker of active infection. Furthermore, McELISA was shown to be a potential tool to diagnose canine toxoplasmosis.     

抗独特型抗体检测H9亚型禽流感血清抗体

为了探讨用抗独特型抗体替代病毒或病毒亚单位检测H9亚型禽流感血清抗体的可行性,本试验分别用全病毒抗原和抗独特型抗体(Ab2)作检测原,通过琼脂免疫扩散试验(AGP)和间接酶联免疫吸附试验(ELISA)检测了鸡的血清样品。在AGP试验中,分别用Ab2和禽流感病毒(AIV)对10份血清样品检测的符合率为70%。在间接ELISA试验中,Ab2和AIV抗原对10份血清样品检测的符合率为90%。用Ab2间接ELISA试验检测出的血清阳性率(8/10)高于血凝抑制试验(6/10)和AGP试验(5/10)。结果表明,在一定的情况下Ab2可以用来代替具有污染环境风险的病毒抗原来检测抗病毒抗体。     

Development of enzyme-linked immunosorbent assay with nucleoprotein as antigen for detection of antibodies to avian influenza virus

During the avian influenza outbreak of 2003-04 in Southeast Asia, two avian influenza viruses (AIV), one of H5N1 subtype and the other H9N2 subtype, were isolated and identified from local farms. The nudeoprotein (NP) gene of the H5N1 AI isolate was cloned, and the segment encoding amino acid 47-384, which covers its major antigenic domains, was subcloned and expressed in E. coli. Subsequently, the NP (47-384) expression product was purified and used as the diagnostic antigen to develop a NP-based type-specific indirect enzyme-linked immunosorbent assay (ELISA) for detecting antibodies to AI from chicken sera. The ELISA is shown to be specific for AIV and does not cross-react with chicken sera that has antibodies to other avian viruses. The NP(47-384)-ELISA was compared with a hemagglutination inhibition test and a commercial AIV ELISA kit in evaluating 150 sera samples from experimentally AIV-infected or vaccinated specific-pathogen-free (SPF) chickens. Our NP(47-384)-ELISA was more sensitive than the two tests and showed an 82% agreement ratio with the HI test and an 80.67% agreement ratio with the commercial kit. The NP(47-384)-ELISA and the commercial AIV ELISA were used to evaluate 448 field sera samples from diseased chickens or vaccinated chickens during the 2003-04 AI outbreak in China. The two ELISA tests had a 95% agreement ratio. We conclude that the NP(47-384)-ELISA developed in our laboratory was specific and sensitive and it has great application potential in China's long-term prevention and control of AI.     

An enzyme-linked immunosorbent assay for detection of avian influenza virus subtypes H5 and H7 antibodies

Background

Avian influenza virus (AIV) subtypes H5 and H7 attracts particular attention because of the risk of their potential pathogenicity in poultry. The haemagglutination inhibition (HI) test is widely used as subtype specific test for serological diagnostics despite the laborious nature of this method. However, enzyme-linked immunosorbent assays (ELISAs) are being explored as an alternative test method.H5 and H7 specific monoclonal antibodies were experimentally raised and used in the development of inhibition ELISAs for detection of serological response specifically directed against AIV subtypes H5 and H7. The ELISAs were evaluated with polyclonal chicken anti-AIV antibodies against AIV subtypes: H1N2, H5N2, H5N7, H7N1, H7N7, H9N9, H10N4 and H16N3.

Results

Both the H5 and H7 ELISA proved to have a high sensitivity and specificity and the ELISAs detected H5 and H7 antibodies earlier during experimental infection than the HI test did. The reproducibility of the ELISA’s performed at different times was high with Pearson correlation coefficients of 0.96-0.98.

Conclusions

The ELISAs are a potential alternative to the HI test for screening of large amounts of avian sera, although only experimental sera were tested in this study.