鸡传染性法氏囊病免疫复合物疫苗的安全性和免疫效力试验

用鸡法氏囊病免疫复合疫苗(IBDV-Icx)和常规IBD活疫苗分别免疫1日龄商品鸡和SPF鸡,进行疫苗的安全性及免疫效力比较.免疫后8d检测,IBDV-Icx免疫组鸡的法氏囊未见明显萎缩,而传统弱毒疫苗免疫组鸡的法氏囊萎缩明显;免疫后28d各组用IBDV标准强毒株进行攻击,IBDV-Icx免疫组鸡的攻毒保护率均为10/10,常规IBD活疫苗对照组分别为8/10及9/10.免疫后3个月,IBDV-Icx免疫组血清抗体可达AGP1∶32,攻击强毒仍为10/10保护,而常规IBD活疫苗免疫后2个月抗体AGP为0,攻毒保护率为1/10,免疫后3个月时攻毒10/10发病.     

鸡传染性法氏囊病免疫复合物疫苗与活疫苗免疫鸡病毒载量和免疫效果的比较研究

为比较鸡传染性法氏囊病(IBD)免疫复合物疫苗与活疫苗免疫鸡法氏囊及外周血淋巴细胞(PBMC)中的病毒载量及免疫效果,本研究采用IBD免疫复合物疫苗和鸡传染性法氏囊病毒(IBDV)BX株活疫苗免疫1日龄SPF鸡,于免疫后7d、14d、21d、28d、35d、42d采用SYBRGreenI荧光定量PCR、ELISA方法及中和试验检测免疫鸡法氏囊和PBMC中IBDV载量和免疫鸡血清中IBDV抗体滴度,并攻毒,计算两种疫苗的保护率。结果显示,活疫苗免疫7d时IBDV在法氏囊和PBMC中的载量均比其它时间点的高,在14d时到达到最高,之后逐渐下降;两种疫苗刺激产生的IBDV抗体滴度随免疫时间的延长呈升高趋势;在免疫后7d攻毒两种疫苗的保护率均为0,其它时间的攻毒保护率均为100%。本研究结果表明,IBD免疫复合物疫苗与活疫苗免疫后病毒在鸡体内开始大量复制的时间并不相同,但免疫效果基本相同。本实验为IBD免疫复合物疫苗的研发提供实验依据。     

三种鸡传染性法氏囊病活疫苗免疫效力的比较研究

试验用3种不同亚型的鸡传染性法氏囊病（IBD）疫苗毒株制备单价、双价及三价活疫苗。将3种苗分别免疫10－14日龄的SPF鸡，于免疫后1－4周内用法氏囊标准强毒株攻击；攻毒后第3d、14d观察法氏囊病理变化并测定法氏囊重／体重比值；同时检测免疫鸡血清中和抗体水平。试验结果表明，双价及三价活疫苗有明显高的攻毒保护率；血清中和抗体产生早，抗体水平高。     

鸡传染性法氏囊病活疫苗（B87株 CA株 CF株）安全性及免疫效果评价

通过观察疫苗免疫后鸡群的生长情况和临床症状,检测免疫后不同时期鸡群的ELISA抗体水平和攻毒保护率以及对鸡新城疫（ND）疫苗免疫后不同时间鸡群的HI抗体水平,评价和检测鸡传染性法氏囊病活疫苗（B87株 CA株 CF株）在石家庄地区临床应用的安全性、免疫效果、免疫持续期以及是否会产生免疫抑制。结果表明,试验疫苗接种蛋鸡和肉鸡后,均没有观察到因疫苗引起的不良反应,对蛋鸡和肉鸡均安全。疫苗接种蛋鸡后14 d、28 d、42 d、60 d和90 d,接种肉鸡后14 d、21 d、36 d攻毒保护率均达80%以上;商品蛋鸡接种疫苗后90 d其ELISA抗体水平仍高达6500以上。ND HI抗体检测结果表明,试验疫苗接种后对ND疫苗的免疫应答无显著影响,不引起免疫抑制。结论：试验疫苗安全、有效,质量稳定,适用于预防鸡传染性法氏囊病。     

传染性法氏囊炎病毒(IBDV)血清Ⅰ型和血清Ⅱ型抗体的鉴别检测

利用血清中和试验(VN),酶联免疫吸附实验(ELISA)和琼脂扩散沉淀试验(AGP)对IBDV血清Ⅰ型和血清Ⅱ型抗体进行鉴别检测。被检血清来自用活毒攻毒鸡和用灭活油佐剂疫苗免疫鸡,血清Ⅰ型和血清Ⅱ型两者之间抗体的差异用VN试验很容易鉴别检出,但用ELISA方法却不能区分两者之间的差异。AGP试验更不能令人满意。目前用于检测IBDV抗体水平的方法主要有VN、AGP和ELISA等。VN试验不仅可鉴别检测血清Ⅰ型和血清Ⅱ型IBDV抗体,而且可鉴别检测同一血清型内不同毒株的抗体。ELISA也同样用于检测鸡的IBDV抗原和抗体,并被广泛应用于测定大型鸡场IBDV的免疫状态。此报道的主要目的是对比ELISA,AGP试验和VN试验检测IBDV血清Ⅰ型和血清Ⅱ型特异性抗体之间差异的敏感性。     

鸡传染性法氏囊病毒病毒样颗粒免疫原性研究

对鸡传染性法氏囊病病毒(IBDV)病毒样颗粒(VLPs)的免疫原性进行了探讨,并将其与鸡传染性法氏囊病活疫苗进行比较。分别用VLPs及VLPs+Poly IC对14日龄非免鸡进行免疫,并用IBDV B87株弱毒商品疫苗作为阳性对照,同时设置空杆粒蛋白组作阴性对照及PBS对照。免疫前进行颈静脉采血,首免后每隔1周进行3次采血,通过间接ELISA抗体水平检测、中和试验和淋巴细胞增殖试验来进行分析比较。抗体水平检测结果显示,首免后第7天,在鸡的体内可检测到IBDV特异性抗体的组别为:VLPs组、VLPs+Poly IC组和B87株组,且在加强免疫后,抗体水平明显增高(P0.05)。首免后第14天,在3组鸡的体内均检测到高水平的抗IBDV中和抗体,且呈快速增长趋势。淋巴细胞增殖试验结果显示,VLPs组、VLPs+Poly IC组和B87株组鸡体内淋巴细胞增殖动态明显高于接种PBS和空杆粒蛋白组的鸡(P0.01),并且在加强免疫后明显提高(P0.05)。动物攻毒保护试验结果显示,攻毒后第2天PBS组和空杆粒蛋白组的鸡均表现出IBD的典型临床症状和病理变化且在攻毒后第6天全部死亡,VLPs组鸡的存活率为88.7%;VLPs+Poly IC组鸡存活率为80%;B87疫苗组鸡存活率为88.7%。器官指数分析结果显示,3组与空白组相比差异不显著(P0.05)。本试验制备的鸡传染性法氏囊病病毒样颗粒疫苗能够诱导机体产生较高水平的体液和细胞免疫应答,具有良好的应用前景。     

不同方法检测猪O型口蹄疫疫苗抗体效价与攻毒保护相关性研究

为评价不同检测方法检测的口蹄疫疫苗抗体效价与免疫保护率的相关性,使用O型液相阻断ELISA、正向间接血凝试验、VP1结构蛋白抗体ELISA三种检测方法对免疫不同类型O型口蹄疫疫苗的60头猪进行血清抗体跟踪测定,免疫21 d后,分别用OZK/93和O/(XJ/10-11/MYA/98)毒株进行攻毒保护实验.数据统计和分析结果显示,0型液相阻断ELISA试验测定的抗体效价与攻毒保护率存在着极显著的正相关性(P＜0.01),相关系数为0.75;正向间接血凝试验测定的抗体效价以及VP1结构蛋白抗体ELISA法测定的S/P值与攻毒保护率之间均不存在线性相关关系(P＞0.05).试验表明,O型液相阻断ELISA抗体检测方法可作为田间猪O型口蹄疫疫苗免疫效果的评价方法.     

犬瘟热病毒DNA疫苗接种犬的免疫保护

用犬瘟热病毒(CDV)囊膜糖蛋白基因(H、F)和核蛋白基因(N)重组质粒DNA和聚乙烯胺(PEI)混合后肌注10只3月龄CDV抗体阴性毕格犬,间隔30 d,共免疫3次,另选择5只犬作为阴性对照.免疫3次后,采用CDV攻毒.对照组呈现出犬瘟热的典型症状和组织病理损害,攻毒3周内,有2只犬衰竭死亡,1只犬症状明显,攻毒第18天外周血淋巴细胞中病毒RNA检测为阳性.DNA疫苗免疫组除出现一过性的体温升高外,未出现明显症状,攻毒后第18天外周血淋巴细胞CDV检测仍为阴性.DNA疫苗免疫后血清ELlSA抗体和病毒中和抗体测定显示,首免后机体激发的ELISA抗体滴度很低(101.25±0.615),二免后开始缓慢升高(101.69±0.285),再次免疫后达到102.051±0.214;中和抗体也呈现以上规律,三免后血清中和抗体为101.75±0.190,攻毒后血清ELISA抗体和中和抗体滴度迅速升高(103.02±0.202和102.41±0.245).试验表明CDV基因免疫对CDV的感染具有较好的保护作用,并能清除进入机体内的病毒.CDV基因免疫只激发较低水平的体液免疫,中和抗体在攻毒前达不到临界保护线(102),但对CDV攻击能产生较好的保护,推测其免疫效力可能源于细胞免疫和记忆性B淋巴细胞.     

IFN-γ-ELISpot方法用于评价猪伪狂犬病疫苗免疫效果

鉴于常用的抗体检测方法不能完整反映免疫猪获得针对猪伪狂犬病毒的保护力,有必要建立猪伪狂犬病病毒(PRV)特异性IFN-γ的酶联免疫斑点检测(ELISpot)方法,并评估伪狂犬病疫苗细胞免疫的免疫效果。依照ELISpot基本操作流程,摸索PRV作为刺激原的最适浓度、外周血单个核细胞(PBMC)密度和作用时间以建立并优化该方法。将20头gB抗体检测阴性猪,随机分为单独弱毒疫苗免疫组、单独灭活疫苗免疫组、弱毒疫苗-灭活疫苗联合组及对照组,免疫后攻毒。利用所建方法,结合gB-ELISA、中和试验及攻毒保护试验,评价上述三种免疫程序的效果。试验结果表明:IFN-γ-ELISpot最佳条件为刺激原浓度2μg·孔~(-1)、外周血单核细胞(PBMC)浓度106·孔~(-1),培养时间36h。一免弱毒疫苗二免灭活疫苗组二免后2周,试验猪中和抗体效价可达1∶14.48,ELISpot斑点数可达(151.8±26.61)个·孔~(-1),且该免疫程序下,试验猪攻毒后体温、鼻拭子排毒及临床症状均低于其余试验组,攻毒8d后仅表现呼吸道症状;单独灭活疫苗免疫组二免后2周,试验猪的中和抗体效价可达1∶32.36,而ELISpot斑点数仅为(40.4±9.07)个·孔~(-1);单独弱毒疫苗免疫组二免后2周,试验猪的中和抗体效价仅为1∶1.36,但ELISpot斑点数可达(189.6±27.36)个·孔~(-1)。综合分析攻毒试验结果和ELISpot斑点数之间的相关性,本试验所建立的IFN-γ-ELISpot可用于猪伪狂犬病疫苗的细胞免疫评估,为免疫程序的评价和选择提供有效手段。     

AE灭活疫苗ELISA抗体与攻毒保护效果试验

用禽脑脊髓炎灭活疫苗免疫28日龄SPF鸡10只,5只对照不免疫,免疫后21d采血分离血清,ELISA抗体效价检测,采血后马上进行攻毒,攻毒后观察统计发病情况,在试验鸡出现典型症状及攻毒后21d试验结束日,存活鸡全部采血测抗体,对比抗体与攻毒保护效果之间的关系。结果表明:攻毒前免疫鸡ELISA抗体阳性率为80%,攻毒保护效果80%,对ELISA抗体阳性鸡攻毒均有保护。     

Differentiation between antibodies to serotypes 1 and 2 infectious bursal disease viruses in chicken sera

The usefulness of the virus neutralization (VN) test, the enzyme-linked immunosorbent assay (ELISA), and the agar gel precipitin (AGP) test in differentiating antibodies to infectious bursal disease virus serotypes 1 and 2 was investigated. Sera examined were from chickens that were challenged with live virus or inoculated with inactivated oil-emulsion IBDV vaccines or were both challenged and inoculated. Antibodies to serotypes 1 and 2 were differentiated by the VN test but not by the ELISA, and the AGP test was less than satisfactory.     

An enzyme-linked immunosorbent assay for the detection of antibody against avian influenza virus

An enzyme-linked immunosorbent assay (ELISA) was developed for detecting antibody to type A avian influenza (AI) virus. The sensitivity and group specificity of the AI-ELISA were compared with those of the agar-gel-precipitin test (AGPT) and the hemagglutination-inhibition (HI) test under conditions of both controlled and field exposure. During the course of temporal experimental infection (0-76 days) of specific-pathogen-free (SPF) chickens with AI subtype Hav9N2, the AI-ELISA was able to detect specific AI antibody as early as 8 days postinoculation (PI), and it measured rising levels of antibody through 35 days PI, at which time the chickens were re-exposed to AI virus. Conversely, AGP tests were negative through 35 days PI, and HI tests began to detect low levels of AI antibody only at 21 days PI. Following a secondary infection at 35 days PI with the same AI subtype, all tests measured rising levels of AI-specific antibody (35-76 days PI). However, the AGP test was positive at only the 7- and 14-day samplings postsecondary immunization. Under field conditions, the AI-ELISA was able to detect serum AI antibody in flocks from which highly pathogenic AI was isolated, but the AGP tests of these sera were negative.     

Evaluation of serum and secretory antibody responses to an immunodominant recombinant merozoite surface antigen, p150, using a sensitive enzyme-linked immunosorbent assay

An equation obtained from linear-regression analysis of positive/negative ratios and log of enzyme-linked immunosorbent assay (ELISA) titers of coccidia-immune serum samples was used to accurately predict the antibody titers of chickens immunized with a recombinant merozoite surface protein (p150). Chickens immunized twice intramuscularly with the recombinant p150 antigen emulsified in complete Freund's adjuvant developed a dose-dependent anti-p150 antibody response 14 days after primary immunization. Serum IgG and IgM and secretory biliary IgA antibodies were detected 2 months after primary immunization. Oral challenge with live Eimeria parasites significantly enhanced both the serum and secretory anti-p150 antibody titers. These results indicate that vaccination of chickens with the p150 recombinant merozoite antigen can induce a parasite-specific host immune response.     

Enzyme-linked immunosorbent assay for the detection of antibodies to infectious bronchitis virus

An enzyme-linked immunosorbent assay (ELISA) for antibodies to avian infectious bronchitis (IB) virus is described. The immune response of chickens following vaccination with IB virus was monitored using this test, and the titers were compared with those obtained by serum neutralization. The ELISA appears to be suitable for IB serology.     

A comparison of gel diffusion, fluorescent antibody and virus isolation methods in experimental and natural cases of infectious bursal disease.

In studies with chicks inoculated with the Sk-1 strain of infectious bursal agent the bursa of Fabricius was found to be the tissue of choice for virus isolation as well as for use in the fluorescent antibody test and the agar gel diffusion test. In separate experiments positive results were obtained until postinoculation days 3 or 4 by the agar gel diffusion test, 5 or 6 by the fluorescent antibody test and 14 by the virus isolation method, respectively. Bursas from chickens involved in seven natural outbreaks of infectious bursal disease were then examined by these three methods. Virus was isolated from six outbreaks and infectious bursal agent antigen was demonstrated in three by the agar gel diffusion test method and seven (three by direct examination and four after one passage in chicks) by the fluorescent antibody test method. Passage in chicks was required when nonspecific fluorescence complicated the interpretation of fluorescent antibody test results.     

Detection of antibodies against serotypes 1 and 2 infectious bursal disease virus by commercial ELISA kits

Two distinct serotypes of infectious bursal disease virus (IBDV) are recognized in chicken and turkey flocks in the United States. Serologic testing of chicken flocks for serotype 1 viruses is routinely performed to monitor disease status and vaccination. Earlier studies indicated that enzyme-linked immunosorbent assay (ELISA) test detects antibodies to both serotypes of the virus, while the virus neutralization (VN) test is serotype specific. It is useful to evaluate currently available commercial ELISA kits for their ability to differentiate between antibodies elicited by the two serotypes. Three trials were performed in which chickens were orally inoculated with either a high or a low dose of serotype 1 STC or serotype 2 OH strains of IBDV. Sera collected at 0, 7, 14, and 21 days from these chickens and antisera procured from naturally infected broiler (n=20) and layer (n=30) flocks were tested with five different commercial ELISA kits and by VN. All ELISA kits detected different levels of antibodies elicited against serotype 1 of the virus and moderate and high levels of antibodies against serotype 2 virus. A correlation existed between the ELISA and the VN titers of experimentally infected chickens. All serum samples tested from the commercial layer flocks and 65% of the broiler flocks had antibodies against the OH strain. However, no correlation between the VN titers and ELISA titers was observed for the commercial broilers and layers sera by the majority of the kits. The results indicated that currently available commercial ELISA kits detect antibodies elicited by the two serotypes of IBDV. Hence, the prevalence of serotype 2 antibodies in the flocks should be considered while determining antibody profiles of the flocks against serotype 1 viruses.     

Detection of antibodies against infectious bursal disease virus: a comparison of three serological methods

Four different oil emulsion infectious bursal disease virus (IBDV) vaccines were inoculated into four-week-old specific pathogen-free chickens. At weekly intervals for five weeks, sera were obtained from the vaccinated birds and from uninoculated control birds and examined for antibodies against IBDV by enzyme-linked immunosorbent assay (ELISA), the quantitative agar gel precipitin (QAGP) test and the virus neutralisation (VN) test. There was a highly significant correlation between the mean responses to all tests; the highest correlation (0.818) was between VN and QAGP and the lowest (0.573) between QAGP and ELISA. Generally the ELISA detected positive sera earlier than the VN test which in turn was more sensitive than the QAGP test. The ELISA and QAGP test were less variable, more reproducible and easier to perform than the VN test.     

H9亚型禽流感油乳剂灭活苗免疫、免疫后攻毒及人工感染鸡抗体的监测

本研究采用ＡＧＰ、ＨＩ等试验方法，对经Ｈ９亚型禽流感油乳剂灭活苗免疫、免疫后攻毒以及经Ｈ９Ｎ２活毒人工感染后的ＳＰＦ鸡抗体产生、消长规律进行了测定，结果表明人工感染ＳＰＦ鸡和免疫鸡一周后，ＡＧＰ的检出率即可达到１００％；Ｈ９亚型禽流感油乳剂灭活苗自免疫后一周内即可产生ＨＩ抗体，２１－２８天达到高峰，并能对相同亚型病毒感染引发良好的免疫反应。