传染性法氏囊病沉淀抗体水平与免疫保护关系的研究

以传染性法氏囊病(IBD)基因工程重组亚单位油乳剂疫苗及其重组活载体疫苗实验室试制品免疫SPF鸡,以法氏囊眼观病变及法氏囊中IBDV抗原检测结果来评定免疫保护效力。结果血清IBDV沉淀抗体水平达到1/8的鸡能抵抗IBDV强毒的攻击,低于1/4的部分鸡不能抵抗IBDV强毒的攻击。经t检验,在以血清IBDV沉淀抗体水平≥1/8所得百分率、血清IBDV沉淀抗体水平≥1/4所得百分率、法氏囊眼观变化正常鸡只百分率及法氏囊中IBDV抗原检测的阴性率之间差异都不显著。表明以血清IBDV沉淀抗体水平≥1/4所得百分率与法氏囊中IBDV抗原检测的阴性率和法氏囊眼观变化正常鸡只百分率一样,适用于评定攻毒免疫保护效力。     

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对1日龄低母源抗体水平雏鸡免疫效果的研究

将鸡传染性法代囊病病毒(IBDV)BX株抗原和IBDV高免血清按一定比例混合,初步制备了无菌的鸡传染性法氏囊病免疫复合物疫苗1~5(分别含有32、8、4、0.5及0.125单位IBDV中和抗体),用鸡传染性法氏囊病免疫复合物疫苗1~5及BX株活疫苗分别免疫1日龄低母源抗体水平雏鸡,免疫后9 d观察法氏囊病变,免疫后28 d采血测定IBDV中和抗体,并用强毒攻击,计算各组疫苗保护率。结果显示,免疫后9 d,复合物疫苗1~3免疫组鸡法氏囊正常,复合物疫苗4、5免疫组和BX株活疫苗免疫组分别有2/10、4/10和5/10的试验鸡法氏囊出现了病变;免疫后28 d,复合物疫苗1~5免疫组和BX株活疫苗免疫组IBDV中和抗体效价分别为8.34log2、9.60log2、9.21log2、7.88log2、9.50log2和9.12log2,攻毒保护率分别为90%、100%、100%、80%、90%和80%。试验结果表明鸡传染性法氏囊病免疫复合物疫苗2、3(分别含8、4单位IBDV中和抗体)免疫1日龄低母源抗体水平的雏鸡效果最好,攻毒保护率能达到100%。     

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。     

鸡传染性法氏囊病免疫复合物疫苗对1日龄中等母源抗体水平雏鸡免疫效果的研究

将鸡传染性法氏囊病免疫复合物疫苗和BX株活疫苗分别免疫1日龄中等母源抗体水平京红雏鸡,同时免疫1日龄SPF雏鸡作对照,免疫后第9天观察法氏囊病变,免疫后第28天采血测定IBDV中和抗体,并用强毒攻击,计算各组疫苗保护率。结果显示,免疫后第9天,免疫复合物疫苗组SPF雏鸡和京红雏鸡法氏囊均正常,BX株活疫苗组SPF雏鸡法氏囊出现了萎缩病变;免疫后第28天,对照SPF雏鸡和京红雏鸡的免疫复合物疫苗组、BX活疫苗组IBDV中和抗体效价分别为9.2log2、8.5log2和 7.2log2、4.4log2,攻毒保护率均为100%。试验结果表明免疫复合物疫苗免疫1日龄中等水平母源抗体雏鸡效果很好,能产生较高的中和抗体,攻毒保护率能达到100%。     

不同方法对鸡胚和法氏囊中囊病病毒抗原含量的检测比较

用单抗介导的抗原捕获－酶联免疫吸附试验（AC－ELISA），琼脂扩散试验（ACP）快速诊断试纸条（ISK）对感染同株强毒或弱毒囊病病毒（IBDV）的鸡胚和鸡法氏囊中的病毒抗原效价进行了检测比较，结果表明，上述3种方法测得法氏囊中温毒IBDV抗原效价分别为10^6.0(AC-ELISA),2^-3.0(AGP)t 10^-3.0，测得鸡胚中强毒IBDV抗原效价依次为10^-1.0,0和0。强毒株接种鸡胚后，只有第1代鸡胚组织可被AC－ELISA测到低效价的IBDV抗原，而第2代以后则未能测到病毒抗原，弱毒疫苗株IBDV感染鸡后，法氏囊中可测到低效价抗原，但感染鸡胚后则无可测性病毒抗原。     

鸡传染性法氏囊病活疫苗与鸡痘活疫苗联合免疫效果研究

鸡传染性法氏囊病(IBD)活疫苗与鸡痘活疫苗通过颈部皮下注射途径,同时接种1日龄出雏鸡,检测2种活疫苗联合免疫的安全性和免疫效力。将2种活疫苗同时免疫SPF雏鸡,免疫后21天用传染性法氏囊病病毒(IBDV)强毒和鸡痘强毒进行攻毒,观察试验组与对照组的攻毒保护情况。结果表明:安全性试验结果显示,免疫后14天内观察所有鸡的精神、食欲和生长发育均正常;剖检所有试验鸡脏器均未见异常,说明2种活疫苗联合免疫SPF雏鸡后是安全的。效力检验结果显示:免疫后21天,分别用鸡痘强毒和法氏囊强毒进行免疫鸡和对照鸡攻毒,鸡痘部分:攻毒后,对照鸡均发痘,免疫鸡无不良反应,未引起全身痘,获得10/10保护;法氏囊部分:攻毒对照鸡法氏囊病变10/10,免疫鸡法氏囊无病变。研究表明2种活疫苗联合免疫雏鸡后,可同时抵御IBDV强毒与鸡痘强毒株的攻击,保护效果良好。结论:IBD与鸡痘活疫苗联合免疫,对雏鸡安全,免疫保护效果好,避免多次免疫对雏鸡带来的应激反应,提高养殖经济效益。     

鸡传染性法氏囊病模拟抗原苗免疫作用的探讨

用鸡传染性法氏囊病毒（IBDV）免疫雏鸡，纯化其IgG(Ab1)免疫兔制备Ab2,Ab2经正常鸡IgG(NC-IgG）和IBD抗原（Ag）吸收后，加佐剂免疫雏鸡，免疫保护指数：Ab2组分别为：100％、100％、90％；对照组：0％。重复实验：50只雏鸡接种3次Ab2免疫，能抵抗IBD强毒攻击，该试验证实：IBD模拟抗原苗在IBD免疫中的应用价值。     

鸡新城疫－传染性支气管炎－传染性法氏囊病三联灭活疫苗对不同日龄雏鸡的免疫效力研究

为评估鸡新城疫（ND）-传染性支气管炎（IB）-传染性法氏囊病（IBD）三联灭活疫苗对不同日龄和不同水平母源抗体雏鸡的免疫效力和持续期,本试验用该疫苗免疫7、14、21日龄SPF雏鸡和有母源抗体的普通雏鸡,免疫后采血测定ND血凝抑制抗体（HI Ab）、IB血凝抑制抗体（HI Ab）及IBD中和抗体（NA）,并用传染性法氏囊病病毒（IBDV）强毒攻击。结果显示,7日龄SPF雏鸡免疫后21 d ND HI抗体、IB HI抗体及IBD中和抗体效价分别为7.9log2、6.9log2和14.1log2,SPF鸡日龄越大,抗体水平越高;28日龄SPF鸡免疫后3个月,0.3 mL免疫剂量组试验鸡ND HI、IB HI及IBD中和抗体效价分别达6.5log2、6.1log2和13.6log2,IBDV攻毒保护率均为100%（10/10）;不同日龄普通雏鸡免疫效果与SPF鸡试验一致,抗体水平随鸡日龄增大而升高,IBD攻毒保护率也都达到100%（10/10）。试验结果证实,鸡新城疫-传染性支气管炎-传染性法氏囊病三联灭活疫苗可使7、14及21日龄SPF雏鸡和普通雏鸡产生良好的免疫力,对雏鸡的免疫期至少为3个月。     

Study on the Immunity Effect of Infectious Bursal Disease Immune Complex Vaccine on One-day Old Moderate Maternal Antibody Chick

One-day-old moderate maternal antibody Jinghong chickens and SPF chickens were vaccinated with infectious bursal disease (IBD) immune complex (IC) vaccine and BX strain live vaccine,respectively,pathological changes of bursa of fabricius in chickens were observed at the 9th day after immunization.On the 28th day after immunization,blood samples were taken and the IBDV neutralizing antibody were tested,meanwhile experimental chickens were challenged with high virulent IBDV,the protective rates of experimental groups were calculated.The results showed that at the 9th day after immunization,the bursa of fabricius in SPF and Jinghong chickens were normal in IC vaccine group,however atrophic changes of bursa of fabricius in BX strain live vaccine group were shown.At the 28th day after immunization,the IBDV neutralizing antibody of IC vaccine group and BX strain live vaccine group in SPF and Jinghong chickens were 9.2log2,8.5log2,7.2log2 and 4.4log2,respectively,while 100% protection rates were provided.The results provided that IC vaccine had better immunity effect on one-day-old moderate maternal antibody chicken,high levels of neutralizing antibodies against IBDV were produced and protection rates were 100%.     

Study on the Immunity Effect of Immune Complex Vaccine for Infectious Bursal Disease on One-day Old Low Maternal Antibody Chicken

Five kinds of infectious bursal disease (IBD) immune complex (IC) vaccines were prepared with infectious bursal disease virus (IBDV) BX strain mixed with IBDV hyperimmune serum according to a certain proportion (containing 32, 8, 4, 0.5 and 0.125 units IBDV neutralizing antibody, respectively).One-day old low maternal antibody chickens were vaccinated with IBD IC vaccines 1 to 5 and BX strain live vaccine, respectively, pathological changes of the bursa of fabricius in chickens were observed at the 9th day after immunization.On the day of 28 after immunization, blood samples were taken and the IBDV neutralizing antibody were tested, meanwhile all experimental chickens were challenged with high virulent IBDV, the protective rates of vaccines were calculated.The results showed that at the 9th day after immunization, the bursa of fabricius were normal in IC vaccine 1, 2 and 3 groups, however 2/10, 4/10 and 5/10 of pathological changes of the bursa of fabricius in IC vaccine 4, 5 groups and BX strain vaccine group, respectively.At the 28th day after immunization, the IBDV neutralizing antibodies in IC vaccine 1, 2, 3, 4, 5 groups and BX strain vaccine group were 8.34log2, 9.60log2, 9.21log2, 7.88log2, 9.50log2 and 9.12log2, while 90%, 100%, 100%, 80%, 90% and 80% protection rates were provided, respectively.The results showed that IBD IC vaccines 2 and 3 (containing 8, 4 units IBDV neutralizing antibody, respectively) had the best immunity effect on one-day old low maternal antibody chickens, protection rates were both 100%.     

Immunoreactivity and morphological changes of bursal follicles in chickens infected with vaccine or wild-type strains of the infectious bursal disease virus

Infectious bursal disease (IBD) is characterized by immunosuppression due to the depletion of lymphocytes in the atrophied bursa of Fabricius (BF). We have sometimes encountered contradictory findings: chickens infected with the vaccine IBD virus (IBDV) strain have sometimes exhibited a highly atrophied BF, but not immunosuppression. In this study, chickens administered vaccine or wild-type strains of IBDV were later vaccinated with the B1 strain of the Newcastle disease virus (NDV). Bursal changes were examined histologically with a focus on the bursal follicle. The immunoreactivity to NDV was also evaluated with the hemagglutination inhibition test. In gross examination, we observed a few chickens with a severely atrophied BF in vaccine strain-administered groups (vaccine groups), and the level of severity was the same as that in the wild-type strain-administered group (wild-type group). However, these chickens retained humoral antibody responses to NDV and were revealed to possess a higher number of bursal follicles than those of the wild-type group. These results indicated that macroscopic evaluation dose not accurately reflect the immunoreactivity and degree of bursal damage in IBDV-administered chickens. We also found non-immunosuppressed chickens in the wild-type group. These non-immunosuppressed chickens retained a significantly higher number of normal follicles and total follicles according to our statistical analysis. Furthermore, a high correlation coefficient between the NDV-HI titer and the number of normal follicles was found in the wild-type group. These results implied that the retained number of normal follicles is important for the immunoreactivity of chickens infected with IBDV.     

雏鸡在感染IBDV后红细胞免疫功能变化的研究

在经ＩＢＤ弱毒苗免疫和未免疫的３０～５９日龄ＡＡ鸡研究了感染ＩＢＤＶ后红细胞免疫功能的变化。结果表明：从以ＩＢＤＶ攻毒前１天到攻毒后头５天内,未免疫攻毒鸡（Ａ组）和免疫攻毒鸡（Ｂ组）ＲＢＣ－ＣＲ１花环率降低或显著降低,而未免疫未攻毒鸡（Ｃ组）没有类似变化,高于Ｂ组,明显高于Ａ组,以后Ａ和Ｂ组逐渐回升到攻毒前水平。Ａ和Ｂ组ＲＢＣ－ＩＣ花环率在ＩＢＤＶ攻毒后第５天明显降低,均显著低于Ｃ组水平,以后Ａ组仍处于较低水平上变动,Ｂ组即逐渐回升,三组比较,Ａ组仍低于Ｃ组,同时也低于Ｂ组。     

Humoral and cell-mediated immune responses in chickens with infectious bursal disease

Primary and secondary immune responses to Newcastle disease virus (NDV) was evaluated in chickens infected with infectious bursal disease virus (IBDV) at one and 28 days of age. The geometric mean primary hemagglutination-inhibition antibody titers (GMT) of chickens infected with IBDV at one day of age was significantly lower (P less than or equal to 0.01) than those infected at 28 days of age. Infection with IBDV had no influence on secondary immune response to NDV. The effect of IBDV infection at one day of age on the cell-mediated immunity of chickens was evaluated by skin allograft acceptance or survival time. There was no significant difference between the percentage of grafts accepted in IBDV infected and noninfected control chickens. However, the mean graft survival time in the IBDV infected chickens was significantly longer (P less than or equal to 0.05) than those in the control group. This suggested a suppression of cell-mediated immunity due to IBDV infection.