雏鸡在感梁IBDV后血浆cAMP,cGMP和IL—2水平变化

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后血浆ｃＡＭＰ、ｃＧＭＰ和ＩＬ－２水平动态变化。结果表明：示免疫攻毒鸡（Ａ组）、免疫攻毒鸡（Ｂ组）和未免疫未攻毒鸡（Ｃ组）在ＩＢＤＶ攻毒前１天血浆ＣＡＭＰ和ＣＧＭＰ水平Ｂ组明显高于Ａ和Ｃ组,ＣＡＭＰ／ＣＧＭＰ幽会同样是Ｂ组高于或明显高于Ａ和Ｃ组,ＩＬ－２水平三组之间无明显差异。在攻毒后的头５天内,Ｂ和Ｃ组ＣＡＭＰ明显升高,而Ａ组     

法氏囊病毒感染对肉鸡内分泌机能的影响

用鸡传染性法氏囊病毒（ＩＢＤＶ）弱毒疫苗免疫和强毒感染艾维菌鸡，采用放射免疫分析法（ＲＩＡ）测定血浆甲状腺素（Ｔ３，Ｔ４）、促肾上腺皮质素（ＡＣＴＨ）和皮质酮（Ｆ）来研究ＩＢＤＶ感染对肉鸡内分泌机能的影响。结果表明：ＩＢＤＶ弱毒疫苗免疫使肉鸡产生高效价抗体，血浆ＡＣＴＨ含量升高；ＩＢＤＭ强毒感染导致肉鸡血浆Ｔ２、Ｆ急剧升高，法氏囊肿大，血清中也出现ＩＢＤＶ抗体，但效价显著低下；而ＩＢＤＶ强毒感染曾     

雏鸡在感染IBDV后血浆cAMP、cGMP和IL-2水平变化

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后血浆ｃＡＭＰ、ｃＧＭＰ和ＩＬ２水平动态变化。结果表明：未免疫攻毒鸡（Ａ组）、免疫攻毒鸡（Ｂ组）和未免疫未攻毒鸡（Ｃ组）在ＩＢＤＶ攻毒前１天血浆ｃＡＭＰ和ｃＧＭＰ水平Ｂ组明显高于Ａ和Ｃ组,ｃＡＭＰ／ｃＧＭＰ比值同样是Ｂ组高于或明显高于Ａ和Ｃ组,ＩＬ２水平三组之间无明显差异。在攻毒后的头５天内,Ｂ和Ｃ组ｃＡＭＰ明显升高,而Ａ组没有类似的变化,第５天明显低于Ｂ和Ｃ组,以后Ｂ和Ｃ组仍高于或显著高于攻毒前和同期Ａ组水平。在攻毒后Ａ和Ｂ组ｃＧＭＰ均呈波动性上升趋势,第７天明显高于攻毒前水平并高于Ｃ组,以后Ａ、Ｂ、Ｃ三组均下降,但Ａ组比Ｂ和Ｃ组下降更快。在攻毒后２８天内,Ａ组ｃＡＭＰ／ｃＧＭＰ比值无明显变化,Ｂ组波动上升,Ｃ组处于高水平上,Ｂ和Ｃ组均高于或明显高于Ａ组。血浆ＩＬ２水平Ａ和Ｂ组在ＩＢＤＶ攻毒后的头７天内呈逐渐下降趋势,但Ａ组下降的更剧烈,Ｃ组无明显差异性变化,三组相比,Ｂ和Ｃ组均高于或明显高于Ａ组,以后Ａ和Ｂ组逐渐回升。     

雏鸡感染传染性法氏囊病病毒后血浆肿瘤坏死因子—α和花生四烯？…

选取经伟要性法氏囊病病毒（ＩＢＤＶ）弱毒苗免疫和未免疫的ＡＡ鸡１２０羽,研究了感染ＩＢＤＶ强毒后血浆肿瘤坏因子－α（ＴＮＦ－α）和花生四烯酸代谢物水平的动态变化及相互关系。表明,攻毒后第１天,未免疫攻毒鸡（Ａ组）血浆ＴＮＦ－α即表现较大的变化,至第３天,Ａ组和免疫攻毒鸡（Ｂ组）ＴＮＦ－α显著高于未免疫未攻毒鸡（Ｃ组）,至第５天３个组虽均下降,但Ａ级仍 或明显高于Ｂ、Ｃ组,以后３组间无明显差异;攻毒     

肉用鸡垂体—肾上腺轴与免疫功能关系的研究

以艾维茵肉鸡为试验动物，研究了垂体－肾上腺轴在传染性腔上囊病病毒（ＩＢＤＶ）强毒株攻击时对免疫系统的调节作用。结果表明，用ＩＢＤＶ强毒株攻击后，试验鸡垂体－肾上腺轴活动加强，血清促肾上腺皮质激素（ＡＣＴＨ）和皮质酮（Ｆ）上升，抗ＩＢＤＶ抗体、白细胞介素２（ＩＬ－２）和白细胞介素３（ＩＬ－３）上升，Ｔ淋巴细胞转化率下降。未经ＩＢＤ疫苗免疫的鸡由于免疫系统遭到ＩＢＤＶ破坏，在ＩＢＤＶ强毒株攻毒后，抗Ｉ     

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。     

感染IBDV雏鸡血液激素水平和ANAE阳性淋巴细胞动态变化

为探讨内分泌活动及细胞免疫反应在鸡抗传染性法氏囊病毒（ＩＢＤＶ）感染中的调节作用机制而进行了本研究。结果表明,攻毒后１～５ｄ内,未免疫攻毒鸡（Ａ组）、免疫攻毒鸡（Ｂ组）血浆皮质酮均明显上升,而未免疫未攻毒鸡（Ｃ组）则否。Ａ、Ｂ、Ｃ３组血浆Ｔ４水平攻毒前后无明显变化,Ｔ３除在攻毒后第３天Ａ组明显高于Ｂ、Ｃ组外,其他时间无明显差异性变化。血液ＡＮＡＥ阳性淋巴细胞（％）在攻毒后的１～５ｄ内,Ａ组和Ｂ组明显下降,以后回升,至２８ｄ回复到攻毒前水平,并接近于Ｃ组。Ａ组的ＡＮＡＥ阳性淋巴细胞（％）与皮质酮呈显著负相关,与Ｔ３和Ｔ４无明显相关性。     

鸡群感染IBD强毒对ND免疫抑制的实验观察

６周龄商品ＡＡ肉鸡单独感染鸡传染性法氏囊病强毒后，紧急注射ＩＢＤ高免卵黄，可在２天内得到控制；单独感染新城疫强毒后，紧急注射ＮＤＩ系疫苗，可在５天内得到控制，而混合感ＩＢＤＶ和ＮＤＶ或感染ＩＢＤＶ后继发感染ＮＤＶ，紧急性注射ＮＤＩ系疫苗，未能在７天内控制疫情，由此证明鸡群感染强毒ＩＢＤＶ可对ＮＤ产生严重免疫抑制。     

鸡群感染IBD强毒对ND免疫抑制的实验观察

６周龄商品ＡＡ肉鸡单独感染鸡传染性法氏囊病（ＩＢＤ）强毒（ＩＢＤＶ）后，紧急注射ＩＢＤ高免卵黄，可在２天内得到控制；单独感染新城疫（ＮＤ）强毒后，紧急注射ＮＤⅠ系疫苗，可在５天内得到控制；而混合感染ＩＢＤＶ和ＮＤＶ或感染ＩＢＤＶ后继发感染ＮＤＶ，紧急注射ＮＤⅠ系疫苗，未能在７天内控制疫情。由此证明鸡群感染强毒ＩＢＤＶ可对ＮＤ产生严重免疫抑制。     

应用生物素标记的NDV－cDNA探针检测感染尿囊液中NDV－RNA的初步研究

本文应用聚合酶链反应（ＰＣＲ）技术从构建的新城疫病毒（ＮＤＶ）ｃＤＮＡ文库中扩增含编码Ｆ糖蛋白前体──Ｆｏ酶切位点序列的３５９ｂｐ的Ｆ蛋白基因ｃＤＮＡ片段。将此３５９ｂｐｃＤＮＡ片段经光敏生物素标记后,即成ＮＤＶ－ｃＤＮＡ探针。该探针能特异性地从感染的尿囊液中检测出ＮＤＶ强毒株和疫苗毒株的基因组ＲＮＡ,而不与ＩＢＤｖ－ｄｓＲＮＡ、ＡＩＢｖ－ｓｓＲＮＡ、ＥＤＳ７６－ｄｓＤＮＡ、ＭＤＶ－ｄｓＤＮＡ,ＦＰＶ－ｄｓＲＮＡ及ＡＩＬＶ－ｄｓＤＮＡ发生交叉杂交反应。试验结果表明：尽管该探钎含有编码Ｆｏ蛋白酶切位点序列的碱基顺序,但它还是不能把ＮＤＶ的强、弱毒株区分开。这说明ＮＤＶ强、弱毒株比区域内的碱基存在着相当大的同源性。不过,此探针对ＮＤＶ来说具有特异性,这就为ＮＤＶ的诊断技术开创了基因水平检测的新途径。     

环核苷酸（cAMP／cGMP）与肉鸡内分泌及免疫功能的关系

以艾维茵肉鸡为实验对象，研究了血清环核苷酸与肉鸡内分汔及免疫功能的关系。结果表明，以性法氏囊病病毒（IBDV）强毒株攻击后，肉鸡垂体－肾上腺轴活动加强，并发生针对IBDV的特异性免疫反应，血清cAMP与cGMP含量均上升，但cAMP/cGMP比值保持稳定，提示垂体－肾上腺轴活动加强使cAMP上升与抗IBDV特异性免疫细胞内效应大分子的合成有关，而cAMP/cGMP比值的稳定则是保持一种高阈平衡，以维持内环境的稳态。由于IBDV强毒株破坏了机体免疫系统，未经IBDV疫苗免疫的肉鸡cAMP、抗IBDV抗体和IL－2的上升幅度均比经IBDV疫苗免疫的肉鸡小。     

Inclusion body hepatitis as a primary disease in broilers in Saskatchewan, Canada

In recent years inclusion body hepatitis (IBH) has emerged as an economically important disease in Western Canada. Historically, infections with infectious bursal disease virus (IBDV) and chicken anemia virus (CAV) have been known to suppress the immune system of broilers and make them more susceptible to a secondary disease such as IBH. Recently it has been reported that virulent adenoviruses are able to cause IBH as a primary disease in broilers without apparent involvement of IBDV and CAV. The objectives of this study were to examine the possible association of IBH with IBDV and CAV infections in Western Canada and to identify adenoviruses involved in outbreaks. Serum samples from 17 broiler-breeder flocks and their progeny were collected when broilers were hatched and then again from broilers at the time of slaughter, and these samples were tested for IBDV and CAV antibodies by enzyme-linked immunosorbent assay (ELISA). Based on the ELISA titers the antibody response to vaccination against IBDV and CAV was at an expected level in all broiler flocks. Therefore, IBH outbreaks in these flocks were not due to inadequate levels of antibodies against IBDV and CAV. Moreover, there was no correlation found between occurrences of IBH outbreaks in broilers and their IBDV or CAV titers at the time of processing. Viruses that were isolated from livers of birds suffering from IBH could be classified into four different genotypes. Their hexon gene loop 1 sequences showed high percentages of identity to FAdV-7, FAdV-8a, FAdV-8b, and FAdV-11. The results of this study could not demonstrate an association of IBH with IBDV and CAV infections, but they supported the hypothesis that IBH in broilers in Western Canada is a primary disease with no apparent immunosuppressive involvement.     

Characterization of adaptive immune responses induced by a new genetically inactivated Salmonella Enteritidis vaccine

The superior conservation of antigenic determinants on the surface of genetically inactivated bacterial ghosts makes them attractive immunogenic inactivated vaccine candidates. The efficacy of Salmonella Enteritidis (SE) ghost vaccination was evaluated in chickens by characterizing the nature of the adaptive immune response. Chickens from the immunized group demonstrated significant increases in SE-specific plasma IgG, intestinal secretory IgA, and lymphocyte proliferative response. The populations of CD4, CD8, and TCR γδ T-cells in immunized chickens were significantly greater than in the controls. Increased levels of IFN-γ, IL-2, IL-6 and IL-10 were observed in peripheral blood mononuclear cells stimulated with SE specific antigen. After virulent SE challenge, the immune system of immunized chickens was rapidly stimulated, as indicated by significantly increased population of CD4 and CD8 T-cells. Furthermore, the immunized group exhibited decreased challenge strain recovery of the internal organs compared to the non-immunized group. Together, these data indicate that the immunization induced humoral and cell-mediated immunity might be responsible for significant reduction of the virulent challenge strain load in the internal organs of immunized chickens.     

Baculovirus virions displaying infectious bursal disease virus VP2 protein protect chickens against infectious bursal disease virus infection

Infectious bursal disease (IBD) is an acute and contagious viral infection of young chickens caused by IBD virus (IBDV). The VP2 protein of IBDV is the only antigen for inducing neutralizing antibodies and protective immunity in the natural host. In the current study, we have succeeded in construction of one recombinant baculovirus BacSC-VP2 expressing His6-tagged VP2 with the baculovirus envelope protein gp64 transmembrane domain (TM) and cytoplasmic domain (CTD). The His6-tagged recombinant VP2 was expressed and anchored on the plasma membrane of Sf-9 cells, as examined by western blot and confocal microscopy. Immunogold electron microscopy demonstrated that the VP2 protein of IBDV was successfully displayed on the viral surface. Vaccination of chickens with the VP2-pseudotyped baculovirus vaccine (BacSC-VP2) elicited significantly higher levels of VP2-specific enzyme-linked immunosorbent assay antibodies and neutralizing antibodies than the control groups. IBDV-specific proliferation of lymphocytes was observed in chickens immunized with the recombinant BacSC-VP2. An in vivo challenge study of the recombinant baculovirus BacSC-VP2 showed effective protection against a very virulent (vv) IBDV infection in chickens. In addition, mortality and gross and histopathological findings in the bursa demonstrated the efficacy of the vaccine in reducing virulence of the disease. These results indicate that the recombinant baculovirus BacSC-VP2 can be a potential vaccine against IBDV infections.     

Protective efficacy of intermediate and intermediate plus infectious bursal disease virus (IBDV) vaccines against very virulent IBDV in commercial broilers

The evolution of very virulent (vv) infectious bursal disease virus (IBDV) has led to significant economic losses in many poultry-producing areas. Despite vigorous vaccination strategies, IBDV has been difficult to control. The protective efficacy of IBDV vaccines is traditionally evaluated in specific pathogen-free (SPF) chickens. But under field conditions, residual maternal antibody (mAb) levels may interfere with vaccine efficacy. In this study, commercial broilers with various levels of maternally derived antibodies were vaccinated with IBDV vaccines of different virulence (vaccines 1-3, intermediate; vaccine 4, intermediate plus). At an average maternal virus-neutralizing antibody (mAb) level of log2 10.8 (range 7.6-11.6) at day of vaccination, only the intermediate plus vaccine induced IBDV antibodies after 18 days, while the other intermediate vaccines did not. At average mAb levels of log2 6.7 (range 5.6-8.6) at day of vaccination, all vaccines induced circulating antibodies, although the onset of antibody production differed significantly between strains (P < 0.05). While the intermediate plus vaccine induced enzyme-linked immunosorbent assay antibody levels already at 14 days postvaccination (PV), the intermediate vaccines induced significant antibody levels 28 (vaccines 1, 2) and 35 (vaccine 3) days PV. The time of IBDV antibody induction correlated with the onset of bursa lesions. The severity of lesions was comparable between vaccines 1, 3, and 4 (lesion score 4), while vaccine 2 induce only mild lesions of score 1 in 23% of the tested birds. Despite the induction of antibodies, none of the tested vaccines fully protected against challenge with vvIBDV. All challenged birds had either significantly higher bursal lesion scores or a higher IBDV antigen load in the bursa or sometimes both in comparison with nonchallenged birds (P < 0.05). Our study demonstrates that the evaluation of IBDV-vaccine efficacy is difficult in commercial broilers. For the first time, it was shown that the onset of bursa lesions and recovery of IBDV-vaccinated broilers is delayed in the presence of mAb in comparison with SPF chickens but not suppressed as previously assumed. At the time of challenge, vaccinated birds may still have significant bursa lesions and may lack target cells for IBDV-challenge virus. To be able to evaluate vaccine efficacy in commercial broilers, parameters such as intrabursal IBDV-antigen load should also be considered in conjunction with bursa lesion scores.     

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。     

鸡传染性法氏囊病病毒地方流行毒株的免疫原性

从河北省一些发病鸡场分离到JD1～JD10共10株鸡传染性法氏囊病病毒(IBDV)毒株,用IBD标准阳性血清以琼扩试验进行了初步鉴定.并进行了IBDV分离物及其鸡胚适应毒免疫原对标准强毒IBDV-BC6/85株免疫保护试验,D78弱毒疫苗对IBDV各分离毒株的免疫保护试验以及分离毒株间交互免疫保护试验.结果表明,D78疫苗对JD2,JD5和JD10 IBDV分离株的保护率较低,分别为40%、50%和60%.分离毒株JD5、JD2及其鸡胚传代物E-JD2对强毒株的免疫保护率可达100%.交互免疫保护试验表明,JD2对其余各分离株的免疫保护指数达到80%以上,对标准强毒株和地方分离株均可产生有效免疫保护.     

紫锥菊对传染性法氏囊疫苗免疫效果的影响

为了探讨紫锥菊作为免疫增强剂的免疫效果和机理,本试验用1日龄的罗斯308肉鸡作为试验材料并用传染性法氏囊疫苗进行免疫。紫锥菊提取物分3种剂量组(A组0.1 mL/只、B组0.5 mL/只、C组1 mL/只)在6日龄开始连续给雏鸡口服7 d,在13,20,27,34,41日龄采血检测外周血中法氏囊病毒抗体,同时测定外周血中IL-2和TNF-α的含量,计算肉鸡的生产性能。结果表明,紫锥菊提取物能明显提高鸡外周血中法氏囊病毒抗体滴度,以及细胞因子IL-2和TNF-α含量,并能改善肉鸡的生产性能。所用3个剂量组中,以B组的0.5 mL/只为最佳的用药剂量。说明紫锥菊提取物具有明显的免疫促进作用。