鸡β-防御素-1对鸡传染性法氏囊病病毒VP2基因DNA疫苗的免疫佐剂作用

本文旨在研究鸡β-防御素-1(AvBD1)对鸡IBDVVP2基因DNA疫苗的免疫佐剂作用。通过基因工程技术,构建真核表达质粒pcDNA3.1(+)-AvBD1与pcDNA3.1(+)-VP2。14日龄岭南黄肉鸡随机分成5组,分别免疫PBS、空质粒载体pcDNA3.1(+)、重组质粒pcDNA3.1(+)-VP2、重组质粒pcDNA3.1(+)-AvBD1与pcD-NA3.1(+)-VP2联合免疫、IBD弱毒苗。收集免疫后不同时期的外周血血清样本,用ELISA方法检测血清中IB-DV VP2特异性抗体水平,通过流式细胞仪检测CD3+、CD4+与CD8+T淋巴细胞的含量。结果表明,联合免疫组(即pcDNA3.1(+)-AvBD1与pcDNA3.1(+)-VP2共同免疫)VP2特异性抗体水平显著高于其他组;单独免疫质粒pcDNA3.1(+)-VP2组VP2特异性抗体水平与免疫IBD弱毒苗组相当,显著高于PBS组与空质粒载体pcD-NA3.1(+)组。在二免后第7天,联合免疫组外周血中CD3+、CD4+与CD8+T淋巴细胞的含量也显著高于单独免疫质粒pcDNA3.1(+)-VP2组,其它时间无显著性差异。IBDV攻毒...     

IBDV VP2与Gallus Akirin2真核双表达载体的构建及应用

为提高传染性法氏囊病(IBD)VP2DNA疫苗的免疫效力,将优化合成的IBDV VP2与Gallus Akirin2串联基因定向克隆至真核表达载体pTriEx-4,获得重组质粒pVP2-Akirin2。体外转染293T细胞,提取表达产物进行SDSPAGE和Western blot分析,结果显示:在58 000和35 000附近各有一蛋白条带,分别能与鸡IBD阳性血清和兔Akirin2多克隆抗体发生特异性反应。将pVP2-Akirin2与同期构建的pVP2对照质粒分别免疫SPF鸡,加强免疫2周后,攻IBDV BC6-85强毒,4d后统计保护率,并监测免疫过程中血清IBD抗体滴度和IBDV中和抗体滴度的动态变化,结果显示:SPF鸡二免后14d,pVP2-Akirin2组血清IBD抗体滴度和IBDV中和抗体滴度均极显著高于pVP2组(P<0.01),且对IBDV强毒株BC6-85攻击的保护率为75%,高于pVP2对照组(55%)。结果表明:Gallus Akirin2基因对IBD VP2DNA疫苗具有明显的免疫增强作用。     

细胞毒性T淋巴细胞相关抗原4增强传染性法氏囊病病毒VP2质粒DNA的免疫效应分析

为评价分子佐剂细胞毒性T淋巴细胞相关抗原4(CTLA-4)对IBDV VP2质粒DNA的免疫增强作用,试验采用重组质粒载体表达重组蛋白mLTA-VP2-CTLA-4和mLTA-CTLA-4,家兔毒性试验确定其安全性,后选择10日龄非免疫健康鸡进行随机分组试验,设不同剂量mLTA-CTLA-4加IBD活疫苗免疫组、不同剂量mLTAVP2-CTLA-4免疫组、IBD活疫苗免疫组及空白对照组,免疫后用ELISA法定期检测鸡血清抗体IgG及小肠黏膜抗体IgA效价;鸡在加强免疫后用IBDV野生毒株攻击,连续观察2周并计算保护率。结果显示,mLTA-VP2-CTLA-4免疫组、mLTA-CTLA-4加活疫苗共同免疫组产生的IgG和IgA抗体水平与活疫苗免疫组无明显差别,mLTA-CTLA-4加活疫苗共同免疫组产生的IgG和IgA抗体水平略高于mLTA-VP2-CTLA-4免疫组,疫苗对鸡的保护率为100%。结果表明,构建的IBDV分子佐剂DNA疫苗载体能表达无毒性的重组蛋白质,并能产生很好的免疫保护率,为进一步研究IBD亚单位疫苗奠定基础。     

鸡Akirin2和GM-CSF促进传染性法氏囊病病毒VP2基因DNA疫苗免疫效果的研究

为提高鸡传染性法氏囊病病毒VP2基因DNA疫苗的免疫效力,将IBDV VP2、鸡Akirin2和鸡GM-CSF三基因编码区串联后克隆到真核表达载体pTriEx-4上,用构建的pT-VP2-Akirin2-GM-CSF重组质粒体外转染293T细胞,然后提取表达产物进行SDS-PAGE分析。结果在58、35、22ku附近各有一蛋白条带。用pT-VP2-Akirin2-GM-CSF免疫SPF鸡,加强免疫2周后,攻IBDV BC6-85强毒,4d后统计保护率。结果发现,注射14d后,pT-VP2-Akirin2-GM-CSF质粒免疫组血清中能检测到特异性IBDV抗体和IBDV中和抗体,第28天,该组鸡的抗体滴度极显著高于空白对照组(P0.01),该组鸡外周血淋巴细胞增殖能力也极显著高于空白对照组(P0.01)。说明VP2-Akirin2-GM-CSF三基因串联DNA疫苗有很好的应用前景。     

人参皂苷Rg1-菌体CpG对IBDV VP2基因重组真核表达质粒免疫效果的影响

将构建的含鸡传染性法氏囊病病毒（IBDV）JS超强毒株VP2基因的重组真核表达质粒与人参皂苷Rg1和CpG DNA联合佐剂免疫SPF鸡,检测免疫后的抗体水平,并观察超强毒株攻毒后的免疫保护效果。试验结果显示：Rg1-CpG佐剂与重组真核表达质粒DNA疫苗联合免疫后的抗体水平比单一使用DNA疫苗高,二者间有显著性差异;Rg1-CpG佐剂组的发病率、死亡率均低于非佐剂组,保护率则高于非佐剂组,且有显著性差异;而与法氏囊病中等毒力（NF8株）活疫苗免疫组的抗体水平及保护率相一致。表明Rg1-CpG佐剂显著增强了IBDV DNA疫苗的免疫效果。     

霍乱弧菌封闭带毒素功能片段△G的原核表达及其免疫增强活性

用PCR扩增了MBP—ZOT质粒上的ZOT基因，该基因编码264～399位氨基酸残基C末端的15ku △G片段，并与经改造后的质粒P^BCX、连接。将重组后的质粒PMLAG在大肠杆菌BL21中表达，将表达的目的蛋白纯化，再将p^BCX-△G片段与传染性腔上囊炎病毒VP2包涵体蛋白通过滴鼻免疫途径对14日龄SPF鸡进行联合免疫试验，分别于免疫后第10、20d采集血清样品，进行ELISA试验，检测免疫后IBD抗体效价。动物免疫试验发现：融合蛋白P^BCX △G起到了明显免疫增强效果，与VP2重组蛋白联合免疫2次后，血清IBD的VP2 IgG抗体效价是单独用VP2免疫组的3倍，明显高于空白免疫组。     

两种鸡传染性法氏囊病疫苗免疫1日龄商品肉鸡的效果比较

将IBD抗原抗体复合物疫苗(囊胚宝)和含IBDV VP2蛋白的亚单位灭活疫苗(新流法)免疫1日龄商品肉鸡,对其免疫效果进行了比较。抗体检测结果表明,利用经典IBD试剂盒检测时,囊胚宝免疫组35日龄和42日龄的ELISA抗体水平高于新流法免疫组;利用VP2专用试剂盒检测时,新流法组28日龄ELISA抗体水平高于囊胚宝组,35日龄时则是囊胚宝组抗体水平较高。于28日龄时利用IBDV超强毒株(vvIBDV)进行攻毒结果表明,攻毒后第4天,新流法免疫组的腔上囊大部分呈现出明显病变,且9/10的腔上囊中检出vvIBDV;囊胚宝免疫组鸡腔上囊则10/10仅检出W2512株疫苗毒。攻毒后4 d增重对比结果显示:囊胚宝免疫组鸡增重明显高于新流法免疫组和未免疫组。本试验结果表明,雏鸡通过1日龄免疫囊胚宝来预防IBD的效果要优于本试验中所用的新流法灭活疫苗。     

传染性法氏囊病病毒主要结构蛋白VP2、VP1和VP2-VP1串联基因的原核表达及其初步应用

为获得传染性法氏囊病病毒(IBDV)特异性抗体检测用抗原VP2、VP1及VP2-VP1蛋白,分别设计引物扩增IBDV野毒株NN1172的VP2和VP1基因,并扩增VP2和VP1基因中抗原性和亲水性较好的重要区域,通过PCR扩增基因串联方法对截短的VP2和截短的VP1基因进行串联,首次获得VP2-VP1串联基因,并对VP2、VP1和VP2-VP1串联基因进行了原核表达和鉴定。结果成功构建了原核表达载体pET-VP2、pET-VP1和pET-VP2-VP1;诱导表达条件显示,3个重组质粒分别转入BL21菌株后经0.05 mmol/L IPTG诱导表达,分别得到分子量为69、114和63 kDa的VP2、VP1和VP2-VP1重组蛋白,且均以包涵体形式表达,3个重组蛋白分别于诱导后5、3和6 h时表达量最多。Western blot结果显示,表达的VP2、VP1和VP2-VP1蛋白与鸡抗IBDV阳性血清均具有良好的反应原性。以纯化的VP2、VP1和VP2-VP1蛋白作为包被抗原对传染性支气管炎病毒(IBV)、呼肠孤病毒(ReoV)、禽白血病病毒(ALV)和新城疫病毒(NDV)4种阳性血清检测均为阴性,表明所获得的纯化蛋白具有高度的特异性;对免疫了IBD灭活疫苗,IBD基因工程疫苗和IBD弱毒疫苗的商业鸡群进行抗体检测,结果均能显示疫苗免疫后机体抗体水平的变化趋势。本研究表明利用该原核表达系统所表达的3个蛋白均具有良好的免疫反应活性,为IBDV特异性抗体的检测和新型亚单位疫苗的研发奠定基础。     

鸡传染性法氏囊病病毒超强株VP2基因重组新城疫病毒胚胎免疫安全性及效力试验

为研制能够同时预防传染性法氏囊病(IBD)和新城疫(ND)的疫苗,本研究选用表达IBD病毒(IBDV)超强毒株(vvIBDV)VP2基因的重组ND病毒(NDV)LaSota疫苗株(rL-VP2),测定其半数鸡胚感染量、平均鸡胚致死时间、脑内接种指数和静脉内致病指数等指标,按不同剂量接种18胚龄SPF鸡胚,分别于出雏后第9d、第14d和第21d采血,用微量凝集法和ELISA方法测定血清中抗NDV抗体和抗IBDV抗体水平,并于出雏后28d用NDV强毒(F48E9株)和vvIBDVGx株攻毒,评估重组疫苗的胚胎免疫效果。结果显示:按104EID50/枚剂量进行免疫不会影响SPF鸡胚出雏率和出雏后21d存活率,并且该免疫组雏鸡能够对NDV强毒和vvIBDV攻毒提供安全的免疫保护。     

传染性法氏囊病病毒VP2基因真核细胞表达载体的构建及免疫应用研究

应用DNA重组技术将含有IBDV保护性抗原VP2质粒，以EcoRI、xhoI酶切，将酶切得到的VP2基因移入到载体pcDNA3CMV启动子下游，得到含有IBDV VP2基因的真核表达载体pcD-VP2基因疫苗。pcDVP2体外转染细胞能正确表达目的的蛋白，免疫雏鸡后20d，在体内可检测到特异性抗体。     

DNA immunization against very virulent infectious bursal disease virus with VP2-4-3 gene and chicken IL-6 gene

The present study was to investigate the feasibility and efficiency of the DNA vaccine to protect chickens against very virulent infectious bursal disease virus (vvIBDV) infection. A plasmid DNA carrying VP2-4-3 genes of vvIBDV SH95 and a plasmid DNA carrying chicken interleukin-6 (ChIL-6) genes were constructed and designated as pALTER-MAX-VP2-4-3 and pALTER-MAX-ChIL-6 respectively. Several DNA vaccination experiments were performed: 1-week-old chickens were intramuscularly injected with only plasmid pcDNA3-VP2, pALTER-MAX-VP2-4-3 or mixture with pALTER-MAX-ChIL-6. The chickens at 4 weeks old were orally inoculated with vvIBDV SH95. The results showed that immunization with the mixture of pALTER-MAX-VP2-4-3 and pALTER-MAX-ChIL-6 three times conferred protection for 90% of chickens. Enzyme-linked immunosorbent assay (ELISA) antibody titres in chickens immunized together with pALTER-MAX-ChIL-6 were higher than those immunized simply with plasmid pcDNA3-VP2 or pALTER-MAX-VP2-4-3. IBDV was not detected in the bursa of the protected chickens at 8 days after challenge by RT-PCR. The results indicate that protection against vvIBDV can be achieved by using the VP2-4-3 gene of vvIBDV as a DNA vaccine. Furthermore, the simultaneous injection of ChIL-6 plasmid significantly increased the protection after challenge with the very virulent strain.     

Protection of chicken against very virulent IBDV provided by in ovo priming with DNA vaccine and boosting with killed vaccine and the adjuvant effects of plasmid-encoded chicken interleukin-2 and interferon-��

The aim of this study was to examine the efficacy of in ovo prime-boost vaccination against infectious bursal disease virus (IBDV) using a DNA vaccine to prime in ovo followed by a killed-vaccine boost post hatching. In addition, the adjuvant effects of plasmid-encoded chicken interleukin-2 and chicken interferon-γ were tested in conjunction with the vaccine. A plasmid DNA vaccine (pcDNA-VP243) encoding the VP2, VP4, and VP3 proteins of the very virulent IBDV (vvIBDV) SH/92 strain was injected into the amniotic sac alone or in combination with a plasmid encoding chicken IL-2 (ChIL-2) or chicken IFN-γ (ChIFN-γ) at embryonation day 18, followed by an intramuscular injection of a commercial killed IBD vaccine at 1 week of age. The chickens were orally challenged with the vvIBDV SH/92 strain at 3 weeks of age and observed for 10 days. In ovo DNA immunization followed by a killed-vaccine boost provided significantly better immunity than the other options. No mortality was observed in this group after a challenge with the vvIBDV. The prime-boost strategy was moderately effective against bursal damage, which was measured by the bursa weight/body weight ratio, the presence of IBDV RNA, and the bursal lesion score. In ovo DNA vaccination with no boost did not provide sufficient immunity, and the addition of ChIL-2 or ChIFN-γ did not enhance protective immunity. In the ConA-induced lymphocyte proliferation assay of peripheral blood lymphocyte collected 10 days post-challenge, there was greater proliferation responses in the DNA vaccine plus boost and DNA vaccine with ChIL-2 plus boost groups compared to the other groups. These findings suggest that priming with DNA vaccine and boosting with killed vaccine is an effective strategy for protecting chickens against vvIBDV.     

表达鸡传染性法氏囊病病毒VP2基因的重组火鸡疱疹病毒的构建及生物学特性分析

鸡传染性法氏囊病（IBD）是一种严重危害养禽业的高度致死性和免疫抑制性传染病。为研制IBD重组火鸡疱疹病毒（HVT）活载体疫苗,本研究构建了表达鸡传染性法氏囊病病毒（IBDV）保护性抗原VP2基因的重组HVT并对其体外生物学特性进行了分析。通过RT-PCR扩增IBDV超强毒株VP2基因并克隆入pCI载体,获得重组真核表达质粒pCI-VP2。用限制性内切酶将携带CMV启动子的VP2基因表达框架切下,连接于入门质粒pENTR,构建获得重组入门质粒pENTR-VP2。将pENTR-VP2与HVT重组黏粒H3-Kan/ccdB进行LR重组反应,构建重组表达黏粒H3-VP2。用H3-VP2与其他4个相互重叠并覆盖HVT全基因组的黏粒共同转染鸡胚成纤维细胞（CEF）,拯救获得重组病毒rHVT-VP2。将重组病毒在CEF中连续传至20代后用PCR、间接免疫荧光试验和免疫印迹试验进行检测,并绘制重组病毒体外生长曲线,分析其体外复制特性。结果表明,重组病毒rHVT-VP2能够稳定表达VP2蛋白,rHVT-VP2在CEF中的复制能力与亲本病毒无明显差异。重组病毒rHVT-VP2免疫鸡后能够诱导产生IBDV中和抗体,并对IBDV强毒株攻击引起的死亡提供90%免疫保护。重组病毒rHVT-VP2的构建为研制IBD重组HVT活载体疫苗奠定了基础,对IBD的防控具有重要意义。     

DNA Immunization Against Very Virulent Infectious Bursal Disease Virus with VP2‐4‐3 Gene and Chicken IL‐6 Gene

The present study was to investigate the feasibility and efficiency of the DNA vaccine to protect chickens against very virulent infectious bursal disease virus (vvIBDV) infection. A plasmid DNA carrying VP2‐4‐3 genes of vvIBDV SH95 and a plasmid DNA carrying chicken interleukin‐6 (ChIL‐6) genes were constructed and designated as pALTER‐MAX‐VP2‐4‐3 and pALTER‐MAX‐ChIL‐6 respectively. Several DNA vaccination experiments were performed: 1‐week‐old chickens were intramuscularly injected with only plasmid pcDNA3‐VP2, pALTER‐MAX‐VP2‐4‐3 or mixture with pALTER‐MAX‐ChIL‐6. The chickens at 4 weeks old were orally inoculated with vvIBDV SH95. The results showed that immunization with the mixture of pALTER‐MAX‐VP2‐4‐3 and pALTER‐MAX‐ChIL‐6 three times conferred protection for 90% of chickens. Enzyme‐linked immunosorbent assay (ELISA) antibody titres in chickens immunized together with pALTER‐MAX‐ChIL‐6 were higher than those immunized simply with plasmid pcDNA3‐VP2 or pALTER‐MAX‐VP2‐4‐3. IBDV was not detected in the bursa of the protected chickens at 8 days after challenge by RT‐PCR. The results indicate that protection against vvIBDV can be achieved by using the VP2‐4‐3 gene of vvIBDV as a DNA vaccine. Furthermore, the simultaneous injection of ChIL‐6 plasmid significantly increased the protection after challenge with the very virulent strain.     

Infectious bursal disease virus variant from commercial Leghorn pullets

An infectious bursal disease virus (IBDV) was isolated from 39-to-43-day-old commercial leghorn pullets suspected of having infectious bursal disease (IBD). These chickens had been vaccinated with a commercial live IBDV vaccine at 28 and 35 days of age. An isolate designated IN was recovered using specific-pathogen-free (SPF) chickens and the BGM-70 established cell line. Experimental studies using SPF chickens vaccinated with either inactivated vaccines made from the vaccine strain used in the problem flock or a standard-type vaccine indicated no protection against the IN isolate. However, two variants and another standard-type vaccine induced protection against the IN isolate. Cross-neutralization tests indicated that the IN isolate differed antigenically from commercial vaccine strains and was related to the variant IBDV strains recently isolated from broilers. To our knowledge, this is the first report of a variant IBDV recovered from commercial layer chickens in the United States.     

免疫增强剂对IBD疫苗免疫雏鸡局部黏膜免疫功能的影响

分别将免疫增强剂“禽福”和“Inmunair”与鸡传染性法氏囊病（IBD）中等毒力活疫苗配合使用,检测免疫雏鸡哈德尔氏腺和盲肠扁桃体T细胞及IgA、IgM和IgG抗体生成细胞数量。泪液、气管液、胆汁、肠液中免疫球蛋白IgG、IgM、IgA含量的动态变化,结果发现,应用免疫增强剂IBD疫苗免疫雏鸡上述局部免疫组织及四种局部体液的相应各项免疫检测指标均较IBD疫苗单独免疫雏鸡不同程度地增高,表明免疫增强剂与疫苗联合应用,能显著提高疫苗免疫雏鸡眼部、呼吸道和消化道局部黏膜免疫功能;而IBD强毒攻击后,疫苗单独免疫雏鸡上述指标明显低于应用免疫增强剂的疫苗免疫雏鸡,同时。后者对IBD强毒攻击的有效抵抗力明显高于前者。     

Adjuvant activity of chicken interleukin-12 co-administered with infectious bursal disease virus recombinant VP2 antigen in chickens

A recombinant fowlpox virus (rFPV/VP2) expressing infectious bursal diseases virus (IBDV) VP2 gene has been constructed. After purification and identification of rFPV/VP2, the adjuvant activity of the recombinant chicken IL-12 (rchIL-12), synthesized by our previous construct of rFPV/chIL-12, in rFPV/VP2-expressed rVP2 antigen was assessed in one-week-old specific-pathogen free chickens. The results indicated that rchIL-12 alone or rchIL-12 plus mineral oil (MO) co-administered with rVP2 antigen significantly enhanced the production of serum neutralization (SN) antibody against IBDV, compared to those with MO alone. The SN titers in groups receiving rVP2 antigen with MO alone were more inconsistent after vaccination. On the other hand, rchIL-12 significantly stimulated IFN-γ production in serum and in splenocyte cultured supernatant, suggesting that rchIL-12 alone or plus MO significantly induced a cell-mediated immune response. Finally, bursal lesion protection from very virulent IBDV (vvIBDV) challenge in chickens receiving rVP2 antigen with rchIL-12 alone or plus MO was much more effective than that with MO alone at two weeks after boosting. Taken together, rchIL-12 alone augmented in vivo the induction of a primary and also a secondary SN antibody production and a cell-mediated immunity against IBDV rVP2 antigen, which conferred the enhancement of bursal lesion protective efficacy from vvIBDV challenge. These data indicated that a potential for chIL-12 as immunoadjuvant for chicken vaccine development such as IBDV rVP2 antigen.     

Effects of DDA, CpG-ODN, and plasmid-encoded chicken IFN-�� on protective immunity by a DNA vaccine against IBDV in chickens

This study examined the adjuvant effects of dimethyl dioctadecyl ammonium bromide (DDA), CpG oligodeoxynucleotides (CpG-ODN), and chicken interferon-γ (ChIFN-γ) on a DNA vaccine (pcDNA-VP243) against the infectious bursal disease virus (IBDV). A plasmid encoding chicken IFN-ã was constructed. Twice at 2-week intervals, two-week-old chickens were injected intramuscularly and intraperitoneally with either a DNA vaccine alone or a DNA vaccine together with the respective adjuvants. On week 2 after the second immunization, the chickens were orally challenged with the highly virulent IBDV. The groups that received the DNA vaccines plus either DDA or CpG-ODN showed significantly lower survival rates than the group that received the DNA vaccine alone. However, the survival rates for the DNA vaccine alone and for the DNA vaccine plus ChIFN-γ were similar. The chickens had no detectable antibodies to the IBDV before the challenge but all the surviving chickens in all groups except for the normal control group showed the induction of antibodies to the IBDV at day 10 after the challenge. As judged by the lymphocyte proliferation assays using the a WST-8 solution performed on the peripheral blood and splenic lymphocytes, the stimulation indices (SI) of the peripheral blood lymphocytes in all groups except for the normal control group were similar immediately before the challenge. At 10 days post-challenge, the SI for DNA vaccine plus either CpG-ODN or ChIFN-γ was similar to that of the DNA vaccine control group. For splenic lymphocytes, the SI in the DNA vaccine plus CpG-ODN and DNA vaccine plus ChIFN-γ groups were higher than for the DNA vaccine control. These results suggest that DDA actually compromises the protection against the IBDV by DNA vaccine, and CpG-ODN and IFN-γ had no significant effect.