鸡传染性支气管炎强毒分离株遗传进化分析和免疫保护试验

从山东省发病鸡群中分离鉴定了一株鸡传染性支气管炎病毒（Infectious bronchitis virus,IBV）强毒株SDIB821/2012,对其进行S1基因序列测定分析和免疫保护试验。S1基因遗传进化分析结果显示,SDIB821/2012属于以QXIBV为代表的基因型,与同属一个基因型的IBV参考株氨基酸同源性为91.6%～98.5%,与疫苗株491同源性为77.6%,与H120和MA5同源性均为74.8%。免疫保护试验结果显示,根据试验鸡临床症状和发病死亡情况,弱毒活疫苗491对SDIB821/2012的保护率为90%,而H120和MA5对SDIB821/2012的保护率分别仅为40%和33%。攻毒后各免疫组喉头、泄殖腔棉拭样品以及气管、肺脏和肾脏组织均可检测到病毒,表明3种IB疫苗均不能对SDIB821/2012提供完全的免疫保护。     

Genome analysis and development of infectious cDNA clone of a virulence-attenuated strain of foot-and-mouth disease virus type Asia 1 from China

The RNA genome sequence of the rabbit passage-attenuated strain of foot-and-mouth disease virus (FMDV) Asia 1, ZB/CHA/58(att), was determined to be 8165 nt in length excluding the poly(C) tract in the 5′ UTR and the poly(A) tail at the 3′ end. ZB/CHA/58(att) was most similar to the vaccine strain Asia 1/YNBS/58 in genome sequence and there were no deletions or insertions within the deduced polyprotein between ZB/CHA/58(att) and YNBS/58, but there were a total of 25 substitutions at the amino acid level and an extra 19-nt stretch in the 5′ UTR was found in ZB/CHA/58(att). An infectious full-length cDNA clone of ZB/CHA/58(att) was developed. Infectious virus could be recovered in BHK-21 cells transfected with the synthetic viral RNA transcribed in vitro. The plaque morphology, growth kinetics and antigenic profile of the infectious clone-derived virus (termed tZB) were indistinguishable from those induced by the parental virus. Furthermore, the virulence properties of ZB/CHA/58(att) and tZB were found to be highly similar in the mouse model. The availability of genome sequence information and infectious cDNA clone of the FMDV ZB/CHA/58(att) lays a new ground for further investigation of FMDV virulence determinants and development of new potent vaccine to FMD.     

Identification of field isolates of infectious bronchitis virus by interference with the La Sota of strain of Newcastle disease virus

The interference phenomenon of infectious bronchitis virus (IBV) with growth of Newcastle disease virus (NDV) in embryonating chicken eggs (ECE) was used as a diagnostic method. Fifteen field isolates obtained from presumptively infectious-bronchitis-affected chickens were analyzed by the IBV-NDV interference test. Eight isolates were capable of interfering with the growth of the La Sota strain of NDV, as measured by hemagglutination (HA) activity when IBV was inoculated 10 hr before NDV into ECE. The interference was considered specific for IBV, because it could be eliminated by adding homologous anti-IBV serum. The sensibility of this method could be demonstrated, because in some cases low-passage levels of IBV isolates showing HA interference ability were not capable of producing lesions in ECE. Furthermore, serologically negative IBV samples did not interfere with NDV growth. From these results, the IBV-NDV interference test appears to be a potential diagnostic alternative for identifying IBV field isolates.     

几种病毒与禽病原性大肠杆菌的人工联合感染

以2种剂量的低致病性禽流感病毒(lowly pathogenic avian influenza virus,LPAIV)，传染性支气管炎病毒（infectious bronchitis virus,IBV)疫苗株H120和H52，新城疫病毒（Newcastle disese viurs,NDV)Lasota株分别于气管内注射10日龄易感鸡，2d后，气管注射禽病原性大肠杆菌O37株（O78），连续观察5d，结果，除LPAIV单独感染组有6．25％的死亡率外，其余各病毒单独接种组均健活；大肠杆菌O37株单独接种组的死亡率为62．50％，较高剂量的LPAIV，IBV H120和H52，NDV Lasota株与大肠杆菌O37株有效强的协同致病作用，死亡率分别达到81.25%,100.00%,93.75%和87.50%，而较低剂量的上述病毒则无明显的协同作用，IBV，NDV疫苗株与大肠杆菌联合接种组的多数死亡鸡病程推迟。     

Transmissibility of infectious bronchitis virus H120 vaccine strain among broilers under experimental conditions

The aim of this study was to quantify transmission of infectious bronchitis virus (IBV) H120 vaccine strain among broilers, and to assess whether birds that have been exposed to vaccine strain-shedding birds were protected against clinical signs after infection with a virulent strain of the same serotype. A transmission experiment and a replicate were carried out, each with six groups of commercial broilers. At day of hatch (n = 30) or at 15 days of age (n = 20), half of each group was inoculated with either IBV H120 vaccine (H120 group), virulent IBV M41 (M41 group), or were mock-infected, thereby contact-exposing the other half of each group. Nasal discharge was recorded, and antibody response and virus shedding were measured. To measure clinical protection, four weeks after inoculation all birds, in all groups, were challenged with IBV M41. The reproduction ratio (R; the average number of contact infections caused by one infectious bird) was determined to quantify virus transmission. All contact-exposed birds, except for one in an H120 group, became infected with either IBV H120 or IBV M41. Almost all birds contact-infected with IBV H120 or IBV M41 were subsequently protected against clinical signs after challenge with IBV M41. The lower limits of the 95% confidence interval (CI) of the R of IBV H120 vaccine, and of IBV M41, were significantly <1. For both IBV H120 and IBV M41, the 95% CI was [2.1-infinity] following inoculation at day of hatch and [1.8-infinity] after inoculation at 15 days of age. This finding demonstrates that IBV H120 vaccine is able to spread extensively among broilers. This implies that this vaccine strain might be able to become endemically present in the poultry population. It also implies that, even if not all birds received vaccine during spray application, due to the ability of the vaccine to spread in the flock, they will most likely be protected against clinical signs after a subsequent field virus infection.     

4株IBV中国地方分离株部分结构基因变异的研究

本研究通过RT-PCR分别获得了4个国内IBV分离株的S1、M和N基因，并进行了克隆及测序。序列分析结果表明：HaN2-95株的S1、M和N基因核苷酸序列均与IBV H120疫苗株的同源性最高；尽管HaN1-95株的S1基因与IBV H52疫苗株的亲缘关系最近，但是该毒株的M基因和N基因却与IBV Gray株的同源性最高；GX1-98株的S1和M基因均与IBV H52疫苗株的亲缘关系最近，但其N基因却与IBV Gray株和Ark99株有高度的同源性；GX2-98株的S1基因却与IBV Holte株的亲缘关系最近。上述结果提示国内有些IBV分离株的出现可能与疫苗株的使用有关。     

鸡传染性支气管炎病毒SC株N基因序列测定与同源性分析

从我国四川省一疑似鸡传染性支气管炎(Avianinfectious bronchitisvirus,IB)的雏鸡病料中成功分离到一株鸡传染性支气管炎病毒(Infectious Bronchitis Virus,IBV),命名为SC。病毒经鸡胚传代、血凝试验监测和负染电镜检查证实为IBV。自接毒鸡胚尿囊液中提取RNA后应用反转录-聚合酶链反应(RT-PCR)扩增得到了IBVSC株mRNA6 cDNA(编码N蛋白)。应用DNAstar5．06,Clustal1．8分析软件将克隆测序的N蛋白基因与Genbank中11株国内外参考毒株进行序列比较分析和同源性分析,发现IBV SC株变异独特,明显不同于国内外参考毒株。     

鸡传染性支气管炎病毒(IBV)干扰新城疫病毒(NDV)增殖现象的研究

ＩＢＶ毒株Ｈ１２０、Ｈ５２、ＭＡ５对ＮＤＶ－ＬａＳｏｔａ的干扰实验证明ＩＢＶ特异性干扰ＮＤＶ增殖。１）采取不同顺序的同胚接种法：ＩＢＶ接种之后再接种ＮＤＶ;或ＮＤＶ接种之后再接种ＩＢＶ,及ＩＢＶ,ＮＤＶ同时接种,ＩＢＶ均干扰ＮＤＶ的增殖。２）ＮＤＶ接种３６小时之内,干扰现象最为明显,Ｈ１２０,Ｈ５２的干扰能力稍强于ＭＡ５。３）ＮＤＶ血清中和实验结果显示,不同顺序同胚接种ＮＤＶ、ＩＢＶ时,ＮＤＶ－ＬａＳｏｔａ不影响ＩＢＶ的增殖能力。同胚增殖ＩＢＶ,ＮＤＶ的关键是控制ＮＤＶ、ＩＢＶ的接毒量及选择合适的收毒时间。     

Evaluation of the antigen relatedness and efficacy of a single vaccination with different infectious bronchitis virus strains against a challenge with Malaysian variant and QX-like IBV strains

BackgroundThe predominant infectious bronchitis virus (IBV) strains detected in chickens in Malaysia are the Malaysian variant (MV) and QX-like, which are associated with respiratory distress, nephropathy, and high mortality. On the other hand, the antigenic relatedness and efficacy of IBV vaccines against these 2 field IBV strains are not well characterized.ObjectivesThis study aimed to determine the antigen relatedness and efficacy of different IB vaccine strains against a challenge with MV and QX-like strains.MethodsThe antigen relatedness and the ability of different IB vaccine strains in conferring protection against MV and QX-like were assessed based on the clinical signs, macroscopic lesions, and ciliary activity.ResultsThe MV strain IBS037A/2014 showed minor antigenic subtype differences with the vaccine virus Mass H120 and 4/91 strains but showed major antigenic subtype differences with the K2 strain. The Malaysian QX-like strain IBS130/2015 showed major antigenic subtype differences with the MV strain IBS037A/2014 and the vaccine strains except for K2. Chickens vaccinated once with Mass (H120) or with non-Mass (4/91 and K2) developed antibody responses with the highest antibody titer detected in the groups vaccinated with H120 and 4/91. The mean ciliary activities of the vaccinated chickens were between 56 to 59% and 48 to 52% in chickens challenged with IBS037A/2014 and IBS130/2015, respectively. The vaccinated and challenged birds showed mild to severe lesions in the lungs and kidneys.ConclusionsDespite the minor antigenic subtype differences, a single inoculation with Mass or non-Mass vaccines could not protect against the MV IBS037A/2014 and QX-like IBS130/2015.     

Reversion to virulence of chicken-passaged infectious bronchitis vaccine virus

Serial passage of two infectious bronchitis virus (IBV) vaccine strains in chickens enhanced their capacity to increase the incidence and severity of Mycoplasma synoviae (MS) airsacculitis. Included in this report were the mild Massachusetts-type Connaught strain and the Arkansas 99 vaccine strain of IBV. The Connaught strain and one of two Ark 99 vaccine strains passaged in chickens increased the incidence of airsacculitis markedly compared with nonpassaged virus. The other Ark 99 vaccine virus already exacerbated MS airsacculitis, before passage in chickens, and its influence did not increase on passage. All IBV strains studied to date have either possessed this trait or reacquired it on passage in the natural host.     

鸡传染性支气管炎病毒HN99株S1基因的克隆与序列测定

根据基因库中收录的鸡传染性支气管炎病毒 (IBV)S1基因的序列 ,设计了一对引物并采用RT -PCR扩增了鸡传染性支气管炎病毒HN99株的S1基因 ,扩增产物进行了克隆、测序 ,获得了IBVHN99株S1基因片段 ,其大小为1 739bp(含前导序列 ) ,其核苷酸序列与H1 2 0、H52、M41、Gray、Holte的S1基因核苷酸序列同源性较低 ,分别为 79.1 %,79.2 %,77.3%,77.8%,79 .4%,有大量的点突变并伴有基因插入和缺失 ;IBVHN99株的S1基因推导的氨基酸与H1 2 0、H52、M41、Gray、Holte株氨基酸的同源性分别为80 .1 %,79.9%,79.5%,78.5%,78.5%,经S1基因系统进化分析 ,提示IBVHN99株与其它各毒株的亲缘关系较远 ,初步证实IBVHN99株为一新的IBV毒株     

从全长cDNA克隆恢复猪瘟病毒方法的研究

以携带猪瘟病毒Thiverval株全长cDNA克隆的pAC/F101/T1-7载体质粒为模板,在体外转录病毒基因组RNA,并转染PK-15和BHK-21细胞,通过传代、RT-PCR、免疫过氧化物酶细胞单层试验鉴定,成功地在两种细胞中拯救出具有感染性的病毒粒子。同时,通过2种细胞转染效率的对比试验,成功建立了利用高转染效率的其它真核细胞作为病毒拯救的过渡细胞,然后再在猪肾细胞系上进行增殖的病毒拯救方式,极大提高了猪瘟病毒拯救的效率。     

一株类4/91病毒的初步研究

从发病鸡群中分离到一株病毒，通过鸡胚接种、电镜观察、动物回归试验、气管环交叉中和试验等，初步确定为传染性支气管炎病毒，暂命名为A2。外源病原检查结果为阴性。攻毒试验：在气管、肾以及肌肉等组织均有明显的病变；病理组织观察；在气管、肾脏和肌肉均发生了一定程度的病理变化。利用电泳对传统的病毒株和分离株进行了病毒结构蛋白分析，A2株出现了31kD的特殊蛋白条带。气管环交叉中和试验表明A2株与4／91病毒为同一血清型；临床的动物免疫试验结果表明，4／91疫苗有较好的保护作用。     

鸡肾型IBV的分离及其N基因的克隆与测序

通过病毒形态学观察、血凝试验、病毒干扰实验、动物回归实验等分离鉴定了1株鸡肾型传染性支气管炎病毒.利用RT-PCR技术对分离毒株的N基因进行了扩增,经克隆、序列测定和分析,证实分离株为肾型IBV.     

表达猪瘟病毒E2蛋白重组猪繁殖与呼吸道综合征病毒的研究

为构建表达猪瘟病毒(CSFV)E2蛋白重组猪繁殖与呼吸道综合征病毒(PRRSV),本研究首先利用高致病性PRRSV弱毒疫苗HuN4-F112株的感染性分子克隆作为平台,构建了一个在nsp2区有缺失的感染性分子克隆,命名为pHuN4-F112-△480-620。以pHuN4-F112-△480-620作为载体,采用突变PCR的方法将CSFV的主要保护性抗原E2基因1 bp～9 99 bp,1 bp～600 bp,1 bp～330 bp及256 bp～330 bp基因片段分别插到nsp2中aa 480～aa 620位氨基酸缺失编码区域。结果显示,插入完整E2基因或较大E2基因片段的重组PRRSV cDNA质粒均未能拯救出病毒,只有插入较小的E2基因片段(256 bp～330 bp)的重组病毒cDNA质粒成功地拯救出了重组病毒rPRRSV-F112-E2(256-330),拯救的病毒能够在MARC-145细胞上引起明显的细胞病变,而且生长速度明显高于其亲本病毒,间接荧光检测表明该重组病毒能够表达外源基因。     

鸡传染性支气管炎病毒SX01株的分离鉴定及M基因序列分析

本试验通过鸡胚矮小试验、血凝试验和RT-PCR等方法,从华北地区某鸡场发生疑似肾型传染性支气管炎的发病鸡群分离了1株鸡传染性支气管炎病毒,命名为SX01株.结果显示该分离株能引起鸡胚典型的临床症状;经1%胰酶处理后的尿囊液可凝集鸡红细胞,而未处理的则无血凝活性;利用RT-PCR对分离株M基因序列测定分析结果显示,SX01株的M基因核苷酸序列与GX-GL分离株同源性高达99.4%,与QX基因型毒株SDZB0808核苷酸同源性高达99.1%,与H120株同源性仅为90.0%,与BJ/00/02株M基因核苷酸同源性较低,为90.6%.遗传进化分析结果显示,该分离株与中国地方型分离株(GX-GL、SDZB0808、CK/CH/LJL/110302、DY07、IBVSX7)亲缘关系较近,位于同一进化分支;与H120代表的Mass型疫苗株的亲缘关系较远,是一株肾型传染性支气管炎病毒毒株.     

鸡传染性支气管炎病毒血凝抑制试验抗原的研制

为应用血凝抑制(HI)试验检验鸡传染性支气管炎疫苗免疫效力(血清、卵黄抗体水平),建立了鸡传染性支气管炎病毒HI试验抗原的制备方法。该方法是通过选取抗原谱最广的鸡传染性支气管炎病毒(IBV)M41株,经SPF鸡胚增殖培养36h后无菌收取鸡胚尿囊液,4℃、12 000r/min离心10min,上清用聚乙二醇(PEG)20000浓缩100倍;兔源A型产气荚膜梭菌中国标准株(C57-1株)37℃增殖培养18h,4℃、12 000r/min离心10min取上清,经PEG 20000透析袋浓缩5倍后通过0.20μm滤膜过滤除菌,然后将IBV液和A型产气荚膜梭菌菌液(含α毒素)二者按一定比例混合后经37℃恒温振荡感作2h,4℃经48h后制成。经大量试验表明,制备的IBV HI试验抗原效价高、稳定性好,可替代进口抗原应用于鸡群IBV疫苗免疫后血清抗体及卵黄抗体的HI效价检测。     

新城疫病毒LaSotaC5株感染性克隆的构建及病毒拯救

将本实验室保存的一株LaSota病毒用有限稀释法接种鸡胚进行纯化,连续传代5次后筛选到1株高血凝效价的纯培养克隆株,命名为LaSotaC5,并对其进行全基因组测序,克隆株与亲本株在生物学特性与基因序列上都存在一定的差异。参照LaSotaC5株全基因序列单酶切位点,用RT-PCR的方法将基因组分8段扩增,按照病毒基因组的结构顺序,将克隆片段定向插入到TVT转录载体中,成功构建含有病毒全长eDNA的转录载体TVT．LaSotaC5。将TVT-LaSotaC5与辅助质粒pCI-NP、pCI-P和pCI—L共转染BSR—T7／5细胞,成功拯救出了具有感染性的LaSota株新城疫病毒。病毒的成功拯救为后续基因功能和疫苗载体开发等方面的研究提供了平台。     

鸡传染性支气管炎病毒免疫机制和免疫预防研究进展

由鸡传染性支气管炎病毒（Infectious bronchitis virus,IBV）引起的鸡传染性支气管炎（Infectious bronchitis,IB）是高度传染的全球性鸡病之一,严重危害养鸡业。IBV众多的血清型及其基因组的不断变异,给IB的免疫防控带来很大的困难。IBV主要侵害鸡的呼吸系统、泌尿生殖系统和消化系统,病鸡出现呼吸困难、产蛋下降、肾炎和腺胃炎等症状和病变。IBV的特点是变异频繁,血清型复杂,所致疾病的临床表现差异很大。因此,IB已成为养禽业最难控制的疫病之一。鸡对IBV的免疫机制是国内外研究的热点之一。传统疫苗已不能完全保护免疫鸡群,开发IBV基因工程疫苗,从主要免疫原性蛋白的良好表达到免疫策略的不断完善,已成为未来预防IB的趋势。     

鸡传染支气管炎病毒H52、H120和M41株的PCR鉴别方法研究

根据GenBank发表的序列,对鸡传染性支气管炎病毒（IBV）H52、H120和M41株全基因组序列进行比较,设计并合成了两对特异性引物,其中一对引物能以M41株为模板,特异性扩增出1791bp的目的片断,从而特异鉴定IBVM41株;另一对引物能以H52株和H120株为模板,特异性扩增1700bp的目的片断,再用限制性内切酶NaeI对PCR产物进行酶切,H120株能够被切成1000bp和700bp两个片段,而H52株的PCR产物不存在该酶切位点,从而能区分H52株和H120株。本研究建立的PCR方法和技术具有快速、简单、特异性强等优点,可用于IBVH52、H120和M41株活疫苗的分子鉴别。