新城疫病毒HI抗体效价与流行株感染排毒之间的相关性

为了分析免疫鸡群中新城疫强毒感染流行的原因,明确抗体效价与流行株感染排毒率之间的关系,本研究以LaSota为抗原制备新城疫灭活疫苗,并以0.02mL和0.4mL的量分别免疫3周龄的SPF鸡10只。免疫后7、14、21d分别测定免疫鸡血清中的抗体HI效价。免疫后21d以基因Ⅶd亚型新城疫流行株JS5/05进行攻毒,攻毒后每天观察试验鸡的临床症状,并于攻毒后3、5、7d采集试验鸡的喉气管与泄殖腔棉拭样品进行病毒分离,结果显示,免疫3周后0.02mL和0.4mL疫苗免疫组鸡的血清HI抗体平均效价分别为5.4log2和8.2log2;0.02mL免疫组在攻毒后的排毒率达到100%,且排毒时间较长,而0.4mL免疫组在攻毒后的排毒率明显降低,且排毒时间较短。上述结果表明新城疫抗体效价与流行株感染排毒率之间存在明显的负相关。     

鸡新城疫免疫鸡群强毒感染与HI抗体水平关系的研究

应用RT-PCR方法对鸡新城疫4种不同免疫程序鸡群NDV强毒的感染进行监测。结果显示,鸡新城疫弱毒疫苗和油乳剂灭活疫苗同时接种的免疫鸡群NDV强毒的感染率最低。同时应用HA-HI试验对这4群鸡进行平行抽样检测其抗体效价,发现鸡群免疫水平整齐且平均HI效价在11 log2以上时,免疫鸡群基本不感染鸡NDV强毒。     

鸡新城疫不同免疫程序鸡群强毒感染的监测

本试验应用快速检测NDV强毒的RT-PCR方法对鸡新城疫4种不同免疫程序的鸡群NDV强毒的感染进行监测。每7d采一批样品，共采3批样品，用检测NDV强毒的RT-PRC进行检测。检测结果显示，鸡新城疫弱毒疫苗和油乳剂灭活疫苗同时接种的免疫鸡群感染NDV强毒的感染率最低。     

新城疫分离株免疫保护试验

对经过鉴定的新城疫病毒(NDV)分离株，按国家兽医生物制品质量标准制备油乳剂灭活疫苗，在隔离器中接种SPF鸡，设标准La Sota疫苗株作对照，进行免疫保护实验。免疫后，每7d采血监测NDV抗体。免疫后3周，利用ND强毒分离毒和F48E。分别进行交叉攻毒实验，同时设SPF鸡对照。每天观察，及时剖检发病鸡，检察鸡群病变，以确定疫苗的保护性，以便对常规生产中的免疫失败进行原因分析。     

五种市售鸡传染性鼻炎灭活疫苗免疫效力比较

本研究对国内市场上几个主要鸡传染性鼻炎灭活疫苗生产厂家生产的灭活疫苗免疫鸡只进行血清HI抗体水平测定和攻毒,比较不同公司所产疫苗效力的效力差异,并评估A、C型二价灭活疫苗两次免疫鸡群对国内B型分离株:DL-1株和最近从免疫失败鸡场分离到的SD-1株的交叉保护作用,分析免疫失败的原因.结果表明:A、D、E公司的疫苗免疫两次后,A型HI抗体阳性率分别为92.5%、100%和95%,滴度分别为33.9、55.1和59.9,攻毒保护率都是100%.C型HI抗体阳性率分别为72.5%、38.5%和77.5%,滴度分别为11.4、2.7和27,攻毒保护率分别为80%、70%和80%.而B和C公司的疫苗免疫两次后A型HI抗体阳性率分别为59.4%、77.1%,抗体滴度分别为5.4和21.8,攻毒保护率分别为50%和66.7%;C型HI抗体阳性率分别为54.1%和51.4%,抗体滴度分别为6.1和6.8,攻毒保护率分别为38.3%和50%.在五个疫苗产品中,以A、D、E的保护效力较好,B、C产品效力较差.另外,A、C型二价灭活疫苗免疫后不能对B型菌的攻击提供保护,其A、C型HI抗体阳性率、抗体滴度与对B型菌攻毒保护率无相关性.     

用RT-PCR方法监测湖南某肉鸡场鸡群新城疫强毒感染

应用RT PCR方法对弱毒疫苗免疫 7d后的鸡群进行NDV强毒的感染监测。每 7天采一批样品 ,共采 3批样品 ,从每一批样品中都检测到NDV强毒株的存在 ,证实免疫鸡群感染了NDV强毒     

VA5免疫增强剂对鸽新城疫病毒灭活疫苗的增效作用研究

试验旨在探究VA5免疫增强剂对鸽新城疫病毒（NDV）灭活疫苗（ND4416株）的免疫增效作用。选取160只健康鸽随机分为4组：ND4416株灭活疫苗组（NDV组）、ND4416株灭活疫苗与免疫增强剂（VA5）混合组（NDV+VA5组）、La Sota灭活疫苗组（La Sota组）及生理盐水空白对照组（C组）,进行免疫效力及免疫持续期试验。采用血凝抑制试验检测各组鸽免疫后不同时间点的血清抗体效价,结果显示,VA5免疫增强剂能够显著提高鸽NDV灭活疫苗血清抗体水平（P<0.05）。脾脏淋巴细胞转化试验结果显示,VA5能够有效刺激免疫鸽的淋巴细胞转化。在免疫后第30、90、180天,各组鸽子采用ND4416株进行攻毒试验,结果显示,NDV+VA5组在3个时间点的攻毒保护率均为100%,均高于La Sota组。免疫持续期试验结果显示,NDV+VA5组血清抗体水平在免疫后第21天达峰值11.20log₂,第180天仍能达到7.50log₂,攻毒保护率达100%,表明VA5免疫增强剂可延长鸽新城疫疫苗的免疫效力持续期至180 d。攻毒后体外排毒检测结果表明,VA5免疫增强剂能够缩短攻毒后鸽的体外排毒周期,减少体外排毒。综上,VA5免疫增强剂能够显著提高鸽NDV灭活疫苗的免疫效果,为研制效果更好的鸽NDV疫苗提供了基础依据,同时也为免疫增强剂的应用增加了试验数据。     

猪乙型脑炎(HW1株)细胞灭活疫苗免疫抗体水平分析

为评估猪乙型脑炎(HW1株)细胞灭活疫苗的免疫原性,用商品化的乙型脑炎鼠脑疫苗、乙型脑炎弱毒疫苗(SA14-14-2株)以及自制乙型脑炎细胞灭活疫苗(HW1株)分别免疫仔猪,通过抗体水平监测试验、中和抗体试验、小鼠攻毒保护试验分别检测了其特异性抗体消长情况、中和抗体效价产生情况及疫苗对小鼠的攻毒保护率。结果显示,3种疫苗均能产生中和抗体,乙型脑炎细胞灭活疫苗免疫组中和抗体水平要高于鼠脑疫苗和弱毒疫苗免疫组,乙型脑炎细胞灭活疫苗和弱毒疫苗免疫组对小鼠的攻毒保护率高于鼠脑疫苗免疫组,但两者之间差异不显著。抗体消长情况显示,至8周观测期结束,鼠脑疫苗免疫组的抗体阳性率为80%,乙型脑炎细胞灭活疫苗和弱毒疫苗免疫组抗体阳性率为100%。结果表明猪乙型脑炎(HW1株)细胞灭活疫苗的免疫原性优于鼠脑灭活疫苗和弱毒疫苗。     

1日龄中国黄羽肉鸡新城疫与传染性支气管炎二联弱毒活疫苗免疫保护试验

对1日龄黄羽肉鸡免疫新城疫与传染性支气管炎二联弱毒活疫苗——威支灵(即新威灵+H120),在21日龄进行新城疫强毒攻毒,与a疫苗(Mass株+La Sota克隆株)(保护率为86.7%)及c疫苗(LaSota+H120)(保护率为90%)免疫组相比,威支灵免疫组表现出了较高的保护力(保护率为96.7%),未免疫攻毒组的死亡率为40%。新城疫病毒HI检测结果表明强毒攻毒后的鸡群的新城疫HI抗体升高,同样证明了攻毒的有效性。     

新城疫分离株免疫保护试验

对经过鉴定的新城疫病毒穴NDV雪分离株,按国家兽医生物制品质量标准制备油乳剂灭活疫苗,在隔离器中接种SPF鸡,设标准LaSota疫苗株作对照,进行免疫保护实验。免疫后,每7d采血监测NDV抗体。免疫后3周,利用ND强毒分离毒和F48E9分别进行交叉攻毒实验,同时设SPF鸡对照。每天观察,及时剖检发病鸡,检察鸡群病变,以确定疫苗的保护性,以便对常规生产中的免疫失败进行原因分析。     

The resistance of meat chickens vaccinated by aerosol with a live V4 Newcastle disease virus vaccine in the field to challenge with a velogenic Newcastle disease virus

Meat chickens housed on a commercial broiler farm in Australia were vaccinated once at 10 to 11 days-of-age by aerosol with live V4 Newcastle disease virus (NDV) vaccine. Groups of vaccinated and unvaccinated birds were flown to Malaysia, where they were challenged with a virulent strain of NDV. Survival rates in vaccinated chickens challenged 7, 14, 21 or 31 d after vaccination were 0.47, 0.77, 0.97 and 0.92, respectively. All unvaccinated chickens died due to Newcastle disease (ND) following challenge. Chickens in Australia and Malaysia were bled and the serums tested for haemagglutination-inhibiting (HI) antibody to NDV. Many vaccinated birds with no detectable antibody, and all birds with a log2 titre of 2 or greater, survived challenge. The results showed that this V4 vaccine induced protective immunity in a significant proportion of chickens within 7 d of mass aerosol vaccination. This early immunity occurred in the absence of detectable circulating HI antibody. Non-HI antibody mediated immunity continued to provide protection up to 31 d after vaccination. Almost all vaccinated birds were protected within 3 w of vaccination. It is concluded that the V4 vaccine is efficacious and could be useful during an outbreak of virulent ND in Australia.     

Immunisation of fancy chickens against Newcastle disease]

The German Regulation on Fowl plague which is in force since 1994 laid down that any chicken of all races and all hybrids must be vaccinated against Newcastle disease (ND) in a mode that an adequate immunity is achieved. Onset, duration, and resistance to challenge of immunity induced by vaccination is well documented in the scientific literature for hybrid chicken of the layer and meat types. These data prove also innocuity and efficacy of the registered vaccines. In contrast, only a few and incomplete data exist on the development of ND directed immunity in fancy chickens. The present study describes vaccinations of chickens of 14 different hobby breeds with live LaSota vaccine (conjunctival application of 10(6) embryo-infective dose50 per bird) and with an inactivated oil-emulsion vaccine (intramuscular application of 0.5 ml per bird) and subsequent intramuscular challenge infections using the highly virulent NDV strain Herts 33/66. Chickens of all 14 breeds tolerated the application of both vaccines. All fancy chickens reacted with the production of serum antibodies which were measured in the haemagglutination inhibition (HI) and virus neutralisation (VN) tests. According to the scientific literature, maximal antibody levels are reached in hybrid chickens between day 10 and 20 post vaccination. In contrast, in fancy chickens the antibody maxima are delayed to the seventh to eighth week post vaccination. All fancy chickens vaccinated either once with live LaSota virus or with live and inactivated vaccines resisted challenge with the highly virulent Herts 33/66 strain of NDV and did not develop any signs of disease. There are indications for gradual differences in susceptibility of different breeds of fancy chickens. The levels of non-specific neutralisation as measured in the virus neutralisation test differ between breed. Also, the viral content in tissues obtained from non-vaccinated but challenged birds differ markedly. It is concluded from the results of this study that fancy chickens can also successfully protected against Newcastle disease by using live and inactivated vaccines which are licensed for hybrid chickens. However, the optimal time for the detection of maximal antibody levels in fancy chickens is reached seven to eight weeks post vaccination.     

鸽禽Ⅰ型副粘病毒油佐剂灭活苗对雏鸡免疫效果评价

用鸽Ａ／ＰＭＶ－１油佐剂灭活苗与ＮＤＶ油佐剂灭活苗分别免疫雏鸡,免疫后２１ｄ抗体水平达到峰值,免疫后４２ｄ用新城疫强毒对两种疫苗免疫鸡分别进行攻击,鸽Ａ／ＰＭＶ－１油佐剂灭活苗免疫组保护率为７３．３３％,ＮＤＶ油佐剂灭活苗免疫组保护率为９９．６７％。     

Antibody responses to inactivated vaccines and natural infection in cattle using bovine viral diarrhoea virus ELISA kits: Assessment of potential to differentiate infected and vaccinated animals

Bovine viral diarrhoea virus (BVDV) is one of the most common and economically important viral infections of cattle. As vaccination is common in most European countries, differentiation between infected and vaccinated animals is one of the key challenges facing BVDV eradication campaigns. This study was designed to compare the ability of commercial ELISA kits to differentiate antibodies generated following vaccination with four different commercial inactivated BVDV vaccines from antibodies generated following challenge with virulent BVDV. Although none of the tested vaccine–ELISA combinations was able to differentiate an infected from a vaccinated animal (DIVA) at the individual animal level, p80 blocking ELISAs, in combination with inactivated BVDV vaccines, may have some value under certain circumstances at herd level. In most cases, antibody responses to BVDV vaccines cannot be clearly distinguished from responses seen in the early phase of natural infection. No commercial BVD vaccine showed true marker qualities for DIVA using p80 blocking ELISAs.     

鸡新城疫、减蛋综合征、传染性支气管炎三联油佐剂灭活苗的研究Ⅰ、三联灭活苗对鸡免疫试验

用新城疫病毒克隆７９株，减蛋综合征病毒ＮＥ＿４株和传染性支气管炎病毒Ｍ＿（４１）株分别接种于鸡胚和鸭胚，并收取其鸡、鸭胚尿囊液毒，经甲醛灭活，按一定比例配比，以矿物油为佐剂制成三联油佐剂灭活苗。本苗接种于产蛋后备鸡，免疫后７天产生免疫应答，免疫后３０天保护率达９０％～１００％，免疫后六个月攻毒，ＮＤ和ＩＢ保护宰为１００％，ＥＤＳ＿（７６）为９５％。１９９２～１９９４上半年，本苗在江苏、安徽、山东等省的一些鸡场免疫十万余只鸡，均获得满意效果。     

Protective antibody response produced by the chickens vaccinated with green coloured thermostable Newcastle disease virus

The efficacy of green-coloured (GC) I-2 Newcastle disease vaccine was determined in the present study. I-2 vaccine was mixed with a green coloured dye and stored at 4°C for 6 months while assayed for the virus infectivity at a monthly interval. Chickens were vaccinated with the GC vaccine by eye drop. Serum samples were collected from all birds before and after vaccination at weekly interval for 4 weeks and tested for haemagglutination-inhibition (HI) antibody against Newcastle disease virus (NDV). These chickens were challenged with NDV virulent strain four weeks after vaccination. The results showed that there was no difference between the infectivity titres of GC and uncoloured vaccines. However, chickens vaccinated with GC vaccine produced higher HI antibody titres than chickens vaccinated with uncoloured vaccine. Results from the challenge trial showed that all vaccinated chickens survived whereas all unvaccinated chickens died. The findings from this study have shown that the GC vaccine is safe and produced protective antibodies against NDV in vaccinated chickens. Wambura, P. N., 2008. Protective antibody response produced by the chickens vaccinated with green coloured thermostable Newcastle disease virus. Tropical Animal Health and Production.     

含粘膜佐剂的鸡新城疫疫苗诱导雏鸡非特异性免疫应答的研究

为研究分析重组大肠杆菌不耐热肠毒素（labile enterotoxin,LT）作为粘膜佐剂,配伍鸡新城疫疫苗的冻干样品对免疫鸡非特异性免疫应答的影响,在前期已经构建的LTR72/G192基础上,选择2、4μg LTRG蛋白作为每羽份疫苗添加量,及降低新城疫病毒（Newcastle disease virus,NDV）50%抗原量等配伍条件。按照生产条件制备冻干疫苗,进行雏鸡免疫试验,免疫后24、48、72 h采集脾脏、胸腺淋巴结,检测几种非特异性细胞因子表达水平。结果表明：IL-6、INF-γ水平在各疫苗免疫后24h即升高,48 h达最高值;添加2、4μg LTRG蛋白的NDV疫苗组IFN-β、TNF-α水平在48 h左右显著升高,其中含4μg LTRG疫苗组与其他组差异具有极显著统计学意义（P〈0.01）;IL-6、IFN-γ转录水平有所增强,但各组间差异不具有显著统计学意义（P〉0.05）,72 h左右几种细胞因子水平均迅速下降,与NDV疫苗接种组相近。由此可见,LTRG能辅助抗原诱导免疫雏鸡的非特异性免疫应答,有利于对感染病毒的清除。     

Effect of breeder vaccination on immunization of progeny against Newcastle disease

Two experiments were conducted to determine the effect of breeder vaccination program and maternal antibody on the efficacy of Newcastle disease immunization of 1-day-old chicks. Experimental protocol was the same for both. In the first experiment, broilers were from breeders that were 32 weeks old, and in the second experiment, broilers were from breeders 50 weeks old. Breeders received three live Newcastle disease virus (NDV) vaccines and either a killed vaccine at 18 weeks or continual live boosting at 60-to-70-day intervals through lay. Broilers were vaccinated at 1 day of age with a commercial coarse-spray machine; they were bled, sera were examined for antibody against NDV, and broilers were challenged with virulent NDV at 2, 4, and 6 weeks of age. In the first experiment, maternal antibody was higher in chicks from the younger breeders given the inactivated vaccine, and in the second experiment maternal antibody was higher in chicks from older breeders given continual live vaccines. Higher antibody in 1-day-old broilers resulted in fewer vaccine-induced reactions, less vaccine virus shed, and decreased duration of vaccine-induced immunity from coarse-spray vaccination.     

Protective efficacy of commercial inactivated Newcastle disease virus vaccines in chickens against a recent Korean epizootic strain

Despite the intensive vaccination policy that has been put in place to control Newcastle disease virus (NDV), the recent emergence of NDV genotype VII strains in Korea has led to significant economic losses in the poultry industry. We assessed the ability of inactivated, oil-emulsion vaccines derived from La Sota or Ulster 2C NDV strains to protect chickens from challenge with Kr-005/00, which is a recently isolated Korean epizootic genotype VII strain. Six-week-old SPF chickens were vaccinated once and challenged three weeks later via the eye drop/intranasal route. All vaccinated birds were fully protected from disease, regardless of the vaccine strains used. All vaccinated and challenged groups showed significant sero-conversion 14 days after challenge. However, some vaccinated birds, despite being protected from disease, shed the challenge virus from their oro-pharynx and cloaca, albeit at significantly lower titers than the unvaccinated challenged control birds. The virological, serological, and epidemiological significance of our observations with regard to NDV disease eradication is discussed.     

重组禽流感灭活苗和禽流感灭活苗对鸡免疫效果的观察

用重组禽流感灭活苗接种10日龄、14日龄和21日龄的SPF鸡,接种后HI抗体效价无显著差异。将H5N1和H5N2疫苗分别接种21日龄SPF鸡,结果表明,H5N1和H5N2均能刺激SPF鸡产生较高的HI抗体;分别接种三黄鸡,接种后21 d,H5N1能刺激三黄鸡产生较高的HI抗体;而H5N2不能刺激三黄鸡产生合格的HI抗体,与SPF鸡免疫组相比差异显著。经过二次接种,HI抗体平均为8.9 log2,与SPF鸡组接种后42 d的各组相比差异不显著,而与一免后21 d的各组HI抗体效价相比差异显著。表明应用禽流感灭活苗对三黄鸡免疫接种,必须进行二免方可达到理想免疫效果,而应用重组禽流感灭活苗对三黄鸡进行免疫接种,一次免疫即可获得较高的HI抗体效价。