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1.
以禽流感病毒(AIV)H5N4株,新城疫病毒(NDV)LaSota株与传染性支气管炎病毒(IBV)M41株为抗原研制了AI-ND-IB三联油乳剂灭活疫苗,并对疫苗的物理性状,安全性,免疫效力,保存期及抗体消长规律进行了检测,结果表明,疫苗在免疫后3周后6个月内,对AIV-H5N4,NDV-北京株的攻击均获全部保护,在免疫后52周内,免疫鸡箅清中AIV-N5N4,MDV,IBV的HI抗体也保持较高的水平,疫苗在4℃保存15个月,其免疫力没有下降。  相似文献   

2.
为评价H9N2亚型重组禽流感病毒(AIV)灭活疫苗Re-9株的免疫效力,本研究选取2010年~2011年分离的5株H9N2亚型AIV进行攻毒保护实验。这5个分离株均为类A/CK/Beijing/1/94病毒株,其HA和NA基因与Re-9株及其亲本株的同源性介于90.6%~97.5%和88.1%~98.7%之间,其抗原相关值在66.67%~100%之间。将Re-9株为种毒制备灭活疫苗,免疫4周龄SPF雏鸡后,3周时平均HI抗体效价达9.5 log2;在免疫后3周以2×107EID50的剂量攻击亲本株和5株流行病毒株,攻毒后采集3 d、5 d、7 d的拭子,免疫组拭子样品病毒检测均为阴性;对照组3 d、5 d拭子病毒检测的阳性率均在80%以上,7 d的阳性率在60%以下。以上结果表明灭活疫苗Re-9株抗原针对性强,而且具有良好的免疫效力,能够抵御近年来分离的H9N2亚型AIV,是理想的H9N2亚型禽流感疫苗株。  相似文献   

3.
为评估当前应用的Re-8株种毒相关禽流感灭活疫苗对野鸟源H5N8流感病毒的免疫预防效果,本研究将重组禽流感病毒(AIV)H5亚型Re-8株灭活疫苗(H5N1亚型,Re-8株)和重组AIV(H5+H7)灭活疫苗(H5N1Re-8株+H7N9 H7 Re-1株)分别以0.3 m L/只的剂量接种3周龄SPF鸡,免疫3周时进行HI抗体检测和攻毒试验。结果显示,上述2种疫苗免疫的SPF鸡血清中针对H5亚型Re-8株抗原的HI抗体均在8 log2以上,以105EID50的剂量、鼻腔感染途径攻击野鸟源H5N8病毒BHG/QH/2/16和BHG/Tibet/3/16后,所有免疫组鸡在14 d观察期内均全部健活,不排毒,而对照组鸡在攻毒后4 d内全部发病、死亡、排毒。现地免疫重组AIV H5亚型三价灭活疫苗(Re-6株+Re-7株+Re-8株)的商品蛋鸡直接进行HI抗体检测和攻毒试验,结果显示,免疫蛋鸡血清中针对Re-8株抗原的HI抗体平均滴度为8.3 log2,以相同攻毒方式和剂量分别攻击2株H5N8病毒后,免疫鸡也获得完全免疫保护,不发病、不死亡、不排毒。本研究结果表明,含有重组AIV H5 Re-8株抗原的灭活疫苗可有效防控野鸟源H5N8流感病毒,为我国及其他国家H5N8亚型禽流感免疫防控提供了科学依据。  相似文献   

4.
为研究双顺反子DNA疫苗对禽流感病毒(AIV)的保护作用,将H5和H7亚型AIV的HA基因克隆到同一表达栽体上,构建了双顺反子HA基因表达质粒pCI—H5HA—H7HA。以此质粒肌注免疫4周龄SPF鸡,首次免疫后3周加强免疫,同时设pCI—H5HA和pCI—H7HA联合免疫组及空白对照组,每周采血用微量血凝抑制法检测HI抗体。加强免疫后3周分别以100LD50的高致病力禽流感病毒(HPAIV)A/Goose/Guangdong/1/96(H5N1)和A/FPv/Rostock/34〈(H7N1)进行致死性攻击。结果显示各免疫组均可刺激鸡体产生H5、H7特异性抗体,pCI—H5HA—H7HA诱导产生的抗体对H5N1和H7N1的攻毒保护分别为50%和10%,而pCI—H5HA和pCI—H7HA联合免疫的攻毒保护均为70%。表明双顺反子质粒可诱导鸡产生较好或一定的保护,但免疫效果不够理想,推测与DNA的摄取及其体内表达有关,可望通过调整DNA疫苗的多种因素提高免疫效果。  相似文献   

5.
为评价重组禽流感病毒灭活疫苗鸡胚源H5N1亚型Re-6株、鸡胚源H5N1亚型Re-6+Re-8株灭活疫苗、细胞源Re-6+Re-8株灭活疫苗及水禽专用H5N2亚型D7株灭活疫苗4个产品对番鸭的免疫效果,分别取四种疫苗分别免疫20日龄番鸭,125只/组,免后35日采血测定HI抗体效价。结果表明,4种疫苗免疫后用Re-6抗原检测抗体依次分别为8.1log2、9.3log2、8.9log2、7.0log2,用Re-8抗原检测抗体分别为1.5log2、9.9log2、8.7log2、7.5log2,用D7抗原检测抗体分别为0.3log2、7.6log2、5.6log2、6.5log2。四种疫苗免疫效果由高至低依次为:鸡胚源H5N1亚型Re-6+Re-8株灭活疫苗细胞源Re-6+Re-8株灭活疫苗H5N2亚型D7株灭活疫苗鸡胚源H5N1亚型Re-6株灭活疫苗。  相似文献   

6.
为充分了解10多年来在生产中普遍使用的H9N2亚型禽流感(AI)灭活疫苗(F株)对鸡群的免疫保护效果,本研究以F株灭活疫苗分别接种SPF鸡和罗曼鸡,通过检测其抗体水平,分析比较抗体消长规律;同时以2009~2010年间从免疫鸡群中分离到的9株H9N2亚型AIV为素材,通过F株灭活苗免疫攻击试验,来评价该疫苗对上述9株分离株体内感染的免疫保护效果。结果显示:F株灭活疫苗免疫SPF鸡和罗曼鸡3周后,产生的HI抗体效价均在7log2以上,且持续时间长,SPF鸡达15周,罗曼鸡在11周以上。SPF鸡免疫群用F9株、L9株、S9株和D9株和F株攻击7d后,对鸡的咽喉和泄殖腔排毒有100%的抑制作用,用其它5株(F119、W9、YD、M和D119)攻击后的抑制作用为90%;罗曼鸡免疫群用L9株、F9株、S9株、D9株、W9株和F株攻击7d后,对鸡咽喉和泄殖腔排毒有100%的抑制作用,用其它4株(F119株、YD株、M株和D119株)攻击后的抑制作用为90%;未接种疫苗的对照组鸡攻击7d后排毒率均为10/10。  相似文献   

7.
在研究1998-2008年中国H9N2亚型禽流感病毒(AIV)分离株HA基因的进化时,发现在25个毒株中有2个致病性最强的毒株因HA基因第145位氨基酸的突变导致产生1个潜在的糖基化位点,从而使其不与单抗H6、F6等反应。为进一步探究这类变异毒株HA基因变异对H9亚型AIV的抗原性和免疫原性的影响,本试验对12株HA蛋白S145N变异的H9N2AIV进行了交叉中和试验和交叉攻毒试验。结果显示,不同H9N2S145N变异株与疫苗株间在抗原性上变化不大,或无显著差异(0.5≤R≤0.67)。但参照现有的H9灭活疫苗效力检验方法对HP疫苗免疫鸡进行攻毒,用HP株攻毒对照组0/5保护,免疫组保护≥9/10,达到了H9灭活疫苗质量标准要求;但用S145N变异株N3攻毒,仅保护2/10~6/10,且随免疫量剂量的增加,抗体水平的提高,攻毒保护也依次升高。对H9变异株疫苗(N1、N2、N3、N8)免疫鸡用N3攻毒,仅保护2/5~4/5,N3同源抗体也不能有效地阻止其攻毒后的排毒。用N3、N6 2个变异株交叉攻毒,采用与疫苗株攻毒相同的剂量作攻毒试验也得到类似结果。表明高于6log2的抗体能抵抗疫苗株和大多数流行毒株攻毒后的排毒,但不能抵抗S145N变异株攻毒后的排毒。这类毒株免疫原性上的变化与病毒HA基因的变异密切相关。因HA基因145~147aa位增加了1个NGT,导致三维空间构象的变化,并影响其邻近的受体结合位点,从而使这类毒株致病性提高,免原性发生改变。虽然这一类变异株或免疫逃逸毒株仅占当前流行毒株总数的5%~7%,但在强大的免疫压力和自然选择下有可能逐步成为优势毒株,造成更大的危害,这为该病的防控提出了新的挑战。  相似文献   

8.
禽流感H9亚型灭活油乳剂疫苗不同剂量的免疫效果比较   总被引:3,自引:0,他引:3  
将47只28日龄SPF鸡分为4组,第1~3组为试验组,每组12只,分别肌肉注射禽流感H9亚型灭活油乳剂疫苗0.1、0.3、0.5mL/只,第4组11只为对照组。各组鸡在免疫后1、2、3周采血,测定H9抗体水平;在免疫后3周用1:10稀释的AIV H9N2攻毒,0.2mL/只。攻毒后第2、3、4周继续测定H9抗体水平,观察了疫苗对鸡的保护效果。结果显示,0.5mL/只剂量的免疫效果比0.1mL/只和0.3mL/只剂量的免疫效果好;攻毒用的AIV H9N2的致病力低,对所有试验鸡均不致死。  相似文献   

9.
在野生禽类中流行的禽流感病毒(AIV)对公众健康构成严重威胁,迫切需要针对多种禽流感亚型的人用和兽用疫苗。本试验制备了针对H5、H7和H9 3种AIV亚型抗原的病毒样颗粒(VLPs)(分别源自H5N1、H7N3和H9N2病毒)。VLPs还含有流感N1神经氨酸酶和逆转录病毒gag蛋白。利用杆状病毒表达系统制备H5/H7/H9/N1/gag VLP。本试验测定了其包括血凝素和神经氨酸酶活性在内的生化特性、功能和抗原特性。在鸡禽流感攻击模型中进一步评估VLPs的安全性、免疫原性和针对异源AIV(包括H5N2、H7N3和H9N2亚型AIV)的保护功效。结果显示,接种疫苗的禽类在H5N2和H7N3高致病性AIV的攻击中未出现死亡,而对照组全部死亡。用低致病性H9N2亚型AIV攻毒后也可检测到免疫应答,结果表明H5/H7/H9/N1/gag VLP为具有广泛免疫保护作用的禽流感疫苗的开发提供了新方法。  相似文献   

10.
为有效防控2006年以来出现的H5亚型7.2分支禽流感病毒(AIV)引起的免疫鸡群高致病性禽流感(HPAI)的流行,我们构建了重组AIV Re-4疫苗株,研制出含有重组AIV Re-4株的H5亚型二价系列灭活疫苗,并在我国北方地区使用,有效地控制了其流行。2012年我国北方地区再次出现7.2分支病毒引起的HPAI疫情。为评估现有H5亚型二价系列灭活疫苗对该分支病毒的免疫保护效力,本研究首先通过SPF鸡进行免疫攻毒试验评估。结果表明,分别以每羽份(0.3 mL/只)的Re-5+Re-4株和Re-6+Re-4株重组AIV H5二价油乳剂灭活疫苗免疫SPF鸡,免疫3周后针对重组AIV Re-4株的HI抗体均达到8 log2以上;经鼻腔接种7.2分支AIV CK/NX/2/12株(100 LD50)攻毒后,免疫鸡均获得完全保护,即无任何临床症状和排毒现象,而对照组SPF鸡全部发病死亡。此外,以哈尔滨当地养殖场中免疫H5亚型AIV灭活疫苗的48只商品蛋鸡进行攻毒试验,结果显示,商品蛋鸡血清中针对重组AIV Re-4株HI抗体平均滴度为8.3 log2,采用相同方式攻毒后也获得完全保护。本研究结果表明,Re-5+Re-4株和Re-6+Re-4株重组AIV H5二价灭活疫苗均能够对H5亚型7.2分支病毒的攻击提供良好的免疫保护效果。  相似文献   

11.
In this study, two highly pathogenic avian influenza (HPAI) H5N8 viruses were isolated from chicken and geese in 2018 and 2019 (Chicken/ME-2018 and Geese/Egypt/MG4/2019). The hemagglutinin and neuraminidase gene analyses revealed their close relatedness to the clade-2.3.4.4b H5N8 viruses isolated from Egypt and Eurasian countries. A monovalent inactivated oil-emulsion vaccine containing a reassortant virus with HA gene of the Chicken/ME-2018/H5N8 strain and a bivalent vaccine containing same reassortant virus plus a previously generated reassortant H5N1 strain (CK/Eg/RG-173CAL/17). The safety of both vaccines was evaluated in specific-pathogen-free (SPF) chickens. To evaluate the efficacy of the prepared vaccines, 2-week-old SPF chickens were vaccinated with 0.5 mL of a vaccine formula containing 108/EID50 /dose from each strain via the subcutaneous route. Vaccinated birds were challenged with either wild-type HPAI-H5N8 or H5N1 viruses separately at 3 weeks post-vaccine. Results revealed that both vaccines induced protective hemagglutination-inhibiting (HI) antibody titers as early as 2 weeks PV (≥5.0 log2). Vaccinated birds were protected clinically against both subtypes (100 % protection). HPAI-H5N1 virus shedding was significantly reduced in birds that were vaccinated with the bivalent vaccine; meanwhile, HPAI-H5N8 virus shedding was completely neutralized in both tracheal and cloacal swabs after 3 days post-infection in birds that had been vaccinated with either vaccine. In conclusion, the developed bivalent vaccine proved to be efficient in protecting chickens clinically and reduced virus shedding via the respiratory and digestive tracts. The applicability of the multivalent avian influenza vaccines further supported their value to facilitate vaccination programs in endemic countries.  相似文献   

12.
The serological response and protective immunity elicited in the chicken by the pathogenic Ap3AS strain and the moderately pathogenic 80083 strain of Mycoplasma gallisepticum and variants of strain 80083 attenuated by repeated passage in mycoplasma broth were investigated. Strain 80083 elicited a substantial serum antibody response after administration either in drinking water or by conjunctival sac instillation to 7-week-old SPF chickens. No vaccinated chickens developed air sac lesions when challenged by intra-abdominal (IA) injection with the virulent Ap3AS strain. Chickens vaccinated with strain 80083M (50 broth passages) showed only a weak serological response but were substantially protected when challenged 4 weeks after vaccination. Chickens vaccinated with 80083H (100 broth passages) were serologically negative 4 weeks after vaccination and developed severe air sac lesions after challenge. Thirty-seven-week-old hens vaccinated 6 months previously with strain 80083 had high serum antibody levels and were completely protected against IA challenge with the homologous strain. However, 4/6 showed mild air sac lesions when challenged intra-abdominally with strain Ap3AS. Another group showed high M. gallisepticum serum antibody levels 6 months after vaccination with strain Ap3AS but 4/6 and 2/6 showed mild lesions after IA challenge with strains Ap3AS or 80083, respectively. Strains 80083 or 80083M were administered by conjunctival sac instillation to susceptible 11-week-old commercial pullets at the time of fowl pox vaccination. The concurrent use of both vaccines had no apparent adverse effect on the health of the chickens. Similar protection against IA challenge with strain Ap3AS was produced with the M. gallisepticum vaccines whether used alone or in combination with fowl pox.  相似文献   

13.
In contrast to chickens, there is a paucity of information on the potency of H5 vaccines to protect turkeys against the highly pathogenic avian influenza (HPAI) H5N1 virus infections. In this study, 4 groups, 10 turkey poults each, were vaccinated at seven days old with one of H5N2 or H5N1 commercial vaccines or one of two prepared H5N1 vaccines from a local Egyptian variant HPAI H5N1 (EGYvar/H5N1) strain. At 35 days age, all vaccinated and 10 non vaccinated birds were challenged intranasal with 10(6) EID(50)/0.1 ml of EGYvar/H5N1. All vaccines used in this study were immunogenic in turkeys. There was no cross reaction between the commercial vaccines and the Egyptian variant H5N1 antigen as obtained by the hemagglutination inhibition test. Birds vaccinated with H5N2 vaccine were died, while other H5N1 vaccinated groups have had 20-40% mortality. The highest virus excretion was found in non-vaccinated infected and H5N2 vaccinated birds. Eleven peculiar amino acid substitutions in H5 protein of the variant strain were existed neither in the vaccine strains nor in the earliest H5N1 virus introduced into Egypt in 2006. In conclusion, single vaccination at seven days old is inadequate for protection of meat turkeys against variant HPAI H5N1 challenge and multi-dose vaccination at older age is recommended. For the foreseeable future, continuous evaluation of the current vaccines in H5N1 endemic countries in the face of virus evolution is a paramount challenge to mitigate the socio-economic impact of the virus.  相似文献   

14.
In Egypt, continuous circulation of highly pathogenic avian influenza (HPAI) H5N1 viruses of clade 2.2.1 in vaccinated commercial poultry challenges strenuous control efforts. Here, vaccine-derived maternal AIV H5 specific immunity in one-day old chicks was investigated as a factor of vaccine failure in long-term blanket vaccination campaigns in broiler chickens. H5 seropositive one-day old chicks were derived from breeders repeatedly immunized with a commercial inactivated vaccine based on the Potsdam/H5N2 strain. When challenged using the antigenically related HPAIV strain Italy/98 (H5N2) clinical protection was achieved until at least 10 days post-hatch although virus replication was not fully suppressed. No protection at all was observed against the Egyptian HPAIV strain EGYvar/H5N1 representing a vaccine escape lineage. Other groups of chicks with maternal immunity were vaccinated once at 3 or 14 days of age using either the Potsdam/H5N2 vaccine or a vaccine based on EGYvar/H5N1. At day 35 of age these chicks were challenged with the Egyptian HPAIV strain EGYcls/H5N1 which co-circulates with EGYvar/H5N1 but does not represent an antigenic drift variant. The Potsdam/H5N2 vaccinated groups were not protected against EGYcls/H5N1 infection while, in contrast, the EGYvar/H5N1 vaccinated chicks withstand challenge with EGYvar/H5N1 infection. In addition, the results showed that maternal antibodies could interfere with the immune response when a homologous vaccine strain was used.  相似文献   

15.
Avian influenza vaccines are commonly used in the poultry industry, and some medicinal plants can increase the efficacy of such vaccines. The objective of this study was to evaluate the effect of Immulant® (IMU) (a commercial product based on Echinacea and Nigella sativa) on stress induced by dexamethasone (DEX) in chickens vaccinated (VAC) against the H9N2 avian influenza virus (AIV-H9N2). Seven experimental groups were included: the negative control, VAC, DEX, VAC + DEX, VAC + DEX + IMU, VAC + IMU and IMU groups. The vaccinated chickens (at 10 days of age) were injected daily with DEX for three days pre-vaccination and for three days pre-challenge and orally administered 1% IMU for 6 weeks post-vaccination (PV). The chickens were then challenged intranasally with AIV-H9N2 at 28 days PV. Serum, blood, tracheal and cloacal swabs and tissue samples were collected in the 1st and 4th weeks PV and at different time points post-challenge. The results showed significant changes (P ≤ 0.05) in oxidative stress and antioxidant biomarkers (malondialdehyde, nitric oxide and reduced glutathione), haematological and immunological parameters, final live weights, relative organ weights and histopathological lesions between the VAC+DEX group and the VAC group. Moreover, IMU significantly increased protection rates post-challenge, HI antibody titers and heterophil phagocytic activity and decreased DEX-induced stress and virus shedding titers. In conclusion, oral administration of 1% IMU for six weeks can enhance the immune response after AI-H9N2 vaccination and reduce the pathogenicity of infection in stressed chickens.  相似文献   

16.
OBJECTIVE: To evaluate the vaccine efficacy of a fowlpox virus recombinant expressing the H7 haemagglutinin of avian influenza virus in poultry. PROCEDURE: Specific-pathogen-free poultry were vaccinated with fowlpox recombinants expressing H7 or H1 haemagglutinins of influenza virus. Chickens were vaccinated at 2 or 7 days of age and challenged with virulent Australian avian influenza virus at 10 and 21 days later, respectively. Morbidity and mortality, body weight change and the development of immune responses to influenza haemagglutinin and nucleoprotein were recorded. RESULTS: Vaccination of poultry with fowlpox H7 avian influenza virus recombinants induced protective immune responses. All chickens vaccinated at 7 days of age and challenged 21 days later were protected from death. Few clinical signs of infection developed. In contrast, unvaccinated or chickens vaccinated with a non-recombinant fowlpox or a fowlpox expressing the H1 haemagglutinin of human influenza were highly susceptible to avian influenza. All those chickens died within 72 h of challenge. In younger chickens, vaccinated at 2 days of age and challenged 10 days later the protection was lower with 80% of chickens protected from death. Chickens surviving vaccination and challenge had high antibody responses to haemagglutinin and primary antibody responses to nucleoprotein suggesting that although vaccination protected substantially against disease it failed to completely prevent replication of the challenge avian influenza virus. CONCLUSION: Vaccination of chickens with fowlpox virus expressing the avian influenza H7 haemagglutinin provided good protection against experimental challenge with virulent avian influenza of H7 type. Although eradication will remain the method of first choice for control of avian influenza, in the circumstances of a continuing and widespread outbreak the availability of vaccines based upon fowlpox recombinants provides an additional method for disease control.  相似文献   

17.
将禽流感病毒血凝素 H9A基因克隆入插入载体 p FG11S中 ,通过酶切鉴定获得了正向转移载体 p FG11SHA;将其与禽痘病毒疫苗株 (w FPV)共转染鸡成纤维细胞 (CEF) ,通过蓝白斑筛选纯化得到重组病毒 r FPV- Ps- HA;以间接免疫荧光法证实 HA基因得到了表达。将该病毒经颈部皮下免疫 1日龄 SPF鸡 ,免疫后 15 d以 H9亚型禽流感病毒 F株翅静脉攻毒 ,攻毒后第 5天采集泄殖腔棉拭子样品进行病毒分离。将此重组病毒与以痘苗病毒 P7.5启动子表达相同基因的重组病毒 r FPV- P7.5 - HA作比较 ,结果表明 ,r FPV- Ps- HA相对于 r FPV- P7.5 - HA明显抑制了病毒的排出 ;攻毒后第 2、5、7、9、11天分别对 r FPV- Ps- HA、油乳剂灭活苗免疫鸡进行泄殖腔、气管排毒规律的检测 ,发现疫苗组均能很好地抑制排毒 ,攻毒对照组泄殖腔的排毒率明显高于气管排毒率  相似文献   

18.
Tetanus toxoid (TT) was assessed as a positive marker for avian influenza (AI) virus vaccination in chickens, in a vaccination and challenge study. Chickens were vaccinated twice with inactivated AI H5N2 virus vaccine, and then challenged three weeks later with highly pathogenic AI H5N1 virus. Vaccinated chickens were compared with other groups that were either sham-vaccinated or vaccinated with virus with the TT marker. All sham-vaccinated chickens died by 36 hours postinfection, whereas all vaccinated chickens, with or without the TT marker, were protected from morbidity and mortality following exposure to the challenge virus. Serological testing for H5-specific antibodies identified anamnestic responses to H5 in some of the vaccinated birds, indicating active virus infection.  相似文献   

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