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1.
应用YCA18株第8代细胞培养物（YCA18－8）经口鼻和静脉接种犬腺(CAV)SN本＜1：2的易感犬作安全试验，结果未见任何CAV临床症状与病理解剖学改变；用不同剂量的YCA18－8分组免疫CAV易感犬，经SN抗体测定与用CAV强毒攻击试验，结果SN抗体达1：16以上的犬95％以上可获得免疫保护，最低免疫量为10^4TCID50；应用YCA18－8分别免疫母源抗体达1：4和1：8的两组试验犬，第一次免疫14d后SN抗体均未有升高，追加2－3次免疫后SN抗体才逐渐上升至1：16以上的免疫保护水平；用CAV易感犬和MDCK分别将YCA18连续传8代和20代，结果对犬仍然安全，对犬的免疫原性未见下降，最低免疫量仍为10^4TCID50；与CDV和CPV弱毒作免疫互扰试验，结果与各弱毒的单独免疫结果未见差异；将YCA18－8冰冻保存于一30℃，6个月内TCID50仍不低于10^-4/0.1ml，经加明胶－蔗糖低温真空冻干后，4℃和－30℃保存1年，TCID50均仍维持在10^-4/0.1ml以上，经YCA18－20 3次免疫的试验犬，1年后SN抗体仍在最低抗体保护值1：16以上。 相似文献
2.
应用纯化后的犬冠状病毒 (CCV)YS1株细胞培养致弱的弱毒 (CCVYS1V60 ) ,经口鼻和肌肉接种CCV ,SN抗体小于 1∶2的易感犬作安全试验 ,结果未见任何CCV临床症状与病理解剖学改变 ;用不同剂量的该CCV弱毒分组免疫CCV易感犬 ,经SN抗体测定与用CCV强毒攻毒试验 ,结果SN抗体达 1∶60以上的犬 90 %以上可获得免疫保护 ;应用该CCV弱毒分别免疫母源抗体达 1∶4和 1∶8的 2组试验犬 ,第 1次免疫 1 4d后SN抗体均未见升高 ,追加 2～ 3次免疫后 ,SN抗体才逐渐上升至 1∶60以上的免疫保护水平 ;用CCV易感犬和猫肾传代细胞 (CRFK)分别将该CCV细胞培养弱毒连续传 5代和 2 0代 ,结果对犬仍然安全 ,免疫原性也未见下降 ;与犬瘟热病毒 (CDV)、犬传染性肝炎病毒 (ICHV)和犬细小病毒(CPV)弱毒作免疫互扰试验 ,结果与各弱毒的单独免疫结果未见差异 ;该毒的免疫期在 1年以上 ,- 2 0℃冻结保存的保存期为 9个月。 相似文献
3.
禽巴氏杆菌 B_(26)-T_(1200)弱毒疫苗株是由一株代号为B_(26)的本地鸭源强毒株经含0.1%血红素马丁汤培养基连续传1200代获得的。该弱毒株经血斜连传30代或易感鸡体连传5代无返强现象;以3000万活菌免疫鸡可抵抗强毒攻击。该弱毒株具有良好的安全性和免疫原性. 相似文献
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5.
为研究犬腺病毒(CAV)致弱疫苗的免疫原性,本研究将病犬的组织样品接种于MDCK细胞内,进行病毒分离及鉴定。鉴定结果显示,分离的病毒在MDCK细胞内产生明显的细胞病变(CPE),电镜下可见典型的腺病毒粒子;回归动物试验显示,该分离株可导致犬出现明显的CAV感染症状;PCR鉴定结果表明分离的病毒为CAV,命名为CAV-H株;将CAV-H株接种MDCK细胞连续传代至110代,在传代过程中,病毒滴度由初始105.0 TCID50/0.1 mL上升至107.0 TCID50/0.1 mL,而CAV对犬的致病力逐渐降低;免疫效力试验结果表明,CAV-H可对同源强毒攻击的犬提供完全的免疫保护作用,可作为理想的疫苗候选毒株。 相似文献
6.
选用从犬科动物貉中分得的貉细小病毒CR86106株为种毒,用猫肾传代细胞F81系培养增殖,制成犬细小病毒性肠炎弱毒疫苗(M-CPV)。该苗对猪红细胞的HA效价平均156,对F81细胞系的TCID_(50)平均为4.02。对离乳幼犬的最低免疫剂量为5×10~(3·8)TCID_(50)。苗注后2周即可获得免疫,血清HI抗体达32即可抵抗CPV强毒感染。疫苗的免疫期为1年。于-15℃以下冰盒保存,疫苗的有效期为9个月。CR80106株遗传性稳定,经CPV易感幼犬和F81细胞系连续传5代和22代,对犬的安全性和免疫原性不变。病毒蛋白经SDS—PAGE和HPLC分析,均未发现与原始毒株有不同。M-CPV对母源抗体干扰有较强的抵抗力,母源抗体达32的幼犬,100％可对该亩产生免疫应答。HI抗体<2的CPV易感幼犬接种该苗后除粪便轻度阳转外,无其他异常,同居CPV易感幼犬也不会感染发病。两次免疫后作同居感染攻毒,可获得完全保护,不会由粪便排出强毒。于产前20d给怀孕母犬接种,也未见有流产、早产、死胎和弱胎现象发生,所产仔犬全部生长发育正常。全国16个军、警犬场队用本疫苗累计免疫各类犬3320只,全部安全,没有一只因注苗而发病,经1～2年临床观察,3296头获得保护,保护率为99.28％。 相似文献
7.
根据GenBank中犬腺病毒（canine adenovirus,CAV)纤突基因序列，设计合成2对引物。用PCR方法，对犬2型腺病毒沈阳分离株（CAV-2SY株）第5代强毒（SY-V5）、经蚀斑克隆驯化的第60代毒弱毒（SY-V60）、SY-V60感犬体上传5代的回收毒（SY-CP5）、美国疫苗毒（US-V20）等4个毒株的纤突基因进行了扩增，PCR产物经纯化后进行基因序列测定，测序结果经拼接后得到1个由1629个核苷酸组成的纤突蛋白全基因序列，编码543个氨基酸。犬2型腺病毒与GenBank中的标准的CAV-2强毒株（Toronto A26/61)纤突蛋白基因序列的比较结果表明：CAV-2SY株强毒株与Tornto A26/61株相同；SY-V60株与SY-CP5相同，与驯化前的SY-V5相比，在1134位发生碱基颠换，编码的氨基酸由原来的天冬酰氨（N）变为赖氨酸（K），并导致N-X-S/T潜在糖基化位点发生改变，US-V20该部位与发生同样的突变，本试测定和比较的CAV-2强毒株有5个潜在的N-联糖基化位点，弱毒株仅有4个位点；US-V20与TorontoA26/61差异较大，有11个碱基发生变化，导致8个氨基酸的变异。 相似文献
8.
《中国兽医学报》2020,(10)
为了获得犬细小病毒(CPV)变异株的致弱疫苗株,将CPV-2a野毒株(YZ10-5)在FK81细胞上连续传代,评价不同代次毒种对易感幼犬的毒力。用高代次传代毒种免疫高母源抗体(MDA)幼犬,经CPV-2a和CPV-2b强毒攻毒,评价致弱株的免疫保护效力。结果表明,CPV-2a毒株(YZ10-5株)在FK81细胞上连续传至31代,毒力明显减弱,传至61代无明显毒力。用61代致弱毒种(YZ10-5/F61),2×10~3TCID_(50)/剂,间隔3周,2次皮下注射接种高母源抗体幼犬,第2次免疫后3周用CPV-2a和2b变异株口鼻攻毒,所有免疫犬无明显临床症状,且粪便无排毒,而未免疫犬全部发病和粪便排毒。初步研究表明, CPV-2a传代致弱毒株(YZ10-5/F61)有希望用于开发CPV防控的新型疫苗。 相似文献
9.
将分离的一株DHv—Ⅰ野毒株经鸡胚传代,培育出DHV—Ⅰ的80代鸡胚致弱毒GFS99株。该弱毒株对1日龄雏鸭无致病性;在雏鸭体内连续盲传5代,也未出现毒力返强现象;1日龄雏鸭免疫100倍稀释的尿囊液弱毒GFS99后7天攻强毒GQY07株,保护率高达100％,且7日龄时即可产生高峰期中和抗体,后抗体效价有所下降,但易感期的3周内抗体保持较高水平;另外该弱毒的外源病原检验结果均为阴性和特异性实验结果良好。综上述结果表明,该弱毒GFS99株无外源病毒污染、特异性强、安全性好、遗传性稳定、免疫原性强,可以作为制备DHV—Ⅰ弱毒疫苗的候选株。 相似文献
10.
雏鹅新型病毒性肠炎病毒弱毒株的培育及其特性研究 总被引：1，自引：0，他引：1
应用在鸭胚成纤维细胞上连续传代的方法，获得了由雏鹅新型病毒性肠炎病毒强毒株（NGVEV－CN株）致弱的弱毒株（CN40株）。该弱毒株TCID50为10^-8.083，具有良好的安全性和稳定性，在易感1日龄雏鹅连传8代不返强。该弱毒具有良好的免疫原性，最小免疫剂量为10000TCID50，免疫后3d产生部分免疫力，5d产生坚强免疫力。口服免疫效果最好，对雏鹅免疫期在30d以上。该弱毒株能够干扰强毒在雏鹅体内繁殖，进入鹅体后能够进行一定程度繁殖并排泄出体外，使同居雏鹅感染并获得一定程度免疫力。临床使用后可极显著降低雏鹅的死亡率。 相似文献
11.
犬2型腺病毒SY株的致弱驯化 总被引：1，自引：1，他引：0
作者对分离和系统鉴定的一株犬传染性喉气管炎病毒（犬2型腺病毒）SY（沈阳）株，用犬肾传代细胞MDCK进行了致弱驯化，每驯化15代做一次初步的犬的安全性试验。用大剂量不同代次病毒对易感犬进行人工感染试验，每天观察犬的临床症状及白细胞总数，并于接毒后的第5d安乐死，作病理解剖学和病理组织学检查，易感犬的感染试验结果表明，SY株在犬贤细胞上传15代时对犬的致病力已降低，30代时对犬已不引起发烧，精神沉郁和厌食等症状，仅引起轻度的鼻炎，中度的咽炎，剖检肺表现正常，仅见支气管淋巴结肿大，45代时无临床症状，剖检除扁桃体肿大外没有见到其它症状，60代毒已完全失去致病力，未见任何临床症状及病理变化。 相似文献
12.
用PCR技术鉴定犬传染性肝炎病毒强、弱毒株的研究 总被引：1，自引：0，他引：1
根据Genebank中发表的犬传染性肝炎病毒 (ICHV)标准强毒株Glaxo和人工驯化的弱毒疫苗株CLL的保守序列间大小不同 ,按照引物设计的原则 ,设计合成了一对通用引物。该对引物可由ICHV强毒株扩增出 569bp的片段 ,而弱毒株可扩增出 2 4 4bp的片段。对PCR产物分别进行电泳、酶切和测序 ,证明PCR产物片段大小、酶切位点和核苷酸序列与设计的产物完全一致。正常DK细胞上清和犬传染性喉气管炎病毒 (CAV 2 )强、弱毒株细胞培养物均不能被该引物扩增 ,说明具有良好的特异性。其检测到的病毒量分别为 1 5TCID50 、 31TCID50 、说明该技术具有很高的敏感性。可用于ICHV强、弱毒株的鉴定和ICH的诊断 相似文献
13.
马传染性贫血病毒疫苗致弱过程中不同代次毒株LTR序列变异 总被引：2，自引：2，他引：2
有研究认为病毒基因组长末端重复序列LTR与病毒的毒力和复制能力直接相关.中国马传染性贫血弱毒疫苗是由一株高致病力毒株经体外白细胞传代而致弱的疫苗.经过体外超过110代传代后,病毒丧失了对马高致死性毒力并保持了良好的免疫原性.本文对传代过程中的不同代次病毒基因LTR进行了克隆和序列测定,发现传代过程中LTR发生了一系列明确的变异,一是转录起始位点在64代之前均以GGAC为特征,64代之后则表现为不规律的GAAC,AAAC,AGAC或GGTC;二是TAR起始碱基在59代之前多数为A,而64代之后均为G;三是在45代之后(55代除外),poly(A)附加位点一致表现为AA,这种一致的核苷酸变化均发生在毒力明显降低的代次,提示这些突变引起的位点或结构变化很可能与病毒毒力减弱有直接关系. 相似文献
14.
从北京某鸡场发生疑似鸡传染性贫血病毒(CAV)感染的鸡只病料中分离到了一株CAV,通过PCR和全基因组测序等方法对其进行了鉴定,命名为AV1550。将其全基因组序列与NCBI上的参考毒株序列进行同源性比对和进化分析,结果显示AV1550株与CAV参考毒株的同源性在91.7%~99.7%,与中国分离株LN15170的亲缘关系最近。VP1序列分析表明AV1550在75、89、125、141和394位氨基酸均为强毒株特征。1日龄SPF鸡经胸部肌肉途径接种含10000 EID50的AV1550病毒液后,接种鸡只出现明显的贫血症状,增长迟缓,死亡率高达50%,表明AV1550是一株具有较强致病性的CAV野毒株。 相似文献
15.
Immunity to canine adenovirus respiratory disease: effect of vaccination with an inactivated vaccine
H J Cornwell S D Paterson I A McCandlish H Thompson N G Wright 《The Veterinary record》1983,113(22):509-512
Nine puppies without maternal antibody to canine adenovirus (CAV) were divided into two groups. The first consisted of six puppies, each of which was given two doses of a commercial inactivated CAV-1 vaccine, 14 days apart. Eight days after administration of the second dose of vaccine, all six puppies, together with the second group, consisting of three unvaccinated controls, were challenged with an aerosol of virulent CAV-2. One dog from each group was killed on the third, fifth and 10th days after challenge and the three additional vaccinates killed at intervening times. All of the dogs developed respiratory signs, mainly coughing and tachypnoea, but the vaccinated dogs made a more rapid recovery. The lungs of both groups were consolidated, the areas affected being more extensive in the controls, and histological examination revealed the main lesion to be a severe necrotising bronchiolitis. Virus was isolated from the respiratory tissues and from throat swabs collected from both groups of dogs. The presence of neutralising antibody in the serum was not, of itself, sufficient to control viral replication and oblate the disease. 相似文献
16.
Induction of strong protection by vaccination with partially attenuated serotype 1 Marek's disease viruses 总被引：3，自引：0，他引：3
Witter RL 《Avian diseases》2002,46(4):925-937
Studies were conducted to better understand the relationship among Marcek's disease (MD) vaccine strains between induction of protective immunity and the degree of attenuation (or virulence). To obtain viruses at different stages of attenuation, very virulent plus MD strains 584A and 648A and selected clones of these strains were serially passaged in chicken and duck cells. These viruses were considered fully attenuated after passage for 70-100 times in chicken embryo cell cultures until they no longer induced gross lesions in susceptible, maternal antibody-negative (ab-) chickens. Lower passages of the same strains were considered partially attenuated, provided their virulence was less than that of the parent strain. Four of five partially attenuated preparations derived from MD virus strains 584A and 648A or the previously attenuated Md11 strain induced 28%-62% higher levels of protection in maternal antibody-positive (ab+) chickens against virulent MD challenge than the fully attenuated counterpart viruses. The partially attenuated 584A/d2/3 strain replicated in chickens but was totally nonprotective. Data from two subsequent trials in ab+ chickens confirmed that protection induced by the partly attenuated (passage 80) preparations was 79% and 118% higher, respectively, than that induced by the fully attenuated (passage 100) preparations of strain 648A. However, in one trial with ab- chickens, no difference in protection between partially and fully attenuated virus was observed. Strong protection (up to 85%) against highly virulent challenge also was provided by preparations of 648A at passages 40-60, which were moderately oncogenic when used alone. Partially attenuated strains tended to replicate to higher titers in both ab+ and ab- chickens compared with fully attenuated vaccines. Also, ab+ and ab- chickens vaccinated with partially attenuated strains developed three- to nine fold more extensive microscopic lesions in peripheral nerves at 14 and 22 days after virulent challenge than chickens vaccinated with fully attenuated strains. When measured in ab+ chickens, loss of lesion induction by 648A was achieved 30 passages earlier (at passage 70) than when measured in ab- chickens. Thus, maternal antibodies appeared to abrogate the pathogenicity of some partially attenuated strains. These studies establish for MD the principle that at least some partially attenuated MD viruses may replicate better and induce stronger immunity against virulent challenge than fully attenuated preparations of the same strain, at least when tested in ab+ chickens. Moreover, depending on passage level, partially attenuated vaccine strains may be relatively innocuous for ab+ chickens, causing few or no lesions. 相似文献
17.
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
18.
本试验分离获得了1株巨型艾美耳球虫，通过紫外线诱导和非紫外线诱导两种方法对该虫株进行早熟选育，获得了2个巨型艾美耳球虫早熟减毒株。通过对2个早熟株的潜隐期、繁殖力、致病力以及免疫原性进行对比研究，证明紫外线诱导下的早熟选育可明显缩短选育所需代数，且与传统方法选育的早熟株在繁殖力、免疫原性与免疫保护力等方面基本相同。紫外线诱导下，经7代早熟选育，潜隐期由母株的142h缩短到116h，而非紫外线诱导的选育需要20代才能达到同样的选育结果。两早熟株卵囊的繁殖能力与母株相比有所下降，但仍保留了母株原有的免疫原性。 相似文献
19.
利用Vero-DST细胞从死亡犬、狐狸肺、脾内分离到4株犬瘟热病毒-CDV-TM-CC、CDV-Dog-SCh、CDV-Fox-SY、CDV-Fox-WF,在Vero-DST细胞上传5代没有细胞病变,5代细胞培养物经电镜、间接免疫荧光及PCR鉴定为阳性。与本实验室保存的CDV-Monkey-BJ进行基因测序,并对与致病相关的F蛋白、V蛋白进行分析,F蛋白分析5株毒具有6个潜在N-末端糖基化位点,与强毒株同源性在92%～99.7%,与疫苗株不高于93.3%,在F1亚基内有7个特有氨基酸位点,这可能与其对灵长类致病有关。V蛋白分析表明,其与强毒株同源性在94%～99.7%之间,而与疫苗株不高于93.3%,CDV-Monkey-BJ C272R突变使其Zn结合能力丧失。试验结果显示,所有分离株均为强毒株,不同宿主毒株序列存在差异,值得进一步研究。 相似文献
20.
H Poulet P M Guigal M Soulier V Leroy G Fayet J Minke G Chappuis Merial 《The Veterinary record》2001,148(22):691-695
Six bitches free of canine herpesvirus 1 (CHV-1) were vaccinated against the virus; a first injection was given 10 days after the presumed date of mating and a second six weeks later. Six similar bitches were left unvaccinated as controls, and all the pups were challenged oronasally with a virulent strain of CHV-1 at three days of age. All the vaccinated bitches seroconverted and had high antibody titres when the puppies were challenged, but the control bitches remained seronegative. In the control group, 62 per cent (18 of 29) of the pups died of CHV-1-induced disease; most of them showed typical clinical signs and macroscopic lesions, and CHV-1 infection was confirmed by the isolation of the virus or by PCR. None of the puppies in the vaccinated group died of CHV-1 infection. The efficacy of the vaccine was confirmed in CHV-1-positive breeding units. The rate of pregnancy tended to be higher in vaccinated bitches and the mortality of pups before weaning was significantly reduced in the litters born to vaccinated bitches. 相似文献