摘要
从辽宁省某鸡场疑似马立克氏病发病鸡外周血淋巴细胞中分离到1株适应鸭胚成纤维细胞生长的马立克氏病病毒(MDV),经蚀斑克隆和细胞传代,成功培育了1株增殖性能稳定的MDV细胞毒株,命名为HC135株;将HC135株第4代细胞培养物分别人工感染非免疫和不同疫苗免疫的SPF鸡,分析其对鸡的致病力,分离毒株攻毒对照组鸡的发病率为100%(10/10),死亡率为30%(3/10);HVT疫苗及HVT/SB1双价疫苗对分离毒株的保护指数分别为22.2和40.0。结果表明,该毒株可以突破HVT疫苗和HVT/SB1双价疫苗的免疫保护,具有特超强毒株(vv+MDV)的特点;也证实了我国商品鸡群中存在vv+MDV毒株。同时比较了HC135株与14株参考毒株的Meq基因序列,发现其Meq基因的ORF内没有基因片段的插入或缺失,推导的氨基酸存在点突变,这种突变符合高毒力毒株的变异规律。
Peripheral blood lymphocytes of the diseased chickens from commercial chicken flocks experienced significant Marek＇s disease visceral tumour in Liaoning Province were collected,and were inoculated into monolayer of duck embryo fibroblast.The isolated Marek＇s disease virus（MDV） was obtained by plaque clone,and named strain HC135.To examine the pathogenicity of this isolate,unvaccinated SPF chickens were challenged with strain HC135.Morbidity and mortality were 100%（10/10） and 30%（3/10）,respectively.HVT vaccine alone or combined with SB1 vaccine strains provided poor protection when the SPF chickens were challenged with this strain.Protection index was 22.2 and 40.0,respectively.Vaccination to chickens with HVT vaccine alone or combined with SB1 vaccine strains did not protect satisfactorily against the strain HC135.It had the characteristics of vv＋MDV strains,indicating the occurrence of vv＋MDV in Chinese commercial flocks.Meq gene nucleotide were determined and compared with 14 reference strains.The results showed that there was no nucleotide deletion or insertion in the ORF of the Meq gene of the isolate.But there were nucleotide mutations,and the nucleotide changes would lead to changes in the predicted amino acid sequences of the isolate.Their variations are corresponded to the high virulence MDV strains characteristic.
出处
《中国兽医科学》
CAS
CSCD
北大核心
2011年第3期240-244,共5页
Chinese Veterinary Science
基金
国家重点实验室基本科研业务费专项(SKLVBP201008)
中央级公益性科研院所基本科研业务费专项(1610302011002)
