两株马立克病病毒的分离及相关致病基因序列的比较

Isolation and identification of two Marek's disease virus strains and sequence comparison of genes involved in pathogenesis between the two strains

为了解国内鸡群马立克病（MD）流行毒株的遗传特征,采用细胞培养、间接免疫荧光等方法从江苏省2个鸡场送检病鸡中分离鉴定出2株马立克病病毒（MDV）Ⅰ型毒株,采用PCR方法扩增两分离毒株的vIL-8、pp38、meq等病毒致病相关基因,所得序列用DNAStar软件与GenBank上登录的参考毒株进行比较分析。结果显示,两分离毒株的序列同源性为99.7%-100%,与MDVⅠ型强毒及超强毒株的同源性为99.3%-99.8%,具有强毒特征;两分离毒株的meq基因与其他4个国内分离强毒株的序列完全一致,在pp38基因编码的氨基酸序列中第109位均为甘氨酸而不是国外GA等毒株的谷氨酸,这与以前报道的另外3个中国野毒株一致。提示,这些变异可能是国内MDV流行强毒的遗传性特征。

To investigate genetic characteristics of Marek＇s disease virus（MDV） prevalent in China, cell culture and indirect immunofluorescenee assay were applied to isolate MDV and identify its serotype. Genes involved in pathogenesis of MDV,such as vIL-8, pp38 and meq were amplified by polymerase chain reaction（PCR）. The obtained sequences were compared with that of standard strains published in Gen- Bank. The results suggested that two strains of MDV serotype 1 were isolated. They shared homology from 99.7% to 100% with each other,and from 99.3% to 99.8% with that of standard virulent MDV-1 and very virulent MDV 1. Meq genes of the two strains were completely identical with that of the other four Chinese field virulent strains. Moreover, amino acid residue at site 109 of pp38 of the two isolates was glycine instead of glutamine of GA strain, which was consistent to that of the other three Chinese field isolates. These variances might be genetic characteristics of MDV prevalent in China.