摘要
分别以传染性法氏囊病病毒 ( IBDV) X毒株细胞适应的第 5代、第 1 1代和第 1 7代毒感染 38日龄非免疫雏鸡进行致病性试验 ,确定 X毒株的毒力 ,并比较 3个代次毒的致病性差异 ,进而利用 RT-PCR扩增其VP2 基因可变区 ,测定其核苷酸序列 ,从分子生态学角度研究了非鸡胚源细胞传代培养对 IBDV X毒株毒力和抗原性的影响。结果表明 ,IBDV X毒株表现为中等毒力 ,在 Vero细胞上传代后 ,其毒力有所减弱。VP2 可变区氨基酸序列有 3个位置发生了替换 ,即第 5代毒氨基酸残基 2 62位为半胱氨酸 ,而第 1 1代毒和第 1 7代毒则变为酪氨酸 ( Cys→ Tyr) ;第 5代毒的 2 90位为缬氨酸 ,而第 1 1代和第 1 7代毒则变为蛋氨酸 ( Val→Met) ;第 5代毒和第 1 1代毒的 31 6位为赖氨酸 ,而第 1 7代毒则变为精氨酸 ( Lys→Arg)。 2 90位氨基酸替换导致该区域二级结构的改变 ,并对 IBDV的抗原性有显著影响。上述结果提示 ,这些氨基酸残基可能对维持IBDV的毒力和抗原性是必要的。通过毒株间 VP2 可变区序列的比较和系统发生树的分析 ,证明 IBDV X毒株与 Bursin-2疫苗毒关系很近。
The virulences of cell adapted strain X of infectious bursal disease virus (IBDV) were determined by infecting non immuned chicken with the 5th,11th and 17th passages of IBDV strain X,and their pathogenicities were furtherly compared with IBDV D 78 strain.The cDNA fragments of the variable region of VP 2 gene were amplified by reverse transcriptase polymerase chain reaction(RT PCR).The nucleotide sequence was determined,and the change of nucleotide and amino acid sequence was analyzed to ascertain the influence of cell culture passage on the virulence and antigenicity of strain X.The result showed that after being passaged on vero cells,its pathogenicity became weak.There are three amino acid substitutions:amino acid residue at position 262 changed from cysteine(5th passage virus) to Tyrosine(17th passage virus)、290(Val→Met) and 316(Lys→Arg),the substitution of amino acid residue at 290 results in the change of secondary structure at this region,and has great effect on the antigenicity of strain X.The results above implied these amino acid residues may be necessary for maintaining the virulence and antigenicity of IBDV.It is demonstrated that strain X evolve closely with intermediate vaccine Bursine 2 by comparison and phylogenetic analysis of the sequence of variable region of VP 2 gene between strains.
出处
《中国兽医学报》
CAS
CSCD
北大核心
2001年第1期1-5,共5页
Chinese Journal of Veterinary Science
基金
陕西省科委攻关项目! (95 K0 2 -G1 -0 1)
关键词
传染性法氏囊病病毒
X毒株
致病性
VP2可变区
序列分析
infectious bursal disease virus
cell adapted strain X
pathogenicity
VP 2 variable region
sequence analysis
