超强传染性法氏囊病病毒株宿主保护抗原的分子特征  

Molecular Signature of Host protective Antigen of Highly Virulent Strains of Infectious Bursal Disease Virus

作　　者：曹永长[1] 毕英佐[1] 梁志清[2] 林文量[2] 

机构地区：[1]华南农业大学动物科学系 [2]香港大学动物学系

出　　处：《中国兽医学报》1998年第6期521-526,共6页Chinese Journal of Veterinary Science

基　　金：国家攀登计划;香港政府工业署工业支援基金

摘　　要：为了探索超强传染性法氏囊病病毒（ＩＢＤＶ）株毒力增强的原因，采用反转录－聚合酶链反应技术，从中国广东、福建分离到的３株超强ＩＢＤＶ毒株中扩增到编码ＶＰ２蛋白的ｃＤＮＡ基因片段，并对ＶＰ２基因的高可变区进行了序列测定。序列分析和聚类分析表明，３株超强毒株与欧洲超强毒株非常相似，而与经典强毒株、弱毒株和变异株相差较大。将超强毒株ＶＰ２高可变区的氨基酸序列与其他血清Ⅰ型毒株进行比较，发现除了具有一般ＩＢＤＶ强毒株的分子特征之外，所有超强毒株在２２２、２５６、２９４和２９９位上的氨基酸均相同，分别为Ａ、Ⅰ、Ⅰ和Ｓ，与其他毒株均不相同。而２２２、２９４和２９９位上的特征性氨基酸使超强毒株ＶＰ２中诱导中和抗体的抗原决定簇的构象发生细微变化，从而导致毒力增强。To elucidate why does the virulence of the highly virulent strain of infectious bursal disease virus (IBDV) increase, the cDNA fragments coding host protective antigen VP2 were amplified from three Chinese highly virulent (HV) isolates of IBDV using reverse transcription polymerase chain reaction (RT PCR), and the nucleotide sequences of variable region of VP2 determined from the cDNA fragments using autocycle PCR. Sequence and cluster analysis shows that three Chinese HV IBDV strains are closely related to each other and to European HV IBV strains than to other serotype Ⅰstrains. Comparison of deduced amino acid sequences of variable region of VP2 of HV strains with that of other serotype Ⅰstrains shows that HV strains share identical residues A, I, I and S at positions 222, 256, 294 and 299 respectively which differ from other strains, besides the molecular properties of classical virulent IBDV. It is suggested that those particular amino acid substitutions raise the subtle changes of comformational nature of the immunogenic sites which may be responsible for inducing production of neutralization antibody, leading increase of virulence of HV IBDV strains.

关 键 词：传染性 法氏囊病病毒 超强毒株 宿主保护抗原 

分 类 号：S852.65[农业科学—基础兽医学]