一株自然基因重排鸡传染性法氏囊病病毒的分离鉴定及其分子特征分析

Isolation of Infectious Bursal Disease Virus and Characterization of its Genome

研究通过鸡胚绒毛尿囊膜(CAM)接种SPF鸡胚的方法从可疑鸡群的法氏囊样品中分离获得了1株鸡传染性法氏囊病病毒(infectious bursal disease,IBDV),命名为YY1213。基于IBDV基因组A节段的VP2基因高变区(vVP2)和B节段的VP1-b区的序列测定和分析表明,分离株YY1213在vVP2上的关键氨基酸特征与vvIBDV类似,并与vvIBDV参考株具有较高的同源性,但在VP1-b上的特征性氨基酸位点则既有弱毒株的特征,又具有vvIBDV的特征,与中国内地分离株重组毒株HLJ-0504的同源性较高,氨基酸同源性达到了99.6%;此外,在遗传进化分析上,基于vVP2,YY1213与vvIBDV高度同源,而基于VP1-b,则介于vvIBDV和弱毒株之间,形成独特分支。结果表明,分离株YY1213的vVP2和VP1-b具有不同的来源,属于基因重排病毒。

An infectious bursal disease virus（IBDV isolate YY1213） was isolated from the IBD suspected chicken flock by chicken embryo inoculation of the Fabricus＇ bursa suspension via chorio-allantoic membrane（CAM）. The sequence analysis of VP2 hypervariable region（vVP2） from IBDV genome segment A indicated that, the isolate was classified to be potent virulent IBDV（vvIBDV） according to critical amino acid sequences and showed the highest similarity to reference strains of vvIBDV. But when the sequence analysis of VP1-b fragment from IBDV genome segment B was done, the isolate showed mixed characteristic amino acid sites, some of these sites were similar to vvIBDV, others were similar to attenuated IBDVs, and showed 99.6% homology to a Chinese reassortant strain HLJ-0504. Furthermore, in the phylogenetic analysis, YY1213 was grouped with vvIBDV reference strains based on vVP2, however it was showed an independent cluster between vvIBDV and classical strains when based on VP1-b. These results suggested that genomic fragments A-vVP2 and B-VP1-b of the isolate YY1213 were of different origins, and YY1213 seems to be a reassortment virus.