Changes in VP3 and VP5 genes during the attenuation of the very virulent infectious bursal disease virus strain Gx isolated in China
Changes in VP3 and VP5 genes during the attenuation of the very virulent infectious bursal disease virus strain Gx isolated in China
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DOI：
10.1007/s11262-006-0002-y
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发表时间：
2006
期刊：
影响因子：
1.6
通讯作者：
Xiaomei Wang;Houshuang Zhang;Honglei Gao;C. Fu;Yulong Gao;Yulin Ju
中科院分区：
文献类型：
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作者：
Xiaomei Wang;Houshuang Zhang;Honglei Gao;C. Fu;Yulong Gao;Yulin Ju
通过在SPF鸡胚和鸡胚成纤维细胞中复制，使一株高致病性传染性法氏囊病病毒（IBDV）Gx株弱毒。获得了VP 3和VP 5基因在减毒过程中的核苷酸序列和推导的氨基酸序列变化。CEF中从0至20号的选定传代（此处指定为Gx至CEF-20）的序列分析显示，在CEF-9之前，在VP 3和VP 5基因中未检测到氨基酸变化。在CEF-9中，VP 3和VP 5基因的核苷酸序列和氨基酸替换发生了一些变化。CEF-9是一个中间体，其氨基酸发生了一些变化，可能与毒力有关。从CEF-10到CEF-20，VP 2和VP 5基因的氨基酸序列保持不变。致病性试验结果表明，vvIBDV-Gx、CEF-5、CEF-8和CEF-9的死亡率分别为64、60、60和28%，而CEF-10、CEF-15和CEF-20均未观察到死亡。当鸡接种CEF-10、CEF-15和CEF-20时，也没有法氏囊萎缩。用Gx株和接种鸡血清进行中和试验，结果表明Gx株的抗原性与CEF-20相似。这些研究结果的影响IBDV毒力的研究和更有效地控制vvIBDV进行了讨论。
A very virulent infectious bursal disease virus (vvIBDV) Gx strain with high pathogenicity was attenuated through replication in specific-pathogen free (SPF) chicken embryos and in chicken embryo fibroblast (CEF) cell cultures. The changes in nucleotide sequences and the deduced amino acid sequences of VP3 and VP5 genes during attenuation were obtained. Sequence analysis of selected passages from numbers 0 to 20 in CEF’s (designated here Gx to CEF-20) showed that there were no amino acid changes detected in the VP3 and VP5 genes before CEF-9. There were some changes in the nucleotide sequence and amino acid substitutions in the VP3 and VP5 genes at CEF-9. CEF-9 was an intermediate with some amino acid changes which were possibly related to virulence. The amino acid sequences of VP2 and VP5 genes remained unchanged from CEF-10 to CEF-20. The results of pathogenicity test showed that the mortalities of vvIBDV-Gx, CEF-5, CEF-8, and CEF-9 were 64, 60, 60, and 28%, respectively, while there were no mortalities observed for CEF-10, CEF-15 and CEF-20. There was also no bursal atrophy when chickens were inoculated with CEF-10, CEF-15, and CEF-20. Virus neutralization tests with the Gx strain and sera from inoculated chickens showed that the antigenicity was similar from Gx to CEF-20. The implications of these findings for the study of IBDV virulence and a more effective control of vvIBDV are discussed.