鸡传染性法氏囊病病毒野毒株VP2基因高可变区酶切位点分析

Analysis on VP2 Hypervariable Region of Five IBDV Isolates using the RT-PCR/RE Assay

参照澳大利亚鸡传染性法氏囊病病毒（ Ｉ Ｂ Ｄ Ｖ）００２７３ 毒株基因组序列设计的 １ 对引物，位于 Ｖ Ｐ２ 高可变区两端，通过 Ｒ Ｔ Ｐ Ｃ Ｒ，扩增了 ５ 个 Ｉ Ｂ Ｄ Ｖ 山东分离株 Ｖ Ｐ２ 基因的 ６０７～１ ０８０ 位核苷酸片段（ａａ２０３～３０６）。 Ｐ Ｃ Ｒ 产物经纯化后，分别用 Ｄｒａ Ⅰ、 Ｓａｃ Ⅰ、 Ｓｓｐ Ⅰ、 Ｐｓｔ Ⅰ和 Ｓａｕ３ Ａ Ｉ共 ５ 种限制性内切酶（ Ｒ Ｅ）进行消化处理，结果 ５ 个分离株均为 Ｄｒａ Ⅰ（－ ）、 Ｓａｃ Ⅰ（－ ）和 Ｓａｕ ３ Ａ Ｉ（＋ ）， Ｌ Ｃ２ 和 Ｔ Ａ 株为 Ｓｓｐ Ⅰ（＋ ）， Ｌ Ｃ１ 和 Ｊ Ｎ 株为 Ｓｓｐ Ⅰ（－ ）， Ｌ Ｃ１ 和 Ｌ Ｃ２ 株为 Ｐｓｔ Ⅰ（＋ ）， Ｊ Ｎ、 Ｌ Ｌ 和 Ｔ Ａ 株为 Ｐｓｔ Ⅰ（－ ）；５ 个分离株的酶切图谱与美国变异株迥异，而 Ｔ Ａ 株与日本超强毒株 ９０１１ 相类似。５ 个分离株与现用疫苗株对比，至少在 Ｖ Ｐ２ 可变区内存在着一定的差异，这可能是 Ｉ Ｂ Ｄ Ｖ 接种免疫鸡群仍然暴发 Ｉ Ｂ Ｄ 的原因之一。

The 607 1 080(nucleotide residue) region in VP2 gene of each isolate was amplified using RT PCR, with primer 1 and primer 2 lied in the each end of hypervariable region of VP2 gene respectively. The PCR products were purified and then digested with restriction enzyme DraⅠ, SacⅠ, SspⅠ, PstⅠ and Sau3A I. As a result, five isolates are all DraⅠ(-), SacⅠ(-) and Sau3A I (+); LC 2 and TA are SspⅠ(+) while LC 1 and JN are SspⅠ(-); LC 1 and LC 2 are PstⅠ(+) while JN LL and TA are PstⅠ(-). Furthermore, LL and TA were similar to vvIBDV 90 11. The differences between these five isolates and vaccine strains were significant, which expressed that the field strains in Shandong province were extincted from vaccine strains at least in the hypervariable region. Those maybe explain why the IBDV field strains can still epidemic in the immunized flocks.