染性法氏囊病病毒分离株变异的研究

为了了解我国传染性法氏囊病病毒(IBDV)的变异现状,并为研究高效疫苗打下基础,用琼脂糖凝胶电泳,SDS-PAGE和序列分析等分子生物学方法，分析IBDV病毒RNA，结构蛋白的变异情况。结果表明⑴3种不同源IBDV均由双节段RNA组成，大小基因片段的电泳迁移率各病毒间无差异；⑵不同源IBDV的结构蛋白带谱相同，但各蛋白带的百分含量有差异；⑶IBDV血清Ⅰ型不同亚型的JS3和JS4毒株主要保护性抗原VP2高变区核酸序列的同源性最高达98%，与已发表的vvIBDV，IBDV变异株，IBDV经典株及IBDV弱毒株核苷酸序列同源性在92%～98%之间。根据IBDV的大开放读框推导出该片段编码蛋白的氨基酸序列，JS3和JS4的同源性最高达97%，与上述其它毒株的同源性在91%～97%之间；七肽区的氨基酸序列，在强毒株完全相同，而在弱毒株有一个丝氨酸突变成其它氨基酸。

Study on the Variation of Infectious Bursal Disease Virus (IBDV)

Abstract　Variation status of virus RNA and structural protein were analyzed wit h agarose electropxhoresis,SDS-PAGE and sequence analysis. Results: (1) IBDV of t hree different source consists of two fragments, the rates of RNA migration of l arge and small fragments in agarose gels were of no difference for different str ains. (2)Analysis of IBDV by SDS-PAGE showed the same spectrum of structural p ro tein, but the relative percentage contents were different. (3) The homology of t he sequences of JS3 and JS4 was 98%.The identity of JS3 and JS4 with vvIBDV, va r iant IBDV, classical IBDV and attenuated IBDV published in GenBank databases ran ged from 92% to 98%. The homology of the deduced amino acid sequences based on th e ORF of JS3 and JS4 was 97%. The identity of JS3 and JS4 with above strains va r ied from 91% to 97%. The heptapeptide of IBDV was highly conserved in virulent strains, but mutated in attenuated strains.