本研究将鸡传染性法氏囊病超强毒(vvIBDV)SD0210株经SPF鸡胚培育及鸡胚成纤维细胞(CEF)传代培养,获得了对CEF适应的细胞毒,并对细胞毒进行了致病性、回归动物的稳定性试验及免疫原性方面的试验,结果表明已成功获得了具有髙免疫原性且安全无毒力返强的致弱株,并初步揭示了vvIBDV在适应细胞、从超强毒力向弱毒力转化过程中,VP2高变区氨基酸序列的变化情况。SD0210株培养至18代开始适应细胞,出现细胞病变。21代细胞毒已对SPF鸡失去了致病性,在鸡体内连续传代15代毒力不返强,而且具有较高的免疫原性。

A very virulent strain SD0210 of Infectious bursal disease virus (vvIBDV) was adapted to chicken embryo fibroblast cell (CEF) after propagating in SPF chicken embryo for 10 generations and CEF for 18 generations. The test of pathogenicity, virulent stability and immunogenicity in chickens showed that the cell-adapted virus kept the immunogenicity of paternal virus, while its virulence did not reverse. The change pattern of deduced amino acid sequences in VP2 hypervariable region during the adaptation to CEF and transform from high pathogenicity to low pathogenicity has been obtained. When the virus was passed to the 18th generation, it began to adapt CEF and cause cell pathological effect (CPE). To 21th generation, the virus still kept its paternal immunogenicity and had no pathogenicity to SPF chickens even it was propagated to 15th generation in SPF chicken bodies.