CAJ | 학술논문

将两株鸡传染性法氏囊病病毒（ IBDV）弱毒株在SPF鸡体内连续传代至第5、第6代时，出现明显的法氏囊萎缩和B ∶ B指数下降，表明IBDV弱毒株在鸡体内连续传代后毒力增强。为进一步阐释哪些基因位点导致了上述毒力的变化，本试验测定了基础弱毒株及其在鸡体内传代后各个代次毒的基因组序列，比对分析后发现VP 2蛋白253位氨基酸发生了由H到Q或N的变异，表明VP 2蛋白253位氨基酸的替换可能会增强传染性法氏囊病病毒在鸡体内的致病性。
장량주계전염성법씨낭병병독（ IBDV）약독주재SPF계체내련속전대지제5、제6대시，출현명현적법씨낭위축화B ∶ B지수하강，표명IBDV약독주재계체내련속전대후독력증강。위진일보천석나사기인위점도치료상술독력적변화，본시험측정료기출약독주급기재계체내전대후각개대차독적기인조서렬，비대분석후발현VP 2단백253위안기산발생료유H도Q혹N적변이，표명VP 2단백253위안기산적체환가능회증강전염성법씨낭병병독재계체내적치병성。
Two attenuated IBDV strains were passaged five or six times in SPF chickens. Both attenuated strains increased in virulence during the passage in susceptible chickens as evidenced by the decrease in bursa/body weight ratios and B ∶ B index. In order to further explain which animo acids result in the change of virulence, sequences of the genome of the attenuated IBDV strains and the passage strains in chickens were amplified and analyzed. The results showed that an amino acid mutated from Histidine( H) to Glutamine( Q) or Asparagine( N) at position 253 in VP2 during the passage in chickens. Together ,the pathogenicity and molecular data indicate that a single amino acid substitution at position 253 in VP2 increases the pathogenicity of IBDV in vivo.