传染性法氏囊病重组亚单位疫苗保存期试验

Experiment in the Conservative Period of Recombinant Subunit Vaccine for Infectious Bursal Disease

将14日龄SPF鸡分为5组，A、B和C组分别接种保存期为20、340、370d的传染性法氏囊病重组亚单位疫苗，D和E组不接种。35日龄时，对A、B、C、D组的鸡以100倍法氏囊感染剂量的标准强毒株IBDV BC-6／85进行滴鼻。攻毒后第4天，将所有鸡致死，进行剖检，观察法氏囊眼观病变，取法氏囊组织以琼脂免疫扩散试验检测传染性法氏囊病毒抗原。法氏囊未见到明显肿大、变黄或胶冻样渗出物或出血等眼观病变及法氏囊中传染性法氏囊病毒抗原检测阴性判定为受到免疫保护。将各组的试验数据以X^2检验进行统计分析。结果，A、B、C、D组的免疫保护率差别具有统计学意义，A与D组、B与D组、C与D组之间的免疫保护率具有极显著差异。结果表明，在2～8℃保存1年该疫苗的稳定性和免疫原性仍然相当好。

14-day-old chickens with specific pathogen free（SPF）were divided into 5 groups. 3 groups （A, B and C ） were intramuscularly injected with recombinant subunit vaccine that been conserved for 20 days, 340 days and 370 days for infectious bursal disease（IBD） respectively; and chickens of group D and E were not intramuscularly injected. At the age of 35 days chickens of 4 groups （A, B, C and D） were infected with the nose-drop route with standard challenge virulent strain of IBDV BC-6/85 at the dosage of 100 times as much as bursal infectious dose. On 4th day of infection all chickens were killed and the visible pathological changes of bursa Fabricii were examined with the naked eyes. The bursa Fabricii were taken and IBDV antigen was tested in all their bursas with agar gel immune-diffusion test（AGID）. Immune protection was evaluated with two judging indexes that remarkable tumescence and xanthochromia or colloidal exudant or hemorrhage were not seen and IBDV antigen was negative in bursa Fabricii. All data were analyzed with x^2 test （Chi-square Test ）. The difference of percent of immune protection in 4 groups（ A, B, C and D） was statistical significance. The difference of percent of immune protection was very significance between group A and group D, between group B and group D, and between group C and group D. The experimental results showed that the stability and immunogenicity of the vaccine were good when the vaccine was conserved for a year at 2 - 8 %.