将从山东省东营分离到的1株传染性法氏囊病病毒(IBDV)野毒(暂命名IBDV SDDY株,经鉴定该株与IB DV STC株具有较高的同源性)经SPF 鸡胚传代,然后转为细胞培养,取第20 代、21 代、25 代毒,以1 倍剂量(3000TCID50/0.2mL )和5倍剂量不同的免疫剂量,分别在7日龄、14日龄对商品代海蓝褐蛋鸡进行免疫,并于免疫前用IBD ELISA试剂盒检测IBDV母源抗体水平,于35 日龄用传染性法氏囊病病毒超强毒(very virulent In fectious Bursal Disease Virus, vvIBDV )GX 8/99攻毒,在攻毒前再次检测IBDV的抗体水平,攻毒后观察记录各分组鸡的致病率和死亡率,并计算免疫器官体重指数,观察免疫器官的组织损伤情况。试验结果表明:3 代毒都具有较高免疫原性,但是20代毒仍具有较大的毒性,7 日龄接种会引起法氏囊的萎缩,造成持续的组织损伤;21 代毒、25代毒保护率高,无免疫抑制,是比较理想的疫苗来源;7日龄免疫较14日龄免疫更易造成组织损伤和免疫抑制,14日龄免疫较为合适。

An infectious bursal disease virus (IBDV), isolated from Dongying city in Shandong province, was propagated several generations in SPF embryos and then turned to cell culture. The chickens were immunized by 20th, 21st, and 25th generation cell viruses in different doses at the age of 7 d and 14 d, and then were challenged at the age of 35 d. The titers of antibody to IBDV were detected before inoculation and challenge. According to the titers of antibody against IBDV after inoculation, the morbidity and mortality after challenge, the ratios of immune organ to body weight, the damage of immune organ, the results demonstrated that all the viruses had good immunogenicity when the chickens were vaccinated at 14d with the dose of 3000TCID\-(50) by the primary vaccine, and the chickens gained better immune protection. The 20th generation had durative pathogenicity to chickens when inoculated at 7d and caused immunosuppression to ND immune responses while 21st and 25th had transitory tissue damnification and immunos