家蚕表达传染性法氏囊病病毒VP2蛋白的免疫原性初步研究(英文)

Study on the Immunogenicity of Infectious Bursal Disease Virus VP2 proteins Expressed in Silkworm

在家蚕培养细胞及幼蚕中表达传染性法氏囊病病毒 ( IBDV)主要宿主保护性抗原 VP2蛋白的基础上 ,初步研究了该表达产物的免疫原性 .Western免疫印迹和 ELISA均检测到春蚕和秋蚕中的 VP2蛋白活性 .含 VP2的春蚕蚕血制成的注射疫苗皮下注射 18日龄非免疫鸡 ,两周后二免 ;含 VP2的秋蚕蚕血冻干制成口服疫苗 ,隔天喂服 18日龄非免疫鸡 .于首免后第 10 ,13,2 1,2 8,37日分别采血 ,第 37日攻毒 .病毒血清中和试验显示注射组及口服组的中和抗体滴度最高可达 1∶ 42 11.3和 1∶ 3118.9,攻毒结果显示它们对 IBDV中国标准强毒株 BC6/85的攻击保护率为 10 0 %和 80 %.以上研究表明家蚕表达的 VP2蛋白具有良好的免疫原性 ,从而为开发实用化低成本的疫苗打下了扎实基础 .

The VP2 protein of infectious bursal disease virus (IBDV) was expressed in spring and autumn silkworm larvae as detected by Western blot and ELISA. Non immunized 18 day old chickens were vaccinated via subcutaneous injection with a vaccine preparation made from the lymph of spring silkworms containing VP2 expression product. The boosting immunization was carried out two weeks later. The lymph of autumn silkworms was freeze dried as the oral vaccine. Non immunized 18 day old chickens were fed on the oral vaccine every other day. Serum samples from the immunized chickens were harvested. Virus neutralization (VN) test showed that the titers of VN antibody was 1∶4211.4 in the sera of chickens receiving subcutaneous immunization and 1∶3118.9 in those of chickens fed on oral vaccine at day 37 post immunization. The immunized chickens were challenged with BC6/85, a reference Chinese virulent IBDV strain at the 37th day after vaccination. The rate of protection against BC6/85 infection was 100% for the chickens with subcutaneous vaccination and 80% for those receiving oral vaccine. These results indicate that the VP2 protein expressed in silkworm larvae is immunogenic and the established expression system for VP2 has laid a firm basis for the development of practical yet low cost vaccines against infectious bursal disease.