鸡白细胞介素2增强传染性法氏囊病病毒多聚蛋白DNA疫苗免疫原性的研究

鸡白细胞介素 2(IL-2)基因是新近被确定的非哺乳类IL-2基因。将鸡白细胞介素2(IL-2)基因和传染性法氏囊病病毒 (IBDV)多聚蛋白基因 (VP2/VP4/VP3)分别插入真核表达载体pCI的CMV启动子下游 ,制备DNA疫苗 ,免疫 14日龄SPF鸡 ,14d后二免 ,二免后 3d攻击标准强毒株。结果表明共注射鸡IL 2质粒能明显增强DNA疫苗对强毒攻击 ,保护率达 80 % ;能增强DNA疫苗诱导的中和抗体效价 (P<0.05 ) ;能显著促进鸡胸腺、脾脏和外周血液T淋巴细胞及法氏囊B淋巴细胞增殖反应(P<0.05)。这些结果提示鸡IL 2能明显增强IBDV多聚蛋白DNA疫苗的免疫原性 ,是一种优良的禽类DNA疫苗佐剂。

Enhanced Immunogenicity of Plasmid Encoding Polyprotein Gene of Infectious Bursal Disease Virus by Co-administration of Chicken Interleukin 2 (IL-2)

Chicken interleukin 2 (IL-2) is one of important nonmammalian cytokines isolated recently.The influencing of IL-2 on immunogenicity of DNA vaccine was examined using infectious bursal disease virus as a model.The IL-2 cDNA of Xiaoshan chicken and the polyprotein gene of IBDV-ZJ2000 were amplified by RT-PCR,cloned,sequenced and inserted into the control of CMV promoter and enhancer of pCI vector.14-day-old chickens were vaccinated intramuscularly with DNA vaccine,two weeks later,they were boosted with DNA,and two weeks post boost,they were challenged with virulent IBDV.The rsults showed that protective responses and neutralization antibody responses of DNA vaccine co-administrated with chicken IL-2 were much higher than those of injected with DNA vaccine alone.Furthermore,the T lymphocyte proliferation response of peripheral blood, thymus and spleen,and the B lymphocyte proliferation response of bursa induced by DNA vaccine can be significantly enhanced by chicken IL-2.These results obviously indicated that chicken IL-2 was a strong adjuvant which can significantly enhance the immunogenicity of IBDV DNA vaccine.