鸡IL-18对禽多杀性巴氏杆菌DNA疫苗的免疫佐剂作用

为了探索鸡IL-18在禽多杀性巴氏杆菌H基因DNA疫苗中的免疫佐剂作用,分别用共表达鸡IL-18基因和禽多杀性巴氏杆菌C48-1H基因的DNA疫苗、鸡IL-18真核表达质粒pcDNA3/cIL-18与禽多杀性巴氏杆菌C48-1H基因的DNA疫苗混合物、禽多杀性巴氏杆菌C48-1H基因的DNA疫苗肌肉注射5周龄鸡,首免后每周采取外周血及外周抗凝血,应用ELISA和MTT法分别检测免疫鸡的体液免疫及细胞免疫水平。二免后第2周用10 LD50禽多杀性巴氏杆菌强毒菌株C48-1进行攻击。结果鸡IL-18能够明显增强禽多杀性巴氏杆菌H基因DNA疫苗的免疫原性,显著提高免疫鸡的体液免疫和细胞免疫水平,并且鸡IL-18与禽多杀性巴氏杆菌H基因共表达时的免疫佐剂作用最强,能强有力地抵抗强毒菌株C48-1的致死性攻击。结果表明,鸡IL-18可作为DNA疫苗的一种理想的免疫佐剂。

Adjuvant effect of chicken IL-18 on the immune responses to DNA vaccine against avian Pasteurella multocida

Five-week-old chickens were inoculated intramuscularly with pcDNA3/cIL-18,pcDNA3/cIL-18 and pcDNA3/ompH,co-expressing plasmid pcDNA3/ompH-cIL-18 or pcDNA3/ompH respectively to elucidate the adjuvant effect of chicken IL-18 on the DNA vaccines expressing the outer membrane protein of avian Pasteurella multocida C48-1.After first immunization,peripheral blood lymphocytes were detected by MTT and the sera were collected to examine antibodies of chickens each week by ELISA.The chickens were challenged with 10 LD50 avian P.multocida C48-1 on week 2 post the booster.The results showed that chicken IL-18 was able to improve obviously the immunogenicity of the DNA vaccine,and to enhance the humoral immunity level and cellular immunity level of the vaccinated chickens.The adjuvant effect of IL-18 was the strongest when it was co-expressed with H gene in eukaryotic expression vector pcDNA3.Therefore,chickens vaccinated with recombinant DNA vaccine pcDNA3/ompH-cIL8 were protected effectively against challenge with avian P.multocida C48-1.