表达H5亚型禽流感病毒HA基因的DNA疫苗免疫保护效力研究

Protection Efficacity of DNA Vaccine Encoding Hemagglutinin of H5 Subtype Avian Influenza Virus

表达高致病力禽流感病毒分离株A/Goose/Guangdong/1/96(H5N1) [GD/1/96(H5N1)]HA基因的DNA疫苗质粒pCIHA5具有良好的免疫保护性,为了将其开发并应用于实际,对其免疫保护效力进行了进一步的研究。结果表明,用10、40、70、100和150g pCIHA5和油苗1次免疫后,其免疫保护率分别为12.5%(1/8)、58.3%(7/12)、72.7%(8/11)、50.0%(6/12)、66.7%(8/12)和100%(12/12),其中70和100g剂量组的病毒分离结果为1/8和2/6;用剂量为5、20、35和50g pCIHA5分别免疫2次,免疫保护率分别为45.5%(5/11)、58.3%(7/12)、58.3%(7/12)和91.7%(11/12),5g的病毒分离结果为1/5,其余组未分离出病毒;pCIHA5免疫后AGP抗体均未检出,油苗免疫后其HI抗体虽高,但AGP抗体也呈阳性。结果显示,加强免疫应为DNA疫苗质粒pCIHA5的安全免疫方式,DNA疫苗质粒pCIHA5虽具有较为稳定的免疫原性和免疫保护性,但有必要进一步提高其在肌肉组织中的有效表达水平和抗体反应水平。

The DNA vaccine pCIHA5 encoding hemagglutinin can protect SPF chicken against lethal H5N1 avianinfluenza virus challenge. The more characters about its protection efficacity were studied. The protective rates in 10,40, 70,100 and 150g groups which immunized pCIHA5 were 12.5% (1/8), 58.3% (7/12), 72.7% (8/11), 50.0% (6/12) and 66.7% (8/12),respectively. The protective rates in 5, 20, 35 and 50g groups were 45.5% ( 5/11), 58.3% (7/12), 58.3% (7/12) and 91.7% (11/12),respectively. The 70, 100 and 5g groups have virus shedding with 1/8、2/6 and 1/5. Though the inactived oil-emulsion vaccine has high HI antibody titers and 100% protective rate, the AGP antibody could be detected after vaccination.Results show that the pCIHA5 is fit to boost by intramuscular injection. This would be useful to the study on geneengineering vaccine of avian influenza virus.