H5亚型禽流感DNA疫苗pCAGGoptiHA5对鸭免疫保护效力的研究

Protective efficacy of DNA vaccine pCAGGoptiHA5 of H5 subtype avian influenza virus in ducks

为评价H5亚型禽流感病毒(AIV)DNA疫苗pCAGGoptiHA5对鸭的免疫保护效力,本研究将pCAGGoptiHA5以20μg、30μg和50μg剂量免疫3周龄SPF鸭,首次免疫后3周加强免疫一次。2周后以105EID50的鸭源高致病力AIV由鼻腔攻毒,观察SPF鸭发病和死亡情况。分别于攻毒后3d、5d和7d采集喉头及泄殖腔拭子进行病毒分离,检测鸭排毒情况及免疫和攻毒后血凝抑制(HI)抗体、中和(NT)抗体的动态变化。结果表明:30μg和50μg免疫组均可对免疫鸭产生100%保护,而20μg剂量组则可对免疫鸭提供80%保护。

To evaluate the protection of DNA vaccine pCAGGoptiHA5 encoding HA gene of H5 subtype avian influenza virus（AIV） in ducks,groups of 3-week-old SPF ducks were intramuscularly injected with 20 μg,30 μg and 50 μg of DNA vaccine,respectively,boosted with the same dosage after three weeks.All ducks were nasally challenged with 105 EID50 of highly pathogenic H5N1 subtype AIV at two weeks after the boost.Oropharyngeal and cloacal swabs were collected from ducks in all groups at 3,5 and 7 days post the challenge for virus isolation in chicken embryos,and the sera were collected after vaccination and challenge to measure the titers of antibodies by hemagglutinin inhibition and neutralization test.Results shown that a complete protection was achieved in groups with a dose as low as 30 μg of the DNA vaccine,without any clinic signs,death,or virus shedding.However,only 80% protection was provided in 20 μg of dosage groups.