不同类型H5亚型禽流感疫苗的免疫保护效力比较研究

Comparison of Protective Efficacy among Different Types of H5 Subtype Avian Influenza Vaccines

为比较以我国首个H5亚型禽流感病毒分离株A/Goose/Guangdong/1/1996(H5N1)[GS/GD/96]为基础构建的新型重组禽流感病毒灭活疫苗(H5N1亚型,Re-1株)、禽流感重组鸡痘病毒载体活疫苗(H5亚型)、禽流感、新城疫重组二联活疫苗(rLH5-1株)以及禽流感DNA疫苗(H5亚型,pH5-GD)的免疫保护效力。分别将四种禽流感疫苗以2.8μg HA/0.3 mL(肌肉注射)、103PFU/100μL(刺种)、106EID50/100μL(滴鼻、点眼)、15μg/200μL(肌肉注射)等不同剂量和方式免疫3周龄SPF鸡,首次免疫3周后再加强免疫一次,加强免疫2周后用106EID50的高致病力禽流感病毒(HPAIV)GS/GD/96鼻腔途径进行攻击,观察发病与死亡情况。分别于攻毒后第3 d、第5 d、第7 d采集喉头及泄殖腔拭子进行病毒分离、滴定检测排毒情况,同时检测免疫及攻毒后血清HI抗体的动态变化。所有疫苗均可对免疫鸡形成100%完全保护(不发病、不致死、不排毒);在病毒攻击前,灭活疫苗(H5N1亚型,Re-1株)、禽流感重组鸡痘病毒载体活疫苗(H5亚型)、禽流感、新城疫重组二联活疫苗(rLH5-1株)以及禽流感DNA疫苗(H5亚型,pH5-GD)所诱导的HI抗体平均水平分别为8.75log2、6.5log2、5.13log2和7.88log2。新型的基因工程疫苗具有良好的免疫保护性,已经或将在H5亚型HPAIV的防治实践中起到有益的补充作用。

To evaluate the protective efficacies of four different types of avian influenza vaccines, including the reassortant avian influenza virus vaccine, inactived （H5N1 subtype, strain Re-1 ）, recombinant fowlpox virus vector- based live vaccine（ H5 subtype）, avian influenza and newcastle disease recombinant vaccine, live（ Strain rLH5-1 ） and avian influenza DNA vaccine（ H5 Subtype, pH5-GD）, which were all constructed on the bases of the first H5N1 isolate A/Goose/Guangdong/1/1996 （ H5N1 ） [ GS/GD/961. Groups of 3-week-old specific pathogen free （SPF） chickens were intramuscularly injected （2.8 μg HA/0. 3 mL）, via wing-web puncture （103 PFU/100μL）, oculonasal administration （10^6EID50/100μL） and intramuscularly injected （15 μg/200 μL） with four differenttypes of H5 avian influenza vaccines, respectively. Boosts were conducted with the same dosage after three weeks. All chickens were nasally challenged with 10^6EID50 of highly pathogenic avian influenza virus （HPAIV） GS/GD/96 at two weeks after the boost. Oropharyngeal and cloacal swabs were collected from all groups at 3 d, 5 d and 7 d post the challenge for titration of virus in embryo eggs, and the chickens were observed daily for disease signs and deaths for 2 weeks. Meanwhile, sera were collected weekly after vaccination and challenge to detect the dynamics of the hemagglutinin inhibition （HI） antibodies. Complete protections, indicated by no disease signs, no death, and no virus shedding, were monitored in all vaccinated groups. The average HI titers induced by the four vaccines were 8. 751og2, 6.51og2, 5.131og2 and 7.881og2 before challenge, respectively. Our results indicated that all the vaccines were able to induce highly protective efficacies in SPF chickens and have potentials of H5NI vaccine candidates in pratice.