禽流感重组禽痘病毒rFPV-HA-NA活载体疫苗的研究

目的：确定重组禽痘病毒rFPV-HA-NA疫苗株的最佳免疫剂量、免疫日龄、免疫产生时间及免疫持续期。方法：用重组禽痘病毒rFPV-HA-NA疫苗免疫SPF鸡，免疫后用HPAIVH5N1和H7N1AIV进行致死性攻击，观察疫苗免疫后的保护效果。结果：大约含100个PFU的重组病毒即能使机体获得对强毒攻击的100％保护；对1日龄SPF鸡进行免疫接种，4周后能100％抵抗HPAIV的致死性攻击；2周和3周龄的免疫鸡对免疫周1后的强毒攻击具有100％的保护力；重组病毒在免疫后10个月时，其诱导产生的血凝抑制（Haemagglutinin inhibition，HI）抗体仍保持在2-3log2水平，并可以提供100％抵抗病毒的致死性感染。结论：重组禽痘病毒rFPV-HA-NA疫苗是一种安全、高效的基因工程疫苗，它有望在不久的将来替代全病毒灭活疫苗用于高致病力禽流感的预防。

Studies on live fowlpox virus vector-based vaccine of avian influenza rFPV-HA-NA

ObjectiveIn this study, the immune duration, selection o f the optimal dose and timing of administration of recombinant fowlpox virus rFP V HA NA was evaluated in SPF chickens.MethodsThe SPF chicken s immunized with rFPV HA NA were challenged with H5N1 or H7N1 isolate of HPAI virus. The chickens were observed daily for two weeks for clinical signs of infe ction and the protection ratio were calculated.Results Recombin ant virus containing 100 plaque form units (PFU) could induce complete protectio n against challenge with HPAIV. One day old SPF chickens vaccinated with rFPV HA NA could survive the lethal infection of HPAIV. Immune efficacy, with 100% protection rate, was obtained one week after the immunization with this kind of vaccine, and could last for ten months after immunization accompanied by haemag glutinin inhibition antibody of 2-3 log2 titers. Conclusion Th e recombinant fowlpox vaccine is a safe and highly efficient gene engineering va ccine candidate, and it will replace the current inactivated vaccines for preven ting HPAI in near future.