Uchida Yuko, Takemae Nobuhiro, Saito Takehiko
Influenza and Prion Disease Research Center, National Institute of Animal Health, National Agriculture and Food Research Organization (NARO), Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
J Vet Med Sci. 2014 Aug;76(8):1111-7. doi: 10.1292/jvms.13-0620. Epub 2014 May 8.
In this study, reverse genetics was applied to produce vaccine candidate strains against highly pathogenic avian influenza viruses (HPAIVs) of the H5N1 subtype. The H5 subtype vaccine strains were generated by a reverse genetics method in a biosafety level 2 facility. The strain contained the HA gene from the H5N1 subtype HPAIV attenuated by genetic modification at the cleavage site, the NA gene derived from the H5N1 subtype HPAI or the H5N3 subtype of avian influenza virus and internal genes from A/Puerto Rico/8/34. Vaccination with an inactivated recombinant virus with oil-emulsion completely protected chickens from a homologous viral challenge with a 640 HAU or 3,200 HAU/vaccination dose. Vaccination with a higher dose of antigen, 3,200 HAU, was effective at increasing survival and efficiently reduced viral shedding even when challenged by a virus of a different HA clade. The feasibility of differentiation of infected from vaccinated animals (DIVA) was demonstrated against a challenge with H5N1 HPAIVs when the recombinant H5N3 subtype viruses were used as the antigens of the vaccine. Our study demonstrated that the use of reverse genetics would be an option to promptly produce an inactivated vaccine with better matching of antigenicity to a circulating strain.
在本研究中，应用反向遗传学方法制备针对H5N1亚型高致病性禽流感病毒（HPAIV）的候选疫苗毒株。H5亚型疫苗毒株通过反向遗传学方法在生物安全2级设施中构建。该毒株包含经裂解位点基因改造减毒的H5N1亚型HPAIV的血凝素（HA）基因、源自H5N1亚型HPAI或H5N3亚型禽流感病毒的神经氨酸酶（NA）基因以及来自A/波多黎各/8/34的内部基因。用含油佐剂的灭活重组病毒疫苗接种，能使鸡完全抵御640血凝素单位（HAU）或3200 HAU/剂量的同源病毒攻击。接种更高剂量抗原（3200 HAU）可有效提高存活率，并能在鸡受到不同HA分支病毒攻击时有效减少病毒排泄。当使用重组H5N3亚型病毒作为疫苗抗原时，证明了该疫苗具有区分感染动物和免疫动物（DIVA） 的可行性。我们的研究表明，使用反向遗传学方法可以迅速制备出抗原性与流行毒株更匹配的灭活疫苗。
