Live Attenuated Influenza Viruses Containing NS1 Truncations as Vaccine Candidates against H5N1 Highly Pathogenic Avian Influenza
Live Attenuated Influenza Viruses Containing NS1 Truncations as Vaccine Candidates against H5N1 Highly Pathogenic Avian Influenza
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DOI：
10.1128/jvi.01920-08
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发表时间：
2009-02-15
影响因子：
5.4
通讯作者：
Palese, Peter
中科院分区：
文献类型：
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作者：
Steel, John;Lowen, Anice C.;Palese, Peter
由于与最近在家禽中广泛传播的H5 N1流感病毒株相关的高死亡率、H5 N1病毒从鸟类到人类的反复引入以及通过消除受影响的鸡群来根除H5 N1的困难，非常需要针对HPAI（高致病性禽流感）的有效疫苗。利用反向遗传学，产生了一组基于重组H5 N1流感病毒A/Viet Nam/1203/04的实验性减毒活疫苗株。每种病毒通过表达其中多碱基切割位点已被去除的血凝素蛋白来减毒。产生具有全长NS 1或73、99或126个氨基酸的C-末端截短的NS 1蛋白的病毒。将具有每种NS基因型的病毒与在位置627处携带赖氨酸或谷氨酸的PB 2聚合酶基因组合。我们预测PB 2的627位的谷氨酸将使病毒在哺乳动物宿主中减毒，从而增加疫苗的安全性。所有重组病毒在10日龄鸡胚中均生长至高滴度，但在哺乳动物细胞培养物中均减毒。通过干扰素生物测定证明了所有在NS 1蛋白中具有截短的病毒诱导高水平的β干扰素。在小鼠模型中发现病毒均高度减毒。用表达H5 N1血凝素和神经氨酸酶蛋白的小鼠致死病毒攻击时，用单剂量的任何病毒接种疫苗都能提供完全的保护，使其免于死亡。在鸡模型中，用单剂量的编码NS 11 -99蛋白的所选病毒进行疫苗接种完全保护鸡免受同源HPAI病毒A/Viet Nam/1203/04（H5 N1）的致死性攻击，并提供了高水平的保护免受异源病毒A/egret/Egypt/01/06（H5 N1）的攻击。因此，通过在血凝素、NS 1和PB 2编码区引入突变而减毒的重组甲型流感/Viet Nam/1203/04病毒显示出减毒活疫苗所需的特征，并具有在家禽以及哺乳动物宿主中作为候选疫苗的潜力。
Due to the high mortality associated with recent, widely circulating strains of H5N1 influenza virus in poultry, the recurring introduction of H5N1 viruses from birds to humans, and the difficulties in H5N1 eradication by elimination of affected flocks, an effective vaccine against HPAI (highly pathogenic avian influenza) is highly desirable. Using reverse genetics, a set of experimental live attenuated vaccine strains based on recombinant H5N1 influenza virus A/Viet Nam/1203/04 was generated. Each virus was attenuated through expression of a hemagglutinin protein in which the polybasic cleavage site had been removed. Viruses were generated which possessed a full-length NS1 or a C-terminally truncated NS1 protein of 73, 99, or 126 amino acids. Viruses with each NS genotype were combined with a PB2 polymerase gene which carried either a lysine or a glutamic acid at position 627. We predicted that glutamic acid at position 627 of PB2 would attenuate the virus in mammalian hosts, thus increasing the safety of the vaccine. All recombinant viruses grew to high titers in 10-day-old embryonated chicken eggs but were attenuated in mammalian cell culture. Induction of high levels of beta interferon by all viruses possessing truncations in the NS1 protein was demonstrated by interferon bioassay. The viruses were each found to be highly attenuated in a mouse model. Vaccination with a single dose of any virus conferred complete protection from death upon challenge with a mouse lethal virus expressing H5N1 hemagglutinin and neuraminidase proteins. In a chicken model, vaccination with a single dose of a selected virus encoding the NS1 1-99 protein completely protected chickens from lethal challenge with homologous HPAI virus A/Viet Nam/1203/04 (H5N1) and provided a high level of protection from a heterologous virus, A/egret/Egypt/01/06 (H5N1). Thus, recombinant influenza A/Viet Nam/1203/04 viruses attenuated through the introduction of mutations in the hemagglutinin, NS1, and PB2 coding regions display characteristics desirable for live attenuated vaccines and hold potential as vaccine candidates in poultry as well as in mammalian hosts.