Department of Veterinary Preventive Medicine, College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, Jilin 130062, China.
College of Agriculture and Forestry Science, Linyi University, Shuangling Road, Linyi City, 276005, Shandong Province, China.
Vet Microbiol. 2019 Jan;228:173-180. doi: 10.1016/j.vetmic.2018.11.006. Epub 2018 Nov 16.
Newcastle disease virus (NDV) and H9 subtype avian influenza virus (AIV) are two avian pathogens across the globe. Inasmuch as most poultry flocks worldwide are vaccinated with a live low-virulence or attenuated NDV vaccine, we embarked on the development of vaccine prototypes that would have dual specificities and would allow a single immunization against both avian influenza (AI) and Newcastle disease (ND). Therefore, in the present work, a cloned full-length copy of the genome of the lentogenic NDV strain rmNA-1 was selected as a backbone vector to construct three chimeric NDVs that expressed (i) the ORF encoding the HA, (ii) the ectodomain of HA fused with the transmembrane domain and cytoplasmic tail regions derived from the NDV F protein and (iii) the ectodomain of HA fused with a short GS linker and the GCN4 sequences, and designated as rmNA-H9, rmNA-H9F, and rmNA-H9 (ECTO), respectively. rmNA-H9, rmNA-H9F, and rmNA-H9 (ECTO) stably expressed the modified HA gene for 10 egg passages and the three recombinants were found innocuous to chickens. The insertion of the chimeric HA-F, rather than HA-ECTO or ORF of HA, resulted in a recombinant virus with enhanced incorporation of the HA protein into the viral surface. A single immunization of SPF chickens with the three recombinants induced NDV- and AIV H9-specific antibodies, and protected chickens against a challenge with a lethal dose of velogenic NDV or AIV H9N2. Remarkably, non-shedding of influenza virus and higher levels of H9 subtype HI titers were observed 7 days post challenge (dpc) in rmNA-H9F vaccinated chickens, than other recombinants. Furthermore, a prime-boost vaccination of chickens with rmNA-H9F induced higher levels of NDV- and H9- HI and secretory IgA, as well as reduced viral shedding and virus-induced gross lesions, compared with the commercial vaccine. Therefore, the recombinant rmNA-H9F is a promising bivalent vaccine candidate against NDV and H9 subtype AIV in chickens.
新城疫病毒（NDV）和 H9 亚型禽流感病毒（AIV）是两种全球范围内的禽类病原体。由于世界上大多数家禽群体都接种了低毒力或减毒的 NDV 活疫苗，因此我们开始开发具有双重特异性的疫苗原型，以便能够对禽流感（AI）和新城疫（ND）进行单次免疫。因此，在本工作中，选择了一株具有低致病性的 NDV 毒株 rmNA-1 的全长克隆基因组作为骨架载体，构建了三种表达（i）HA 编码 ORF、（ii）HA 的胞外域与 NDV F 蛋白的跨膜域和胞质尾区融合、（iii）HA 的胞外域与短 GS 接头和 GCN4 序列融合的嵌合 NDV。分别命名为 rmNA-H9、rmNA-H9F 和 rmNA-H9（ECTO）。rmNA-H9、rmNA-H9F 和 rmNA-H9（ECTO）在 10 个鸡蛋传代中稳定表达了修饰的 HA 基因，并且三种重组体对鸡均无毒。嵌合 HA-F 的插入，而不是 HA-ECTO 或 HA 的 ORF，导致重组病毒中 HA 蛋白更有效地掺入病毒表面。SPF 鸡单次免疫三种重组体可诱导 NDV 和 AIV H9 特异性抗体，并可预防致死剂量的强毒 NDV 或 AIV H9N2 的攻毒。值得注意的是，与其他重组体相比，rmNA-H9F 免疫接种的鸡在攻毒后 7 天（dpc）未检测到流感病毒的脱落，且 H9 亚型 HI 滴度更高。此外，rmNA-H9F 的鸡初免-加强免疫可诱导更高水平的 NDV 和 H9-HI 以及分泌型 IgA，并且与商业疫苗相比，降低了病毒脱落和病毒诱导的大体病变。因此，重组 rmNA-H9F 是一种有前途的针对鸡的 NDV 和 H9 亚型 AIV 的二价疫苗候选物。
