College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, People's Republic of China.
College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, People's Republic of China; State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, People's Republic of China.
Poult Sci. 2023 Oct;102(10):102957. doi: 10.1016/j.psj.2023.102957. Epub 2023 Jul 25.
The H9N2 subtype of avian influenza virus (H9N2 AIV) has caused significant losses in chicken flocks throughout China. At present, consensus has been reached that field isolates of H9N2 underwent antigenic drift to evolve into distinct groups with significant antigenic divergence from the commercially available vaccines in China. This project continues to monitor the evolution characteristics of H9N2 hemagglutinin (HA) genes in China over the past 3 yr. The results showed that the current circling H9N2 viruses were diversified into h9.4.2.5 subclade, which was genetically distant from commonly used commercial vaccine strains. Compared with vaccine strains or 2014 strains, more than 42.1% of the variable antigenic sites in recent 3 yr' strains have shown significant changes and these stacked changes have caused significant differences in antigenicity. We constructed a recombinant vaccine strain rCQY-GHHA, which uses A/Chicken/China/SichuanCQY/2014 as the framework and A/Chicken/China/SichuanGH/2020 strain, which meets the recent viral antigenic characteristics, as the HA gene donor. The recombinant strain was prepared as an oil-adjuvant inactivated vaccine following an industrial process. The results of the immune protection experiment showed that the rCQY-GHHA vaccine was better than the commercial vaccine strain SS in reducing the morbidity, pathological lesion, virus shedding, and viral load. These results provide a reference for the control of H9N2 AIV in China.
在中国，禽流感病毒 H9N2 亚型（H9N2 AIV）已导致鸡群遭受重大损失。目前，人们普遍认为，H9N2 野毒株发生抗原漂移，进化成与中国市售疫苗具有显著抗原差异的不同群体。本项目持续监测过去 3 年中国 H9N2 血凝素（HA）基因的进化特征。结果表明，当前循环的 H9N2 病毒已分化为 h9.4.2.5 亚分支，与常用的商业疫苗株在遗传上相距甚远。与疫苗株或 2014 年分离株相比，近 3 年分离株中有超过 42.1%的可变抗原位点发生了显著变化，这些叠加变化导致抗原性差异显著。我们构建了一种重组疫苗株 rCQY-GHHA，该疫苗以 A/鸡/中国/四川 CQY/2014 株作为骨架，以 A/鸡/中国/四川 GH/2020 株作为 HA 基因供体，该供体株符合当前病毒的抗原特征。采用工业生产工艺，将重组株制备为油佐剂灭活疫苗。免疫保护实验结果表明，rCQY-GHHA 疫苗在降低发病率、病理损伤、病毒脱落和病毒载量方面优于商品化疫苗株 SS。这些结果为中国 H9N2 AIV 的防控提供了参考。
