Liu Yuzhuo, Zhao Dongmin, Zhang Jingfeng, Huang Xinmei, Han Kaikai, Liu Qingtao, Yang Jing, Zhang Lijiao, Li Yin
Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
GuoTai (Taizhou) Center of Technology Innovation for Veterinary Biologicals, Taizhou 225300, China.
Vaccines (Basel). 2023 Mar 5;11(3):596. doi: 10.3390/vaccines11030596.
Avian influenza virus (AIV) subtype H9N2 is the most widespread AIV in poultry worldwide, causing great economic losses in the global poultry industry. Chickens and ducks are the major hosts and play essential roles in the transmission and evolution of H9N2 AIV. Vaccines are considered an effective strategy for fighting H9N2 infection. However, due to the differences in immune responses to infection, vaccines against H9N2 AIV suitable for use in both chickens and ducks have not been well studied. This study developed an inactivated H9N2 vaccine based on a duck-origin H9N2 AIV and assessed its effectiveness in the laboratory. The results showed that the inactivated H9N2 vaccine elicited significant haemagglutination inhibition (HI) antibodies in both chickens and ducks. Virus challenge experiments revealed that immunization with this vaccine significantly blocked virus shedding after infection by both homogenous and heterologous H9N2 viruses. The vaccine was efficacious in chicken and duck flocks under normal field conditions. We also found that egg-yolk antibodies were produced by laying birds immunized with the inactivated vaccine, and high levels of maternal antibodies were detected in the serum of the offspring. Taken together, our study showed that this inactivated H9N2 vaccine could be extremely favourable for the prevention of H9N2 in both chickens and ducks.
H9N2亚型禽流感病毒（AIV）是全球家禽中分布最广的禽流感病毒，给全球家禽业造成了巨大经济损失。鸡和鸭是主要宿主，在H9N2禽流感病毒的传播和进化中起着重要作用。疫苗被认为是对抗H9N2感染的有效策略。然而，由于对感染的免疫反应存在差异，适用于鸡和鸭的抗H9N2禽流感病毒疫苗尚未得到充分研究。本研究基于一株鸭源H9N2禽流感病毒研制了一种灭活H9N2疫苗，并在实验室评估了其有效性。结果表明，该灭活H9N2疫苗在鸡和鸭体内均能诱导产生显著的血凝抑制（HI）抗体。病毒攻毒实验表明，用该疫苗免疫可显著阻断同源和异源H9N2病毒感染后的病毒排出。该疫苗在正常田间条件下对鸡群和鸭群均有效。我们还发现，用灭活疫苗免疫的产蛋鸡能产生蛋黄抗体，并且在其后代血清中检测到高水平的母源抗体。综上所述，我们的研究表明，这种灭活H9N2疫苗对预防鸡和鸭的H9N2感染可能极为有利。
