The H9N2 avian influenza viruses cause significant economic losses in poultry worldwide and could potentially cause human pandemic. Currently, the available vaccines have limited efficacy due to antigenic drift of H9N2. To improve vaccine efficacy, we developed monovalent vaccine strain via the modification of neutralizing epitopes on hemagglutinin (HA) to broaden the protection against H9N2 viruses. In this study, single and multiple mutation were introduced to amino acid at position 148, 150 (site I) and 183, 186, 188 (site II) on the full-length HA gene of H9N2 strain (A/Hong Kong/33982/2009). These mutant HA constructs were displayed on the baculovirus surface (BacH9), and evaluated for their cross-protective efficacy against H9N2 viruses in a mouse model. Our findings indicate that mice immunized with multiple BacH9 mutant constructs (148-150 183 and 186) induced cross-protective immunity against circulating H9N2 in the viral challenge study and prove to be a promising vaccine candidate for H9N2.

中文翻译：

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修饰血凝素中和表位以开发具有广泛保护作用的H9N2疫苗。

H9N2禽流感病毒在全球范围内给家禽造成重大经济损失，并有可能引起人类大流行。当前，由于H9N2的抗原漂移，可获得的疫苗具有有限的功效。为了提高疫苗效力，我们通过修饰血凝素（HA）的中和表位来开发单价疫苗株，以扩大对H9N2病毒的保护。在这项研究中，在H9N2毒株全长HA基因（A / Hong Kong / 33982 /）的第148、150（I位）和183、186、188（II位）位置的氨基酸处引入了单突变和多突变。 2009）。将这些突变的HA构建体展示在杆状病毒表面（BacH9）上，并在小鼠模型中评估其对H9N2病毒的交叉保护功效。