To evaluate the optimal administration frequency for interferon-α (IFN-α) and the effect of its combined use with inactive virus on chicken flocks, the prokaryotic expression plasmid pET-22b-ChIFN-α was constructed and transferred into Escherichia coli BL21(DE3) host bacteria to induce the expression of chicken IFN-α and to harvest recombinant proteins inclusion bodies. The expression of recombinant chicken IFN-α was confirmed by SDS-PAGE, and the results demonstrated that the chicken IFN-α (20 kDa) was highly expressed using the prokaryotic expression vector with a concentration of 0.2 mg/mL in the medium. Chicken IFN-α was diluted to 2.5×10⁴ U/fowls and administered to immunized specific-pathogen-free chickens orally in combination with inactivated H9N2 subtype influenza virus. Chicken that received chicken IFN-α were safe after three repeated immunizations (96 h). In addition, chicken IFN-α could induce higher levels of antiviral-related inducible genes in peripheral blood, spleen, and thymus of chicken flocks. The results of a challenge assay revealed that the lowest detoxification rates of chicken IFN-α ranged from three to five days, suggesting a higher capacity to resist H9N2 subtype avian influenza virus. The present study obtained the optimal immune frequency and immunization period for chicken IFN-α to provide theoretical support for the optimal clinical application of IFN-α.
为研究口服鸡α 干扰素最佳的给药频率及与灭活病毒联合使用对鸡群的影响，文中将构建的原核表达质粒pET-22b-ChIFN-α 转入大肠杆菌Escherichia coli BL21 (DE3)，宿主菌经诱导表达收获重组包涵体蛋白，经变性、纯化、复性后获得重组鸡α 干扰素。SDS-PAGE 结果分析显示，目的蛋白可在原核表达载体中高效表达，发酵液上清中目的蛋白浓度高达0.2 mg/mL，分子量约为20 kDa。将鸡α 干扰素稀释至活性为2.5×10⁴ U/羽份，与灭活H9N2 亚型流感病毒联用以口服的方式免疫无特定病原 (SPF) 鸡群，试验结果表明，短期 (96 h) 重复免疫3 次，鸡α 干扰素具有较好的安全性，可诱导鸡群的外周血、脾脏及胸腺产生较高水平的抗病毒相关的诱导基因，攻毒结果显示鸡α 干扰素使用次数为连续使用3–5 d 鸡群排毒率最低，体现出较好的抗流感病毒能力。本研究结果获得了鸡α 干扰素的最佳免疫频率及免疫时间，为干扰素的最佳临床应用方法提供理论支撑。.
Keywords: H9N2 influenza viruses; chicken interferon α; oral administration; short-term repeated.