Song Baifen, Li Xiaoting, Ma Jinzhu, Yu Liquan, Feng Zhenyue, Liu Zhenhua, Cui Yudong
College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China.
Cytogenet Genome Res. 2017;153(1):36-45. doi: 10.1159/000481522. Epub 2017 Nov 24.
Interferon-γ (IFN-γ), a cytokine produced by activated natural killer cells and T lymphocytes, is an important regulator of innate and adaptive immunity. Interleukin (IL)-18, also known as IFN-γ-inducing factor, is a cytokine that induces T and natural killer cells to produce IFN-γ. In this study, the chicken IL-18 (ChIL-18) and chicken IFN-γ (ChIFN-γ) genes were inserted into the pET28a prokaryotic expression vector, resulting in pET28a-IL-18 and pET28a-IFN-γ, respectively. These plasmids were transformed into Escherichia coli strain BL21, and the ChIL-18 and ChIFN-γ proteins were expressed and purified. To determine their antiviral activities, 200 ng/mL of ChIL-18 and/or ChIFN-γ were inoculated into chicken embryonic fibroblast cells. After 24 h, one 50% tissue culture infective dose (TCID50) of infectious bursal disease virus (IBDV) was inoculated into the chicken embryonic fibroblast cells. The results showed that the antiviral effect of ChIL-18 and ChIFN-γ in combination was better than that of ChIL-18 or ChIFN-γ alone. Next, 14-day-old chicken were injected with 200 µg of ChIL-18 and/or ChIFN-γ and then were challenged with 103 TCID50 of IBDV via intraperitoneal injection. The results showed that the proliferation of IBDV was inhibited by the injection of the recombinant proteins, especially the combination of ChIL-18 and ChIFN-γ, as evidenced by cytokine detection, quantitative PCR, and pathology analyses. These results indicate that ChIL-18 and ChIFN-γ could inhibit IBDV infection and the combination of ChIL-18 and ChIFN-γ has a better inhibitory effect than either cytokine alone.
干扰素-γ（IFN-γ）是一种由活化的自然杀伤细胞和T淋巴细胞产生的细胞因子，是先天性和适应性免疫的重要调节因子。白细胞介素（IL）-18，也称为IFN-γ诱导因子，是一种诱导T细胞和自然杀伤细胞产生IFN-γ的细胞因子。在本研究中，将鸡IL-18（ChIL-18）和鸡IFN-γ（ChIFN-γ）基因插入pET28a原核表达载体，分别得到pET28a-IL-18和pET28a-IFN-γ。将这些质粒转化到大肠杆菌BL21菌株中，表达并纯化ChIL-18和ChIFN-γ蛋白。为了确定它们的抗病毒活性，将200 ng/mL的ChIL-18和/或ChIFN-γ接种到鸡胚成纤维细胞中。24小时后，将一个50%组织培养感染剂量（TCID50）的传染性法氏囊病病毒（IBDV）接种到鸡胚成纤维细胞中。结果表明，ChIL-18和ChIFN-γ联合使用的抗病毒效果优于单独使用ChIL-18或ChIFN-γ。接下来，给14日龄的鸡注射200 μg的ChIL-18和/或ChIFN-γ，然后通过腹腔注射用103 TCID50的IBDV进行攻毒。结果表明，注射重组蛋白可抑制IBDV的增殖，尤其是ChIL-18和ChIFN-γ的组合，细胞因子检测、定量PCR和病理学分析均证明了这一点。这些结果表明，ChIL-18和ChIFN-γ可抑制IBDV感染，且ChIL-18和ChIFN-γ的组合比单独使用任何一种细胞因子具有更好的抑制效果。
