Ma Hai-Ling, Shi Yu-Hong, Zhang Xue-Heng, Li Ming-Yun, Chen Jiong
Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo 315211, China.
Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo 315211, China; Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo 315211, China.
Fish Shellfish Immunol. 2016 Apr;51:70-76. doi: 10.1016/j.fsi.2016.02.013. Epub 2016 Feb 12.
Leukocyte cell-derived chemotaxin 2 (LECT2) is a multifunctional cytokine involved in many diseases in which immune dysfunction is present. Ayu LECT2 (PaLECT2), which interacts with a C-type lectin receptor (PaCLR), was shown to activate ayu head kidney-derived monocytes/macrophages (MO/MΦ) to improve the outcomes of fish upon bacterial infections. However, it is not known if PaCLR mediates PaLECT2 effects on ayu MO/MΦ. In this study, we determined the role of PaCLR in signal transduction of PaLECT2 on ayu MO/MΦ. We expressed the PaCLR ectodomain in Escherichia coli and produced a refolded recombinant protein (rPaCLR) that was then used to produce the anti-PaCLR IgG (anti-PaCLR) for neutralization. Addition of the refolded PaLECT2 mature peptide (rPaLECT2m) to ayu MO/MΦ cultures, increased cytokine expression, induced chemotaxis, and enhanced phagocytosis and bactericidal activity of these cells were observed. When we added anti-PaCLR to block the ectodomain of PaCLR, these effects were significantly inhibited. Based on our previous works and the data presented here, we conclude that PaCLR mediates the immunomodulatory effects of PaLECT2 on ayu MO/MΦ, thus defining a mechanism by which LECT2 protects fish against pathogens.
白细胞衍生趋化因子2（LECT2）是一种多功能细胞因子，参与存在免疫功能障碍的多种疾病。与C型凝集素受体（PaCLR）相互作用的香鱼LECT2（PaLECT2）已被证明可激活香鱼头肾来源的单核细胞/巨噬细胞（MO/MΦ），从而改善鱼类在细菌感染后的结局。然而，尚不清楚PaCLR是否介导PaLECT2对香鱼MO/MΦ的作用。在本研究中，我们确定了PaCLR在PaLECT2对香鱼MO/MΦ的信号转导中的作用。我们在大肠杆菌中表达了PaCLR胞外域，并产生了一种复性的重组蛋白（rPaCLR），然后用其制备用于中和的抗PaCLR IgG（抗PaCLR）。向香鱼MO/MΦ培养物中添加复性的PaLECT2成熟肽（rPaLECT2m），可观察到细胞因子表达增加、诱导趋化作用以及这些细胞的吞噬和杀菌活性增强。当我们添加抗PaCLR以阻断PaCLR的胞外域时，这些作用被显著抑制。基于我们之前的工作以及此处呈现的数据，我们得出结论，PaCLR介导PaLECT2对香鱼MO/MΦ的免疫调节作用，从而确定了LECT2保护鱼类抵御病原体的机制。
