PaCLR介导PaLECT2激活脂多糖刺激的香鱼(Plecoglossus altivelis)单核巨噬细胞功能

PACLR MEDIATES THE EFFECT OF PALECT2 ON LPS-STIMULATED MONOCYTES/MACROPHAGES FROM AYU PLECOGLOSSUS ALTIVELIS

香鱼(Plecoglossus altivelis)白细胞衍生趋化因子2(leukocyte cell-derived chemotaxin 2,PaLECT2)可以激活香鱼头肾来源的单核巨噬细胞(monocytes/macrophages,MO/MΦ),提高细菌感染后香鱼存活率。进一步研究显示,PaLECT2与香鱼C型凝集素受体(C-type lectin receptor,PaCLR)相互作用可激活静息状态下香鱼MO/MΦ,增强其免疫活性。在前期基础上,本研究通过抗体封闭实验检测PaCLR是否介导PaLECT2激活LPS刺激的MO/MΦ功能。结果显示,重组PaLECT2成熟肽(rPaLECT2m)显著提高了LPS刺激的香鱼MO/MΦ细胞因子的表达,并增强了其吞噬能力和杀菌活性。封闭PaCLR显著抑制了rPaLECT2m激活LPS刺激的香鱼MO/MΦ细胞因子表达、吞噬和杀菌功能。因此,PaCLR介导PaLECT2可以激活病理状态香鱼MO/MΦ。这一认识进一步揭示了LECT2在病理状态的鱼类巨噬细胞调控和炎症反应中的作用及机制。

Leukocyte cell-derived chemotaxin 2 of ayu Plecoglossus altivelis（Pa LECT2） is shown to activate ayu head kidney-derived monocytes/macrophages（MO/MΦ） in vitro to improve the cure of bacterial-infected fish. Our earlier research reveals that Pa LECT2 could activate the resting MO/MΦ and enhance its immuno-activity by interacting with a C-type lectin receptor of ayu（Pa CLR）, based on which we examined the effect of Pa CLR on Pa LECT2 activation of LPS-stimulated ayu MO/MΦ using antibody neutralization method. Results show that the recombinant Pa LECT2 mature peptide（r Pa LECT2m） increased the cytokine expression, and enhanced phagocytosis and bactericidal activity of LPS-stimulated ayu MO/MΦ. By blocking the ectodomain of Pa CLR by anti-Pa CLR, these effects were inhibited significantly. Therefore, Pa CLR could mediate the activation effect of Pa LECT2 on LPS stimulated MO/MΦ. This finding revealed the mechanism of LECT2 involvement in the regulation and inflammatory response of the fish monocyte/macrophage.