Djordjevic Brankica, Skugor Stanko, Jørgensen Sven Martin, Overland Margareth, Mydland Liv Torunn, Krasnov Aleksei
Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, PO Box 5003, As NO-1432, Norway.
Fish Shellfish Immunol. 2009 Feb;26(2):201-9. doi: 10.1016/j.fsi.2008.10.012. Epub 2008 Nov 5.
Immunostimulants (IS) are considered a promising approach for improving resistance to pathogens in fish aquaculture. At present, development of IS are complicated due to limited knowledge on the mechanisms of their action. To assess the use of global gene expression analysis for screening of candidate IS we applied lentinan, a beta-glucan from the mushroom Lentinula edodes, as a model. After feeding rainbow trout (Oncorhynchus mykiss) with lentinan-supplemented (L) and control (C) diets for 37 days, fish were injected with bacterial lipopolysaccharide (LPS), a classical inducer of inflammation. Gene expression was analyzed in LPS-challenged compared to saline-injected fish using a salmonid 1.8k cDNA microarray (SFA2.0 immunochip) and real-time qPCR. Spleen was selected for data analyses due to highest magnitude of responses and its key role in the fish immune system. A group of genes implicated in acute inflammatory responses was higher induced in C versus L, including IFN-related and TNF-dependent genes (galectins and receptors, signal transducers and transcription factors), genes involved in MHC class I antigen presentation and leukocyte recruitment. A similar trend was observed in metabolism of iron and xenobiotics, markers of oxidative and cellular stress. Interestingly, differences between C and L were similar to those observed between salmon with low and high resistance to infectious salmon anemia virus. Genes with equal responses to LPS in L and C were related to cell communication (cytokines, chemokines and receptors), signal transduction, activation of immune cells, apoptosis, cellular maintenance and energy metabolism. In conclusion, lentinan decreased the expression of genes involved in acute inflammatory reactions to the inflammatory agent while major parts of the immune response remained unchanged. Such effects are expected for IS, which should modify immunity by enhancing beneficial and reducing detrimental responses.
免疫刺激剂（IS）被认为是提高鱼类养殖中病原体抵抗力的一种有前景的方法。目前，由于对其作用机制的了解有限，免疫刺激剂的开发较为复杂。为了评估利用全局基因表达分析来筛选候选免疫刺激剂，我们应用香菇多糖（一种来自香菇的β-葡聚糖）作为模型。在用添加香菇多糖的（L）和对照（C）饲料喂养虹鳟（Oncorhynchus mykiss）37天后，给鱼注射细菌脂多糖（LPS），这是一种经典的炎症诱导剂。与注射生理盐水的鱼相比，在LPS刺激的鱼中使用鲑科1.8k cDNA微阵列（SFA2.0免疫芯片）和实时定量PCR分析基因表达。由于反应程度最高且其在鱼类免疫系统中的关键作用，选择脾脏进行数据分析。与L组相比，C组中一组与急性炎症反应相关的基因诱导程度更高，包括与干扰素相关和肿瘤坏死因子依赖性基因（半乳糖凝集素和受体、信号转导子和转录因子）、参与MHC I类抗原呈递和白细胞募集的基因。在铁和异生素代谢、氧化和细胞应激标志物方面也观察到类似趋势。有趣的是，C组和L组之间的差异与对传染性鲑鱼贫血病毒抵抗力低和高的鲑鱼之间观察到的差异相似。在L组和C组中对LPS反应相同的基因与细胞通讯（细胞因子、趋化因子和受体）、信号转导、免疫细胞激活、细胞凋亡、细胞维持和能量代谢有关。总之，香菇多糖降低了对炎症剂急性炎症反应相关基因的表达，而免疫反应的主要部分保持不变。免疫刺激剂预期会有这样的效果，即通过增强有益反应和减少有害反应来调节免疫力。
