Immunobiology for Aquaculture, Department of Cell Biology and Histology, Faculty of Biology, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, 30100 Murcia, Spain.
Oceanographic Centre of Murcia, Spanish Institute of Oceanography (IEO), Carretera de la Azohía s/n., Puerto de Mazarrón, 30860 Murcia, Spain.
Int J Mol Sci. 2020 Mar 31;21(7):2439. doi: 10.3390/ijms21072439.
Interleukin-17 (IL-17) cytokine comprises a family of six ligands in mammals with proinflammatory functions, having an important role in autoimmune disorders and against bacterial, viral, and fungal pathogens. While IL-17A and IL-17F ligands are mainly produced by Th cells (Th17 cells), the rest of the ligands are expressed by other immune and non-immune cells and have different functions. The identification of IL-17 ligands in fish has revealed the presence of six members, counterparts to mammalian ones, and a teleost-specific form, the fish IL-17N. However, tissue distribution, the regulation of gene expression, and scarce bioactivity assays point to similar functions compared to mammalian ones, though this yet to be investigated and confirmed. Thus, we have identified seven IL-17 ligands in the teleost European sea bass (), for the first time, corresponding to IL-17A/F1, IL-17A/F2, IL-17A/F3, IL-17C1, IL-17C2, IL-17D, and IL-17N, according to the predicted protein sequences and phylogenetic analysis. They are constitutively and widely transcribed in sea bass tissues, with some of them being mainly expressed in the thymus, brain or intestine. Upon stimulation of head-kidney leucocytes, the mRNA levels of all sea bass IL-17 ligands were up-regulated by phytohemagglutinin treatment, a well-known T cell mitogen, suggesting a major expression in T lymphocytes. By contrast, the infection of sea bass juveniles with nodavirus (NNV), a very pathogenic virus for this fish species, resulted in the up-regulation of the transcription of IL-17C1 in the head-kidney and of IL-17C1 and IL-17D in the brain, the target tissue for NNV replication. By contrast, NNV infection led to a down-regulated transcription of IL-17A/F1, IL-17A/F2, IL-17C1, IL-17C2, and IL-17D in the head-kidney and of IL-17A/F1 and IL-17A/F3 in the brain. The data are discussed accordingly with the IL-17 ligand expression and the immune response under the different situations tested.
白细胞介素-17（IL-17）细胞因子在哺乳动物中由六种配体组成，具有促炎功能，在自身免疫性疾病和对抗细菌、病毒和真菌病原体方面具有重要作用。虽然 IL-17A 和 IL-17F 配体主要由 Th 细胞（Th17 细胞）产生，但其余的配体由其他免疫和非免疫细胞表达，并具有不同的功能。鱼类中 IL-17 配体的鉴定揭示了六种成员的存在，与哺乳动物相对应，还有一种鱼类特有的形式，即鱼类 IL-17N。然而，组织分布、基因表达的调节以及缺乏生物活性测定表明，与哺乳动物相比，其功能相似，但这尚未得到研究和证实。因此，我们首次在硬骨鱼欧洲鲈鱼（）中鉴定出七种 IL-17 配体，分别对应于 IL-17A/F1、IL-17A/F2、IL-17A/F3、IL-17C1、IL-17C2、IL-17D 和 IL-17N，根据预测的蛋白质序列和系统发育分析。它们在鲈鱼组织中持续广泛转录，其中一些主要在胸腺、大脑或肠道中表达。在头部肾脏白细胞受到刺激后，所有欧洲鲈鱼 IL-17 配体的 mRNA 水平均被植物血球凝集素（一种已知的 T 细胞有丝分裂原）处理上调，这表明它们主要在 T 淋巴细胞中表达。相比之下，海水鲈鱼幼体感染神经坏死病毒（NNV）后，头部肾脏中 IL-17C1 的转录上调，大脑中 IL-17C1 和 IL-17D 的转录上调，NNV 是该鱼类的一种非常致病的病毒。相比之下，NNV 感染导致头部肾脏中 IL-17A/F1、IL-17A/F2、IL-17C1、IL-17C2 和 IL-17D 的转录下调，以及大脑中 IL-17A/F1 和 IL-17A/F3 的转录下调。根据不同情况下测试的 IL-17 配体表达和免疫反应，对数据进行了相应的讨论。
