Castro Rosario, Abós Beatriz, Pignatelli Jaime, von Gersdorff Jørgensen Louise, González Granja Aitor, Buchmann Kurt, Tafalla Carolina
Centro de Investigación en Sanidad Animal (CISA-INIA), Valdeolmos (Madrid), Spain.
Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.
PLoS One. 2014 Oct 22;9(10):e111084. doi: 10.1371/journal.pone.0111084. eCollection 2014.
Among the essential metabolic functions of the liver, in mammals, a role as mediator of systemic and local innate immunity has also been reported. Although the presence of an important leukocyte population in mammalian liver is well documented, the characterization of leukocyte populations in the teleost liver has been only scarcely addressed. In the current work, we have confirmed the presence of IgM+, IgD+, IgT+, CD8α+, CD3+ cells, and cells expressing major histocompatibility complex (MHC-II) in rainbow trout (Oncorhynchus mykiss) liver by flow cytometry and/or immunohistochemistry analysis. Additionally, the effect of viral hemorrhagic septicemia virus (VHSV) on the liver immune response was assessed. First, we studied the effect of viral intraperitoneal injection on the transcription of a wide selection of immune genes at days 1, 2 and 5 post-infection. These included a group of leukocyte markers genes, pattern recognition receptors (PRRs), chemokines, chemokine receptor genes, and other genes involved in the early immune response and in acute phase reaction. Our results indicate that T lymphocytes play a key role in the initial response to VHSV in the liver, since CD3, CD8, CD4, perforin, Mx and interferon (IFN) transcription levels were up-regulated in response to VHSV. Consequently, flow cytometry analysis of CD8α+ cells in liver and spleen at day 5 post-infection revealed a decrease in the number of CD8α+ cells in the spleen and an increased population in the liver. No differences were found however in the percentages of B lymphocyte (IgM+ or IgD+) populations. In addition, a strong up-regulation in the transcription levels of several PRRs and chemokines was observed from the second day of infection, indicating an important role of these factors in the response of the liver to viral infections.
在哺乳动物中，肝脏的基本代谢功能还包括作为全身和局部先天免疫的介质。虽然哺乳动物肝脏中存在重要白细胞群体已得到充分证明，但硬骨鱼肝脏中白细胞群体的特征却很少有人研究。在当前这项研究中，我们通过流式细胞术和/或免疫组织化学分析，证实了虹鳟（Oncorhynchus mykiss）肝脏中存在IgM+、IgD+、IgT+、CD8α+、CD3+细胞以及表达主要组织相容性复合体（MHC-II）的细胞。此外，还评估了病毒性出血性败血症病毒（VHSV）对肝脏免疫反应的影响。首先，我们研究了病毒腹腔注射在感染后第1天、第2天和第5天对多种免疫基因转录的影响。这些基因包括一组白细胞标志物基因、模式识别受体（PRR）、趋化因子、趋化因子受体基因以及其他参与早期免疫反应和急性期反应的基因。我们的结果表明，T淋巴细胞在肝脏对VHSV的初始反应中起关键作用，因为CD3、CD8、CD4、穿孔素、Mx和干扰素（IFN）的转录水平因VHSV而上调。因此，感染后第5天对肝脏和脾脏中CD8α+细胞的流式细胞术分析显示，脾脏中CD8α+细胞数量减少，而肝脏中的细胞群体增加。然而，B淋巴细胞（IgM+或IgD+）群体的百分比没有差异。此外还观察到，从感染第二天起，几种PRR和趋化因子的转录水平大幅上调，表明这些因素在肝脏对病毒感染的反应中起重要作用。
