Maeda Shingo, Ohno Koichi, Nakashima Ko, Fukushima Kenjiro, Tsukamoto Atsushi, Suzuki Hiyoshi, Fujiwara Aki, Goto-Koshino Yuko, Fujino Yasuhito, Tsujimoto Hajime
Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Tokyo 113-8657, Japan.
Vet Immunol Immunopathol. 2012 Jan 15;145(1-2):100-9. doi: 10.1016/j.vetimm.2011.10.018. Epub 2011 Nov 17.
Fractalkine, also known as CX(3)CL1, is a unique chemokine that mediates inflammatory responses and is involved in the pathogenesis of several inflammatory disorders, including inflammatory bowel disease (IBD) in humans. In this study, we isolated cDNAs encoding canine fractalkine and its receptor CX(3)CR1, and assessed the biological activity of these molecules. The deduced amino acid sequence of the canine fractalkine cDNA showed 66% and 57% identity to human and mouse homologs, respectively. The N-terminal chemokine domain of the canine fractalkine showed 68% and 65% identity to human and mouse counterparts, respectively. The canine CX(3)CR1 amino acid sequence showed close homology to its human (83% identity) and mouse (81% identity) counterparts. Fractalkine and CX(3)CR1 mRNA were detected in all tissues in this study. Relatively higher expression levels of fractalkine mRNA were observed in the brain, medulla spinalis, small intestine, and mesenteric lymph nodes (MLNs), whereas higher expression levels of CX(3)CR1 mRNA were observed in the medulla spinalis, brain, liver, small intestine, and MLNs. The cross-reactivities of anti-human fractalkine antibody and anti-rat CX(3)CR1 antibody to canine proteins were confirmed using recombinant canine fractalkine and a cell line overexpressing canine CX(3)CR1, respectively. A transwell chemotaxis assay showed that the recombinant canine fractalkine induced migration in canine lymphoid cells expressing CX(3)CR1. The present study will be useful in understanding the canine immune system and the immunopathogenesis of canine inflammatory diseases.
趋化因子，也称为CX(3)CL1，是一种独特的趋化因子，可介导炎症反应，并参与多种炎症性疾病的发病机制，包括人类的炎症性肠病（IBD）。在本研究中，我们分离出编码犬趋化因子及其受体CX(3)CR1的cDNA，并评估了这些分子的生物学活性。犬趋化因子cDNA推导的氨基酸序列与人类和小鼠同源物分别具有66%和57%的同一性。犬趋化因子的N端趋化因子结构域与人类和小鼠对应结构域分别具有68%和65%的同一性。犬CX(3)CR1氨基酸序列与其人类（83%同一性）和小鼠（81%同一性）对应序列显示出密切的同源性。在本研究的所有组织中均检测到趋化因子和CX(3)CR1 mRNA。在脑、脊髓、小肠和肠系膜淋巴结（MLN）中观察到趋化因子mRNA相对较高的表达水平，而在脊髓、脑、肝、小肠和MLN中观察到CX(3)CR1 mRNA较高的表达水平。分别使用重组犬趋化因子和过表达犬CX(3)CR1的细胞系证实了抗人趋化因子抗体和抗大鼠CX(3)CR1抗体与犬蛋白的交叉反应性。Transwell趋化试验表明，重组犬趋化因子可诱导表达CX(3)CR1的犬淋巴细胞迁移。本研究将有助于理解犬免疫系统以及犬炎症性疾病的免疫发病机制。
