Maeda Shingo, Ohno Koichi, Tsukamoto Atsushi, Nakashima Ko, Fukushima Kenjiro, 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):534-9. doi: 10.1016/j.vetimm.2011.12.004. Epub 2011 Dec 9.
The chemokine receptor CCR9, which interacts with the thymus-expressed chemokine TECK/CCL25, contributes to the localization of lymphocytes to the small intestine, and is implicated in the development of human inflammatory bowel disease (IBD); however, their role in canine IBD is unknown. The objective of this study was to isolate cDNA encoding CCR9 and to investigate CCR9 expression in normal canine tissues and lymphoid cell lines. The complete open reading frame contained 1104 bp, encoding 367 amino acids, with 85% and 81% identity to human and mouse homologs, respectively. CCR9 mRNA was detected in all tissues investigated with the highest expression level in the small intestine. CCR9 mRNA was also expressed in GL-1, a canine B cell leukemia cell line, but not in CLBL-1, a canine B cell lymphoma cell line. Immunoblot and flow cytometry analyses of these cell lines using an anti-human CCR9 monoclonal antibody revealed that CCR9 protein expression was detected only in GL-1, indicating the cross-reactivity of the antibody. Using the antibody, flow cytometry showed that the proportions of CCR9(+) cells were small (mean, 4.88%; SD, 2.15%) in the normal canine PBMCs. This study will be useful in understanding canine intestinal immunity and the immunopathogenesis of canine IBD.
趋化因子受体CCR9与胸腺表达的趋化因子TECK/CCL25相互作用，有助于淋巴细胞定位于小肠，并与人类炎症性肠病（IBD）的发生有关；然而，它们在犬类IBD中的作用尚不清楚。本研究的目的是分离编码CCR9的cDNA，并研究CCR9在正常犬组织和淋巴细胞系中的表达。完整的开放阅读框包含1104 bp，编码367个氨基酸，与人源和鼠源同源物的同一性分别为85%和81%。在所研究的所有组织中均检测到CCR9 mRNA，在小肠中的表达水平最高。CCR9 mRNA也在犬B细胞白血病细胞系GL-1中表达，但在犬B细胞淋巴瘤细胞系CLBL-1中不表达。使用抗人CCR9单克隆抗体对这些细胞系进行免疫印迹和流式细胞术分析显示，仅在GL-1中检测到CCR9蛋白表达，表明该抗体具有交叉反应性。使用该抗体，流式细胞术显示正常犬外周血单个核细胞（PBMC）中CCR9(+)细胞的比例较小（平均值为4.88%；标准差为2.15%）。本研究将有助于理解犬肠道免疫和犬IBD的免疫发病机制。
