Yang Man, Zhou Ling, Wang Hai-Qing, Luo Xiao-Chun, Dan Xue-Ming, Li Yan-Wei
College of Marine Sciences, South China Agricultural University, 483 Wushan Street, Tianhe District, Guangzhou 510642, Guangdong Province, PR China.
School of Bioscience and Biotechnology, South China University of Technology, Guangzhou 510006, PR China.
Fish Shellfish Immunol. 2017 Aug;67:402-410. doi: 10.1016/j.fsi.2017.06.039. Epub 2017 Jun 15.
Among other functions, CCL25/CCR9 has an important role in regulating the trafficking of developing T cells in the thymus, and in homing memory T cells to the small intestine. The function of this chemokine-receptor complex is not well studied in fish. We identified a CCL25-like (EcCCL25, 108 aa) and two CCR9-like sequences (EcCCR9aa 373 aa; and EcCCR9b, 375 aa) from a transcriptome database of orange-spotted grouper (Epinephelus coioides). EcCCL25, EcCCR9a, and EcCCR9b shared conserved structural features with homologs from mammals and from other fish, and a consistent relationship with phylogenetic trees and sequence identities. In healthy grouper, EcCCL25, EcCCR9a, and EcCCR9b were highly expressed in the thymus, and the gills, were expressed at lower levels in the stomach, and had different expression levels in other tissues. After infection with Cryptocaryon irritans, EcCCL25 expression was up-regulated at early time points in the spleen and head kidney, and in the skin, and gills at later time points; EcCCR9a expression was increased in the gill, spleen, and head kidney. After infection with C. irritans, EcCCR9b expression was reduced in all tissues tested. These results suggested that grouper CCL25/CCR9a complex may be involved in host defense against C. irritans infection.
在其他功能中，CCL25/CCR9在调节发育中的T细胞在胸腺中的运输以及记忆T细胞归巢至小肠方面发挥着重要作用。这种趋化因子 - 受体复合物在鱼类中的功能尚未得到充分研究。我们从红斑石斑鱼（Epinephelus coioides）的转录组数据库中鉴定出一个CCL25样序列（EcCCL25，108个氨基酸）和两个CCR9样序列（EcCCR9a，373个氨基酸；以及EcCCR9b，375个氨基酸）。EcCCL25、EcCCR9a和EcCCR9b与哺乳动物和其他鱼类的同源物具有保守的结构特征，并且与系统发育树和序列同一性具有一致的关系。在健康的石斑鱼中，EcCCL25、EcCCR9a和EcCCR9b在胸腺中高度表达，在鳃中表达水平较低，在胃中表达水平不同，在其他组织中的表达水平也不同。感染刺激隐核虫后，EcCCL25在脾脏和头肾的早期时间点以及皮肤和鳃的后期时间点表达上调；EcCCR9a在鳃、脾脏和头肾中的表达增加。感染刺激隐核虫后，EcCCR9b在所有测试组织中的表达均降低。这些结果表明，石斑鱼CCL25/CCR9a复合物可能参与宿主对刺激隐核虫感染的防御。
