Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan.
Fish Shellfish Immunol. 2009 Dec;27(6):763-7. doi: 10.1016/j.fsi.2009.08.004. Epub 2009 Aug 21.
Interleukin-8 (IL-8) is a CXC-type chemokine with a chemotactic activity mainly on neutrophils and plays a key role in promoting inflammation. In teleosts, several CXC-chemokines have been cloned and characterized as being IL-8-like. Phylogenetic data however indicate that the reported teleost IL-8-like chemokines are substantially remote from mammalian IL-8, forming a fish-specific clade of IL-8-like chemokines distinct from that of tetrapod IL-8. In the present study, a novel IL-8-like chemokine, designated CaIL-8, has been found in the expressed sequence tags of carp gills and identified as an orthologue of mammalian IL-8. The CaIL-8 transcript encodes 99 amino acids containing a typical CXC motif but lacks an ELR motif, as in most teleost IL-8-like chemokines. Phylogenetic tree constructed by the maximum likelihood method suggests a closer relationship of CaIL-8 with mammalian IL-8 than with other teleost CXC-chemokines reported to be IL-8-like. In a normal unstimulated carp, CaIL-8 mRNA was detected by RT-PCR only in gills, kidney, spleen, heart and peripheral blood leukocytes, in contrast to a previously reported carp IL-8-like chemokine CXCa, which shows ubiquitous basal expression. The results, taken together, are strongly indicative of the presence of two major IL-8-like lineages of CXC-chemokines in teleost.
白细胞介素-8（IL-8）是一种 CXC 型趋化因子，具有主要针对中性粒细胞的趋化活性，在促进炎症中起着关键作用。在硬骨鱼中，已经克隆并鉴定了几种 CXC-趋化因子，它们类似于 IL-8。然而，系统发育数据表明，报道的硬骨鱼 IL-8 样趋化因子与哺乳动物的 IL-8 有很大的不同，形成了一个与四足动物 IL-8 不同的鱼类特异性 IL-8 样趋化因子分支。在本研究中，在鲤鱼鳃的表达序列标签中发现了一种新的 IL-8 样趋化因子，命名为 CaIL-8，并鉴定为哺乳动物 IL-8 的同源物。CaIL-8 转录本编码 99 个氨基酸，含有典型的 CXC 基序，但缺乏 ELR 基序，如大多数硬骨鱼 IL-8 样趋化因子。最大似然法构建的系统发育树表明，CaIL-8 与哺乳动物 IL-8 的关系比与其他报道的类似于 IL-8 的硬骨鱼 CXC-趋化因子更为密切。在正常未刺激的鲤鱼中，通过 RT-PCR 仅在鳃、肾脏、脾脏、心脏和外周血白细胞中检测到 CaIL-8 mRNA，而之前报道的鲤鱼 IL-8 样趋化因子 CXCa 则表现出普遍的基础表达。这些结果强烈表明，在硬骨鱼中存在两种主要的 IL-8 样 CXC 趋化因子谱系。
