Interleukin-2 (IL-2) in flounder (Paralichthys olivaceus): Molecular cloning, characterization and bioactivity analysis
Interleukin-2 (IL-2) in flounder (Paralichthys olivaceus): Molecular cloning, characterization and bioactivity analysis
复制标题
比目鱼（Paralichthys olivaceus）中的白细胞介素 2 (IL-2)：分子克隆、表征和生物活性分析
DOI：
10.1016/j.fsi.2019.07.023
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发表时间：
2019
影响因子：
4.7
通讯作者：
Zhan Wenbin
中科院分区：
文献类型：
--
作者：
Tang Xiaoqian;Guo Ming;Du Yang;Xing Jing;Sheng Xiuzhen;Zhan Wenbin
Interleukin-2 (IL-2) is mainly produced by CD4+T helper lymphocytes, which is an important immunomodulatory cytokine that primarily promotes activation, proliferation and differentiation of T cells. In the present study, flounder (Paralichthys olivaceus) interleukin 2 homologue (poIL-2) was identified for the first time, and its expression patterns were characterized in healthy, virus- or bacteria-infected flounder. The full-length cDNA sequences of poIL-2 was 989 bp with an open reading frame of 423 bp coding a polypeptide of 140 amino acids (aa). The deduced aa sequences shared low similarities (<53%) with other known fish IL-2s. Multiple alignment of aa sequences revealed that poIL-2 own the classical IL-2 family signature of “C-X(3)-EL-X(2)-(T/V)-(V/M/L)-(K/T/R)-X-EC” and “DS-X-(F/L)Y(A/T/S)P”. In healthy flounder, IL-2 mRNA was highly expressed in PBLs, spleen and hindgut, and moderately expressed in gill, trunk kidney and stomach. PHA, LPS and Con-A could effectively induce poIL-2 expression in primary cultured peripheral blood leukocytesin vitro. poIL-2 transcripts were significantly up-regulated in spleen, kidney, gill and hindgut post infections withEdwardsiella tardaand Hirame novirhabdovirus (HIRRV). The eukaryotic expression vector encoding poIL-2 (pcIL-2) was constructed and intramuscularly injected, which could be successfully expressed in flounders and induced significantly higher expressions of six immune related genes including poIL-2,β-defensin, CD4-1, CD8α, IFN-γ and TNF-α compared with the injection with control plasmid. Moreover, pretreatment with pcIL-2 could markedly increase the survival rate of flounder challenged with HIRRV. Our results demonstrated that poIL-2 plays an important role in the induction of immune responses and immune defense against bacterial and virus infection, which indicated its potential use as an immunopotentiator to prevent diseases in flounder.
