Molecular and Functional Characterization of α Chain of Interleukin-15 Receptor (<i>IL-15Rα</i>) in Orange-Spotted Grouper (<i>Epinephelus coioides</i>) in Response to <i>Vibrio harveyi</i> Challenge
Yilin Zhang,
Fan Wu,
Guanjian Yang,
Jichang Jian,
Yishan Lu,
Zhiwen Wang
Affiliations
Yilin Zhang
Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen Institute of Guangdong Ocean University, Shenzhen 518120, China
Fan Wu
Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen Institute of Guangdong Ocean University, Shenzhen 518120, China
Guanjian Yang
Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen Institute of Guangdong Ocean University, Shenzhen 518120, China
Jichang Jian
Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China
Yishan Lu
Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen Institute of Guangdong Ocean University, Shenzhen 518120, China
Zhiwen Wang
Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen Institute of Guangdong Ocean University, Shenzhen 518120, China
Interleukin-15 (IL15) is a proinflammatory cytokine that could induce the production of inflammatory cytokines. In this study, the α chain of the IL15 receptor of Epinephelus coioides (Ec-IL15Rα), a natural regulator of IL15, was identified, and immune response functions of fish were determined and characterized. Ec-IL15Rα contains a 720 bp open reading frame that encodes 239 amino acids, including four typical conserved cysteine residues with a highly conserved sushi domain. Ec-IL15Rα is closely related to Epinephelus lanceolatus and is the most clustered with teleost. Subcellular localization studies showed that Ec-IL15Rα was situated in the cytoplasm and cell membrane. Ec-IL15Rα was detected in 11 tissues, with the highest expression in the liver and blood. Meanwhile, the Ec-IL15Rα transcriptional levels substantially increased in nine tissues after Vibrio harveyi infection. Ec-IL15Rα was significantly up-regulated in HKLs by ConA, PHA, LPS and poly I:C stimulation. In vitro analysis, the recombinant protein of rEc-IL15Rα stimulates HKL proliferation and IL1R, IL6R, IL10, and IL16 expression. Challenge experiments revealed that IL15Rα protein showed an increase of 6.67–10% survival protection rate after V. harveyi infection. This study provides a better understanding of the immune protection of IL15Rα in vertebrate fish.
