The Biological Functions and Intestinal Inflammation Regulation of IL-21 in Grass Carp (<i>Ctenopharyngodon idella</i>) during Infection with <i>Aeromonas hydrophila</i>
Gaoliang Yuan,
Weihua Zhao,
Yanwei Zhang,
Zhao Jia,
Kangyong Chen,
Junya Wang,
Hao Feng,
Jun Zou
Affiliations
Gaoliang Yuan
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China
Weihua Zhao
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China
Yanwei Zhang
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China
Zhao Jia
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China
Kangyong Chen
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China
Junya Wang
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China
Hao Feng
State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha 410081, China
Jun Zou
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China
Interleukin (IL) 21 is a pleiotropic cytokine that plays an important role in regulating innate and adaptive immune responses. In fish, the biological functions and cell source of IL-21 remain largely unknown. In this study, we performed qRT-PCR, Western blotting and immunofluorescent microscopy to examine the expression of IL-21 at the mRNA and protein levels. We found that il21 expression was induced in the primary head kidney leukocytes of grass carp (Ctenopharyngodon idella) by heat-inactivated Aeromonas hydrophila (A. hydrophila) and LPS and in tissues after infection with A. hydrophila. Recombinant IL-21 protein produced in the CHO-S cells was effective in elevating the expression of antibacterial genes, including β-defensin and lysozyme, and, interestingly, inhibited the NF-κB signaling pathway. Furthermore, we investigated the response of the IL-21 expressing cells to A. hydrophila infection. Immunofluorescent assay showed that IL-21 protein was detected in the CD3γ/δ T cells and was markedly accumulated in the anterior, middle and posterior intestine. Collectively, the results indicate that IL-21 plays an important role in regulating the intestinal inflammation induced by bacterial infection in grass carp.
