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ORIGINAL RESEARCH article

Front. Immunol.

Sec. Comparative Immunology

Volume 16 - 2025 | doi: 10.3389/fimmu.2025.1654890

This article is part of the Research TopicDeciphering Fish Immune Responses: Cellular Roles and Pathogen RecognitionView all 5 articles

Identification of Galectin 9(CcGal-9) and its antibacterial function in Yellow River carp (Cyprinus carpio haematopterus)

Provisionally accepted
Li  WangLi Wang1,2,3Yuanyuan  HuYuanyuan Hu1Xudong  LiXudong Li4Ziyan  ZhangZiyan Zhang1Nan  WangNan Wang1Limin  ChaoLimin Chao1Chengfei  LiChengfei Li1Pei  GaoPei Gao5Jinyou  MaJinyou Ma1,2*Lei  WangLei Wang6*Xiaojing  XiaXiaojing Xia1,7*
  • 1Henan Institute of Science and Technology, Xinxiang, China
  • 2Postdoctoral Research Base, Henan Institute of Science and Technology, Xinxiang, China
  • 3Postdoctoral Research Station in Biological Sciences, Henan Normal University, Xinxiang, China
  • 4Fishery Technology Extension Station of Henan Provincex, Zhengzhou, China
  • 5Henan Fisheries Technology Extension Center, Zhengzhou, China
  • 6College of Life Science, Henan Normal University, Xinxiang, China
  • 7Ministry of Education Key Laboratory for Animal Pathogens and Biosafety, Zhengzhou, China

The final, formatted version of the article will be published soon.

Galectin-9 is a β-galactoside-binding lectin that functions as a critical pattern recognition receptor (PRR) in the host immune system. It initiates immune defense responses by recognizing and binding to pathogen-associated molecular patterns (PAMPs) located on the surface of microorganisms. In this study, a novel galectin-9 cDNA, designated CcGal-9, was identified in Yellow River carp (Cyprinus carpio haematopterus). The full-length cDNA of CcGal-9 is 963 base pairs (bp) in length and encodes a protein comprising 320 amino acids (aa). The predicted CcGal-9 protein contains two distinct carbohydrate recognition domains (CRDs), characteristic of tandem-repeat type galectins. CcGal-9 mRNA was predominantly expressed in the spleen, testicle and head kidney, with relatively lower expression levels detected in the liver and intestine. Upon infection with Aeromonas hydrophila and Staphylococcus aureus, CcGal-9 expression was significantly upregulate in the liver, spleen, head kidney, kidney, gill and intestine. Recombinant CcGal-9 (rCcGal-9), purified from Escherichia coli BL21 (DE3), exhibited binding activity for lipopolysaccharides (LPS), peptidoglycans (PGN), mannan and various microorganisms, including both Gram-negative and Gram-positive bacteria. Moreover, rCcGal-9 demonstrated the ability to bind and agglutinate a broad spectrum of microorganisms. Furthermore, supplementation with varying concentrations of rCcGal-9 significantly improved the survival rate of Cyprinus carpio following infection with A. hydrophila. In summary, this study suggests that CcGal-9 plays a critical role in the immune defense of C. carpio against pathogenic microorganisms by functioning as an important PRR that recognizes PAMPs and agglutinates invading microbes.

Keywords: galectin-9, Cyprinus carpio haematopterus, innate immunity, Agglutinating activity, Binding ability

Received: 27 Jun 2025; Accepted: 04 Aug 2025.

Copyright: © 2025 Wang, Hu, Li, Zhang, Wang, Chao, Li, Gao, Ma, Wang and Xia. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Jinyou Ma, Henan Institute of Science and Technology, Xinxiang, China
Lei Wang, College of Life Science, Henan Normal University, Xinxiang, China
Xiaojing Xia, Henan Institute of Science and Technology, Xinxiang, China

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