Expression and functional characterization of collection-K1 from Nile tilapia (Oreochromis niloticus) in host innate immune defense. (November 2018)

• Record Type: Journal Article
• Authors: Mu, Liangliang; Yin, Xiaoxue; Bian, Xia; Wu, Liting; Yang, Yanjian; Wei, Xiufang; Guo, Zheng; Ye, Jianmin
• Is Part Of: Molecular immunology. Volume 103(2018:Nov.)
• Page Start: 21
• Page End: 34
• Publication Date: 2018-11
• Subjects: Oreochromis niloticus -- CL-K1 -- Agglutination -- Opsonization -- Streptococcus agalactiae -- Aeromonas hydrophila; Immunochemistry -- Periodicals; Molecular biology -- Periodicals; Immunochemistry -- Periodicals; Allergy and Immunology -- Periodicals; Molecular Biology -- Periodicals; Immunochimie -- Périodiques; Biologie moléculaire -- Périodiques; Immunochemistry; Molecular biology; Periodicals; Electronic journals; 571.96
• DOI: 10.1016/j.molimm.2018.08.012
• Languages: English
• ISSNs: 0161-5890

Abstract

Highlights: The CL-K1 gene was identified in Nile tilapia ( OnCL-K1 ). OnCL-K1 expression was significantly up-regulated following challenges with Streptococcus galactiae and Aeromonas hydrophila . Recombinant OnCL-K1 possessed agglutination and opsonization ability to both bacteria ( Streptococcus galactiae and Aeromonas hydrophila ). Recombinant OnCL-K1 was able to participate in the regulation of inflammatory and migration reaction. Abstract: Collectin-K1 (CL-K1), a multifunctional Ca 2+ -dependent lectin, is able to bind carbohydrates on pathogens and inhibit infection by direct neutralization, agglutination, opsonization and killing, which plays an important role in innate immunity. In this study, a CL-K1 homolog (OnCL-K1) was identified from Nile tilapia ( Oreochromis niloticus ) and characterized at expression and agglutination functional levels. The open reading frame of OnCL-K1 is 720 bp of nucleotide sequence encoding a polypeptide of 239 amino acids. The deduced amino acid sequence has two characteristic structures, containing a collagen-like region and a carbohydrate recognition domain. Expression analysis revealed that the OnCL-K1 was highly expressed in the liver, and widely exhibited in other tissues including kidney, intestine and spleen. In addition, the OnCL-K1 expression was significantly up-regulated in spleen and anterior kidney following challenges with a Gram-positive bacterial pathogen ( Streptococcus agalactiae ) and a Gram-negative bacterial pathogen ( Aeromonas hydrophila ). The up-regulation of OnCL-K1 expression was also demonstrated in hepatocytes and monocytes/macrophages in vitro stimulation with S. agalactiae and A. hydrophila . Recombinant OnCL-K1 protein was able to agglutinate both S. agalactiae and A. hydrophila in vitro, and participate in the regulation of inflammatory, migration reaction and promote the phagocytosis by monocytes/macrophages. Taken together, the results of this study indicated that OnCL-K1, possessing apparent agglutination, opsonization and killing ability to bacterial pathogens and participating in the regulation mechanisms of the non-specific cellular immune, might be involved in host defense of innate immunity against bacterial infection in Nile tilapia.