A single CRD C-type lectin from Eriocheir sinensis (EsLecB) with microbial-binding, antibacterial prophenoloxidase activation and hem-encapsulation activities. (March 2016)

• Record Type: Journal Article
• Authors: Fang, Zi-Yan; Li, Dan; Li, Xue-Jie; Zhang, Xing; Zhu, You-Ting; Li, Wei-Wei; Wang, Qun
• Is Part Of: Fish & shellfish immunology. Volume 50(2016:May)
• Page Start: 175
• Page End: 190
• Publication Date: 2016-03
• Subjects: C-type lectin -- Pattern recognition receptor -- Eriocheir sinensis -- Antibacterial activity; Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2016.01.031
• Languages: English
• ISSNs: 1050-4648

Abstract

Abstract: C-type lectins (CTLs) exist widely in crustaceans. To date, thirteen CTLs have been reported in crustaceans, and play significant roles in pathogen recognition, encapsulation of hemocytes and antimicrobial activity in the innate immune response. Based on the initial expressed sequence tags (EST) of a hepatopancreatic cDNA library, a novel CTL, designated as EsLecB, with a 470 bp open reading frame encodes a polypeptide of 156 amino acids, including a signal peptide of 19 amino acid residues and one carbohydrate-recognition domain of 131 aa residues, was cloned from the crustacean Eriocheir sinensis . By qRT-PCR analysis, EsLecB was detected in all tested tissues, and showed highest expression in hemocytes, hepatopancreas and heart. The expression of EsLecB was up-regulated following injections of PAMPs or bacteria. The recombinant protein (rEsLecB) expressed in Escherichia coli had a calcium-independent but carbohydrate-dependent microbial-binding and microbial-agglutinating, microorganism growth inhibitory and hem-encapsulation activities. Moreover, the rEsLecB could stimulate the activation of prophenoloxidase in vitro. These results indicated that EsLecB, as an antibacterial pattern recognition receptor is involved in innate immunity, and may act as an upstream detector of the prophenoloxidase activating system, which can detect pathogen invasion in E. sinensis . Highlights: A novel C-type lectin Es LecB is up-regulated following injections of PAMPs or bacteria in Eriocheir sinensis hemocytes. r Es LecB could binds to wide range of microorganisms in a Ca 2+ -dependent manner. r Es LecB could suppress microbial growth exhibited a bactericidal activity. r Es lecB could activate the phenoloxidase activity in E.sinensis hemocytes lysate supernatant. r Es LecB could stimulate the cellular encapsulation in vitro.