title: Identification of a C-type lectin with antiviral and antibacterial activity from pacific white shrimp Litopenaeus vannamei.
abstract: C-type lectins (CTLs) play crucial roles in innate immune responses in invertebrates by recognizing and eliminating microinvaders. In this study, a CTL from pacific white shrimp Litopenaeus vannamei (LvCTL3) was identified. LvCTL3 contains a single C-type lectin-like domain (CTLD), which shows similarities to those of other shrimp CTLs and has a mutated 'EPD' motif in Ca(2+)-binding site 2. LvCTL3 mRNA can be detected in all tested tissues and expression of LvCTL3 in gills was up-regulated after Lipopolysaccharides, poly (I:C), Vibrio parahaemolyticus and white spot syndrome virus (WSSV) challenges, suggesting activation responses of LvCTL3 to bacterial, virus and immune stimulant challenges. The 5'flanking regulatory region of LvCTL3 was cloned and we identified a NF-κB binding motif in the LvCTL3 promoter region. Dual-luciferase reporter assays indicated that over-expression of L. vannamei dorsal can dramatically up regulate the promoter activity of LvCTL3, suggesting that LvCTL3 expression could be regulated through NF-κB signaling pathway. As far as we know, this is the first report on signaling pathway involve in shrimp CTLs expression. The recombinant LvCTL3 protein was expressed in Escherichia coli and purified by Ni-affinity chromatography. The purified LvCTL3 can agglutinate Gram-negative microbe Vibrio alginolyticus and V. parahaemolyticus and Gram-positive bacteria Bacillus subtilis in the presence of calcium ions, but cannot agglutinate Gram-positive bacteria Streptococcus agalactiae. The agglutination activity of LvCTL3 was abolished when Ca(2+) was chelated with EDTA, suggesting the function of LvCTL3 is Ca(2+)-dependent. In vivo challenge experiments showed that the recombinant LvCTL3 protein can significantly reduce the mortalities of V. parahemolyticus and WSSV infection, indicating LvCTL3 might play significant roles in shrimp innate immunity defense against bacterial and viral infection.
authors.affiliation: MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China; Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Institute of Fisheries, Nanning, PR China.
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.affiliation: MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China.
authors.forename: Chaozheng
authors.initials: C
authors.lastname: Li
authors.affiliation: Guangxi Veterinary Research Institute, Guangxi University, Nanning, PR China.
authors.forename: Chunxia
authors.initials: C
authors.lastname: Ma
authors.affiliation: MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China.
authors.forename: Haoyang
authors.initials: H
authors.lastname: Li
authors.affiliation: MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China.
authors.forename: Hongliang
authors.initials: H
authors.lastname: Zuo
authors.affiliation: MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China.
authors.forename: Shaoping
authors.initials: S
authors.lastname: Weng
authors.affiliation: Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Institute of Fisheries, Nanning, PR China.
authors.forename: Xiaohan
authors.initials: X
authors.lastname: Chen
authors.affiliation: Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Institute of Fisheries, Nanning, PR China.
authors.forename: Digang
authors.initials: D
authors.lastname: Zeng
authors.affiliation: MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China; School of Marine Sciences, Sun Yat-sen University, Guangzhou, PR China. Electronic address: lsshjg@mail.sysu.edu.cn.
authors.forename: Jianguo
authors.initials: J
authors.lastname: He
authors.affiliation: MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China. Electronic address: xuxpeng@mail.sysu.edu.cn.
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Xu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000998:Antiviral Agents / Q000494:pharmacology*; D060829:Arthropod Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000494:pharmacology; D001483:Base Sequence; D002478:Cells, Cultured; D017124:Conserved Sequence; D006434:Hemocytes / Q000276:immunology / Q000378:metabolism; D054884:Host-Pathogen Interactions; D007113:Immunity, Innate; D037181:Lectins, C-Type / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000502:physiology; D009928:Organ Specificity; D033561:Penaeidae / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D015854:Up-Regulation / Q000276:immunology; D014736:Vibrio parahaemolyticus / Q000187:drug effects / Q000276:immunology; D046848:White spot syndrome virus 1 / Q000187:drug effects / Q000276:immunology
chemical_list: D000900:Anti-Bacterial Agents; D000998:Antiviral Agents; D060829:Arthropod Proteins; D037181:Lectins, C-Type; D016328:NF-kappa B
keywords: Agglutination; C-type lectin; Innate immunity; Litopenaeus vannamei; NF-κB signaling pathway; WSSV