Endogenous molecules induced by a pathogen-associated molecular pattern (PAMP) elicit innate immunity in shrimp

• Published in: PloS one Vol. 9; no. 12; p. e115232
• Main Authors: Chen, Yu-Yuan, Chen, Jiann-Chu, Lin, Yong-Chin, Kitikiew, Suwaree, Li, Hui-Fang, Bai, Jia-Chin, Tseng, Kuei-Chi, Lin, Bo-Wei, Liu, Po-Chun, Shi, Yin-Ze, Kuo, Yi-Hsuan, Chang, Yu-Hsuan
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 17-12-2014; Public Library of Science (PLoS)
• Subjects: Animals; Apoptosis; Apoptosis - drug effects; Biology and Life Sciences; Biomarkers - metabolism; Blotting, Western; Cell adhesion & migration; Cell Proliferation - drug effects; Cell walls; Cells, Cultured; Crustacea; Crustaceans; Ctenopharyngodon idella; Damage patterns; Degranulation; Enzymes; Gangrene; Gel electrophoresis; Genes; Glucan; Hemocytes; Hemocytes - drug effects; Hemocytes - immunology; Hemocytes - pathology; Hostages; Immune system; Immunity; Immunity, Innate - drug effects; Immunity, Innate - immunology; Innate immunity; Invertebrates; Lipopolysaccharides; Lipopolysaccharides - pharmacology; Litopenaeus vannamei; Mitotic Index; Necrosis; Oceans; Pathogen-Associated Molecular Pattern Molecules - pharmacology; Pathogens; Pattern recognition; Penaeidae - immunology; Peptidoglycans; Phagocytes; Phagocytosis - drug effects; Phagocytosis - immunology; Phenoloxidase; Proteins; Receptors, Pattern Recognition - metabolism; Respiratory burst; Respiratory Burst - drug effects; Respiratory Burst - immunology; Rubidium; Salts; Shellfish; Sodium lauryl sulfate; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry; Tissues; Vibrio alginolyticus; Vibrio alginolyticus - drug effects; Vibrio alginolyticus - immunology; Vibrio Infections - drug therapy; Vibrio Infections - immunology; Vibrio Infections - microbiology; Waterborne diseases; Zebrafish
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0115232

Invertebrates rely on an innate immune system to combat invading pathogens. The system is initiated in the presence of cell wall components from microbes like lipopolysaccharide (LPS), β-1,3-glucan (βG) and peptidoglycan (PG), altogether known as pathogen-associated molecular patterns (PAMPs), via a recognition of pattern recognition protein (PRP) or receptor (PRR) through complicated reactions. We show herein that shrimp hemocytes incubated with LPS, βG, and PG caused necrosis and released endogenous molecules (EMs), namely EM-L, EM-β, and EM-P, and found that shrimp hemocytes incubated with EM-L, EM-β, and EM-P caused changes in cell viability, degranulation and necrosis of hemocytes, and increased phenoloxidase (PO) activity and respiratory burst (RB) indicating activation of immunity in vitro. We found that shrimp receiving EM-L, EM-β, and EM-P had increases in hemocyte count and other immune parameters as well as higher phagocytic activity toward a Vibrio pathogen, and found that shrimp receiving EM-L had increases in proliferation cell ratio and mitotic index of hematopoietic tissues (HPTs). We identified proteins of EMs deduced from SDS-PAGE and LC-ESI-MS/MS analyses. EM-L and EM-P contained damage-associated molecular patterns (DAMPs) including HMGBa, HMGBb, histone 2A (H2A), H2B, and H4, and other proteins including proPO, Rab 7 GPTase, and Rab 11 GPTase, which were not observed in controls (EM-C, hemocytes incubated in shrimp salt solution). We concluded that EMs induced by PAMPs contain DAMPs and other immune molecules, and they could elicit innate immunity in shrimp. Further research is needed to identify which individual molecule or combined molecules of EMs cause the results, and determine the mechanism of action in innate immunity.