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In China, Procambarus clarkii has grown to be one of the most important cultivated crustacean species due to its excellent resistance ability against viral and bacterial infection. However, this broad-spectrum mechanism of disease resistance is less well known. In this study, a new LGBP known as Pc LGBP was cloned and described. Its full-length cDNA is 1200 bp with an open reading frame (ORF) of 1086 bp, encoding a 361 amino acid polypeptide. The transcripts of Pc LGBP were widely dispersed in P. clarkii tissues, with particularly elevated expression levels in hemocytes. Furthermore, Aeromonas hydrophila and white spot syndrome virus (WSSV) challenge dramatically increased its mRNA expression in hemocytes and gills. The purified recombinant Pc LGBP protein could bind to different kinds of pathogenic microorganisms, demonstrating a broad-spectrum pathogen recognition ability. Besides, Pc LGBP knockdown by RNA interference and r Pc LGBP injection experiments confirmed that the protein could apparently accelerate the bacterial clearance and inhibit the WSSV proliferation in vivo , thus increase the survival rate of A. hydrophila or WSSV infected P. clarkii. Further studies revealed that silencing of Pc LGBP resulted in inactivation of prophenoloxidase (proPO) system, decreased the expression levels of Toll/IMD pathway components, as well as some antimicrobial peptides (AMPs). Taken together, Pc LGBP may protect P. clarkii from diverse invading pathogens through activating the proPO system, NF-κB pathway and the expression of AMPs. These findings would contribute to the exploration of the crustacean immunity regulatory mechanisms and hold potential for the disease resistance breeding of P. clarkii. • A novel member of LGBP family named Pc LGBP was identified in Procambarus clarkii. • Pc LGBP was involved in both anti-bacterial and anti-viral immune response. • Pc LGBP exhibited broad-spectrum resistance ability in vivo. • Pc LGBP participate in the activation of the proPO system and NF-κB pathway. [ABSTRACT FROM AUTHOR]

The disease caused by duck Tembusu virus (DTMUV) is characterized by severe egg-drop in laying ducks. Currently, the disease has spread to most duck-raising areas in China, leading to great economic losses in the duck industry. In the recent years, DTMUV has raised some concerns, because of its expanding host range and increasing pathogenicity, as well as the potential threat to public health. Innate immunity is crucial for defending against invading pathogens in the early stages of infection. Recently, studies on the interaction between DTMUV and host innate immune response have made great progress. In the review, we provide an overview of DTMUV and summarize current advances in our understanding of the interaction between DTMUV and innate immunity, including the host innate immune responses to DTMUV infection through pattern recognition receptors (PRRs), signaling transducer molecules, interferon-stimulated genes (ISGs), and the immune evasion strategies employed by DTMUV. The aim of the review is to gain an in-depth understanding of DTMUV pathogenesis to facilitate future studies. [ABSTRACT FROM AUTHOR]

The innate immune system is the first line of defense protecting the hosts against invading pathogens. Mud crab (Scylla paramamosain) is widely distributed in China and Indo-west Pacific countries, which develops a very complicated innate immune system against pathogen invasions. Innate immunity involves the humoral and cellular responses that are linked to the pattern recognition receptors (PRRs). PRRs initially recognize the infection and trigger the activation of signaling cascades, leading to transcriptional regulation of inflammatory mediators that function in pathogenic control and clearance. In mud crab S. paramamosain , the Toll/Toll-like receptors, lipopolysaccharide and β-1,3-glucan binding proteins, C-type lectins, scavenger receptors, and down syndrome cell adhesion molecules have been identified as receptor families responsible for the recognition of bacteria, fungi, and viruses, and are important components in the innate immune system. In this review, we summarize the literature on the current knowledge and the roles of PRRs in the immune defenses of mud crab, which in an effort to provide much information for further researches. • Five pattern recognition receptors (PRRs) have been reported in mud crab. • Different PRRs target to different ligands in the innate immunity. • PRRs activate the intracellular signaling cascades and subsequently respond to the infections. [ABSTRACT FROM AUTHOR]