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Chinese sucker (Myxocyprinus asiaticus), a unique species of Catostomidae in Asia and China's second-class protected animal species, has important value both in research and economy field. Moreover, Chinese sucker are susceptible to infection by Aeromonas hydrophila. However, until now the information related to the immune system against A. hydrophila of Chinese sucker is unclear. Therefore, to understand the molecular basis underlying the host immune response to A. hydrophila infection, Illumina HiSeq™ 2000 was used to analyse the spleen transcriptome of infected Chinese sucker for the first time. De nova assembly of paired-end reads yielded 693,660 unigenes. Comparative analysis of the expression profile between bacteria challenge fish and control fish identified a total of 1390 differentially expressed genes (padj<0.05 and |log2FoldChange| > 1), including 907 up-regulated genes and 483 down-regulated genes. A significant enrichment analysis of these DEGs in spleen revealed major immune-related pathways, including Toll-like receptor, T cell receptor, complement and coagulation cascades, MAPK and NF-kB. The selected DEGs were validated using qPCR. Moreover, the expression level of nineteen immune-related genes were detected at 4, 12 and 24 h post infection. The results showed that a various types of molecules were involved in the antibacterial immune response, including pattern recognition receptors (TLR2 , TLR4 , TLR6 and PGRP5), interleukins (IL1B , IL6 , IL10 , IL11 and IL12), chemokines (CXCL1 , CXCL2 and CXCL8), activity regulation molecules of immune cells (CD68 , CD200 , CD247 , CSF3 and CSF3R), and complement components (C6 , C7). Altogether, the results obtained on immune-related genes may allow for a better understanding of immunity in Chinese sucker to A. hydrophila , carrying out detailed functional analysis of these genes and developing strategies for efficient immune protection against infections in Chinese sucker, which will be great significance for healthy breeding and resource conservation of Chinese sucker. • Spleen transcriptome of Chinese sucker was sequenced by acute infection with A. hydrophila for the first time. • 693,660 unigenes were vailidated and annotated against the NR, NT, KO, SwissProt, Pfam, GO, and KOG databases. • 1,390 DEGs and 238 signaling pathways were identified between non-infected and A. hydrophila -infected fish. • The main immune related DEGs were confirmed by the quantitative PCR analysis. • This study initially revealed the immune response mechanism of Chinese sucker against A. hydrophila infection. [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]

Hand, foot, and mouth disease (HFMD) caused by enterovirus 71 (EV71) presents with a wide variety of clinical manifestations. Host immune response is a factor that influences disease susceptibility and severity. We investigated the potential association of gene polymorphisms in the pattern recognition receptor (PRR) pathway with the risk and severity of EV71 infection. A total of 180 EV71 HFMD cases (108 severe case; 72 mild cases) were enrolled. A group of 201 sex- and age-matched children was included as a control. All subjects were genotyped for the most common single-nucleotide polymorphisms (SNPs) in the PRR and the PRR signaling pathway using the SNPscan multiple SNP typing method. Binary logistic regression analysis revealed statistically significant differences in polymorphism of RIG-1 between patients and controls (rs3739674 G vs C: OR = 1.502, 95%CI: 1.120-2.014; rs9695310 G vs C: OR = 1.782, 95%CI: 1.312-2.419). Polymorphisms of RIG-1 rs3739674 (G vs C: OR = 2.047, 95%CI: 1.307-3.205) and TLR3 rs5743305 (A vs T: OR = 0.346, 95%CI: 0.212-0.566) were found to be associated with disease severity. The results indicated that RIG-1 (rs3739674 and rs9695310) polymorphisms are associated with an increased risk of EV71-induced HFMD in Chinese children, whereas RIG-1 rs3739674 and TLR3 rs5743305 polymorphisms are associated with disease severity. These findings support an important role of innate immune mechanism in EV71 infection., (© 2017 Wiley Periodicals, Inc.)