Fish & shellfish immunology最新文献

Vaccines are of great importance to green aquaculture. In this study, the polyvalent immunoprotective activities of protein, DNA and egg yolk antibody (IgY) vaccines of Vibrio fluvialis outer membrane protein VF08100 were assessed. Carassius auratus was immunized with these three vaccines and challenged with V. fluvialis and Aeromonas hydrophila. The results showed that the three vaccines had significant immune protection rates (p < 0.01) against V. fluvialis and A. hydrophila infections, could activate the congenital immune response in C. auratus, and downregulate the expression of inflammation genes (p < 0.01) and antioxidant factors (p < 0.01) to reduce the inflammatory response and antioxidant reactions, respectively. Moreover, the three vaccines could protect the internal tissue structure integrity and reduce the apoptosis and DNA damage of kidney cells induced by bacterial infection. Therefore, the protein, DNA and IgY vaccines of VF08100 resisted multiple bacterial infections and can be used as polyvalent candidate vaccines for aquaculture.

White feces syndrome (WFS) has been one of the emerging diseases causing instructive economic losses in the penaeid shrimp aquaculture industry, though the etiology of WFS remains unclear. In this research, we have collected intestinal samples from normal and diseased shrimp (Litopenaeus vannamei) from the natural shrimp cultivation farm for histological and proteomic analysis. The preliminary pathogen detection confirmed that WFS in this study was (Enterocytozoon hepatopenaei) EHP-WFS that was related to Vibrio spp. Moreover, the destructive damage of the intestine in WFS-diseased shrimp revealed by histological observation indicated a deficiency in digestive capacity, which might be closely related to WFS. Furthermore, we have characterized 86 and 165 differentially expressed proteins (DEPs) through a non-directional integrative analysis, which were significantly up-regulated and down-regulated, respectively. The down-regulation of various digestive enzymes in the WFS-diseased shrimp was consistent with the results of intestinal histology. DEPs were enriched in the lysosome and sphingolipid metabolism pathway, indicating that they were strongly associated with the occurrence of WFS (P < 0.05). Of this, the expression of down-regulated proteins in the lysosomal pathway was further validated by real-time quantitative polymerase chain reaction (RT-qPCR). Ultimately, crustin, lipase, and glucosylceramidase (GBA), which were significantly decreased in WFS-diseased shrimp, were screened as the predictive protein signatures for the diagnosis and prevention of WFS. Consequently, our results will provide a theoretical reference for the diagnosis of EHP-WFS by the protein aspect and crustin, lipase, and GBA may be predictive signatures that are suitable for EHP-WFS.

With the expansion of the culture scale of red swamp crayfish (Procambarus clarkii), the high incidence of diseases has seriously threatened the development of its industry. In this study, PcToll3 and PcToll4 were respectively cloned and explored SNPs among the germplasm populations, which had been identified relating to disease resistance in crayfish based on our previous study. A total of 3036 bp and 2820 bp of the open reading frame of PcToll3 and PcToll4 encoded 1011 and 939 amino acids, respectively. They were specially expressed in haemolymph, and significantly up-regulated expression after stimulation by Vibrio parahaemolyticus, Aeromonas hydrophila and white spot syndrome virus. It was found that the expression of downstream genes PcALF, PcCru, PcIMD, PcMyD88, and PcNF-κB were repressed after interference of PcToll3 and/or PcToll4. Totally, 16 and 19 SNPs in the coding region of PcToll3 and PcToll4 were mined, and the favoured haplotypes and the combinations of them were classified according to the associated SNPs with the disease resistance in crayfish. The haplotypes of Toll3-Hap1, Toll4-Hap1 and the combination of Toll3+Toll4-Hap1 were further validated that they had the stronger disease resistance comparing to others haplotypes, and the related KASP markers were developed for further breeding application. This study will advance our understanding of the function of the two Toll genes in crayfish, and provide the markers for the molecular breeding.

Bivalve immunity relies exclusively on innate cellular and humoral mechanisms, during which cells named haemocytes maraud across tissues to survey the organism and cope with invaders through migration towards infected site. Immune response is therefore governed by haemocyte motility. This review focuses on the different types of haemocyte movement in Mytilus sp. to address their role in immunity, from random patrolling of organs to directed pathogen elimination. By forming cell clusters or aggregates of different sizes, haemocyte displacements define inflammation per se in mussels. Although described for many years, motility can now be quantified by advanced microscopy techniques that give access to cell velocity values, allowing us to quantify inflammation. As various biotic and abiotic factors have been found to modulate haemocyte velocity, this parameter can be considered a marker to assess the inflammation level, paving the way for future developments in determining the immune status of mussels.

Scavenger receptors (SRs) are crucial for pattern recognition in the innate immune system. However, the role of Scavenger Receptors class A member 5 (SRA5) in the immunological response of bony fish to pathogen invasion remains unclear. This study identified and characterized the SRA5 of Lateolabrax maculatus (LmSRA5) from its transcriptome database. LmSRA5 has a 1494 bp open reading frame, encodes 497 amino acids, has a molecular weight of 55.01 kDa, and contains a collagen domain and a conserved Scavenger Receptor Cysteine-Rich domain. LmSRA5 exhibited high sequence similarity to previously reported SRA5 genes. LmSRA5 exhibited high sequence similarity to previously reported SRA5 genes. LmSRA5 is primarily localized in the cytoplasm, with its encoded proteins distributed in both the cytoplasm and the cell membrane. LmSRA5 was expressed in all tissues. The highest expression was observed in the pituitary gland, with significant levels in the stomach, intestines, liver, and kidney. LmSRA5 expression in the head kidney, spleen, blood, and intestines initially increased, then decreased following infection with Aeromonas veronii. The binding affinity of LmSRA5 for A. veronii was enhanced by increasing concentrations of the extracellular domain recombinant LmSRA5. Knockdown and overexpression experiments in liver cells demonstrated that LmSRA5 significantly regulates the expression of IL-8 and c-Jun. LmSRA5 participates in the immune response by recognizing pathogen-associated molecular patterns (PAMPs) and contributes to immune regulation through modulation IL-8 and c-Jun. This study offers valuable insights into the role of SRA5 in pathogen resistance and immune regulation in bony fish, thereby contributing to the advancement of aquaculture under escalating disease pressures.

Cortisol can impact the transcription of downstream inflammation and immune-related genes via the glucocorticoid receptor (GR), thereby influencing the immune response and maintaining the homeostatic balance of the host. However, there is a lack of research on the mechanisms by which cortisol affects the immune response of Siberian sturgeon (Acipenser baerii) through GR. In this study, an anti-inflammatory state of Siberian sturgeon was established by the combined treatment of head kidney (HK) leukocytes with LPS + cortisol. Subsequently, the inflammation-related genes of the AbGR antagonistic group (LPS + cortisol + RU-486) and the AbGR non-antagonistic group (LPS + cortisol) were compared by qRT-PCR and high-throughput sequencing methods. Furthermore, an AP-1 agonist ASLAN003 was used to detect the regulatory effect of the AP-1 gene on inflammatory cytokines. The results showed that cortisol downregulated the expressions of il-1β, il-6, il-8, tnf-α, and il-17c that were induced by LPS, while simultaneously promoting the expressions of tgf-β1. Moreover, this pattern was reversed by adding RU486. When analyzing the differentially expressed genes in the transcriptome sequencing of HK leukocytes in AbGR antagonistic group, 261 significantly down-regulated genes and 194 significantly up-regulated genes were annotated. Furthermore, 26 differentially expressed genes related to inflammation in AbGR antagonistic group were enriched, and the key nuclear transcription factor AP-1 for regulating inflammation function of AbGR was selected based on the enrichment factor and p-value for subsequent research. In the HK leukocytes after cortisol + ASLAN003 treatment, the expressions of fosl1 and jund that were induced by ASLAN003 were significantly down-regulated after cortisol treatment. In this situation, the expressions of il-10 and tgf-β1 were significantly increased, and the expressions of tnf-α and cox-2 were significantly decreased after cortisol treatment. Therefore, this study demonstrated that cortisol inhibits the expression of AP-1 through GR in Siberian sturgeon, and then regulates the generation of the inflammatory response.

Autophagy plays a crucial role in innate and adaptive immunity against invading microorganisms. However, the mechanism underlying autophagy in Macrobrachium rosenbergii remains largely unknown. Here, we demonstrate that Aeromonas hydrophila activates autophagy in M. rosenbergii, according to western blot, qRT-PCR, and transmission electron microscopy observations. Rapamycin treatment to activate autophagy in M. rosenbergii followed by stimulation with A. hydrophila significantly decreased the A. hydrophila OmpA copy number in the gills of M. rosenbergii. Furthermore, high-throughput RNA-seq analysis of M. rosenbergii gills treated with rapamycin revealed 1684 upregulated and 1500 downregulated differentially expressed genes (DEGs), most of which regulate metabolic pathways. A comprehensive joint analysis of the two transcriptomic databases for A. hydrophila infection and rapamycin treatment identified 15 upregulated and 25 downregulated DEGs, respectively. These genes enhance the immune defense of M. rosenbergii by negatively regulating metabolic pathways and promoting immune pathways. Our results provide a theoretical basis for further exploration of the antibacterial mechanism of M. rosenbergii.

Although DNA vaccines hold significant potential, their practical application in aquaculture remains limited. In both mammals and teleost fish, B cells, which recognize antigens and produce antibodies, play an important role in immunity. In this study, B-cell epitopes capable of inducing fish immunity from IS701 family transposase (IS701) and molybdopterin-dependent oxidoreductase (Mol) proteins of Nocardia seriolae were screened. pcDNA-IS701 and pcDNA-Mol recombinant plasmids were constructed. The results showed that two proteins possessed multiple B-cell epitopes, and both pcDNA-IS701 and pcDNA-Mol induced innate immunity and specific antibody responses, along with increased mRNA expression levels of genes encoding humoral (MHCIIα and CD4) and cell-mediated (MHCIα and CD8α) immunity. In addition, both pcDNA-IS701 and pcDNA-Mol strengthened the protection against N. seriolae infection, with immune protection rates of 45.06% for IS701 and 61.04% for Mol, respectively. In conclusion, pcDNA-IS701 and pcDNA-Mol are candidate DNA vaccines for nocardiosis in fish.