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1.
Differences in susceptibility to the myxozoan parasite Tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease (PKD), between four strains of rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta) were evaluated. Fish were exposed to water enzootic for the parasite in the field for 5 days and were subsequently transferred to the laboratory. Relative parasite load was determined after 2, 3 and 4 weeks post-exposure (wpe) by quantitative real-time PCR (qPCR) of kidney samples and number of parasite stages was determined in immunohistochemical stained sections of kidney, liver and spleen tissues. According to qPCR results, the highest amount of parasite DNA per equal amount of host tissue at all time points was measured in brown trout. Two of the rainbow trout strains showed lower relative parasite load than all other groups at the beginning of the experiment, but the parasite multiplied faster in these strains resulting in an equal level of relative parasite load for all rainbow trout strains at 4 wpe. A weak negative correlation of fish size and parasite load was detected. Only in samples of a few fish, single stages of T. bryosalmonae were found in sections stained by immunohistochemistry impeding quantitative evaluation of parasite numbers by this method. The results indicate a differential resistance to T. bryosalmonae between the rainbow trout strains investigated and between rainbow trout and brown trout.  相似文献   

2.
Abstract

Blood parameters, disease resistance, and the immune response were sequentially evaluated in rainbow trout Oncorhynchus mykiss with proliferative kidney disease (PKD). The fish were maintained under laboratory conditions, and the study group went through a full cycle of the disease. Hematological and serological changes occurred primarily in those fish with severe kidney lesions. Fish infected with the parasite that causes PKD demonstrated a greater resistance to bacterial challenge, and their immune responses were heightened when compared with those of uninfected fish. These data suggest that PKD alone is not a predisposing factor for secondary infections if the fish does not incur severe renal lesions.  相似文献   

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4.
Haemophilus parasuis is the causative agent of Glässer's disease in pigs, a severe systemic disease that has led to increasing economic losses in the pig industry worldwide. The H. parasuis genome sequence has been completed, but the function and essentiality of the annotated genes remain largely unknown, especially virulence factors. The recent developments in the efficient genetic manipulation of H. parasuis have greatly facilitated the study of gene function, pathogenesis mechanisms and virulence factors. In this review, we provided update information regarding that (i) how the pathogen overcome host immune responses and cell barriers which were tightly associated with the pathogenesis, and (ii) the several recent identification of virulence factors were involved in evading the immune responses and cell barriers in H. parasuis.  相似文献   

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6.
Conglutinin is a high molecular-weight lectin originally detected in bovine serum. It belongs to the family of collectins that bind sugar residues in a Ca2+-dependent manner and are effector molecules in innate immunity. Conglutinin appears to play an important role in immune defense mechanisms, showing antiviral and antibacterial activities when tested in vivo and in vitro. The present study evaluated the effect of conglutinin on the respiratory bursts in bovine peripheral phagocytes. Using nitroblue tetrazolium and hydrogen peroxide assays, we showed that sugar ligand-bound conglutinin stimulated the production of superoxide and H2O2 in granulocytes whereas the non-sugar-bound form of conglutinin inhibited these processes. These results indicate that both forms of conglutinin are able to interact with surface leukocyte receptors but have opposite effects on phagocytic activity. Our findings suggest that conglutinin bound to sugar residues on microbial surfaces can induce oxygen burst in phagocytes, and thereby mediates the elimination of pathogens and prevents the spread of infection.  相似文献   

7.
Among many of the pathogens, virus is the main cause of diseases in livestock and poultry. A host infected with the virus triggers a series of innate and adaptive immunity. The realization of innate immune responses involves the participation of a series of protein molecules in host cells, including receptors, signal molecules and antiviral molecules. Post-translational modification of cellular proteins by ubiquitin regulates numerous cellular processes, including innate immune responses. Ubiquitin-mediated control over these processes can be reversed by cellular or viral deubiquitinases (DUBs). DUBs have now been identified in diverse viral lineages, and their characterization is providing valuable insights into virus biology and the role of the ubiquitin system in host antiviral mechanisms. In this review, we briefly introduce the mechanisms of ubiquitination and deubiquitination, present antiviral innate immune response and its regulation by ubiquitin, and summarize the prevalence of DUBs encoded by viruses (Arteriviridae, Asfarviridae, Nairoviridae, Coronaviridae, Herpesviridae, and Picornaviridae) infecting domestic animals and poultry. It is found that these DUBs suppress the innate immune responses mainly by affecting the production of type I interferon (IFN), which causes immune evasion of the viruses and promotes their replication. These findings have important reference significance for understanding the virulence and immune evasion mechanisms of the relevant viruses, and thus for the development of more effective prevention and treatment measures.  相似文献   

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9.
Abstract

An outbreak of proliferative kidney disease affecting farmed California golden trout Oncorhynchus mykiss aguabonita in the United Kingdom is described. The fish displayed the clinical signs of the disease, such as characteristic swelling of the posterior kidney and spleen. Confirmation of infection with Tetracapsuloides bryosalmonae in the renal tissue was done by means of electron microscopy and immunohistochemistry using a monoclonal antibody specific to T. bryosalmonae.  相似文献   

10.
Betanodaviruses are the causative agents of viral nervous necrosis (VNN), a serious disease of cultured marine fish worldwide. Virus-like particles (VLPs) are one of the good novel vaccine candidates to control this disease. Until now, betanodavirus vaccine studies mainly focused on the humoral immune response and mortality after virus challenge. However, little is known about the activation of genes responsible for cellular and innate immunity by vaccines. In the present study, VLPs of orange-spotted grouper nervous necrosis virus (OGNNV) were produced in prokaryotes and their ability to enter Asian sea bass cells was the same as native virus, suggesting that they possess a similar structure to OGNNV. VLPs immunogenicity was then determined by intramuscularly vaccinating Epinephelus coioides at different concentrations (1.5 or 15 μg g?1 fish body weight, FBW) and immunizing frequencies (administration once, twice and thrice). A single vaccination with the dosage of 1.5 μg g?1 FBW is enough to provoke high titer antibodies (average 3 fold higher than that of negative control) with strong neutralizing antibody titer as early as 1 week post immunization. Furthermore, quantitative PCR analysis revealed that eleven genes associated with humoral, cellular and innate immunities were up-regulated in the liver, spleen and head kidney at 12 h post immunization, correlating with the early antibody response. In conclusion, we demonstrated that VLP vaccination induced humoral immune responses and activated genes associated with cellular and innate immunity against betanodavirus infection in orange-spotted grouper.  相似文献   

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12.
Brucella spp. are Gram-negative, coccobacillary, facultative intracellular pathogens. B. abortus strain 2308 is a pathogenic strain affecting cattle and humans. Rough B. abortus strain RB51, which lacks the O-side chain of lipopolysaccharide (LPS), is the live attenuated USDA approved vaccine for cattle in the United States. Strain RB51SOD, which overexpresses Cu–Zn superoxide dismutase (SOD), has been shown to confer better protection than strain RB51 in a murine model. Protection against brucellosis is mediated by a strong CD4+ Th1 and CD8+ Tc1 adaptive immune response. In order to stimulate a robust adaptive response, a solid innate immune response, including that mediated by dendritic cells, is essential. As dendritic cells (DCs) are highly susceptible to Brucella infection, it is possible that pathogenic strains could limit the innate and thereby adaptive immune response. By contrast, vaccine strains could limit or bolster the innate and subsequent adaptive immune response. Identifying how Brucella vaccines stimulate innate and adaptive immunity is critical for enhancing vaccine efficacy. The ability of rough vaccine strains RB51 and RB51SOD to stimulate DC function has not been characterized. We report that live rough vaccine strain RB51 induced significantly better (p ≤ 0.05) DC maturation and function compared to either strain RB51SOD or smooth virulent strain 2308, based on costimulatory marker expression and cytokine production.  相似文献   

13.
This study demonstrates the feasibility of using goldfish as an infection model to investigate the pathogenesis of Edwardsiella piscicida. Goldfish were found to be susceptible to acute E. piscicida-induced disease and died in a dose-dependent manner. E. piscicida was further shown to replicate rapidly in the head kidneys and livers of infected goldfish from 1 d post-injection, and bacteria numbers were significantly decreased 5 d post-injection. Immune responses were successfully induced in goldfish injected with E. piscicida strains and 60% of goldfish inoculated with an attenuated E. piscicida strain were found to survive subsequent injection with a pathogenic strain. The results of differential leukocyte count experiments suggested that leukocytes were immediately recruited as an innate immune response against the infection. Thus, this well-characterized goldfish species is a suitable infection model for studying E. piscicida pathogenesis, and might be applicable to research on other fish diseases.  相似文献   

14.
Our understanding of the innate immune response in the horse has been limited by a lack of definitive data concerning cell signaling in response to microbial products. Toll-like receptors (TLRs) recognize conserved molecular motifs of microbes and elicit immune responses through their coupling with intracellular adaptor molecules, particularly MyD88 and TRIF. To provide a more definitive characterization of TLR signaling in the horse, the objectives of this study were to: (1) characterize the responses of equine monocytes to TLR ligands that signal through MyD88, TRIF or both in other species, and (2) determine the profiles of gene expression initiated utilizing these adaptor molecules. Monocytes were used to establish concentration response curves for Escherichia coli lipopolysaccharide (LPS; TLR4 ligand) and N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-[R]-cysteinyl-[S]-seryl-[S]-lysyl-[S]-lysyl-[S]-lysyl-[S]-lysine x 3 HCl (Pam3CSK4; TLR2 ligand) based on expression of procoagulant activity (PCA) and production of tumor necrosis factor-alpha (TNF-α); effects of polyinosine–polycytidylic acid (Poly I:C; TLR3 ligand) were determined by quantifying expression of mRNA for interferon-beta (IFN-ß). Expression of genes associated with the MyD88- (TNF-α, IL-1ß, IL-6 and IL-10) and TRIF-dependent pathways (IFN-ß, IP-10, RANTES and TRAF1) were measured at intervals spanning 20 h. LPS and Pam3CSK4 induced significantly higher expression of TNF-α, IL-1ß, and IL-10 than did Poly I:C. Poly I:C induced significantly higher expression of IFN-ß, IP-10 and RANTES than did either the TLR2 or TLR4 ligands. High concentrations of E. coli LPS did not significantly increase expression of genes associated with the TRIF-dependent pathway. The results of this study suggest that equine monocytes utilize a common intracellular pathway in response to TLR2 and TLR4 ligands, but a distinct pathway in response to TLR3 ligands.  相似文献   

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16.
Denileukin Diftitox (ONTAK®, DAB389 IL-2) is a recombinant DNA-derived fusion protein depleting cells that express high-affinity IL-2 receptor. Important cell targets are CD4+CD25+Foxp3+ regulatory T cells (Treg). Elimination of immunosuppressive Treg by Denileukin Diftitox may provide a way to modulate immune tolerance following stem cell transplantation. Here, we combined Treg depletion with a vaccination approach to induce donor-specific immune reactions. To investigate this approach we chose the mixed chimerism canine stem cell transplantation model which represents a high state of tolerance between two hematopoietic systems. The aim was therefore to induce a graft versus hematopoiesis effect thereby converting mixed to full donor chimerism. Dog leukocyte antigen identical siblings that had developed a stable mixed chimerism after non-myeloablative stem cell transplantation received a single dose of Denileukin Diftitox (18 μg/kg, i.v.) followed by several cell-lysate vaccinations. Host peripheral blood mononuclear cell lysates combined with CpG-ODN, and Montanide® ISA 51 were locally applied. In vitro studies demonstrated that canine Treg are a target of Denileukin Diftitox. The suppression of T-cell proliferation by Treg was abolished by addition of Denileukin Diftitox (10 nM). An increase of proliferation of median 300% (range: 200%–425%) was observed. No change in donor chimerism was observed after administration of Denileukin Diftitox and vaccination. This study highlights that application of Denileukin Diftitox resulted in a depletion of Treg followed by an increase of immune response in vitro. This effect could not be confirmed in vivo even if the immune system was stimulated by vaccinations.  相似文献   

17.
The objective of this study was to evaluate precision and establish a reference range in healthy guinea pigs for total plasma thyroxine (T4) using a point-of-care analyzer. One-hundred-nine (109) healthy pet and laboratory-housed guinea pigs were included in this study in which plasma T4 concentrations were measured on a point-of-care analyzer. Some of the samples were analyzed in duplicate and then compared using an intraclass correlation coefficient (ri) and coefficient of variance to assess precision. Statistical analysis was performed to test for normal distribution of data and a reference range was established. Differences in subsets of the tested population were evaluated using t tests and analysis of variance. The ri was 0.95 and the coefficient of variance was 4.2%. Data were normally distributed and a reference range for plasma T4 of 2.26 μg/dL to 5.82 μg/dL was established. No significant differences between or among mean plasma T4 concentrations were found when sexes, housing type, and sampling protocol were compared. In addition, no significant difference was found between the mean plasma T4 concentrations of 2 age groups (2 months and 8 months). The overall precision of this testing modality was determined to be excellent, indicating that measuring plasma T4 with enzyme immunoassay on the point-of-care analyzer yields consistently repeatable results. This study successfully defined plasma T4 reference intervals specific to a point-of-care analyzer in normal guinea pigs. Our results showed that age (2 months and 8 months), sex, housing type, and sampling protocol have no significant effect on the mean plasma T4, although pet-housed guinea pigs had a wider reference interval than laboratory-housed guinea pigs.  相似文献   

18.
RT-qPCR can be used to accurately determine expression levels of genes following RNA extraction from tissue samples. If blood is the source of total RNA, it is often desirable to process the samples immediately following collection because delays in processing for RNA extraction may influence mRNA expression estimates obtained from RT-qPCR analyses. However, this may not be feasible if the site of blood collection is distant from the processing laboratory. In the present study, the effects of delays in the processing of blood samples on mRNA expression data was investigated using a panel of 23 functionally diverse genes from five different gene ontology (GO) categories in peripheral blood sampled from ten age-matched healthy cattle. Venous blood was collected in Tempus? Blood RNA tubes, which contain reagents that lyse blood cells immediately and stabilise the RNA signature (T0). Blood was also collected in conventional lithium heparin collection tubes, and stored at ambient temperature for T4, T6 and T8 h, prior to total RNA extraction. The mRNA expression profiles of these 23 genes were determined by RT-qPCR and compared across the time course. Thirteen genes showed significant up- or down-fold changes in mRNA expression over the 8 h time course. Among the GO categories, genes in the Immune response category showed the most differential expression. These results also demonstrated that the changes in mRNA expression for the IFNG gene, which encodes the cytokine IFN-γ, did not correspond to IFN-γ protein levels estimated using ELISA.  相似文献   

19.
The analysis of CpG ODN induced innate immune responses in different animal species has shown substantial similarities and differences in levels and types of induced cytokines profile. The objectives of these studies were to identify innate immune biomarkers activated by three classes of CpG ODNs in pigs. For this purpose, we investigated the kinetics of innate immune responses in immune cells from pigs following in vitro and in vivo stimulation with CpG ODNs. The mRNA expression of cytokine and chemokine genes were assayed by SYBR@ green based quantitative real time PCR. A-class CpG ODN induced significant but transient levels of IFN-γ, IL-12 (P40), IL-6, IL-4 and TNF-α mRNA, C-class CpG ODN induced significant level of IFN-γ, IFN-α and IL-12 mRNA and the lowest level of IL-4 (Th-2 type) mRNA. A very low level of some cytokines stimulation was observed by GC ODNs. It is noteworthy, that IL-12 (P35) mRNA was significantly stimulated by B-class GpC ODN 7909. Interestingly, all classes of CpG ODNs induced significant level of IP-10 at 12 h post stimulation. These in vitro and in vivo observations suggest that interferon-γ inducible protein 10 (IP-10) may be a reliable biomarker for immune activity induced by CpG ODNs in pigs.  相似文献   

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