An assessment of immunostimulants as Mx inducers in Atlantic salmon (Salmo salar L.) parr and the effect of temperature on the kinetics of Mx responses

Salinas, Irene; Lockhart, K.; Bowden, Timothy J.; Collet, Bertrand; Secombes, Christopher J.; Ellis, A.E.

doi:10.1016/j.fsi.2004.01.003

Cited by 55 publications

(37 citation statements)

References 39 publications

(57 reference statements)

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“…These results are consistent with the few studies carried out on fish treated with β-glucan, where mx expression was increased and conferred protection to virus infection [9], [10] and [25]. For example, Kim et al [9] observed that grass carp challenged with grass carp haemorrhage virus (GCHV) presented higher and prolonged levels of mx expression together with 3 times higher fish survival rates when injected with β-glucan derived from Poria cocos 85 mycelia 15 days prior to infection.…”

Section: Discussionsupporting

confidence: 86%

“…In a more recent study [10], groups of Pacific herring (C. pallasii) that were fed with β-glucan containing diets for 40 days had approximately double the survival rates of the control groups after challenge with viral haemorrhagic septicaemia rhabdovirus (VHSV). In Atlantic salmon (Salmo salar) [25], gene expression of mx was determined in response to administration of PAMPs including β-glucan and it was shown that the latter had no effect on mx expression. This supports the observations made by Kim et al [9] and the work described herein, which revealed that another stimuli such as virus [9] or poly(I:C), respectively, are needed to induce the expression of mx.…”

Section: Discussionmentioning

confidence: 99%

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β-Glucan-supplemented diets increase poly(I:C)-induced gene expression of Mx, possibly via Tlr3-mediated recognition mechanism in common carp (Cyprinus carpio)

Falcó

Miest

Pionnier

et al. 2014

Fish & Shellfish Immunology

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Highlights•mx expression was stable or slightly up-regulated in carp after β-glucan treatment.•Poly(I:C) markedly increased mx expression in samples from β-glucan fed fish.•Two sequences for carp tlr3 were retrieved (tlr3.1 and tlr3.2) and characterized.•β-Glucan-supplemented diets increased the transcript levels of both tlr3 genes. AbstractWe have previously observed that in common carp (Cyprinus carpio), administration of β-glucan (MacroGard®) as feed additive leads to a lower expression of pro-inflammatory cytokines suggesting that this immunostimulant may be preventing an acute and potentially dangerous response to infection, particularly in the gut. However, in general, mechanisms to detect and eliminate pathogens must also be induced in order to achieve an efficient clearance of the infection. Protection against viral diseases acquired through β-glucan-supplemented feed has been extensively reported for several experimental models in fish but the underlining mechanisms are still unknown. Thus, in order to better characterize the antiviral action induced by β-glucans in fish, MacroGard® was administered daily to common carp in the form of supplemented commercial food pellets. Carp were fed for a period of 25 days prior to intra-peritoneal injection with polyinosinic:polycytidylic acid (poly(I:C)), a well-known double-stranded RNA mimic that triggers a type-I interferon (IFN) response. Subsequently, a set of immune related genes, including mx, were analysed by real-time PCR on liver, spleen, head kidney and mid gut tissues. Results obtained confirmed that treatment with β-glucan alone generally down-regulated the mRNA expression of selected cytokines when compared to untreated fish, while mx gene expression remained stable or was slightly up-regulated. Injection with poly(I:C) induced a similar down-regulated gene expression pattern for cytokines in samples from β-glucan fed fish. In contrast, poly(I:C) injection markedly increased mx gene expression in samples from β-glucan fed fish but hardly in samples from © 2014. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ fish fed control feed. In an attempt to explain the high induction of mx, we studied Toll-like receptor 3 (TLR3) gene expression in these carp. TLR3 is a prototypical pattern recognition receptor considered important for the binding of viral double-stranded RNA and triggering of a type-I IFN response. Through genome data mining, two sequences for carp tlr3 were retrieved (tlr3.1 and tlr3.2) and characterized. Constitutive gene expression of both tlr3.1 and tlr3.2 was detected by real-time PCR in cDNA of all analysed carp organs. Strikingly, 25 days after β-glucan feeding, very high levels of tlr3.1 gene expression were observed in all analysed organs, with the exception of the liver. Our data suggest that β-glucan-mediated protection against viral diseases could be due to an increased Tlr3-mediated recognition of ligands, resulting in an increased antiviral activity of Mx.

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Section: Discussionsupporting

confidence: 86%

Section: Discussionmentioning

confidence: 99%

β-Glucan-supplemented diets increase poly(I:C)-induced gene expression of Mx, possibly via Tlr3-mediated recognition mechanism in common carp (Cyprinus carpio)

Falcó

Miest

Pionnier

et al. 2014

Fish & Shellfish Immunology

View full text Add to dashboard Cite

show abstract

“…Studies in Atlantic halibut [6] detected a more stable and longer Mx response after IPNV or poly I:C injection at 8 (C (up to 7 days) when compared to the response recorded in salmonids at 12 (C (disappeared after day 4) [3,5]. In Atlantic salmon parr, Mx mRNA expression persisted for at least 21 days after injection with poly I:C at 6 (C compared with 6 days at 14 (C, though there was no apparent difference in the onset of the response [23].…”

Section: Introductionmentioning

confidence: 76%

“…However, the ability of LPS to induce Mx responses has not been demonstrated in fish. Indeed, absence of an Mx response has been reported in Atlantic salmon injected with Salmonella typhimurium LPS [5] and with Escherichia coli LPS [22,23]. Nevertheless, induction of Mx expression has been demonstrated in Atlantic salmon parr following injection of a vibrio bacterin [23] but the bacterial components, possibly the LPS or the DNA, responsible for this were not investigated.…”

Section: Introductionmentioning

confidence: 99%

Mx expression in Atlantic salmon (Salmo salar L.) parr in response to Listonella anguillarum bacterin, lipopolysaccharide and chromosomal DNA

Acosta

Lockhart

Gahlawat

et al. 2004

Fish & Shellfish Immunology

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“…The Mx:b-actin ratio on day 3 post-injection in fish with pathological livers was similar to individuals with a normal liver. The mechanism for this pathological effect is not known but it was observed also in parr held at 6 (C [12] and it is reported that in mammals, both dsRNA and interferon responses can activate the apoptotic pathway in cells [13,14]. However, the reasons as to why this apoptotic response was only found in post-smolts and not in parr or growers, and why it was seen in parr at 6 (C and not at 14 (C [12], remain to be investigated.…”

Section: Discussionmentioning

confidence: 99%

Poly I:C-induced Mx responses in Atlantic salmon parr, post-smolts and growers

Lockhart

Bowden

Ellis

2004

Fish & Shellfish Immunology

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An assessment of immunostimulants as Mx inducers in Atlantic salmon (Salmo salar L.) parr and the effect of temperature on the kinetics of Mx responses

Cited by 55 publications

References 39 publications

β-Glucan-supplemented diets increase poly(I:C)-induced gene expression of Mx, possibly via Tlr3-mediated recognition mechanism in common carp (Cyprinus carpio)

β-Glucan-supplemented diets increase poly(I:C)-induced gene expression of Mx, possibly via Tlr3-mediated recognition mechanism in common carp (Cyprinus carpio)

Mx expression in Atlantic salmon (Salmo salar L.) parr in response to Listonella anguillarum bacterin, lipopolysaccharide and chromosomal DNA

Poly I:C-induced Mx responses in Atlantic salmon parr, post-smolts and growers

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