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Valdenegro-Vega VA, Polinski M, Bridle A, Crosbie P, Leef M, Nowak BF. Effects of single and repeated infections with Neoparamoeba perurans on antibody levels and immune gene expression in Atlantic salmon (Salmo salar). FISH & SHELLFISH IMMUNOLOGY 2015; 42:522-529. [PMID: 25433137 DOI: 10.1016/j.fsi.2014.11.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 11/17/2014] [Accepted: 11/21/2014] [Indexed: 06/04/2023]
Abstract
Amoebic gill disease (AGD) is the main health problem for the salmon industry in Tasmania, Australia and is now reported in most salmon producing countries. Antibody and gene expression responses to the pathogen, Neoparamoeba perurans, have been studied independently following primary exposure; however, the effects of sequential reinfection, which can often occur during net-pen culture of salmon, remain unclear. The association between the transcription of immunoglobulin (Ig) and their systemic and mucosal antibody levels in regards to AGD is unknown. Herein, we assessed the antibody responses as well as Ig transcription in the gills of Atlantic salmon infected only once and also sequentially with N. perurans. After four successive AGD challenges, no significant differences in plasma or skin mucus levels of IgM were observed between AGD-naïve and challenged fish. However, IgM gene expression in gill lesions of AGD-affected fish increased up to 31 d after infection, while no changes in IgT, TCR and CD8 transcription were observed. Changes at IgM transcription level did not match the lack of antibody response in mucus, which is possibly explained by weak correlations existing between protein and mRNA abundances in cells and tissues. In the second experiment, which investigated Ig responses to AGD at the transcriptional as well as antibody production level in salmon after a single infection, the levels of serum or skin mucus IgM antibody were not affected and no changes in the IgM or IgT transcription were induced.
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Affiliation(s)
- Victoria A Valdenegro-Vega
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Locked Bag 1370, Launceston, Tasmania 7250, Australia.
| | - Mark Polinski
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Locked Bag 1370, Launceston, Tasmania 7250, Australia
| | - Andrew Bridle
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Locked Bag 1370, Launceston, Tasmania 7250, Australia
| | - Philip Crosbie
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Locked Bag 1370, Launceston, Tasmania 7250, Australia
| | - Melanie Leef
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Locked Bag 1370, Launceston, Tasmania 7250, Australia
| | - Barbara F Nowak
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Locked Bag 1370, Launceston, Tasmania 7250, Australia
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Nowak B, Valdenegro-Vega V, Crosbie P, Bridle A. Immunity to amoeba. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 43:257-267. [PMID: 23921258 DOI: 10.1016/j.dci.2013.07.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 07/02/2013] [Accepted: 07/28/2013] [Indexed: 06/02/2023]
Abstract
Amoebic infections in fish are most likely underestimated and sometimes overlooked due to the challenges associated with their diagnosis. Amoebic diseases reported in fish affect either gills or internal organs or may be systemic. Host response ranges from hyperplastic response in gill infections to inflammation (including granuloma formation) in internal organs. This review focuses on the immune response of Atlantic salmon to Neoparamoeba perurans, the causative agent of Amoebic Gill Disease (AGD).
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Affiliation(s)
- Barbara Nowak
- NCMCRS, AMC, University of Tasmania, Launceston, Tasmania, Australia.
| | | | - Philip Crosbie
- NCMCRS, AMC, University of Tasmania, Launceston, Tasmania, Australia
| | - Andrew Bridle
- NCMCRS, AMC, University of Tasmania, Launceston, Tasmania, Australia
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Pennacchi Y, Leef MJ, Crosbie PBB, Nowak BF, Bridle AR. Evidence of immune and inflammatory processes in the gills of AGD-affected Atlantic salmon, Salmo salar L. FISH & SHELLFISH IMMUNOLOGY 2014; 36:563-570. [PMID: 24378682 DOI: 10.1016/j.fsi.2013.12.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 11/29/2013] [Accepted: 12/18/2013] [Indexed: 06/03/2023]
Abstract
Amoebic gill disease (AGD) is a disease caused by the ectoparasite Neoparamoeba perurans which affects several cultured marine fish worldwide. The characterisation of pro-inflammatory and immune related genes at the mRNA level in AGD-affected Atlantic salmon gills was performed at 10 days post-inoculation using 2D quantitative RT-PCR, a method of mapping transcriptional responses in tissues. The genes of interest were IL-1β, TNF-α, TCR-α chain, CD8, CD4, MHC-IIα, MHC-I, IgM and IgT. A significant increase in expression of the mRNA of all the genes was observed in the gills of AGD-affected fish. Contrary to previous studies, our data suggest that the parasite, N. perurans, elicits a classical inflammatory response in the gills of AGD-affected fish and indicates that the mRNA expression of immune genes within gill lesions misrepresents the cellular immune response in the gills during AGD.
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Affiliation(s)
- Y Pennacchi
- National Centre for Marine Conservation and Resource Sustainability, Australian Maritime College, University of Tasmania, Launceston, Australia
| | - M J Leef
- National Centre for Marine Conservation and Resource Sustainability, Australian Maritime College, University of Tasmania, Launceston, Australia
| | - P B B Crosbie
- National Centre for Marine Conservation and Resource Sustainability, Australian Maritime College, University of Tasmania, Launceston, Australia
| | - B F Nowak
- National Centre for Marine Conservation and Resource Sustainability, Australian Maritime College, University of Tasmania, Launceston, Australia
| | - A R Bridle
- National Centre for Marine Conservation and Resource Sustainability, Australian Maritime College, University of Tasmania, Launceston, Australia.
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Taylor RS, Crosbie PB, Cook MT. Amoebic gill disease resistance is not related to the systemic antibody response of Atlantic salmon, Salmo salar L. JOURNAL OF FISH DISEASES 2010; 33:1-14. [PMID: 19943840 DOI: 10.1111/j.1365-2761.2009.01108.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Amoebic gill disease (AGD) is a proliferative gill tissue response caused by Neoparamoeba perurans and is the main disease affecting Australian marine farmed Atlantic salmon. We have previously proposed that macroscopic gill health ('gill score') trajectories and challenge survival provide evidence of a change in the nature of resistance to AGD. In order to examine whether the apparent development of resistance was because of an adaptive response, serum was sequentially sampled from the same individuals over the first three rounds of natural AGD infection and from survivors of a subsequent non-intervention AGD survival challenge. The systemic immune reaction to 'wildtype'Neoparamoeba sp. was characterized by Western blot analysis and differentiated to putative carbohydrate or peptide epitopes by periodate oxidation reactions. The proportion of seropositive fish increased from 46% to 77% with each AGD round. Antibody response to carbohydrate epitope(s) was immunodominant, occurring in 43-64% of samples. Antibodies that bound peptide epitope were identified in 16% of the challenge survivors. A 1:50 (single-dilution) enzyme-linked immunosorbent assay confirmed a measurable immune titre in 13% of the survivors. There was no evidence that antibodies recognizing wildtype Neoparamoeba provided significant protection against AGD.
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Affiliation(s)
- R S Taylor
- CSIRO National Food Futures Flagship, CSIRO Marine and Atmospheric Research, Hobart, Tas. 7001, Australia.
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Alvarez-Pellitero P. Fish immunity and parasite infections: from innate immunity to immunoprophylactic prospects. Vet Immunol Immunopathol 2008; 126:171-98. [DOI: 10.1016/j.vetimm.2008.07.013] [Citation(s) in RCA: 243] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Revised: 07/22/2008] [Accepted: 07/25/2008] [Indexed: 10/21/2022]
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Wynne JW, O'Sullivan MG, Stone G, Cook MT, Nowak BF, Lovell DR, Taylor RS, Elliott NG. Resistance to amoebic gill disease (AGD) is characterised by the transcriptional dysregulation of immune and cell cycle pathways. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2008; 32:1539-1560. [PMID: 18621418 DOI: 10.1016/j.dci.2008.05.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2008] [Revised: 05/03/2008] [Accepted: 05/21/2008] [Indexed: 05/26/2023]
Abstract
Amoebic gill disease (AGD) is a parasite-mediated proliferative gill disease capable of affecting a range of teleost hosts. While a moderate heritability for AGD resistance in Atlantic salmon has been reported previously, the mechanisms by which individuals resist the proliferative effects remain poorly understood. To gain more knowledge of this commercially important trait, we compared gill transcriptomes of two groups of Atlantic salmon, one designated putatively resistant, and one designated putatively susceptible to AGD. Utilising a 17k Atlantic salmon cDNA microarray we identified 196 transcripts that were differentially expressed between the two groups. Expression of 11 transcripts were further examined with real-time quantitative RT-PCR (qPCR) in the AGD-resistant and AGD-susceptible animals, as well as non-infected naïve fish. Gene expression determined by qPCR was in strong agreement with the microarray analysis. A large number of differentially expressed genes were involved in immune and cell cycle responses. Resistant individuals displayed significantly higher expression of genes involved in adaptive immunity and negative regulation of the cell cycle. In contrast, AGD-susceptible individuals showed higher expression of acute phase proteins and positive regulators of the cell cycle. Combined with the gill histopathology, our results suggest AGD resistance is acquired rather than innately present, and that this resistance is for the most part associated with the dysregulation of immune and cell cycle pathways.
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Affiliation(s)
- James W Wynne
- CSIRO National Food Futures Flagship, CSIRO Marine and Atmospheric Research Hobart, GPO Box 1538, Hobart, Tasmania 7001, Australia.
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Bridle AR, Morrison RN, Nowak BF. The expression of immune-regulatory genes in rainbow trout, Oncorhynchus mykiss, during amoebic gill disease (AGD). FISH & SHELLFISH IMMUNOLOGY 2006; 20:346-64. [PMID: 16006146 DOI: 10.1016/j.fsi.2005.05.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Amoebic gill disease (AGD) is an ectoparasitic disease caused by infection with the protozoan Neoparamoeba sp. and is characterised by epithelial hyperplasia that manifests as gill lesions. In order to examine the nature of the immune response to AGD, the expression of a range of immune-regulatory genes was examined in naïve uninfected rainbow trout, Oncorhynchus mykiss, and naïve rainbow trout subjected to a laboratory-induced AGD infection. The immune-regulatory genes examined were interleukin-1 beta isoform 1 (IL-1beta1), tumour necrosis factor alpha isoforms 1 and 2 (TNF-alpha1, TNF-alpha2), interleukin-8 (IL-8), transforming growth factor beta isoform 1 (TGF-beta1), inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), major histocompatibility complex beta chain (MHC-II beta-chain) and T-cell receptor beta chain (TCR beta-chain). Immune-regulatory genes that were up/down-regulated in AGD-infected trout compared to uninfected controls at 0, 7, and 14 days post-inoculation (p.i.) in gill, liver and anterior kidney tissue were initially identified by means of semi-quantitative RT-PCR. Up/down-regulated immune-regulatory genes were subsequently quantitated and validated by real-time RT-PCR (qRT-PCR). The extent of AGD-associated pathology was consistent amongst all AGD-infected trout at 7 days p.i. and increased considerably by 14 days p.i. At both 7 and 14 days p.i. IL-1beta1 and iNOS gene expression was significantly up-regulated in the gills, and IL-8 was significantly up-regulated in the liver of AGD-infected trout at 7 days p.i. These data demonstrate the involvement of the immune response to AGD at the molecular level, and indicate the importance of this response at the site of infection and the possible involvement of a systemic immune response.
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Affiliation(s)
- Andrew R Bridle
- School of Aquaculture, Tasmanian Aquaculture and Fisheries Institute and Aquafin CRC, University of Tasmania, Locked Bag 1370, Launceston 7250, Tasmania, Australia.
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Douglas-Helders M, Nowak B, Butler R. The effect of environmental factors on the distribution of Neoparamoeba pemaquidensis in Tasmania. JOURNAL OF FISH DISEASES 2005; 28:583-92. [PMID: 16302952 DOI: 10.1111/j.1365-2761.2005.00647.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Aquaculture in Tasmania is mostly carried out in estuaries. These estuarine habitats show a great variety and form unique environments in which Neoparamoeba pemaquidensis, the amoebic gill disease (AGD)-causing protozoan, may or may not survive. Tasmania is divided into two zones, one where AGD is present and one where AGD is absent, but any ecological data to rationalize this distribution is lacking. In in vitro trials N. pemaquidensis strains were exposed to different concentrations of ammonium sulphate, copper sulphate, copper sulphate and tannin, and different Neoparamoeba densities, salinities and temperatures. A trial using field water samples investigated the survival of N. pemaquidensis in waters sourced from AGD-free and AGD-positive zones, and water analysis was performed to determine any differences. Significantly decreased protozoan survival was found with exposure to increasing copper sulphate concentrations from 10 to 100,000 microM (P < 0.001), salinity of 15 per thousand (P < 0.001), low Neoparamoeba densities of 625 and 1,250 cells mL(-1) (P = 0.0005), and water sourced from Macquarie Harbour (P < 0.001). The water chemistry of this AGD-free zone showed significantly lower dissolved calcium and magnesium concentrations which may contribute to this area being AGD-free. Understanding of the ecology of N. pemaquidensis will enable better control and prevention strategies for Tasmanian salmon growers.
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Affiliation(s)
- M Douglas-Helders
- Tasmanian Aquaculture and Fisheries Institute and Aquafin CRC, School of Aquaculture, University of Tasmania, Launceston, Tasmania, Australia.
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Dyková I, Nowak BF, Crosbie PBB, Fiala I, Pecková H, Adams MB, Machácková B, Dvoráková H. Neoparamoeba branchiphila n. sp., and related species of the genus Neoparamoeba Page, 1987: morphological and molecular characterization of selected strains. JOURNAL OF FISH DISEASES 2005; 28:49-64. [PMID: 15660793 DOI: 10.1111/j.1365-2761.2004.00600.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A total of 18 Neoparamoeba strains were characterized both morphologically and using the SSU rRNA gene sequences as molecular markers. Nine were isolated from gills of farmed Atlantic salmon, Salmo salar L., six from sediments sampled in areas of sea-cage farms and three from net material of sea-cages. The newly obtained sequences extended substantially the dataset of Neoparamoeba strains available for phylogenetic analyses, which were used to infer taxonomic relatedness among 32 strains morphologically assigned to this genus. In addition to the N. pemaquidensis and N. aestuarina clades, phylogenetic analyses clearly distinguished a third clade with sequences from six strains. Members of this clade are characterized as representatives of a new species, N. branchiphila n. sp. The diagnostic primers for the identification of this species are introduced.
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Affiliation(s)
- I Dyková
- Institute of Parasitology, Academy of Sciences of the Czech Republic, Ceské Budejovice, Czech Republic.
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