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At least 19 recordsLinked to original sources
USGS2016

Transforming growth factor-β1 expression in endangered age-0 shortnose suckers ( Chasmistes brevirostris ) from Upper Klamath Lake, OR relative to histopathology, meristic, spatial, and temporal data

During July – September of 2008, 2009, and 2010 endangered age-0 juvenile shortnose suckers were sampled from Upper Klamath Lake, OR in a health evaluation that included the measurement of transforming growth factor – beta (TGF-β) expression in spleen in combination with a histopathology assessment. This analysis was performed to determine if the expression of this immuno-regulator could be used as a component of a larger health evaluation intended to identify potential risk-factors that may help to explain why very few of these fish survive to age-1. Potential associations between TGF-β1 expression, histopathological findings, meristic data as well as temporal and spatial data were evaluated using analysis-of-variance. In this analysis, the absence or presence of opercula deformity and hepatic cell necrosis were identified as significant factors in accounting for the variance in TGF-β1 expression observed in age-0 shortnose suckers (n = 122, squared multiple R = 0.989). Location of sample collection and the absence or presence of anchor worms ( Lernaea spp.) were identified as significant cofactors. The actual mechanisms involved with these relationships have yet to be determined. The strength, however, of our findings support the concept of using TGF-β1 expression as part of a broader fish health assessment and suggests the potential for using additional immunologic measures in future studies. Specifically, our results indicate that the measure of TGF-β1 expression in age-0 shortnose sucker health assessments can facilitate the process of identifying disease risks that are associated with the documented lack of recruitment into the adult population.

Oregon↗
USGS2004

Quantitative expression profiling of immune response genes in rainbow trout following infectious haematopoietic necrosis virus (IHNV) infection or DNA vaccination

Infectious haematopoietic necrosis virus (IHNV) is a well-studied virus of salmonid fishes. A highly efficacious DNA vaccine has been developed against this virus and studies have demonstrated that this vaccine induces both an early and transient non-specific anti-viral phase as well as long-term specific protection. The mechanisms of the early anti-viral phase are not known, but previous studies noted changes in Mx gene expression, suggesting a role for type I interferon. This study used quantitative real-time reverse transcriptase PCR methodology to compare expression changes over time of a number of cytokine or cytokine-related genes in the spleen of rainbow trout following injection with poly I:C, live IHNV, the IHNV DNA vaccine or a control plasmid encoding the non-antigenic luciferase gene. The target genes included Mx-1, viral haemorrhagic septicaemia virus induced gene 8 (Vig-8), TNF-α1, TNF-α2, IL-1β1, IL-8, TGF-β1 and Hsp70. Poly I:C stimulation induced several genes but the strongest and significant response was observed in the Mx-1 and Vig-8 genes. The live IHN virus induced a significant response in all genes examined except TGF-β1. The control plasmid construct and the IHNV DNA vaccine marginally induced a number of genes, but the main difference between these two groups was a statistically significant induction of the Mx-1 and Vig-8 genes by the IHNV vaccine only. The gene expression profiles elicited by the live virus and the IHNV DNA vaccine differed in a number of aspects but this study confirms the clear role for a type I interferon-like response in early anti-viral defence.

Fish & Shellfish Immunology↗
USGS2014

In vitro immune functions in thiamine-replete and -depleted lake trout ( Salvelinus namaycush )

In this study we examined the impacts of in vivo thiamine deficiency on lake trout leukocyte function measured in vitro. When compared outside the context of individual-specific thiamine concentrations no significant differences were observed in leukocyte bactericidal activity or in concanavalin A (Con A), and phytohemagglutinin-P (PHA-P) stimulated leukocyte proliferation. Placing immune functions into context with the ratio of in vivo liver thiamine monophosphate (TMP – biologically inactive form) to thiamine pyrophosphate (TPP – biologically active form) proved to be the best indicator of thiamine depletion impacts as determined using regression modeling. These observed relationships indicated differential effects on the immune measures with bactericidal activity exhibiting an inverse relationship with TMP to TPP ratios, Con A stimulated mitogenesis exhibiting a positive relationship with TMP to TPP ratios and PHA-P stimulated mitogenesis exhibiting no significant relationships. In addition, these relationships showed considerable complexity which included the consistent observation of a thiamine-replete subgroup with characteristics similar to those seen in the leukocytes from thiamine-depleted fish. When considered together, our observations indicate that lake trout leukocytes experience cell-type specific impacts as well as an altered physiologic environment when confronted with a thiamine-limited state.

Fish & Shellfish Immunology↗
USGS2014

Channel catfish (Ictalurus punctatus) leukocytes express estrogen receptor isoforms ERα and ERβ2 and are functionally modulated by estrogens

Estrogens are recognized as modulators of immune responses in mammals and teleosts. While it is known that the effects of estrogens are mediated via leukocyte-specific estrogen receptors (ERs) in humans and mice, leucocyte-specific estrogen receptor expression and the effects of estrogens on this cell population is less explored and poorly understood in teleosts. Here in, we verify that channel catfish ( Ictalurus punctaus ) leukocytes express ERα and ERβ2. Transcripts of these isoforms were detected in tissue-associated leukocyte populations by PCR, but ERβ2 was rarely detected in PBLs. Expression of these receptors was temporally regulated in PBLs following polyclonal activation by concanavalin A, lipopolysaccharide or alloantigen based on evaluation by quantitative and end-point PCR. Examination of long-term leukocyte cell lines demonstrated that these receptors are differentially expressed depending on leukocyte lineage and phenotype. Expression of ERs was also temporally dynamic in some leukocyte lineages and may reflect stage of cell maturity. Estrogens affect the responsiveness of channel catfish peripheral blood leukocytes (PBLs) to mitogens in vitro . Similarly, bactericidal activity and phorbol 12-myristate 13-acetate induced respiratory burst was modulated by 17β-estradiol. These actions were blocked by the pure ER antagonist ICI 182780 indicating that response is, in part, mediated via ERα. In summary, estrogen receptors are expressed in channel catfish leukocytes and participate in the regulation of the immune response. This is the first time leukocyte lineage expression has been reported in teleost cell lines.

Fish & Shellfish Immunology↗
USGS2016

Innate and adaptive immune responses in migrating spring-run adult chinook salmon, Oncorhynchus tshawytscha

Adult Chinook salmon ( Oncorhynchus tshawytscha ) migrate from salt water to freshwater streams to spawn. Immune responses in migrating adult salmon are thought to diminish in the run up to spawning, though the exact mechanisms for diminished immune responses remain unknown. Here we examine both adaptive and innate immune responses as well as pathogen burdens in migrating adult Chinook salmon in the Upper Willamette River basin. Messenger RNA transcripts encoding antibody heavy chain molecules slightly diminish as a function of time, but are still present even after fish have successfully spawned. In contrast, the innate anti-bacterial effector proteins present in fish plasma rapidly decrease as spawning approaches. Fish also were examined for the presence and severity of eight different pathogens in different organs. While pathogen burden tended to increase during the migration, no specific pathogen signature was associated with diminished immune responses. Transcript levels of the immunosuppressive cytokines IL-10 and TGF beta were measured and did not change during the migration. These results suggest that loss of immune functions in adult migrating salmon are not due to pathogen infection or cytokine-mediated immune suppression, but is rather part of the life history of Chinook salmon likely induced by diminished energy reserves or hormonal changes which accompany spawning.

Oregon↗
USGS2019

In vitro immune function in laboratory-reared age-0 smallmouth bass (Micropterus dolomieu) relative to diet

Smallmouth bass ( Micropterus dolomieu ) are used as an indicator species in environmental monitoring and assessment studies. However, laboratory-based studies for methods development and effector assessment are limited for this species. Nutrition, a known modulator of teleost physiological responses including immune function, is a critical knowledge-gap sometimes overlooked in the design of laboratory studies. We report the results from a study evaluating a commercially available artificial pelleted diet for bass and live feed (fathead minnows). Following a six-month diet-acclimation period, age-0 smallmouth bass were assessed using morphometric measures, histologic and immune-function end points using conventional methods, miniaturized cell isolation and assay methods as well as imaging flow cytometry. Fish on the two diets did not significantly differ in length, weight, or condition factor, indicating that growth was similar in the two groups. Histologic examination revealed relatively higher levels of macrophage aggregates and accumulation of ceroid/lipofuscin in the spleen as well as hepatocyte changes in the pellet-fed group. Leukocytes from the pellet-fed group exhibited significantly elevated bactericidal activity and significantly depressed mitogen response compared to fish fed live feed. Following exposure to a known inducer of inflammatory responses, bacterial lipopolysaccharide, responses including the transition of leukocytes to an apoptotic/necrotic condition differed significantly based on diet. Histologic findings were consistent with the occurrence of diet-related oxidative stress in the pellet-fed fish. Oxidative stress can be induced by multiple factors including environmental pollutants. For a diet to be useful in laboratory-based studies, it cannot elicit response that could also be induced by experimental treatments. To do so greatly complicates the detection of experimental effects. Until an artificial diet is developed for smallmouth bass that does not produce potentially confounding conditions for laboratory-based studies, use of a live feed appears to be the best option.

Fish & Shellfish Immunology↗
USGS2021

Production and characterization of a mouse monoclonal antibody against smallmouth bass (Micropterus dolomieu) IgM

A murine monoclonal antibody (mAb, IgG2a) was produced for the detection of smallmouth bass ( Micropterus dolomieu ) immunoglobulin (IgM). The antibody is specific for IgM heavy chain and was shown to also recognize the Ig heavy chain of largemouth bass ( Micropterus salmoides ) and bluegill ( Lepomis macrochirus ) using Western Blot analysis of plasma from 9 teleost taxa. When applied to the analysis of smallmouth bass total plasma IgM using ELISA, the mAb was found to be effective when used in an inhibition kinetic assay.

Fish & Shellfish Immunology↗
USGS2001

Antibody-producting cells correlated with body weight in juvenile Chinook salmon Oncorhynchus tshawytscha acclimated to optimal and elevated temperatures

The immune response of juvenile chinook salmon ( Oncorhynchus tshawytscha ) ranging in weight from approximately 10 to 55 g was compared when the fish were acclimated to either 13 or 21° C. A haemolytic plaque assay was conducted to determine differences in the number of antibody-producing cells (APC) among fish of a similar age but different body weights. Regression analyses revealed significant increases in the number of APC with increasing body weight when fish were acclimated to either water temperature. These results emphasise the importance of standardising fish weight in immunological studies of salmonids before exploring the possible effects of acclimation temperatures.

Fish & Shellfish Immunology↗
USGS2012

Induction of anti-viral genes during acute infection with Viral hemorrhagic septicemia virus (VHSV) genogroup IVa in Pacific herring ( Clupea pallasii )

Infection with the aquatic rhabdovirus Viral hemorrhagic septicemia virus (VHSV) genogroup IVa results in high mortality in Pacific herring ( Clupea pallasii ) and is hypothesized to be a potential limiting factor for herring recovery. To investigate anti-viral immunity in the Pacific herring, four immune response genes were identified: the myxovirus resistance ( Clpa- Mx), a major histocompatibility complex IB (named Clpa- UAA.001), the inducible immunoproteosome subunit 9 ( Clpa- PSMB9) and the neutrophil chemotactic factor ( Clpa- LECT2). Reverse transcriptase quantitative PCR (RT-qPCR) assays were developed based on these gene sequences to investigate the host immune response to acute VHSV infection following both injection and immersion challenge. Virus levels were measured by both plaque assay and RT-qPCR and peaked at day 6 during the 10-day exposure period for both groups of fish. The interferon stimulated genes ( Clpa- Mx, −UAA.001, and −PSMB9) were significantly up-regulated in response to VHSV infection at both 6 and 10 days post-infection in both spleen and fin. Results from this study indicate that Pacific herring mount a robust, early antiviral response in both fin and spleen tissues. The immunological tools developed in this study will be useful for future studies to investigate antiviral immunity in Pacific herring.

Fish and Shellfish Immunology↗
USGS1991

Responses to in vitro and in vivo immunisations with Aeromonas salmonicida O antigen bacterins in rainbow trout (Oncorhynchus mykiss)

Immunological assays were developed to test for the effects of immunisation with Aeromonas salmonicida O antigen bacterin in rainbow trout ( Oncorhynchus mykiss ) in vitro and in vivo . Trout spleen sections were immunised in vitro by incubation in media containing 100, 10, and 1 μ g ml −1 of the A. salmonicida O antigen. After 10 days at 15°C, the individual sections were minced and cell suspensions assayed for the effects of the bacterin on non-specific and specific immune responses. Assays of the cell suspensions showed that the neutrophil oxidative activity, phagocytic capabilities, numbers of plaque-forming cells (PFC) and circulating antibody titres all increased in proportion to the bacterin dosage. Trout immunised in vivo with 100 μ g by injection and by 100 μ g ml −1 bath with the O antigen, showed similar responses to spleen sections immunised in vitro . The appearance of non-specific PFC against unlabelled sheep red blood cells was highest in spleens immunised in vitro and in the fish immunised by injection; non-specific PFC rarely occurred in O antigen bathed fish and in control fish. The development of these assays may enable biologists to follow the effects on the non-specific defence mechanisms and the specific immune response in cultivated fish populations after, immunisation with A. salmonicida bacterins and thus aid in the development of protective vaccination against furunculosis.

Fish and Shellfish Immunology↗
USGS1993

Enhanced immune response and protection rainbow trout to Aeromonas salmonicida bacterin following prior immersion immunostimulants

Bathing rainbow trout for 30 min in immunostimulant solutions before a 2 min bath in Aeromonas salmonicida O antigen bacterin elevated both the nonspecific defence mechanisms and the specific immune response. Levamisole, a known T lymphocyte stimulator in mammals; QAC, a quaternary ammonium compound, and ISK a short-chain polypeptide, heightened the neutrophil oxidative activity as measured by nitroblue tetrazolium assay and increased the phagocytic uptake of glutaraldehyde-fixed sheep red blood cells. The heightened activity of the specific immune response was monitored by counting numbers of plaque-forming cells, and by demonstrating elevated circulatory antibody titres. Protection levels against the virulent pathogen were also increased when the fish were challenged 14 days later. Giving an immunostimulatory bath before the antigen bath is a relatively easy method of increasing efficacy and potency of immunogens for the prevention of diseases in fishes.

Fish and Shellfish Immunology↗
USGS1996

Immune and endocrine responses of adult spring Chinook salmon during freshwater migration and sexual maturation

The immune –endocrine responses in spring chinook salmon ( Oncorhynchus tshawytscha ) were examined during their freshwater migration and final maturation. In 1990, migrating fish had high plasma cortisol titres (means 200 ng ml −1 ) and generated relatively few antibody-producing cells (APC) from peripheral blood leukocytes (PBL) (100 –200 per culture). After three weeks acclimation in constant environmental conditions, plasma cortisol was reduced and APC increased. There were no changes in number or affinity of glucocorticoid receptors. Concentrations of several sex steroids correlated with APC in females, but there were no such correlations in males. In 1993, fish in a hatchery had significantly greater cortisol concentrations in primary circulation than in secondary circulation, but sex steroid concentrations did not differ between circulations. Mean lysozyme activity in the primary and secondary circulation did not differ in June. In August, activity in the primary circulation was significantly less than that of the secondary, perhaps the result of acute stress associated with sampling. While some sex steroids correlated with lysozyme activity, the fact that in both years all endocrine and immune variables that correlated with each other also correlated with the date of sample, raises the question as to whether or not these are cause-and-effect relations.

Fish and Shellfish Immunology↗
USGS1998

Fish thymocyte viability, apoptosis and necrosis: In-vitro effects of organochlorine contaminants

The thymus is believed to be a central component of haematopoiesis and immune function in teleosts. Hence, chemically-elicited adverse effects to the thymus may result in immunomodulation and organ dysfunction. The objective of this research was to assess the levels of active (apoptotic) and passive (necrotic) cell death in untreated and organochlorine treated fish thymocytes. Lake trout ( Salvelinus namaycush ) thymocytes were challenged with Aroclor 1254 (concentration range 1·5–10·5 μg ml −1 ) and alpha, beta, gamma, delta isomers of hexachlorocyclohexane (concentration range 10–100 μ M ). The resulting maintenance or loss of viability was assessed by cytofluorometry (expression of phosphatidylserine and exclusion of propidium iodide) and confirmed with fluorescence microscopy. The results indicate that 20–60% of thymocytes in healthy fish undergo apoptosis, whereas thymocytes treated for 6–24 h with organochlorines exhibit increased levels of apoptotic cell death. This study demonstrates that given sufficient concentration, contact time and cellular receptors, organochlorines such as Aroclor 1254 and hexachloro-cyclohexanes may induce direct or indirect toxicity, altered functionality, or cell death to an organ important for fish immunocompetence.

Fish and Shellfish Immunology↗
USGS2000

Fish DNA vaccine against infectious hematopoietic necrosis virus: efficacy of various routes of immunization

The DNA vaccine, pIHNVw-G, contains the gene for the glycoprotein (G) of the rhabdovirus infectious hematopoietic necrosis virus (IHNV), a major pathogen of salmon and trout. The relative efficacy of various routes of immunisation with pIHNVw-G was evaluated using 1.8 g rainbow trout fry vaccinated via intramuscular injection, scarification of the skin, intraperitoneal injection, intrabuccal administration, cutaneous particle bombardment using a gene gun, or immersion in water containing DNA vaccine-coated beads. Twenty-seven days after vaccination neutralising antibody titres were determined, and 2 days later groups of vaccinated and control unvaccinated fish were subjected to an IHNV immersion challenge. Results of the virus challenge showed that the intramuscular injection and the gene gun immunisation induced protective immunity in fry, while intraperitoneal injection provided partial protection. Neutralising antibodies were not detected in sera of vaccinated fish regardless of the route of immunisation used, suggesting that cell mediated immunity may be at least partially responsible for the observed protection.

Fish and Shellfish Immunology↗
USGS2002

Effects of rearing temperature on immune functions in sockeye salmon (Oncorhynchus nerka)

To determine if the defences of sockeye salmon (Oncorhynchus nerka) raised in captivity are affected by the rearing temperature or their life-cycle stage, various indices of the humoral and cellular immune functions were measured in fish reared at either 8 or 12??C for their entire life-cycle. Measures of humoral immunity included the commonly used haematological parameters, as well as measurements of complement, and lysozyme activity. Cellular assays quantified the ability of macrophages from the anterior kidney to phagocytise Staphylococcus aureus cells, or the activities of certain bactericidal systems of those cells. The T-dependent antibody response to a recombinant 57 kDa protein of Renibacterium salmoninarum was used to quantify the specific immune response. Fish were sampled during the spring and fall of their second, third and fourth years, corresponding to a period that began just before smolting and ended at sexual maturation. Fish reared at 8??C tended to have a greater percentage of phagocytic kidney macrophages during the first 2 years of sampling than the fish reared at 12??C. During the last half of the study the complement activity of the fish reared at 8??C was greater than that of the 12??C fish. Conversely, a greater proportion of the blood leucocytes were lymphocytes in fish reared at 12??C compared to the fish reared at 8??C. Fish reared at 12??C also produced a greater antibody response than those reared at 8??C. Results suggested that the immune apparatus of sockeye salmon reared at 8??C relied more heavily on the non-specific immune response, while the specific immune response was used to a greater extent when the fish were reared at 12??C. Although a seasonal effect was not detected in any of the indices measured, varying effects were observed in some measurements during sexual maturation of fish in both temperature groups. At that time there were dramatic decreases in complement activity and lymphocyte numbers. This study was unique in its scope because it was the first quantitative assessment of salmon immune functions for an entire life-cycle. ?? 2002 Elsevier Science Ltd.

Fish and Shellfish Immunology↗
USGS2002

In vitro toxicity and interactions of environmental contaminants (Arochlor 1254 and mercury) and immunomodulatory agents (lipopolysaccharide and cortisol) on thymocytes from lake trout ( Salvelinus namaycush )

The immunotoxicity of chemical combinations commonly encountered by the lake trout ( Salvelinus namaycush ) immune system was the focus of this study. It was hypothesised that combinations of an environmental contaminant (mercuric chloride or Aroclor 1254) and an immunomodulatory agent (bacterial endotoxin or cortisol) might interact to produce a greater toxicity than that of the environmental contaminant alone at concentrations typically encountered in piscine blood and other tissues. Thus lake trout thymocytes were isolated and treated with mercuric chloride or Aroclor 1254 in the presence and absence of cortisol or lipopolysaccharide. Incubations were performed for 6 or 20 h at 4° C or 10° C. Lipopolysaccharide did not affect the toxicity of either contaminant. In contrast, cortisol enhanced the toxicity of both environmental contaminants. Hence, stressors that lead to increased cortisol production, but not lipopolysaccharide directly, may increase the toxicity of mercury and Aroclor 1254 to lake trout thymocytes.

Fish and Shellfish Immunology↗