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An enzyme-linked immunosorbent assay using dried blood on filter paper, was developed for the detection of antibodies against the haemoflagellate Cryptobia salmositica in juvenile rainbow trout, Oncorhynchus mykiss (Walbaum). Each fish (average weight about 5g) in three experimental groups was either inoculated with 20000 attenuated live C. salmositica vaccine, or inoculated with 2000 or 20000 pathogenic parasites per fish. The vaccine was effective in protecting juvenile trout 4 weeks after vaccination and antibody litres were higher in vaccinated and challenged fish than in unvaccinated and infected ones. Specific antibodies were detected one week post-infection (w.p.i.) with the pathogen and declined to low levels at 6 w.p.i. The high-dose group (20000 per fish) had antibody litres comparable to those of the vaccinated and challenged fish. [ABSTRACT FROM AUTHOR]

Lactococcosis, caused by the Gram‐positive bacterium Lactococcus garvieae, is a major concern in rainbow trout (Oncorhynchus mykiss) farms, which are regularly affected by outbreaks especially during the summer/fall months. In these farms, unvaccinated healthy and symptomatic fish can coexist with vaccinated fish. In the present study, innate (leukogram, serum lysozyme activity, peroxidase activity, antiprotease activity, bactericidal activity, total IgM and total proteins), and specific immune parameters (serum antibodies to L. garvieae) were assessed in unvaccinated adult rainbow trout naturally exposed to the pathogen, with or without evidence of clinical signs, or subjected to vaccination. Blood was drawn from all three groups, and blood smears were prepared. Bacteria were found in the blood smears of 70% of the symptomatic fish but not in any of the asymptomatic fish. Symptomatic fish showed lower blood lymphocytes and higher thrombocytes than asymptomatic fish (p ≤.05). Serum lysozyme and bactericidal activity did not vary substantially among groups; however, serum antiprotease and peroxidase activity were significantly lower in the unvaccinated symptomatic group than in the unvaccinated and vaccinated asymptomatic groups (p ≤.05). Serum total proteins and total immunoglobulin (IgM) levels in vaccinated asymptomatic rainbow trout were significantly higher than in unvaccinated asymptomatic and symptomatic groups (p ≤.05). Similarly, vaccinated asymptomatic fish produced more specific IgM against L. garvieae than unvaccinated asymptomatic and symptomatic fish (p ≤.05). This preliminary study provides basic knowledge on the immunological relationship occurring between the rainbow trout and L. garvieae, potentially predicting health outcomes. The approach we proposed could facilitate infield diagnostics, and several non‐specific immunological markers could serve as reliable indicators of the trout's innate ability to fight infection. [ABSTRACT FROM AUTHOR]

This article focuses on the comparison of polyclonal and monoclonal antibodies for serotyping infectious pancreatic necrosis virus (IPNV) strains isolated in eastern Canada. IPNV, the aetiological agent of an important disease of salmonids, is a member of the Birnaviridae. Using polyclonal antibodies, three main serotypes have been distinguished according to their kinetics of neutralization in the presence of excess antibody by cross neutralization tests. All American strains are related to serotype I, while European isolates have been classified in serotypes II or III. Asian strains could belong to any of these three serotypes.

Mouthrot, or bacterial stomatitis, is a disease which mainly affects farmed Atlantic salmon, (Salmo salar, L.), smolts recently transferred into salt water in both British Columbia (BC), Canada, and Washington State, USA. It is a significant fish welfare issue which results in economic losses due to mortality and antibiotic treatments. The associated pathogen is Tenacibaculum maritimum, a bacterium which causes significant losses in many species of farmed fish worldwide. This bacterium has not been proven to be the causative agent of mouthrot in BC despite being isolated from affected Atlantic salmon. In this study, challenge experiments were performed to determine whether mouthrot could be induced with T. maritimum isolates collected from outbreaks in Western Canada and to attempt to develop a bath challenge model. A secondary objective was to use this model to test inactivated wholecell vaccines for T. maritimum in Atlantic salmon smolts. This study shows that T. maritimum is the causative agent of mouthrot and that the bacteria can readily transfer horizontally within the population. Although the whole-cell oil-adjuvanted vaccines produced an antibody response that was partially cross-reactive with several of the T. maritimum isolates, the vaccines did not protect the fish under the study's conditions. [ABSTRACT FROM AUTHOR]

Grouper iridovirus (GIV) belongs to the Ranavirus genus and is one of the most important viral pathogens in grouper, particularly at the fry and fingerling stages. In this study, we identified and characterized the GIV-2L gene, which encodes a protein of unknown function. GIV-2L is 1242 bp in length, with a predicted protein mass of 46.2 kDa. It displayed significant identity only with members of the Ranavirus and Iridovirus genera. We produced mouse monoclonal antibodies against the GIV-2L protein by immunizing mice with GIV-2L-His-tag recombinant protein. By inhibiting de novo protein and DNA synthesis in GIV-infected cells, we showed that GIV-2L was a late gene during the viral replication. Finally, immunofluorescence microscopy revealed that GIV-2L protein accumulated in both the nucleus and cytoplasm of infected cells. These results offer important insights into the pathogenesis of GIV. [ABSTRACT FROM AUTHOR]

The mechanisms through which brown-marbled grouper accomplishes resistance to infection, particularly against Vibrios, are not yet fully understood. In this study, brown-marbled grouper fingerlings were experimentally infected with Vibrio parahaemolyticus, to identify disease resistance grouper, and the serum proteome profiles were compared between resistant and susceptible candidates, via two-dimensional gel electrophoresis (2- DE). The results showed that putative parvalbumin beta-2 subunit I, alpha-2-macroglobulin, nattectin and immunoglobulin light chain proteins were among proteins that significantly overexpressed in the resistant fish as compared to the susceptible group of fish, whereas apolipoprotein E and immunoglobulin light chain proteins were observed to be differentially overexpressed in the susceptible fish. Further analysis by peptide sequencing revealed that the immunoglobulin light chain proteins identified in the resistant and susceptible groups differed in amino acid composition. Taken together, the results demonstrated for the first time that putative parvalbumin beta-2 subunit I, alpha-2-macroglobulin, nattectin and immunoglobulin light chain are among important proteins participating to effect disease resistance mechanism in fish and were overexpressed to function collectively to resist V. parahaemolyticus infection. Most of these molecules are mediators of immune response. [ABSTRACT FROM AUTHOR]

KHV ORF25 fragments were cloned from Koi Herpes Virus- CJ ( KHV-CJ) strains isolated in our laboratory. The amplified products were inserted into the eukaryotic expression vector p IRES-neo, forming recombinant plasmid p IRES- ORF25. The recombinant plasmid pIRES- ORF25 at 1 μg per koi, 10 μg per koi and 50 μg per koi was intramuscularly injected into healthy kois, respectively. The results showed that the recombinant p IRES- ORF25 could induce the production of specific antibodies in koi determined by indirect ELISA. The differences of immune effect between three doses were not significant ( P > 0.05), but all of them could induce the production of neutralizing antibodies. The immune challenge test showed that the mortality of koi injected with PBS, blank p IRES-neo vector and nothing was 90%, 92.5% and 85% at 25 days. While the mortalities of koi injected with eukaryotic expression plasmid pIRES- ORF25 were 20%, 17.5% and 12.5%. Differences in comparison with the control group were highly significant ( P < 0.01). Histopathological staining revealed that the tissues of the immunized koi did not change apparently. In conclusion, the DNA vaccine pIRES- ORF25 construct could well protect koi against KHV and had the potential to be applied in practice. [ABSTRACT FROM AUTHOR]

Red-mark syndrome (RMS), a disease seen mostly in rainbow trout, Oncorhynchus mykiss, is of unknown aetiology. The research presented here indicates the presence of an intracellular bacterium in RMS-affected fish. A positive reaction was observed using immunohistochemistry (IHC) with skin lesions, liver, kidney and spleen of affected fish sampled from several locations within the United Kingdom using two different polyclonal antisera raised against Piscirickettsia salmonis. The same reaction was also seen with a number of different anti- P. salmonis monoclonal antibodies (MAbs). A disease with similar clinical signs to RMS, referred to as strawberry disease (SD), has been reported in the USA. A Rickettsia-like organism (RLO) has recently been associated with SD based on analysis of 16S rDNA sequences. Using the same panel of anti- P. salmonis antibodies used to screen the RMS samples, similar staining was obtained in tissue of SD-affected fish by IHC. A polymerase chain reaction (PCR) using RLO-specific primers was also performed on RMS-affected fish from the United Kingdom, and the samples were positive for the RLO 16S rRNA sequence. These findings suggest that the same aetiological agent may be responsible for RMS in the United Kingdom and SD in the USA. [ABSTRACT FROM AUTHOR]

Use of antibiotics for the control of bacterial diseases in shrimp culture has caused several adverse impacts to the industry. This has resulted in the search for alternative environment friendly approaches to overcome bacterial infections. This study was conducted to investigate the use of beneficial bacteria as an alternative to antibiotics. Ten pathogenic bacterial species isolated from shrimp, Penaeus monodon, and Artemia cysts were tested for susceptibility to indigenous marine Bacillus subtilis AB65, Bacillus pumilus AB58, Bacillus licheniformis AB69 and compared with oxytetracycline, chloramphenicol, gentamicin and bacitracin, which are common antibiotics used in Asian aquaculture. The Bacillus spp. were isolated from the local marine environment for bioremediation use in shrimp hatcheries and were proven to reduce total ammonium nitrogen. The pathogenic bacterial isolates were 90% susceptible to B. subtilis AB65, 70% susceptible to B. pumilus AB58 and B. licheniformis AB69 and 100% susceptible to oxytetracycline, chloramphenicol and gentamicin but only 40% to bacitracin. Two representative isolates of the vibrio group, Vibrio alginolyticus VaM11 and Vibrio parahaemolyticus VpM1, when tested for competitive exclusion by a common broth method using the marine Bacillus spp., showed decreased viable counts from 108 to 102 cfu mL−1. The results suggest that the action of the marine bacteria appears to be significant in protecting the host shrimp against pathogenic bacteria. In addition to the alternative use of antibiotics, the selected marine bacteria had additional bioremediation properties of reducing ammonia. [ABSTRACT FROM AUTHOR]

Adult Japanese eels, Anguilla japonica Temminck & Schlegel, (200–250 g, 45–55 cm) were immunized by intramuscular injection with goat IgG. After 5 weeks, eel immunoglobulin (Ig) was purified using affinity chromatography. The purified eel Ig was used to immunize rabbits to produce anti-eel Ig antibody. The highest antibody ELISA value in eels was reached 3 weeks after initial immunization with goat IgG, and then gradually decreased. The antibody could still be detected at 140 days post-immunization. The optimal temperature for antibody production was 30°G. Freund's complete adjuvant and secondary immunization both increased antibody production in eels. [ABSTRACT FROM AUTHOR]

A Sphaerospora sp. (Myxosporea) infection (presumably S. truttae) was identified on a trout farm in northeastern Italy. Parasites were detected in kidneys from infected brown trout, Salmo trutta L., over a 2-year period. Extrasporogonic, sporogonic stages and mature spores were simultaneously detected in the same fish. Traditional diagnostic methods for Sphaerospora spp. rely on the detection of the myxosporean developmental stages in Giemsa-stained kidney smears or haematoxylin-eosin stained tissue sections. A histochemical method was employed where 10 biotinylated lectins (Con-A, DBA, SBA, GS4, PHAP, LEA, PWM, RCA1, WGA and UEA-I) and the avidin-biotin-peroxidase complex (ABC) were used on Sphaerospora-infected brown trout renal tissues and kidney imprints. Five monoclonal antibodies against PKX (Mab12, MabA3, MabC5, MabD4 and MabB4) were also tested. A lectin glycoconjugate binding pattern for Sphaerospora spp. is presented. This staining method shows that SBA lectin (Glycine max agglutinin) is a useful tool for the detection of the Sphaerospora spp. Only MabB4 bound some of the most mature sporogonic stages. In contrast Mabs12, A3, C5 and D4, and GS-I lectin (Griffonia simplicifolia agglutinin) did not stain any of the Sphaerospora spp. stages, but did bind very specifically to the sporogonic and extrasporogonic stages of PKX, the causative agent of proliferative kidney disease (PKD). [ABSTRACT FROM AUTHOR]

A humoral response of Japanese eel, Anguilla Japonica Temminck & Schlegel, to the microsporean Pleistophora anguillarum Hoshina was demonstrated using immunoblotting and an enzyme-linked immunosorbent assay (ELISA). Japanese eel immunoglobulin was purified by affinity chromatography. The immunoglobulin was composed of 25-kDa light chains and 72-kDa heavy chains. The ELISA values of P. anguillarum antibodies in naturally infected fish sera were significantly higher than those of clinically healthy fish. Spore proteins from the microsporean were separated by electrophoresis and subjected to analysis by Western blot. Sera from naturally infected fish showed different reaction patterns to the spore proteins. While the sera randomly selected from naturally infected eels all showed a significant positive reaction to P anguillarum antigens, the mucus from only three out of the nine infected eels reacted positively in the ELISA test. Subsequent analyses indicated that there was no significant difference in the amount of mucus immunoglobulin among the tested eels. Therefore, the generally lower ELISA values of mucosal anti-P anguillarum antibodies from the infected eels tested were evidently not caused by a lack of immunoglobulin per se, but seem to be the result of a lack of anti-P anguillarum antibodies in the mucus and/or a lower affinity in the anti-P anguillarum antibodies that were present. [ABSTRACT FROM AUTHOR]

The results of comparative immunohisto-chemical staining studies with two lectin probes, GS-I and SBA, and five monoclonal antibodies raised against the PKX myxosporean are presented. In order to investigate the postulated link between PKX and Sphaerospora spp., the lectins and monoclonal antibodies were tested against PKX, Sphaerospora renicola, Sphaerospora oncorhynchi, Sphaerospora elegans, Sphaerospora truttae and Sphaero-spora sp. from Atlantic salmon, Salmo salar L., and Ceratomyxa shasta. SBA appears a useful tool for the diagnosis of all Sphaerospora spp. infections and was also positive for C. shasta. GS-I and monoclonal antibodies (12, C5, D4 and A3) appear to be specific for both the extrasporogonic and sporogonic stages of PKX. Although MabB4 was raised to PKX, it appears to stain some of the sporogonic stages of Sphaerospora spp. but not C. shasta. The results of the lectin and monoclonal staining of PKX and Sphaerospora oncorhynchi indicated that further work was required to prove or disprove the hypothesis that PKX and S. oncorhynchi are the same organism. [ABSTRACT FROM AUTHOR]

A panel of 15 monoclonal antibodies (MAbs) were raised against infectious pancreatic necrosis virus (IPNV) associated with lake trout, Salvelinus namaycush (Walbaum), (LT-IPNV) in Cornwall Lake, Alberta, Canada, for LT-IPNV epitope analysis and comparison with other Canadian IPNV isolates. All the MAbs reacted with IPNV VP2 polypeptide in Western blot and 10 MAbs were neutralizing. Both conformation and sequence dependent epitopes were found to be present on the IPNV VP2 protein. The antibodies recognized different epitopes on VP2 protein in reciprocal blocking ELISA. Twelve MAbs recognized common epitopes present LT-IPNV and IPNV from Arctic char. Salvelinus alpinus (L.), (AC-IPNV) in binding and neutralization assays. Three MAbs reacted only with LT-IPNV, indicating that it has distinct epitopes, and thus, clearly differentiating it from AC-IPNV isolated from the adjacent Northwest Territories. Only Two MAbs bound to Ja and BC1-IPNV isolates and none of the MAbs neutralized these two IPNV isolates. LT-IPNV was found to be a distinct isolate, more closely related to AC-IPNV and Canada-2 than to Ja-IPNV from Alberta or other isolates in Canada. Additionally, the panel of MAbs could differentiate all the proposed Canadian IPNV serotypes, namely C1, C2, C3 and Ja. [ABSTRACT FROM AUTHOR]

Alpha foetoprotein (AFP)-like immunoreactivity was detected by double immunodiffusion in the sera of adult rainbow trout, Oncorhynchus mykiss (Walbaum), histologically confirmed hepatocellular carcinoma experimentally induced in microinjection of embryos with aflatoxin B1 (AFB1). Partial characterization indicated that this AFP-like immunoreactivity gave immunologic cross-reaction of partial identity with human AFP, had alpha1 electrophoretic mobility, and an estimated molecular weight of 72 kDa. Elevate serum AFP-like immunoreactivity levels were also measured by RIA in seven out of eight adult rainbow trout with hepatocellular carcinoma, and in three out of 17 AFB1-exposed trout without demonstrable gross or microscopic evidence for hepatocellular neoplasms. No serum AFP-like immunoreactivity was detected or measured in normal healthy age-matched DMSO-control rainbow trout. These data are consistent with the following with the following conclusions: (1) AFP-like immunoreactivity detected and measured in the sera of rainbow trout with hepatocellular carcinoma is an analogue to human AFP; and (2) the elevated serum AFP levels measured in adult rainbow trout with hepatocellular carcinoma resemble those found in human with this same malignancy. These data further suggest that serum AFP measurements might be useful to confirm the appearance of hepatocellular carcinoma in experimental fish carcinogen-assay systems, and to detect hepatocellular neoplasia in high-risk wild fish populations exposed to carcinogenic pollutans. [ABSTRACT FROM AUTHOR]

Seven isolates of Edwardsiella ictaluri were evaluated for channel catfish red blood cell and neutrophil agglutination properties and reactivity with lectins and carbohydrates. All isolates were agglutinated by lectin derived from Ricinus communis and the intensity of the agglutination reaction could be lessened or abrogated by premixing the lectin derived from Ricinus communis with β-D-galactose or α-L-fucose. Edwardsiella ictaluri isolates also sedimented much more rapidly when mixed with lectin derived from Ricinus communis than when mixed with other lectins. Premixing Ricinus communis with β-D-galactose had the greatest effect on slowing the rate of sedimentation. Two out of the seven E. ictaluri isolates were capable of agglutinating channel catfish red blood cells and anterior kidney neutrophils, and this agglutination could be prevented by the addition of β-D-mannose. Likewise, the per cent phagocytosis of E. ictaluri isolate 1389 (the most intense neutrophil agglutinator) could be dramatically reduced by the inclusion of mannose in the assay mixture. Anterior kidney leucocytes and hepatocytes primarily reacted with lectins derived from Canavalia ensiformis, Ricinus communis and Triticum vulgaris. The presence on channel catfish cells of carbohydrate-lectin receptors similar in function to those found on mammalian cells and the reaction of E. ictaluri with specific lectins suggest that bacterial clearance and lectinophagocytosis may occur in a similar manner in catfish to that in mammals. [ABSTRACT FROM AUTHOR]

Two monoclonal antibody probes were produced against PK'X' cells. The parasites were partially purified by filtration and centrifugation of kidney tissue from rainbow trout with proliferative kidney disease and used as antigen for immunization of mice. The resulting monoclonal antibodies reacted with PK'X' cell antigens in enzyme-linked immunosorbent assay and immunohistochemistry tests. One antibody (Mab 12) appeared to be specific for PK'X' in kidney tissue, while the other (Mab 18) cross-reacted with host cell antigens in the kidney tubules. These probes are invaluable tools for the investigation of parasite surface antigens and life cycle studies. [ABSTRACT FROM AUTHOR]

The attachment of Vibrio pathogens to cells of rainbow trout, Oncorhynchus mykiss (Walbaum), was studied by use of species-specific monoclonal antibodies and indirect FJTC- immunofluorescence microscopy. Vibrio anguillarum, V. ordalli and V. paraliaemolyticus attached to cultured cells of rainbow trout gonads, various tissues of cryostat sections of whole fish, and smears of gills, intestine, buccal mucosa and skin. The attachment was inhibited by prior incubation of bacteria with monoclonal antibodies at titres of 1:32, or less. Other Vibrio pathogens used in this study did not attach to any trout cells. The research provides approaches to study the mechanisms of bacterial attachment in the onset of Vibrio infections. [ABSTRACT FROM AUTHOR]

The predominant cell surface protein (A-protein) of Aeromonas salmonicida has been purified by a method utilizing a glycine/hydroehloride extraction from whole cells and HPLC/ion exchanger (DEAE) columns. This procedure yielded two LPS-free molecules (a 40- and a 50-kDa form) both shown to contain A-protein determinants. The former appears to be a digest product of the latter, as a serine protease produced by A. salmonicida was shown to process the 50-kDa form into a 40-kDa molecule in vitro. The A-layer protein was shown to contain one isoform, although multiple isoelectric forms appeared as preparative artifacts, probably due to deamidation. The A-layer protein and LPS are the most significant surface antigens recognized by the Atlantic salmon B-lymphocytes or antibodies. Immunological studies of LPS-free and LPS-containing A-protein preparations were undertaken to test whether the two components behave like antigenic competitors or whether the LPS moiety could adjuvant the antibody response against the A-protein. The latter was shown to be the case. [ABSTRACT FROM AUTHOR]

A library of monoclonal antibodies has been developed for use in rapid diagnosis of Vibrio infections. It covers the Vibrio species that are regarded as the major fish and shelfish pathogens, many of which are also human pathogens. Blind tests confirm the accuracy of the monoclonals as a diagnostic test. Conjugation of enzyme label onto the monoclonals is providing rapid identification of Vibrio species by use of direct, rather than indirect, immunological testing. [ABSTRACT FROM AUTHOR]

Extracellular product (ECP) antigens of Aeromonas salmonicida were modified in an attempt to improve on the protection level achieved by their use in vaccination. The antigens were tested in an antigen-induced proliferation assay, for the ability to induce antibodies as measured by dot blot assay and as vaccines in vaccination/challenge trails. Modifications tested included particularization on to polystyrene beads, coating on to sheep red blood cells, mixing with BCG vaccine as adjuvant, and attachment to the T-independent carrier Ficoll. The only modification that resulted in increased protection levels was the particularization on to polystyrene beads. [ABSTRACT FROM AUTHOR]

Vibrio anguillarum isolated from diseased cod, Gadus morhua L., were serotyped by use of a panel of monoclonal antibodies. Four serotypes could be distinguished, having different lipopolysaccharide determinants. These phenotypic differences were also reflected in the genetic map, as revealed by fingerprinting of bacterial DNA. Antisera were raised in cod after immunization with the V. anguillarum serotypes, and Western blot techniques demonstrated production of specific antibodies mainly to LPS-antigens. The immune system in cod discriminates to a certain degree between the four serotypes as shown by crossreactions of the immune sera in ELISA. Moreover, it was also shown that natural antibodies to bacterial antigens are present in non-immune sera, but these specificities are non-LPS in nature. As a consequence of the heterogeneity of the V. anguillarum strains, vaccination experiments were performed under laboratory conditions to compare the effectiveness of bacterins based on either single vaccines or polyvaccines. The results from these experiments were promising since challenge with one strain demonstrated 100% protection both in fish vaccinated with the homologous serotype as well as a mixture of all the four serotypes. [ABSTRACT FROM AUTHOR]

Immunohistochcmical examination showed that trypsin was present in mucussecreting cell layers of Atlantic salmon, such as surface epithelial cells of gills and intestine, and epidermal cells of dorsal skin. Trypsin in tissue slices was identified by an immunohistochemieai technique which used affinity purified immunoglobulins from rabbit antisera against purified salmon pancreatic trypsin as primary antibodies. Most of the positively stained cells appeared to be granulated and secretory. The authors hypothesize that trypsin in mucussecreting cell layers is a part of the non-specific immune defence of the fish. [ABSTRACT FROM AUTHOR]

Atlantic salmon, Salmo salar L., responded to intraperitoneal injection of formalin killed Vibrio salmonicida or live infectious pancreatic necrosis virus (IPNV) by producing specific antibodies. The antibody titre varied significantly within the group tested. Western blot analysis demonstrated that high-titre antisera recognized two major bacterial antigens with molecular weights of 12-15kD and 22-27kD. In addition, a few narrow bands with higher molecular weights were observed. An antiserum raised against IPNV recognised two major antigens corresponding to the structural proteins of the virus. ELISA and Western blot analysis showed that the immune serum raised against Vibrio salmonicida reacted slightly with Vibrio anguillarum, whereas no reaction to Yersinia ruckeri or Aeromonas salmonicida was detected. Indirect ELISA and an EUSA competition assay revealed that the immune serum raised against the Nl serotype was specific for this serotype of IPNV. The results demonstrate that Atlantic salmon has a humoral immune system capable of producing antibodies which discriminate between related bacterial antigens and between different serotypes of a virus. [ABSTRACT FROM AUTHOR]

The tissue response of Salmo gairdneri Richardson, against the myxosporean parasite. Ceratomyxa shasta (Noble). was investigated using histological techniques, scanning electron microscopy and immunological methods. The progress of infection in C. shastae susceptible and resistant steelhead and rainbow trout was examined by standard histological techniques and by indirect fluorescent antibody methods using monoclonal antibodies directed against C shasta antigens. Trophozoite stages were first observed in the posterior intestine and there was indication that resistance was due to the inability of the parasite to penetrate this tissue rather than to an inflammatory response. Examination of a severely infected intestine by scanning electron microscopy showed extensive destruction of the mucosal folds of the posterior intestine - Western blotting and indirect fluorescent antibody techniques were used to investigate the immunological component of the host response. No antibodies specific for C. shasta were detected by either method. [ABSTRACT FROM AUTHOR]

Monoctonal antibodies specific to Bonamia ostreac (Ascetospora), the intrahaemocytic parasite of the flat oyster. Ostrea edulis L., were used in an indirect fluorescent antibody assay, firstly to define the subcellular location of their epitopes and, secondly. as a means of diagnosis of the disease. [ABSTRACT FROM AUTHOR]

There are two basic antigenic components in Cryptobia that are responsible for the anaemia in infected rainbow trout. A 'lytic component', which is dosage-dependent, causes lysis of red blood cells independent of antibody or complement. The second, an 'immune-complex-forming components', attaches to red blood cells, forms immune complexes with specific antibody and activates complement resulting in haemolysis. These two antigenic components, from both live and lysed Cryptobia, were present in the serum of infected fish. When sonicated antigen or heat-inactivated antiserum (from infected fish) was incubated with red cells from uninfected fish, a portion of the red cells was lysed and a positive Coombs' reaction was observed with the remaining intact red cells, The positive Coombs' reaction was due to immune complexes adsorbed onto the red cells and these lysed when incubated with complement. Antibody by itself did not adsorb onto the red cells. From the fourth week post-infection, a positive Coombs' reaction was observed in all infected fish and haemolysis occurred with complement. The authors suggest that, in infected fish, one or more components of the complement cascade is depleted continually during infection and that the anaemia is due to the lytic action of the antigen and immune complex formation on red cells. These lead to intra-vascular haemolysis as well as erythrophagocytosis. In general, the mechanism of anaemia in cryptobiosis appears similar to that in African trypanosomiasis. [ABSTRACT FROM AUTHOR]

This article describes the production of monoclonal antibodies against Renibacterium salmoninarum. The study aimed to serologically compare selected isolates of R. salmoninarum using monoclonal antibodies and to produce a monoclonal antibody which could be used for immunodiagnosis. Monoclonal antibody technology makes it possible to analyse specific and cross-reacting antigens among strains of a single bacterial species. Monoclonal antibodies produced against three isolates of R. salmoninarum were analysed for their cross-reactivity among different strains using an indirect ELISA (enzyme-linked immunosorbent assay) and immunofluorescent assay (FA). This work represents the first report of monoclonal antibodies in the serological analysis of R. salmoninarum.

Injected vaccines consisting of formalin-killed cells and extracellular antigens prepared from a virulent and an avirulent strain of Aeromonas salmonicida were tested for their efficacy in protecting juvenile coho salmon, Oncorhynchus Kisutch (Walbaum), against experimental frurnculosis following active and passive immunization. Sera used in the passive immunization experiments were raised in subadult coho salmon and in rabbits. Results indicated that the avirulent strain was inferior to the virulent strain in its immunogenicity for coho salmon. Thus, even though avirulent cells possessed at least one immunogen-in immunogen that was shown in passive immunization experiments to be well recognized by rabbits-the immunogen was only inefficiently recognized by the salmon, since they received only feeble and inconsistent protection when vaccinated with avirulent cells. Further, extracellular antigens of the avirulent strain were not protective for coho salmon even though they clicited the production of anti-A. salmonicida agglutinins. In contrast, the killed cells and extracellular antigens of the virulent strain were both immunogenic in coho salmon. By passively immunizing coho salmon with rabbit sera raised against the virulent and the avirulent strain, it was shown, using non-absorbed and cross-absorbed sera, that the virulent strain produced at least two immunogens, only one of which was shared in common with the avirulent stain. The extra immunogen possessd by the virulent stain is presumably responsible for its superior immunogenicity in coho salmon; the immunogen had the properties of a protein and is believed to be the A-protein. [ABSTRACT FROM AUTHOR]

Morbidity of intensively cultured red abalone, Haliotis rufescens, as well as experimentally stressed (elevated temperature and hyper-oxygenation) abalone, was studied using clinical, histological, immunofluorescent and bacteriological techniques. Histological study showed a typical pattern of bacterial infection from all groups studied, characterized by epithelial exfoliation or rupture and systemic growth of the bacteria along vascular sinuses and along neural sheaths. Peripheral neurons degenerated rapidly and a responsive host cellular infiltrate did not appear to effectively retard the advancement of the infection. Nine bacterial isolates from the culture system water or sick animals were characterized biochemically. All were Gram-negative, facultatively anaerobic, non-aerogenic, oxidase-positive rods with single polar flagella and thus appeared related to the Vibrio group. Further characterization showed that most isolates did not correspond to specifically characterized vibrios. Antiserum prepared to the isolates contained antibody both to common group antigens (from all nine strains) and to strain-specific antigens. Selection of antiserum and subsequent absorption permitted the use of the antiserum for specific recognition of each isolate. Immunofluorescent studies clearly demonstrated that antiserum to an isolate corresponding to Vibrio alginolyticus was the predominant antiserum producing positive staining of infecting bacteria in the typical lesions in abalone tissues. The pattern of positive staining corresponded to histopathological observations of the disease. The disease can be managed in husbandry systems by both limiting the number of potentially pathogenic bacteria and by limiting the exposure of the animals to physicochemical stresses. [ABSTRACT FROM AUTHOR]

Both under-yearling and post-yearling Atlantic salmon parr produced high agglutinating antibody titres in response to a single intraperitoneal injection of killed bacterial kidney disease (BKD) cells emulsified in Freund's complete adjuvant (FCA). Low or no response was observed in animals injected with BKD cells in saline or in animals vaccinated by hyperosmotic immersion. Immunological duration was insufficient in fish vaccinated as under-yearling parr to provide protective immunity 2 years later when the fish had become smolts. Atlantic salmon post-year1ing parr injected with BKD cells in FCA demonstrated a reduced prevalence of EKD lesions compared to control animals when both were observed as smolts 1 year after vaccination. [ABSTRACT FROM AUTHOR]