-
[show abstract]
[hide abstract]
ABSTRACT: Non-enterotoxigenic type A Clostridium perfringens are associated with bovine enterotoxaemia, but the alpha toxin is not regarded as responsible for the production of typical lesions of necrotic and haemorrhagic enteritis. The purpose of this study was to investigate the putative role of the more recently described beta2 toxin. Seven hundred and fourteen non-enterotoxigenic type A C. perfringens isolated from 133 calves with lesions of enterotoxaemia and high clostridial cell counts (study population) and 386 isolated from a control population of 87 calves were tested by a colony hybridisation assay for the beta2 toxin. Two hundred and eighteen (31%) C. perfringens isolated from 83 calves (62%) of the study population and 113 (29%) C. perfringens isolated from 51 calves (59%) of the control population tested positive with the beta2 probe. Pure and mixed cultures of four C. perfringens (one alpha+beta2+, one alpha+enterotoxin+ and two alpha+) were tested in the ligated loop assay in one calf. Macroscopic haemorrhages of the intestinal wall, necrosis and haemorrhages of the intestinal content, and microscopic lesions of necrosis and polymorphonuclear and mononuclear cell infiltration of the intestinal villi were more pronounced in loops inoculated with the alpha and beta2-toxigenic C. perfringens isolate. These results suggest in vivo synergistic role of the alpha and beta2 toxins in the production of necrotic and haemorrhagic lesions of the small intestine in cases of bovine enterotoxaemia. However, isolation of beta2-toxigenic C. perfringens does not confirm the clinical diagnosis of bovine enterotoxaemia and a clostridial cell counts must still be performed.
Veterinary Microbiology 06/2002; 86(3):191-202. · 3.33 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A monoclonal antibody (mAb) directed against the equine arteritis virus (EAV) nucleocapsid (N) protein was used for indirect enzyme-linked immunosorbent assays (ELISAs) using viral antigen from different sources. The same mAb was labelled with fluorescein isothiocyanate for direct immunofluorescence tests (DIFTs). The N-specific mAb appeared to be suitable for the detection in both ELISA and DIFT of different EAV strains and field isolates from semen and tissue samples after passage in lines of RK-13, Vero and fetal equine kidney cells. The ELISA described is an easy and fast method which can be used in most cases to replace the microneutralization test to prove the EAV specificity of the cytopathic effect of cell cultures. The DIFT, however, is more sensitive than both the ELISA and the microneutralization test because EAV antigen can be detected even in cell cultures without or with very weak cytopathic effect.
Journal of Veterinary Medicine Series B 03/2001; 48(1):1-9. · 1.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In a group of 60 Belgian White Blue calves less than 8 months old still housed in barns, a bovine respiratory syncytial virus (BRSV) outbreak was revealed on the basis of a direct diagnosis (immunofluorescence and virus isolation) performed on the lungs of dead animals, and the kinetics of BRSV neutralizing antibodies. Clinical signs, macroscopical and microscopical pulmonary lesions were also compatible with a BRSV infection. This outbreak is peculiar because the 35 oldest calves (204 +/- 29 days old) had been vaccinated 3-4 months before with an inactivated BRSV vaccine and 30% of these animals had died of respiratory distress. While they experienced a mild respiratory symptomatology, no death was recorded among the 25 youngest calves (69 +/- 29 days old) which had been left unvaccinated. Another peculiarity was found at the histological level where a massive infiltration of eosinophils was demonstrated in the pulmonary tissues of the dead animals. Together these data parallel the dramatic story described 30 years ago in children previously vaccinated with a formalin-inactivated human RSV (HRSV) vaccine upon a natural HRSV challenge. This illustrates that an immunopathological phenomenon also takes place after BRSV vaccination in cattle.
Journal of Veterinary Medicine Series B 10/2000; 47(7):535-50. · 1.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A study was conducted in Southern Belgium to determine the prevalence of bovine viral diarrhoea virus (BVDV) infection in Belgian White Blue herds. Blood samples were taken from 9685 cattle, representing all the stock on 61 farms, by local veterinarians to screen for persistently infected animals and to determine their serological status against BVDV. Some of the herds (42.5%) were selected because of a prior positive diagnosis of BVDV or on the grounds of suspicion of BVD. A capture enzyme-linked immunosorbent assay (ELISA) was used to test for antigen. The prevalence of persistently infected animals was 0.75% overall and 1.46% in the 27 herds with at least one persistently infected animal. The prevalence of seropositive animals was determined with a competitive antibody ELISA and was found to be 65.5% for the animals as a whole but 53.8% for the herds without positively infected animals and 76.6% for the herds with at least one such animal. All the herds contained seropositive animals.
The Veterinary quarterly 02/1999; 21(1):28-32. · 1.47 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The alpha-toxin produced by the type strain of Clostridium perfringens (NCTC 8237) was shown to differ from the alpha-toxins produced by most strains of C. perfringens isolated from man and from calves with respect to reactivity with a neutralizing monoclonal antibody (DY2F5D11). The difference in antibody binding correlated with three differences in the deduced amino acid sequence (Ala174 to Asp174; Thr177 to Ala177; Ser335 to Pro335) of the alpha-toxins. Using octapeptides synthesized on the basis of the amino acid sequences from these regions of variability, it was shown that the Ala174 to Asp174 change had the greatest effect on reducing the binding of monoclonal antibody DY2F5D11 to the alpha-toxin. These differences did not affect the enzymic or toxic properties of the protein. However, the phospholipase C activity of the alpha-toxin produced by strain NCTC 8237 was more susceptible to inactivation by chymotrypsin. The changes in amino acid sequence did not affect the ability of a C-terminal domain vaccine, derived from the alpha-toxin of strain NCTC 8237, to induce protection against the alpha-toxin from a bovine enteric strain of C. perfringens.
Microbiology 02/1996; 142 ( Pt 1):191-8. · 3.06 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Bovine respiratory syncytial virus (BRSV) is a major cause of respiratory disease in calves. The BRSV genome encodes two major glycoproteins, G and F, which are the major targets for the host antibody response. We have expressed the F glycoprotein in insect cells (Sf9) using a recombinant baculovirus vector. A comparison of the F protein expressed in mammalian and insect cells by SDS-PAGE showed that only part of the baculovirus-produced protein was soluble and processed like the native protein. The antigenicity of the soluble form of the F protein expressed in insect cells was identical to that of the F protein expressed in mammalian cells. Immunization with the F protein expressed in insect cells induced neutralizing antibodies in mice. This antigenic preparation adjuvanted with Quil-A produced an increased neutralizing antibody titer and induced protection.
Archives of Virology 01/1996; 141(12):2313-26. · 2.11 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: From two independent fusions, fifteen MAbs directed to the F protein of the bovine respiratory syncytial virus (BRSV) were characterized by radio-immunoprecipitation assays. Competition binding assays among these MAbs identified two distinct antigenic sites (A and B) and one overlapping site (AB). All of the MAbs specific to epitopes belonging to site A neutralized the infectivity of the virus in vitro and recognized human and bovine RSV strains. Only two out of the five MAbs directed to epitopes of site B were neutralizing and three reacted with all of the RSV strains tested, suggesting that the epitopes constituting this domain present heterogeneous characteristics. In each of sites A and B, one of the neutralizing MAbs also inhibited cell fusion. The biological relevance of these domains was established by competing representative MAbs and sera from BRSV-infected calves.
Archives of Virology 02/1995; 140(6):993-1005. · 2.11 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Monoclonal antibodies have been raised against the soluble lactotransferrin binding protein purified from the cell culture supernatant of Jurkat cell line, a human T-lymphoblastic cell. All monoclonal antibodies were able to specifically bind to the membrane of Jurkat cells. One of the monoclonal antibodies, DP5B3G10, recognized both the soluble lactotransferrin-binding protein and the membrane lymphocyte lactotransferrin receptor after SDS-PAGE in presence of 2-mercaptoethanol and electrotransfer on nitrocellulose. The monoclonal antibody DP5B3G10 inhibited the binding of lactotransferrin to Jurkat cells and human peripheral activated lymphocytes. In addition, lactotransferrin inhibited the binding of the monoclonal antibody to the cell surface. These results suggest that the 95 kDa lactotransferrin-binding protein isolated from the cell culture medium corresponds to the soluble form of the 105 kDa lymphocyte lactotransferrin receptor. Corresponding proteins of 105 kDa molecular mass were identified in Jurkat and CEM T-cells and Raji B-cells. Finally, the monoclonal antibody DP5B3G10 was used to immunolocalize the lactotransferrin receptor on the Jurkat cells. Using fluorescence and electron microscopy, the receptor was localized both inside and at the cell surface. The cell membrane receptor was associated into clusters. After permeabilization of the plasma membrane, the staining was positive in the peri-membrane area. The region near the nucleus was devoid of receptor.
European Journal of Cell Biology 11/1994; 65(1):164-71. · 2.81 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Crossreacting antigens between life cycle stages of Cryptosporidium parvum (Protozoa, Apicomplexa) were detected using monoclonal antibodies (mAbs). Shared epitopes were demonstrated by immunoelectron microscopy, at the level of micronemes of the sporozoite and merozoite stages; some dense granules were also labelled but not so intensively. The parasitophorous vacuole membranes of all intracellular stages, the wall-forming bodies of macrogametes and the outer oocyst walls all shared these epitopes. The antigens that bear these epitopes were characterized using the whole oocyst and sporozoite stages as sources of antigenic material. Complex labelling patterns were observed on Western blots. However, all the mAbs used in this study recognized an antigen of more than 500 kDa. The glycoproteinic nature of this antigen was demonstrated by its sensitivity to pronase and periodate treatments. The expression of this high molecular weight immunoreactive antigen in the intracellular stages of C parvum was not investigated and remains to be found.
Veterinary Research 02/1994; 25(4):384-98. · 4.06 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Five monoclonal antibodies produced against bovine viral diarrhea virus were characterized for some of their biological activities. All of them bound to varying degrees to pestivirus strains but failed to neutralize the virus. One of the antibodies immunoprecipitated four polypeptides presumably involved in viral envelope organization.
Archives of virology. Supplementum 02/1991; 3:239-44.
-
[show abstract]
[hide abstract]
ABSTRACT: The nucleotide sequence was determined for the fusion (F) protein-coding mRNA of the bovine respiratory syncytial virus (strain RB 94) and the amino acid sequence of the F protein was deduced for comparison with the sequence of human respiratory syncytial virus subtypes A and B (RSS-2 and 18537 strains). The human and bovine RS virus F proteins (excluding the cleaved signal peptide) share 83 to 84% homology. The greatest divergence occurred within the F2 subunit in the region preceding the cleavage activation site.
Journal of General Virology 01/1991; 71 ( Pt 12):3009-14. · 3.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This paper describes an enzyme-linked immunosorbent assay (ELISA) for the diagnosis of cryptosporidiosis. A monoclonal antibody with a high affinity against an oocyst antigen was used to set up the test. The efficiency of this assay was compared with that of the flotation test; 275 calf faecal samples were examined by the two methods. There was 96% agreement between the two tests. For the 11 conflicting samples, the two tests were repeated and a modified Ziehl-Neelsen staining was performed on faecal smears. All these 11 samples contained few oocysts, but only five and six of them were shown to be positive by the ELISA and flotation tests, respectively. The degree of sensitivity of the ELISA and flotation tests is comparable; samples heavily or moderately contaminated with oocytes are detected by both methods. This ELISA is reliable and never gives rise to false positive results. Nevertheless, as with the flotation test, the occasional case containing very few oocysts will not always be detected by this test. If necessary, very accurate diagnosis can be made by a staining technique or by a direct immunofluorescent assay. In veterinary medicine, the ELISA seems to be a method of choice; it appears to be a fast and reliable technique which could be used as a routine test for the detection of Cryptosporidium oocysts. Nevertheless the degree of sensitivity must always be borne in mind. There is no need for a microscopic examination, which is an additional advantage.
Veterinary Parasitology 09/1990; 37(1):1-8. · 2.58 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The clinical efficacy of a preparation based on the lactoperoxidase system (LP-s) and lactoferrin (LF) was tested in calves experimentally infected with E coli K99+, Ent+. Mortality, occurrence and duration of diarrhoea were significantly lower (P less than 0.05) and general clinical status significantly better (P less than 0.05) in infected calves treated with LP-s and LF preparation than in infected but non-treated calves. Results suggest that LP-s and lactoferrin are effective in the treatment of enteric colibacillosis in calves.
Annales de recherches vétérinaires. Annals of veterinary research 02/1990; 21(2):143-52.
-
[show abstract]
[hide abstract]
ABSTRACT: Monoclonal antibodies have been produced against the 81/36F strain of rotavirus. One of them, was chosen as diagnostic reagent: it showed high ELISA reactivity with all the bovine, human and porcine rotavirus strains tested and reacted with VP6, structural protein product known to support the common rotavirus antigen. A sandwich ELISA procedure using the chosen monoclonal as "capture and detecting" antibody was performed to detect rotavirus in faecal samples from experimentally inoculated newborn calves: it always gave a negative response with meconium and a positive response for the stool specimens which rotavirus have been isolated. This assay was compared with Enzygnost and Slidex Rota Kit tests and with a non-commercial sandwich ELISA test using polyclonal antibodies: it showed more sensitivity than the agglutination test and was as sensitive as the other two tests to detect rotavirus in routine diagnostic material. The test evaluated showed no equivocal results.
Comparative Immunology Microbiology and Infectious Diseases 02/1989; 12(4):95-104. · 2.34 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Monoclonal antibodies (MoAbs) reacting with bovine leukocyte membrane antigens have been prepared by fusion of mouse myeloma cells (SP2/0.Ag.14) and spleen cells of mice immunized with various cell types. Three of these MoAbs detected membrane components showing the typical structure of class I MHC molecules; indeed, immunoprecipitation studies revealed that these components were proteins composed of two subunits of 44,000 and 12,000 daltons apparent molecular weight. The density of these antigens in the cells of various leukocyte lineages was determined by solid phase radioimmunoassay, immunogold staining and cytofluorometry. Their expression seemed similar to that of class I molecules in other species, namely heavy on the mononuclear blood cells and weaker on the neutrophils and platelets. The eosinophils appeared more positive than the neutrophils, while the erythrocytes were negative. Cross-inhibition and sequential immunoprecipitation experiments demonstrated that these MoAbs recognised different epitopes either on a single molecule or on cross-reacting molecules. One antibody appeared to be raised against the monomorphic bovine beta-2-microglobulin, while the two other antibodies detected the heavy chain of polymorphic class I-like products. The authors propose that the BoLA class I polymorphism should be studied by determination of the fixation ratio of the monomorphic anti-beta 2M versus the polymorphic anticlass I antibodies amongst the animals.
Veterinary Immunology and Immunopathology 12/1986; 13(3):213-26. · 2.08 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: An immunogold method in Terasaki plates is described which allows accurate and sensitive visualization of the binding of monoclonal antibodies to cell surface antigens and is suitable for large scale screening. Monolayers of fixed cells are prepared in the wells. The binding of monoclonal antibodies is detected by a protein A gold complex. The cell-bound gold can be visualized by either optical or transmission electron microscopy. The results obtained with various monoclonal antibodies are presented.
Journal of Immunological Methods 03/1985; 76(2):211-22. · 2.20 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A monoclonal antibody termed B2 Val 7C7, was produced by the fusion of xenoimmune mouse spleen cells with Sp2/0.Ag 14 myeloma cells. This antibody is specific for a polymorphic lymphocyte antigen; it was detected on cells from 138 out of 177 cattle by both 125I-labelled protein A (solid-phase radioimmunoassay, SPRIA) and gold-labelled protein A (immunogold). Its binding was tested on various cell types (peripheral blood lymphocytes, monocytes, polymorphonuclear cells (PMN), thymocytes) from a variety of normal bovine donors. On the one hand, B2 Val 7C7 detects a determinant present on all IgG-bearing lymphocytes, on 20% of the non-IgG-bearing lymphocytes and on the majority of the monocytes. On the other hand, no binding occurs on any PMN or thymocytes. The detected membrane antigen was isolated by immunoprecipitation from an NP 40 extract of 3H-leucine-labelled cells. On SDS-PAGE, it appears to be composed of two sub-units: a 32 000-dalton and a 27 000-dalton chain. These results show that B2 Val 7C7 recognizes an alloantigenic specificity present on an Ia-like antigen.
Animal blood groups and biochemical genetics 02/1983; 14(4):239-50.
-
[show abstract]
[hide abstract]
ABSTRACT: Non-enterotoxigenic type A Clostridium perfringens are associated with bovine enterotoxaemia, but the α toxin is not regarded as responsible for the production of typical lesions of necrotic and haemorrhagic enteritis. The purpose of this study was to investigate the putative role of the more recently described β2 toxin. Seven hundred and fourteen non-enterotoxigenic type A C. perfringens isolated from 133 calves with lesions of enterotoxaemia and high clostridial cell counts (study population) and 386 isolated from a control population of 87 calves were tested by a colony hybridisation assay for the β2 toxin. Two hundred and eighteen (31%) C. perfringens isolated from 83 calves (62%) of the study population and 113 (29%) C. perfringens isolated from 51 calves (59%) of the control population tested positive with the β2 probe. Pure and mixed cultures of four C. perfringens (one α+β2+, one α+enterotoxin+ and two α+) were tested in the ligated loop assay in one calf. Macroscopic haemorrhages of the intestinal wall, necrosis and haemorrhages of the intestinal content, and microscopic lesions of necrosis and polymorphonuclear and mononuclear cell infiltration of the intestinal villi were more pronounced in loops inoculated with the α and β2-toxigenic C. perfringens isolate. These results suggest in vivo synergistic role of the α and β2 toxins in the production of necrotic and haemorrhagic lesions of the small intestine in cases of bovine enterotoxaemia. However, isolation of β2-toxigenic C. perfringens does not confirm the clinical diagnosis of bovine enterotoxaemia and a clostridial cell counts must still be performed.
Veterinary Microbiology.
