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W Leibold

Publications and source records attributed to W Leibold.

At least 55 records · Page 3Linked to original sources
PubMed1996

Reactivity of monoclonal antibodies with bovine blood mononuclear cells activated by mitogens and superantigens.

Monoclonal antibodies forming seven preliminary clusters in the third ruminant CD workshop (PC15, 16b, 16c, 20b, 26b, 26c and 30) were analysed by flow cytometry upon reaction with in vitro stimulated bovine mononuclear cells. Concanavalin A (Con A), pokeweed mitogen (PWM) and three Staphylococcus aureus enterotoxins (superantigens SEA, SEB and SEC2) were used as stimulating agents. The mAbs in PC15, 16c and 26b reacted uniformly irrespective of the stimulating agent, in contrast to clusters PC16b, 20b, 26c and 30, which could be subgrouped according to differential reaction pattern depending on mitogen or superantigen stimulation. The mAbs CC28 and CACT114A seem to detect an antigen preferably induced by superantigens. MAb GB16A was shown to react strongly with Con A. Depending on the activation antigen, its time course of expression was either the same upon superantigen stimulation as that for mitogen-stimulated cells or slightly delayed.

Animals↗
PubMed1996

Reactivity of workshop antibodies with a non-ruminant species: crossreactivity with canine blood leukocytes.

Three-hundred and eight monoclonal antibodies detecting surface determinants on ruminant cells were tested on canine leukocytes by flow cytometry. Thirty mabs showed crossreactivity: 25 of them reacted uniformly with cells of three unrelated dogs, five displayed a polymorphic reaction pattern. Thus, in addition to mabs with yet unknown specificity, antibodies to ruminant WC9, B-cell antigens and possible CD29, CD49d cross-react with canine cells, and probably react with the homologous canine antigen.

Animals↗
PubMed1995

Monoclonal equine IgM and IgG immunoglobulins.

In order to define equine immunoglobulins (Igs) and to produce monoclonal reference Igs we fused equine peripheral blood mononuclear cells with X63-Ag8.653 non Ig producing murine myeloma cells. A total of 29 equine Ig producing equi-murine heterohybridomas were obtained, of which ten expressed equine Ig for more than 3 months. One of these heterohybridoma lines produced monoclonal IgM, an equine isotype which has not been available in monoclonal form before. Four lines secreted equine IgG of two distinct Ig heavy chain types as assessed by the molecular weight (MW), while the remaining five lines expressed only equine Ig light chains. A sixth Ig light chain expressing variant was obtained by cloning of one of the IgG producing heterohybridoma lines. These monoclonal IgGs were compared with previously described equine IgG monoclonal antibodies (mabs) by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). According to their MW we identified five groups of gamma-chains and four groups of Ig light chains.

Animals↗
PubMed1994

Proteins induced by recombinant equine interferon-beta 1 within equine peripheral blood mononuclear cells and polymorphonuclear neutrophilic granulocytes.

Peripheral blood mononuclear cells (PBMC) and polymorphonuclear neutrophilic granulocytes (PMN) as well as embryonic equine dermal fibroblasts and the equine fibroblast line E. Derm which were used as controls, were treated with recombinant equine interferon-beta 1 (rEqIFN-beta 1) in vitro which induced the expression of different proteins in these cells. A 74 kDa protein was induced in PBMC and an 82 kDa protein was additionally found in the equine fibroblast E. Derm cell line following treatment with rEqFN-beta 1. Both proteins reacted with anti-mouse and anti-human Mx protein antisera in immunoblot tests. The 74 kDa and perhaps the 82 kDa components may thus represent equine 'Mxanalogous proteins'. The 74 kDa protein was only detected in PBMC of ten out of 20 horses examined. The induction of Mx protein in the horse by Type 1 interferon may therefore resemble that in the mouse, where Mx protein is involved in selective resistance to influenza virus. The influence of rEqIFN-beta 1 on protein expression in equine PBMC and PMN was monitored by metabolic labeling and 2-D gel electrophoresis. Proteins of 82, 74, 58 and 40 kDa were induced in PBMC following exposure to rEqIFN-beta 1. A constitutively expressed 35 kDa protein, however, was no longer demonstrable upon treatment with interferon. None of the proteins induced within PBMC was found in highly purified PMN treated with interferon. PMN exposed to rEqIFN-beta 1 synthesized four proteins in the range of 25 to 27 kDa. These proteins have not been described in interferon-treated PMN of any other species.

Animals↗
PubMed1993

Single and dual labelling of cytotoxic target cells. Comparison of three radioactive tracers, [35S]methionine, [75Se]selenomethionine, and chromium-51.

[75Se]selenomethionine (75SeM) has been shown to provide several advantages over Na(2)51CrO4 (51Cr) labelling of metabolizing target cells: high labelling efficiency and low spontaneous release of 75SeM-labelled target cells permit improved monitoring of cytotoxicity due to extended effector/target ratios in short- and long-term assays. Unfortunately, 75SeM will soon be difficult to obtain. Therefore we studied the suitability of [35S]methionine (35SM) as a substitute for 75SeM. Furthermore, we explored the potential of dual labelling of suspension target cells applying combinations of 35SM and 51Cr or 75SeM and 51Cr. 35SM is a suitable substitute for 75SeM retaining most of the advantages of 75SeM labelling. Although considerably higher labelling of cells is possible we obtained the most efficient labelling with 100-400 kBq/ml of 35SM or 75SeM resulting in a relatively high uptake (3-15 cpm/cell) and very low spontaneous release (1-2%/h) up to 24 h. This permits short- and long-term cytotoxic assays and the use of low numbers of target cells (1 x 10(3)) providing increased cytotoxic sensitivity with reduced amounts of effector cells. Suitable dual labelling of target cells with 35SM plus 51Cr or 75SeM plus 51Cr documented convincingly identical release kinetics for 35SM and 75SeM but partially discordant ones for 51Cr. Depending on the target cell used dual labelling permits discrimination and monitoring of different cytotoxic or release mechanisms in cellular cytotoxicity.

Chromium Radioisotopes↗
PubMed1993

Leukocyte adhesion deficiency in a Dutch Holstein calf: a case with a clear-cut family history.

A leukocyte adhesion deficiency characterized by recurrent (predominantly bacterial) infections, lack of extravascular polymorphonuclear leukocyte (PMN) and pus formation has been described first in humans and then in dogs, and recently also in cattle. Because of important clinical similarities, a unitary explanation for the leukocyte adhesion deficiency (LAD) syndrome in mammals is proposed, inasmuch that an intrinsic leukocyte defect (i.e. mutations in genes encoding the common CD18 subunit), is thought to cause the disease. However, thus far, the hallmark of such intrinsic leukocyte defects, notably their heritability (or familial incidence), has not (yet) been unequivocally demonstrated. This is the first report to describe the occurrence of four Dutch bovine LAD (BLAD) cases with the clearest familial clustering observed to date. The diagnosis was based on the clinical features of very poor thriving, in general, of the calves, hyperneutrocytosis without appreciable left shift, and the absence of PMN CD11a, or CD11b, or CD11c using monoclonal antibodies (mAb) and/or Concanavalin A binding activity of PMN lysates in immunoblots. Interestingly, a familial clustering was observed also for below-normal PMN CD11c expression. Thus, a cow with low CD11c expression (50.4%) and delivering three of the study BLAD calves, also had a healthy descendant with low (44.9%) PMN CD11c expression. These findings suggested the possibility that both subnormal expression and lack of PMN CD11 expression are inheritable factors in cattle. Furthermore, a large prospective study using the present mAb for selecting relatives expressing the complete spectrum (0 to > or = 90%) of PMN CD11/CD18 expression would create a comprehensive study population for understanding both the role of genetic factors and of survival strategies in BLAD.

Animals↗
PubMed1992

Induction of the 68 kDa major heat-shock protein in different Theileria annulata- and virus-transformed bovine lymphoblastoid cell lines.

Expression of the major inducible heat-shock protein of 68 kDa (hsp68) has been analyzed in peripheral blood mononuclear cells (PBMC) from cattle and in six Theileria annulata- and two bovine leukemia virus-transformed bovine lymphoblastoid cell lines (BoLCL). By metabolic labeling, hsp68 could be detected in PBMC and BoLCL only after heat-shock, but not under normal culture conditions. Immunoblot analysis with an hsp68 reactive monoclonal antibody similarly revealed a strong hsp68 response after heat-shock in BoLCL, and no hsp68 expression under normal culture conditions. Normally kept PBMC, however, were weakly positive with the antibody. The data are discussed with respect to the constitutive expression of hsp68 seen in several other cell lines.

Animals↗
PubMed1992

"Discordant" influence of equine recombinant interferon-beta 1 on the cytotoxic capacity of equine polymorphonuclear neutrophils and peripheral blood mononuclear cells in vitro and in vivo.

The influence of recombinant equine interferon-beta 1 (rEqIFN-beta 1) on mononuclear cells of peripheral blood (PBMC) and polymorphonuclear neutrophilic granulocytes (PMN) was tested under in vitro and ex vivo conditions. Treatment of equine PBMC with IFN in vitro enhanced the antibody-independent cytotoxicity (AICC) and antibody-dependent cytotoxicity (ADCC) while there was no significant effect on the cytotoxic capacity of PMN treated with rEqIFN-beta 1 in vitro. Ex vivo there was an increased capacity of AICC and ADCC upon single or multiple application of rEqIFN-beta 1 in PMN, only. Treatment with rEqIFN-beta 1 thus induced an increased cellular cytotoxicity in vitro and in vivo but in different populations of peripheral blood cells. In vivo rEqIFN-beta 1 causes a pronounced activation of PMN but not of PBMC as cytotoxic effector cells. This might be achieved indirectly, e.g., by cytokines produced by IFN-sensitive cells.

Animals↗
PubMed1992

A method for the assay of "difficult" interferons exemplified with recombinant equine interferon-beta 1.

We wished to assay recombinant equine interferon-beta 1 (rEqIFN-beta 1) but could not obtain satisfactory results with previously described methods. Therefore, we developed a yield-reduction assay, using primary horse peripheral blood mononuclear cells (PBMC) with vesicular stomatitis virus (VSV) for challenge, which proved consistently satisfactory and highly sensitive. It is suggested that this method of assay may be useful for IFNs from other animals where problems are encountered.

Animals↗
PubMed1992

Investigations on course and outcome of phocine distemper virus infection in harbour seals (Phoca vitulina) exposed to polychlorinated biphenyls. Virological and serological investigations.

The influence of polychlorinated biphenyls (PCBs) on phocine distemper virus (PDV) infections in harbour seals (Phoca vitulina) was studied. Six out of ten seals had been conditioned with a defined mixture of PCB-congeners for several weeks. Following exposure to the cell culture-propagated PDV isolate 2558/Han 88 the complete clinical picture of "1988 seal plague" was provoked in all ten seals inoculated. Four out of six PCB-conditioned seals and two out of four seals not loaded with PCBs succumbed to the infection within three weeks post inoculation. With regard to the clinical course, duration of cell-associated viremia, PDV-antigen distribution in tissues of fatally infected seals and the humoral immune response to PDV no differences between PCB-loaded and unloaded seals were recognized. Evidence was obtained that the pathogenesis of experimental PDV-infection in harbour seals shares some features with those of canine distemper in terrestrial carnivores. In contrast, however, to experimental distemper infection of gnotobiotic dogs prompt development of high titres of PDV-specific IgG did not correlate with recovery from infection.

Animals↗
PubMed1992

Monitoring of effects induced by recombinant equine interferon-beta 1 in whole blood and separated fractions of peripheral blood of horses.

Interferon is known to induce antiviral mechanisms and to exert immunoregulatory capacities on various cell types. The antiviral capacity of recombinant equine interferon-beta 1 (rEqIFN-beta 1) is most sensitively monitored by indirect quantitation of multiplication of vesicular stomatitis virus (VSV) in blood cells of horses. As few as 0.5 pg rEqIFN-beta 1/ml can be assessed by means of 90% reduction of VSV-replication in whole blood (w.b.) as well as in isolated mononuclear blood cells (MNC) in spite of individual variations. The immunoregulatory influence of 20-50 pg rEqIFN-beta 1/ml is sufficient to cause at least a 50% reduction of mitogen-induced lymphocyte proliferation in MNC, while higher concentrations are needed in w.b. Of the mitogens tested the best stimulation of proliferation on the equine lymphoid cells was obtained with staphylococcal enterotoxin B (SEB). Release of reactive oxygen species (ROS) from phagocytic cells in w.b. or from isolated polymorphonuclear cells (PMN) as monitored by chemiluminescence (CL) does not seem suitable for evaluation of rEqIFN-beta 1-induced immunoregulation as only very high rEqIFN-beta 1-concentrations (10(3)-10(4) pg/ml) result in a minute increase (up to 20%) of CL. Comparative studies on w.b. and isolated leukocyte fractions from identical specimens of individual horses suggest that monitoring of antiviral and distinct immunoregulatory capacities of rEqIFN-beta 1 can be performed on w.b. without loss of information and sensitivity as compared to isolated MNC.

Animals↗
PubMed1992

Isolation of a high-molecular mass glycoprotein from culture supernatant of an arthritogenic strain of the bacteria Erysipelothrix rhusiopathiae reacting with "inductive" monoclonal antibodies derived from rats with erysipelas polyarthritis.

A glycoprotein exhibiting a relative molecular mass of about 1000 kDa was purified to homogeneity from culture supernatant of arthritogenic bacteria (Erysipelothrix rhusiopathiae, strain T28) by ultrafiltration, ammonium sulfate precipitation, molecular mass exclusion, and ion exchange chromatography. Fractions obtained were analysed for their antigenic content by an enzyme linked immunosorbent assay (ELISA) using rabbit immune serum raised against this strain of Erysipelothrix rhusiopathiae. Distinct monoclonal antibodies obtained from rats suffering from erysipelas polyarthritis display a unique property by inducing very efficiently protective and regulatory mechanisms while being unable to generate classical "passive immunity". These "inductive" monoclonal antibodies recognize most likely linear epitopes on the purified glycoprotein. This makes it a prime source for analysing the target structure of these in vivo "inductive" antibodies.

Animals↗
PubMed1992

Monoclonal antibodies preventing the development of polyarthritis in rats induced by experimental infection with erysipelas bacteria.

Monoclonal IgM-antibodies specific for arthritogenic erysipelas bacteria (Erysipelothrix rhusiopathiae, serovar 2, strain T28) were isolated from rats suffering from erysipelas polyarthritis. Four of them (C52, D9, E51, R117) were administered to syngeneic Lewis rats. While D9 and an unrelated rat-IgM-antibody showed no effect, C52 protected partially and R117 as well as E51 fully from all symptoms of erysipelas polyarthritis. Prevention of the disease was associated with a lack of antibody-formation against the erysipelas bacteria. There is evidence that prevention is not due to classical passive immunization, but rather to induction of host mechanisms efficiently activated by "inductive" monoclonal antibodies.

Animals↗
PubMed1992

One-dimensional isoelectric focusing and immunoblotting of equine major histocompatibility complex class I antigens.

The cells of 60 randomly selected Hannoveranian warm-blooded horses were subjected to one-dimensional isoelectric focusing and immunoblotting with a cross-reacting monoclonal antibody (Bo 1) recognizing bovine class I antigens. The banding patterns were correlated with the serologically defined specificities of the ELA-A locus. ELA-A2 was correlated with four bands, while ELA-A5, ELA-W18, ELA-A6, ELA-A14 and ELA-A9 were correlated with a single band each. The complexity of the pattern and additional polymorphic bands which could not be correlated to any of the known ELA specificities may indicate biochemical variants of established serological specificities or still-undetected allelic products of more than one class I locus expressed at the surface of horse cells. Here we present the first description of the biochemical complex polymorphism of equine MHC class I molecules using one-dimensional isoelectric focusing. Direct comparison of biochemical and serological polymorphisms revealed potentials and limitations of both techniques which supplement each other. Their combination will improve and enhance the definition of expressed products of different loci in the ELA class I region.

Animals↗
PubMed1992

Changes in rat leukocyte populations in peripheral blood, spleen, lymph nodes, and synovia during Erysipelas bacteria-induced polyarthritis.

Kinetics of leukocyte subsets were followed for several weeks in rats suffering from polyarthritis induced by experimental infection with erysipelas bacteria (Erysipelothrix rhusiopathiae, serovar 2, strain T28). A marked leukocytosis was found in peripheral blood, and, with some delay, in the synovia and draining lymph nodes of affected joints. In the lymphoid organs tested considerable blast formation of lymphoid cells with a paucity of polymorphonuclear granulocytes was found, while the latter represented the majority of leukocytes in acutely inflamed joints. Cells isolated from spleen showed only moderate and transient alterations in proportions of subpopulations during the first week after inoculation of erysipelas bacteria. In contrast, cells isolated from synovia of inflamed joints and draining lymph nodes displayed more intense and longer lasting alterations: In arthritic animals, the proportion of MHC class II-positive lymphocytes generally increased and remained elevated at least during the first three weeks of the disease. Spontaneous release of IL-2 from cells isolated up to 20 days post induction of the arthritis indicated a considerable activation of lymphocytes in vivo. Interestingly, with exception of synovia, the relative amount of T-lymphocytes including their major CD4+ and minor CD8+ subsets showed little alteration during the course of the disease. Much more pronounced were the rapidly and the extent the membrane Ig-positive B-lymphocytes increased in the synovia as well as in the lymph nodes. Thus, B-lymphocytes may be of particular relevance for elucidating pathomechanisms of erysipelas polyarthritis.

Animals↗
PubMed1991

Joint Report of the Fourth International Bovine Lymphocyte Antigen (BoLA) Workshop, East Lansing, Michigan, USA, 25 August 1990.

Blood samples from 54 animals were exchanged between 15 laboratories in nine countries to improve and expand BoLA class I and class II typing. A total of 27 out of 33 (82%) of previously accepted BoLA-w specificities were represented within the cell panel. Seventeen new serum-defined BoLA specificities were accepted by the workshop participants, thus expanding the number of internationally recognized BoLA specificities to 50. The large number of new specificities detected resulted from the number of serological reagents used (n = 1139) and the genetic diversity of the cell panel. Confidence derived from the high percentage of agreement between the laboratories on antigen detection (97.3%; r = 0.84) permitted the removal of the workshop (w) notation from 23 BoLA-w specificities and their acceptance as full status BoLA-A antigens. Two new non-BoLA antigens were also detected, one completely included within the red blood cell factor S' (BoLy-S'), whereas a second (BoLy-w1) did not show any association with tested red blood cell factors. A comparison between serological, isoelectric focusing (IEF) and DNA typing for BoLA class II polymorphism was conducted with a subset of workshop cells. Correlation between the three methods was significant for three combinations of alleles. Three other serologically defined class II specificities were correlated with DR and/or DQ restriction fragment length polymorphism (RFLP) types, whereas six additional IEF types were correlated with DR and/or DQ RFLP types (r greater than or equal to 0.50). Several new IEF, DRB, DQA and DQB RFLP patterns were identified. In 46 animals that were typed for BoLA-DR and DQ genes by RFLP analysis, 46 different BoLA haplotypes were tentatively defined. These 46 haplotypes were distinguished by 31 serologically-defined BoLA-A alleles (and 2 'blanks'), 15 DRB RFLP types (plus up to 10 new DRB RFLP patterns) and 23 DQA-DQB haplotypes.

Animals↗