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Biomedical subjects

W Leibold

Publications and source records attributed to W Leibold.

At least 19 recordsLinked to original sources
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↗
PubMed1991

[Detection and possible therapy of granulocyte defects].

Following a short overview of anatomical distribution pattern and functions of neutrophils diagnostic methods of evaluating their different functions are summarized. Therapeutic uses for granulocyte-colony-stimulating factor are discussed.

Agranulocytosis↗
PubMed1991

[Differentiation and transplantation antigens on the surface of mononuclear cells of cattle, horses and dogs].

The determination of differentiation and transplantation antigens will be of growing importance in immune diagnosis for individual animals as well as for breeding purposes in populations. Differentiation antigens characterize subsets of cell populations and indicate their functional capacity while transplantation antigens represent markers of individuals of a species. Occurrence and significance of these antigenic systems are briefly reviewed.

Animals↗
PubMed1990

[Acute lead poisoning in a young cow (case report)].

Calves were treated with different doses of lead acetate to investigate the influence of chronic subclinical lead intoxication on the immune system. A seven months old heifer fell ill showing typical signs of acute lead intoxication. This animal had been fed 0.316 mg lead for three months and 5 mg Pb/kg body weight/day for 17 days afterwards. Following symptoms were observed: Derangement of the central nervous system, paresis of the left body side, motor paralysis of the chewing muscles and disturbances of swallowing activity. Furthermore tooth grinding and attempts to push against, or climb walls were seen. After a single dose (2g) Ca-EDTA the heifer recovered progressively in 18 days.

Animals↗
PubMed1987

Selective inhibition of human natural killing and antibody-dependent cellular cytotoxicity by a polyanion.

A high molecular polyanion, Liquoid, was found to inhibit at nontoxic concentrations (12-50 micrograms/ml) the natural killing (NK) and the antibody-dependent cellular cytotoxic (ADCC) activity of human peripheral blood mononuclear cells selectively. Whereas NK of the K 562 target cell was slightly or not at all affected, the spontaneous lysis of PDe-B-1, an EBV-transformed B-cell line, was strongly inhibited or even completely abolished. ADCC activity could only be inhibited by Liquoid if the target cells were mycoplasma-free, while the polyanion had no effect when mycoplasma-contaminated target cells were used. Liquoid did not alter the target binding capacity of the NK effector cells and did not activate monocytes or induce other suppressive cells. Alpha interferon, but neither beta nor gamma interferon, was able to neutralize the NK reduction. These results suggest that Liquoid inhibits a target cell-related, selective process in the post-binding stage of NK cell lysis.

Antibody-Dependent Cell Cytotoxicity↗