References of "Heinen, Ernst"
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See detailPregnancy and the immune system: between tolerance and rejection
Thellin, Olivier ULg; Heinen, Ernst ULg

in Toxicology (2003), 185(3), 179-184

Interactions between the conceptus and the mother are bi-directional: the feto-placental tissues need nutrition and a suitable environment in homeostatic condition whereas the mother influenced by the ... [more ▼]

Interactions between the conceptus and the mother are bi-directional: the feto-placental tissues need nutrition and a suitable environment in homeostatic condition whereas the mother influenced by the placental factors adapts her metabolism and immune system. Many different mechanisms acting locally or at distance ensure tolerance of the semi-allogeneic graft by the maternal natural and adaptive immune defences. In front of this tolerance, mechanisms exist ensuring rejection of the conceptus by the mother (spontaneous abortion) through rupture of one or more tolerance mechanisms, notably in stress situations endangering the mother. Thus outcome of a pregnancy is dependent on efficiently working tolerance mechanisms, and rupture of such mechanisms can lead to rejection. The balance of influence leading either to tolerance or rejection is under control of internal (maternal and fetal) and external (environmental) factors. Rejection, if triggered, mainly occurs through immune-induced inflammation, tissue degradation and coagulation. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved. [less ▲]

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See detailFDC-B1, a new monoclonal antibody directed against bovine follicular dendrititic cells.
Defaweux, Valérie ULg; Mélot, France ULg; Jolois, Olivier ULg et al

Poster (2003, March)

Follicular dendritic cells (FDCs) are unique immunological accessory cells located in the light and dark zones of the germinal centres in lymph follicles. Characterized by long branching processes forming ... [more ▼]

Follicular dendritic cells (FDCs) are unique immunological accessory cells located in the light and dark zones of the germinal centres in lymph follicles. Characterized by long branching processes forming a three-dimensional network, FDCs create particular microenvironments for germinal centre B and T cells and contribute to the maturation of B cells into memory cells. An involvement of the FDCs is suspected in various disorders affecting lymphoid tissues, malignant lymphoma or in some viral diseases. Moreover, in prion diseases, FDCs seem to be the major sites of extraneuronal cellular prion protein expression and the principal sites of the infectious agent accumulation in lymph organs. Because no antibody commercially available was specific to bovine FDCs, a new monoclonal antibody directed against bovine FDCs (FDC-B1) has been produced and characterized in our laboratory. The antigen detected by FDC-B1 is expressed on FDC surfaces in ruminant (bovine, ovine and caprine) lymphoid organs. This protein seems to be a membrane glycoprotein of more or less 28 kDa whose sequence will be soon determined. Moreover, FDC-B1 can be used in various applications: immunofluorescence, immunoperoxidase, immunogold labellings and western blotting. FDCs are potential targets for therapy or prophylaxis in natural TSEs, such as bovine spongiform encephalopathies and scrapie. Thus, it appears of great interest to identify bovine and ovine FDCs in routine lymphoid tissues sections. An other application of this antibody to immunofluorescence histochemistry techniques will enable the study of possible direct contacts between bovine FDCs and nerve endings and thus clarify prions neuroinvasion scheme in the case of BSE and scrapie. [less ▲]

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See detailApoptosis induction in human cancer cells by sungucine from Strychnos icaja root
Frederich, Michel ULg; Bentires-Ali, M.; Tits, Monique ULg et al

in Naunyn-Schmiedeberg's Archives of Pharmacology (2003), 367(3), 260-265

Sungucine (SG) and isosungucine (ISG) are bisindole alkaloids characterized by a 5'-23 link between the two parts of the compounds, which are till now specific to Strychnos icaja. In this work, SG and ISG ... [more ▼]

Sungucine (SG) and isosungucine (ISG) are bisindole alkaloids characterized by a 5'-23 link between the two parts of the compounds, which are till now specific to Strychnos icaja. In this work, SG and ISG were submitted to the NCI's in vitro 60 human tumor cell line screen, where SG showed interesting selectivity (6X) against the tested leukemia cell lines. In HL60-treated cells, apoptosis was demonstrated by observation of apoptotic bodies formation, and phosphatidylserine exposition at cell surface. In HeLa-treated cells, the analysis of cellular cycle by flow cytometry showed G1 accumulation and a small sub-G1 peak that could be related to DNA fragmentation characteristic of apoptosis. The eventual role of p53 was analyzed using wild-type HCT-116 colon cancer cells. Nevertheless, p53 and Bax expression were not modified in SG-treated cells. The cleavage of PARP by caspase-3 protease proved that apoptosis was also induced in this line. These results demonstrate that SG induces apoptosis, but also necrosis, in human cancer cell lines. [less ▲]

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See detailDo Bovine Lymphocytes Express a Peculiar Prion Protein?
Mélot, France ULg; Thielen, Caroline ULg; Labiet, T. et al

in Developmental Immunology (2002), 9(4), 245-52

The cellular prion protein (PrPc) is a glycolipid-anchored cell surface protein that usually exhibits three glycosylation states. Its post-translationally modified isoform, PrPsc, is involved in the ... [more ▼]

The cellular prion protein (PrPc) is a glycolipid-anchored cell surface protein that usually exhibits three glycosylation states. Its post-translationally modified isoform, PrPsc, is involved in the pathogenesis of various transmissible spongiform encephalopathies (TSEs). In bovine species, BSE infectivity appears to be restricted to the central nervous system; few or no detectable infectivity is found in lymphoid tissues in contrast to scrapie or variant CJD. Since expression of PrPc is a prerequisite for prion replication, we have investigated PrPc expression by bovine immune cells. Lymphocytes from blood and five different lymph organs were isolated from the same animal to assess intra- and interindividual variability of PrPc expression, considering six individuals. As shown by flow cytometry, this expression is absent or weak on granulocytes but is measurable on monocytes, B and T cells from blood and lymph organs. The activation of the bovine cells produces an upregulation of PrPc. The results of our in vitro study of PrPc biosynthesis are consistent with previous studies in other species. Interestingly, western blotting experiments showed only one form of the protein, the diglycosylated band. We propose that the glycosylation state could explain the lack of infectivity of the bovine immune cells. [less ▲]

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See detailHuman immune cells express ppMCH mRNA and functional MCHR1 receptor
Verlaet, Myriam ULg; Adamantidis, Antoine ULg; Coumans, Bernard ULg et al

in FEBS Letters (2002), 527(1-3), 205-210

Melanin-concentrating hormone (MCH) is highly expressed in the brain and modulates feeding behavior. It is also expressed in some peripheral tissues where its role remains unknown. We have investigated ... [more ▼]

Melanin-concentrating hormone (MCH) is highly expressed in the brain and modulates feeding behavior. It is also expressed in some peripheral tissues where its role remains unknown. We have investigated MCH function in human and mouse immune cells. RT-PCR analysis revealed a low expression of prepro-MCH and MCH receptor 1 (MCHR1) but not of MCHR2 transcript in tissular and peripheral blood immune cells. FACS and in vitro assay studies demonstrated that MCHR1 receptor expression on most cell types can trigger, in the presence of MCH, cAMP synthesis and calcium mobilization in peripheral blood mononuclear cells (PBMCs). Moreover, MCH treatment decreases the CD3-stimulated PBMC proliferation in vitro. Accordingly, our data indicate for the first time that MCH and MCHR1 may exert immunomodulatory functions. (C) 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved. [less ▲]

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See detailSpermine induces precocious development of the spleen in mice
Jolois, Olivier ULg; Peulen, Olivier ULg; Collin, Serge ULg et al

in Experimental Physiology (2002), 87(1), 69-75

Spermine is a low molecular weight polyamine involved in the postnatal maturation of the gut. When it is administered orally to suckling rats, it induces maturation of the intestinal tract (liver ... [more ▼]

Spermine is a low molecular weight polyamine involved in the postnatal maturation of the gut. When it is administered orally to suckling rats, it induces maturation of the intestinal tract (liver, pancreas and small intestine). Here we show that this polyamine is able to induce precocious intestinal and splenic development in suckling mice. In fact, in 15-day-old mice which had received spermine orally twice daily for 3 days we observed an increase in the ratio of white pulp surface to total spleen surface in comparison with untreated mice. The two macrophage subsets of the marginal zone and the B-cell population were more developed and reached the development level of 5- or 10-week-old mice. The proliferation rate of B-cells was increased by spermine administration to pups. These observations suggest that spermine might play a role in immune system development; further investigation of its effects are intended, namely the evaluation of its capacity to enhance defence during the neonatal period. [less ▲]

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See detailDNA immunisation. New histochemical and morphometric data.
Ehirchiou, D.; Zorzi, Willy ULg; Biemans, R. et al

in European Journal of Histochemistry (2002), 46(3), 215-22

Splenic germinal center reactions were measured during primary response to a plasmidic DNA intramuscular injection. Cardiotoxin-pretreated Balb/c mice were immunized with DNA plasmids encodmg or not the ... [more ▼]

Splenic germinal center reactions were measured during primary response to a plasmidic DNA intramuscular injection. Cardiotoxin-pretreated Balb/c mice were immunized with DNA plasmids encodmg or not the SAG1 protein, a membrane antigen of Toxoplasma gondii. Specific anti-SAG1 antibodies were detected on days 16 and 36 after injection of coding plasmids. The results of ELISAs showed that the SAG1-specific antibodies are of the IgG2a class. Morphometric analyses were done on serial immunostained cryosections of spleen and draining or non-draining lymph nodes. This new approach made it possible to evaluate the chronological changes induced by DNA immunisation in the germinal centres (in number and in size). Significant increases in the number of germinal centres were measured in the spleen and only in draining lymph nodes after plasmid injection, the measured changes of the germinal centers appeared to result from the adjuvant stimulatory effect of the plasmidic DNA since both the coding and the noncoding plasmid DNA induced them. No measurable changes were recorded in the T-dependent zone of lymph organs. [less ▲]

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See detailNew Histochemical and Ultrastructural Observations on Normal Bovine Tonsils
Velinova, Maria; Thielen, Caroline ULg; Mélot, France ULg et al

in Veterinary Record : Journal of the British Veterinary Association (2001), 149(20), 613-7

Samples of normal bovine palatine tonsils were examined by light and electron microscopy. Like human tonsils, they were composed of crypts, subepithelial areas, follicles, and T-dependent zones, but their ... [more ▼]

Samples of normal bovine palatine tonsils were examined by light and electron microscopy. Like human tonsils, they were composed of crypts, subepithelial areas, follicles, and T-dependent zones, but their well-developed capsule subdivided the lymphoid tissue by connective septa. B cells formed the major lymphoid component. The follicles and T-dependent zones had morphological and histochemical features typical of peripheral lymph organs. Follicular dendritic cells were isolated and shown to be similar to human follicular dendritic cells. [less ▲]

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See detailIsolation of Bovine Follicular Dendritic Cells Allows the Demonstration of a Particular Cellular Prion Protein
Thielen, Caroline ULg; Mélot, France ULg; Jolois, Olivier ULg et al

in Cell & Tissue Research (2001), 306(1), 49-55

As interaction of cellular prion protein (PrPc) and the infectious agent (PrPres) appears to be a crucial pathogenic step promoted by homology, variation in PrPc isoforms on bovine immune cells may ... [more ▼]

As interaction of cellular prion protein (PrPc) and the infectious agent (PrPres) appears to be a crucial pathogenic step promoted by homology, variation in PrPc isoforms on bovine immune cells may explain the absence of infectivity in most bovine lymph organs. In this study, we examined PrPc expression in bovine lymph organs (tonsils and lymph nodes) and on isolated follicular dendritic cells (FDCs). We used a panel of different monoclonal antibodies (MoAbs) raised against different epitopes of prion protein. Two MoAbs recognise amino acids 79-92 (SAF 34 and SAF 32 Mo-Abs); the 6H4 antibody reacts with a specific peptide comprising the 144-152 amino acids, and the 12F10 MoAb recognises the sequence 142-160. After immunolabelling of frozen sections of lymph organs with 6H4 or 12F10 MoAbs, we detected cellular prion protein in germinal centres. However, using the SAF 34 or SAF 32 antibodies, PrPc was revealed outside the lymphoid tissues. No PrPc was observed in the germinal centres. Therefore, we adapted the method of FDC isolation, making it suitable for the study of PrPc expression on their surface. Using electron microscopy, the presence of PrPc on the surface of FDCs was demonstrated only with 6H4 MoAb. These results suggest that bovine follicular dendritic cells express a particular form of prion protein. Either the N-terminal part of PrPc is cleaved or the accessibility of the specific epitope (79-92) of SAF 34 MoAb is abolished by interaction with other molecules. This particular isoform of PrPc on bovine FDCs might be related to the apparent absence of infectivity in lymph organs in cattle affected by bovine spongiform encephalopathy. [less ▲]

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See detailMatrix-assisted laser desorption/ionisation time-of-flight mass spectrometric (MALDI-TOF-MS) characterisation of pathogenic bacteria isolated from wastewater
Zaballos, Milagros; Ruelle, Virginie; Bonjean, Nicolas et al

Poster (2001)

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See detailAdjustment of parameters involved in the detection and the identification of biomarker proteins of pathogenic bacteria by MALDI-TOF MS
Ruelle, Virginie; Zaballos, Milagros; Bonjean, Nicolas et al

Poster (2001)

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See detailLes bois de cerf : revue de littérature scientifique
Crigel, M-H; Balligand, Marc ULg; Heinen, Ernst ULg

in Annales de Médecine Vétérinaire (2001), 145

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