References of "Heinen, Ernst"
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See detailFollicular dendritic cells related to nerve fibres and cellular prion protein expression in ileal and jejunal Peyer’s patches of cows and calves
Defaweux, Valérie ULg; Antoine, Nadine ULg; Dorban, G. et al

Poster (2005, February)

Prion pathogenesis following oral exposure is thought to involve gut-associated lymphoid tissue, which includes Peyer’s patches (PP). Before neuroinvasion, early accumulation of infectious prion protein ... [more ▼]

Prion pathogenesis following oral exposure is thought to involve gut-associated lymphoid tissue, which includes Peyer’s patches (PP). Before neuroinvasion, early accumulation of infectious prion protein (PrPsc) takes place on follicular dendritic cells (FDC) which are resident cells in germinal centres. The strain, the infection pathway and the lesions in the central nervous system are similar between bovine spongiform encephalopathy (BSE) and variant Creutzfeldt Jakob diseases. But in BSE, the agent tropism differs from lymphoid organs. Only bovine ileal PP are infectious. In order to study the replication and the possible ways of neuroinvasion of PrPsc in bovine PP, we studies the expression of cellular prion protein (PrPc), necessary for PrPsc accumulation, and compared the innervation of germinal centres related to FDC on ileal and jejunal PP of cows and calves. We performed classical immunoperoxydase staining and double immunofluorescence staining analyzed with a confocal microscopy. Differences in the innervation of germinal centres and expression of PrPc were evident. More contacts between FDC and nerve fibres are observed in calves PP. PrPc expression, carried out with different anti-PrPc antibodies, highlighted a heterogeneous labelling between calves and cows PP. Such results permit us to show that the innervation of PP is a dynamic process which could influence the first way of neuroinvasion in prion diseases. Moreover differences in the affinity of some antibody for PrPc allow us to postulate that PrPc glycoforms differ with age of bovines and thus could interfere with PrPsc tropism. [less ▲]

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See detailInterfaces between dendritic cells, other immune cells, and nerve fibres in mouse Peyer's patches: Potential sites for neuroinvasion in prion diseases
Defaweux, Valérie ULg; Dorban, Gauthier ULg; Demonceau, Christine ULg et al

in Microscopy Research and Technique (2005), 66(1), 1-9

In this study, we examined where immune cells and nerve fibres are located in mouse Peyer's patches, with a view to identifying potential sites for neuroinvasion by prions. Special attention was paid to ... [more ▼]

In this study, we examined where immune cells and nerve fibres are located in mouse Peyer's patches, with a view to identifying potential sites for neuroinvasion by prions. Special attention was paid to dendritic cells, viewed as candidate transporters of infectious prion. Double immunofluorescence labellings with anti-CD11c antibody and marker for other immune cells (B cells, T cells, follicular dendritic cells) were carried out and analysed by confocal microscopy on Peyer's patch cryosections. To reveal the extensive ganglionated networks of the myenteric and submucosal plexi and the sparse meshworks of nerve strands, we used antibodies directed against different neurofilament subunits or against glial fibrillary acidic protein. In the suprafollicular dome, dendritic cells connect, via their cytoplasmic extensions, enterocytes with M cells of the follicle-associated epithelium. They are also close to B and T cells. Nerve fibres are detected in the suprafollicular dome, notably in contact with dendritic cells. Similar connections between dendritic cells, T cells, and nerve fibres are seen in the interfollicular region. Germinal centres are not innervated; inside them dendritic cells establish contacts with follicular dendritic cells and with B cells. After immunolabelling of normal prion protein, dendritic cells of the suprafollicular dome are intensely positive labelled. (c) 2005 Wiley-Liss, Inc. [less ▲]

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See detailDetection of biomarkers of pathogenic bacteria by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
Ruelle, Virginie; Elmoualij, Benaïssa ULg; Zorzi, Willy ULg et al

in Lichtfouse, Eric; Schwarzbauer, Jan; Robert, Didier (Eds.) Environmental Chemistry : Green Chemistry and Pollutants in Ecosystems (2005)

In recent years, various mass spectrometry procedures has been developed for identifying bacteria. The accuracy and speed with which data can be obtained by Matrix-assisted laser Desorption/Ionization ... [more ▼]

In recent years, various mass spectrometry procedures has been developed for identifying bacteria. The accuracy and speed with which data can be obtained by Matrix-assisted laser Desorption/Ionization Time-of-flight Mass Spectrometry (MALDI-TOF-MS) make this an advantageous technique for environmental monitoring. However, minor variations in the sample preparation can influence the mass spectra significantly. In the present study, we have introduced a procedure to prepare bacteria by microextraction and we have optimized experimental parameters for rapid identification by MALDI-TOF-MS of whole bacterial cells isolated from environmental samples such as wastewater and soil. [less ▲]

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See detailImmunoquantitative PCR for prion protein detection in sporadic Creutzfeldt-Jakob disease.
Gofflot, Stéphanie ULg; Deprez, Manuel ULg; Elmoualij, Benaïssa ULg et al

in Clinical Chemistry (2005), 51(9), 1605-11

BACKGROUND: The most common human prion disorder is Creutzfeldt-Jakob disease (CJD); it includes sporadic, familial, iatrogenic, and variant subtypes. Diagnostic tests aim at detection with the highest ... [more ▼]

BACKGROUND: The most common human prion disorder is Creutzfeldt-Jakob disease (CJD); it includes sporadic, familial, iatrogenic, and variant subtypes. Diagnostic tests aim at detection with the highest specificity of very small deposits of abnormal prion protein (PrP). METHODS: We used immunoquantitative PCR (iqPCR) to detect proteinase K-resistant PrP (PrPRes) in tissue from the middle frontal gyrus of 7 patients with sporadic CJD and 7 non-CJD cases. We compared iqPCR with routine optimized ELISA, Western blotting, and immunohistochemical analyses. RESULTS: The 4 methods showed similar 100% sensitivity and specificity for the diagnosis of CJD. Along with high specificity, however, iqPCR had a threshold for PrP(Res) detection at least 10-fold lower than that of the classic ELISA. CONCLUSIONS: iqPCR is a new method for PrPRes detection that combines 100% specificity with a detection threshold at least 10-fold lower than classic techniques. This method may improve the detection of minute PrPRes deposits in tissues and body fluids and thus be useful for diagnostic and sterilization applications. [less ▲]

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See detailInteraction of the 106-126 prion peptide with lipid membranes and potential implication for neurotoxicity.
Dupiereux-Fettweis, Ingrid ULg; Zorzi, Willy ULg; Lins, Laurence ULg et al

in Biochemical and Biophysical Research Communications (2005), 331(4), 894-901

Prion diseases are fatal neurodegenerative disorders characterized by the accumulation in the brain of an abnormally misfolded, protease-resistant, and beta-sheet rich pathogenic isoform (PrP(SC)) of the ... [more ▼]

Prion diseases are fatal neurodegenerative disorders characterized by the accumulation in the brain of an abnormally misfolded, protease-resistant, and beta-sheet rich pathogenic isoform (PrP(SC)) of the cellular prion protein (PrP(C)). In the present work, we were interested to study the mode of prion protein interaction with the membrane using the 106-126 peptide and small unilamellar lipid vesicles as model. As previously demonstrated, we showed by MTS assay that PrP 106-126 induces alterations in the human neuroblastoma SH-SY5Y cell line. We demonstrated for the first time by lipid-mixing assay and by the liposome vesicle leakage test that PrP 106-126, a non-tilted peptide, induces liposome fusion thus a potential cell membrane destabilization, as supported by membrane integrity assay (LDH). By circular dichroism (CD) analysis we showed that the fusogenic property of PrP 106-126 in the presence of liposome is associated with a predominantly beta-sheet structure. These data suggest that the fusogenic property associated with a predominant beta-sheet structure exhibited by the prion peptides contributes to the neurotoxicity of these peptides by destabilizing cellular membranes. The latter might be attached at the membrane surface in a parallel orientation as shown by molecular modeling. [less ▲]

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See detailDiscrimination self/non-self
Heinen, Ernst ULg

in Encyclopedia of Life Sciences (2005)

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See detailGerminal center
Thielen, C.; Heinen, Ernst ULg

in Encyclopedia of Life Sciences (2005)

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See detailImmuno-quantitative polymerase chain reaction for detection and quantitation of prion protein
Gofflot, Stéphanie ULg; Elmoualij, Benaïssa ULg; Zorzi, Danièle ULg et al

in Journal of Immunoassay & Immunochemistry (2004), 25(3), 241-258

Immuno-polymerase chain reaction (PCR) is an extremely sensitive detection method, combining the specificity of antibody detection and the sensitivity of PCR. We have developed an immuno-quantitative PCR ... [more ▼]

Immuno-polymerase chain reaction (PCR) is an extremely sensitive detection method, combining the specificity of antibody detection and the sensitivity of PCR. We have developed an immuno-quantitative PCR (iqPCR), exploiting real-time PCR technology, in order to improve this immuno-detection method and make it quantitative. To illustrate the advantages of iqPCR, we have compared it with a conventional enzyme linked immuno sorbent assay (ELISA) technique in experiments aimed at detecting the cellular and the resistant form of prion protein in bovine brain extract. The iqPCR technique proved to be more sensitive than ELISA, so it could be a technique of choice for the diagnosis of infected animals both at an ante mortem and post-mortem stage. [less ▲]

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See detailDistribution of nerve fibers and prion protein expression in mouse Peyer's patches
Defaweux, Valérie ULg; Dorban, G; Demonceau, C et al

Poster (2004, July)

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

in Veterinary Immunology and Immunopathology (2004), 97(1-2), 1-9

Follicular dendritic cells (FDCs) are a unique population of accessory cells located in the light zone of the germinal centres of lymphoid follicles. Their involvement in the generation of Immoral immune ... [more ▼]

Follicular dendritic cells (FDCs) are a unique population of accessory cells located in the light zone of the germinal centres of lymphoid follicles. Their involvement in the generation of Immoral immune responses implies a potential role for these cells in many disorders. Indeed, 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 lymphoid organs. The identification of FDC is useful for the analysis of their distribution in reactive lymphoid tissue as well as in pathological conditions. The production and characterisation of a new mouse monoclonal antibody directed against bovine follicular dendritic cells (FDC-B1) is reported. The antigen detected by FDC-B1 is expressed exclusively on the surface of FDCs in ruminant lymphoid organs. The antigen has an approximate molecular weight of 28 kDa. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

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See detailAvis n° 24 du 13 octobre 2003 relatif aux cellules souches humaines et au clonage thérapeutique
Pennings, G.; Michel, L.; Vermeersch, E. et al

Report (2003)

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See detailDistribution of nerve fibres and prion protein expression in mice Peyer’s patches
Defaweux, Valérie ULg; Dorban, G.; Demonceau, C. et al

Poster (2003, October)

Prion pathogenesis following oral exposure is thought to involve gut-associated lymphoid tissue, which includes Peyer’s patches (PP). The antigens enter into the underlying lymphoid tissue organized in PP ... [more ▼]

Prion pathogenesis following oral exposure is thought to involve gut-associated lymphoid tissue, which includes Peyer’s patches (PP). The antigens enter into the underlying lymphoid tissue organized in PP through the medium of M cells. Infectious prion protein (PrPres) would probably take the same way of entry and like this initiate the first stage of lympho-invasion. Theoretically, intestinal lymphoid cells can come in contact with ingested PrPres and with nerve endings of the intramural system. The distribution pattern of the nerve fibres and lymphoid cells in PP and possible contact between these two elements implicated in neuroinvasion are not yet fully elucidated. In our study, classical immunoperoxydase staining and double immunofluorescence staining analysed with a confocal microscope has been carried out on C56Bl/6 mice PP. Immunoperoxidase and immunofluorescent CD11c stainings show numerous dendritic cells (DC) in the suprafollicular dome, close to the epithelium made of enterocytes and M-cells. Confocal studies show the presence of DC in the T cell zones of Peyer's patches, and also close to B cells in the follicule and to follicular dendritic cells (FDC) in the germinal centres. The PrPc expression, fundamental in the pathogenesis of prion diseases, is notably localized in germinal centres, co-localized with the FDC network and on cellular structures close to the epithelium, co-localized with DC. Nerve fibres have been immunostained in fluorescence using antibodies raised against neurofilaments High, Medium and Low and against glial fibrillary acidic protein (GFAP). Only GFAP staining revealed the presence of some nerve fibres in the suprafollicular dome, coursing the mucosal epithelium and also at the periphery of germinal centres in close connection with numerous dendritic cells. Such results permit us to postulate that these nerve fibres and PrPc positive dendritic cells, strategically positioned under the intestinal epithelium as well as in the germinal centres close to FDC network, highly expressing PrPc and thought to replicate PrPres, may be involved in the peripheral transport of the infectious prion protein. [less ▲]

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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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