References of "Jolois, Olivier"
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See detailPoly(2-dimethylamino ethylmethacrylate)-Based Polymers To Camouflage Red Blood Cell Antigens
Cerda Cristerna, Bernardino Isaac ULg; COTTIN, Sophie ULg; Flebus, Luca ULg et al

in Biomacromolecules (2012), 13(4), 1172-1180

Poly(2-dimethylamino-ethylmethacrylate) (PDMAEMA) is a cationic polymer when dissolved in a 7.4 pH fluid. Owing to its ionic nature, this polycation interacts with the negatively charged cell membrane ... [more ▼]

Poly(2-dimethylamino-ethylmethacrylate) (PDMAEMA) is a cationic polymer when dissolved in a 7.4 pH fluid. Owing to its ionic nature, this polycation interacts with the negatively charged cell membrane surface of red blood cells (RBCs). The electrostatic self-assembly of PDMAEMA on RBCs membrane can be employed for inducing the formation of a polymeric shield camouflaging blood group antigens on RBCs as a valuable strategy for developing “universal RBCs” for blood transfusion. The purpose of this research was to evaluate the camouflaging ability of PDMAEMA homopolymers and PDMAEMA-copoly(nethylene glycol) copolymers differing in molecular weight and architecture. Surprisingly, the PDMAEMAs caused a partially masking, no masking, and sensitization of the same RBCs population. The MW and architecture of the polymers as well as temperature of PDMAEMA-RBCs treatment influenced the results observed. Herein, the very particular reactivity of PDMAEMAs and RBCs is analyzed and discussed. [less ▲]

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See detailKinetic study of the antibody response during the blood meal of Ixodes ricinus: Implication on plasma cell maturation in vivo and for anti-Ixodes vaccination
MENTEN, Catherine ULg; couvreur, B.; Jolois, Olivier ULg et al

in Vaccine (2011)

Anti-tick vaccination could be an ideal solution to prevent pathogen transmission, but none is currently available against Ixodes ticks. Recently, we showed that adult Ixodes ricinus infestation on mice ... [more ▼]

Anti-tick vaccination could be an ideal solution to prevent pathogen transmission, but none is currently available against Ixodes ticks. Recently, we showed that adult Ixodes ricinus infestation on mice decreases the specific antibody production to BSA injected during infestation. Here, a kinetic study of seric levels of BSA-specific antibodies was performed to evaluate the B memory cell differentiation in Balb/c mice and the capacity of specific B memory cells to respond to BSA during infestation. We concluded that the tick blood meal inhibits or impairs the local differentiation of mature B cells into plasma cells, but does not alter the formation of memory B cell. Accordingly, this mechanism should not be an impediment to anti-Ixodes vaccination. [less ▲]

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See detailVaincre le Stapylococcus aureus : antibiothérapie ou vaccination?
Jolois, Olivier ULg

Scientific conference (2009, January 08)

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See detailTravaux Pratiques de Biologies
Jolois, Olivier ULg

Learning material (2009)

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See detailInfluence of the Ixodes ricinus tick blood-feeding on the antigen-specific antibody response in vivo.
Menten-Dedoyart, Catherine ULg; Couvreur, B.; Thellin, Olivier ULg et al

in Vaccine (2008), 26(52), 6956-64

The blood meal of hard ticks such as Ixodes ricinus lasts several days. This is made possible by tick salivary factors that inhibit inflammation, haemostasis and the host immune response. We assessed the ... [more ▼]

The blood meal of hard ticks such as Ixodes ricinus lasts several days. This is made possible by tick salivary factors that inhibit inflammation, haemostasis and the host immune response. We assessed the latter on a model of immune response in vivo. A significant reduction of specific IgM and IgG levels was observed in BALB/c mice infested 5 days before injection with bovine serum albumin (BSA) and QuilA but not in mice infested 5 days after the immunization. This effect was not observed in mock-infested mice and could not be attributed to the use of anesthetics. The antibody response was not merely delayed and the Th(1)/Th(2) balance appeared not altered. T-dependent zones and germinal centers in lymph nodes draining the tick bite site showed no apparent morphological alterations or shift in T cell subpopulations. However, the spleens of tick-infested mice had also an enlarged red pulp, indicating an increased extramedullary haematopoietic activity. [less ▲]

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See detailIntroduction aux méthodes morphologies
Jolois, Olivier ULg

Learning material (2008)

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See detailApoptosis and cytolysis induced by giganteosides and hederacolchisides in HL-60 cells
Gerkens, Pascal; Dobson, Rowan ULg; tabatadze, Nino et al

in Anticancer Research (2007), 27

The viability, cytolysis and apoptosis-mediated cellular death induced by giganteosides D and E (Gig-D and Gig-E) and hederacolchisides A and A1 (Hcol-A and Hcol- A1) were analysed in HL-60 cells ... [more ▼]

The viability, cytolysis and apoptosis-mediated cellular death induced by giganteosides D and E (Gig-D and Gig-E) and hederacolchisides A and A1 (Hcol-A and Hcol- A1) were analysed in HL-60 cells. Materials and Methods: the end-point metabolic (WST1) and lactate dehydrogenase (LDH) assays were used. Cell cycle analysis and apoptosis were measured by flow cytometry, DNA laddering and caspase 3 analyses. Results: the HL-60 cell line was more sensitive to Hcol-A1 and Gig-D (IC50 3-5 ÌM) than to Gig-E and Hcol-A (IC50 8-13 ÌM; WST1 assay). This was related to LDH release. The induction of apoptosis could be detected without caspase 3 activation after 24 h of treatment. DNA fragmentation could be detected only with Gig-D. With Hcol- A1 and Gig-D, an accumulation of cells in the S-phase and an increase of cells in sub-G1 peak were observed. By the annexinV-fluorescein isothiocyanate (FITC)/7-aminoactinomycin D (AAD) assay, the majority of cells were in late apoptosis with Gig-D, and in necrosis with Hcol-A1. Conclusion: Hcol-A1 is more cytotoxic than Gig-D, followed by Gig-E and finally Hcol-A. This is related to a membrane permeabilization effect, leading to cytolysis [less ▲]

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See detailSufasalazine unveils a contact-independent HSV-TK/ganciclovir gene therapy bystander effect in malignant gliomas
Robe, Pierre ULg; Nguyen-Khac, Minh-Tuan ULg; Lambert, Frédéric ULg et al

in International Journal of Oncology (2007), 30(1), 283-290

The efficacy of HSV-TK/ganciclovir-based gene therapy on malignant gliomas largely relies on the amplitude of the bystander effect. In these experiments, the anti-inflammatory drug Sulfasalazine increased ... [more ▼]

The efficacy of HSV-TK/ganciclovir-based gene therapy on malignant gliomas largely relies on the amplitude of the bystander effect. In these experiments, the anti-inflammatory drug Sulfasalazine increased the HSV-TK/ganciclovir bystander effect in C6, 9L and LN18 cells but not in U87 glioma cells. Using bi-compartmental culture devices and conditioned medium transfer experiments, we showed that in C6, 9L and LN18 cells but not in U87 cells, Sulfasalazine also unveiled a new, contact-independent mechanism of HSV-TK/ganciclovir bystander effect. Upon treatment with ganciclovir, human LN18-TK but not U87-TK cells synthetized and released TNF-alpha in the culture medium. Sulfasalazine sensitized glioma cells to the toxic effect of TNF-alpha. and enhanced its secretion in LN18-TK cells in response to GCV treatment. The caspase-8 inhibitor Z-IETD-FMK and a blocking antibody to TNF-alpha both inhibited the contact-independent bystander effect in LN18 cells. Taken together, these results suggest that TNF-alpha mediates the contact-independent bystander effect in LN18 cells. The treatment with GCV and/or Sulfasalazine of tumor xenografts consisting of a mix of 98% C6 and 2% C6-TK cells shows that Sulfasalazine is also a potent adjunct to the in vivo treatment of gliomas. [less ▲]

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See detailLa tremblante du mouton influence-t-elle le système immunitaire lors d’une réponse vis-à-vis d’un antigène
Defaweux, Valérie ULg; Dorban, G.; Demonceau, C. et al

Conference (2005, November)

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See detailCharacterization of bovine and human cellular prion protein expressed in the central nervous system and in lymphoid organs.
Defaweux, Valérie ULg; Stramiello, Sara; Capellari, Sabina et al

Poster (2005, October)

Prion cell tropism varies significantly among animal species, depending on both the agent strain and host-specific factors. For example, prions show high lymphotropism in scrapie infected sheep and vCJD ... [more ▼]

Prion cell tropism varies significantly among animal species, depending on both the agent strain and host-specific factors. For example, prions show high lymphotropism in scrapie infected sheep and vCJD, but little, if any, in sCJD or BSE. In particular, the BSE strain is associate with significant PrP-res accumulation in tonsils, spleen and appendix in humans, whereas, it is largely confined to the nervous system in infected cattle. So, it appears that, at least in the case of BSE and vCJD, host properties can influence the accumulation of the infectious agent in lymphoid organs. Given that the normal cellular prion protein (PrPC), is sine qua non for PrP-res formation and the development of TSE, it appears reasonable to hypothesize that tissue-specific PrPC properties may represent one of the host factors influencing the cell tropism of the infectious agent in human or bovine. We applied a western blot analyses to compare the relative percentage of the di-, mono- and unglycosylated PrPC (the so called glycoform ratio) as well as the expression of truncated PrPC forms in tissues from the central nervous system and lymphoid structures (lymphoid follicles, lymphocytes and follicular dendritic cells) of both bovine and human. We found that PrPC glycoform ratio is significantly different between cerebellum and medulla in both bovine and human. Moreover, the expression of truncated forms of PrPC (i.e. 21 and 18 kDa PrPC) was also significantly heterogenous according to the brain region investigated. PrPC was highly glycosylated in spleen and lymphoid follicles isolated from bovine tonsils, mesenteric lymph nodes, ileal and jejunal Peyer’s patches. After deglycosylation, a novel PrPC truncated form with a relative molecular mass of about 25 kDa was detected in bovine lymphoid organs beside the typical 18 and 21 kDa forms. No difference in WB PrPC profile was seen in human lymphocytes extracted either from spleen or tonsil. Our results highlight variation in the profile expression of PrPC in peripheral and central tissues of bovine and human. Such differences may have an implication for PrPC function or may represent critical factors influencing the accumulation of the infectious agent in these areas. Supported by the EU contract QLG3-CT-2002-81030. [less ▲]

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See detailInvestigation of germinal centres in vivo and in vitro in the context of prion disease
Demonceau, C.; Defaweux, Valérie ULg; Flandroy, S. et al

Poster (2005, April)

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See detailCellular and nervous environment of mouse mesenteric lymph node germinal centres
Wenders, Frédéric ULg; Dorban, G.; Piret, Joëlle ULg et al

Conference (2005, April)

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See detailVaricella-zoster virus IE63 protein represses the basal transcription machinery by disorganizing the pre-initiation complex
Di Valentin, Emmanuel ULg; Bontems, Sébastien ULg; Habran, Lionel ULg et al

in Biological Chemistry (2005), 386(3), 255-267

Using transient transfection assays, regulation properties of varicella-zoster virus (VZV)-encoded IE63 protein were analyzed on several VZV immediate early (ORF4), early (ORF28) and late (ORF67 ... [more ▼]

Using transient transfection assays, regulation properties of varicella-zoster virus (VZV)-encoded IE63 protein were analyzed on several VZV immediate early (ORF4), early (ORF28) and late (ORF67) promoters. IE63 was shown to repress the basal activity of most of the promoters tested in epithelial (Vero) and neuronal (ND7) cells to various extents. Trans -repressing activities were also observed on heterologous viral and cellular promoters. Since a construct carrying only a TATA box sequence and a series of wild-type or mutated interleukin (IL)-8 promoters was also repressed by IE63, the role of upstream regulatory elements was ruled out. Importantly, the basal activity of a TATA-less promoter was not affected by IE63. Using a series of IE63 deletion constructs, amino acids 151-213 were shown to be essential to the transrepressing activity in Vero cells, while in ND7 cells the essential region extended to a much larger carboxy-terminal part of the protein. We also demonstrate that IE63 is capable of disrupting the transcriptional pre-initiation complex and of interacting with several general transcription factors. The central and carboxy-terminal domains of IE63 are important for these effects. Altogether, these results demonstrate that IE63 protein is a transcriptional repressor whose activity is directed towards general transcription factors. [less ▲]

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See detailFollicular dendritic cells innervation within spleen of five mouse strains with different incubation periods after intraperitoneal BSE inoculation.
Demonceau, C.; Marshall, A.; Sales, J. et al

Poster (2005, February)

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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 detailInduction of Apoptosis in Human Promyelocytic Leukemia Cells by a Natural Trachylobane Diterpene
Block, Sébastien; Gerkens, Pascal; Peulen, Olivier ULg et al

in Anticancer Research (2005), 25(1A), 363-368

Background: Trachylobane diterpenes are secondary metabolites quite rare in nature and their bioactivities are poorly known. Recently we have described the cytotoxic activity of ent- trachyloban-3‚-ol ... [more ▼]

Background: Trachylobane diterpenes are secondary metabolites quite rare in nature and their bioactivities are poorly known. Recently we have described the cytotoxic activity of ent- trachyloban-3‚-ol isolated from the leaves of Croton zambesicus, a plant used in African folk medicine. Materials and Methods: Cell viability on several cell lines, cell morphology, DNA laddering, annexin V and caspase-3 activation experiments were undertaken in order to analyse the cytotoxicty of trachylobane diterpene and to determine if this compound is able to induce apoptosis. Results: ent-trachyloban-3‚-ol exerts a dose-dependent cytotoxic effect and which varies between cell lines. Induction of apoptosis in HL-60 cells could be detected at a concentration of 50 ÌM after 24-h treatment. Conclusion: We show here, for the first time, that a trachylobane diterpene is able to induce apoptosis in human promyelocytic leukemia cells via caspase-3 activation in a concentration-dependent manner. [less ▲]

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