References of "Heinen, Ernst"
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See detailImmunohistochemical study on cultured FDC-C enriched lymphoid cell populations.
Tsunoda, R.; Cormann, N.; Heinen, Ernst ULg et al

in Advances in Experimental Medicine and Biology (1988), 237

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See detailIsolation of follicular dendritic cells from human tonsils and adenoids. In vitro culture.
Cormann, N.; Heinen, Ernst ULg; Kinet-Denoel, C. et al

in Advances in Experimental Medicine and Biology (1988), 237

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See detailInteractions between follicular dendritic cells and lymphoid cells.
Heinen, Ernst ULg; Braun, M.; Louis, Edouard ULg et al

in Advances in Experimental Medicine and Biology (1988), 237

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See detailInfluence of immunoglobulin isotypes and lymphoid cell phenotype on the transfer of immune complexes to follicular dendritic cells.
Braun, M.; Heinen, Ernst ULg; Cormann, N. et al

in Cellular Immunology (1987), 107(1), 99-106

Follicular dendritic cells (FDC) are located only inside lymph follicles and are characterized mainly by their capacity to retain high amounts of immune complexes by their Fc or C3b receptors. In this ... [more ▼]

Follicular dendritic cells (FDC) are located only inside lymph follicles and are characterized mainly by their capacity to retain high amounts of immune complexes by their Fc or C3b receptors. In this work, we examine the influence of immunoglobulin isotypes and the subset of lymphoid cells (B or T) upon the transfer of immune complexes from lymphocytes to FDC. FDC isolated from mice lymph nodes by enzymatic digestion are able to fix, through Fc receptors, gold-labeled immune complexes presented by lymphoid cells. As demonstrated by electron microscopy, this transfer requires the establishment of close contacts between both cell types. Using different cell selection techniques we show that B lymphoid cells take up immune complexes more efficiently than do T lymphoid cells and transfer a larger number of them to FDC. This transfer mechanism is dependent on the immunoglobulin isotype: immune complexes constituted of IgG2a, IgG2b, and IgG1 isotypes are better transferred to FDC than those constituted of IgG3 and IgM. [less ▲]

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See detailMicroenvironments for B cell production and stimulation
Heinen, Ernst ULg; Tsunoda, R.

in Immunology Today (1987), 8

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See detailEffects of cis-diamminedichloroplatinum (II) loaded liposomes on mouse Ehrlich tumor cells.
De Pauw-Gillet, Marie-Claire ULg; Heinen, Ernst ULg; Weber, Géraldine ULg et al

in European Journal of Cancer & Clinical Oncology (1986), 22(10), 1139-47

Cis-diamminedichloroplatinum II (cisplatin) heavily or lightly loaded (fluid, solid, negatively charged or neutral) liposomes were prepared. Cisplatin release from liposomes was observed only after long ... [more ▼]

Cis-diamminedichloroplatinum II (cisplatin) heavily or lightly loaded (fluid, solid, negatively charged or neutral) liposomes were prepared. Cisplatin release from liposomes was observed only after long dialysis times or after liver lysosomal enzymatic disintegration in solution. Mouse Ehrlich tumor cells (ELT) cultured in vitro were treated with cisplatin, liposomes or cisplatin loaded liposomes, and the effects on the mitotic activity, the DNA content and the ultrastructure were compared. Cisplatin (1-10 micrograms/ml) had an antimitotic activity and modified the DNA content in ELT cells. Ribosome aggregation, perichromatin or interchromatin granule accumulation, and chromatin condensation or some degree of dispersion could be observed. Negatively charged fluid liposomes had an antimitotic activity and modified the DNA content in ELT cells at lower concentrations (0.3 mumoles/ml) than in the case of neutral fluid liposomes (1.5 mumoles/ml). Negatively charged solid liposomes were not toxic at these concentrations. Ultrastructural analysis of ELT cells treated in vitro with negatively charged fluid liposomes revealed their extracellular adsorption and their disintegration in phagolysosomes. A fusion between liposomes and the plasma membrane was not definitely demonstrated. Cisplatin loaded liposomes also had an antimitotic activity and modified the DNA content in ELT cells. These effects were similar to or more pronounced than those induced by free cisplatin. Ultrastructural analysis revealed some kind of electron dense material in phagolysosomes which was never observed after the treatment with free cisplatin or liposomes alone. Effects on nucleic acids were rarely observed. [less ▲]

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See detailIsolation of follicular dendritic cells from human tonsils and adenoids. V. Effect on lymphocyte proliferation and differentiation.
Cormann, N.; Lesage, F.; Heinen, Ernst ULg et al

in Immunology Letters (1986), 14(1), 29-35

Follicular dendritic cells (FDC) are located only in lymph follicles and are characterized by their capacity to retain high amounts of immune complexes on their plasma membranes. As their functions in ... [more ▼]

Follicular dendritic cells (FDC) are located only in lymph follicles and are characterized by their capacity to retain high amounts of immune complexes on their plasma membranes. As their functions in germinal centres are unknown, we isolated them from human tonsils and cultured them with autologous lymphoid cells. Cultures of lymphoid cells alone or with added macrophages were used as controls. Lymphoid cells incorporated tritiated thymidine only when FDC and lectins were added; this could be shown after several periods of time. However, the Ig secretion by lymphoid cell populations was inhibited by FDC after several days in vitro. In contrast, the supernatants of lymphocytes cultured alone or with macrophages only for the same periods of time contained increasing amounts of immunoglobulins. This inhibitory effect of FDC on immunoglobulin production was observed for all considered isotypes. Our data suggest that FDC stimulate lymphoid cell proliferation but reduce B-cell differentiation. This is the first accessory cell activity definitely shown for FDC in cultures. [less ▲]

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See detailRetention of immune complexes by murine lymph node or spleen follicular dendritic cells. Role of antibody isotype.
Heinen, Ernst ULg; Coulie, P.; Van Snick, J. et al

in Scandinavian Journal of Immunology (1986), 24(3), 327-34

Using monoclonal anti-trinitrophenyl (TNP) antibodies complexed to TNP-myoglobin-coated gold particles, we analysed at the ultrastructural level the retention by follicular dendritic cells (FDC) of immune ... [more ▼]

Using monoclonal anti-trinitrophenyl (TNP) antibodies complexed to TNP-myoglobin-coated gold particles, we analysed at the ultrastructural level the retention by follicular dendritic cells (FDC) of immune complexes containing various antibody isotypes. Gold-labelled immune complexes were injected subcutaneously or intravenously into naive mice and, after 24 h, germinal centres of draining lymph nodes or spleen were examined by electron microscopy. FDC generally retained complexes containing IgG2a and IgG2b better than those formed with IgG1 or IgG3. IgM was rarely retained. FDC isolated from lymph nodes or spleens were incubated in vitro with gold-labelled complexes in a serum-free medium. IgG2a and IgG2b complexes were also retained in vitro in large quantities by FDC; IgG1 and IgG3 complexes were retained in smaller quantities or in highly variable quantities compared with IgG2; IgM complexes were rarely seen on FDC. There was no difference between FDC isolated from lymph nodes or from spleen with respect to the Ig isotypes required for Fc-mediated retention of immune complexes. [less ▲]

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See detailLipopolysaccharide suppresses immune complex retention by follicular dendritic cells without cytological alterations.
Heinen, Ernst ULg; Cormann, N.; Kinet-Denoel, C. et al

in Immunology Letters (1986), 13(6), 323-7

Follicular dendritic cells (FDC) are peculiar cells only located inside lymph follicles and which may be characterized by complex dendritic evaginations retaining high quantities of immune complexes by Fc ... [more ▼]

Follicular dendritic cells (FDC) are peculiar cells only located inside lymph follicles and which may be characterized by complex dendritic evaginations retaining high quantities of immune complexes by Fc and C3b receptors. After lipopolysaccharide (LPS) injection in mice the retention of gold-labelled immune complexes was abolished in draining lymph nodes. In order to examine the possibility that the transport of immune complexes to lymph follicles was impaired, we isolated FDC from lymph nodes and incubated them in presence of gold-labelled complexes: no or strongly reduced retention was then observed at the ultrastructural level. This LPS-induced impairment of immune complex fixation by FDC is not due to morphological alteration to the cells but to the inhibition of their Fc and C3b receptors. Further, LPS induces changes in the composition of the lymphocyte population in lymph follicles as higher numbers of blast cells and plasmocytes are observed after treatment. [less ▲]

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See detailIsolation of follicular dendritic cells from human tonsils and adenoids. VI. Analysis of prostaglandin secretion.
Heinen, Ernst ULg; Cormann, N.; Braun, M. et al

in Annales de l'Institut Pasteur. Immunologie (1986), 137D(3), 369-82

Follicular dendritic cells (FDC) are able to fix high amounts of immune complexes by C3b or Fc receptors without endocytosis and for long periods of time. In order to determine the function of this ... [more ▼]

Follicular dendritic cells (FDC) are able to fix high amounts of immune complexes by C3b or Fc receptors without endocytosis and for long periods of time. In order to determine the function of this retention, we analysed the secretion of prostaglandin E2 (PGE2) by FDC in vitro; indeed, it is well-known that immune complex fixation on cells may induce PGE2 production. FDC were isolated by enzymic digestion of lymph follicles dissected under the biomicroscope from human tonsils or adenoids. Isolated FDC appeared as spherical clusters where they enveloped lymphoid cells with their cytoplasmic extensions. Tests were performed in synthetic culture media or in media supplemented with foetal calf serum. PGE2 production in FDC suspensions was compared to that of lymphocyte or macrophage-enriched populations prepared from the same human tonsils. In all experimental conditions, FDC and macrophage-enriched cell populations produced high levels of PGE2, inversely to lymphoid cell populations. This secretion was inhibited by indomethacin. At the ultrastructural level, we also showed that 3H-arachidonic acid was metabolized in cell membranes of all three cell types. The PGE2 produced in the culture media, according to our experimental conditions, do not influence cell proliferation, as assessed by 3H-thymidine incorporation tests on phytohaemagglutinin-stimulated lymphocytes. [less ▲]

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See detailTransfer of immune complexes from lymphocytes to follicular dendritic cells.
Heinen, Ernst ULg; Braun, M.; Coulie, P. G. et al

in European Journal of Immunology (1986), 16(2), 167-72

Antigens in the form of immune complexes are retained on the membranes of follicular dendritic cells (FDC) for long periods of time. To examine how immune complexes reach germinal centers, where FDC are ... [more ▼]

Antigens in the form of immune complexes are retained on the membranes of follicular dendritic cells (FDC) for long periods of time. To examine how immune complexes reach germinal centers, where FDC are located, we injected mice with anti-2,4-dinitrophenyl (DNP) antibodies complexed to DNP-myoglobin-coated gold particles. The distribution of the particles in spleens or draining lymph nodes was then determined with the electron microscope. The vast majority of the particles were cell bound. Shortly after injection they were phagocytized by macrophages or fixed on lymphocytes. The latter were found even in the corona of lymph follicles but not in germinal centers. Already 30 min after injection, FDC in contact with the corona were faintly positive but were negative in the center. FDC precursor cells were occasionally observed but in too small a number to account for the transport of immune complexes to the germinal centers. Twenty-four hours after injection colloidal gold particles were found in phagolysosomes of macrophages or on cytoplasmic extensions of FDC in all parts of the germinal centers. Experiments performed on isolated FDC showed that they are not only able to take up free immune complexes but are also able to adsorb immune complexes from pulsed lymphocytes. These results strengthen the idea that lymphoid cells binding immune complexes by their Fc receptors may transport these complexes inside germinal centers. [less ▲]

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See detailInfluence de la cellule folliculaire dendritique sur la survie des lymphocytes in vitro.
Cormann, N.; Heinen, Ernst ULg; Kinet-Denoel, C. et al

in Comptes Rendus des Séances de la Société de Biologie et de ses Filiales (1986), 180(2), 218-23

To study the role of follicular dendritic cells (FDC) in germinal centers, we tried to keep them alive in vitro by culturing entire lymphoid follicles. Ultrastructural studies of those cultures in ... [more ▼]

To study the role of follicular dendritic cells (FDC) in germinal centers, we tried to keep them alive in vitro by culturing entire lymphoid follicles. Ultrastructural studies of those cultures in different conditions of culture technique, medium and temperature have been made. In any considered conditions living FDC were not found in the cultures after the 7th day. But during that period, only lymphocytes in close contact with the cytoplasmic processes of FDC survived. FDC seem thus to exert a positive action on lymphocyte survival in vitro. Moreover, FDC and lymphocytes appeared associated in situ in clusters similar to those obtained after isolation of FDC (Lilet-Leclercq et al., J. Immunol. Meth., 1984, 59, 235). [less ▲]

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See detailIsolation, characterization and possible functions of follicular dendritic cells from tonsils and adenoids.
Kinet-Denoël, C.; Heinen, Ernst ULg; Simar, L.

in Cell sparation: methods and selected applications (1986)

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See detailMouse lymph node follicular dendritic cells: quantitative analysis and isolation.
Heinen, Ernst ULg; Kinet-Denoel, C.; Radoux, Dominique ULg et al

in Advances in Experimental Medicine and Biology (1985), 186

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See detailRetention of immune complexes by Fc receptors on mouse follicular dendritic cells.
Radoux, D.; Kinet-Denoel, C.; Heinen, Ernst ULg et al

in Scandinavian Journal of Immunology (1985), 21(4), 345-53

Follicular dendritic cells (FDC) are located inside lymph follicles and are mainly characterized by their capacity to retain antigens. We investigated this aspect in mice lymph nodes by using bovine serum ... [more ▼]

Follicular dendritic cells (FDC) are located inside lymph follicles and are mainly characterized by their capacity to retain antigens. We investigated this aspect in mice lymph nodes by using bovine serum albumin (BSA) labelled with 5-nm colloidal gold particles and homologous anti-BSA antibodies bound to 20-nm gold particles. Gold-labelled BSA injected alone in non-immunized mice was only rarely found in FDC cytoplasmic interdigitations. Injected in the form of immune complexes, it was retained by FDC. Antigen-free anti-BSA antibodies injected under similar conditions as immune complexes were always found in draining lymph nodes in the same locations as BSA-anti-BSA immune complexes. F(ab')2 from mouse immunoglobulins linked to colloidal gold particles were very rarely found between the FDC extensions, whereas it was intensely phagocytosed by macrophages. Our study permitted precise ultrastructural localization between FDC cytoplasmic extensions or inside macrophages and other cells of the lymph nodes, but it also pointed out that homologous antibodies linked to colloidal gold particles might be retained by FDC in the absence of antigens. These observations, carried out with colloidal gold, were checked by using 125I-labelled anti-BSA antibodies. Complement activation determinations of gold-labelled antibodies or immune complexes showed that antibodies or immune complexes fixed on colloidal gold particles do not activate the complement. This observation enabled us to conclude that Fc receptors play a significant part in the retention of gold-labelled antibodies or immune complexes by FDC of lymph nodes. [less ▲]

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See detailAntigen/antibody retention by follicular dendritic cells (FDC).
Radoux, D.; Heinen, Ernst ULg; Kinet-Denoel, C. et al

in Advances in Experimental Medicine and Biology (1985), 186

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See detailFollicular dendritic cells isolated from human tonsils.
Kinet-Denoel, C.; Heinen, Ernst ULg; Radoux, D. et al

in Advances in Experimental Medicine and Biology (1985), 186

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See detailIsolation of follicular dendritic cells from human tonsils and adenoids. III. Analysis of their Fc receptors.
Heinen, Ernst ULg; Radoux, D.; Kinet-Denoel, C. et al

in Immunology (1985), 54(4), 777-84

Follicular dendritic cells (FDC), isolated from human tonsils or adenoids, were tested for their capacity to retain monomeric, aggregated or antigen-bound human antibodies in the absence of serum. FDC ... [more ▼]

Follicular dendritic cells (FDC), isolated from human tonsils or adenoids, were tested for their capacity to retain monomeric, aggregated or antigen-bound human antibodies in the absence of serum. FDC retain fluorescein-labelled heat-aggregated human immunoglobulins, but not monomeric ones nor fluorescein-labelled F(ab')2 in monomeric or aggregated form. Ultrastructural observations showed that colloidal gold-labelled monomeric, or antigen-bound, antibodies directed against tetanus toxoid are retained by dendrites and membrane infoldings of FDC but are never located in cytoplasmic vesicles. This retention was inhibited by incubating FDC with unlabelled aggregated or antigen-bound antibodies. When gold-labelled anti-tetanus toxoid antibodies were incubated in the presence of protein-A before the contact with FDC, a strong reduction of their retention occurred. This further suggested the presence of Fc receptors on isolated tonsillar FDC. Endocytosis was not observed in isolated FDC, even after prolonged incubation in presence of labelled immune complexes: their Fc receptors are, thus, not related to a phagocytic activity as they are in macrophages. Simultaneous ultrastructural labelling of Fc and C3b receptors with colloidal gold particles of different sizes did not reveal any clear relations between these two receptors on the surface of FDC. [less ▲]

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See detail5-Nucleotidase activity in isolated follicular dendritic cells.
Heinen, Ernst ULg; Kinet-Denoel, C.; Simar, L. J.

in Immunology Letters (1985), 9(2-3), 75-80

Follicular dendritic cells isolated from mouse lymph nodes were incubated in the presence of AMP to test 5-nucleotidase (5-Nase) activity. Ultrastructural observations showed the presence of 5-Nase on ... [more ▼]

Follicular dendritic cells isolated from mouse lymph nodes were incubated in the presence of AMP to test 5-nucleotidase (5-Nase) activity. Ultrastructural observations showed the presence of 5-Nase on external membranes but also some activity inside the nucleus. 5-Nase was found associated to Fc receptors labelled with homologous immunoglobulins fixed on colloidal gold particles. Lymphocytes and macrophages, found in association with the follicular dendritic cells, were either 5-Nase positive or negative. The hypothetical roles played by 5-Nase in germinal centers are discussed. [less ▲]

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See detailPrecise localization of antigens on follicular dendritic cells.
Radoux, D.; Heinen, Ernst ULg; Kinet-Denoel, C. et al

in Cell & Tissue Research (1984), 235(2), 267-74

Horse-spleen ferritin or bovine serum albumin conjugated to colloidal gold (BSA-gold) were injected subcutaneously in preimmunized mice. In draining lymph nodes both antigens were located in macrophages ... [more ▼]

Horse-spleen ferritin or bovine serum albumin conjugated to colloidal gold (BSA-gold) were injected subcutaneously in preimmunized mice. In draining lymph nodes both antigens were located in macrophages or between the cytoplasmic processes of follicular dendritic cells (FDC). Some of the antigens remained trapped on FDC until day 31 after injection. Simultaneous injection of both antigens showed that they were located between the infoldings of the same FDC. These cells are thus able to retain at least two different antigens on their surface. The peculiar arrangement of ferritin between the cytoplasmic infoldings suggests that this antigen is fixed on both cell membranes by specific antibodies. The trapped immune complexes could thus stabilize the FDC membrane system. The antigen retention requires the presence of specific antibodies since BSA-gold or ferritin injected without preimmunization were not found between FDC processes. Nonantigenic materials, such as colloidal gold or carbon particles, are not trapped by FDC, except when injected in large amounts. The antigens were trapped on the surface of FDC, however unfrequently in close contact with lymphocytes. FDC might protect lymphocytes against an excess of immune complexes and act as regulators of contacts between lymphocytes and immune complexes. [less ▲]

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