Search PubMed⌕ Search

Biomedical subjects

E Heinen

Publications and source records attributed to E Heinen.

At least 55 records · Page 3Linked to original sources
PubMed1995

Safety aspects in the development of an infectious bovine rhinotracheitis marker vaccine.

Clinical trials in cattle demonstrated that the IBR marker modified live vaccine based on the gE-deleted IBR strain Difivac is immunogenic and safe for bovines of all ages. Potential effects of the vaccine virus have also been tested in swine and sheep and proved safe for these species as well. For evaluation of other environmental aspects, the spread of the vaccine virus after immunisation was investigated. The data indicated that the vaccine virus may be shed by immunised animals but that it has a limited ability to pass from animal to animal. It was also demonstrated that the attenuated Difivac strain does not revert to virulence during calf passage. Preliminary results indicated that the gE-deleted vaccine virus of the IBR marker vaccine cannot be reactivated after dexamethasone treatment, an important advantage for a vaccine strain. Furthermore, immunisation with the Difivac strain reduced the ability of a superinfecting challenge virus to become latent or to be reactivated.

Animals↗
PubMed1995

[Immunohistochemical determination of Chlamydia psittaci/pecorum and C.trachomatis in the piglet gut].

The jejunum, ileum, caecum and colon of 200 piglets were investigated immunohistochemically for the presence of Chlamydia psittaci and C. trachomatis using a vitelline IgY. Positive samples were later labelled using a commercial C. trachomatis polyclonal antiserum. Chlamydia were present in 33 (16.4%) of the animals, and 30 out of 33 were labelled by C. trachomatis polyclonal antiserum. Inclusions occurred predominantly (67%) in the large intestine. The serological results (CFT, ELISA) did not correlate well with immunohistochemical labelling in the gut. The incidence of Chlamydia rose from 6.9% in animals up to 4 weeks, to 41.8% in those over 4 weeks of age. A correlation between chlamydia and enteric disease was not obvious. Besides chlamydia, most of the diseased animals harboured other additional agents. In conclusion, intestinal chlamydiae in piglets, predominantly C. trachomatis, exist in Switzerland, although their pathogenic potential seems to be low.

Animals↗
PubMed1995

[Follicular dendritic cells: phenotype, origin and functions].

Follicular dendritic cells (FDC) are only located in lymph node follicles and particularly developed in the light zones of the germinal centers. FDC differ on important points from the classical dendritic cells presenting antigens to T cells. They are long-lived and derived from local mesenchymal cells. Their complex cytoplasmic extensions, covered with dendrites, are intermingled in a network which surrounds germinal B and T cells. On their surface, receptors fix immune complexes without endocytosis and adhesion molecules ensure close contacts to the lymphoid cells. FDC influence the migration, activation, proliferation, survival and differentiation of B cells into memory cells and probably act also on the germinal center T cells.

Acquired Immunodeficiency Syndrome↗
PubMed1994

AGM-1470, a potent angiogenesis inhibitor, prevents the entry of normal but not transformed endothelial cells into the G1 phase of the cell cycle.

AGM-1470 is a potent angiogenesis inhibitor that is very effective in inhibiting endothelial cell proliferation in both in vitro and in vivo models and that prevents tumor growth in vivo. Although this molecule appears to be a most promising anticancer drug, its mechanism of action has not yet been elucidated. In this study, we examined the effects of AGM-1470 on the cell cycle of normal and transformed endothelial cells. We showed that AGM-1470, at picomolar concentrations, specifically inhibits the proliferation of both bovine aortic endothelial cells and human umbilical vein endothelial cells. AGM-1470 was ineffective in significantly inhibiting the proliferation of Ea.hy926 cells, a hybrid cell line obtained by the fusion of human umbilical vein endothelial cells with a human carcinoma cell line, or cEnd.1 cells, a polyoma middle T oncogene-transformed endothelioma cell line derived from mouse embryo. Using a double labeling technique with anti-Ki67 antibodies and propidium iodide, we demonstrated, with flow cytometry analysis, that AGM-1470 specifically prevents the entry of endothelial cells into the G1 phase of the cell cycle. We also showed that AGM-1470 was ineffective in inhibiting endothelial cell migration toward laminin or capillary-like tube formation inside a type I collagen matrix induced by phorbol esters. Our data strongly suggest that AGM-1470 is a molecule that specifically inhibits a cell cycle control pathway active in normal cells but which could be bypassed or altered in transformed cells.

Animals↗
PubMed1994

Moabs MAS516 and 5B5, two fibroblast markers, recognize human follicular dendritic cells.

Follicular dendritic cells (FDC) are only located within follicles of secondary lymphoid tissues. The origin of this peculiar cell type is not clearly defined. To contribute to this study, we applied two monoclonal antibodies (MAS516 and 5B5) considered as specific for fibroblasts to tonsil cryosections and to isolated follicular dendritic cells. On the basis of an enzyme cocktail digestion of human tonsils and a fractionation procedure on albumin gradients, FDC can be prepared in the form of cell aggregates with associated lymphoid cells. MAS516 reacts with surface membrane molecules expressed by human fibroblasts, tissue macrophages and peripheral blood monocytes. With immunoperoxidase assays on tonsil cryosections connective tissue cells and macrophages are stained. Inside germinal centres, heavy labelling of the light zone was found. The MAS516 staining pattern is very similar to that of specific FDC markers DRC-1 or BU10. All isolated FDC reacted with MAS516 antibody. 5B5, considered as a typical fibroblast marker, reacts with human prolyl-4-hydroxylase which is an intracellular enzyme related to collagen biosynthesis. In cryosections, interfollicular and capsular areas showed 5B5 positive connective tissue fibroblasts. In germinal centres, some cells presenting features of FDC were 5B5 positive. After cell separation, 25%-50% of the isolated FDC were labelled with this antibody. This positivity of some FDC for 5B5 antibody may support the idea of their fibroblastic origin. The combination of observations realized in situ and after cell purification ensured an unequivocal recognition and identification of FDC.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1994

Follicular dendritic cells: whose children?

At the recent Germinal Centre Conference in Spa*, over 200 immunologists gathered to study the fate of lymph follicles, B- and T-cell selection, cell migration, accessory cells, and pathological conditions such as lymphoproliferative diseases and AIDS. Here, Ernst Heinen and Alain Bosseloir report on this fascinating field.

Animals↗
PubMed1992

Emperipolesis of lymphoid cells by human follicular dendritic cells in vitro.

Isolated follicular dendritic cells (FDCs) showed true and pseudoemperipolesis of fresh tonsillar lymphocytes, even after long-term (50-day) cultivation. Emperipolesis by FDCs was not restricted by allotype specificity, nor was it inhibited by the addition of antibodies against MHC-I & II antigens. Follicular dendritic cells predominantly engulfed B-cells; monocytes and macrophages were not found between FDC cytoplasmic extensions. When highly purified T-cell populations were added to FDC cultures emperipolesis of T-cells occurred, particularly those of the CD4-positive phenotype. Mitoses appeared within 6 h in the emperipolesed lymphocytes and, after an additional 18 h, some lymphocytes exhibited apoptosis.

Antigens, Differentiation↗
PubMed1990

Isolation and long-term cultivation of human tonsil follicular dendritic cells.

Highly purified follicular dendritic cells (FDC) were isolated from human tonsils and cultivated for up to 150 days. The cell separation method employed produced pure aggregates (FDC-clusters) composed of FDC and germinal center lymphoid cells, useful for the analysis of the relationship between these two cell types and of the behavior of FDC in culture. During the first few days of culture, lymphoid cells located between FDC extensions survived better than those which were free or partly covered by FDC. After 6 days, the lymphoid population degenerated and only the FDC survived. The unique antigenic pattern of FDC (positive for HLA-DR. DRC-1, CD14b, CD21, CD23, CD35) disappeared within a few days of culture. Recombinant interferon-gamma exerted a positive effect either on retaining HLA-DR expression or on the reexpression of these antigens by FDC. HLA-ABC antigens were traced until the 10th day and desmosomal junctions until the 14th day. Subsequently, FDC presented peculiar features, including oval and rhomboid shapes, one to ten nuclei, fine amoeboid extensions, stress fibers and a radical dense zone in their cytoplasm. FDC possessed actin, tubulin and vimentin, but neither desmin nor cytokeratin. After 40 days of culture, FDC enlarged and were covered with abundant membrane extensions. Even when kept as long as 150 days in vitro. FDC did not proliferate in any of the culture conditions employed.

Actins↗
PubMed1989

Localization of interleukin 6 mRNA in human tonsils by in situ hybridization.

We have investigated which areas produce interleukin 6 (IL 6) in human tonsils. This growth factor is required for the terminal differentiation of B lymphocytes into plasmocytes. Using 35S-labeled IL 6 cDNA we demonstrated IL 6 gene expression over various areas of the tonsils, with consistent exception of the follicles, by in situ hybridization. It is, therefore, proposed that B cells are stimulated during their migration out of the follicles.

B-Lymphocytes↗
PubMed1989

Cytokines produced in lymph follicles.

The events occurring inside lymph follicles during a germinal center reaction are poorly understood. Using B and T lymphoid cell populations prepared from human tonsillar lymph follicles, and enriched or not in macrophages or in follicular dendritic cells, we examined the production of cytokines by these cells in vitro. Interleukin 6 (IL-6) and tumor necrosis factor (TNF) were found in the supernatants of cultures stimulated with phytohemagglutinin or pokeweed mitogen. IL-1 beta was occasionally detected; its secretion apparently depends on the origin of the tonsils, the stimulation, and the cell populations. IFN-gamma and IL-2 were not produced in significant amounts by these lymph follicle cells. IL-4 was only found in very low concentrations in the supernatant of the different cell cultures. The cell populations containing follicular dendritic cells produced more IL-6 and TNF than the others, especially than those composed of only B and T cells.

Adenoids↗