Search results for "Cell Fusion"
showing 10 items of 30 documents
PKSP-dependent reduction of phagolysosome fusion and intracellular kill of Aspergillus fumigatus conidia by human monocyte-derived macrophages.
2002
Summary Previously, we described the isolation of an Aspergillus fumigatus mutant producing non-pigmented conidia, as a result of a defective polyketide synthase gene, pksP (polyketide synthase involved in pigment biosynthesis). The virulence of the pksP mutant was attenuated in a murine animal infection model and its conidia showed enhanced susceptibility towards damage by monocytes in vitro. Because macrophage-mediated killing is critical for host resistance to aspergillosis, the interaction of both grey-green wild-type conidia and white pksP mutant conidia with human monocyte-derived macrophages (MDM) was studied with respect to intracellular processing of ingested conidia. After phagocy…
Hepatocyte cell lines: their use, scope and limitations in drug metabolism studies.
2006
Gaining knowledge on the metabolism of a drug, the enzymes involved and its inhibition or induction potential is a necessary step in pharmaceutical development of new compounds. Primary human hepatocytes are considered a cellular model of reference, as they express the majority of drug-metabolising enzymes, respond to enzyme inducers and are capable of generating in vitro a metabolic profile similar to what is found in vivo. However, hepatocytes show phenotypic instability and have a restricted accessibility. Different alternatives have been explored in the past recent years to overcome the limitations of primary hepatocytes. These include immortalisation of adult or fetal human hepatic cel…
The ultrastructure of multinucleate giant cells
2002
Abstract A survey of the available ultrastructural data on physiologically and pathologically occurring and virally-induced multinucleate giant cells (MNGCs) is presented. Emphasis is initially placed upon the bone osteoclast, the skeletal muscle myotube and the placental syncytiotrophoblast. The widespread occurence of MNGCs in a range of pathological situations is discussed, with emphasis upon the broad involvement of the macrophage in inflammatory responses. Many viruses produce cell fusion in vivo and in vitro when cell cultures are infected. Several examples are given. A clear distinction is drawn between viral fusion from “without” and viral fusion from “within” the cell. The cytopath…
Establishment of an HIV cell-cell fusion assay by using two genetically modified HeLa cell lines and reporter gene.
2003
Infection of human cells with the human immunodeficiency virus type I (HIV-1) can be mimicked by a fusion process between cells expressing the HIV envelope protein (Env) and cells expressing both human CD4 together with the appropriate human chemokine receptors. In this study, a T-tropic HIV cell-cell fusion assay was established that utilized CD4, human CXCR4 and HIV NL4-3 gp160 as fusion components and a T7 polymerase-activated luciferase as a reporter system. The HeLa T4 cells used, expressed CD4 and CXCR4, and the applied HeLa KS386 cells expressed HIV NL4-3 gp160. By combining HeLa T4 cells with HeLa KS386 cells, an approximately about 100- to 300-fold increase in luciferase activity c…
Evidence for a multistep mechanism for cell-cell fusion by herpes simplex virus with mutations in the syn 3 locus using heparin derivatives during fu…
1994
Addition of heparin-Na+ as well as related substances of high and intermediate MW (Arteparon and polyanion SP54) 3 h after infection inhibit fusion from within (FFWI) induced by HSV strains with mutations in the syn 3 locus only. The concentration of heparin-Na+ required to inhibit FFWI is 10-fold higher (1 mg/ml) than that needed to inhibit adsorption. Instead of fusion, cell rounding is observed. The effect is readily reversible. A low MW heparin disaccharide is ineffective. Neomycin, at a concentration of 8 mM, inhibits FFWI induced by all HSV-1 but not HSV-2 strains, whereas adsorption is inhibited at 3 mM. We conclude from our observations that cell-cell fusion (FFWI) induced by syn 3 …
Heart infarct in NOD-SCID mice: therapeutic vasculogenesis by transplantation of human CD34+ cells and low dose CD34+KDR+ cells
2004
Hematopoietic (Hem) and endothelial (End) lineages derive from a common progenitor cell, the hemangioblast: specifically, the human cord blood (CB) CD34+KDR+ cell fraction comprises primitive Hem and End cells, as well as hemangioblasts. In humans, the potential therapeutic role of Hem and End progenitors in ischemic heart disease is subject to intense investigation. Particularly, the contribution of these cells to angiogenesis and cardiomyogenesis in myocardial ischemia is not well established. In our studies, we induced myocardial infarct (MI) in the immunocompromised NOD-SCID mouse model, and monitored the effects of myocardial transplantation of human CB CD34+ cells on cardiac function.…
Uniform response of c-raf expression to differentiation induction and inhibition of proliferation in a rat rhabdomyosarcoma cell line
1990
The clonal rat rhabdomyosarcoma cell line BA-HAN-1C is composed of proliferating mononuclear cells, some of which spontaneously fuse to terminally differentiated myotube-like giant cells. Both the induction of differentiation by retinoic acid (RA) and by sodium butyrate (NaBut), as well as the inhibition of proliferation by fetal calf serum (FCS)-depleted medium uniformly resulted in the same effects. There was a significant (p less than 0.001) inhibition of proliferation and induction of cellular differentiation, as evidenced by a significant (p less than 0.05) increase in creatine kinase activity. Furthermore, after exposure to RA-supplemented or FCS-depleted medium, a significant (p less…
Contracting striated muscle fibres differentiated from primary rat pituitary cultures.
1982
Whole pituitaries or adenohypophyses alone of adult female Wistar/ Furth rats were dissociated into single cells by means of two different enzymic disintegration methods. The single-cell suspension was then seeded out and cultured for up to 8 months in tissue culture dishes with untreated and polylysine coated surfaces. The cells were cultured in different sera (horse serum, newborn-calf serum, fetal-calf serum, mixtures of horse and newborn-calf serum, and isogenic rat serum) and also in a serum-free, hormone-supplemented medium. When the cells were cultured in medium containing horse serum (15 %) plus fetal-calf serum (3%) on polylysine-treated surfaces, cell fusion and the development of…
Microtubules and microfilaments in HSV-Infected rabbit-kidney cells.
1981
In rabbit kidney cells infected with strains of Herpes simplex virus producing either cell-rounding or polycaryocytosis. Vinblastine induced paracrystals. This could be shown by phase-contrast- and electron-microscopy. Infections were done under one-step-growth conditions or at low MOI. 90 per cent noninfected cells contained stress fibers as detected by Servablue R250-staining. Shortly after recruitment into polycaryocytes, stress fibres of normal length appearing in criss-cross arrangement can be seen in the periphery of these cells. Later they polymerize to very long fibers and finally they are partially destroyed. The time of destruction depends on the MOI employed. By using Actinomycin…
Single amino acid substitutions in the glycoprotein B carboxy terminus influence the fusion from without property of herpes simplex virus type 1.
1995
Syncytial mutations of herpes simplex virus type 1 (HSV-1) strains ANG, ANG path, HFEM, tsB5 and HSZP cause extensive cell fusion and were mapped to the cytoplasmic domain of glycoprotein B (gB), within the syn 3 locus. These strains are so far the only ones which show the phenotype ‘fusion from without’ (FFWO): 60 min after infection with high m.o.i., cells in a tissue culture are fused without transcription and translation of the viral genome. In this report we detected, using the recombinants 27/III and K-7, that an amino acid exchange from Ala to Val at aa position 854 of gB is the main determinant for FFWO activity of strains ANG, ANG path and recombinant K-7. The transfer of this muta…