Search results for "Cellular differentiation"
showing 10 items of 482 documents
The transcription factor Interferon Regulatory Factor 4 is required for the generation of protective effector CD8 + T cells
2013
Robust cytotoxic CD8 + T-cell response is important for immunity to intracellular pathogens. Here, we show that the transcription factor IFN Regulatory Factor 4 (IRF4) is crucial for the protective CD8 + T-cell response to the intracellular bacterium Listeria monocytogenes . IRF4-deficient ( Irf4 −/− ) mice could not clear L. monocytogenes infection and generated decreased numbers of L. monocytogenes -specific CD8 + T cells with impaired effector phenotype and function. Transfer of wild-type CD8 + T cells into Irf4 −/− mice improved bacterial clearance, suggesting an intrinsic defect of CD8 + T cells in Irf4 −/− mice. Following transfer into wild-type recipients, Irf4 −/− CD8 + T cells bec…
Rapid Differentiation of a Rare Subset of Adult Human Lin−CD34−CD38− Cells Stimulated by Multiple Growth Factors In Vitro
1999
Recently, several reports of lineage-negative (lin(-)) CD34(-) cells with in vivo hematopoietic activity have focused interest on the properties and growth factor response characteristics of these cells. We have now identified a combination of 5 growth factors that are necessary and sufficient to stimulate a marked mitogenic and differentiation response by a subset of human lin(-)CD34(-)CD38(-) cells present in normal adult human marrow and granulocyte colony-stimulating factor (G-CSF)-mobilized blood. Less than 0.1% of the cells in highly purified (including doubly sorted) lin(-)CD34(-)CD38(-) cells from these 2 sources formed colonies directly in semisolid medium or generated such cells a…
Human Wharton's jelly mesenchymal stem cells maintain the expression of key immunomodulatory molecules when subjected to osteogenic, adipogenic and c…
2013
Rheumatoid arthritis and osteoarthritis are the main diseases that imply an inflammatory process at the joints involving the articular cartilage. Recently, mesenchymal stem cells (MSCs) derived from perinatal tissues were considered good candidates for cellular therapy of musculoskeletal and orthopaedic diseases, since they can differentiate into multiple cell types and are an easily accessible cellular source. Therefore, several protocols exist on the differentiation of mesenchymal stem cells of different origins into osteoblasts and chondrocytes. Another key feature of MSCs is their capacity to modulate the immune system responses in vitro and in vivo. This may have critical outcomes in d…
Tumor-derived lactic acid modulates dendritic cell activation and antigen expression.
2005
The tumor milieu can influence dendritic cell (DC) differentiation. We analyzed DC differentiation in a 3-dimensional tumor model and propose a new mechanism of DC modulation by the tumor environment. Monocytes were cultured in the presence of IL-4 and GM-CSF within multicellular tumor spheroids (MCTSs) generated from different tumor cell lines. Monocytes invaded the MCTSs and differentiated into tumor-associated dendritic cells (TADCs). The antigen expression was altered on TADCs independent of the culture conditions (immature/mature DCs, Langerhans cells) and IL-12 secretion was reduced. Supernatants of MCTSs could partially transfer the suppressive effect. Conditioned media from urotheli…
Cellular interactions ofCandida albicanswith human oral epithelial cells and enterocytes
2010
The human pathogenic fungus Candida albicans can cause systemic infections by invading epithelial barriers to gain access to the bloodstream. One of the main reservoirs of C. albicans is the gastrointestinal tract and systemic infections predominantly originate from this niche. In this study, we used scanning electron and fluorescence microscopy, adhesion, invasion and damage assays, fungal mutants and a set of fungal and host cell inhibitors to investigate the interactions of C. albicans with oral epithelial cells and enterocytes. Our data demonstrate that adhesion, invasion and damage by C. albicans depend not only on fungal morphology and activity, but also on the epithelial cell type an…
Hemin induces germ tube formation in Candida albicans.
1997
Hemin induced germination of Candida albicans blastoconidia when cells grown up to the early exponential phase were shifted from 28 to 37 degrees C (70 to 75% of cells exhibited germ tubes). N-Acetyl-D-glucosamine (GlcNAc), another inducer of myceliation in this fungus, caused a similar effect. The combination of hemin and GlcNAc resulted in a higher percentage (95%) of blastoconidial germination. These results suggest that in addition to temperature, hemin levels and carbon source may coordinately regulate the expression of subsets of genes involved in the yeast-to-mycelium transition in C. albicans.
Th9 cells, new players in adaptive immunity.
2014
Upon antigen-specific stimulation, naive CD4⁺ T cells have the potential to differentiate into various T helper (Th) cell subsets. Earlier models of Th cell differentiation focused on IFN-γ-producing Th1 cells and IL-4-secreting Th2 cells. The discovery of additional CD4⁺ Th cell subsets has extended our understanding of Th cell differentiation beyond this dichotomy. Among these is the recently described Th9 cell subset, which preferentially produces interleukin (IL)-9. Here, we review the latest developments in Th9 cell development and differentiation, focusing on contributing environmental signals, and discuss potential physiological and pathophysiological functions of these cells. We des…
Differentiation of Type 1 ILCs from a Common Progenitor to All Helper-like Innate Lymphoid Cell Lineages
2014
SummaryInnate lymphoid cells (ILCs) are a recently recognized group of lymphocytes that have important functions in protecting epithelial barriers against infections and in maintaining organ homeostasis. ILCs have been categorized into three distinct groups, transcriptional circuitry and effector functions of which strikingly resemble the various T helper cell subsets. Here, we identify a common, Id2-expressing progenitor to all interleukin 7 receptor-expressing, “helper-like” ILC lineages, the CHILP. Interestingly, the CHILP differentiated into ILC2 and ILC3 lineages, but not into conventional natural killer (cNK) cells that have been considered an ILC1 subset. Instead, the CHILP gave rise…
Isolation and characterization of a murine resident liver stem cell.
2008
Increasing evidence provides support that mammalian liver contains stem/progenitor cells, but their molecular phenotype, embryological derivation, biology and their role in liver cell turnover and regeneration remain to be further clarified. In this study, we report the isolation, characterization and reproducible establishment in line of a resident liver stem cell (RLSC) with immunophenotype and differentiative potentiality distinct from other previously described liver precursor/stem cells. RLSCs, derived from fetal and neonatal murine livers as well as from immortalized hepatocytic MMH lines and established in lines, are Sca+, CD34-, CD45-, alpha-fetoprotein+ and albumin-. This molecular…
Evidence for a common progenitor of epithelial and mesenchymal components of the liver
2013
Tissues of the adult organism maintain the homeostasis and respond to injury by means of progenitor/stem cell compartments capable to give rise to appropriate progeny. In organs composed by histotypes of different embryological origins (e.g. The liver), the tissue turnover may in theory involve different stem/precursor cells able to respond coordinately to physiological or pathological stimuli. In the liver, a progenitor cell compartment, giving rise to hepatocytes and cholangiocytes, can be activated by chronic injury inhibiting hepatocyte proliferation. The precursor compartment guaranteeing turnover of hepatic stellate cells (HSCs) (perisinusoidal cells implicated with the origin of the …