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Cells Able (cell + able)
Selected AbstractsGlucose-responsive insulin-producing cells from stem cellsDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 6 2002David J. Kaczorowski Abstract Recent success with immunosuppression following islet cell transplantation offers hope that a cell transplantation treatment for type 1 (juvenile) diabetes may be possible if sufficient quantities of safe and effective cells can be produced. For the treatment of type 1 diabetes, the two therapeutically essential functions are the ability to monitor blood glucose levels and the production of corresponding and sufficient levels of mature insulin to maintain glycemic control. Stem cells can replicate themselves and produce cells that take on more specialized functions. If a source of stem cells capable of yielding glucose-responsive insulin-producing (GRIP) cells can be identified, then transplantation-based treatment for type 1 diabetes may become widely available. Currently, stem cells from embryonic and adult sources are being investigated for their ability to proliferate and differentiate into cells with GRIP function. Human embryonic pluripotent stem cells, commonly referred to as embryonic stem (ES) cells and embryonic germ (EG) cells, have received significant attention owing to their broad capacity to differentiate and ability to proliferate well in culture. Their application to diabetes research is of particular promise, as it has been demonstrated that mouse ES cells are capable of producing cells able to normalize glucose levels of diabetic mice, and human ES cells can differentiate into cells capable of insulin production. Cells with GRIP function have also been derived from stem cells residing in adult organisms, here referred to as endogenous stem cell sources. Independent of source, stem cells capable of producing cells with GRIP function may provide a widely available cell transplantation treatment for type 1 diabetes. Copyright © 2002 John Wiley & Sons, Ltd. [source] Decreased specific CD8+ T,cell cross-reactivity of antigen recognition following vaccination with Melan-A peptideEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2006Victor Appay Abstract The aim of T,cell vaccines is the expansion of antigen-specific T,cells able to confer immune protection against pathogens or tumors. Although increase in absolute cell numbers, effector functions and TCR repertoire of vaccine-induced T,cells are often evaluated, their reactivity for the cognate antigen versus their cross-reactive potential is rarely considered. In fact, little information is available regarding the influence of vaccines on T,cell fine specificity of antigen recognition despite the impact that this feature may have in protective immunity. To shed light on the cross-reactive potential of vaccine-induced cells, we analyzed the reactivity of CD8+ T,cells following vaccination of HLA-A2+ melanoma patients with Melan-A peptide, incomplete Freund's adjuvant and CpG-oligodeoxynucleotide adjuvant, which was shown to induce strong expansion of Melan-A-reactive CD8+ T,cells in vivo. A collection of predicted Melan-A cross-reactive peptides, identified from a combinatorial peptide library, was used to probe functional antigen recognition of PBMC ex vivo and Melan-A-reactive CD8+ T,cell clones. While Melan-A-reactive CD8+ T,cells prior to vaccination are usually constituted of widely cross-reactive naive cells, we show that peptide vaccination resulted in expansion of memory T,cells displaying a reactivity predominantly restricted to the antigen of interest. Importantly, these cells are tumor-reactive. [source] Induction of blood-brain barrier properties in cultured brain capillary endothelial cells: Comparison between primary glial cells and C6 cell lineGLIA, Issue 3 2005Monica Boveri Abstract The communication between glial cells and brain capillary endothelial cells is crucial for a well-differentiated blood-brain barrier (BBB). It has been suggested that in vitro primary glial cells (GCs) be replaced by the glial C6 cell line to standardise the model further. This study compares directly the structural and functional differentiation of bovine brain capillary endothelial cells (BBCECs) induced by co-culture with rat primary GCs or C6 cells, for the first time. Trans-endothelial electrical resistance (TEER) measurements showed that under no condition were C6 cells able to reproduce TEER values as high as in the presence of GCs. At the same time, permeability of the BBCECs to both radioactive sucrose and FITC-inulin was 2.5-fold higher when cells were co-cultured with C6 than with GCs. Furthermore, immunocytochemistry studies showed different cell morphology and less developed tight junction pattern of BBCECs co-cultured with C6 toward GCs. Additionally, studies on P-glycoprotein (P-gp) showed much lower P-gp presence and activity in BBCECs co-cultured with C6 than GCs. Both VEGF mRNA expression and protein content were dramatically increased when compared with GCs, suggesting that VEGF could be one of the factors responsible for higher permeability of BBB. Our results clearly indicate that, in the presence of the glial C6 cell line, BBCECs did not differentiate as well as in the co-culture with primary GCs at both structural and functional levels. © 2005 Wiley-Liss, Inc. [source] Alpha-6 integrin is necessary for the tumourigenicity of a stem cell-like subpopulation within the MCF7 breast cancer cell lineINTERNATIONAL JOURNAL OF CANCER, Issue 2 2008Massimiliano Cariati Abstract The identification of mammary epithelial stem cells raises the hypothesis that these cells may be crucial in the pathogenesis of breast cancer. To further support this, a highly tumourigenic sub-population of cancer cells has recently been identified in primary and metastatic breast cancer samples. In this study, a sub-population of cells displaying features normally attributed to stem cells was identified within the breast cancer cell line MCF-7. This sub-population is capable of growth in anchorage-independent conditions as spherical organoids, displays resistance to proapoptotic agents and significantly greater tumourigenicity than its parental line, with as few as 1,000 cells able to form tumours in immunodeficient mice. Cells within this sub-population can be enriched by serial passages in anchorage-independence, and are characterized by over-expression of the adhesion molecule ,6-integrin. Alpha-6 integrin proves to be required for the growth and survival of these cells, as the knockdown of ITGA6 causes mammosphere-derived cells to lose their ability to grow as mammospheres and abrogates their tumourigenicity in mice. These findings support the existence of a highly tumourigenic sub-population in breast cancer cells. Furthermore, it shows ,6-integrin as a potential therapeutic target aimed at tumour-generating subsets of breast cancer cells. © 2007 Wiley-Liss, Inc. [source] Plasticity of death rates in stationary phase in Saccharomyces cerevisiaeAGING CELL, Issue 1 2009Nadège Minois Summary For the species that have been most carefully studied, mortality rises with age and then plateaus or declines at advanced ages, except for yeast. Remarkably, mortality for yeast can rise, fall and rise again. In the present study we investigated (i) if this complicated shape could be modulated by environmental conditions by measuring mortality with different food media and temperature; (ii) if it is triggered by biological heterogeneity by measuring mortality in stationary phase in populations fractionated into subpopulations of young, virgin cells, and replicatively older, non-virgin cells. We also discussed the results of a staining method to measure viability instead of measuring the number of cells able to exit stationary phase and form a colony. We showed that different shapes of age-specific death rates were observed and that their appearance depended on the environmental conditions. Furthermore, biological heterogeneity explained the shapes of mortality with homogeneous populations of young, virgin cells exhibiting a simple shape of mortality in conditions under which more heterogeneous populations of older cells or unfractionated populations displayed complicated death rates. Finally, the staining method suggested that cells lost the capacity to exit stationary phase and to divide long before they died in stationary phase. These results explain a phenomenon that was puzzling because it appeared to reflect a radical departure from mortality patterns observed for other species. [source] Macaques co-immunized with SIVgag/pol-HIVenv and IL-12 plasmid have increased cellular responsesJOURNAL OF MEDICAL PRIMATOLOGY, Issue 4-5 2007T.M. Robinson Abstract Background, The cell mediated immune profiles following immunization with a recombinant DNA vaccine was assessed in the simian-human immunodeficiency virus (SHIV) and Macaque model. Earlier work demonstrated increased numbers of antigen specific CD8 and CD4 effector cells able to secrete IFN- ,. Method, The vaccine strategy included co-immunization of a DNA based vaccine alone or in combination with a macaque IL-12 expressing plasmid (pmacIL12). Antigen activated lymphocytes were studied for activation of a set of immunological molecules. Results, The current study demonstrates lymphocytes isolated and activated from the group that was immunized with DNA and pmacIL12 had a higher level of IFN- , producing cells. We also observed a different immunological profile when comparing the cells isolated from macaques immunized with DNA as compared to those animals that also received pmacIL12. Conclusion, The observed immune profiles are reflective of the co-delivery of pmacIL12 and demonstrates that IL-12 can increase the magnitude and polyfunctionality of the cellular immune response. [source] Indirect CD4+ TH1 Response, Antidonor Antibodies and Diffuse C4d Graft Deposits in Long-Term Recipients Conditioned by Donor Antigens PrimingAMERICAN JOURNAL OF TRANSPLANTATION, Issue 4 2009C. Ballet Priming of recipients by DST induces long-term survival of mismatched allografts in adult rats. Despite these recipients developing inducible T regulatory cells able to transfer long-term graft survival to a secondary host, a state of chronic rejection is also observed. We revisited the molecular donor MHC targets of the cellular response in acute rejection and analyzed the cellular and humoral responses in recipients with long-term graft survival following transplantation. We found three immunodominant peptides, all derived from LEW.1W RT1.Du molecules to be involved in acute rejection of grafts from unmodified LEW.1A recipients. Although the direct pathway of allorecognition was reduced in DST-treated recipients, the early CD4+ indirect pathway response to dominant peptides was almost unimpaired. We also detected early and sustained antidonor class I and II antibody subtypes with diffuse C4d deposits on graft vessels. Finally, long-term accepted grafts displayed leukocyte infiltration, endarteritis and fibrosis, which evolved toward vascular narrowing at day 100. Altogether, these data suggest that the chronic graft lesions developed in long-term graft recipients are the result of progressive humoral injury associated with a persisting indirect T helper response. These features may represent a useful model for understanding and manipulating chronic active antibody-mediated rejection in human. [source] Interferon-,2a is sufficient for promoting dendritic cell immunogenicityCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2005A. Tamir Summary Type I interferons (IFNs) are widely used therapeutically. IFN-,2a in particular is used as an antiviral agent, but its immunomodulatory properties are poorly understood. Dendritic cells (DCs) are the only antigen-presenting cells able to prime naive T cells and therefore play a crucial role in initiating the adaptive phase of the immune response. We studied the effects of IFN-,2a on DC maturation and its role in determining Th1/Th2 equilibrium. We found that IFN-,2a induced phenotypic maturation of DCs and increased their allostimulatory capacity. When dendritic cells were stimulated simultaneously by CD40 ligation and IFN-,2a, the production of interleukin (IL)-10 and IL-12 was increased. In contrast, lipopolysaccharide (LPS) stimulation in the presence of IFN-,2a mainly induced IL-10 release. The production of IFN-, and IL-5 by the responder naive T cells was also amplified in response to IFN-,2a-treated DCs. Furthermore, IL-12 production by IFN-,2a-treated DCs was enhanced further in the presence of anti-IL-10 antibody. Different results were obtained when DCs were treated simultaneously with IFN-,2a and other maturation factors, in particular LPS, and then stimulated by CD40 ligation 36 h later. Under these circumstances, IFN-,2a did not modify the DC phenotype, and the production of IL-10/IL-12 and IFN-,/IL-5 by DCs and by DC-stimulated naive T cells, respectively, was inhibited compared to the effects on DCs treated with maturation factors alone. Altogether, this work suggests that IFN-,2a in isolation is sufficient to promote DC activation, however, other concomitant events, such as exposure to LPS during a bacterial infection, can inhibit its effects. These results clarify some of the in vivo findings obtained with IFN-,2a and have direct implications for the design of IFN-,-based vaccines for immunotherapy. [source] | |||||||||||||