Search results for "Cell Differentiation"
showing 10 items of 907 documents
Neuronal nitric oxide synthase modulates maturation of human dendritic cells.
2010
AbstractDendritic cells (DCs) are the most potent APCs of the immune system. Understanding the intercellular and intracellular signaling processes that lead to DC maturation is critical for determining how these cells initiate T cell-mediated immune processes. NO synthesized by the inducible NO synthase (iNOS) is important for the function of murine DCs. In our study, we investigated the regulation of the arginine/NO-system in human monocyte-derived DCs. Maturation of DCs induced by inflammatory cytokines (IL-1β, TNF, IL-6, and PGE2) resulted in a pronounced expression of neuronal NOS (nNOS) but only minimal levels of iNOS and endothelial NOS were detected in human mature DCs. In addition, …
Induction of tumor peptide-specific cytotoxic T cells under serum-free conditions by mature human dendritic cells
2000
Tumor vaccination strategies using antigen-pulsed dendritic cells (DC) are currently under development. We established an in vitro system using cultured DC from HLA-typed volunteers for the induction of tumor peptide-specific CD8+ T cells. The strength and specificity of the resulting CTL responses were investigated. For stimulation of syngeneic CD8+ T cells two well-defined DC populations were generated: CD1a+ immature DC cultured in the presence of GM-CSF and IL-4 and mature CD83+ DC generated by additional stimulation with a cytokine cocktail. Stimulations were performed under serum-free conditions and in the absence of exogenous cytokines. Analysis of T cell responses showed that mature…
Definition of the HLA-A2 restricted peptides recognized by human CD8+ effector T cells by flow-assisted sorting of the CD8+ CD45RA+ CD28– T cell subp…
2003
SUMMARY In response to antigenic stimulation, naive MHC-class I restricted and antigen-specific CD8+ CD45RA+ CD28+ T cells undergo clonal expansion, differentiate into CD8+ CD45RO+ memory T cells and convert to CD8+ CD45RA+ CD28− T cells displaying potent immune effector functions upon re-encounter with the nominal antigen. We show that the effector CD8+ CD45RA+ CD28– T cell subset is expanded in peripheral blood lymphocytes (PBL) from patients with human papilloma virus (HPV)+ cervical lesions as well as in PBL from patients with pulmonary tuberculosis. Flow-cytometric cell sorted CD8+ CD45RA+ CD28– and CD8+ CD45RA+ CD28– T cells were tested for recognition of HLA-A2 restricted peptides de…
The mitochondrial protein TCAIM regulates activation of T cells and thereby promotes tolerance induction of allogeneic transplants.
2013
Primary T cell activation and effector cell differentiation is required for rejection of allogeneic grafts in naive recipients. It has become evident, that mitochondria play an important role for T cell activation. Expression of several mitochondrial proteins such as TCAIM (T cell activation inhibitor, mitochondrial) is down-regulated upon T cell receptor triggering. Here we report that TCAIM inhibited spontaneous development of memory and effector T cells. CD4(+) T cells from Tcaim knock-in (KI) mice showed reduced activation, cytokine secretion and proliferation in vitro. Tcaim KI T cells tolerated allogeneic skin grafts upon transfer into Rag-1 KO mice. CD4(+) and CD8(+) T cells from the…
Enhanced dendritic cell maturation by TNF-alpha or cytidine-phosphate-guanosine DNA drives T cell activation in vitro and therapeutic anti-tumor immu…
2000
Abstract Dendritic cells (DC) manipulated ex vivo can induce tumor immunity in experimental murine tumor models. To improve DC-based tumor vaccination, we studied whether DC maturation affects the T cell-activating potential in vitro and the induction of tumor immunity in vivo. Maturation of murine bone marrow-derived DC was induced by GM-CSF plus IL-4 alone or by further addition of TNF-α or a cytidine-phosphate-guanosine (CpG)-containing oligonucleotide (ODN-1826), which mimics the immunostimulatory effect of bacterial DNA. Flow cytometric analysis of costimulatory molecules and MHC class II showed that DC maturation was stimulated most by ODN-1826, whereas TNF-α had an intermediate effec…
New therapies for sepsis: focus on the interleukin (IL)12 family member IL27
2007
Sepsis is a severe complication of abdominal infections such as peritonitis and is associated with high mortality. Unfortunately, the molecular mechanisms controlling the development of sepsis are still incompletely understood. Interestingly, the interleukin (IL) 12 family member IL27 seems to play a key role in sepsis. In a murine model of septic peritonitis induced by caecal ligation and puncture (CLP), IL27 levels were found to be strongly induced. Furthermore, mice deficient for the EBI3 subunit of IL27 were resistant to CLP-induced septic peritonitis as compared to wild-type controls. This effect could be suppressed by injection of recombinant IL27. Further studies demonstrated that IL…
Different Efficiency of Heat Shock Proteins (HSP) to Activate Human Monocytes and Dendritic Cells: Superiority of HSP60
2002
Abstract One essential immunoregulatory function of heat shock protein (HSP) is activation of the innate immune system. We investigated the activation of human monocytes and monocyte-derived dendritic cells (DC) by recombinant human HSP60, human inducible HSP72, and preparations of human gp96 and HSP70 under stringent conditions, in the absence of serum and with highly purified monocytes. HSP60 induced human DC maturation and activated human DC to secrete proinflammatory cytokines. HSP72 induced DC maturation to a lesser extent, but activated human monocytes and immature DC as efficiently as HSP60 to release proinflammatory cytokines. The independence of the effects of HSP60 and HSP72 from …
cIAP1-dependent TRAF2 degradation regulates the differentiation of monocytes into macrophages and their response to CD40 ligand.
2008
AbstractPeripheral blood monocytes are plastic cells that migrate to tissues and differentiate into various cell types, including macrophages, dendritic cells, and osteoclasts. We have described the migration of cellular inhibitor of apoptosis protein 1 (cIAP1), a member of the IAP family of proteins, from the nucleus to the Golgi apparatus in monocytes undergoing differentiation into macrophages. Here we show that, once in the cytoplasm, cIAP1 is involved in the degradation of the adaptor protein tumor necrosis factor receptor–associated factor 2 (TRAF2) by the proteosomal machinery. Inhibition of cIAP1 prevents the decrease in TRAF2 expression that characterizes macrophage formation. We d…
Neurogenesis and Neuronal Regeneration in the Adult Reptilian Brain
2002
Evidence accumulated over the last few decades demonstrates that all reptiles examined thus far continue to add neurons at a high rate and in many regions of the adult brain. This so-called adult neurogenesis has been described in the olfactory bulbs, rostral forebrain, all cortical areas, anterior dorsal ventricular ridge, septum, striatum, nucleus sphericus, and cerebellum. The rate of neuronal production varies greatly among these brain areas. Moreover, striking differences in the rate and distribution of adult neurogenesis have been noted among species. In addition to producing new neurons in the adult brain, lizards, and possibly other reptiles as well, are capable of regenerating larg…
The proliferative ventricular zone in adult vertebrates: a comparative study using reptiles, birds, and mammals
2002
Although evidence accumulated during the last decades has advanced our understanding of adult neurogenesis in the vertebrate brain, many aspects of this intriguing phenomenon remain controversial. Here we review the organization and cellular composition of the ventricular wall of reptiles, birds, and mammals in an effort to identify differences and commonalities among these vertebrate classes. Three major cell types have been identified in the ventricular zone of reptiles and birds: migrating (Type A) cells, radial glial (Type B) cells, and ependymal (Type E) cells. Cells similar anatomically and functionally to Types A, B, and E have also been described in the ventricular wall of mammals, …