Cell Stimulatory Capacity (cell + stimulatory_capacity)

Distribution by Scientific Domains

Selected Abstracts

Modulation of dendritic cell phenotype and functionin an in vitro model of the intestinal epithelium

Matt Butler
Abstract A network of dendritic cells (DC) can be detected in close proximity to the epithelial cells overlying Peyer's patches in the gut. Intestinal DC show distinct phenotypes as compared to DC from the systemic lymph nodes (relatively low MHC and costimulatory molecules and high IL-10 and TGF,) and may play a role in maintaining tolerance to enteric antigens. We show that a similar phenotype is induced in the presence of a polarised epithelial cell monolayer in vitro. Monocyte-derived DC were co-cultured with Caco-2 intestinal epithelial monolayers for 24,h. Co-culture resulted in DC with reduced expression of MHC class,II, CD86, and CD80, and poor T,cell stimulatory capacity. Cytokine profiles showed reduced levels of inflammatory cytokine production, and co-cultured DC were less sensitive to stimulation via Toll-like receptors (TLR2, 4, and 6) as a result of increased levels of autocrine TGF, production. However, phenotypic changes in co-cultured DC could not be blocked by removal of apoptotic cells or addition of anti-TGF, antibodies, suggesting that other soluble factors are involved in DC modulation. Thus, polarised epithelial cell monolayers create a ,tolerogenic' environment which modulates the activity of DC. These results highlight the regulatory importance of the epithelial microenvironment at mucosal surfaces. [source]

Inhibition of Obliterative Airway Disease Development in Murine Tracheal Allografts by Matrix Metalloproteinase-9 Deficiency

Félix G. Fernández
This study was designed to define the roles of matrix metalloproteinase (MMP)-2 and MMP-9 in obliterative airway disease (OAD) in heterotopic murine tracheal allografts, considered a suitable animal model for chronic lung allograft rejection. BALB/c tracheal allografts were transplanted into MMP-2-deficient (,/,) and MMP-9,/, mice. Also, wild-type recipients were treated with doxycycline, a nonspecific MMP inhibitor. After 10, 20 and 30 days, allografts were analyzed for OAD development, intragraft levels of MMP-2 and MMP-9 and the frequency and cytokine/chemokine production profile of alloreactive T cells. Allografts transplanted into wild-type mice developed OAD lesions within 30 days. These allografts revealed significant upregulation of both MMP-2 and MMP-9. Allografts transplanted into MMP-9,/, and doxycycline-treated recipients did not develop OAD. In contrast, allografts transplanted into MMP-2,/, mice developed OAD lesions with normal kinetics. Interestingly, MMP-9,/, recipients showed an enhanced T cell alloreactivity associated with an abnormal profile of cytokine/chemokine production. The enhanced T cell alloreactivity in MMP-9,/, mice was mediated by enhanced dendritic cell stimulatory capacity as well as enhanced T cell responsive capacity. These results suggest that MMP-9 plays an important role in the pathogenesis of OAD and may represent a target for the therapeutic intervention of chronic lung allograft rejection. [source]

Mouse dendritic cells matured by ingestion of apoptotic blebs induce T cells to produce interleukin-17

Justin H. Fransen
Objective Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the formation of antinuclear autoantibodies. Increased apoptosis and reduced clearance of apoptotic material have been assigned a role in the pathogenesis of SLE, but the underlying mechanisms remain elusive. During apoptosis apoptotic blebs are formed in which autoantigens are clustered. The cellular remnants after blebbing are referred to as apoptotic cell bodies. We undertook this study to compare the effects of apoptotic blebs and apoptotic cell bodies on maturation of dendritic cells (DCs) and their T cell stimulatory capacity in a murine setting. Methods The uptake by DCs of apoptotic blebs and apoptotic cell bodies was analyzed by flow cytometry and confocal microscopy. DC maturation and DC-induced T cell activation were determined by measuring expression of costimulatory molecules using flow cytometry and by measuring production of cytokines using enzyme-linked immunosorbent assay. Results DCs internalized apoptotic blebs more efficiently than apoptotic cell bodies. Incubation of DCs with apoptotic blebs resulted in increased CD40 and CD86 expression and increased interleukin-6 (IL-6) and tumor necrosis factor , production, while apoptotic cell bodies had no stimulatory effects. Using chloroquine, apoptotic bleb,induced DC maturation was shown to be independent of Toll-like receptors 3, 7, and 9. Interestingly, in cocultures with allogeneic T cells, bleb-matured DCs induced production of IL-2, interferon-,, and, in particular, IL-17, suggesting a Th1/Th17 response. Conclusion Apoptotic blebs, in contrast to apoptotic cell bodies, induce DC maturation, thereby providing DCs with increased Th17 cell stimulatory capacity. These data imply that apoptotic bleb,induced DC maturation represents an important driving force in the autoimmune response in SLE. [source]

Immunotherapy using autologous monocyte-derived dendritic cells pulsed with leukemic cell lysates for acute myeloid leukemia relapse after autologous peripheral blood stem cell transplantation

Je-Jung Lee
Abstract Although a second stem cell transplantation (SCT) can be used as salvage therapy in patients with relapsing leukemia after SCT, most of these patients have a poor outcome. We tried clinical vaccination using monocyte-derived dendritic cells (DCs) pulsed with leukemic lysates to treat relapsing acute myeloid leukemia (AML) after autologous SCT. To generate DCs, CD14+ cells isolated from peripheral blood stem cell products were cultured in AIM-V in the presence of GM-CSF and IL-4. Adding TNF-, on day 6 induced maturation of the DCs, which were harvested on day 8 or 9. The DCs were incubated with tumor lysate and KLH for 2 hr at 37°C. After certifying the absence of microorganisms and endotoxins, the patients received four DC vaccinations at two- to three-week intervals. Two patients received four DC vaccinations with means of 7.8 × 106 and 9 × 106 DCs at two- to three-week intervals. The DC vaccinations were well tolerated with no apparent side effects. After the vaccinations, the patients showed immunological responses with positive delayed-type hypersensitivity skin reaction and increasing autologous T cells stimulatory capacity to the DCs; however, the BM blast percentage of the patients did not improve. The results suggest that DCs are a feasible cellular therapy for relapsing AML after autologous SCT. J Clin Apheresis 19:66,70, 2004. © 2004 Wiley-Liss, Inc. [source]