Search results for "antigen-presenting cells"
showing 10 items of 91 documents
IL-10 down-regulates T cell activation by antigen-presenting liver sinusoidal endothelial cells through decreased antigen uptake via the mannose rece…
1998
SUMMARYOur study demonstrates that antigen-presenting liver sinusoidal endothelial cells (LSEC) induce production of interferon-gamma (IFN-γ) from cloned Th1 CD4+ T cells. We show that LSEC used the mannose receptor for antigen uptake, which further strengthened the role of LSEC as antigen-presenting cell (APC) population in the liver. The ability of LSEC to activate cloned CD4+ T cells antigen-specifically was down-regulated by exogenous prostaglandin E2 (PGE2) and by IL-10. We identify two separate mechanisms by which IL-10 down-regulated T cell activation through LSEC. IL-10 decreased the constitutive surface expression of MHC class II as well as of the accessory molecules CD80 and CD86 …
Identification of NY-ESO-1 epitopes presented by human histocompatibility antigen (HLA)-DRB4*0101-0103 and recognized by CD4(+) T lymphocytes of pati…
2000
NY-ESO-1 is a member of the cancer-testis family of tumor antigens that elicits strong humoral and cellular immune responses in patients with NY-ESO-1–expressing cancers. Since CD4+ T lymphocytes play a critical role in generating antigen-specific cytotoxic T lymphocyte and antibody responses, we searched for NY-ESO-1 epitopes presented by histocompatibility leukocyte antigen (HLA) class II molecules. Autologous monocyte-derived dendritic cells of cancer patients were incubated with recombinant NY-ESO-1 protein and used in enzyme-linked immunospot (ELISPOT) assays to detect NY-ESO-1–specific CD4+ T lymphocyte responses. To identify possible epitopes presented by distinct HLA class II allele…
Components of an antigen-/T cell receptor-independent pathway of lymphokine production
1991
The general way to induce the synthesis of lymphokines by T cells is the stimulation through the T cell receptor (TcR) complex which results in an increase of intracellular [Ca2+] and in the activation of a tyrosine kinase as well as of protein kinase C. Lymphokine production induced via the TcR is inhibited by the immunosuppressive drug cyclosporin A (CsA). However, an alternative pathway of lymphokine production exists. Several T lymphocyte clones can synthesize interferon-gamma (IFN-gamma), granulocyte-monocyte colony-stimulating factor, and small amounts of interleukin (IL3) when stimulated with syngeneic or allogeneic accessory cells (AC) plus IL2. In contrast to the TcR pathway the al…
Identification of NM23-H2 as a tumour-associated antigen in chronic myeloid leukaemia.
2008
Therapeutic effects of haematopoietic stem cell transplantation are not limited to maximal chemoradiotherapy and subsequent bone marrow regeneration, but include specific as well as unspecific immune reactions known as graft-versus-leukaemia (GvL) effects. Specific immune reactions are likely to be particularly relevant to the long-term treatment of diseases, such as chronic myeloid leukaemia (CML), in which residual cells may remain quiescent and unresponsive to cytotoxic and molecular therapies for long periods of time. Specific GvL effects result from the expression on leukaemic cells of specific tumour-associated antigens (TAAs) in the context of HLA proteins. As human leukocyte antigen…
Differentiation driven by granulocyte-macrophage colony-stimulating factor endows microglia with interferon-γ-independent antigen presentation functi…
1993
The antigen presentation function of microglial cells was analyzed after differentiation in neonatal mouse brain cell cultures supplemented either with macrophage (M) or granulocyte/macrophage (GM) colony-stimulating factor (CSF). The cells separated from concomitant astrocytes in both culture systems turned out to exhibit cytological characteristics of macrophages and bore MAC-1 and F4/80 markers in a similar way. When comparatively tested for accessory cell function, only microglia developed with GM-CSF were able to efficiently induce antigen-directed proliferation of a series of helper T cell lines representing both the TH1 and TH2 subtype. Antigenic T cell activation by this microglia p…
Requirements for the growth of TH1 lymphocyte clones.
1990
Besides the signal generated in a T lymphocyte after triggering the T cell receptor (TcR), most lymphocytes need a "second signal" to become fully activated. The necessity and nature of the "second signal" differs between different types of T cells. At the level of CD4-positive T helper lymphocytes interleukin 1 (IL 1) serves as "second signal" for those of the TH2 subtype (IL4, 5, 6 producer) but not for those of the TH1 subtype (IL 2, IFN-gamma producer). This correlates with the absence of the IL 1 receptor at the surface of TH1 clones. We report herein the further purification of T cell stimulating factor (TSF), a soluble mediator involved in the proliferation of TH1 lymphocytes. A prep…
Costimulatory signalling potential of murine MHC class II‐positive T‐clone cells
1996
Activated human and rat T cells as well as mouse T-cell clones have been reported to synthesize and express major histocompatibility complex (MHC) class II molecules. However, the capacity of class II+ antigen (Ag) presenting T cells to induce proliferation of Ag-specific cloned T cells has been controversial. We analysed whether the failure of some T-cell clones to proliferate in response to Ag presented by class II+ T cells is because of a lack of costimulatory cytokine production by the antigen-presenting cells (APC). As a model system the mouse class II+ cloned BI/O4.1 T cells were used as APC in order to activate the T cell clone KIII5. This T-helper 1 (Th1) type, GAT (synthetic copoly…
Endothelial Nitric Oxide Synthase Regulates T Cell Receptor Signaling at the Immunological Synapse
2006
The role of nitric oxide (NO) in T cells remains controversial, and the origin and localization of endogenous NO and whether it regulates lymphocyte activation are unclear. We show here that, within minutes of binding to antigen, T cells produce NO via endothelial nitric oxide synthase (eNOS). This process required increased intracellular Ca2+ and phosphoinositide3-kinase activity. By using an eNOS-green fluorescent fusion protein and fluorescent probes to detect NO, we show that eNOS translocates with the Golgi apparatus to the immune synapse of T helper cells engaged with antigen-presenting cells (APC), where it was fully activated. Overexpression of eNOS prevented the central coalescence…
Freshly isolated mouse 4F7+ splenic dendritic cells process and present exogenous antigens to T cells.
1994
The antibody 4F7 was reported to recognize an epitope expressed on dendritic cells (DC) from various tissues. To study the ability of splenic 4F7+ dendritic cells to process antigen for presentation to CD4+ T cells, DC were enriched using a separation procedure avoiding overnight culture which could lead to an altered phenotype. These DC were used as antigen-presenting cells (APC) in stimulation cultures of major histocompatibility complex class II-restricted T cells. It was found that they induce antigen-dependent lymphokine production by T cells and therefore could present exogenous antigens. These processing takes place intracellularly, because fixation abrogates presentation to T cells.…
Dendritic Cell-Specific Deletion of β-Catenin Results in Fewer Regulatory T-Cells without Exacerbating Autoimmune Collagen-Induced Arthritis.
2015
Dendritic cells (DCs) are professional antigen presenting cells that have the dual ability to stimulate immunity and maintain tolerance. However, the signalling pathways mediating tolerogenic DC function in vivo remain largely unknown. The beta-catenin pathway has been suggested to promote a regulatory DC phenotype. The aim of this study was to unravel the role of beta-catenin signalling to control DC function in the autoimmune collagen-induced arthritis model (CIA). Deletion of beta-catenin specifically in DCs was achieved by crossing conditional knockout mice with a CD11c-Cre transgenic mouse line. Bone marrow-derived DCs (BMDCs) were generated and used to study the maturation profile of …