Search results for "Immune tolerance"
showing 10 items of 174 documents
Regulatory T Cells and IL-10 Independently Counterregulate Cytotoxic T Lymphocyte Responses Induced by Transcutaneous Immunization
2011
Background: The imidazoquinoline derivate imiquimod induces inflammatory responses and protection against transplanted tumors when applied to the skin in combination with a cognate peptide epitope (transcutaneous immunization, TCI). Here we investigated the role of regulatory T cells (Treg) and the suppressive cytokine IL-10 in restricting TCI-induced cytotoxic T lymphocyte (CTL) responses. Methodology/Principal Findings: TCI was performed with an ointment containing the TLR7 agonist imiquimod and a CTL epitope was applied to the depilated back skin of C57BL/6 mice. Using specific antibodies and FoxP3-diphteria toxin receptor transgenic (DEREG) mice, we interrogated inhibiting factors after…
Virally Infected Mouse Liver Endothelial Cells Trigger CD8+ T-Cell Immunity
2009
Background & Aims Dendritic cell activation through ligation of pattern recognition receptors leading to full functional maturation causes induction of CD8 + T-cell immunity through increased delivery of costimulatory signals instead of tolerance. Here we investigate whether organ-resident antigen-presenting cells, such as liver sinusoidal endothelial cells (LSECs), also switch from tolerogenic to immunogenic CD8 + T-cell activation upon such stimulation. Methods Murine LSECs were isolated by immunomagnetic separation and analyzed for functional maturation upon triggering pattern recognition receptors or viral infection employing gene expression analysis and T cell coculture assays. In vivo…
Myeloid dendritic cell: From sentinel of immunity to key player of peripheral tolerance?
2009
Myeloid dendritic cells (DC) are "sentinels" of immunity, ideally positioned throughout the body gateways and equipped with unique properties to transport antigens from the periphery to lymphoid tissues. They are professional antigen-presenting cells transmitting incoming infectious signals to T cells, the key players of adaptive immunity. For induction of effective antigen-specific T-cell immunity, crosstalk of DC and naive T cells is mandatory. However, besides this essential immunostimulatory function of DC, consolidated findings from the DC research field in the last 10 years have shown that DC have an additional important function. They act as pivotal players in the peripheral toleranc…
Friend retrovirus infection of myeloid dendritic cells impairs maturation, prolongs contact to naïve T cells, and favors expansion of regulatory T ce…
2007
AbstractRetroviruses have developed immunmodulatory mechanisms to avoid being attacked by the immune system. The mechanisms of this retrovirus-associated immune suppression are far from clarified. Dendritic cells (DCs) have been attributed a decisive role in these pathogenic processes. We have used the Friend retrovirus (FV) mouse model in order to acquire further knowledge about the role of infection of DCs in virus-induced immunosuppression. About 20% of the myeloid DCs that were generated from the bone marrow of FV-infected mice carried FV proteins. The infection was productive, and infected DCs transmitted the virus in cell culture and in vivo. FV infection of DCs led to a defect in DC …
IL-10 Controls Ultraviolet-Induced Carcinogenesis in Mice
2007
Abstract UV radiation-induced immunosuppression contributes significantly to the development of UV-induced skin cancer by inhibiting protective immune responses. IL-10 has been shown to be a key mediator of UV-induced immunosuppression. To investigate the role of IL-10 during photocarcinogenesis, groups of IL-10+/+, IL-10+/−, and IL-10−/− mice were chronically irradiated with UV. IL-10+/+ and IL-10+/− mice developed skin cancer to similar extents, whereas IL-10−/− mice were protected against the induction of skin malignancies by UV. Because UV is able to induce regulatory T cells, which play a role in the suppression of protective immunity, UV-induced regulatory T cell function was analyzed…
Characterization of neutrophil subsets in healthy human pregnancies
2014
We have previously shown that in successful pregnancies increased arginase activity is a mechanism that contributes to the suppression of the maternal immune system. We identified the main type of arginase-expressing cells as a population of activated low-density granulocytes (LDGs) in peripheral blood mononuclear cells and in term placentae. In the present study, we analyzed the phenotype of LDGs and compared it to the phenotype of normal density granulocytes (NDGs) in maternal peripheral blood, placental biopsies and cord blood. Our data reveal that only LDGs but no NDGs could be detected in placental biopsies. Phenotypically, NDGs and LDGs from both maternal and cord blood expressed diff…
Immunophenotype based on inflammatory cells, PD-1/PD-L1 signalling pathway and M2 macrophages predicts survival in gastric cancer
2020
Abstract Background Immune response against cancer has prognostic impact but its role in gastric cancer is poorly known. The aim of the study was to assess the prognostic significance of immune cell score (CD3+, CD8+), tumour immune escape (PD-L1, PD-1) and immune tolerance (Clever-1). Methods After exclusion of Epstein-Barr virus positive (n = 4) and microsatellite instable (n = 6) tumours, the study included 122 patients with GC undergoing D2 gastrectomy. CD3+ and CD8+ based ICS, PD-L1, PD-1 and Clever-1 expressions were evaluated. Differences in survival were examined using Cox regression adjusted for confounders. The primary outcome was 5-year survival. Results The 5-year overall surviv…
Dynamic regulation of CD8 T cell tolerance induction by liver sinusoidal endothelial cells.
2010
Abstract Cross-presentation of soluble Ag on MHC class I molecules to naive CD8 T cells by liver sinusoidal endothelial cells (LSECs) leads to induction of T cell tolerance that requires interaction between coinhibitory B7-H1 on LSECs and programmed cell death-1 on CD8 T cells. In this study, we investigate whether cross-presentation of high as well as low Ag concentrations allowed for LSEC-induced tolerance. Ag concentration directly correlated with the cross-presentation capacity of murine LSECs and thus strength of TCR stimulation. Although LSEC cross-presentation at low-Ag concentrations resulted in tolerance, they induced differentiation into effector T cells (CTL) at high-Ag concentra…
Immunoreactivity of Roach,Rutilus rutilus,Following Laboratory Exposure to Bleached Pulp and Paper Mill Effluents
1998
Abstract In order to study immunomodulation, controlled laboratory experiments were carried out with roach ( Rutilus rutilus ) exposed to bleached kraft mill effluent (BKME) or spent bleach liquor (SBL) from two pulp and paper mills using elementary chlorine and chlorine dioxide for bleaching. The total number of immunoglobulin-secreting cells (ISC) and the number of specific antibody-secreting cells (ASC) were determined by ELISPOT assay. Exposure to BKME resulted in decreased numbers of ISC in the spleen. To study the capability of response against foreign antigens the fish were immunized with bovine γ-globulin. Exposure to BKME or SBL reduced antigen-specific ASC response in fish. Moreov…
Immunity, resistance and tolerance in bird-parasite interactions.
2013
12 pages; International audience; Interacting pathogens and hosts have evolved reciprocal adaptations whose function is to allow host exploitation (from the pathogen stand point) or minimize the cost of infection (from the host stand point). Once infected, two strategies are offered to the host: parasite clearing (resistance) or withstanding the infection while paying a low fitness cost (tolerance). In both cases, the immune system plays a central role. Interestingly, whatever the defence strategy adopted by the host, this is likely to have an effect on parasite evolution. Given their short generation time and large population size, parasites are expected to rapidly adapt to the environment…