Search results for "Immune system"

Idelalisib Impairs TREM-1 and TLR Mediated Neutrophil Activation

2016

Abstract Introduction: Polymorphonuclear neutrophils (PMN) play an essential role in innate inflammatory processes. Their functions are strictly regulated and many activating / inhibiting mechanisms along with their pathways are only incompletely understood. Besides toll-like receptors (TLR) and NOD-like receptors (NLR), triggering receptor expressed on myeloid cells (TREM)-1 is implicated in innate immune activation of these cells and plays a role in infectious as well as non-infectious conditions. Activation of TREM-1 results in release of pro-inflammatory chemokines and cytokines, increased surface expression of cell activation markers and degranulation. In TREM-1 downstream pathways and…

Molecular characterization of an inducible p-coumaric acid decarboxylase from Lactobacillus plantarum: gene cloning, transcriptional analysis, overex…

1997

By using degenerate primers designed from the first 19 N-terminal amino acids of Lactobacillus plantarum p-coumaric acid decarboxylase (PDC), a 56-bp fragment was amplified from L. plantarum in PCRs and used as a probe for screening an L. plantarum genomic bank. Of the 2,880 clones in the genomic bank, one was isolated by colony hybridization and contained a 519-bp open reading frame (pdc gene) followed by a putative terminator structure. The pdc gene is expressed on a monocistronic transcriptional unit, which is transcribed from promoter sequences homologous to Lactococcus promoter sequences. No mRNA from pdc and no PDC activity were detected in uninduced cell extracts, indicating that the…

Tick Salivary Sialostatin L Represses the Initiation of Immune Responses by Targeting IRF4-Dependent Transcription in Murine Mast Cells

2015

Abstract Coevolution of ticks and the vertebrate immune system has led to the development of immunosuppressive molecules that prevent immediate response of skin-resident immune cells to quickly fend off the parasite. In this article, we demonstrate that the tick-derived immunosuppressor sialostatin L restrains IL-9 production by mast cells, whereas degranulation and IL-6 expression are both unaffected. In addition, the expression of IL-1β and IRF4 is strongly reduced in the presence of sialostatin L. Correspondingly, IRF4- or IL-1R–deficient mast cells exhibit a strong impairment in IL-9 production, demonstrating the importance of IRF4 and IL-1 in the regulation of the Il9 locus in mast cel…

T-bet and mucosal Th1 responses in the gastrointestinal tract

2002

T cells play an essential role in regulating mucosal immune responses in the gastrointestinal tract. Recent observations on T helper cell differentiation and activation by regulatory transcription factors-especially T-bet-in chronic inflammatory diseases have provided new perspectives for understanding mucosal immunity. Here we summarise recent advances in the field of transcription factors and discuss the implications of these findings for future therapeutic approaches in inflammatory bowel diseases. In particular, we have focused on the role of T-bet in controlling mucosal Th1 responses in the gastrointestinal tract.

Transcriptional targeting of dendritic cells in gene gun-mediated DNA immunization favors the induction of type 1 immune responses

2003

Cutaneous dendritic cells (DC) are pivotal for the elicitation of antigen-specific immune responses following gene gun-mediated biolistic transfection of the skin. We transcriptionally targeted transgene expression to DC using vectors containing the murine fascin promoter (pFascin) to control antigen production and compared the immune response elicited with conventional DNA immunization using plasmid constructs with the ubiquitously active CMV promoter (pCMV). Biolistic transfection with pFascin initiated a marked type 1 immune response characterized by the occurrence of a large population of IFN-gamma-producing T helper (Th) cells in spleen and draining lymph nodes. Consistently, immunoglo…

Immune Evasion Proteins Enhance Cytomegalovirus Latency in the Lungs

2009

ABSTRACT CD8 T cells control cytomegalovirus (CMV) infection in bone marrow transplantation recipients and persist in latently infected lungs as effector memory cells for continuous sensing of reactivated viral gene expression. Here we have addressed the question of whether viral immunoevasins, glycoproteins that specifically interfere with antigen presentation to CD8 T cells, have an impact on viral latency in the murine model. The data show that deletion of immunoevasin genes in murine CMV accelerates the clearance of productive infection during hematopoietic reconstitution and leads to a reduced latent viral genome load, reduced latency-associated viral transcription, and a lower inciden…

1432P Characterizing diversity in the immune profile by a transcriptomic customized gene signature to potentially personalize treatment in advanced g…

2021

Release of dendritic cells from cognate CD4 + T-cell recognition results in impaired peripheral tolerance and fatal cytotoxic T-cell mediated autoimm…

2012

Resting dendritic cells (DCs) induce tolerance of peripheral T cells that have escaped thymic negative selection and thus contribute significantly to protection against autoimmunity. We recently showed that CD4 + Foxp3 + regulatory T cells (Tregs) are important for maintaining the steady-state phenotype of DCs and their tolerizing capacity in vivo. We now provide evidence that DC activation in the absence of Tregs is a direct consequence of missing DC–Treg interactions rather than being secondary to generalized autoimmunity in Treg-less mice. We show that DCs that lack MHC class II and thus cannot make cognate interactions with CD4 + T cells are completely unable to induce peripheral CD8 +…

Interleukin-7 matures suppressive CD127(+) forkhead box P3 (FoxP3)(+) T cells into CD127(-) CD25(high) FoxP3(+) regulatory T cells.

2011

We have identified a novel interleukin (IL)-7-responsive T cell population [forkhead box P3 (FoxP3(+) ) CD4(+) CD25(+) CD127(+) ] that is comparably functionally suppressive to conventional FoxP3(+) CD4(+) CD25(+) regulatory T cells (T(regs) ). Although IL-2 is the most critical cytokine for thymic development of FoxP3(+) T(regs) , in the periphery other cytokines can be compensatory. CD25(+) CD127(+) T cells treated with IL-7 phenotypically 'matured' into the known 'classical' FoxP3(+) CD4(+) CD25(high) CD127(-) FoxP3(+) T(regs) . In freshly isolated splenocytes, the highest level of FoxP3 expression was found in CD127(+) CD25(+) T cells when compared with CD127(-) CD25(+) or CD127(+) CD25…

EVOLUTION OF THE INNATE AND ADAPTIVE IMMUNE SYSTEMS

1999

Porifera (sponge) form the lowest metazoan phylum and share a common ancestor with other metazoan phyla. In the present study, it is reported that sponges possess molecules that are similar in structure to those molecules involved in the immune system in mammals. Experiments with the marine sponges Geodia cydonium and Suberites domuncula have been performed on tissue (auto- and allografting) as well as on a cellular level. The studies revealed that sponges are provided with elements of the mammalian innate immune system, such as molecules containing scavenger receptor cysteine-rich domains. Furthermore, macrophage-derived cytokine-like molecules have been identified that are up-regulated du…