Molecular Mechanisms of the AICD Paradoxon in Human T Cells Revealed by an Apototic Role for CD25.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 5236-5236
Author(s):  
Guenther Richter ◽  
Karin Hanewinkel ◽  
Andreas Mollweide ◽  
Stefan Burdach
Keyword(s):  
T Cell ◽  
Cell Transplantation ◽  
Microarray Analysis ◽  
T Cell Activation ◽  
Cell Activation ◽  
Molecular Mechanisms ◽  
Hematopoietic Cell Transplantation ◽  
Hematopoietic Cell ◽  
Graft Versus Host Reaction ◽  
Dual Function

Abstract The IL2R is a heterotrimeric receptor consisting of the alpha-chain (CD25) and the two signal transducing beta-, gamma-chains. CD25 monoclonal antibody (e.g. daclizumab) binding to the α-chain, blocks high affinity IL2 binding thereby preventing complete T cell activation. This opportunity to hinder T cell triggering is of ample importance in transplantation medicine and the treatment of autoimmune disease; e.g. for the prevention of an acute graft versus host reaction during allogeneic hematopoietic cell transplantation. However, gene-targeting experiments revealed, that CD25 has an important role in mediating activation induced cell death (AICD) thereby maintaining T cell homeostasis. Thus, CD25 antibodies may not only block T cell activation but may also prevent AICD attributing a dual function to IL2, which has been described by the term AICD paradoxon. The molecular mechanisms of AICD remain to be elucidated. In this study, the modulation of the genomic expression profile of human peripheral blood mononuclear cells (PBMC) with therapeutic concentrations of CD25 mAb was investigated with the aim to identify genes that are involved in T cell activation or in AICD. PBMC were stimulated with OKT3 together with recombinant IL2 in the absence or presence of 30 microgram/ml Daclizumab. Cells were incubated for 16 hrs, RNA extracted and subjected to microarray analysis on U133A gene chips (Affymetrix). Gene chip profile revealed up-regulation of 60 genes and down regulation of 36 genes respectively, by Daclizumab. Anti-CD25 treatment inhibitied cytokine genes typically expressed during T cell activation including CD40L, IL9, TNF-alpha and IFN-gamma as previously shown (e.g. Burdach et al., JCI). Surprisingly, daclizumab also blocked expression of several genes important for susceptibility to apoptosis, such as DR6. In addition, daclizumab reversed IL2-mediated repression of anti-apoptotic genes, such as TOSO. Microarray analysis of these apoptosis related genes was confirmed by RT-PCR and functional assays. In conclusion, CD25-mediated induction of pro-apoptotic as well as repression of anti-apoptotic gene clusters should be considered for future drug development of CD25-antibodies in the clinical arena: these apoptosis related gene products may represent new pharmacologic targets in hematopoietic cell transplantation as well as in the treatment of autoimmune diseases.

scholarly journals Graft versus self (GvS) against T-cell autoantigens is a mechanism of graft–host interaction

2016 ◽  
Vol 113 (48) ◽  
pp. 13827-13832 ◽  
Author(s):  
Nora Mirza ◽  
Manfred Zierhut ◽  
Andreas Korn ◽  
Antje Bornemann ◽  
Wichard Vogel ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Transplantation ◽  
T Cell Activation ◽  
Cell Activation ◽  
Hematopoietic Cell Transplantation ◽  
Cross Reactivity ◽  
Hematopoietic Cell ◽  
T Cell Epitopes ◽  
Graft Versus Host ◽  
Host Interaction

Graft-versus-host disease (GVHD) represents the major nonrelapse complication of allogeneic hematopoietic cell transplantation. Although rare, the CNS and the eye can be affected. In this study, manifestation in the retina as part of the CNS and T-cell epitopes recognized by the allogeneic T cells were evaluated. In 2 of 6 patients with posttransplantation retina diseases and 6 of 22 patients without ocular symptoms, antigen-specific T-cell responses against retina-specific epitopes were observed. No genetic differences between donor and recipient could be identified indicating T-cell activation against self-antigens (graft versus self). Transplantation of a preexisting immunity and cross-reactivity with ubiquitous epitopes was excluded in family donors and healthy individuals. In summary, an immunological reaction against retina cells represents a mechanism of graft-versus-host interaction following hematopoietic cell transplantation.

Rapid establishment of dendritic cell chimerism in allogeneic hematopoietic cell transplant recipients

Blood ◽  
2002 ◽  
Vol 99 (4) ◽  
pp. 1442-1448 ◽  
Author(s):  
Susanne Auffermann-Gretzinger ◽  
Izidore S. Lossos ◽  
Tamara A. Vayntrub ◽  
Wendy Leong ◽  
F. Carl Grumet ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
Cell Activation ◽  
Hematopoietic Cell Transplantation ◽  
De Novo ◽  
Hematopoietic Cell ◽  
Steady Increase ◽  
Cell Transplant ◽  
Allogeneic Hct

Regeneration of hematopoiesis after allogeneic hematopoietic cell transplantation (HCT) involves conversion of the recipient's immune system to donor type. It is likely that distinct cell lineages in the recipient reconstitute at different rates. Dendritic cells (DCs) are a subset of hematopoietic cells that function as a critical component of antigen-specific immune responses because they modulate T-cell activation, as well as induction of tolerance. Mature DCs are transferred with hematopoietic grafts and subsequently arise de novo. Little information exists about engraftment kinetics and turnover of this cell population in patients after allogeneic HCT. This study examined the kinetics of DC chimerism in patients who underwent matched sibling allogeneic HCT. T-cell, B-cell, and myelocytic and monocytic chimerism were also studied. Peripheral blood cells were analyzed at defined intervals after transplantation from 19 patients with various hematologic malignancies after treatment with myeloablative or nonmyeloablative preparatory regimens. Cell subsets were isolated before analysis of chimerism. Despite the heterogeneity of the patient population and preparatory regimens, all showed rapid and consistent development of DC chimerism. By day +14 after transplantation approximately 80% of DCs were of donor origin with steady increase to more than 95% by day +56. Earlier time points were examined in a subgroup of patients who had undergone nonmyeloablative conditioning and transplantation. These data suggest that a major proportion of blood DCs early after transplantation is donor-derived and that donor chimerism develops rapidly. This information has potential implications for manipulation of immune responses after allogeneic HCT.

scholarly journals Immunomodulatory Effects of Polysaccharide from Marine FungusPhoma herbarumYS4108 on T Cells and Dendritic Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Song Chen ◽  
Ran Ding ◽  
Yan Zhou ◽  
Xian Zhang ◽  
Rui Zhu ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Molecular Mechanisms ◽  
Interleukin 12 ◽  
Related Factors ◽  
Knock Out ◽  
Specific Immunity

YCP, as a kind of natural polysaccharides from the mycelium of marine filamentous fungusPhoma herbarumYS4108, has great antitumor potentialviaenhancement of host immune response, but little is known about the molecular mechanisms. In the present study, we mainly focused on the effects and mechanisms of YCP on the specific immunity mediated by dendritic cells (DCs) and T cells. T cell /DC activation-related factors including interferon- (IFN-)γ, interleukin-12 (IL-12), and IL-4 were examined with ELISA. Receptor knock-out mice and fluorescence-activated cell sorting are used to analyze the YCP-binding receptor of T cells and DCs. RT-PCR is utilized to measure MAGE-A3 for analyzing the tumor-specific killing effect. In our study, we demonstrated YCP can provide the second signal for T cell activation, proliferation, and IFN-γproduction through binding to toll-like receptor- (TLR-) 2 and TLR-4. YCP could effectively promote IL-12 secretion and expression of markers (CD80, CD86, and MHC II)viaTLR-4 on DCs. Antigen-specific immunity against mouse melanoma cells was strengthened through the activation of T cells and the enhancement of capacity of DCs by YCP. The data supported that YCP can exhibit specific immunomodulatory capacity mediated by T cells and DCs.

scholarly journals The Pulmonary Metatranscriptome Prior to Pediatric Hematopoietic Cell Transplantation Identifies Post-HCT Lung Injury

Blood ◽  
2020 ◽  
Author(s):  
Matt S Zinter ◽  
Caroline Lindemans ◽  
Birgitta Versluys ◽  
Madeline Y Mayday ◽  
Sara Sunshine ◽  
...  
Keyword(s):  
Gene Expression ◽  
Lung Injury ◽  
Cell Transplantation ◽  
T Cell Activation ◽  
Hematopoietic Cell Transplantation ◽  
Cellular Adhesion ◽  
Hematopoietic Cell ◽  
Epidermal Differentiation ◽  
Term Survival ◽  
Targeted Interventions

Lung injury after pediatric allogeneic hematopoietic cell transplantation (HCT) is a common and disastrous complication that threatens long-term survival. In order to develop strategies to prevent lung injury, novel tools are first needed to comprehensively assess lung health in HCT candidates. Therefore, this study analyzed biospecimens from 181 pediatric HCT candidates who underwent routine pre-HCT bronchoalveolar lavage (BAL) at the University Medical Center in Utrecht, the Netherlands between 2005-2016. BAL fluid underwent metatranscriptomic sequencing of microbial and human RNA and unsupervised clustering and generalized linear models were used to associate microbiome-gene expression data with the development of post-HCT lung injury. Microbe-gene correlations were validated using a geographically distinct cohort of 18 pediatric HCT candidates. The cumulative incidence of post-HCT lung injury varied significantly according to four pre-HCT pulmonary metatranscriptome clusters, with the highest incidence observed in children with pre-HCT viral enrichment and innate immune activation and in children with profound microbial depletion and concomitant NK/T-cell activation (p<0.001). In contrast, children with pre-HCT pulmonary metatranscriptomes containing diverse oropharyngeal taxa and lacking inflammation rarely developed post-HCT lung injury. In addition, activation of epithelial-epidermal differentiation, mucous production, and cellular adhesion were associated with fatal post-HCT lung injury. In a separate validation cohort, associations between pulmonary respiratory viral load, oropharyngeal taxa, and pulmonary gene expression were recapitulated; the association with post-HCT lung injury needs to be validated in an independent cohort. This analysis suggests that assessment of the pre-HCT BAL fluid may identify high-risk pediatric HCT candidates who may benefit from pathobiology-targeted interventions.

scholarly journals Ubiquitination in T-Cell Activation and Checkpoint Inhibition: New Avenues for Targeted Cancer Immunotherapy

2021 ◽  
Vol 22 (19) ◽  
pp. 10800
Author(s):  
Shubhangi Gavali ◽  
Jianing Liu ◽  
Xinyi Li ◽  
Magdalena Paolino
Keyword(s):  
T Cell ◽  
Patient Outcomes ◽  
T Cell Activation ◽  
Cell Activation ◽  
Molecular Mechanisms ◽  
Cancer Therapeutics ◽  
Patient Treatment ◽  
Functional Roles ◽  
Protein Ubiquitination ◽  
Fine Tune

The advent of T-cell-based immunotherapy has remarkably transformed cancer patient treatment. Despite their success, the currently approved immunotherapeutic protocols still encounter limitations, cause toxicity, and give disparate patient outcomes. Thus, a deeper understanding of the molecular mechanisms of T-cell activation and inhibition is much needed to rationally expand targets and possibilities to improve immunotherapies. Protein ubiquitination downstream of immune signaling pathways is essential to fine-tune virtually all immune responses, in particular, the positive and negative regulation of T-cell activation. Numerous studies have demonstrated that deregulation of ubiquitin-dependent pathways can significantly alter T-cell activation and enhance antitumor responses. Consequently, researchers in academia and industry are actively developing technologies to selectively exploit ubiquitin-related enzymes for cancer therapeutics. In this review, we discuss the molecular and functional roles of ubiquitination in key T-cell activation and checkpoint inhibitory pathways to highlight the vast possibilities that targeting ubiquitination offers for advancing T-cell-based immunotherapies.

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