Project description:The memory CD8 T cell pool must select for high-affinity clones to efficiently counter re-infection yet must retain a level of clonal diversity to allow recognition of pathogens with mutated immuno-dominant epitopes. How this is mediated is unclear, especially in the context of a selective drive for antigen-affinity. We find that low-affinity memory exclusively depends on the transcription factor Eomes in the first days after antigen encounter. Eomes is induced at low activating signal strength and directly drives transcription of the pro-survival protein Bcl-2. At higher signal intensity T-bet is induced which suppresses Bcl-2, generating a survival advantage for low-affinity cells. High-affinity cells form memory independent of Eomes and have a proliferative advantage over low-affinity cells, which compensates for their survival deficit. Thus, we demonstrate on a molecular level how sufficient diversity of the memory pool is established in an environment of affinity-based selection.
Project description:To understand the impact of TCR affinity during priming on memory formation, we performed transcriptional profiling of OT-1 cells at different time points after stimulation with high- or low-affinity ligands. Our findings indicate that low-affinity stimulaation is associated with earlier memory formation.
Project description:Gene expression analysis performed on FACS sort purified GC LZ and DZ cells of either high or low affinity to identify unique gene signatures. Analysis revealed distinct transcription patterns.
Project description:Regulatory T cell (Treg) impairment is a common denominator of autoimmune pathologies. Despite the extensive characterization of Treg cell phenotype in autoimmunity, the molecular mechanisms underlying their deterioration remain ill defined. To investigate Treg dysfunction during autoimmunity we performed transcriptomic analysis of CD4+CD25highCD127- Treg cells from peripheral blood of patients with autoimmunity.
Project description:We have defined the tumor and tumor suppressor signature for Meis1 and Prep1 (pKnox1), respectively, using ChIP-seq and RNA-seq in a cell system in which tumor suppressor Prep1 and oncogene Meis1 compete for tumorigenesis [GSE54221; GSE58802]. In this paper we report that the number of Meis1 or Prep1 DNA binding sites increases linearly with the level of expression of the two transcription factors. Overexpression of Meis1 induces tumors. At the molecular level it modifies the DNA target specificity by increasing the number of low-affinity binding sites, which results in a different choice of consensus sequences with predominance of sites normally bound by the AP1 transcription factor family. Upon concomitant overexpression of Prep1 and Meis1 tumorigenesis is inhibited. Prep1 dominates over Meis1 not only because it partially decreases Meis1 protein level but also because it prevents the binding to a substantial fraction of the low affinity binding sites. Overall, overexpression of Prep1 reverses the nature of the bound and regulated genes from stimulatory to inhibitory of signal transduction and transcription, which suppresses tumorigenesis. By identifying the Meis1 tumor signature, specific relevant signaling pathways are identified. In line with these results, tumorigenic Meis1-overexpressing cells are uniquely hypersensitive to inhibitors of the MAPK/Akt pathways. Examination of Prep1 and Meis1 in five cell type
Project description:The gastrointestinal ecosystem is a highly complex environment with a profound influence on human health. Inflammation in the gut, linked to an altered gut microbiome has been associated with the development of multiple human conditions including type 1 diabetes (T1D). Viruses infecting the gastrointestinal tract, especially enteroviruses, are also thought to play an important role in T1D pathogenesis possibly via overlapping mechanisms. Here, we apply an integrative approach to combine comprehensive faecal virome, microbiome and metaproteome data sampled before and at the onset of islet autoimmunity in 40 children. We show strong age and antibody related effects across the datasets. Mastadenovirus infection was associated with profound functional changes in the faecal metaproteome. Multiomic factor analysis modelling revealed proteins associated with carbohydrate transport from the genus Faecalibacterium were associated with islet autoimmunity. These findings demonstrate functional remodelling of the gut microbiota accompanies both islet autoimmunity and viral infection.