Project description:We analyzed the TCRb repertoires of CD4 and CD8 single-positive thymocytes isolated from a pediatric donor, as well as CD4 and CD8 single-positive thymocytes matured in vitro from the double-positive stage in 3D organoid co-culture with iPSC-derived thymic epithelial cells (iTECs). Our analysis shows that iTECs are capable of positively selecting thymocytes with diverse TCR repertoires in vitro.
Project description:Deletion of BTLA up regulates CD5 expression. Higher CD5 expression during thymic selection is associated with increased self-recognition, suggesting that BTLA might be needed early to establish self-tolerance. To investigate whether the regulation of CD5 by BTLA is TCR-repertoire independent, we performed single-cell TCR sequencing in SP CD4 thymocytes from regular B6 and B6 Btla Knock-Out (KO) mice.
Project description:Wild type thymi were transplanted into wild recipients (turnover) or Rag2-/-gc-/- mice (autonomy) and, after 28 days of transplant, thymocytes (double negative 3 and 4, immature CD8 single positive and CD4 CD8 double positive) were sorted and single cell RNAseq and TCR repertoire analysis performed
Project description:The regulation of thymocyte development by RNA-binding proteins (RBPs) is largely unexplored. We identified 642 RBPs in the thymus and focused on Arpp21, which shows selective and dynamic expression in early thymocytes. Arpp21 was downregulated in response to T cell receptor (TCR) and Ca2+ signals. Downregulation required Stim1/Stim2 and CaMK4 expression and involved Arpp21 protein phosphorylation, polyubiquitination and proteasomal degradation. Arpp21 directly bound RNA through its R3H domain, with a preference for uridine-rich motifs, promoting the expression of target mRNAs. Analysis of the Arpp21-bound transcriptome revealed strong interactions with the Rag1 3'-UTR. Arpp21-deficient thymocytes showed reduced Rag1 expression, delayed TCR rearrangement and a less diverse TCR repertoire. This phenotype was recapitulated in Rag1 3'-UTR mutant mice harboring a deletion of the Arpp21 response region. These findings show how thymocyte-specific Arpp21 promotes Rag1 expression to enable TCR repertoire diversity until signals from the TCR terminate Arpp21 and Rag1 activities.
Project description:Temporal analysis of T-cell receptor (TCR) repertoire has been used to monitor treatment-induced changes in antigen-specific T cells in patients with cancer. However, lack of experimental model that allows the temporal analysis of TCR repertoire in same individual in homogeneous population limit the understanding of causal relationship between changes in TCR repertoire and antitumor responses. A bilateral tumor model, in which tumor cells were inoculated into the bilateral backs of mice, can be used for temporal analysis in TCR repertoire. In this study, we examined the prerequisite for this strategy: TCR repertoire are conserved between the bilateral tumor with same growth rate. The bilateral tumors with equivalent tumor size and draining lymph nodes (dLN) were collected 13 days after the tumor inoculation to analyze the TCR repertoire of CD4+ and CD8+ T cells. Most of the tumor-infiltrating T-cell clones were highly conserved between the bilateral tumors, and the extent of clonal expansion was equivalent. In addition, the similarity between bilateral tumors were equivalent to the heterogeneity in one side of the tumor. The similarity of TCR repertoire in the bilateral dLN was markedly lower than that of the tumor, suggesting that tumor-reactive T-cell clones induced independently in each dLN were integrated during recirculation and then infiltrated the tumor. These findings suggest that our bilateral tumor model is suitable for temporal monitoring of TCR repertoire to evaluate temporal and treatment-induced changes in tumor-reactive T-cell clones.
Project description:Screening for mouse cDNA that was highly expressed in positive-selector H-2b AND-TCR-transgenic thymocytes using Affymetrix Murine Genome arrays. Experiment Overall Design: 2 thymocytes, H-2b AND-TCR-transgenic thymocytes and C57BL/6 thymocytes, were analyzed by duplicate hybridization.
Project description:HLA-E molecules can present self and pathogen-derived peptides to both NK-cells and T-cells. T-cells that recognize HLA-E peptides via their T-cell receptor (TCR) are termed donor-unrestricted T-cells due to restricted allelic variation of HLA-E. The composition and repertoire of HLA-E TCRs is not known so far. We performed TCR sequencing on CD8+ T-cells from 21 individuals recognizing HLA-E tetramers (TM) folded with 2 Mtb HLA-E restricted peptides. We sorted HLA-E Mtb TM+ and TMCD8+ T-cells directly ex vivo and performed bulk RNA-sequencing and single cell TCR sequencing. The identified TCR repertoire was diverse and showed no conservation between and within individuals. TCRs selected from our single cell TCR sequencing data could be activated upon HLA-E/peptide stimulation, although not robust, reflecting potentially weak interactions between HLA-E peptide complexes and TCRs. Thus, HLA-E Mtb specific T-cells have a highly diverse TCR repertoire.
Project description:Themis1, a recently described T-lineage specific protein, is essential for thymic positive and negative selection. Although Themis1 has been clearly identified as a component of the T cell antigen receptor (TCR) signalosome, its precise role in TCR signaling remains unclear. Here, we used quantitative proteomic and TCR signaling reporter mice to gain insight into Themis1 signaling function. Mass spectrometry analysis of the Themis1 interactome identified Grb2, SHP1 and Vav1 as the principal interacting partners of Themis1 in thymocytes. The dataset contains mass spectrometry results from the analysis of 6 different kind of AP-MS purifications (based on immunoprecipitation using a Themis1 antibody) starting from the following samples: - thymocytes from WT mice, non stimulated (noted WT NS) - thymocytes from WT mice, stimulated with pervanadate (noted WT P) - thymocytes from GRB2 +/- mice (with decreased expression of GRB2), non stimulated (noted GRB2 NS) - thymocytes from GRB2 +/- mice (with decreased expression of GRB2), stimulated with pervanadate (noted GRB2 P) - thymocytes from Themis1 -/- mice (knock-out for Themis1), non stimulated (noted KO NS) - thymocytes from Themis1 -/- mice (knock-out for Themis1), stimulated with pervanadate (noted KO P) Three biological replicates were prepared for these 6 different conditions (noted, 1,2,3), yielding 18 analyzed samples. Three technical nanoLC-MS runs were acquired for each sample (noted R1, R2, R3), leading to the 54 nanoLC-MS raw files contained in the dataset.