Project description:The origin and function of human double negative (DN) TCR-alpha/beta T cells is unknown. They are thought to contribute to the pathogenesis of systemic lupus erythematosus because they expand and accumulate in inflamed organs. Here we provide evidence that human TCR-alpha/beta CD4- CD8- DN T cells derive exclusively from activated CD8+ T cells. Freshly isolated TCR-alpha/beta DN T cells display a distinct gene expression and cytokine production profile. DN cells isolated from peripheral blood as well as DN cells derived in vitro from CD8+ T cells, produce a defined array of pro-inflammatory mediators that includes IL-1, IL-17, IFN-gama, CXCL3, and CXCL2. These results indicate that, upon activation, CD8+ T cells have the capacity to acquire a distinct phenotype that grants them inflammatory capacity. TCR-alpha-beta+ CD25- T cells from healthy human individuals were sorted into CD4+, CD8+, and CD4-CD8- T cells. Cell lysis and RNA extraction was performed immediately. RNA from each cell subset was pooled.
Project description:We have performed whole genome expression arrays covering over 47000 transcripts comparing the transcriptional profile of NKp80+ to NKp80- CD8+ CCR7- alpha beta T cells. A highly similar global gene expression profile was observed between both memory phenotype T cell subsets. Interestingly, the majority of differentially expressed genes are immune-associated. NKp80+ cells contained markedly increased levels of transcripts encoding for MHC class I and II molecules and for numerous members of the KIR family. Also other NK-related transcripts were more abundantly expressed in the NKp80+ subset. With regards to cytokines, chemokines and their receptors, transcripts important for homeostasis and proliferation are expressed differently. Also transcripts encoding for adhesion molecules are present at different levels in both T cell subsets. Further cytotoxic effector molecules are expressed differently. Experiment Overall Design: We used CD4, CD14 depleted PBMCs pooled from six healthy donors. Following FACS sorting of NKp80+ CD8+ CCR7- alpha beta T cells and NKp80- cells, respectively, transcript levels of both subsets have been compared on human whole genome expression arrays.
Project description:The origin and function of human double negative (DN) TCR-alpha/beta T cells is unknown. They are thought to contribute to the pathogenesis of systemic lupus erythematosus because they expand and accumulate in inflamed organs. Here we provide evidence that human TCR-alpha/beta CD4- CD8- DN T cells derive exclusively from activated CD8+ T cells. Freshly isolated TCR-alpha/beta DN T cells display a distinct gene expression and cytokine production profile. DN cells isolated from peripheral blood as well as DN cells derived in vitro from CD8+ T cells, produce a defined array of pro-inflammatory mediators that includes IL-1, IL-17, IFN-gama, CXCL3, and CXCL2. These results indicate that, upon activation, CD8+ T cells have the capacity to acquire a distinct phenotype that grants them inflammatory capacity.
Project description:The aim of this study was to quantify the impact of NOD genetic vatiation on the transcriptional programs induced by the alpha beta-TCR at the DN to DP transition in the BDC2.5 TCR Tg model CD4 and CD8-complement mediated depletion followed by FACS Experiment type: BDC2.5 TCR Tg or polyclonal B6g7 versus NOD
Project description:Conventional CD4 and CD8 single positive T cell lineages constitute the main differentiation pathway in the thymus. In human thymus, a minor TCRαβ differentiation pathway diverges from the early double positive stage, consisting of CD10+ PD-1+ cells. These cells are phenotypically and functionally similar to murine agonist-selected intraepithelial T lymphocyte precursors (IELps) which home to the small intestine. Here, the progeny of the human agonist-selected IEL lineage was identified in antigen-inexperienced cord blood (CB) with a polyclonal T cell receptor (TCR) repertoire exhibiting a bias towards early TCR alpha chain rearrangements and elevated autoreactive indices. Single-cell RNA sequencing allowed further delineation of this unconventional lineage in CB. Trajectory analysis, along with TCR repertoire analysis, transcriptomics and proteomics, suggests a precursor-progeny relationship with the thymic IELps. The distinct, heterogeneous CB population can now be defined as CD3+ TCRαβ+ CD4- CCR7- CD26-. Besides recent thymic emigrants, this population also consists of newly identified effector clusters and previously described populations: the suppressive NK receptor expressing CD8+ Treg population, the KIR/NKG2A+ EOMES+ virtual memory population and the CD8αα+ T cell populations. The population shows a discriminating stable HELIOS expression and is exclusively able to downregulate CD8β expression, resulting in double negative T cells. The functional properties of this population suggest that the cells expand on inflammatory cues and exert cytotoxic and proinflammatory activity.
Project description:Type 1 diabetes (T1D) is an autoimmune disorder defined by CD8 T cell-mediated destruction of pancreatic β cells. Our previous work has shown that diabetogenic CD8 T cells in the islets of the non-obese diabetic (NOD) mouse model of T1D are phenotypically heterogenous, but CD8 T cell clonal heterogeneity in this model remains relatively unexplored. Here, we use paired single-cell RNA sequencing (scRNA-seq) and single-cell T cell receptor sequencing (scTCR-seq) to characterize autoreactive CD8 T cells from the islets and spleens of NOD mice. Clonal analysis of scTCR-seq data demonstrates that CD8 T cells targeting the immunodominant β cell epitope IGRP206-214 exhibit highly restricted TCR gene usage, with over 70% of IGRP206-214-reactive cells utilizing the same TCR V alpha, J alpha, and V beta genes. Despite this, we observe only 5% overlap of IGRP206-214-reactive CD8 T cell clones between two groups of 10 NOD mice, demonstrating the immense TCR heterogeneity generated by junctional diversity during V(D)J recombination. scRNA-seq identifies two new clusters of autoreactive CD8 T cells in the islets and six clusters of diabetogenic CD8 T cells in the spleen, including multiple memory-like clusters and a population of exhausted cells. Strong clonal overlap between IGRP206-214-reactive CD8 T cells in the islets and spleen suggests that these cells may exit the islets and enter the peripheral circulation. Finally, we identify correlations between TCR J beta gene usage, which is less restricted than that of other TCR genes, and CD8 T cell clonal expansion as well as effector fate. Collectively, our work demonstrates that IGRP206-214-specific CD8 T cells are phenotypically heterogeneous but clonally similar, raising the possibility of selectively targeting either conserved or divergent TCR structures of these cells for therapeutic benefit.
Project description:Human CD8+ T cells are functionally heterogeneous and can be divided into distinct subsets according to CCR7 and CD45RA expression levels. Among the subsets, CCR7-CD45RA+ CD8+ T cells are considered to be terminally differentiated cells and designated as Temra. Temra show attenuated ability to proliferate and produce IFN-gamma in response to TCR stimulation, while Temra show improved function after IL-15 treatment. To clarify the transcriptional signatures induced by the stimulations, Temra were purified using flow cytometry, stimulated with IL-15 or with anti-CD3/CD28 (TCR stimulation), or cultured without stimulation for 2 days, and subjected to microarray analysis.