Project description:The maintenance of tissue homeostasis is critically dependent on the function of tissue-resident lymphocytes, including lipid-reactive invariant natural killer T (iNKT) cells. iNKT cells have unique properties according to their tissues of residency, but if and how the tissue environment shapes their antigen specificity remains unknown. By analysing iNKT cells from tissues of mice and humans we demonstrate that their T cell receptor (TCR) repertoire is highly diverse and is distinct for iNKT cells resident in individual tissues resulting in differential lipid-antigen recognition. Within peripheral tissues, the TCR repertoire of iNKT cell recent thymic emigrants is different from that of mature cells, indicating that the iNKT population is shaped after their arrival to the tissues. Accordingly, in homeostatic conditions the repertoire of iNKT cells is modulated by tissue-specific signals that control iNKT cell activation and proliferation resulting in differential clonal expansion found for cells resident in various organs. Moreover, the iNKT cell TCR repertoire changes in response to lipid immunization and is shaped by age and by environmental changes. Thus, post-thymic modification of the iNKT cell TCR repertoire underpins the distinct antigen specificity of iNKT cells residing in peripheral tissues
Project description:T cells bearing gamma delta T cell antigen receptors (TCRs) function in lymphoid stress surveillance. However, the contribution of gamma delta TCRs to such responses is unclear. Here we found that the TCR of a human V gamma4Vdelta5 clone directly bound endothelial protein C receptor (EPCR), which allowed gamma delta T cells to recognize both endothelial cells targeted by cytomegalovirus and epithelial tumors. EPCR is a major histocompatibility complex–like molecule that binds lipids analogously to the antigen-presenting molecule CD1d. However, the V gamma4Vdelta5 TCR bound EPCR independently of lipids, in an antibody-like way. Moreover, the recognition of target cells by gamma delta T cells required a multimolecular stress signature composed of EPCR and costimulatory ligand(s). Our results demonstrate how a gamma delta TCR mediates recognition of broadly stressed human cells by engaging a stress-regulated self antigen. 2E9 is an antibody that blocks gd-TCR recognition of human cells that are the targets of the clone LES. 2E9 also stains cells that are targeted by LES. Therefore, to identify the TCR ligand expressed by 2E9-positive cells, Gene Expression was compared in two cell lines that stain with 2E9 (K562 and U937) versus two cell lines that do not (Hutu80 and Huh7).
Project description:T cells bearing gamma delta T cell antigen receptors (TCRs) function in lymphoid stress surveillance. However, the contribution of gamma delta TCRs to such responses is unclear. Here we found that the TCR of a human V gamma4Vdelta5 clone directly bound endothelial protein C receptor (EPCR), which allowed gamma delta T cells to recognize both endothelial cells targeted by cytomegalovirus and epithelial tumors. EPCR is a major histocompatibility complex–like molecule that binds lipids analogously to the antigen-presenting molecule CD1d. However, the V gamma4Vdelta5 TCR bound EPCR independently of lipids, in an antibody-like way. Moreover, the recognition of target cells by gamma delta T cells required a multimolecular stress signature composed of EPCR and costimulatory ligand(s). Our results demonstrate how a gamma delta TCR mediates recognition of broadly stressed human cells by engaging a stress-regulated self antigen.
Project description:T cells are required for protective immunity against Mycobacterium tuberculosis. We recently described a cohort of Ugandan household contacts of tuberculosis cases who appear to “resist” M. tuberculosis infection (resisters; RSTRs) and showed that these individuals harbor IFN-γ–independent T cell responses to M. tuberculosis–specific peptide antigens. However, T cells also recognize nonprotein antigens via antigen-presenting systems that are independent of genetic background, known as donor-unrestricted T cells (DURTs). We used tetramer staining and flow cytometry to characterize the association between DURTs and “resistance” to M. tuberculosis infection. Peripheral frequencies of most DURT subsets were comparable between RSTRs and latently infected controls (LTBIs). However, we observed a 1.65-fold increase in frequency of MR1-restricted T (MR1T) cells among RSTRs in comparison with LTBIs. Single-cell RNA sequencing of 18,251 MR1T cells sorted from 8 donors revealed 5,150 clonotypes that expressed a common transcriptional program, the majority of which were private. Sequencing of the T cell receptor α/T cell receptor δ (TCRα/δ) repertoire revealed several DURT clonotypes were expanded among RSTRs, including 2 MR1T clonotypes that recognized mycobacteria-infected cells in a TCR-dependent manner. Overall, our data reveal unexpected donor-specific diversity in the TCR repertoire of human MR1T cells as well as associations between mycobacteria-reactive MR1T clonotypes and resistance to M. tuberculosis infection.
Project description:The beta2 integrin subunit (CD18) is thought to regulate gamma delta T cells in vivo. The objective of this study was to determine the gene expression changes mediated by loss of CD18 in lung gamma delta T cells. Single cell RNA sequencing was performed on gamma delta T cells (CD3+ gamma delta TCR+) isolated from the lungs of wild type C57BL/6 mice (N=2) and CD18 knockout (Itgb2-/-) mice (N=1).
Project description:Background: Malignant clones of primary cutaneous T-cell lymphomas (CTCL) can show a CD4+, CD8+ or T-cell receptor γδ+ phenotype, but their individual impact on tumor biology and skin lesion formation remains ill-defined. We perform a comprehensive molecular characterization of CD4+ vs. CD8+ and TCR-γ/δ+ CTCL lesions. Methods: We performed scRNA-seq of 18 CTCL skin biopsies to compare classic CD4+ advanced-stage mycosis fungoides (MF) with TCR-γ/δ+ MF and primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma (Berti’s lymphoma). Results: Malignant clones of TCR-γ/δ+ MF and Berti’s lymphoma showed similar clustering patterns distinct from CD4+ MF, along with increased expression of cytotoxic markers such as NKG7, CTSW, GZMA, and GZMM. Only advanced-stage CD4+MF clones expressed central memory T-cell markers (SELL, CCR7, LEF1), alongside B1/B2 blood involvement, whereas TCR-γ/δ+ MF and Berti’s lymphoma harbored a more tissue-resident phenotype (CD69, CXCR4, NR4A1) without detectable cells in the blood. CD4+ MF and TCR-γ/δ+ MF skin lesions harbored strong type 2 immune activation across myeloid cells, while Berti’s lymphoma was more skewed towards type 1 immune responses. Both CD4+ MF and TCR-γ/δ+ MF lesions showed upregulation of keratinocyte hyperactivation markers such as S100As and KRT16 genes. This increase was entirely absent in Berti’s lymphoma, possibly reflecting an aberrant keratinocyte response to invading tumor cells, that could contribute to the formation of the typical ulcero-necrotic lesions within this entity. Conclusions: Our scRNAseq profiling study reveals specific molecular patterns associated with distinct CTCL subtypes.