ABSTRACT: Repertoire analysis of γδ T cells in the chicken enables functional annotation of the genomic region revealing highly variable pan-tissue TCR gamma V gene usage as well as identifying public and private repertoires.
Project description:The murine thymus produces discrete γδ T cell subsets making either IFN-γ or IL-17, but the role of the TCR in this developmental process remains controversial. Here we generated a non-transgenic and polyclonal model of reduced TCR expression and signal strength selectively on γδ T cells. Mice haploinsufficient for both CD3γ and CD3δ (CD3DH) showed normal αβ thymocyte subsets but specific defects in γδ T cell development, namely impaired differentiation of IL-17-producing embryonic Vγ6+ (but not adult Vγ4+) γδ T cells and a marked depletion of IFN-γ-producing CD122+ NK1.1+ (Vγ1-biased) γδ T cells throughout life. As result, adult CD3DH mice showed defective peripheral IFN-γ responses and were resistant to experimental cerebral malaria. Thus, strong TCR signaling is required within specific developmental windows with distinct Vγ usage and differential cytokine production by effector γδ T cell subsets.
Project description:Developmental thymic waves of innate-like and adaptive-like gd T cells have been described, but the current understanding of γδ T cell development is mainly limited to mouse models. Here, we combined single cell (sc) RNA gene expression and sc γδ T cell receptor (TCR) sequencing on fetal and pediatric γδ thymocytes in order to understand the ontogeny of human γδ T cells. Mature fetal γδ thymocytes were committed to either a type 1, a type 3 or type 2-like effector fate, independent from γδ T cell subset type (Vγ9Vδ2 vs nonVγ9Vδ2), and were enriched for public CDR3 features upon maturation. Strikingly, type 1, type 3 and type 2 cells expressed different CDR3 sequences and followed distinct developmental trajectories. In contrast, the pediatric thymus generated only a small effector subset that was highly biased towards Vγ9Vδ2 TCR usage and showed a mixed type 1/type 3 effector profile. Thus, our combined dataset of gene expression and detailed TCR information at the single-cell level defines γδ thymocyte development in human and provides a resource for further study.
Project description:γδ T cells represent a substantial fraction of intestinal lymphocytes at homeostasis, but also constitute a major lymphocyte population infiltrating colorectal cancers (CRC), albeit their role in CRC remains unclear. Using human CRC samples and murine CRC models, we found that most γδ T cells in pre- or non-tumor colon exhibit cytotoxic markers while tumor-infiltrating γδ T cells express a pro-tumorigenic profile. These contrasting T cell profiles were associated with distinct TCR-Vγδ gene-usage in both mice and humans. Complementary intersectional genetics and antibody-dependent strategies targeting murine γδ T cells enriched in the epithelium at steady state led to heightened tumor development, while targeting γδ subsets that accumulate during CRC resulted in reduced tumor growth. Our results uncover pro- and anti-tumor roles for γδ T cell subsets.
Project description:γδ T-cells form an integral arm of the immune system through their rapid and potent effector functions, and are critical players during both protective and destructive immunity. However, the factors that dictate γδ T-cell functional programming in vivo remain to be fully elucidated. Here, we employed RBPJ-inducible and KN6-transgenic mice to assess the roles of ontogenic timing, T-cell receptor (TCR) signal strength, and Notch signaling in the generation of γδ T-cell functional subsets in vivo. We found skewed generation of Vγ1+ cells toward the PLZF+ γδ T-cell lineage at the fetal stage. Similarly, generation of interleukin (IL)-17 producing γδ T-cells was favored during, although not exclusive to, the fetal stage. Strong TCR signals, in conjunction with Notch, were necessary for the generation of IL-4 producing γδ T-cells. Conversely, weak TCR signals were amenable for the generation of IL-17 producing γδ T-cells, which was Notch-independent. Additionally and surprisingly, Notch signaling was also dispensable for peripheral γδ T-cell IL-17 production. Thus, our results precisely defined the roles of ontogenic timing, TCR signal strength, and Notch signaling in γδ T-cell functional programming in vivo.
Project description:During thymic development, most γδ T cells acquire innate-like characteristics that are critical for their function in tumor surveillance, infectious disease, and tissue repair. The mechanisms, however, that regulate γδ T cell developmental programming remain unclear. Recently, we demonstrated that the SLAM-SAP signaling pathway regulates the development and function of multiple innate-like γδ T cell subsets. Here, we used a single-cell proteogenomics approach to identify SAP-dependent developmental checkpoints and to define the SAP-dependent γδ TCR repertoire. SAP deficiency resulted in both a significant loss of an immatureGzma+Blk+Etv5+Tox2+γδT17 precursor population, and a significant increase inCd4+Cd8+Rorc+Ptcra+Rag1+thymic γδ T cells. SAP-dependent diversion of embryonic day 17 thymic γδ T cell clonotypes into the αβ T cell developmental pathway was associated with a decreased frequency of mature clonotypes in neonatal thymus, and an altered γδ TCR repertoire in the periphery. Finally, we identify TRGV4/TRAV13-4(DV7)-expressing T cells as a novel, SAP-dependent Vγ4 γδT1 subset. Together, the data suggest that SAP-dependent γδ/αβ T cell lineage commitment regulates γδ T cell developmental programming and shapes the γδ TCR repertoire.
Project description:In this work, we studied clonal T-cell repertoires of synovial fluid from a large cohort of SpA patients aiming to characterise the TCR repertoire structure and to identify specific T-cell clonal expansions
Project description:Recent advancements in microfluidics and high-throughput sequencing technologies have enabled recovery of paired heavy- and light- chain of immunoglobulins (Ig) and VDJ- and VJ- chains of T cell receptors (TCR) from thousands of single cells simultaneously. Due to the complexity of these polyclonal receptors, for many species single-cell immune repertoire sequencing assays are not yet commercially available. Rhesus macaques are one of the most well-studied model organisms of the human adaptive immune response; application of these new immune repertoire sequencing assays is highly relevant to vaccine and infectious disease studies. Here we use custom designed primers to target and enrich for every known Ig and TCR chain and isotype in the rhesus macaque animal model. We sequenced more than 110,000 cell barcodes from rhesus macaque repertoires using PBMC, splenocyte, and FACS-sorted T and B cell. We were able to recover every Ig and TCR isotype, measure clonal expansion in proliferating T cells, and pair repertoires with gene expression profiles of single cells. Our results establish the ability to perform single-cell based immune repertoire analysis in rhesus macaque.
