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: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 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:Murine γδ T cells include several effector subsets that fulfil distinct functional roles. In pathological conditions, such as cancer, some γδ T cell subsets are highly protective whereas other subsets may exacerbate disease. γδ T cells are programmed for their effector function during their development in the thymus. Investigations of γδ T cell development have been hampered by the scarcity of surface markers distinguishing different development stages. In this study, we found that addition of CD117, CD200 and CD371 to existing markers, allowed identification of seven distinct development stages (named A, B, C, D, E, F and G) present in both the Vγ1.1+ and Vγ2+ thymocyte subsets. We provide evidence for the existence of three distinct pathways leading to export of γδ T cells, two of which express high levels of CD24. These pathways are dominated by different TCRδ repertoires shaped by TCR signalling or lack thereof. Each pathway express distinct cytokine and transcription factor profiles associated with γδT1, γδNKT and adaptive γδ T cells. Thus, the identification of additional γδ T cell development stages in this study connects three distinct development pathways to the programming of three γδ T cell effector subsets.