The Liston laboratory works on regulatory T cells. These are a type of white blood cell that act to suppress the rest of the immune response, preventing spontaneous autoimmune disease and acting as a rheostat to control just how active our immune system is. The number of these cells in our blood goes up as we get old, which may contribute to the immune-suppressed state of older persons. We seek to understand these cells, using both patient material and mouse models, so that we can harness their power to fine-tune the immune system for healthy ageing.
Regulatory T cells (T) control adaptive immunity and restrain type 2 inflammation in allergic disease. Interleukin-33 promotes the expansion of tissue-resident T and group 2 innate lymphoid cells (ILC2s); however, how T locally coordinate their function within the inflammatory niche is not understood. Here, we show that ILC2s are critical orchestrators of T function. Using spatial, cellular, and molecular profiling of the type 2 inflamed niche, we found that ILC2s and T engage in a direct (OX40L-OX40) and chemotaxis-dependent (CCL1-CCR8) cellular dialogue that enforces the local accumulation of Gata3 T, which are transcriptionally and functionally adapted to the type 2 environment. Genetic interruption of ILC2-T communication resulted in uncontrolled type 2 lung inflammation after allergen exposure. Mechanistically, we found that Gata3 T can modulate the local bioavailability of the costimulatory molecule OX40L, which subsequently controlled effector memory T helper 2 cell numbers. Hence, ILC2-T interactions represent a critical feedback mechanism to control adaptive type 2 immunity.
Microbiome research has gained much attention in recent years as the importance of gut microbiota in regulating host health becomes increasingly evident. However, the impact of radiation on the microbiota in the murine bone marrow transplantation model is still poorly understood. In this paper, we present key findings from our study on how radiation, followed by bone marrow transplantation with or without T cell depletion, impacts the microbiota in the ileum and caecum. Our findings show that radiation has different effects on the microbiota of the two intestinal regions, with the caecum showing increased interindividual variation, suggesting an impaired ability of the host to regulate microbial symbionts, consistent with the Anna Karenina principle. Additionally, we observed changes in the ileum composition, including an increase in bacterial taxa that are important modulators of host health, such as and . In contrast, radiation in the caecum was associated with an increased abundance of several common commensal taxa in the gut, including and . Finally, we found that high doses of radiation had more substantial effects on the caecal microbiota of the T-cell-depleted group than that of the non-T-cell-depleted group. Overall, our results contribute to a better understanding of the complex relationship between radiation and the gut microbiota in the context of bone marrow transplantation and highlight the importance of considering different intestinal regions when studying microbiome responses to environmental stressors.
The tissues are the site of many important immunological reactions, yet how the immune system is controlled at these sites remains opaque. Recent studies have identified Foxp3 regulatory T (Treg) cells in non-lymphoid tissues with unique characteristics compared with lymphoid Treg cells. However, tissue Treg cells have not been considered holistically across tissues. Here, we performed a systematic analysis of the Treg cell population residing in non-lymphoid organs throughout the body, revealing shared phenotypes, transient residency, and common molecular dependencies. Tissue Treg cells from different non-lymphoid organs shared T cell receptor (TCR) sequences, with functional capacity to drive multi-tissue Treg cell entry and were tissue-agnostic on tissue homing. Together, these results demonstrate that the tissue-resident Treg cell pool in most non-lymphoid organs, other than the gut, is largely constituted by broadly self-reactive Treg cells, characterized by transient multi-tissue migration. This work suggests common regulatory mechanisms may allow pan-tissue Treg cells to safeguard homeostasis across the body.