Trigger-happy resident memory CD4+ T cells inhabit the human lungs.
Ontology highlight
ABSTRACT: Resident memory T-cells (TRM) reside in the lung epithelium and mediate protective immunity against respiratory pathogens. While lung CD8+ TRM have been extensively characterized, the properties of CD4+ TRM remain unclear. Here we determined the transcriptional signature of CD4+ TRM, identified by the expression of CD103, retrieved from human lung resection material. Various tissue homing molecules were specifically upregulated on CD4+ TRM, while expression of tissue egress and lymph node homing molecules were low. CD103+ TRM expressed low levels of T-bet, only a small portion expressed Eomes, and while the mRNA levels for Hobit were increased, protein expression was absent. On the other hand, the CD103+ TRM showed a Notch signature. CD4+CD103+ TRM constitutively expressed high transcript levels of numerous cytotoxic mediators, which was functionally reflected by a fast recall response, magnitude of cytokine production, and a high degree of polyfunctionality. Interestingly, the superior cytokine production appears to be due to an accessible IFNγ locus and was partially due to rapid translation of preformed mRNA. Our studies provide a molecular understanding of the maintenance and potential function of CD4+ TRM in the human lung. Understanding the specific properties of CD4+ TRM is required to rationally improve vaccine design.
Project description:Current cancer immunotherapies promote recovery of CD103+ tissue-resident memory T cells (Trm) population of the tumor-infiltrating T lymphocytes (TILs). However, not all treated patients exhibit improved anti-tumor immunity and survival, likely due to the immunophenotypical diversity among the CD103+ Trm TILs. Utilising multifaceted proteomics approaches and patients’ clinical analyses, we discovered an unusual subset of CD8+ Trm TILs expressing non-canonical integrin β3 early during T cells activation. The integrin β3 surprisingly heterodimerises with CD103 on T cells, leading to unconventional granulysin-mediated cytotoxicity, elevated alternative bioenergy usage and efficient T cell migration, with minimal overall exhaustion. Importantly, early-stage non-small cell lung carcinoma (NSCLC) patients with enriched presence of integrin β3+CD103+ Trm TILs exhibited better clinical prognosis, with improved T cell immunophenotype, hence confirming the beneficial role of this unusual subset of Trm TILs. These unconventional anti-tumor T cell features provide new avenues and future opportunities for designing better translational immunotherapy strategies.
Project description:Tissue-resident memory CD8+ T cells (TRM) constitute a non-circulating memory T cell subset that provides early protection against re-infection. However, how TRM arise from antigen-triggered T cells has remained unclear. Exploiting the TRM-restricted expression of Hobit, we developed TRM reporter/deleter mice to study TRM differentiation. We found that Hobit was upregulated in a subset of LCMV-specific T cells located within peripheral tissues during the effector phase of the immune response. These Hobit+ effector T cells were identified as TRM precursors, given that their depletion substantially decreased TRM development, but not the formation of circulating memory T cells. Adoptive transfer experiments of Hobit+ effector T cells corroborated their biased contribution to the TRM lineage. Transcriptional profiling of Hobit+ effector T cells underlined the early establishment of TRM properties including downregulation of tissue exit receptors and upregulation of TRM-associated molecules. Importantly, we identified Eomes as a key factor instructing the early bifurcation of circulating and resident lineages. These findings establish that commitment of TRM occurs early in antigen-driven T cell differentiation and reveal the molecular mechanisms underlying this differentiation pathway.
Project description:Transforming growth factor β (TGFβ) is a morphogenic protein that augments antiviral immunity by altering the functional properties of pathogen-specific memory CD8 T cells. During infection, TGFβ inhibits formation of effector (TEFF) and circulating memory CD8 T cells, while encouraging tissue-resident memory CD8 T cells (TRM) to settle in peripheral tissues. SMAD proteins are signaling intermediates that are used by members of the TGF cytokine family to modify gene expression. Using RNA-sequencing we determined that SMAD4 altered the transcriptional profile of antiviral CTLs during respiratory infection. Our data show that SMAD4 and TGFβ use alternate signaling pathways to cooperatively regulate a collection of genes that determine whether pathogen-specific memory CD8 T cells localize in peripheral or lymphoid tissues. During infection, SMAD4 acts independently of TGF to inhibit TRM development, while inducing genes that support formation of circulating memory CD8 T cells. The genes that are modulated by SMAD4 include several homing receptors (CD103, KLRG1 and CD62L) and transcription factors (Hobit and EOMES) that support memory formation.
Project description:A specialized population of memory CD8+ T-cells resides in the epithelium of the respiratory tract to maintain protection against recurring infections. These cells express CD69 and the integrin αβ7 (CD103) and correspond to tissue resident memory T-cells (TRM) also described in intestine, liver and brain. A less well characterized population of CD103- CD8+ T-cells also resides in lungs and expresses markers characteristic of effector memory T-cells (TEM). We determined the transcriptional profiles of these memory CD8+ T-cell subsets retrieved from human lung resection samples and compared these with corresponding T-cell populations from peripheral blood of the same individuals. Our results demonstrate that each of the populations exhibits a distinct transcriptional identity. We found that the lung environment has a major impact on gene expression profiles. Thus, transcriptomes from CD103+ and CD103- subsets from lungs are much more resemblant to one another than to those from CD103+ or CD103- memory CD8+ T-cells from blood. TRM express specific sets of chemokine receptors, in accordance with their unique migratory properties. Furthermore, these cells constitutively express cytokine and cytotoxic genes for immediate effector function and chemokines to attract auxiliary immune cells. At the same time, multiple genes encoding inhibitory regulators are also expressed. This suggests that rapid ability to unleash effector functions is counterbalanced by programmed restraint, a combination that may be critical in the exposed but delicate tissue of the lung. Comprehensive sets of transcription factors were identified that characterize the memory CD8+ populations in the lungs. Prominent among these were components of the Notch pathway. Using mice genetically lacking expression of the NOTCH1 and NOTCH2 receptors in T-cells, we demonstrated that Notch controls both the number of lung TRM as well as the function of lung TEM. Our data illustrate the adaptation of lung resident T-cells to the requirements of the respiratory epithelial environment. Defining the molecular imprinting of these cells is important for rational vaccine design and may help to improve the properties of T-cells for adoptive cellular therapy. Material was collected from a total of 6 subjects. Three patients underwent a lobectomy for a peripheral primary lung tumor and three received lung transplantation because of end-stage pulmonary disease (COPD). Lung mononuclear cells where isolated after digestion of the partial or complete human lung resection material. Paired peripheral blood mononuclear cells were also isolated. CD8+CD16-CD56- T-cells were sorted for expression of CD103 (ITGAE). Lung and blood derived CD103+ and CD103- T-cell fractions were directly lysed after FACS sorting or stimulated overnight with antiCD3/28 beads. Due to the low frequency of resting (non-stimulated) CD103+ T-cells in peripheral blood this subset was obtained from five non-related buffy coat donors. RNA was isolated from 36 sorted cell samples and hybridized on Illumina HumanHT-12 V4.0 microarrays. Eight microarray samples (including two samples from the buffy coat donors) were excluded after hybridization since their average signal was too low.
Project description:Tissue-resident memory T (TRM) cells are crucial mediators of adaptive immunity in non-lymphoid tissues. However, the functional heterogeneity and pathogenic roles of CD4+ TRM cells that reside within chronic inflammatory lesions remain unknown. We found that CD69hiCD103low CD4+ TRM cells produced effector cytokines and promoted the inflammation and fibrotic responses induced by chronic exposure to Aspergillus fumigatus. Simultaneously, immunosuppressive CD69hiCD103hiFoxp3+ CD4+ regulatory T (Treg) cells were induced and constrained the ability of pathogenic CD103low TRM cells to cause fibrosis. Thus, lung tissue-resident CD4+ T cells play crucial roles in the pathology of chronic lung inflammation, and CD103 expression defines pathogenic effector and immunosuppressive tissue-resident cell subpopulations in the inflamed lung.
Project description:CD8 tissue-resident memory T (TRM) cells provide front-line protection at barrier tissues; however, mechanisms regulating TRM cell development are not completely understood. Priming dictates the migration of effector T cells to the tissue, while factors in the tissue induce in situ TRM cell differentiation. Whether priming also regulates in situ TRM cell differentiation uncoupled from migration is unclear. Here, we demonstrate that T cell priming in the mesenteric lymph nodes (MLN) regulates CD103+ TRM cell differentiation in the intestine. In contrast, T cells primed in the spleen were impaired in the ability to differentiate into CD103+ TRM cells after entry into the intestine. MLN priming initiated a CD103+ TRM cell gene signature and licensed rapid CD103+ TRM cell differentiation in response to factors in the intestine. Licensing was regulated by retinoic acid signaling and primarily driven by factors other than CCR9 expression and CCR9-mediated gut homing. Thus, the MLN is specialized to promote intestinal CD103+ CD8 TRM cell development by licensing in situ differentiation.
Project description:Tissue-resident memory T cells (TRM) persist locally in non-lymphoid tissues where they provide front-line defense against recurring insults. TRM at barrier surfaces express the markers CD103 and/or CD69 which function to retain them in epithelial tissues. In humans, neither the long-term migratory behavior of TRM nor their ability to re-enter the circulation and potentially migrate to distant tissue sites have been investigated. Using tissue explant cultures, we found that CD4+CD69+CD103+ TRM in human skin can downregulate CD69 and exit the tissue. Additionally, we identified a skin-tropic CD4+CD69-CD103+ population in human lymph and blood that is transcriptionally, functionally and clonally related to the CD4+CD69+CD103+ TRM population in the skin. Using a skin xenograft model, we confirmed that a fraction of the human cutaneous CD4+CD103+ TRM population can re-enter circulation, and migrate to secondary human skin sites where they re-assume a TRM phenotype. Thus, our data challenge current concepts regarding the strict tissue compartmentalization of CD4+ T cell memory in humans.
Project description:Tissue-resident memory T (TRM) cells provide key adaptive immune responses in infection, cancer, and autoimmunity. However transcriptional heterogeneity of human intestinal TRM cells remains undefined. Here, we investigated transcriptional and functional heterogeneity of human TRM cells through study of donor-derived intestinal TRM cells from intestinal transplant recipients. Single-cell transcriptional profiling identified two distinct transcriptional states of CD8+ TRM cells, delineated by ITGAE and ITGB2 expression. We defined a transcriptional signature discriminating these two CD8+ populations, including differential expression of cytotoxicity- and residency-associated genes. Flow cytometry of recipient-derived cells infiltrating the graft and lymphocytes from healthy gut confirmed the two CD8+ TRM phenotypes. CD103+ CD8+ TRM cells produced IL-2, and demonstrated greater polyfunctional cytokine production, while β2-integrin+ CD69+ CD103- TRM cells had higher granzyme expression. Phenotypic and functional analysis of intestinal CD4+ T cells identified many parallels, including a distinct β2-integrin+ population. Together, these results describe the transcriptional, phenotypic, and functional heterogeneity of human intestinal CD4+ and CD8+ TRM cells.
Project description:Tissue-resident memory T (TRM) cells provide key adaptive immune responses in infection, cancer, and autoimmunity. However transcriptional heterogeneity of human intestinal TRM cells remains undefined. Here, we investigated transcriptional and functional heterogeneity of human TRM cells through study of donor-derived intestinal TRM cells from intestinal transplant recipients. Single-cell transcriptional profiling identified two distinct transcriptional states of CD8+ TRM cells, delineated by ITGAE and ITGB2 expression. We defined a transcriptional signature discriminating these two CD8+ populations, including differential expression of cytotoxicity- and residency-associated genes. Flow cytometry of recipient-derived cells infiltrating the graft and lymphocytes from healthy gut confirmed the two CD8+ TRM phenotypes. CD103+ CD8+ TRM cells produced IL-2, and demonstrated greater polyfunctional cytokine production, while β2-integrin+ CD69+ CD103- TRM cells had higher granzyme expression. Phenotypic and functional analysis of intestinal CD4+ T cells identified many parallels, including a distinct β2-integrin+ population. Together, these results describe the transcriptional, phenotypic, and functional heterogeneity of human intestinal CD4+ and CD8+ TRM cells.
Project description:A specialized population of memory CD8+ T-cells resides in the epithelium of the respiratory tract to maintain protection against recurring infections. These cells express CD69 and the integrin αβ7 (CD103) and correspond to tissue resident memory T-cells (TRM) also described in intestine, liver and brain. A less well characterized population of CD103- CD8+ T-cells also resides in lungs and expresses markers characteristic of effector memory T-cells (TEM). We determined the transcriptional profiles of these memory CD8+ T-cell subsets retrieved from human lung resection samples and compared these with corresponding T-cell populations from peripheral blood of the same individuals. Our results demonstrate that each of the populations exhibits a distinct transcriptional identity. We found that the lung environment has a major impact on gene expression profiles. Thus, transcriptomes from CD103+ and CD103- subsets from lungs are much more resemblant to one another than to those from CD103+ or CD103- memory CD8+ T-cells from blood. TRM express specific sets of chemokine receptors, in accordance with their unique migratory properties. Furthermore, these cells constitutively express cytokine and cytotoxic genes for immediate effector function and chemokines to attract auxiliary immune cells. At the same time, multiple genes encoding inhibitory regulators are also expressed. This suggests that rapid ability to unleash effector functions is counterbalanced by programmed restraint, a combination that may be critical in the exposed but delicate tissue of the lung. Comprehensive sets of transcription factors were identified that characterize the memory CD8+ populations in the lungs. Prominent among these were components of the Notch pathway. Using mice genetically lacking expression of the NOTCH1 and NOTCH2 receptors in T-cells, we demonstrated that Notch controls both the number of lung TRM as well as the function of lung TEM. Our data illustrate the adaptation of lung resident T-cells to the requirements of the respiratory epithelial environment. Defining the molecular imprinting of these cells is important for rational vaccine design and may help to improve the properties of T-cells for adoptive cellular therapy.