Search

International audience; Objectives: In patients with spinal cord injury, spinal cord injury-immune depression syndrome induces pneumonia. We aimed to develop a new spinal cord injury-immune depression syndrome mouse model and to test antiprogrammed cell death 1 therapy. Design: Experimental study. Setting: Research laboratory. Subjects: RjOrl: SWISS and BALB/cJ mice. Interventions: Mouse model of spinal cord injury-immune depression syndrome followed by a methicillin-susceptible Staphylococcus aureus pneumonia. Lung injuries were assessed by histologic analysis. Membrane markers and intracytoplasmic cytokines were assessed by flow cytometry. Cytokine production was assessed by quantitative polymerase chain reaction (messenger RNA) and enzyme-linked immunosorbent assay (protein). Animals were treated with blocking antiprogrammed cell death 1 antibodies (intraperitoneal injection). Measurements and Main Results: Spinal cord injury mice were more susceptible to methicillin-susceptible S. aureus pneumonia (increased mortality rate). An early inflammatory response was observed in spinal cord injury mice characterized in lungs by a decreased percentage of aerated tissue, an increased production of proinflammatory cytokines (tumor necrosis factor-α). In spleen, an increased expression of major histocompatibility complex class II molecules on dendritic cells, and an increased production of pro-inflammatory cytokines (interleukin-12, interferon-γ) was observed. Following this pulmonary and systemic inflammation, spinal cord injury-immune depression syndrome was observed in spleens as acknowledged by a decrease of spleen's weight, a lymphopenia, a decrease of major histocompatibility complex class II expression on dendritic cells. An increase of interleukin-10 production and the increase of a cell exhaustion marker expression, programmed cell death 1 receptor on T-cell were also observed. Blockade of programmed cell death 1 molecules, improved survival of spinal cord injury infected mice and enhanced interferon-γ production by natural killer T cells as well as number of viable CD4 + T cells. Conclusions: This model of spinal cord injury in mice mimics a clinical scenario rendering animals prone to a secondary pneumonia. We show for the first time an acute T-cell exhaustion-like phenomenon following an initial inflammatory response. Finally, inhibition of exhaustion pathway should be considered as a new therapeutic option to overcome spinal cord injury-immune depression syndrome and to decrease the rate of nosocomial pneumonia. (Crit Care Med 2019; 47:e28-e35) Key Words: brain injury; immunosuppression; immunotherapy; programmed cell death 1 receptor; spinal cord injury N osocomial infections are independent risk factors for poor neurologic outcome after motor complete spinal cord injury (SCI) (1). SCI induces a severe initial systemic inflammatory response followed by an intense period of immunosuppression which is recognized as an independent risk factor for infection (1, 2). Studies in human and rodent SCI models have already investigated the specific

Peripheral CD4+CD8+ double positive (DP) T cells are a phenotypically and functionally heterogeneous population depending on their origin and pathologic context. We previously identified among tumour infiltrating lymphocytes in melanoma, a tumour-reactive MHC class-I restricted CD4lowCD8high DP αβ T-cell subpopulation with CD4-like function. In this study, we used an in-depth comparative transriptomic analysis of intra-melanoma DP T cells and CD4 and CD8 single positive (SP) T cells, to better comprehend the origin of this DP phenotype, and define the transcriptomic signature of activated DP T cells. We observed that intra-melanoma DP T cells were transcriptome-wise closer to their CD8 SP T-cell counterparts in terms of number of genes differentially expressed (97 in common with CD8 SP T cells and 15 with CD4 SP T cells) but presented hallmarks of a transition to a CD4-like functional profile (CD40LG) with a decreased cytotoxic signature (KLRC1) in favour of an increased cytokine-receptor interaction signature (IL4, IL24, IL17A…). This unleashed CD4-like program could be the results of the observed unbalanced expression of the THPOK/Runx3 transcription factors in DP T cells. Overall, this study allow us to speculate that intra-melanoma DP T cells arise from CD8 SP T cells being reprogrammed to a helper function.

International audience; We previously demonstrated an accumulation of tumor-reactive CD4 + CD8 + double positive (DP) T cells within melanoma-infiltrating lymphocytes, supporting their role in the regulation of anti-tumor immune responses. Similarly to their CD8 + counterparts, intra-tumor DP T cells are MHC class-I restricted but differed by a limited lytic activity against autologous melanoma cells. Based on these observations and to further characterize DP T cells, both populations were compared at the transcriptional level. Our results revealed the overexpression of the IL-9 receptor (IL-9R) by DP T cells and prompted us to investigate the impact of IL-9 on their biology. We show that IL-9 favors DP T-cell survival by protecting them from apoptosis and by promoting their proliferation. In addition, IL-9 enhances their ability to produce cytokines and increased their levels of granzyme B/perforin as well as degranulation capacity, leading to a strengthened cytotoxic activity against melanoma cells. Taken together, the IL-9R high DP T-cell population could be a new preferential target for IL-9, which could take part in their retention within the melanoma infiltrate while also favoring their anti-tumor activity. More generally, our results extend the pleiotropic effects of IL-9 to IL-9R-expressing intra-tumor T cells, which could further potentiate anti-tumor immune responses. Keywords: CD4 + CD8 + double-positive T lymphocyte r IL-9R r IL-9 r Melanoma r TIL Additional supporting information may be found in the online version of this article at the publisher's web-site

International audience; BACKGROUND & AIMS:Faecalibacterium prausnitzii, a member of the Clostridium IV group of the Firmicutes phylum that is abundant in the intestinal microbiota, has anti-inflammatory effects. The relative level of F prausnitzii is decreased in fecal samples from patients with inflammatory bowel diseases (IBDs) compared with healthy individuals. Reduced F prausnitzii was correlated with relapse of Crohn's disease after surgery. We identified, in human colonic mucosa and blood, a population of T regulatory type 1-like T regulatory (TREG) cells that express CD4 and CD8α (DP8α T cells) and are specific for F prausnitzii. We aimed to determine whether they are altered in patients with IBD.METHODS:We isolated DP8α T cells from human colon lamina propria and blood samples and used flow cytometry to detect markers of cells that are of colon origin. We quantified DP8α cells that express colon-specific markers in blood samples from 106 patients with IBD, 12 patients with infectious colitis, and 35 healthy donors (controls). We identified cells that respond to F prausnitzii. Cells were stimulated with anti-CD3, and their production of interleukin 10 was measured by enzyme-linked immunosorbent assay. We compared the frequency and reactivity of cells from patients vs controls using the 2-sided Student t test or 1-way analysis of variance.RESULTS:Circulating DP8α T cells that proliferate in response to F prausnitzii express the C-C motif chemokine receptor 6 (CCR6) and C-X-C motif chemokine receptor 6 (CXCR6). These cells also have features of TREG cells, including production of IL-10 and inhibition of T-cell proliferation via CD39 activity. The proportion of circulating CCR6+/CXCR6+ DP8α T cells was significantly reduced (P < .0001) within the total population of CD3+ T cells from patients with IBD compared with patients with infectious colitis or controls. A threshold of

Faecalibacterium prausnitzii, a member of the Clostridium IV group of the Firmicutes phylum that is abundant in the intestinal microbiota, has anti-inflammatory effects. The relative level of F prausnitzii is decreased in fecal samples from patients with inflammatory bowel diseases (IBDs) compared with healthy individuals. Reduced F prausnitzii was correlated with relapse of Crohn's disease after surgery. We identified, in human colonic mucosa and blood, a population of T regulatory type 1-like T regulatory (TWe isolated DP8α T cells from human colon lamina propria and blood samples and used flow cytometry to detect markers of cells that are of colon origin. We quantified DP8α cells that express colon-specific markers in blood samples from 106 patients with IBD, 12 patients with infectious colitis, and 35 healthy donors (controls). We identified cells that respond to F prausnitzii. Cells were stimulated with anti-CD3, and their production of interleukin 10 was measured by enzyme-linked immunosorbent assay. We compared the frequency and reactivity of cells from patients vs controls using the 2-sided Student t test or 1-way analysis of variance.Circulating DP8α T cells that proliferate in response to F prausnitzii express the C-C motif chemokine receptor 6 (CCR6) and C-X-C motif chemokine receptor 6 (CXCR6). These cells also have features of TWe identified a population of gut-derived T

The uptake and long-term cross-presentation of tumor Ag long peptides (LP) by dendritic cells (DC) make them attractive cancer vaccine candidates. However, it remains to be established whether LP can prime long-lived tumor-reactive CTL and whether other cell types are able to cross-present them. Using HLA-A2 healthy donor and melanoma patient-derived PBMC, we studied the in vitro cross-priming potential of Melan-A 16–40 LP bearing the HLA-A2–restricted epitope 26–35 or its analog 26–35A27L and compared it to the priming capacity of the short analog. We then addressed LP priming capacity in vivo using HLA-A2 mice. We also studied LP cross-presentation by monocyte-derived DC, plasmacytoid DC, monocytes, and B cells. We showed that the modified LP gave rise to high and sustained cross-presentation by monocyte-derived DC. This led to cross priming in vitro and in vivo and to expansion of long-lived tumor-reactive cytotoxic T cells. In contrast, the LP containing the natural 26–35 epitope primed specific T cells poorly, despite its long-lived cross-presentation, and T cells primed against the short analog were short-lived. We further showed that LP cross-presentation is restricted to monocytes and conventional DC. These results document for the first time, to our knowledge, the strong immunogenicity of a human tumor Ag LP. Of note, they underscore that this property is critically dependent on sufficient HLA binding affinity and/or TCR ligand potency of the cross-presented epitope. We conclude that LP fulfilling this requirement should be used as tumor vaccines, together with DC maturating agents, especially the Melan-A 16–40A27L LP, for the treatment of HLA-A2+ melanoma patients.

International audience; We recently showed that the infusion of tumor infiltrating lymphocytes specific for the MELOE-1 antigen was associated with a prolonged relapse-free survival for HLA-A2 1 melanoma patients who received tumor infiltrating lymphocytes therapy. Here, we characterized the MELOE-1/A2-specific T-cell repertoire in healthy donors and melanoma patients to further support an immunotherapy targeting this epitope. Using tetramer enrichment followed by multicolor staining, we found that MELOE-1-specific T cells were present in the blood of healthy donors and patients at similar frequencies (around 1 in 1 Â 10 5 CD8 1 cells). These cells mainly displayed a naïve phenotype in 4/6 healthy donors and 3/6 patients, whereas high proportions of memory cells were observed in the remaining individuals of both groups. There was a recurrent usage of the Va12.1 chain for 17/18 MELOE-1-specific T-cell clones derived from healthy donors or patients, associated with diverse Vb chains and V(D)J junctional sequences. All clones derived from melanoma patients (9/9) were reactive against the MELOE-1 36-44 peptide and against HLA-A2 1 melanoma cell lines. This study documents the existence of a large TCR repertoire specific for the MELOE-1/A2 epitope and its capacity to give rise to antitumor CTL that supports the development of immunotherapies targeting this epitope.

International audience; Background: Double positive (DP) CD4CD8 Tab cells have been reported in normal individuals as well as in different pathological conditions including inflammatory diseases, viral infections and cancer, but their function remains to be elucidated. We recently reported the increased frequency of DP Tab cells in human breast pleural effusions. This manuscript addresses the question of the existence and above all the role of this non-conventional DP sub-population among tumor associated lymphocytes in melanomas. Methodology/Principal Findings: We analyzed the intratumoral cell infiltrate in solid metastasis (n = 6) and tumor invaded lymph nodes (n = 26) samples from melanomas patients by multiparametric cytometry. Here we documented for the first time significant increased frequency of DP T cells in about 60% of melanoma tumors compared to blood samples. Interestingly, a high proportion of these cells produced TNF-a in response to autologous melanoma cell lines. Besides, they are characterized by a unique cytokine profile corresponding to higher secretion of IL-13, IL-4 and IL-5 than simple positive T cells. In deep analysis, we derived a representative tumor-reactive DP T cell clone from a melanoma patient's invaded lymph node. This clone was restricted by HLA-A*2402 and recognized both autologous and allogeneic tumor cells of various origins as well as normal cells, suggesting that the target antigen was a ubiquitous self antigen. However, this DP T cell clone failed to kill HLA-A*2402 EBV-transformed B cells, probably due to the constitutive expression of immunoproteasome by these cells. Conclusions/Significance: In conclusion, we can postulate that, according to their broad tumor reactivity and to their original cytokine profile, the tumor associated DP T cells could participate in immune responses to tumors in vivo. Therefore, the presence of these cells and their role will be crucial to address in cancer patients, especially in the context of immunotherapies.

International audience; Breast cancer remains a leading cause of cancer-related death within the female population. Immunotherapy is expected to provide additional therapeutic benefits but has met so far limited success. This may be due in part to the poor understanding of immune responses to breast cancer. Although CD4 1 and CD8 1 T lymphocytes infiltrate these tumors, the phenotype and functions of these cells remain ill defined. This study was designed to investigate further about these questions, taking advantage of multiparameter flow cytometry on lymphocytes derived from peripheral blood, solid tumors, metastatic lymph nodes and pleural effusions samples of patients with breast cancer. Results showed that, in addition to conventional CD4 1 and CD8 1 ab T cells, individual tumors and most pleural effusions contained significant fractions of unconventional double positive (DP) CD4 1 CD8 1 ab T cells. These DP T cells displayed the phenotype and cytotoxic potential of effector/memory activated CD8 1 T cells but differed essentially from these cells by a high production of IL-5 and IL-13. The increased frequency of DP T cells in advanced breast cancer and their high lytic potential and original cytokine profile suggest that this T-cell subset may play a specific role in the regulation of immune responses to human breast cancer.