Project description:Food allergy affects an estimated 8% of children in the US, with increasing severity and global prevalence. Using single-cell RNA sequencing and paired TCR sequencing, we assessed the transcriptomes of CD154+ and CD137+ peanut-reactive T helper cells from 12 peanut-allergic patients longitudinally throughout peanut oral immunotherapy. These results demonstrate a differential response to OIT among subsets of peanut-reactive T helper cells, and indicate that non-Th2 activation signatures may be associated with clinical outcomes.
Project description:Food allergy affects an estimated 8% of children in the United States. Oral immunotherapy (OIT) is a recently approved treatment, with outcomes ranging from sustained tolerance to food allergens to no apparent benefit. The immunological underpinnings that influence clinical outcomes of OIT remain largely unresolved. Using single-cell RNA-Seq and paired T cell receptor α/β (TCRα/β) sequencing, we assessed the transcriptomes of CD154+ and CD137+ peanut-reactive T helper (Th) cells from 12 patients with peanut allergy longitudinally throughout OIT. We observed expanded populations of cells expressing Th1, Th2, and Th17 signatures that further separated into 6 clonally distinct subsets. Four of these subsets demonstrated a convergence of TCR sequences, suggesting antigen-driven T cell fates. Over the course of OIT, we observed suppression of Th2 and Th1 gene signatures in effector clonotypes but not T follicular helper-like (Tfh-like) clonotypes. Positive outcomes were associated with stronger suppression of Th2 signatures in Th2A-like cells, while treatment failure was associated with the expression of baseline inflammatory gene signatures that were present in Th1 and Th17 cell populations and unmodulated by OIT. These results demonstrate that differential clinical responses to OIT are associated with both preexisting characteristics of peanut-reactive CD4+ T cells and suppression of a subset of Th2 cells.
Project description:B cells constitute abundant cellular components in inflamed human tissues, but their role in pathogenesis of inflammatory T helper (Th) subsets is still unclear. Here, we demonstrate that B cells, particularly resting naïve B cells, have a previously unrecognized helper function that is involved in shaping the metabolic process and subsequent inflammatory differentiation of T-cell-receptor-primed Th cells. ICOS/ICOSL axis-mediated glucose incorporation and utilization were crucial for inflammatory Th subset induction by B cells, and activation of mTOR was critical for T cell glycolysis in this process. Consistently, upon encountering ICOSL+ B cells, activated effector memory Th cells from patients with rheumatoid arthritis or systemic lupus erythematosus spontaneously differentiated into inflammatory Th subsets. Immunotherapy using an anti-CD20 antibody that specifically depleted B cells in patients with rheumatoid arthritis efficiently abrogated the capabilities of memory Th cells to incorporate and utilize glucose, thereby impairing the pathogenic differentiation of inflammatory Th subsets. To examine the metabolic process of Th cells after interacting with autologous B cells, we applied RNA-sequencing to analyze their transcriptional profiles.
Project description:Human T-cells that express CXCR5 and/or CCR6 provide help to naive B-cells for IgG production. To understand the molecular pathways that are shared or unique to individual B helper T-cell subsets in human peripheral blood, CD4+IL-7R+CD25-/lo helper T-cells were purified according to the expression of CXCR5, CCR6, CXCR3, CD161 and CCR5 as follows: 1) TFH17(CD161-): CXCR5+CXCR6+CXCR3-CD161- 2) Th17: CXCR5-CCR6+CXCR3-, CD161+ or CCR5+ 3) CCR6”SP”: CXCR5-CCR6+CXCR3-CD161-CCR5- RNA-seq was performed with FACS-purified T-cell subsets from 3 healthy individuals.
Project description:MS/MS analysis of the peanut protein extract (PPE) confirmed the presence of the four major peanut allergens and identified the presence of Ara h 1 isotypes, Ara h 2 isotypes, Ara h 3 isotypes, Ara h 6 isotypes and Ara h 7 isotypes. Allergen-specific immunotherapy (IT) is emerging as a viable option for treatment of peanut allergy. Yet, prophylactic IT remains unexplored despite early introduction of peanut in infancy was shown to prevent allergy. There is a need to understand how allergens interact with the immune system depending on the route of administration, and how different dosages of allergen may protect from sensitisation and a clinical active allergy. Here we compared peanut allergen delivery via the oral, sublingual (SL), intragastric (IG) and subcutaneous (SC) routes for the prevention of peanut allergy in Brown Norway (BN) rats. BN rats were administered PBS or three different doses of PPE via either oral IT (OIT), SLIT, IGIT and SCIT followed by intraperitoneal (IP) injections of PPE to assess the protection from peanut sensitisation. The development of IgE and IgG1 responses to PPE and the major peanut allergens were evaluated by ELISAs. The clinical response to PPE was assessed by an ear swelling test (EST) and proliferation was assessed by stimulating splenocytes with PPE. Low and medium dose OIT (1 and 10 mg) and all doses of SCIT (1, 10, 100 µg) induced sensitisation to PPE, whereas high dose OIT (100 mg), SLIT (10, 100 or 1000 µg) or IGIT (1, 10 and 100 mg) did not. High dose OIT and SLIT as well as high and medium dose IGIT prevented sensitisation from the following IP injections of PPE and suppressed PPE-specific IgE levels in a dose-dependent manner. Hence, administration of peanut protein via different routes confers different risks for sensitisation and protection from peanut allergy development. Overall, the IgE levels toward the individual major peanut allergens followed the PPE-specific IgE levels. Collectively, this study showed that the preventive effect of allergen-specific IT is determined by the interplay between the specific site of PPE delivery for presentation to the immune system, and the allergen quantity, and that targeting and modulating tolerance mechanisms at specific mucosal sites may be a prophylactic strategy for prevention of peanut allergy.
Project description:Peanut allergy reaction severity correlates with increased intestinal epithelial cell (IEC) barrier permeability. CC027/GeniUnc mice develop peanut allergy by intragastric administration of peanut proteins without adjuvant. We report that peanut-allergic CC027/GeniUnc mice showed increased IEC barrier permeability and systemic peanut allergen Ara h 2 after challenge. Jejunal epithelial cell transcriptomics showed effects of peanut allergy on IEC proliferation, survival, and metabolism, and revealed IEC-predominant angiopoietin like-4 (Angptl4) as a unique feature of CC027/GeniUnc peanut allergy. Peanut-allergic pediatric patients demonstrated significantly higher serum ANGPTL4 compared to non-peanut-allergic but atopic patients, highlighting its potential as a biomarker of peanut allergy.
Project description:Peanut-responsive T cells from peanut allergic subjects were identified and selected based on CD154 expression after stimulation of peripheral blood mononuclear cells with crude peanut extract for 18h. As controls, polyclonally activated CD4+ T cells from peanut allergic subjects were selected. Additional controls included CD4+CD25+CD127- Tregs from peanut allergic or healthy controls. Single cells were obtained using the C1 system from Fluidigm, and a barcoded library constructed. Sequencing (Illumina) was performed using 100 nt paired end reads. Data on a total of 431 cells was available. The goal of the study was to understand the heterogeneity of the peanut-specific T cell response.
Project description:Peanut allergy is increasingly prevalent among children in the United States and other industrialized countries and is now estimated to affect approximately 2% of children. While there are currently no approved treatment options, peanut allergy usually persists into adulthood, can be life-threatening, and accounts for most deaths related to food allergy. Here, we track peanut-reactive CD4+ T effector (pTeff) cells using the CD154 up-regulation assay. We found that CRTH2+ pTeff cells and CCR6+ pTeff cells represent two mutually exclusive, non-overlapping cellular and molecular entities involved in food allergic diseases.